Difference between manual and digital measurements of dental arches of orthodontic patients.

PubMed

Jiménez-Gayosso, Sandra Isabel; Lara-Carrillo, Edith; López-González, Saraí; Medina-Solís, Carlo Eduardo; Scougall-Vilchis, Rogelio José; Hernández-Martínez, César Tadeo; Colomé-Ruiz, Gabriel Eduardo; Escoffié-Ramirez, Mauricio

2018-06-01

The objective of this study was to compare the differences between the measurements performed manually to those obtained using a digital model scanner of patients with orthodontic treatment.A cross-sectional study was performed in a sample of 30 study models from patients with permanent dentition who attended a university clinic between January 2010 and December 2015. For the digital measurement, a Maestro 3D Ortho Studio scanner (Italy) was used and Mitutoyo electronic Vernier calipers (Kawasaki, Japan) were used for manual measurement. The outcome variables were the measurements for maxillary intercanine width, mandibular intercanine width, maxillary intermolar width, mandibular intermolar width, overjet, overbite, maxillary arch perimeter, mandibular arch perimeter, and palate height. The independent variables, besides age and sex, were a series of arc characteristics. The Student t test, paired Student t test, and Pearson correlation in SPSS version 19 were used for the analysis.Of the models, 60% were from women. Two of nine measurements for pre-treatment and 6 of 9 measurements for post-treatment showed a difference. The variables that were different between the manual and digital measurements in the pre-treatment were maxillary intermolar width and palate height (P < .05). Post-treatment, differences were found in mandibular intercanine width, palate height, overjet, overbite, and maxillary and mandibular arch perimeter (P < .05).The models measured manually and digitally showed certain similarities for both vertical and transverse measurements. There are many advantages offered to the orthodontist, such as easy storage; savings in time and space; facilitating the reproducibility of information; and conferring the security of not deteriorating over time. Its main disadvantage is the cost.

Customized mandibular reconstruction plates improve mechanical performance in a mandibular reconstruction model

PubMed Central

Gutwald, Ralf; Jaeger, Raimund; Lambers, Floor M.

2017-01-01

Abstract The purpose of this paper was to analyze the biomechanical performance of customized mandibular reconstruction plates with optimized strength. The best locations for increasing bar widths were determined with a sensitivity analysis. Standard and customized plates were mounted on mandible models and mechanically tested. Maximum stress in the plate could be reduced from 573 to 393 MPa (−31%) by increasing bar widths. The median fatigue limit was significantly greater (p < 0.001) for customized plates (650 ± 27 N) than for standard plates (475 ± 27 N). Increasing bar widths at case-specific locations was an effective strategy for increasing plate fatigue performance. PMID:27887036

Association of the canine guidance angle with maxillary and mandibular intercanine widths and anterior alignment relapse: Extraction vs nonextraction treatment.

PubMed

Heiser, Wolfgang; Richter, Martin; Niederwanger, Andreas; Neunteufel, Nikolaus; Kulmer, Siegfried

2008-05-01

Long-term stability is an important measure of the success of orthodontic treatment. Research in the 1970s suggested that premolar extraction treatment had poor stability over the long term. The purpose of this prospective follow-up study was to investigate changes in intercanine widths and the irregularity index during the postretention phase in patients treated with and without extractions. Associations between the maxillary canine guidance angle and the mandibular intercanine widths and the mandibular irregularity index were also examined. Two groups of 30 patients each, with and without premolar extractions, were studied and the results compared. Records were taken at pretreatment, at bracket removal, at the end of retention, and out of retention. The times out of retention were 6.3 years for the nonextraction group and 6.5 years for the extraction group. Stone casts were mounted on an articulator with an anatomical facebow and a central wax record. The measurements were made with a 3-dimensional digitizer. Maxillary and mandibular intercanine distances behaved differently. The mandibular intercanine distance showed a net decrease between pretreatment and follow-up, whereas the maxillary arch had a net increase. The maxillary canine guidance angle at the end of retention, measured to the axis-orbital plane, was highly associated with relapse of mandibular anterior alignment and change of the mandibular intercanine distance. Methods are needed that consider the anatomical configuration of the teeth for bracket selection before treatment. Individualized brackets (torque) should then be coordinated with the guidance angle of the maxillary teeth.

Effect of rotopositioning on the growth and maturation of mandibular bone in immobilized Rhesus monkeys

NASA Technical Reports Server (NTRS)

Simmons, D. J.; Parvin, C.; Smith, K. C.; France, P.; Kazarian, L.

1986-01-01

The rates of bone formation and mineralization in the mandibular cortex of juvenile Rhesus monkeys exposed to immobilization/rotopositioning are evaluated. The monkeys were restrained in a supine position and rotated 90 deg every 30 minutes through a full 360 deg for 14 days. The microscopic distribution of mineral densities in osteonal bone and the porosity of cortical bone are studied using microradiographs, and osteon closure rates are assessed using tetracycline labeling; normal distributions of osteons of different mineral density and cortical bone porosity values are observed. It is concluded that 14 days of immobilization/rotopositioning did not cause abnormal changes in osteon mineralization, cortical porosity, and osteon closure rates.

An assessment of early mandibular growth.

PubMed

Hutchinson, E F; L'Abbé, E N; Oettlé, A C

2012-04-10

Quantification of skeletal data has been shown to be an effective and reliable method of demonstrating variation in human growth as well as for monitoring and interpreting growth. In South Africa as well as internationally, few researchers have assessed mandibular growth in late fetal period and early childhood and therefore standards for growth and age determination in these groups are limited. The purpose of this study was to evaluate growth in the mandible from the period of 31 gestational weeks to 36 months postnatal. A total of 74 mandibles were used. Dried mandibles were sourced from the Raymond A. Dart Collection (University of Witwatersrand), and cadaveric remains were obtained from the Universities of Pretoria and the Witwatersrand. The sample was divided into four groups; 31-40 gestational weeks (group 1), 0-11 months (group 2), 12-24 months (group 3), and 25-36 months (group 4). Twenty-one osteological landmarks were digitized using a MicroScribe G2. Ten standard measurements were created and included: the maximum length of mandible, mandibular body length and width, mandibular notch width and depth, mental foramen to inferior border of mandible, mandibular basilar widths bigonial and biantegonial, bigonial width of mental foramen and mental angle. Data were analyzed using PAST statistical software and Morphologika2 v2.5. Statistically significant differences were noted in the linear measurements for all group comparisons except between groups 3 and 4. The mandible morphologically changed from a round, smooth contour anteriorly to adopt a more sharp and narrow adult shape. A progressive increase in the depth and definition of the mandibular arch was also noted. In conclusion, the mandible initially grows to accommodate the developing tongue (up to 11 months), progressive dental eruption and mastication from 12 to 36 months. Mastication is associated with muscle mass development; this would necessitate an increase in the dimensions of the mandibular notch and associated muscle attachment sites. These findings might be valuable in the estimation of age in unidentified individuals and to monitor prenatal growth of the mandible for the early diagnosis of conditions associated with stunted mandibular growth. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Autotransplantation of Mandibular Third Molar with Buccal Cortical Plate to Replace Vertically Fractured Mandibular Second Molar: A Novel Technique.

PubMed

Zufía, Juan; Abella, Francesc; Trebol, Ivan; Gómez-Meda, Ramón

2017-09-01

Tooth replacement often leads to inadequate vertical volume in the recipient site bone when a tooth has been extracted because of a vertical root fracture (VRF). This case report presents the autotransplantation of a mandibular third molar (tooth #32) with the attached buccal cortical plate to replace a mandibular second molar (tooth #31) diagnosed with a VRF. After extraction of tooth #31, the recipient socket was prepared based on the size measured in advance with cone-beam computed tomographic imaging. The precise and calculated osteotomy of the cortical bone of tooth #32 allowed for the exact placement of the donor tooth in the position of tooth #31. The total extraoral time was only 25 minutes. The block was fixed to the recipient socket with an osteosynthesis screw and splinted with a double resin wire for 8 weeks. At the 6-month follow-up, the screw was removed, and the stability of the tooth and the regeneration obtained throughout the vestibular area were confirmed. At the 2-year follow-up, the transplanted tooth was asymptomatic and maintained a normal bone level. Advantages of autotransplantation over dental implants include maintenance of proprioception, possible orthodontic movements, and a relatively low cost. This case report demonstrates that an autotransplantation of a third molar attached to its buccal cortical plate is a viable option to replace teeth with a VRF. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Accuracy of three-dimensional dental resin models created by fused deposition modeling, stereolithography, and Polyjet prototype technologies: A comparative study.

PubMed

Rebong, Raymund E; Stewart, Kelton T; Utreja, Achint; Ghoneima, Ahmed A

2018-05-01

The aim of this study was to assess the dimensional accuracy of fused deposition modeling (FDM)-, Polyjet-, and stereolithography (SLA)-produced models by comparing them to traditional plaster casts. A total of 12 maxillary and mandibular posttreatment orthodontic plaster casts were selected from the archives of the Orthodontic Department at the Indiana University School of Dentistry. Plaster models were scanned, saved as stereolithography files, and printed as physical models using three different three-dimensional (3D) printers: Makerbot Replicator (FDM), 3D Systems SLA 6000 (SLA), and Objet Eden500V (Polyjet). A digital caliper was used to obtain measurements on the original plaster models as well as on the printed resin models. Comparison between the 3D printed models and the plaster casts showed no statistically significant differences in most of the parameters. However, FDM was significantly higher on average than were plaster casts in maxillary left mixed plane (MxL-MP) and mandibular intermolar width (Md-IMW). Polyjet was significantly higher on average than were plaster casts in maxillary intercanine width (Mx-ICW), mandibular intercanine width (Md-ICW), and mandibular left mixed plane (MdL-MP). Polyjet was significantly lower on average than were plaster casts in maxillary right vertical plane (MxR-vertical), maxillary left vertical plane (MxL-vertical), mandibular right anteroposterior plane (MdR-AP), mandibular right vertical plane (MdR-vertical), and mandibular left vertical plane (MdL-vertical). SLA was significantly higher on average than were plaster casts in MxL-MP, Md-ICW, and overbite. SLA was significantly lower on average than were plaster casts in MdR-vertical and MdL-vertical. Dental models reconstructed by FDM technology had the fewest dimensional measurement differences compared to plaster models.

The Application of 3D Printing Technology for Simultaneous Orthognathic Surgery and Mandibular Contour Osteoplasty in the Treatment of Craniofacial Deformities.

PubMed

Xiao, Yanju; Sun, Xiumei; Wang, Lin; Zhang, Yaoyao; Chen, Kai; Wu, Guomin

2017-12-01

Because of the limitation of specific preoperative design and surgical templates, orthognathic surgery and mandibular contour osteoplasty are generally performed in two stages. Three-dimensional printing technology has improved the accuracy of the surgery and results in good surgical predictability easily. This study aims to confirm the effectiveness, feasibility and precision of simultaneous mandibular contour osteoplasty and orthognathic surgery with the assistance of 3D printing technology. Ten patients, who were diagnosed with mandibular hypertrophy and bimaxillary deformities, were included in the study. In addition to conventional orthognathic surgery, mandibular angle ostectomy, mandibular outer cortex grinding or mandibular border ostectomy was designed for mandibular hypertrophy. Optimal osteotomy lines and simulated surgeries were designed according the 3D printing model of the mandible. Then, surgical templates were made on the 3D printing model. No muscle excision was performed in any patient. Preoperative, predicted and postoperative measurements were taken, including the gonial angle (Ar-Go-Me) and the mandibular width (Go-Go). All the patients had a reposeful postoperative recovery, with no indication of obvious infection, facial paralysis, osteonecrosis or bone displacement. The gonial angle was improved from 110.3° ± 11.1 to 121.3° ± 2.9, and the mandibular width was improved from 117.5 mm ± 6.8 to 111.9 mm ± 4.2. The discrepancies between simulation and postoperation of the left gonial angle, the right gonial angle and the mandibular width were 0.56° ± 0.22, 0.65° ± 0.3 and 0.49 mm ± 0.43, respectively. The results of our study illustrated the predictability, feasibility and reliability of simultaneous mandibular contour osteoplasty and orthognathic surgery with the assistance of 3D printing technology. Our technique could achieve functional improvement and an aesthetic profile at the same time. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Dentoalveolar mandibular changes with self-ligating versus conventional bracket systems: A CBCT and dental cast study

PubMed Central

de Almeida, Marcio Rodrigues; Futagami, Cristina; Conti, Ana Cláudia de Castro Ferreira; Oltramari-Navarro, Paula Vanessa Pedron; Navarro, Ricardo de Lima

2015-01-01

OBJECTIVE: The aim of the present study was to compare dentoalveolar changes in mandibular arch, regarding transversal measures and buccal bone thickness, in patients undergoing the initial phase of orthodontic treatment with self-ligating or conventional bracket systems. METHODS: A sample of 25 patients requiring orthodontic treatment was assessed based on the bracket type. Group 1 comprised 13 patients bonded with 0.022-in self-ligating brackets (SLB). Group 2 included 12 patients bonded with 0.022-in conventional brackets (CLB). Cone-beam computed tomography (CBCT) scans and a 3D program (Dolphin) assessed changes in transversal width of buccal bone (TWBB) and buccal bone thickness (BBT) before (T1) and 7 months after treatment onset (T2). Measurements on dental casts were performed using a digital caliper. Differences between and within groups were analyzed by Student's t-test; Pearson correlation coefficient was also calculated. RESULTS: Significant mandibular expansion was observed for both groups; however, no significant differences were found between groups. There was significant decrease in mandibular buccal bone thickness and transversal width of buccal bone in both groups. There was no significant correlation between buccal bone thickness and dental arch expansion. CONCLUSIONS: There were no significant differences between self-ligating brackets and conventional brackets systems regarding mandibular arch expansion and changes in buccal bone thickness or transversal width of buccal bone. PMID:26154456

Changes in jawbones of male patients with chronic renal failure on digital panoramic radiographs.

PubMed

Dagistan, Saadettin; Miloglu, Ozkan; Caglayan, Fatma

2016-01-01

To compare the existence of gonial cortical bone thickness, antegonial index, mandibular canal bone resorption and gonial angle values and pathologies like ground-glass appearance in jawbones and brown tumor in male patients undergoing dialysis due to chronic renal failure and men from the healthy control group on panoramic radiographs. Panoramic radiographs were taken from 80 male individuals in total (40 normal and 40 dialysis patients). Values obtained from the right and left sides of the mandible were summed and their means were calculated. Gonial cortical thickness, antegonial index and gonial angle values were assessed with the Student's t-test, mandibular canal wall resorption with the Chi-square test, and pathologies such as ground-glass appearance and Brown tumor as "available" or "not available." Statistically significant differences were observed among the antegonial index (P < 0.001), gonial cortical bone thickness (P < 0.001), and gonial angle (P < 0.001) values of study and control groups. Besides, mandibular canal wall resorption (P < 0.001) was also statistically significant. In the study group, pathologies with ground-glass appearance were encountered in mandible, but no radiographic findings were observed similar to brown tumor. Compared to the control group, decreases were found in gonial cortical bone thicknesses, antegonial index values, mandibular canal wall resorption, and gonial angle values of the patients receiving dialysis treatment due to chronic renal failure. Although it is not statistically significant, pathology with ground-glass appearance was detected in a patient, but no pathologies like brown tumor were observed. These findings from patients with chronic renal failure must be evaluated in panoramic radiography.

Development of a Drilling Simulator for Dental Implant Surgery.

PubMed

Kinoshita, Hideaki; Nagahata, Masahiro; Takano, Naoki; Takemoto, Shinji; Matsunaga, Satoru; Abe, Shinichi; Yoshinari, Masao; Kawada, Eiji

2016-01-01

The aim of this study was to develop and evaluate a dental implant surgery simulator that allows learners to experience the drilling forces necessary to perform an osteotomy in the posterior mandibular bone. The simulator contains a force-sensing device that receives input and counteracts this force, which is felt as resistance by the user. The device consists of an actuator, a load cell, and a control unit. A mandibular bone model was fabricated in which the predicted forces necessary to drill the cortical and trabecular bone were determined via micro CT image-based 3D finite element analysis. The simulator was evaluated by five dentists from the Department of Implantology at Tokyo Dental College. The ability of the evaluators to distinguish the drilling resistance through different regions of the mandibular bone was investigated. Of the five dentists, four sensed the change in resistance when the drill perforated the upper cortical bone. All five dentists were able to detect when the drill made contact with lingual cortical bone and when the lingual bone was perforated. This project successfully developed a dental implant surgery simulator that allows users to experience the forces necessary to drill through types of bone encountered during osteotomy. Furthermore, the researchers were able to build a device by which excessive drilling simulates a situation in which the lingual cortical bone is perforated--a situation that could lead to negative repercussions in a clinical setting. The simulator was found to be useful to train users to recognize the differences in resistance when drilling through the mandibular bone.

The self adapting washer for lag screw fixation of mandibular fractures: finite element analysis and preclinical evaluation.

PubMed

Terheyden, H; Mühlendyck, C; Feldmann, H; Ludwig, K; Härle, F

1999-02-01

Besides rigid fixation, lag screws have distinct advantages compared with plates in appropriate indications in mandibular fractures. However, in current lag screw systems, the relatively small area of the screw head has to transfer the tensile force which can exceed 1000 N in the symphysis, to the thin cortical bone plate. Countersinking, which is obligatory in most systems, will weaken the cortical plate. Finite element analysis (FEA) revealed that load in this situation can exceed the normal tensile strength of metal and bone. Consequently, a new washer was constructed which both increased the supporting surface and did not require countersinking. The washer is self adapting (SAW) to the cortical plate in a defined position, forming a ball and socket joint with the screw head. Using the FEA model, a ten-fold reduction in load on bone and metal was observed with the new washer. In a miniature pig mandibular symphysis fracture model, the clinical applicability and a favourable histological reaction were demonstrated, compared with conventional lag screw designs.

Preliminary cone-beam computed tomography study evaluating dental and skeletal changes after treatment with a mandibular Schwarz appliance.

PubMed

Tai, Kiyoshi; Hotokezaka, Hitoshi; Park, Jae Hyun; Tai, Hisako; Miyajima, Kuniaki; Choi, Matthew; Kai, Lisa M; Mishima, Katsuaki

2010-09-01

The purpose of this study was to evaluate the efficacy of the Schwarz appliance with a new method of superimposing detailed cone-beam computed tomography (CBCT) images. The subjects were 28 patients with Angle Class I molar relationships and crowding; they were randomly divided into 2 groups: 14 expanded and 14 nonexpanded patients. Three-dimensional Rugle CBCT software (Medic Engineering, Kyoto, Japan) was used to measure 10 reference points before treatment (T0) and during the retention period of approximately 9 months after 6 to 12 months of expansion (T1). Cephalometric and cast measurements were used to evaluate the treatments in both groups. Also, the mandibular widths of both groups were measured along an axial plane at 2 levels below the cementoenamel junction from a CBCT scan. Differences between the 2 groups at T0 and T1 were analyzed by using the Mann-Whitney U test. The dental arch (including tooth root apices) had expanded; however, alveolar bone expansion was only up to 2 mm below the cementoenamel junction. There was a statistically significant (P <0.05) difference between the groups in terms of crown, cementoenamel junction, root, and upper alveolar process. However, no significant (P >0.05) differences were observed in the interwidths of the mandibular body, zygomatic bones, condylar heads, or mandibular antegonial notches. In the mandibular cast measurements, arch crowding and arch perimeter showed statistically significant changes in the expanded group. The buccal mandibular width and lingual mandibular width values had significant changes as measured from a point 2 mm below the cementoenamel junction. The findings suggest that the Schwarz appliance primarily affected the dentoalveolar complex, but it had little effect on either the mandibular body or any associated structures. In addition, the molar center of rotation was observed to be below the root apex. 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

An experimental study of arch perimeter and arch width increase with mandibular expansion: a finite element method.

PubMed

Baswaraj; Hemanth, M; Jayasudha; Patil, Chandrashekhargouda; Sunilkumar, P; Raghuveer, H P; Chandralekha, B

2013-01-01

The objective of this study was to estimate the increase in arch perimeter associated with mandibular lateral expansion, To estimate the increase in intermolar width with mandibular lateral expansion and to find out the changes of tooth inclination with mandibular expansion. The mandibular bone with dentition of indian skeletal specimen was obtained. The computer tomogram (CT) slices of the mandible were taken. Finite element model (FEM): Numerical representation of the geometry was created by dividing the geometry into finite number of elements and the elements were connected together with nodes at the junction. The result of the study showed when 10° of lateral expansion was applied to the lower buccal segment at the center of rotation found at 4.3 mm below the root apex of first molar, a space of 1.3 mm between the canine and first premolar, and thus an increase in arch perimeter of 2.6 mm. The tip of the mesiolingual cusp of the first molar moved 4.2 mm laterally, resulting in a change in intermolar width by 8.4 mm. Three-dimensional simulation showed that 1 mm of intermolar expansion increased the arch perimeter by 0.30 mm. As the finite element method evolves and scientists are able to more clearly define physical properties of biological tissues, more accurate information can be generated at the level that other analytical methods cannot fully provide data.This result would be of value clinically for prediction of the effects of mandibular expansion.

Finite element analysis of dental implant loading on atrophic and non-atrophic cancellous and cortical mandibular bone - a feasibility study.

PubMed

Marcián, Petr; Borák, Libor; Valášek, Jiří; Kaiser, Jozef; Florian, Zdeněk; Wolff, Jan

2014-12-18

The first aim of this study was to assess displacements and micro-strain induced on different grades of atrophic cortical and trabecular mandibular bone by axially loaded dental implants using finite element analysis (FEA). The second aim was to assess the micro-strain induced by different implant geometries and the levels of bone-to-implant contact (BIC) on the surrounding bone. Six mandibular bone segments demonstrating different grades of mandibular bone atrophy and various bone volume fractions (from 0.149 to 0.471) were imaged using a micro-CT device. The acquired bone STL models and implant (Brånemark, Straumann, Ankylos) were merged into a three-dimensional finite elements structure. The mean displacement value for all implants was 3.1 ±1.2 µm. Displacements were lower in the group with a strong BIC. The results indicated that the maximum strain values of cortical and cancellous bone increased with lower bone density. Strain distribution is the first and foremost dependent on the shape of bone and architecture of cancellous bone. The geometry of the implant, thread patterns, grade of bone atrophy and BIC all affect the displacement and micro-strain on the mandible bone. Preoperative finite element analysis could offer improved predictability in the long-term outlook of dental implant restorations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of validity of Tanaka-Johnston analysis in Mumbai school children.

PubMed

Hambire, Chaitali Umesh; Sujan, Sunanda

2015-01-01

Estimation of the mesiodistal dimensions of the unerupted canines and premolars in the early mixed dentition is a necessary diagnostic aid in space management. Tanaka-Johnston analysis was developed for North American children. Anthropological study reveals that tooth size varies among different ethnicities. The present study was performed to evaluate the validity of Tanaka-Johnston method of mixed dentition arch analysis in Mumbai school children. (1) To determine the correlation between the sum of the mesiodistal widths of the permanent mandibular incisors and combined mesiodistal widths of the permanent mandibular and maxillary canines and premolar in Mumbai school children. (2) To examine the applicability of Tanaka-Johnston method of prediction. Dental casts of maxillary and mandibular arches of 300 children, 147 boys and 153 girls within the age group of 12-15 years, with permanent dentitions were fabricated. The mesiodistal crown dimensions of teeth were measured with a dial caliper. Tanaka-Johnston method of mixed dentition arch analysis was performed for the study population, and statistical analysis was done. Descriptive statistics including the mean, standard deviation, range, and standard error were calculated and tabulated. Tanaka-Johnston's equation when applied to the data available for Mumbai school children, it was observed that it slightly overestimates the tooth size. (1) There was a positive correlation between the width of mandibular incisors and mandibular and maxillary canines and premolars. (2) The Tanaka-Johnston prediction method was not accurate for a sample of Mumbai school children.

Skeletal and dental changes in the sagittal, vertical, and transverse dimensions after rapid palatal expansion.

PubMed

Chung, Chun-Hsi; Font, Blanca

2004-11-01

The purpose of this study was to examine the maxillary and mandibular responses to rapid palatal expansion (RPE) in all 3 dimensions. Twenty children (average age, 11.7 years) who required RPE treatment were included in this study. Pre- (T1) and post-RPE (T2) lateral and posteroanterior (PA) cephalograms and study models were taken for all patients. For each patient, lateral and PA cephalograms at T1 and T2 were traced, and the sagittal, vertical, and transverse measurements were made. In addition, on the pre- and postexpansion models, the widths between the first premolars, the first molars, and the two acrylic halves of the Haas-type expander were measured. Results showed that from T1 to T2, the mean SNA increased 0.35 degrees (P < .05) and ANB increased 1.00 degrees (P < .05). Both the ANS and PNS moved downward (1.30 mm and 1.43 mm, respectively, P < .05), and the mandibular plane angle (MP-SN) increased 1.72 degrees (P < .05). The maxillary and mandibular incisors did not change significantly after RPE. After RPE, the mean increase of maxillary interpremolar width, maxillary intermolar width, maxillary width (J-J), nasal width, and interorbital width were found to be 110.7%, 104.5%, 30.1%, 23.1%, and 3.3% of the screw expansion, respectively. After RPE treatment in children, the maxilla displaced slightly forward and downward (P < .05); the mandible rotated downward and backward, and the anterior facial height increased significantly (P < .05); and the widths of the maxilla and nasal cavity increased significantly (P < .05).

Vertical facial height and its correlation with facial width and depth: Three dimensional cone beam computed tomography evaluation based on dry skulls.

PubMed

Wang, Ming Feng; Otsuka, Takero; Akimoto, Susumu; Sato, Sadao

2013-01-01

The aim of the present study was to evaluate how vertical facial height correlates with mandibular plane angle, facial width and depth from a three dimensional (3D) viewing angle. In this study 3D cephalometric landmarks were identified and measurements from 43 randomly selected cone beam computed tomography (CBCT) images of dry skulls from the Weisbach collection of Vienna Natural History Museum were analyzed. Pearson correlation coefficients of facial height measurements and mandibular plane angle and the correlation coefficients of height-width and height-depth were calculated, respectively. The mandibular plane angle (MP-SN) significantly correlated with ramus height (Co-Go) and posterior facial height (PFH) but not with anterior lower face height (ALFH) or anterior total face height (ATFH). The ALFH and ATFH showed significant correlation with anterior cranial base length (S-N), whereas PFH showed significant correlation with the mandible (S-B) and maxilla (S-A) anteroposterior position. High or low mandibular plane angle might not necessarily be accompanied by long or short anterior face height, respectively. The PFH rather than AFH is assumed to play a key role in the vertical facial type whereas AFH seems to undergo relatively intrinsic growth.

Mandibular canine: A tool for sex identification in forensic odontology.

PubMed

Kumawat, Ramniwas M; Dindgire, Sarika L; Gadhari, Mangesh; Khobragade, Pratima G; Kadoo, Priyanka S; Yadav, Pradeep

2017-01-01

The aim of this study was to investigate the accuracy of mandibular canine index (MCI) and mandibular mesiodistal odontometrics in sex identification in the age group of 17-25 years in central Indian population. The study sample comprised total 300 individuals (150 males and 150 females) of an age group ranging from 17 to 25 years of central Indian population. The maximum mesiodistal diameter of mandibular canines, the linear distance between the tips of mandibular canines, was measured using digital vernier caliper on the study models. Overall sex could be predicted accurately in 79.66% (81.33% males and 78% females) of the population by MCI. Whereas, considering the mandibular canine width for sex identification, the overall accuracy was 75% for the right mandibular canine and 73% for the left mandibular canine observed. Sexual dimorphism of canine is population specific, and among the Indian population, MCI and mesiodistal dimension of mandibular canine can aid in sex determination.

Dentofacial transverse development in Koreans according to skeletal maturation: A cross-sectional study.

PubMed

Hwang, Soonshin; Noh, Yoonjeong; Choi, Yoon Jeong; Chung, Chooryung; Lee, Hye Sun; Kim, Kyung-Ho

2018-01-01

The aim of this study was to establish the normative data of dentofacial transverse dimensions according to the skeletal maturation stage in Korean adolescents with good occlusion, assess gender differences and determine correlations between transverse variables. A total of 577 Korean subjects between ages 7 to 19 years and exhibiting skeletal Class I occlusion were categorized by skeletal maturation index (SMI) of Fishman using hand-wrist radiographs. Dentofacial transverse dimensions were assessed using posteroanterior cephalograms. Independent two-sample t -tests were used to analyze differences between genders. Pearson correlation coefficient was used to determine the correlation between transverse measurements. Dentofacial transverse norms relevant to skeletal maturation stages were established. The average maxillomandibular width difference and ratio at growth completion was 22.16 mm and 77.01% for males; 23.70 mm and 74.06% for females, respectively. Males had greater facial, maxillary and mandibular widths compared to females at every SMI stage. The maxillary and mandibular intermolar widths showed the strongest correlation for both sexes (r = 0.826 for males, r = 0.725 for females). Dentofacial transverse norms of Korean adolescents were established according to developmental stage. All dentofacial widths were greater in males at growth completion. Maxillary and mandibular intermolar widths were strongly correlated. This study may serve as a guideline for the assessment of dentofacial transverse growth according to skeletal maturation stage in Korean adolescents with good occlusion.

Mandibular canine index: A study for gender determination in Gandhinagar population

PubMed Central

Patel, Roseline Ankit; Chaudhary, Anjani Ramchandra; Dudhia, Bhavin Bipinchandra; Macwan, Zonty Sylvestor; Patel, Purv Shashank; Jani, Yesha Vijaykumar

2017-01-01

Introduction: One of the important pieces of information gathered from tooth analysis is the sex of an individual. In most human living populations, mandibular canines show the greatest dimorphism and greatest dimensional differences between males and females. In view of these facts, the aim of this study was to establish the standard mandibular canine index (MCI) and estimate the sexual dimorphism in the population of Gandhinagar district of Gujarat state. Materials and Methods: The study consisted of 400 subjects, 200 males and 200 females in the age group of 20–40 years. The mesiodistal (MD) width of the right and left canine and the intercanine distance were measured. These values were used to derive the MCI and establish the amount of sexual dimorphism exhibited by the mandibular canine. Results: The MD crown width of the permanent mandibular right and left canines as well as mandibular intercanine distance of the males was found to be larger in size than in the females. The right mandibular canine exhibited 8.42% of sexual dimorphism while the left mandibular canine exhibited 8.40% of sexual dimorphism. The intercanine distance showed 2.75% of sexual dimorphism. The value of standard MCI derived using the formula devised by Rao et al. was 0.254 mm for the population residing in the Gandhinagar district. Conclusion: The present study supports the usefulness of the MCI in gender determination. The method of using mandibular canine indices is advantageous as it is easy, rapid, and cost-effective, requires no elaborate apparatus, and is suited for situations where large a number of samples have to be analyzed. PMID:29657490

Three-dimensional facial architecture in normodivergent class I Caucasian subjects.

PubMed

Ghoubril, J V; Abou Obeid, F M

2013-06-01

The aims of this study were to (1) define facial architecture in Caucasian patients with normodivergent, skeletal and dental class I using Treil's cephalometric analysis, which is based on computed tomography (CT), and (2) develop a scheme to determine individual balance or normality in relation to linear, angular and volumetric parameters. The CT data of 60 adult subjects were equally divided between both genders. Based on anatomical points located along the trigeminal neuro-matricial facial growth axes, a three-dimensional maxillo-facial architecture was constructed. Volumetric and linear parameters were greater in males (0.000 < p < 0.044) except for the anterior and posterior mandibular width. Sexual dimorphism was not observed with angular parameters. There was no correlation between volumetric and angular parameters. The correlation tests showed that the total volume of the frame increases with infraorbital depth, supraorbital depth, posterior mandibular width and facial height (0.526 < r < 0.777), while it was not associated with the maxillo-orbital width (0.252 < r < 0.389). Total and orbital volumes were more correlated with posterior than with anterior mandibular width. Maxillo-mandibular volume of the frame was more cor-related with orbital depth (0.591 < r < 0.742) than the orbital volume (0.482 < r < 0.589). The results allowed us to establish three-dimensional cephalometric standards, and to replace the tenet of normality, which is a mean value of calculated parameters, by the concept of individual balance among volumetric entities. While sagittal and vertical dimensions affect volumetric changes of the frame, the transverse dimension does not.

Dental arch dimensional changes after adenotonsillectomy in prepubertal children.

PubMed

Petraccone Caixeta, Anna Cristina; Andrade, Ildeu; Bahia Junqueira Pereira, Tatiana; Franco, Letícia Paiva; Becker, Helena Maria Gonçalves; Souki, Bernardo Quiroga

2014-04-01

The purposes of this study were to investigate the dental arch changes after adenotonsillectomies in prepubertal children and to compare the dental arch dimensions of mouth-breathing and nasal-breathing children. The sample included 49 prepubertal severely obstructed mouth-breathing children and 46 prepubertal nasal-breathing children. Twenty-four of the 49 mouth-breathing children had an adenotonsillectomy and composed the adenotonsillectomy subgroup. The 25 children in whom the mouth-breathing pattern was unchanged during the 1-year study period composed the control subgroup. The mouth-breathing children showed a deeper palatal vault, a larger mandibular width, and a larger mandibular arch length in comparison with the nasal-breathing children. After airway clearance, the adenotonsillectomy group showed a significant maxillary transverse width gain compared with the control subgroup. The control subgroup showed a significant deepening of the palatal height when compared with the adenotonsillectomy subgroup after 1 year. The adenotonsillectomy subgroup had a significantly different pattern of arch development compared with the untreated controls. After adenotonsillectomy, the mouth-breathing children showed greater maxillary transverse development than did the controls. The palatal vault deepened in the untreated children. The mouth-breathing children showed a deeper palatal vault, a larger mandibular width, and a larger mandibular arch length in comparison with the nasal-breathing children. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Correction of the transverse discrepancy-induced spontaneous mandibular protrusion in Class II Division 1 adolescent patients.

PubMed

Yu, Yanfang; Wu, Mengjie; Chen, Xuepeng; Li, Wen

2016-11-01

A Class Il malocclusion is the most frequent sagittal skeletal disharmony presenting for orthodontic treatment. A transverse interarch discrepancy ITID) may be considered as a possible functional cause of a Class 11 relationship. The purpose of the present study was to determine transverse interarch width dimensions before and after orthodontic therapy and their possible relationship with increased mandibular projection following treatment. The sample included 40 adolescent patients who were divided into two groups, one possessing and one without a transverse discrepancy. Interarch width differences (including ICWD, IPWD, IMWD, IAWD) were measured before and after treatment, and Pogonion (Pog) to Nasion (NJ perpendicular was similarly measured in each group. The differences in arch and alveolar width dimensions between the two groups (including ICWD, IPWDI, IPWDII, IMWD, IAWD) before treatment were statistically significant (p < 0.05). A comparison of Pog to N perpendicular between the two groups showed that mandibular protrusion after treatment in the transverse discrepancy group was 2.6 ± 1.3 mm, while mandibular protrusion after treatment in the group without a transverse discrepancy was 0.6 ±0.3 mm. The statistical comparison showed that the differences were significant (p < 0.01). A transverse interarch discrepancy may have a functional relationship with mandible retrusion. If a transverse discrepancy is corrected via orthodontic treatment, the mandible may spontaneously protrude.

Dentofacial transverse development in Koreans according to skeletal maturation: A cross-sectional study

PubMed Central

Hwang, Soonshin; Noh, Yoonjeong; Choi, Yoon Jeong; Chung, Chooryung; Lee, Hye Sun

2018-01-01

Objective The aim of this study was to establish the normative data of dentofacial transverse dimensions according to the skeletal maturation stage in Korean adolescents with good occlusion, assess gender differences and determine correlations between transverse variables. Methods A total of 577 Korean subjects between ages 7 to 19 years and exhibiting skeletal Class I occlusion were categorized by skeletal maturation index (SMI) of Fishman using hand-wrist radiographs. Dentofacial transverse dimensions were assessed using posteroanterior cephalograms. Independent two-sample t-tests were used to analyze differences between genders. Pearson correlation coefficient was used to determine the correlation between transverse measurements. Results Dentofacial transverse norms relevant to skeletal maturation stages were established. The average maxillomandibular width difference and ratio at growth completion was 22.16 mm and 77.01% for males; 23.70 mm and 74.06% for females, respectively. Males had greater facial, maxillary and mandibular widths compared to females at every SMI stage. The maxillary and mandibular intermolar widths showed the strongest correlation for both sexes (r = 0.826 for males, r = 0.725 for females). Conclusions Dentofacial transverse norms of Korean adolescents were established according to developmental stage. All dentofacial widths were greater in males at growth completion. Maxillary and mandibular intermolar widths were strongly correlated. This study may serve as a guideline for the assessment of dentofacial transverse growth according to skeletal maturation stage in Korean adolescents with good occlusion. PMID:29291187

Prediction of low bone mass using a combinational approach of cortical and trabecular bone measures from dental panoramic radiographs.

PubMed

Kathirvelu, D; Anburajan, M

2014-09-01

The aim of this study is to extract cortical and trabecular features of the mandible and to develop a novel combinational model of mandibular cortical thickness, trabecular bone area and age in order to predict low bone mineral density or osteoporosis from a dental panoramic radiograph. The study involved 64 south Indian women (age = 52.5 ± 12.7 years) categorised into two groups (normal and low bone mineral density) based on total femur bone mineral density. The dental panoramic radiographs were obtained by a digital scanner, and measurement of total bone mineral density at the right femur was performed by a dual-energy X-ray absorptiometry scanner. The mandibular cortical thickness and panoramic mandibular index were measured bilaterally, and the mean values were considered. The region of interest of 128 × 128 pixels around the mental foramen region was manually cropped and subjected to pre-processing, normalisation and average threshold-based segmentation to determine trabecular bone area. Multiple linear regression analyses of cortical and trabecular measures along with age were performed to develop a combinational model to classify subjects as normal and low bone mineral density. The proposed approach demonstrated strong correlation (r = 0.76; p < 0.01) against the total bone mineral density and resulted in accuracy, sensitivity and positive predictive values of 0.84, 0.92 and 0.85, respectively; the receiver operating characteristic outcomes disclosed that the area under the curve was 0.89.Our results suggest that the proposed combinational model could be useful to diagnose subjects with low bone mineral density. © IMechE 2014.

Radionuclide bone imaging in the evaluation of osseous allograft systems. Scientific report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, J.F.; Cagle, J.D.; Stevenson, J.S.

1975-02-01

Evaluation of the progress of osteogenic activity in mandibular bone grafts in dogs by a noninvasive, nondestructive radionuclide method is feasible. The method provides a meaningful sequential interpretation of osseous repair more sensitive than conventional radiography. It is presumed that accumulating hydroxyapatite is being labelled by the imaging agent technetium diphosphonate. The osseous allograft systems studied were comparable to or exceeded autografts in their repair activity in mandibular discontinuity defects as judged by radionuclide imaging. A lyophilized mandibular allograft segment augmented with autologous cancellous marrow was more active than autograft controls at 3 and 6 weeks and was the mostmore » active system studied. Allograft segments augmented with lyophilized crushed cortical allogeneic bone particles were equal to controls at 3 weeks and more active than controls at 6 weeks. Lyophilized crushed cortical allogeneic bone particles retained in a Millipore filter while not clinically stable at 6 weeks did show osteogenic activity equal to control autografts at this interval. (GRA)« less

Free Gingival Graft to Increase Keratinized Mucosa after Placing of Mandibular Fixed Implant-Supported Prosthesis

PubMed Central

Marcantonio, Elcio

2017-01-01

Insufficiently keratinized tissue can be increased surgically by free gingival grafting. The presence or reconstruction of keratinized mucosa around the implant can facilitate restorative procedure and allow the maintenance of an oral hygiene routine without irritation or discomfort to the patient. The aim of this clinical case report is to describe an oral rehabilitation procedure of an edentulous patient with absence of keratinized mucosa in the interforaminal area, using a free gingival graft associated with a mandibular fixed implant-supported prosthesis. The treatment included the manufacturing of a maxillary complete denture and a mandibular fixed implant-supported prosthesis followed by a free gingival graft to increase the width of the mandibular keratinized mucosa. Free gingival graft was obtained from the palate and grafted on the buccal side of interforaminal area. The follow-up of 02 and 12 months after mucogingival surgery showed that the free gingival graft promoted peri-implant health, hygiene, and patient comfort. Clinical Significance. The free gingival graft is an effective treatment in increasing the width of mandibular keratinized mucosa on the buccal side of the interforaminal area and provided an improvement in maintaining the health of peri-implant tissues which allows for better oral hygiene. PMID:28293441

Dental and skeletal changes in the upper and lower jaws after treatment with Schwarz appliances using cone-beam computed tomography.

PubMed

Tai, Kiyoshi; Park, Jae Hyun

2010-01-01

The purpose of this research was to use cone-beam computed tomography (CBCT) images to evaluate dental and skeletal changes in upper and lower jaws after treatment with Schwarz appliances. 28 patients with Angle Class I molar relationships and crowding were randomly divided into two groups--14 non-expanded and 14 expanded patients. 3D-Rugle CBCT software was used to measure various reference points before treatment (TO) and during the retention period of approximately 9 months after 6 to 12 month expansion (T1). Cephalometric and cast measurements were used to evaluate treatment in both groups. To test whether there were any significant differences between the control and treatment groups at TO and T1, the Mann-Whitney U-test was used. The dental arch (including tooth root apices) had expanded in the upper and lower jaws. Alveolar bone expansion of up to 2 mm apical to the cementoenamel junction (CEJ) was detected. The midpalatal sutures were separated in some cases and subsequent expansion was observed at the inner surface of the nasal cavity at the inferior turbinates. However no significant (P > 0.05) difference was observed in the inter-width of the mandibular bodies, zygomatic bones, nasal cavity in the middle turbinate region, condylar heads, or antegonial notches. In mandibular and maxillary cast measurements, arch crowding and arch perimeter showed statistically significant changes in the expansion group. The mandibular width values demonstrated no significant changes as measured from a point 2 mm apical to the CEJ whereas the maxillary width values demonstrated significant changes as measured from a point 2 mm apical to the CEJ. This study indicates that the Schwarz appliance primarily affects the dento-alveolar complex, while it has little effect on either the mandibular bodies, any associated structures including the maxillary midpalatal suture and the inter-width of the nasal cavity in the middle turbinate region. In addition, the center of rotation of the mandibular and maxillary first molar was observed apical to the root apex.

A histomorphometric analysis of the nature of the mandibular canal in the anterior molar region.

PubMed

Bertl, Kristina; Heimel, Patrick; Reich, Karoline Maria; Schwarze, Uwe Yacine; Ulm, Christian

2014-01-01

Knowledge of the position and configuration of the mandibular canal is a basic requirement before implant placement in the mandible. Radiological studies suggest a positive correlation between alveolar trabecular bone quality and mandibular canal corticalization. The aim of this study was to test this assumption histomorphometrically in the anterior molar region, which is one of the most frequent places for implantation. Fifty thin ground sections (from 28 male and 22 female cadavers) of the first molar region were investigated for trabecular bone volume and thickness and the presence of a mandibular canal wall. Trabecular bone volume was significantly higher in males (p = 0.009). Further, it correlated significantly with the presence of a canal wall (rho = 0.585, p < 0.001), indicating that a reduced trabecular bone volume is associated with a reduced amount of bone surrounding the alveolar nerve. The cranial aspects of the canal wall were present at a significantly lower frequency (64.64 %) than the buccal, lingual, or caudal sides (p < 0.006). The present study demonstrated that low trabecular bone volume correlates with only a fragmentarily present mandibular canal wall. This suggests that bone surrounding the alveolar nerve is of trabecular, not cortical, origin and possibly affected by reduction of the trabecular bone. These results imply that oral surgeons should pay particular attention to implant placement in patients with low alveolar bone quality. The cranial aspects of the mandibular canal might be only fragmentarily or even completely missing. Consequently, they hardly present resistance during implant site preparation, and the risk for nerve injury, e.g., due to post-surgery hematoma, could be increased.

[Finite element stress analysis of all-ceramic continuous crowns of the lower anterior teeth in differential shoulder thickness].

PubMed

Ouyang, Shao-bo; Wang, Jun; Zhang, Hong-bin; Liao, Lan; Zhu, Hong-shui

2014-04-01

To investigate the stress distributions under load in 3 types of all-ceramic continuous crowns of the lower anterior teeth with differential shoulder thickness. Cone-beam CT (CBCT) was used to scan the in vitro mandibular central incisors, and achieve three-dimensional finite element model of all-ceramic continuous crowns with different shoulder width by using Mimics, Abaqus software. Different load conditions were simulated based on this model to study the effect of shoulder width variation on finite element analysis of 3 kinds of different all-ceramic materials of incisors fixed continuous crowns of the mandibular. Using CBCT, Mimics10.01 software and Abaqus 6.11 software, three-dimensional finite element model of all-ceramic continuous crowns of the mandibular incisor, abutment, periodontal ligament and alveolar bone was established. Different ceramic materials and various shoulder width had minor no impact on the equivalent stress peak of periodontal membrane, as well as alveolar bone. With the same shoulder width and large area of vertical loading of 120 N, the tensile stress was the largest in In-Ceram Alumina, followed by In-Ceram Zirconia and the minimum was IPS.Empress II. Under large area loading of 120 N 45° labially, when the material was IPS.Empress II, with the shoulder width increased, the porcelain plate edge of the maximum tensile stress value increased, while the other 2 materials had no obvious change. Finite element model has good geometric similarity. In the setting range of this study, when the elastic modulus of ceramic materials is bigger, the tensile stress of the continuous crown is larger. Supported by Research Project of Department of Education, Jiangxi Province (GJJ09130).

Cortical morphology of adolescents with bipolar disorder and with schizophrenia.

PubMed

Janssen, Joost; Alemán-Gómez, Yasser; Schnack, Hugo; Balaban, Evan; Pina-Camacho, Laura; Alfaro-Almagro, Fidel; Castro-Fornieles, Josefina; Otero, Soraya; Baeza, Inmaculada; Moreno, Dolores; Bargalló, Nuria; Parellada, Mara; Arango, Celso; Desco, Manuel

2014-09-01

Recent evidence points to overlapping decreases in cortical thickness and gyrification in the frontal lobe of patients with adult-onset schizophrenia and bipolar disorder with psychotic symptoms, but it is not clear if these findings generalize to patients with a disease onset during adolescence and what may be the mechanisms underlying a decrease in gyrification. This study analyzed cortical morphology using surface-based morphometry in 92 subjects (age range 11-18 years, 52 healthy controls and 40 adolescents with early-onset first-episode psychosis diagnosed with schizophrenia (n=20) or bipolar disorder with psychotic symptoms (n=20) based on a two year clinical follow up). Average lobar cortical thickness, surface area, gyrification index (GI) and sulcal width were compared between groups, and the relationship between the GI and sulcal width was assessed in the patient group. Both patients groups showed decreased cortical thickness and increased sulcal width in the frontal cortex when compared to healthy controls. The schizophrenia subgroup also had increased sulcal width in all other lobes. In the frontal cortex of the combined patient group sulcal width was negatively correlated (r=-0.58, p<0.001) with the GI. In adolescents with schizophrenia and bipolar disorder with psychotic symptoms there is cortical thinning, decreased GI and increased sulcal width of the frontal cortex present at the time of the first psychotic episode. Decreased frontal GI is associated with the widening of the frontal sulci which may reduce sulcal surface area. These results suggest that abnormal growth (or more pronounced shrinkage during adolescence) of the frontal cortex represents a shared endophenotype for psychosis. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitation of mandibular ramus volume as a source of bone grafting.

PubMed

Verdugo, Fernando; Simonian, Krikor; Smith McDonald, Roberto; Nowzari, Hessam

2009-10-01

When alveolar atrophy impairs dental implant placement, ridge augmentation using mandibular ramus graft may be considered. In live patients, however, an accurate calculation of the amount of bone that can be safely harvested from the ramus has not been reported. The use of a software program to perform these calculations can aid in preventing surgical complications. The aim of the present study was to intra-surgically quantify the volume of the ramus bone graft that can be safely harvested in live patients, and compare it to presurgical computerized tomographic calculations. The AutoCAD software program quantified ramus bone graft in 40 consecutive patients from computerized tomographies. Direct intra-surgical measurements were recorded thereafter and compared to software data (n = 10). In these 10 patients, the bone volume was also measured at the recipient sites 6 months post-sinus augmentation. The mandibular second and third molar areas provided the thickest cortical graft averaging 2.8 +/- 0.6 mm. The thinnest bone was immediately posterior to the third molar (1.9 +/- 0.3 mm). The volume of ramus bone graft measured by AutoCAD averaged 0.8 mL (standard deviation [SD] 0.2 mL, range: 0.4-1.2 mL). The volume of bone graft measured intra-surgically averaged 2.5 mL (SD 0.4 mL, range: 1.8-3.0 mL). The difference between the two measurement methods was significant (p < 0.001). The bone volume measured 6 months post-sinus augmentation averaged 2.2 mL (SD 0.4 mL, range: 1.6-2.8 mL) with a mean loss of 0.3 mL in volume. The mandibular second molar area provided the thickest cortical graft. A cortical plate of 2.8 mm in average at combined second and third molar areas provided 2.5 mL particulated volume. The use of a design software program can improve surgical treatment planning prior to ramus bone grafting. The AutoCAD software program did not overestimate the volume of bone that can be safely harvested from the mandibular ramus.

Radiographic assessment of lower third molar eruption in different anteroposterior skeletal patterns and age-related groups.

PubMed

Jakovljevic, Aleksandar; Lazic, Emira; Soldatovic, Ivan; Nedeljkovic, Nenad; Andric, Miroslav

2015-07-01

To analyze radiographic predictors for lower third molar eruption among subjects with different anteroposterior skeletal relations and of different age groups. In total, 300 lower third molars were recorded on diagnostic digital orthopantomograms (DPTs) and lateral cephalograms (LCs). The radiographs were grouped according to sagittal intermaxillary angle (ANB), subject age, and level of lower third molar eruption. The DPT was used to analyze retromolar space, mesiodistal crown width, space/width ratio, third and second molar angulation (α, γ), third molar inclination (β), and gonion angle. The LC was used to determine ANB, angles of maxillar and mandibular prognathism (SNA, SNB), mandibular plane angle (SN/MP), and mandibular lengths. A logistic regression model was created using the statistically significant predictors. The logistic regression analysis revealed a statistically significant impact of β angle and distance between gonion and gnathion (Go-Gn) on the level of lower third molar eruption (P < .001 and P < .015, respectively). The retromolar space was significantly increased in the adult subgroup for all skeletal classes. The lower third molar impaction rate was significantly higher in the adult subgroup with the Class II (62.3%) compared with Class III subjects (31.7%; P < .013). The most favorable values of linear and angular predictors of mandibular third molar eruption were measured in Class III subjects. For valid estimation of mandibular third molar eruption, certain linear and angular measures (β angle, Go-Gn), as well as the size of the retromolar space, need to be considered.

Refining experimental dental implant testing in the Göttingen Minipig using 3D computed tomography—A morphometric study of the mandibular canal

PubMed Central

Plendl, Johanna; Hünigen, Hana; Richardson, Kenneth C.; Gemeinhardt, Ole; Niehues, Stefan M.

2017-01-01

This study reports morphometric and age-related data of the mandibular canal and the alveolar ridge of the Göttingen Minipig to avoid complications during in vivo testing of endosseus dental implants and to compare these data with the human anatomy. Using 3D computed tomography, six parameters of the mandibular canal as well as the alveolar bone height and the alveolar ridge width were measured in Göttingen Minipigs aged 12, 17 and 21 months. Our null hypothesis assumes that the age and the body mass have an influence on the parameters measured. The study found that the volume, length and depth of the mandibular canal all increase with age. The width of the canal does not change significantly with age. The body mass does not have an influence on any of the measured parameters. The increase in canal volume appears to be due to loss of deep spongy bone in the posterior premolar and molar regions. This reduces the available space for dental implantations, negatively affecting implant stability and potentially the integrity of the inferior alveolar neurovascular bundle. Dynamic anatomical changes occur until 21 months. On ethical grounds, using minipigs younger than 21 months in experimental implant dentistry is inadvisable. Paradoxically the measurements of the 12 months old pigs indicate a closer alignment of their mandibular anatomy to that of humans suggesting that they may be better models for implant studies. Given the variability in mandibular canal dimensions in similar age cohorts, the use of imaging techniques is essential for the selection of individual minipigs for dental prosthetic interventions and thus higher success rates. PMID:28910382

Comparative Evaluation of Cone-beam Computed Tomography versus Direct Surgical Measurements in the Diagnosis of Mandibular Molar Furcation Involvement

PubMed Central

Padmanabhan, Shyam; Dommy, Ahila; Guru, Sanjeela R.; Joseph, Ajesh

2017-01-01

Aim: Periodontists frequently experience inconvenience in accurate assessment and treatment of furcation areas affected by periodontal disease. Furcation involvement (FI) most commonly affects the mandibular molars. Diagnosis of furcation-involved teeth is mainly by the assessment of probing pocket depth, clinical attachment level, furcation entrance probing, and intraoral periapical radiographs. Three-dimensional imaging has provided advantage to the clinician in assessment of bone morphology. Thus, the present study aimed to compare the diagnostic efficacy of cone-beam computed tomography (CBCT) as against direct intrasurgical measurements of furcation defects in mandibular molars. Subjects and Methods: Study population included 14 patients with 25 mandibular molar furcation sites. CBCT was performed to measure height, width, and depth of furcation defects of mandibular molars with Grade II and Grade III FI. Intrasurgical measurements of the FI were assessed during periodontal flap surgery in indicated teeth which were compared with CBCT measurements. Statistical analysis was done using paired t-test and Bland–Altman plot. Results: The CBCT versus intrasurgical furcation measurements were 2.18 ± 0.86 mm and 2.30 ± 0.89 mm for furcation height, 1.87 ± 0.52 mm and 1.84 ± 0.49 mm for furcation width, and 3.81 ± 1.37 mm and 4.05 ± 1.49 mm for furcation depth, respectively. Results showed that there was no statistical significance between the measured parameters, indicating that the two methods were statistically similar. Conclusion: Accuracy of assessment of mandibular molar FI by CBCT was comparable to that of direct surgical measurements. These findings indicate that CBCT is an excellent adjunctive diagnostic tool in periodontal treatment planning. PMID:29042732

Relation of trophic changes in the central nervous system, measured by the width of cordical sulci, to the clinical course of anorexia nervosa (II).

PubMed

Nogal, Pawel; Pniewska-Siark, Barbara; Lewinski, Andrzej

2008-12-01

In patients with anorexia nervosa (AN), computer tomography (CT) scanning and/or magnetic resonance imaging (MR) are usually applied to visualise trophic changes of the brain, resulting from considerable malnutrition or general cachexia of the organism. The goal of the study was an evaluation attempt of the degree of trophic changes in the central nervous system (CNS) of girls with AN, following CT scanning of the brain, together with an analysis of selected clinical and diagnostic parameters, related to the trophic changes in question. The study involved fifty-five (55) female patients with AN. Following CT of the brain - scanning of the cortical sulci - four (4) groups of the patients were identified. The following classification of lesions was applied: Group I - width of cortical sulci < 1.5 mm - standard; Group II - the presence of cortical sulci of width < 1.5 mm and 1.5-3 mm; Group III - width of cortical sulci 1.5-3 mm; Group IV - the presence of cortical sulci of width at 1.5-3 mm and > 3 mm. We did not observe any patient with AN in whom the width of all the cortical sulci was bigger than 3 mm (Group V). In all the groups, clinical parameters, as well as routine laboratory tests and selected hormonal tests, were analysed. In the performed CT scanning of the head in patients with AN, trophic changes in the CNS (as evaluated by the width of cortical sulci) were revealed in 67.3% of the patients. Among the studied groups, statistically significant differences were found for: body weight loss (BWL), the percent of BWL (BWL%), the BWL to disease duration ratio (BWL/time) and BWL%/time, serum concentrations of potassium, calcium, glucose, total protein and urea, as well as serum concentrations of LH, E2, cortisol, FT3 and FT4. The most pronounced disturbances were observed in Group IV, while the least ones - in Group I. In CT scanning of the head, trophic changes in the CNS were observed in girls with AN, measured by the width of cortical sulci. The higher severity of trophic changes in the CNS was associated with higher BWL/time ratio, higher hypercortisolemia, more enhanced hypogonadotrophic hypogonadism, disorders in the peripheral metabolism of the thyroid hormones and with the obtained values of routine laboratory tests, indicating some tendency towards hypovolemia.

Evaluation of Mandibular Anatomy Associated With Bad Splits in Sagittal Split Ramus Osteotomy of Mandible.

PubMed

Wang, Tongyue; Han, Jeong Joon; Oh, Hee-Kyun; Park, Hong-Ju; Jung, Seunggon; Park, Yeong-Joon; Kook, Min-Suk

2016-07-01

This study aimed to identify risk factors associated with bad splits during sagittal split ramus osteotomy by using three-dimensional computed tomography. This study included 8 bad splits and 47 normal patients without bad splits. Mandibular anatomic parameters related to osteotomy line were measured. These included anteroposterior width of the ramus at level of lingula, distance between external oblique ridge and lingula, distance between sigmoid notch and inferior border of mandible, mandibular angle, distance between inferior outer surface of mandibular canal and inferior border of mandible under distal root of second molar (MCEM), buccolingual thickness of the ramus at level of lingula, and buccolingual thickness of the area just distal to first molar (BTM1) and second molar (BTM2). The incidence of bad splits in 625 sagittal split osteotomies was 1.28%. Compared with normal group, bad split group exhibited significantly thinner BTM2 and shorter sigmoid notch and inferior border of mandible (P <0.05). However, for BTM1 and buccolingual thickness of the ramus at level of lingula, there was no statistical difference between the 2 groups. Mandibular angle, anteroposterior width of the ramus at level of lingula, external oblique ridge and lingula, and MCEM were not significantly different between the groups. This study suggests that patients with shorter ramus and low thickness of the buccolingual alveolar region distal to the second molar had a higher risk of bad splits. These anatomic data may help surgeons to choose the safest surgical techniques and best osteotomy sites.

The use of titanium miniscrews for molar protraction in extraction treatment.

PubMed

Giancotti, Aldo; Greco, Mario; Mampieri, Gianluca; Arcuri, Claudio

2004-01-01

Orthodontic space closure in the mandibular arch by protraction of the mandibular second molars, after the extraction of first molars, may sometimes result in loss of incisor anchorage when using conventional orthodontic procedures. The introduction of miniscrews for immediate loading as orthodontic anchorage, has enlarged treatment possibilities. The authors illustrate their clinical experience in an adult patient treated with the extraction of mandibular first molars and the protraction of second and third molars into the extraction sites. Anchorage control was achieved with the surgical insertion of titanium miniscrews for immediate loading in the cortical bone distal to second bicuspids. Space closure was achieved by means of sliding mechanics according to Bidimensional Technique. The position of lower incisors was maintained preventing any detrimental facial effect.

Clinical importance of median mandibular flexure in oral rehabilitation: a review.

PubMed

Sivaraman, K; Chopra, A; Venkatesh, S B

2016-03-01

The mandible has a property to flex inwards around the mandibular symphysis with change in shape and decrease in mandibular arch width during opening and protrusion of the mandible. The mandibular deformation may range from a few micrometres to more than 1 mm. The movement occurs because of the contraction of lateral pterygoid muscles that pulls mandibular condyles medially and causes a sagittal movement of the posterior segments. This movement of mandible can have a profound influence on prognosis and treatment outcome for various restorative, endodontics, fixed, removable and implant-related prosthesis. The review unfolds the causes, importance and clinical implications of median mandibular flexure in oral rehabilitation. This review also highlights the appropriate preventive measures and techniques that should be adopted by clinicians to minimise the effect of flexural movement of the jaw during oral rehabilitation. This would not only help clinicians to achieve a good prosthesis with accurate fit and longevity but also maintain the health of the surrounding periodontal or periimplant gingival tissues and bone. © 2015 John Wiley & Sons Ltd.

Median mandibular flexure at different mouth opening and its relation to different facial types: A prospective clinical study

PubMed Central

Prasad, Mandava; Hussain, Mohammed Z.; Shetty, Sharath K.; Kumar, T. Ashok; Khaur, Mohit; George, Suja A.; Dalwai, Sameen

2013-01-01

Objective: To measure the arch width and Median mandibular flexure (MMF) values at relative rest and maximum jaw opening in young adults with Dolichofacial, Mesofacial, and Brachyfacial types and tested whether the variation in the facial pattern is related to the MMF values in South Indian population. Materials and Methods: This Prospective clinical study consisted of sample of 60 young adults. The subjects were grouped into 3 groups: Group 1: Brachyfacial, Group 2: Mesofacial and types, Group 3: Dolichofacial. Impressions were taken for all the 60 subjects and the casts were scanned and digitized. The intermolar width was measured for Dolichofacial, Mesofacial, and Brachyfacial subjects at relative rest (R) and maximum opening (O). Results: The statistical analysis of the observations included Descriptive and Inferential statistics. The statistical analysis was executed by means of Sigma graph pad prism software, USA Version-4. Kruskal wallis (ANOVA) followed by Dunns post hoc test was performed. Mann Whitney U-test was performed to assess the difference in MMF values between Males and Females of the three groups. The Mean (SD) Mandibular flexure in individuals with Brachyfacial type was 1.12 (0.09), Mesofacial type was 0.69 (0.21), and Dolichofacial type was 0.39 (0.08). Conclusions: The Mean intermolar width was maximum in Brachyfacial type and minimum in Dolichofacial type. MMF was maximum at the maximum mouth opening position and was maximum in individuals with Brachyfacial type. PMID:24082745

Piezosurgery for the lingual split technique in mandibular third molar removal: a suggestion.

PubMed

Pippi, Roberto; Alvaro, Roberto

2013-03-01

The lingual split technique is a surgical procedure for extraction of impacted mandibular third molar throughout a lingual approach. The main disadvantage of this technique is the high rate of temporary lingual nerve injury mainly because of the trauma induced by the lingual flap retraction. The purpose of this paper is to suggest the use of piezosurgery in performing the lingual cortical plate osteotomy of the third molar alveolar process. Surgical procedure was performed under general anesthesia, and it lasted approximately 60 minutes. After the buccal and lingual full-thickness flaps were incised and elevated, a piezosurgical device was used for osteotomy. A well-defined bony window was then removed, and it allowed the entire tooth was extracted in a lingual direction. The patient did not show any neurological postoperative complication. Lingual and inferior alveolar nerve functionality was normal before as well as after surgery. The use of piezoelectric surgery seems to be a good option in removing lower third molars when a lingual access is clearly indicated. The only disadvantage of this technique can be represented by an operating time lengthening possibly because of a lower power cut of the piezoelectric device, to the high mineralization of the mandibular cortical bone and to the use of inserts with a low degree of sharpening.

Evaluation of the alignment efficiency of nickel-titanium and copper-nickel-titanium archwires in patients undergoing orthodontic treatment over a 12-week period: A single-center, randomized controlled clinical trial.

PubMed

Aydın, Burcu; Şenışık, Neslihan Ebru; Koşkan, Özgür

2018-05-01

The aim of this trial was to compare the alignment efficiency and intermaxillary arch dimension changes of nickel-titanium (NiTi) or copper-nickel-titanium (CuNiTi) round archwires with increasing diameters applied sequentially to the mandibular arch. The initial alignment phase of fixed orthodontic treatment with NiTi or CuNiTi round archwires was studied in a randomly allocated sample of 66 patients. The NiTi group comprised 26 women, 10 men, and the CuNiTi (27℃) group comprised 20 women, 10 men. The eligibility criteria were as follows: anterior mandibular crowding of minimum 6 mm according to Little's Irregularity Index (LII), treatment requiring no extraction of premolars, 12 to 18 years of age, permanent dentition, skeletal and dental Class I malocclusion. The main outcome measure was the alignment of the mandibular anterior dentition; the secondary outcome measure was the change in mandibular dental arch dimensions during 12 weeks. Simple randomization (allocation ratio 1:1) was used in this single-blind study. LII and mandibular arch dimensions were measured on three-dimensional digital dental models at 2-week intervals. No statistically significant difference was observed between NiTi and CuNiTi according to LII ( p > 0.05). Intercanine and intermolar arch perimeters increased in the CuNiTi group ( p < 0.001). Inter-first premolar width showed a statistically significant interaction in week × diameter × application ( p < 0.05). The effects of NiTi and CuNiTi round archwires were similar in terms of their alignment efficiency. However, the intercanine and intermolar arch perimeters, and the inter-first premolar width changes differed between groups.

Mandibular bone changes in 24 years and skeletal fracture prediction.

PubMed

Jonasson, G; Sundh, V; Hakeberg, M; Hassani-Nejad, A; Lissner, L; Ahlqwist, M

2013-03-01

The objectives of the investigation were to describe changes in mandibular bone structure with aging and to compare the usefulness of cortical and trabecular bone for fracture prediction. From 1968 to 1993, 1,003 women were examined. With the help of panoramic radiographs, cortex thickness was measured and cortex was categorized as: normal, moderately, or severely eroded. The trabeculation was assessed as sparse, mixed, or dense. Visually, the mandibular compact and trabecular bone transformed gradually during the 24 years. The compact bone became more porous, the intertrabecular spaces increased, and the radiographic image of the trabeculae seemed less mineralized. Cortex thickness increased up to the age of 50 and decreased significantly thereafter. At all examinations, the sparse trabeculation group had more fractures (71-78 %) than the non-sparse group (27-31 %), whereas the severely eroded compact group showed more fractures than the less eroded groups only in 1992/1993, 24 years later. Sparse trabecular pattern was associated with future fractures both in perimenopausal and older women (relative risk (RR), 1.47-4.37) and cortical erosion in older women (RR, 1.35-1.55). RR for future fracture associated with a severely eroded cortex increased to 4.98 for cohort 1930 in 1992/1993. RR for future fracture associated with sparse trabeculation increased to 11.43 for cohort 1922 in 1992/1993. Dental radiographs contain enough information to identify women most at risk of future fracture. When observing sparse mandibular trabeculation, dentists can identify 40-69 % of women at risk for future fractures, depending on participant age at examination.

An Evaluation of Mandibular Dental and Basal Arch Dimensions in Class I and Class II Division 1 Adult Syrian Patients using Cone-beam Computed Tomography.

PubMed

Al-Hilal, Layal H; Sultan, Kinda; Hajeer, Mohammad Y; Mahmoud, Ghiath; Wanli, Abdulrahman A

2018-04-01

Aim: The aim of this study is (1) to inspect any difference in mandibular arch widths between males and females in class I and class II division 1 (class malocclusions using cone-beam computed tomography (CBCT), (2) to compare the mandibular dental and basal widths between the two groups, and (3) to investigate any possible correlation between dental and basal arch widths in both groups. Materials and methods: The CBCT images of 68 patients aged between 18 and 25 years consisted of 34 class I (17 males and 17 females) and 34 class (17 males and 17 females) who were recruited at the Department of Orthodontics, University of Damascus Dental School (Syria). Using on-demand three-dimensional (3D) on axial views, facial axis points for dental measurements and basal bone center (BBC) points for basal measurements were identified on lower canines and first molars. Dental and basal intercanine width (ICW) and intermolar width (IMW) were measured. Results: Independent t-test showed a statistically significant difference between males and females in several variables in both groups and a statistically significant difference between class I and class groups in the basal ICW for both genders and in the dental ICW for females only (p < 0.05). In class I group, Pearson's correlation coefficients between dental and basal measurements showed a strong correlation in the IMW for both genders (r > 0.73; p < 0.01) and a moderate correlation in females' ICW (r = 0.67; p < 0.01). In the class group, a moderate correlation in females' IMW (r = 0.67; p < 0.01) was found. Conclusion: Females compared with males had narrower dimensions. Class I patients had larger ICW than class II-1 patients in all measurements and had narrower IMW than class in most measurements for both genders. There were moderate-to-strong correlations between dental and basal dimensions. BBC points might be landmarks that accurately represent the basal bone arch. Clinical significance: CBCT-based assessments of dental and basal arch dimensions provide a great opportunity to accurately evaluate these aspects, to enhance clinicians' decisions regarding proper tooth movements, and to achieve good dentoalveolar intra-arch harmony. Keywords: Basal arch, Class I, Class Cone-beam computed tomography, Dental arch, Intercanine width, Intermolar width.

Protraction of mandibular second and third molars assisted by partial corticision and miniscrew anchorage.

PubMed

Mimura, Hiroshi

2013-08-01

A woman, aged 47 years 6 months, with an anterior open bite and a left-shifted mandible was treated with a mandibular right first molar extraction and without orthognathic surgery. However, her mandibular second molar did not move mesially during treatment because of the dense lamina dura; therefore, corticision was applied only on the mesial aspect of the mandibular second molar, and a miniscrew was inserted simultaneously. Corticision was introduced as a supplemental dentoalveolar surgery in orthodontic therapy to achieve accelerated tooth movement with minimal surgical intervention. In this technique, a reinforced scalpel was used as a thin chisel to separate the interproximal cortices transmucosally without a flap. This technique was applied not to accelerate tooth movement, but to protract the mandibular molars. One miniscrew was inserted on the mesiobuccal side of the mandibular right molar for protraction and intrusion. In addition, 2 miniscrews were inserted in the buccal sides of the maxillary first and second molars and the palatal side of the maxillary first molar to intrude them for correction of the mandibular shift and the cant of the occlusal plane. Excellent occlusion and correction of the anterior open bite were achieved without surgery. At the 2-year follow-up examination, the patient had a good occlusion and showed good stability with no opening of the extraction space. A partial corticision is an effective option for facilitating movement of mandibular molars. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Tooth display and lip position during spontaneous and posed smiling in adults.

PubMed

Van Der Geld, Pieter; Oosterveld, Paul; Berge, Stefaan J; Kuijpers-Jagtman, Anne M

2008-08-01

To analyze differences in tooth display, lip-line height, and smile width between the posed smiling record, traditionally produced for orthodontic diagnosis, and the spontaneous (Duchenne) smile of joy. The faces of 122 male participants were each filmed during spontaneous and posed smiling. Spontaneous smiles were elicited through the participants watching a comical movie. Maxillary and mandibular lip-line heights, tooth display, and smile width were measured using a digital videographic method for smile analysis. Paired sample t-tests were used to compare measurements of posed and spontaneous smiling. Maxillary lip-line heights during spontaneous smiling were significantly higher than during posed smiling. Compared to spontaneous smiling, tooth display in the (pre)molar area during posed smiling decreased by up to 30%, along with a significant reduction of smile width. During posed smiling, also mandibular lip-line heights changed and the teeth were more covered by the lower lip than during spontaneous smiling. Reduced lip-line heights, tooth display, and smile width on a posed smiling record can have implications for the diagnostics of lip-line height, smile arc, buccal corridors, and plane of occlusion. Spontaneous smiling records next to posed smiling records are therefore recommended for diagnostic purposes. Because of the dynamic nature of spontaneous smiling, it is proposed to switch to dynamic video recording of the smile.

Apathy is related to cortex morphology in CADASIL. A sulcal-based morphometry study.

PubMed

Jouvent, E; Reyes, S; Mangin, J-F; Roca, P; Perrot, M; Thyreau, B; Hervé, D; Dichgans, M; Chabriat, H

2011-04-26

Apathy is a debilitating symptom in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the pathophysiology of which remains poorly understood. The aim of this study was to evaluate the neuroanatomic correlates of apathy, using new MRI postprocessing methods based on the identification of cortical sulci, in a large cohort of patients with CADASIL. A total of 132 patients with genetically confirmed diagnosis were included in this prospective cohort study. Global cognitive performances were assessed by the Mattis Dementia Rating Scale (MDRS) and disability by the modified Rankin score (mRS). Apathy was defined according to standard criteria. Depth, width, and cortical thickness of 10 large sulci of the frontal lobe in each hemisphere were measured. Logistic regression modeling was used to evaluate the links between apathy and cortical thickness, depth, or width of the different sulci. All models were adjusted for age, gender, level of education, MDRS, mRS, depression, and global brain volume. Complete MRI datasets of high quality were available in 119 patients. Depth of the posterior cingulate sulcus exhibited the strongest association with apathy in fully adjusted models (right: p value = 0.0006; left: p value = 0.004). Depth and width of cortical sulci in mediofrontal and orbitofrontal areas were independently associated with apathy. By contrast, cortical thickness was not. Cortical morphology in mediofrontal and orbitofrontal areas, by contrast to cortical thickness, is strongly and independently associated with apathy. These results suggest that apathy is related to a reduction of cortical surface rather than of cortical thickness secondary to lesion accumulation in CADASIL.

Corticosteroid-induced mandibular growth retardation and palatal malformation in the ICR mouse fetus.

PubMed Central

Silbermann, M; Levitan, S

1979-01-01

Pregnant ICR mice were treated with triamcinolone hexacetonide at various stages of gestation. The mandibular ramus and its condylar cartilage were studied histologically in both viable and non-viable offspring. In addition, measurements were made of the overall height of the posterior vertical dimension of the mandible and of condylar height and width. Significant changes were noted in these parameters. Concomitantly, marked changes were observed in the various zones of the condylar cartilage. A very high incidence of cleft palate was noted in newborn and stillborn mice previously treated with triamcinolone. A possible correlation between mandibular growth retardation and palatal clefting is discussed. Images Fig. 4 Fig. 5 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 PMID:489465

COMPUTED TOMOGRAPHIC APPEARANCE OF THE TEMPOROMANDIBULAR JOINT IN 1018 ASYMPTOMATIC HORSES: A MULTI-INSTITUTION STUDY.

PubMed

Carmalt, James L; Kneissl, Sibylle; Rawlinson, Jennifer E; Zwick, Timo; Zekas, Lisa; Ohlerth, Stefanie; Bienert-Zeit, Astrid

2016-05-01

Published descriptions of nonseptic arthritis of the equine temporomandibular joint (TMJ) are rare and large studies investigating variations in the TMJ for asymptomatic horses are lacking. The objectives of this cross-sectional, retrospective, multi-institutional study were to describe anatomical variations in the TMJ detected using computed tomography (CT) in an equid population asymptomatic for TMJ disease and determine whether these variations were associated with patient signalment, reason for CT examination, or CT slice width. Medical records at eight hospitals were searched for horses that had head/neck CT scans and no clinical signs of TMJ disease. Age, breed, sex, clinical presentation, and CT slice width data were recorded. Alterations in CT contour and density of the mandibular condyles, mandibular fossae, and TMJ intra-articular discs were described for each horse. Generalized logistic regression was used to test associations between anatomical variations and horse age. A total of 1018 horses were sampled. Anatomical variations were found in TMJ CT images for 40% of horses and 29% of joints. These were dichotomous with regard to age. Horses <1 year old commonly had alterations in the shape and density of the mandibular condyle. Older horses commonly had spherical hypodensities within the mandibular condyles consistent with bone cysts; and hyperdense regions of the intra-articular disc consistent with dystrophic mineralization. Findings indicated that TMJ anatomic variations were common in CT images of younger and older horses asymptomatic for TMJ disease. Future studies are needed to more definitively characterize these CT variations using gross pathology and histopathology. © 2016 American College of Veterinary Radiology.

Radiographic study of the mandibular retromolar canal: an anatomic structure with clinical importance.

PubMed

von Arx, Thomas; Hänni, Andrea; Sendi, Pedram; Buser, Daniel; Bornstein, Michael M

2011-12-01

The retromolar canal is an anatomic structure of the mandible with clinical importance. This canal branches off from the mandibular canal behind the third molar and travels to the retromolar foramen in the retromolar fossa. The retromolar canal might conduct accessory innervation to the mandibular molars or contain an aberrant buccal nerve. Patients referred for panoramic radiography were consecutively enrolled, provided a limited cone-beam computed tomography (CBCT) scan had also been taken in the area of interest. Radiographs were retrospectively screened for the presence of a retromolar canal, and linear measurements (distance to second molar, height, width) were taken. One hundred twenty-one sides in 100 patients were evaluated (100 unilateral and 21 bilateral cases). A total of 31 retromolar canals were identified with CBCT (25.6%). Only 7 of these canals were also seen on the corresponding panoramic radiographs. The existence of a retromolar canal was not statistically related to gender or side. With regard to the linear measurements, the mean distance from the retromolar canal to the second molar was 15.16 mm (±2.39 mm), the mean height of the canal was 11.34 mm (±2.36 mm), and the mean width was 0.99 mm (±0.31 mm). This radiographic study documents a frequency of 25% for the presence of a retromolar canal. The clinician is advised to preserve this anatomic variation when performing surgery in the retromolar area and to consider additional locoregional anesthesia in the case of failed mandibular block anesthesia. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Three-dimensional photography for the evaluation of facial profiles in obstructive sleep apnoea.

PubMed

Lin, Shih-Wei; Sutherland, Kate; Liao, Yu-Fang; Cistulli, Peter A; Chuang, Li-Pang; Chou, Yu-Ting; Chang, Chih-Hao; Lee, Chung-Shu; Li, Li-Fu; Chen, Ning-Hung

2018-06-01

Craniofacial structure is an important determinant of obstructive sleep apnoea (OSA) syndrome risk. Three-dimensional stereo-photogrammetry (3dMD) is a novel technique which allows quantification of the craniofacial profile. This study compares the facial images of OSA patients captured by 3dMD to three-dimensional computed tomography (3-D CT) and two-dimensional (2-D) digital photogrammetry. Measurements were correlated with indices of OSA severity. Thirty-eight patients diagnosed with OSA were included, and digital photogrammetry, 3dMD and 3-D CT were performed. Distances, areas, angles and volumes from the images captured by three methods were analysed. Almost all measurements captured by 3dMD showed strong agreement with 3-D CT measurements. Results from 2-D digital photogrammetry showed poor agreement with 3-D CT. Mandibular width, neck perimeter size and maxillary volume measurements correlated well with the severity of OSA using all three imaging methods. Mandibular length, facial width, binocular width, neck width, cranial base triangle area, cranial base area 1 and middle cranial fossa volume correlated well with OSA severity using 3dMD and 3-D CT, but not with 2-D digital photogrammetry. 3dMD provided accurate craniofacial measurements of OSA patients, which were highly concordant with those obtained by CT, while avoiding the radiation associated with CT. © 2018 Asian Pacific Society of Respirology.

Evaluation of the accuracy of linear measurements on multi-slice and cone beam computed tomography scans to detect the mandibular canal during bilateral sagittal split osteotomy of the mandible.

PubMed

Freire-Maia, B; Machado, V deC; Valerio, C S; Custódio, A L N; Manzi, F R; Junqueira, J L C

2017-03-01

The aim of this study was to compare the accuracy of linear measurements of the distance between the mandibular cortical bone and the mandibular canal using 64-detector multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT). It was sought to evaluate the reliability of these examinations in detecting the mandibular canal for use in bilateral sagittal split osteotomy (BSSO) planning. Eight dry human mandibles were studied. Three sites, corresponding to the lingula, the angle, and the body of the mandible, were selected. After the CT scans had been obtained, the mandibles were sectioned and the bone segments measured to obtain the actual measurements. On analysis, no statistically significant difference was found between the measurements obtained through MSCT and CBCT, or when comparing the measurements from these scans with the actual measurements. It is concluded that the images obtained by CT scan, both 64-detector multi-slice and cone beam, can be used to obtain accurate linear measurements to locate the mandibular canal for preoperative planning of BSSO. The ability to correctly locate the mandibular canal during BSSO will reduce the occurrence of neurosensory disturbances in the postoperative period. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Three-Dimensional Analysis of Mandibular Angle Classification and Aesthetic Evaluation of the Lower Face in Chinese Female Adults.

PubMed

Mao, Xiaoyan; Fu, Xi; Niu, Feng; Chen, Ying; Jin, Qi; Qiao, Jia; Gui, Lai

2018-05-14

Reduction gonioplasty is very popular in East Asia. However, there has been little quantitative criteria for mandibular angle classification or aesthetics. The aim of this study was to investigate the quantitative differences of mandibular angle types and determine the morphologic features of mandibular angle in attractive women. We created a database of skull computed tomography and standardized frontal and lateral photographs of 96 Chinese female adults. Mandibular angle was classified into 3 groups, namely, extraversion, introversion, and healthy group, based on the position of gonion. We used a 5-point Likert scale to quantify attractiveness based on photographs. Those who scored 4 or higher were defined as attractive women. Three types of computed tomography measurements of the mandible were taken, including 4 distances, 4 angles, and 3 proportions. Discriminant analysis was applied to establish a mathematic model for mandibular angle aesthetics evaluation. Significant differences were observed between the different types of mandibular angle in lower facial width (Gol-Gor), mandibular angle (Co-Go-Me), and gonion divergence angle (Gol-Me-Gor) (P < 0.01). Chinese attractive women had a mandibular angle of 123.913 ± 2.989 degrees, a FH-MP of 27.033 ± 2.695 degrees, and a Go-Me/Co-Go index of 2.0. The "healthy" women had a mandibular angle of 116.402 ± 5.373 degrees, a FH-MP of 19.556 ± 5.999 degrees, and a Go-Me/Co-Go index of 1.6. The estimated Fisher linear discriminant function for the identification of attractive women was as follows: Y = -0.1516X1(Co-Go) + 0.128X2(Go-Me) + 0.04936X3(Co-Go-Me) +0.0218X4(FH-MP). Our study quantified the differences of mandibular angle types and identified the morphological features of mandibular angle in attractive Chinese female adults. Our results could assist plastic surgeons in presurgical designing of new aesthetic gonion and help to evaluate lower face aesthetics.

Thoracic pedicle classification determined by inner cortical width of pedicles on computed tomography images: its clinical significance for posterior vertebral column resection to treat rigid and severe spinal deformities-a retrospective review of cases.

PubMed

Zhang, Ying; Xie, Jingming; Wang, Yingsong; Bi, Ni; Zhao, Zhi; Li, Tao

2014-08-13

Posterior vertebral column resection (PVCR) is an effective alternative for treating rigid and severe spinal deformities. Accurate placement of pedicle screws, especially apically, is crucial. As morphologic evaluations of thoracic pedicles have not provided objective criteria, we propose a thoracic pedicle classification for treating rigid and severe spinal deformities. A consecutive series of 56 patients with severe and rigid spinal deformities who underwent PVCR at a single institution were reviewed retrospectively. Altogether, 1098 screws were inserted into thoracic pedicles at T2-T12. Based on the inner cortical width of the thoracic pedicles, the patients were divided into four groups: group 1 (0-1.0 mm), group 2 (1.1-2.0 mm), group 3 (2.1-3.0 mm), group 4 (≥3.1 mm). The proportion of screws accurately inserted in thoracic pedicles for each group was calculated. Statistical analysis was also performed regarding types of thoracic pedicles classified by Lenke et al. (SPINE 35:1836-1842, 2010) using a morphological method. There were statistically significant differences in the rates of screws inserted in thoracic pedicles between the groups (P < 0.008) except groups 3 and 4 (P > 0.008), which were then combined. The accuracies for the three new groups were 35.05%, 65.34%, and 88.32%, respectively, with statistically significant differences between the groups (P < 0.017). Rates of screws inserted in thoracic pedicles classified by Lenke et al. (SPINE 35:1836-1842, 2010) were 82.31%, 83.40%, 80.00%, and 30.28% for types A, B, C, and D, respectively. There was no statistically significant difference (P > 0.008) between these types except between type D and the other three types (P < 0.008). The inner cortical width of thoracic pedicles is the sole factor crucial for accurate placement of thoracic pedicle screws. We propose a computed tomography-based classification of the pedicle's inner cortical width: type I thoracic pedicle: absent channel, inner cortical width of 0-1 mm; type II: presence of a channel of which type IIa has an inner cortical width of 1.1-2.0 mm and type IIb a width of ≥2.1 mm. The proposed classification can help surgeons predict whether screws can be inserted into the thoracic pedicle, thus guiding instrumentation when PVCR is performed.

Large Bone Vertical Augmentation Using a Three-Dimensional Printed TCP/HA Bone Graft: A Pilot Study in Dog Mandible.

PubMed

Carrel, Jean-Pierre; Wiskott, Anselm; Scherrer, Susanne; Durual, Stéphane

2016-12-01

Osteoflux is a three-dimensional printed calcium phosphate porous structure for oral bone augmentation. It is a mechanically stable scaffold with a well-defined interconnectivity and can be readily shaped to conform to the bone bed's morphology. An animal experiment is reported whose aim was to assess the performance and safety of the scaffold in promoting vertical growth of cortical bone in the mandible. Four three-dimensional blocks (10 mm length, 5 mm width, 5 mm height) were affixed to edentulous segments of the dog's mandible and covered by a collagen membrane. During bone bed preparation, particular attention was paid not to create defects 0.5 mm or more so that the real potential of the three-dimensional block in driving vertical bone growth can be assessed. Histomorphometric analyses were performed after 8 weeks. At 8 weeks, the three-dimensional blocks led to substantial vertical bone growth up to 4.5 mm from the bone bed. Between 0 and 1 mm in height, 44% of the surface was filled with new bone, at 1 to 3 mm it was 20% to 35%, 18% at 3 to 4, and ca. 6% beyond 4 mm. New bone was evenly distributed along in mesio-distal direction and formed a new crest contour in harmony with the natural mandibular shape. After two months of healing, the three-dimensional printed blocks conducted new bone growth above its natural bed, up to 4.5 mm in a canine mandibular model. Furthermore, the new bone was evenly distributed in height and density along the block. These results are very promising and need to be further evaluated by a complete powerful study using the same model. © 2016 Wiley Periodicals, Inc.

The mandibular symphysis as a starting point for the occlusal-level reconstruction of panfacial fractures with bicondylar fractures and interruption of the maxillary and mandibular arches: report of two cases.

PubMed

Pau, Mauro; Reinbacher, Knut Ernst; Feichtinger, Matthias; Navysany, Kawe; Kärcher, Hans

2014-06-01

Panfacial fractures represent a challenge, even for experienced maxillofacial surgeons, because all references for reconstructing the facial skeleton are missing. Logical reconstructive sequencing based on a clear understanding of the correlation between projection and the widths and lengths of facial subunits should enable the surgeon to achieve correct realignment of the bony framework of the face and to prevent late deformity and functional impairment. Reconstruction is particularly challenging in patients presenting with concomitant fractures at the Le Fort I level and affecting the palate, condyles, and mandibular symphysis. In cases without bony loss and sufficient dentition, we believe that accurate fixation of the mandibular symphysis can represent the starting point of a reconstructive sequence that allows successful reconstruction at the Le Fort I level. Two patients were treated in our department by reconstruction starting in the occlusal area through repair of the mandibular symphysis. Both patients considered the postoperative facial shape and profile to be satisfactory and comparable to the pre-injury situation. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Predictors of postretention stability of mandibular dental arch dimensions in patients treated with a lip bumper during mixed dentition followed by fixed appliances.

PubMed

Raucci, Gaetana; Pachêco-Pereira, Camila; Elyasi, Maryam; d'Apuzzo, Fabrizia; Flores-Mir, Carlos; Perillo, Letizia

2017-03-01

To identify which dental and/or cephalometric variables were predictors of postretention mandibular dental arch stability in patients who underwent treatment with transpalatal arch and lip bumper during mixed dentition followed by full fixed appliances in the permanent dentition. Thirty-one patients were divided into stable and relapse groups based on the postretention presence or absence of relapse. Intercuspid, interpremolar, and intermolar widths; arch length and perimeter; crowding; and lower incisor proclination were evaluated before treatment (T0), after lip bumper treatment (T1), after fixed appliance treatment (T2), and a minimum of 3 years after removal of the full fixed appliance (T3). Logistic regression analyses were performed to evaluate the effect of changes between T0 and T1, as predictive variables, on the occurrence of relapse at T3. The model explained 53.5 % of the variance in treatment stability and correctly classified 80.6 % of the sample. Of the seven prediction variables, intermolar and interpremolar changes between T0 and T1 (P = .024 and P = .034, respectively) were statistically significant. For every millimeter of increase in intermolar and interpremolar widths there was a 1.52 and 2.70 times increase, respectively, in the odds of having stability. There was also weak evidence for the effect of sex (P = .047). The best predictors of an average 4-year postretention mandibular dental arch stability after treatment with a lip bumper followed by full fixed appliances were intermolar and interpremolar width increases during lip bumper therapy. The amount of relapse in this crowding could be considered clinically irrelevant.

Functional and morphological correlates of mandibular symphyseal form in a living human sample.

PubMed

Holton, Nathan E; Franciscus, Robert G; Ravosa, Matthew J; Southard, Thomas E

2014-03-01

Variation in recent human mandibular form is often thought to reflect differences in masticatory behavior associated with variation in food preparation and subsistence strategies. Nevertheless, while mandibular variation in some human comparisons appear to reflect differences in functional loading, other comparisons indicate that this relationship is not universal. This suggests that morphological variation in the mandible is influenced by other factors that may obscure the effects of loading on mandibular form. It is likely that highly strained mandibular regions, including the corpus, are influenced by well-established patterns of lower facial skeletal integration. As such, it is unclear to what degree mandibular form reflects localized stresses incurred during mastication vs. a larger set of correlated features that may influence bone distribution patterns. In this study, we examine the relationship between mandibular symphyseal bone distribution (i.e., second moments of area, cortical bone area) and masticatory force production (i.e., in vivo maximal bite force magnitude and estimated symphyseal bending forces) along with lower facial shape variation in a sample of n = 20 living human male subjects. Our results indicate that while some aspects of symphyseal form (e.g., wishboning resistance) are significantly correlated with estimates of symphyseal bending force magnitude, others (i.e., vertical bending resistance) are more closely tied to variation in lower facial shape. This suggests that while the symphysis reflects variation in some variables related to functional loading, the complex and multifactorial influences on symphyseal form underscores the importance of exercising caution when inferring function from the mandible especially in narrow taxonomic comparisons. Copyright © 2013 Wiley Periodicals, Inc.

Assessment of the Biomechanical Performance of 5 Plating Techniques in Fixation of Mandibular Subcondylar Fracture Using Finite Element Analysis.

PubMed

Darwich, Mhd Ayham; Albogha, Mhd Hassan; Abdelmajeed, Adnan; Darwich, Khaldoun

2016-04-01

The aim of this study was to compare the performances of 5 plating techniques for fixation of unilateral mandibular subcondylar fracture. Five titanium plating techniques for fixation of condylar fracture were analyzed using the finite element method. The modeled techniques were 1) 1 straight plate, 2) 2 parallel straight plates, 3) 2 angulated straight plates, 4) 1 trapezoidal plate, and 5) 1 square plate. Three-dimensional models were generated using patient-specific geometry for the mandible obtained from a computerized tomographic image of a healthy living man. Plates were designed and combined with the mandible and analyzed under a 500-N load. The single straight plate presented the most inferior performance; it presented maximum displacement and strain on cortical bone. The trapezoidal plate induced the least amount of strain on cortical bone and was best at resisting displacement. The trapezoidal plate is recommended for fixation of subcondylar fracture. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Cephalometric norms from posteroanterior Ricketts' cephalograms from Hispanic Americans Peruvian non adult patients.

PubMed

Pérez, Iván E; Chávez, Allison K; Ponce, Darío

2011-01-01

The purpose of the present study was to describe the posteroanterior cephalometric norm values from Hispanic Americans Peruvian non adults patients between years 2009 to 2010, identify possible differences between sexes and compare our results with similar studies in the literature. Data from posteroanterior cephalograms from 318 patients (177 females and 141 males) between 9 and 18 years old were collected from our database; mean and standard deviation were calculated for each gender and age group. Independent samples T-test found statistically significant differences between males and females results in the intermolar width, right molar to maxillae distance, nasal width, nasal height, maxillary width, mandibular width and facial width. statistically differences between sexes were found in seven from twelve transversal measurements. The norm values found in this study are similar to those reported by Ricketts'.

Effect of dexamethasone on mandibular bone biomechanics in rats during the growth phase as assessed by bending test and peripheral quantitative computerized tomography.

PubMed

Bozzini, Clarisa; Champin, Graciela; Alippi, Rosa M; Bozzini, Carlos E

2015-04-01

Long-term glucocorticoid administration to growing rats induces osteopenia and alterations in the biomechanical behavior of the bone. This study was performed to estimate the effects of dexamethasone (DTX), a synthetic steroid with predominant glucocorticoid activity, on the biomechanical properties of the mandible of rats during the growth phase, as assessed by bending test and peripheral quantitative computed tomographic (pQCT) analysis. The data obtained by the two methods will provide more precise information when analyzed together than separately. Female rats aged 23 d (n=7) received 500μg.kg-1 per day of DXT for 4 weeks. At the end of the treatment period, their body weight and body length were 51.3% and 20.6% lower, respectively, than controls. Hemimandible weight and area (an index of mandibular size) were 27.3% and 9.7% lower, respectively. The right hemimandible of each animal was subjected to a mechanical 3-point bending test. Significant weakening of the bone, as shown by a correlative impairment of strength and stiffness, was observed in experimental rats. Bone density and cross-sectional area were measured by pQCT. Cross-sectional, cortical and trabecular areas were reduced by 20% to 30% in the DTX group, as were other cortical parameters, including the bone density, mineral content and cross-sectional moment of inertia. The "bone strength index" (BSI, the product of the pQCT-assessed xCSMI and vCtBMD) was 56% lower in treated rats, which compares well with the 54% and 52% reduction observed in mandibular strength and stiffness determined through the bending test. Data suggest that the corticosteroid exerts a combined, negative action on bone geometry (mass and architecture) and volumetric bone mineral density of cortical bone, which would express independent effects on both cellular (material quality) and tissue (cross-sectional design) levels of biological organization of the skeleton in the species.

Mathematical equation for prediction of cat mandibular canal height dimension based on canine tooth width measurement.

PubMed

Santos, Miguel; Carreira, L Miguel

2016-06-01

The present study was performed in a sample of 33 cats and aimed (1) to characterise the mandible height (Mh), mandibular canal height (MCh) and the distance between the interdental alveolar margin and the mandibular canal (dIAM-MC); and (2) to develop a mathematical model for dimension prediction of MCh using the patient's age, weight (Wg) and canine tooth width at the free gingival margin level (wCGM) that was easily accessible during the oral examination. Age, sex, breed, weight, skull type and the wCGM were the recorded variables for each patient. Right and left lateral view skull radiographs were made followed by measurements of the mandible anatomical structures, taken between the third premolar distal root and the fourth premolar proximal root. Results were considered statistically significant for P values <0.05, and statistical analysis was performed using SPSS software. We observed a strong correlation only between wCGM and MCh, and a prediction mathematical model was developed to calculate the MCh, with a standard error of only 0.4 mm. Our study allows a surgeon to establish relationships between a physical parameter, such as wCGM, evaluated in an oral examination, and the mandibular canal, which is a very important anatomical structure to consider in surgical procedures. Ideally, surgeons should always plan their mandible work only after obtaining a final diagnosis achieved through the use of complementary imaging exams, such as intra- and extra-oral radiographs. Thus, this mathematical equation offers an additional tool, providing more information on the relationships between oral anatomical structures, reducing the risk of iatrogenic lesions and promoting patient safety. © ISFM and AAFP 2015.

Interspecies difference in placement of developing teeth and its relationship with cross-sectional geometry of the mandibular symphysis in four primate species including modern humans.

PubMed

Fukase, Hitoshi

2012-02-01

The form of the anthropoid mandibular symphysis has recently been addressed in association with spatial requirements for the forming anterior teeth. To evaluate potential relationships between the symphyseal shape and teeth further, the growth patterns of the symphyseal region and the positioning of the tooth crypts were examined using CT data, comparing four primate species (modern humans, chimpanzees, Japanese monkeys, and hamadryas baboons) with varied symphyseal curvature and tooth size. First, results showed that interspecies differences in overall mandibular shape including symphyseal inclination and bicanine width are consistently expressed throughout postnatal ontogeny, although local symphyseal configurations related to the superior transverse torus (STT) tended to change considerably during growth in chimpanzees. Second, the four species were found to exhibit differentiated formation positions of the incisor and canine crypts. In particular, I2 developed between I1 and C in humans with a broad bicanine space and small teeth, whereas it was positioned posterior to I1 and above C in the cercopithecines with an extremely narrow bicanine space. In chimpanzees, despite the large bicanine width, I1 and I2 grew with a large antero-posterior overlap owing to their large size. These results indicate that the dental positioning is determined in concert with the size balance of the available mandibular space and forming teeth. Finally, the positions/contours of I2 crypt were shown to correspond strongly with the STT across the taxa. This suggests that interspecies differences in symphyseal shape should be interpreted partially by the species-specific positional relationships of the developing anterior teeth. Copyright © 2011 Wiley Periodicals, Inc.

Analysis of body mass index, the mandible, and dental alveolar arch factors in prediction of mandibular third molar impaction: a pilot study.

PubMed

Akinbami, Babatunde O; Didia, Blessing C

2010-12-01

The aim of this study was to determine how some physical characteristics can be used to predict the occurrence of impacted mandibular third molars. While the concept of prophylactic removal of the asymptomatic erupting or impacted mandibular third molar has generated much controversy over the years, new theories of therapeutic surgical removal of the erupting tooth and therapeutic agenesis of the tooth bud are emerging. However, there are a few studies that address the anthropometric factors that could predict an impacted mandibular third molar. The study included Nigerian patients of both genders who were at least 16 years of age. A total of 83 subjects participated in the study; there were 44 (53 percent) females and 39 (47 percent) males. Eighty-one (97.6 percent) of the participants were between 16 and 23 years old, while 2 (2.4 percent) were between 30 and 39 years old, of which 44 (53 percent) were women and 39 (47 percent) were men. There were 38 (45.8 percent) cases of impaction and 45 (54.2 percent) cases of unimpacted third molar. The mean and standard deviation values of BMI for the two groups in males and females were 21.10±1.90, 22.40±2.70 and 22.00±2.40, 22.30±1.99 respectively, with no significant difference, p>0.05, CI 95%. The two determinant factors of impaction were mandibular length and the difference between alveolar arch length (p=0.04) and total teeth size. Both of these variables had significant inverse correlations with impaction values of p=0.04 and p=0.003, respectively. The prediction values were 59 percent for mandibular length and 81.9 percent for differences between mandibular length and teeth sizes, respectively. The synthesized prediction value by the two determinant factors is 75.6 percent.The subjects were divided into two categories: presence of impaction (Group 1) and absence of impaction (Group 2). Impaction of the mandibular third molar was assessed by clinical and radiographic evaluation. Body mass index (BMI) of each subject was determined by measuring the body weight (BW) and body height (BH), then dividing the weight of the body by the square of the height. The mandibular index (MI) was assessed by measuring the length and width of the mandible (MW). It was calculated by dividing the width of the mandible by the length of the mandible. The mandibular length (ML) consisted of the total teeth sizes of the three anterior teeth, the two premolars, and the first and second molars. These dimensions were measured with a divider/ruler and recorded. The anterior-posterior distance of the arch from the midline to the retromolar pad (alveolar arch length) also was measured. The prediction of mandibular third molar impaction was mainly dependent on two factors: the length of the mandible and the difference between arch length and total teeth size. Small mandible, small dental arch, and large teeth are risk factors that are strongly associated with the occurrence of impacted third molars.

Sella size and jaw bases - Is there a correlation???

PubMed

Neha; Mogra, Subraya; Shetty, Vorvady Surendra; Shetty, Siddarth

2016-01-01

Sella turcica is an important cephalometric structure and attempts have been made in the past to correlate its dimensions to the malocclusion. However, no study has so far compared the size of sella to the jaw bases that determine the type of malocclusion. The present study was undertaken to find out any such correlation if it exists. Lateral cephalograms of 110 adults consisting of 40 Class I, 40 Class II, and 30 Class III patients were assessed for the measurement of sella length, width, height, and area. The maxillary length, mandibular ramus height, and body length were also measured. The sella dimensions were compared among three malocclusion types by one-way ANOVA. Pearson correlation was calculated between the jaw size and sella dimensions. Furthermore, the ratio of jaw base lengths and sella area were calculated. Mean sella length, width and area were found to be greatest in Class III, followed by Class I and least in Class II though the results were not statistically significant. 3 out of 4 measured dimensions of sella, correlated significantly with mandibular ramus and body length each. However, only one dimension of sella showed significant correlation with maxilla. The mandibular ramus and body length show a nearly constant ratio to sella area (0.83-0.85, 0.64-0.65, respectively) in all the three malocclusions. Thus, mandible has a definite and better correlation to the size of sella turcica.

[Clinical effect of removable lingual arch plus auxiliary spring for dental arch expansion].

PubMed

Sun, Feng-yang; Zhang, Yu

2007-04-01

Observe the clinical effect of removable lingual arch plus auxiliary spring for convenient dental (especially mandibular) arch expansion. Seventeen patients with dental arch constriction complicated by mild dental crowding were enrolled in this study, including 9 requiring maxillary arch expansion and 8 necessitating mandibular expansion. The patients were divided to two groups at random for arch expansion with removable lingual arch plus auxiliary spring and with Quad-helix, respectively, and the effect of arch expansion was compared between the two groups. After 8 weeks of arch expansion, the average width of U4-U4 and U5-U5 in removable lingual arch group was enlarged by 2.2 mm and 3.0 mm, and that in Quad-helix group by 2.3 mm and 3.5 mm, respectively, showing no significant differences between the two groups (P>0.05). After 12 weeks of treatment, the average width of L4-L4 and L5-L5 in the former group was enlarged by 2.3 mm and 2.5 mm, respectively, significantly greater than that in the latter group (1.0 mm and 1.2 mm, P<0.05). Removable lingual arch plus auxiliary spring allows significant expansion of the middle segment of the dental arch (bicuspids), and can be more effective than Quad-helix for mandibular arch expansion.

Anterior maxillary and mandibular biotype: relationship between gingival thickness and width with respect to underlying bone thickness.

PubMed

La Rocca, Andres Pascual; Alemany, Antonio Santos; Levi, Paul; Juan, Monica Vicario; Molina, Jose Nart; Weisgold, Arnold S

2012-12-01

: Periodontal biotype is considered to be a significant factor related to successful dental treatments. The purpose of this study was to determine the relationship between gingival thickness (GT) and width with respect to the underlying bone thickness in the maxillary and mandibular anterior sextant. : Overall, 180 anterior teeth within healthy patients were assessed. GT and buccal bone thickness (BT) were measured at 3 locations: crestal/gingival margin, tooth apex, and a midpoint between the 2. In addition, the apicoincisal gingival width (GW) was recorded. Clinical and cone beam CT measurements were compared and correlated. : No statistically significant relations were observed between GT and BT measures at any of the 3 positions. The mean GT at crestal mid and apical position for the maxillary teeth was 1.01 (±0.58) mm, 1.06 (±0.48) mm, and 0.83 (±0.47) mm, respectively, and the corresponding mean BT was 1.24 (±0.90) mm, 0.81 (±0.33) mm, and 2.78 (±1.62) mm, respectively. The GW is directly related (R = 0.007; P < 0.05) to the crestal BT. : In this study, the GT is not linked to the BT. However, the GW seems to be associated with the crestal BT.

TRH regulates action potential shape in cerebral cortex pyramidal neurons.

PubMed

Rodríguez-Molina, Víctor; Patiño, Javier; Vargas, Yamili; Sánchez-Jaramillo, Edith; Joseph-Bravo, Patricia; Charli, Jean-Louis

2014-07-07

Thyrotropin releasing hormone (TRH) is a neuropeptide with a wide neural distribution and a variety of functions. It modulates neuronal electrophysiological properties, including resting membrane potential, as well as excitatory postsynaptic potential and spike frequencies. We explored, with whole-cell patch clamp, TRH effect on action potential shape in pyramidal neurons of the sensorimotor cortex. TRH reduced spike and after hyperpolarization amplitudes, and increased spike half-width. The effect varied with dose, time and cortical layer. In layer V, 0.5µM of TRH induced a small increase in spike half-width, while 1 and 5µM induced a strong but transient change in spike half-width, and amplitude; after hyperpolarization amplitude was modified at 5µM of TRH. Cortical layers III and VI neurons responded intensely to 0.5µM TRH; layer II neurons response was small. The effect of 1µM TRH on action potential shape in layer V neurons was blocked by G-protein inhibition. Inhibition of the activity of the TRH-degrading enzyme pyroglutamyl peptidase II (PPII) reproduced the effect of TRH, with enhanced spike half-width. Many cortical PPII mRNA+ cells were VGLUT1 mRNA+, and some GAD mRNA+. These data show that TRH regulates action potential shape in pyramidal cortical neurons, and are consistent with the hypothesis that PPII controls its action in this region. Copyright © 2014 Elsevier B.V. All rights reserved.

Treatment of mandibular symphyseal fracture combined with dislocated intracapsular condylar fractures.

PubMed

Xu, Xiaofeng; Shi, Jun; Xu, Bing; Dai, Jiewen; Zhang, Shilei

2015-03-01

To evaluate the treatment methods of mandibular symphyseal fracture combined with dislocated intracapsular condylar fractures (MSF&DICF) and to compare the effect of different treatment methods of condylar fractures. Twenty-eight patients with MSF&DICF were included in this study. Twenty-two sites were treated by open reduction, and all the medial condylar fragments were fixed with titanium screws; whereas the other 22 sites underwent close treatment. The surgical effect between these 2 groups was compared based on clinical examination and radiographic examination results. Seventeen of 22 condyle fractures were repositioned in the surgery group, whereas 4 of 22 condyle fractures were repositioned in the close treatment group. Statistical difference was observed between these 2 groups (P < 0.01). Functional outcomes of the patients treated in the surgical treatment group also were better than those in the close treatment group. The dislocated intracapsular condyle fractures should be treated by surgical reduction with the maintenance of the attachment of lateral pterygoid muscle, which is beneficial to repositioning the dislocated condyle to its original physiological position, to closure of the mandibular lingual gap, to restore the mandibular width.

Observer performance in diagnosing osteoporosis by dental panoramic radiographs: results from the osteoporosis screening project in dentistry (OSPD).

PubMed

Taguchi, A; Asano, A; Ohtsuka, M; Nakamoto, T; Suei, Y; Tsuda, M; Kudo, Y; Inagaki, K; Noguchi, T; Tanimoto, K; Jacobs, R; Klemetti, E; White, S C; Horner, K

2008-07-01

Mandibular cortical erosion detected on dental panoramic radiographs (DPRs) may be useful for identifying women with osteoporosis, but little is known about the variation in diagnostic efficacy of observers worldwide. The purpose of this study was to measure the accuracy in identifying women at risk for osteoporosis in a worldwide group of observers using DPRs. We constructed a website that included background information about osteoporosis screening and instructions regarding the interpretation of mandibular cortical erosion. DPRs of 100 Japanese postmenopausal women aged 50 years or older who had completed skeletal bone mineral measurements by dual energy X-ray absorptiometry were digitized at 300 dpi. These were displayed on the website and used for the evaluation of diagnostic efficacy. Sixty observers aged 25 to 66 years recruited from 16 countries participated in this study. These observers classified cortical erosion into one of three groups (none, mild to moderate, and severe) on the website via the Internet, twice with an approximately 2-week interval. The diagnostic efficacy of the Osteoporosis Self-Assessment Tool (OST), a simple clinical decision rule based on age and weight, was also calculated and compared with that of cortical erosion. The overall mean sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the 60 observers in identifying women with osteoporosis by cortical erosion on DPRs were 82.5, 46.2, 46.7, and 84.0%, respectively. Those same values by the OST index were 82.9, 43.1, 43.9, and 82.4%, respectively. The intra-observer agreement in classifying cortical erosion on DPRs was sufficient (weighted kappa values>0.6) in 36 (60%) observers. This was significantly increased in observers who specialized in oral radiology (P<0.05). In the 36 observers with sufficient intra-observer agreement, the overall mean sensitivity, specificity, PPV, and NPV in identifying women with osteoporosis by any cortical erosion were 83.5, 48.7, 48.3, and 85.7%, respectively. The mean PPV and NPV were significantly higher in the 36 observers with sufficient intra-observer agreement than in the 24 observers with insufficient intra-observer agreement. Our results reconfirm the efficacy of cortical erosion findings in identifying postmenopausal women at risk for osteoporosis, among observers with sufficient intra-observer agreement. Information gathered from radiographic examination is at least as useful as that gathered from the OST index.

Histomorphometry and cortical robusticity of the adult human femur.

PubMed

Miszkiewicz, Justyna Jolanta; Mahoney, Patrick

2018-01-13

Recent quantitative analyses of human bone microanatomy, as well as theoretical models that propose bone microstructure and gross anatomical associations, have started to reveal insights into biological links that may facilitate remodeling processes. However, relationships between bone size and the underlying cortical bone histology remain largely unexplored. The goal of this study is to determine the extent to which static indicators of bone remodeling and vascularity, measured using histomorphometric techniques, relate to femoral midshaft cortical width and robusticity. Using previously published and new quantitative data from 450 adult human male (n = 233) and female (n = 217) femora, we determine if these aspects of femoral size relate to bone microanatomy. Scaling relationships are explored and interpreted within the context of tissue form and function. Analyses revealed that the area and diameter of Haversian canals and secondary osteons, and densities of secondary osteons and osteocyte lacunae from the sub-periosteal region of the posterior midshaft femur cortex were significantly, but not consistently, associated with femoral size. Cortical width and bone robusticity were correlated with osteocyte lacunae density and scaled with positive allometry. Diameter and area of osteons and Haversian canals decreased as the width of cortex and bone robusticity increased, revealing a negative allometric relationship. These results indicate that microscopic products of cortical bone remodeling and vascularity are linked to femur size. Allometric relationships between more robust human femora with thicker cortical bone and histological products of bone remodeling correspond with principles of bone functional adaptation. Future studies may benefit from exploring scaling relationships between bone histomorphometric data and measurements of bone macrostructure.

Strength of titanium intramedullary implant versus miniplate fixation of mandibular condyle fractures.

PubMed

Frake, Paul C; Howell, Rebecca J; Joshi, Arjun S

2012-07-01

To test the strength of internal fixation of mandibular condyle fractures repaired with titanium miniplates versus titanium intramedullary implants. Prospective laboratory experimentation in urethane mandible models and human cadaveric mandibles. Materials testing laboratory at an academic medical center. Osteotomies of the mandibular condyle were created in 40 urethane hemimandible models and 24 human cadaveric specimens. Half of the samples in each group were repaired with traditional miniplates, and the other half were repaired with intramedullary titanium implants. Anteroposterior and mediolateral loads were applied to the samples, and the displacement was measured with reference to the applied force. Titanium intramedullary implants demonstrated statistically significant improved strength and stiffness versus miniplates in the urethane model experimental groups. Despite frequent plastic deformation and mechanical failures of the miniplates, a 1.6-mm-diameter titanium intramedullary pin did not mechanically fail in any of the cases. Intramedullary implantation failures were due to secondary fracture of the adjacent cortical bone or experimental design limitations including rotation of the smooth pin implant. Mechanical implant failures that were encountered with miniplate fixation were not seen with titanium intramedullary implants. These intramedullary implants provide stronger and more rigid fixation of mandibular condyle fractures than miniplates in this in vitro model.

The Comprehensive AOCMF Classification System: Mandible Fractures-Level 3 Tutorial

PubMed Central

Cornelius, Carl-Peter; Audigé, Laurent; Kunz, Christoph; Rudderman, Randal; Buitrago-Téllez, Carlos H.; Frodel, John; Prein, Joachim

2014-01-01

This tutorial outlines the details of the AOCMF image-based classification system for fractures of the mandibular arch (i.e. the non-condylar mandible) at the precision level 3. It is the logical expansion of the fracture allocation to topographic mandibular sites outlined in level 2, and is based on three-dimensional (3D) imaging techniques/computed tomography (CT)/cone beam CT). Level 3 allows an anatomical description of the individual conditions of the mandibular arch such as the preinjury dental state and the degree of alveolar atrophy. Trauma sequelae are then addressed: (1) tooth injuries and periodontal trauma, (2) fracture involvement of the alveolar process, (3) the degree of fracture fragmentation in three categories (none, minor, and major), and (4) the presence of bone loss. The grading of fragmentation needs a 3D evaluation of the fracture area, allowing visualization of the outer and inner mandibular cortices. To document these fracture features beyond topography the alphanumeric codes are supplied with distinctive appendices. This level 3 tutorial is accompanied by a brief survey of the peculiarities of the edentulous atrophic mandible. Illustrations and a few case examples serve as instruction and reference to improve the understanding and application of the presented features. PMID:25489389

[Assessment tools in early detection of osteoporosis in dentistry].

PubMed

Knezović Zlatarić, Dubravka; Pandurić, Josip; Korsić, Mirko; Dodig, Damir

2007-03-01

Osteoporosis, one of the major skeletal diseases in older age, is characterised by low bone mass and microarchitectural deterioration with a resulting increase in bone fragility and hence susceptibility to fracture. In this review we analyse the systemic and local factors associated with oral bone mass loss. Systemic factors most often correlated with the oral bone mass loss include osteoporosis, renal diseases, hormonal disorders, diet and the impact of different drugs on the bony structure. Chronic periodontal disease, early loss of teeth or the effect of inadequate prosthodontic appliance on the residual ridge are the local factors associated with mandibular bone loss. Different assessment tools for the assessment of mandibular oral bone loss have been proposed, such as DXA absorptiometry, quantitative computed tomography, intraoral microdensitometry, SCORE index and the assessment of the thickness and quality of the mandibular inferior cortical border. Qualitative and quantitative assessment of the mandibular bony structure is of great importance in all fields of dentistry - from periodontology to endodontics and prosthodontics, especially in dental implantology. It is important to make the correct indication prior to dental implant therapy, and taking into account the systemic and local factors mentioned above, assess both the actual quality and quantity of the mandible.

Femoral neck BMD is a strong predictor of hip fracture susceptibility in elderly men and women because it detects cortical bone instability: the Rotterdam Study.

PubMed

Rivadeneira, Fernando; Zillikens, M Carola; De Laet, Chris Edh; Hofman, Albert; Uitterlinden, André G; Beck, Thomas J; Pols, Huibert Ap

2007-11-01

We studied HSA measurements in relation to hip fracture risk in 4,806 individuals (2,740 women). Hip fractures (n = 147) occurred at the same absolute levels of bone instability in both sexes. Cortical instability (propensity of thinner cortices in wide diameters to buckle) explains why hip fracture risk at different BMD levels is the same across sexes. Despite the sexual dimorphism of bone, hip fracture risk is very similar in men and women at the same absolute BMD. We aimed to elucidate the main structural properties of bone that underlie the measured BMD and that ultimately determines the risk of hip fracture in elderly men and women. This study is part of the Rotterdam Study (a large prospective population-based cohort) and included 147 incident hip fracture cases in 4,806 participants with DXA-derived hip structural analysis (mean follow-up, 8.6 yr). Indices compared in relation to fracture included neck width, cortical thickness, section modulus (an index of bending strength), and buckling ratio (an index of cortical bone instability). We used a mathematical model to calculate the hip fracture distribution by femoral neck BMD, BMC, bone area, and hip structure analysis (HSA) parameters (cortical thickness, section modulus narrow neck width, and buckling ratio) and compared it with prospective data from the Rotterdam Study. In the prospective data, hip fracture cases in both sexes had lower BMD, thinner cortices, greater bone width, lower strength, and higher instability at baseline. In fractured individuals, men had an average BMD that was 0.09 g/cm(2) higher than women (p < 0.00001), whereas no significant difference in buckling ratios was seen. Modeled fracture distribution by BMD and buckling ratio levels were in concordance to the prospective data and showed that hip fractures seem to occur at the same absolute levels of bone instability (buckling ratio) in both men and women. No significant differences were observed between the areas under the ROC curves of BMD (0.8146 in women and 0.8048 in men) and the buckling ratio (0.8161 in women and 0.7759 in men). The buckling ratio (an index of bone instability) portrays in both sexes the critical balance between cortical thickness and bone width. Our findings suggest that extreme thinning of cortices in expanded bones plays a key role on local susceptibility to fracture. Even though the buckling ratio does not offer additional predictive value, these findings improve our understanding of why low BMD is a good predictor of fragility fractures.

Regional Variation of Bone Tissue Properties at the Human Mandibular Condyle

PubMed Central

Kim, Do-Gyoon; Jeong, Yong-Hoon; Kosel, Erin; Agnew, Amanda M.; McComb, David W.; Bodnyk, Kyle; Hart, Richard T.; Kim, Min Kyung; Han, Sang Yeun; Johnston, William M.

2015-01-01

The temporomandibular joint (TMJ) bears different types of static and dynamic loading during occlusion and mastication. As such, characteristics of mandibular condylar bone tissue play an important role in determining the mechanical stability of the TMJ under the macro-level loading. Thus, the objective of this study was to examine regional variation of the elastic, plastic, and viscoelastic mechanical properties of human mandibular condylar bone tissue using nanoindentation. Cortical and trabecular bone were dissected from mandibular condyles of human cadavers (9 males, 54 to 96 years). These specimens were scanned using microcomputed tomography to obtain bone tissue mineral distribution. Then, nanoindentation was conducted on the surface of the same specimens in hydration. Plastic hardness (H) at a peak load, viscoelastic creep (Creep/Pmax), viscosity (η), and tangent delta (tan δ) during a 30 second hold period, and elastic modulus (E) during unloading were obtained by a cycle of indentation at the same site of bone tissue. The tissue mineral and nanoindentation parameters were analyzed for the periosteal and endosteal cortex, and trabecular bone regions of the mandibular condyle. The more mineralized periosteal cortex had higher mean values of elastic modulus, plastic hardness, and viscosity but lower viscoelastic creep and tan δ than the less mineralized trabecular bone of the mandibular condyle. These characteristics of bone tissue suggest that the periosteal cortex tissue may have more effective properties to resist elastic, plastic, and viscoelastic deformation under static loading, and the trabecular bone tissue to absorb and dissipate time-dependent viscoelastic loading energy at the TMJ during static occlusion and dynamic mastication. PMID:25913634

Cortical bone stress distribution in mandibles with different configurations restored with prefabricated bar-prosthesis protocol: a three-dimensional finite-element analysis.

PubMed

de Almeida, Erika Oliveira; Rocha, Eduardo Passos; Assunção, Wirley Gonçalves; Júnior, Amílcar Chagas Freitas; Anchieta, Rodolfo Bruniera

2011-01-01

To evaluate stress distribution in different horizontal mandibular arch formats restored by protocol-type prostheses using three-dimensional finite element analysis (3D-FEA). A representative model (M) of a completely edentulous mandible restored with a prefabricated bar using four interforaminal implants was created using SolidWorks 2010 software (Inovart, São Paulo, Brazil) and analyzed by Ansys Workbench 10.0 (Swanson Analysis Inc., Houston, PA) to obtain the stress fields. Three mandibular arch sizes were considered for analysis, regular (M), small (MS), and large (ML). Three unilateral posterior loads (L) (150 N) were used: perpendicular to the prefabricated bar (L1); 30° oblique in a buccolingual direction (L2); 30° oblique in a lingual-buccal direction (L3). The maximum and minimum principal stresses (σ(max), σ(min)), the equivalent von Mises (σ(vM)), and the maximum principal strain (σ(max) ) were obtained for type I (M.I) and type II (M.II) cortical bones. Tensile stress was more evident than compression stress in type I and II bone; however, type II bone showed lower stress values. The L2 condition showed highest values for all parameters (σ(vM), σ(max), σ(min), ɛ(max)). The σ(vM) was highest for the large and small mandibular arches. The large arch model had a higher influence on σ(max) values than did the other formats, mainly for type I bone. Vertical and buccolingual loads showed considerable influence on both σ(max) and σ(min) stresses. © 2010 by The American College of Prosthodontists.

Effect of the masseter muscle injection of botulinum toxin A on the mandibular bone growth of developmental rats.

PubMed

Seok, Hyun; Kim, Seong-Gon; Kim, Min-Keun; Jang, Insan; Ahn, Janghoon

2018-12-01

The objective of this study was to evaluate the influence of masticatory muscle injection of botulinum toxin type A (BTX-A) on the growth of the mandibular bone in vivo. Eleven Sprague-Dawley rats were used, and BTX-A ( n  = 6) or saline ( n  = 5) was injected at 13 days of age. All injections were given to the right masseter muscle, and the BTX-A dose was 0.5 units. All of the rats were euthanized at 60 days of age. The skulls of the rats were separated and fixed with 10% formalin for micro-computed tomography (micro-CT) analysis. The anthropometric analysis found that the ramus heights and bigonial widths of the BTX-A-injected group were significantly smaller than those of the saline-injected group ( P  < 0.05), and the mandibular plane angle of the BTX-A-injected group was significantly greater than in the saline-injected group ( P  < 0.001). In the BTX-A-injected group, the ramus heights II and III and the mandibular plane angles I and II showed significant differences between the injected and non-injected sides ( P  < 0.05). The BTX-A-injected side of the mandible in the masseter group showed significantly lower mandibular bone growth compared with the non-injected side. BTX-A injection into the masseter muscle influences mandibular bone growth.

[Bone graft reconstruction for posterior mandibular segment using the formwork technique].

PubMed

Pascual, D; Roig, R; Chossegros, C

2014-04-01

Pre-implant bone graft in posterior mandibular segments is difficult because of masticatory and lingual mechanical constraints, because of the limited bone vascularization, and because of the difficulty to cover it with the mucosa. The formwork technique is especially well adapted to this topography. The recipient site is abraded with a drill. Grooves are created to receive and stabilize the grafts. The bone grafts were harvested from the ramus. The thinned cortices are assembled in a formwork and synthesized by mini-plates. The gaps are filled by bone powder collected during bone harvesting. The bone volume reconstructed with the formwork technique allows anchoring implants more than 8mm long. The proximity of the inferior alveolar nerve does not contra indicate this technique. The formwork size and its positioning on the alveolar crest can be adapted to prosthetic requirements by using osteosynthesis plates. The lateral implant walls are supported by the formwork cortices; the implant apex is anchored on the native alveolar crest. The primary stability of implants is high, and the torque is important. The ramus harvesting decreases operative risks. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Comparison between rapid and mixed maxillary expansion through an assessment of arch changes on dental casts.

PubMed

Grassia, Vincenzo; d'Apuzzo, Fabrizia; Jamilian, Abdolreza; Femiano, Felice; Favero, Lorenzo; Perillo, Letizia

2015-01-01

Aim of this retrospective observational study was to compare upper and lower dental changes in patients treated with Rapid Maxillary Expansion (RME) and Mixed Maxillary Expansion (MME), assessed by dental cast analysis. Treatment groups consisted of 42 patients: the RME group (n = 21) consisted of 13 female and 8 male subjects with the mean age of 8.8 years ± 1.37 at T0 and 9.6 years ± 1.45 at T1; the MME group (n = 21) consisted of 12 female and 9 male patients with a mean age of 8.9 years ± 2.34 at T0 and 10.5 years ± 2.08 at T1. The upper and lower arch analysis was performed on four dental bilateral landmarks, on upper and lower casts; also upper and lower arch depths were measured. The groups were compared using independent sample t-test to estimate dental changes in upper and lower arches. Before expansion treatment (T0), the groups were similar for all examined variables (p>0.05). In both RME and MME group, significant increments in all the variables for maxillary and mandibular arch widths were observed after treatment. No significant differences in maxillary and mandibular arch depths were observed at the end of treatment in both groups. An evaluation of the changes after RME and MME (T1) showed statistically significant differences in mandibular arch depth (p<0.001) and maxillary intercanine widths (p<0.05). Differences in maxillary arch depth and arch width measurements were not significant. RME and MME can be considered two effective treatment options to improve transverse arch dimensions and gain space in the dental arches. A greater lower arch expansion was observed in the MME group, which might be attributed to the "lip bumper effects" observed in the MME protocol.

Morphological assessment of the mandibular canal trajectory in edentate subjects.

PubMed

Nimigean, Victor; Sîrbu, Valentin Daniel; Nimigean, Vanda Roxana; Bădiţă, Daniela Gabriela; Poll, Alexandru; Moraru, Simona Andreea; Păun, Diana Loreta

2018-01-01

The mandibular canal and its content represent the vital structure, which can complicate dentoalveolar surgical procedures in the posterior region of the mandible. The purpose of the present study was to determine the path the mandibular canal takes in relation to the horizontal and the vertical anatomical reference planes in edentate subjects, in order to minimize the risk of affecting its neurovascular content during various oral surgery procedures. Morphometric evaluations were performed on 12 dried fully edentulous human mandibles and on cone-beam computed tomography (CBCT) cross-sectional images of the mandible, from 20 patients with either partial or complete edentulism. Both methods were utilized, in three target areas (corresponding to the second premolar, to the first molar and to the second molar regions), in order to measure the distance between the mandibular canal and the following reference points: (i) the lateral (buccal) surface of the mandible (MC-BS distance); (ii) the medial (lingual) surface of the mandible (MC-LS distance); (iii) the alveolar surface of the mandible (MC-AS distance). The results were statistically processed in Stata MP/13 software package using analysis of variance (ANOVA) test. The mandibular canal crossed the trabecular bone from the posterior towards the anterior, and from the lingual towards the buccal, reaching the premolar region, distal to the mental foramen, where it was located in the centre of the trabecular bone, main topographic pattern encountered in 27 (84.37%) of the cases. In five (15.63%) of the cases, in the premolar region, the mandibular canal was located near the buccal cortical plate. The mandibular canal descended from the second molar region towards the premolar region, main topographic pattern found in 28 (87.5%) of the cases. In four (12.5%) cases, the mandibular canal had a descending trajectory in the molar regions and it took a slightly ascending course in the premolar region. According to the results, the second molar region represents the highest risk area in the accidental injury to the content of the mandibular canal, during various oral surgery procedures.

Prevention of neurological injuries during mandibular third molar surgery: technical notes

PubMed Central

La Monaca, Gerardo; Vozza, Iole; Giardino, Rita; Annibali, Susanna; Pranno, Nicola; Cristalli, Maria Paola

2017-01-01

Summary Surgery to the mandibular third molar is common, and injuries to the inferior alveolar nerve and the lingual nerve are well-recognized complications of this procedure. The aim of these technical notes is to describe operative measures for reducing neurological complications during mandibular third molar surgery. The following procedure should be used to prevent damage to the inferior alveolar nerve: a well-designed mucoperiosteal flap, to obtain appropriate access to the surgical area; a conservative ostectomy on the distal and distal-lingual side; tooth sectioning, to facilitate its removal by decreasing the retention zones; tooth dislocation in the path of withdrawal imposed by the curvature of the root apex; and careful socket debridement, when the roots of the extracted tooth are in intimate contact with the mandibular canal. To prevent injury to the lingual nerve, it is important (I) to assess the integrity of the mandibular inner cortex and exclude the presence of fenestration, which could cause the dislocation of the tooth or its fragment into the sublingual or submandibular space; (II) to avoid inappropriate or excessive dislocation proceedings, in order to prevent lingual cortex fracture; (III) to perform horizontal mesial-distal crown sectioning of the lingually inclined tooth; (IV) to protect the lingual flap with a retractor showing the cortical ridge; and (V) to pass the suture not too apically and from the inner side in a buccal-lingual direction in the retromolar area. PMID:29299188

Relationship between mandibular condyle and angle fractures and the presence of mandibular third molars.

PubMed

Mah, Deuk-Hyun; Kim, Su-Gwan; Moon, Seong-Yong; Oh, Ji-Su; You, Jae-Seek

2015-02-01

We retrospectively evaluated the impact of mandibular third molars on the occurrence of angle and condyle fractures. This was a retrospective investigation using patient records and radiographs. The sample set consisted of 440 patients with mandibular fractures. Eruption space, depth and angulation of the third molar were measured. Of the 144 angle fracture patients, 130 patients had third molars and 14 patients did not. The ratio of angle fractures when a third molar was present (1.26 : 1) was greater than when no third molar was present (0.19 : 1; odds ratio, 6.58; P<0.001). Of the 141 condyle fractures patients, the third molar was present in 84 patients and absent in 57 patients. The ratio of condyle fractures when a third molar was present (0.56 : 1) was lower than when no third molar was present (1.90 : 1; odds ratio, 0.30; P<0.001). The increased ratio of angle fractures with third molars and the ratio of condyle fractures without a third molar were statistically significant. The occurrence of angle and condyle fractures was more affected by the continuity of the cortical bone at the angle than by the depth of a third molar. These results demonstrate that a third molar can be a determining factor in angle and condyle fractures.

Variations in the buccal-lingual alveolar bone thickness of impacted mandibular third molar: our classification and treatment perspectives

PubMed Central

Ge, Jing; Zheng, Jia-Wei; Yang, Chi; Qian, Wen-Tao

2016-01-01

Selecting either buccal or lingual approach for the mandibular third molar surgical extraction has been an intense debate for years. The aim of this observational retrospective study was to classify the molar based on the proximity to the external cortical bone, and analyze the position of inferior alveolar canal (IAC) of each type. Cone-beam CT (CBCT) data of 110 deeply impacted mandibular third molars from 91 consecutive patients were analyzed. A new classification based on the mean deduction value (MD) of buccal-lingual alveolar bone thickness was proposed: MD≥1 mm was classified as buccal position, 1 mm>MD>−1 mm was classified as central position, MD≤−1 mm was classified as lingual position. The study samples were distributed as: buccal position (1.8%) in 2 subjects, central position (10.9%) in 12 and lingual position (87.3%) in 96. Ninety-six molars (87.3%) contacted the IAC. The buccal and inferior IAC course were the most common types in impacted third molar, especially in lingually positioned ones. Our study suggested that amongst deeply impacted mandibular third molars, lingual position occupies the largest proportion, followed by the central, and then the buccal type. PMID:26759181

Wound ballistics of the pig mandibular angle: a preliminary finite element analysis and experimental study.

PubMed

Chen, Yubin; Miao, Yingyun; Xu, Chuan; Zhang, Gang; Lei, Tao; Tan, Yinghui

2010-04-19

To study wound ballistics of the mandibular angle, a combined hexahedral-tetrahedral finite element (FE) model of the pig mandible was developed to simulate ballistic impact. An experimental study was carried out by measuring impact load parameters from 14 fresh pig mandibles that were shot at the mandibular angle by a standard 7.62 mm M43 bullet. FE analysis was executed through the LS-DYNA code under impact loads similar to those obtained from the experimental study. The resulting residual velocity, the transferred energy from the bullet to the mandible, and the surface area of the entrance wound had no statistical differences between the FE simulation and the experimental study. However, the mean surface area of the exit wounds in the experimental study was significantly larger than that in the simulation. According to the FE analysis, the stress concentrated zones were mainly located at the region of impact, condylar neck, coronoid process and mandibular body. The simulation results also indicated that trabecular bone had less stress concentration and a lower speed of stress propagation compared with cortical bone. The FE model is appropriate and conforms to the basic principles of wound ballistics. This modeling system will be helpful for further investigations of the biomechanical mechanisms of wound ballistics. Copyright 2009 Elsevier Ltd. All rights reserved.

Three-dimensional finite element analysis of the deformation of the human mandible: a preliminary study from the perspective of orthodontic mini-implant stability

PubMed Central

Baek, Sun-Hye; Cha, Hyun-Suk; Cha, Jung-Yul; Moon, Yoon-Shik

2012-01-01

Objective The aims of this study were to investigate mandibular deformation under clenching and to estimate its effect on the stability of orthodontic mini-implants (OMI). Methods Three finite element models were constructed using computed tomography (CT) images of 3 adults with different mandibular plane angles (A, low; B, average; and C, high). An OMI was placed between #45 and #46 in each model. Mandibular deformation under premolar and molar clenching was simulated. Comparisons were made between peri-orthodontic mini-implant compressive strain (POMI-CSTN) under clenching and orthodontic traction forces (150 g and 200 g). Results Three models with different mandibular plane angles demonstrated different functional deformation characteristics. The compressive strains around the OMI were distributed mesiodistally rather than occlusogingivally. In model A, the maximum POMI-CSTN under clenching was observed at the mesial aspect of #46 (1,401.75 microstrain [µE]), and similar maximum POMI-CSTN was observed under a traction force of 150 g (1,415 µE). Conclusions The maximum POMI-CSTN developed by clenching failed to exceed the normally allowed compressive cortical bone strains; however, additional orthodontic traction force to the OMI may increase POMI-CSTN to compromise OMI stability. PMID:23112947

Characteristic findings on panoramic radiography and cone-beam CT to predict paresthesia after extraction of impacted third molar.

PubMed

Harada, Nana; Beloor Vasudeva, Subash; Matsuda, Yukiko; Seki, Kenji; Kapila, Rishabh; Ishikawa, Noboru; Okano, Tomohiro; Sano, Tsukasa

2015-01-01

The purpose of this study was to compare findings on the relationship between impacted molar roots and the mandibular canal in panoramic and three-dimensional cone-beam CT (CBCT) images to identify those that indicated risk of postoperative paresthesia. The relationship between impacted molars and the mandibular canal was first classified using panoramic images. Only patients in whom the molar roots were either in contact with or superimposed on the canal were evaluated using CBCT. Of 466 patients examined using both panoramic and CBCT images, 280 underwent surgical extraction of an impacted molar, and 15 of these (5%) reported postoperative paresthesia. The spatial relationship between the impacted third molar root and the mandibular canal was determined by examining para-sagittal sections (lingual, buccal, inter-radicular, inferior, and combinations) obtained from the canal to the molar root and establishing the proximity of the canal to the molar root (in contact with or without loss of the cortical border and separate). The results revealed that darkening of the roots with interruption of the mandibular canal on panoramic radiographs and the inter-radicular position of the canal in CBCT images were characteristic findings indicative of risk of postoperative paresthesia. These results suggest that careful surgical intervention is required in patients with the above characteristics.

Relationship between masticatory function and internal structure of the mandible based on computed tomography findings.

PubMed

Sato, Hidemasa; Kawamura, Akira; Yamaguchi, Masaru; Kasai, Kazutaka

2005-12-01

The purposes of this study were to investigate bone mineral density as a part of bone construction in human skulls and to examine the relationship between dentofacial morphology and masticatory function by using computed tomography (CT) findings. Changes in bone mineral density in the mandible because of loss of masticatory function were tested in rats by experimentally producing an environment that inhibited mastication by the molars. Data for the human study were obtained from 27 modern male Japanese skulls (mean age, 28 years) from the University of Tokyo. Cortical bone thickness (CBT) and CT value (CV) were measured by each CT scan of the first and molars. For the animal study, a metal cap was inserted between the maxillary and mandibular incisors to prevent the molars from biting in 6-week-old male Wistar rats. The rats were killed after 2, 4, or 6 weeks, and bone mineral density was measured in cancellous and cortical bone equivalent to the first molar region by using peripheral quantitative computed tomography. In the human skull study, significant negative correlations were observed between CV in the regions of the buccal side of the second molar and the angle between the Frankfort horizontal and mandibular planes. Significant negative correlations were also observed between the gonial angle and CV in the buccal and basal sides. In the animal study, cancellous bone mineral density began to decline 4 weeks after the start of the experiment in the masticatory hypofunction group compared with the control group. By week 6, cancellous bone density had declined by 11.6% on the buccal side, 16.7% on the lingual side, 12.3% at the bifurcation of the root, and 38.1% at the root apex. Cortical bone density declined by 8% to 12% on the lingual side. The results support our hypothesis that a functional adaptive response by the mandible to mechanical stress resulting from mastication occurs not only in the muscle insertion area, but also in mandibular alveolar bone in the molar region.

Do mandibular cross-sectional properties and dental microwear give similar dietary signals?

PubMed

Organ, Jason M; Ruff, Christopher B; Teaford, Mark F; Nisbett, Richard A

2006-08-01

Previous animal experimental work evaluating the effects of dietary consistency on mastication was generally limited to studies of either mandibular structure or rates and types of tooth wear. Control groups fed hard diets (HD) consistently exhibited increased cortical remodeling and/or bone strength when compared to groups fed soft diets (SD). Results of tooth-wear studies showed faster rates of tooth wear in HD animals. This study evaluates the effects of dietary differences on both mandibular structural morphology and postcanine dental microwear in the same animals. We examined mandibles and dentitions from eight miniature swine, raised from 4 weeks to 9 months of age on HD and SD (n = 4, each group). Mandibular structural properties were calculated from peripheral quantitative computed tomography slices at the dp3-dp4 and dp4-M1 junctions. Dental microwear analysis was performed on mandibular lingual crushing facets of dp4 and M1, using photomicrographs of high-resolution casts taken at 500x magnification in a scanning electron microscope. Our results suggest that between the dp3-dp4 contact, HD animals have mandibles that are stronger and more rigid mediolaterally than SD animals. At the dp4-M1 contact, HD animals have mandibles that are stronger and more rigid mediolaterally, dorsoventrally, and in torsion than SD animals. Dental microwear results indicate that SD pigs have higher incidences of pitting and more overall microwear features on their premolars than do HD pigs, yet there are no significant differences in molar microwear morphology between the dietary groups. Near-significant correlations exist between pit size and dorsoventral bending strength, but only for HD pigs. These results suggest that dietary consistency significantly affects both mandibular structure and dental microwear, yet direct correlations between the two are complicated by a number of factors.

Accidental injury of the inferior alveolar nerve due to the extrusion of calcium hydroxide in endodontic treatment: a case report

PubMed Central

2016-01-01

During clinical endodontic treatment, we often find radiopaque filling material beyond the root apex. Accidental extrusion of calcium hydroxide could cause the injury of inferior alveolar nerve, such as paresthesia or continuous inflammatory response. This case report presents the extrusion of calcium hydroxide and treatment procedures including surgical intervention. A 48 yr old female patient experienced Calcipex II extrusion in to the inferior alveolar canal on left mandibular area during endodontic treatment. After completion of endodontic treatment on left mandibular first molar, surgical intervention was planned under general anesthesia. After cortical bone osteotomy and debridement, neuroma resection and neurorrhaphy was performed, and prognosis was observed. But no improvement in sensory nerve was seen following surgical intervention after 20 mon. A clinician should be aware of extrusion of intracanal medicaments and the possibility of damage on inferior alveolar canal. Injectable type of calcium hydroxide should be applied with care for preventing nerve injury. The alternative delivery method such as lentulo spiral was suggested on the posterior mandibular molar. PMID:26877992

Feasibility of cone beam computed tomography radiomorphometric analysis and fractal dimension in assessment of postmenopausal osteoporosis in correlation with dual X-ray absorptiometry.

PubMed

Mostafa, Raghdaa A; Arnout, Eman A; Abo El-Fotouh, Mona M

The aim of the present study was to assess the feasibility of using mandibular CBCT radiomorphometric indices and box-counting fractal dimension (FD) to detect osteoporosis in post-menopausal females, compare them with the healthy control group and to correlate the findings with the bone mineral density measured by dual X-ray absorptiometry (DXA). This study consisted of 50 post-menopausal females, with age ranging from 55 to 70 years. Based on their DXA results, they were classified into osteoporotic and control groups. Mandibular CBCT radiomorphomertic indices and FD analysis were measured. Significant differences were found for the CT cortical index scores (CTCI), CT mental index (CTMI) and CT mandibular index (CTI) between the control and osteoporotic groups. The control group showed higher mean values than the osteoporotic group. For FD values, no significant differences were found between the two groups. CBCT radiomorphometric indices could be used as an adjuvant tool to refer patients at risk of osteoporosis for further assessment.

Actinomycotic osteomyelitis of the mandible: an unusual case.

PubMed

Figueiredo, Leonardo Morais Godoy; Trindade, Soraya Castro; Sarmento, Viviane Almeida; de Oliveira, Thaís Feitosa Leitão; Muniz, Wilson Rodrigo; Valente, Rômulo Oliveira de Hollanda

2013-12-01

Actinomycotic osteomyelitis is an infection in soft tissues and/or bones, being associated with trauma or a previous nonspecific infection. This article presents an unusual case of mandibular osteomyelitis caused by Actinomyces. A 19-year-old male patient was referred for endodontic treatment of the lower right first molar about 16 months ago and removal of lower right third molar approximately 3 years before. The panoramic radiography showed change in bone density in the region of ill-defined mandibular angle boundaries, and the computed tomography (CT) showed mixed density image in the mandibular angle, with discreet expansion of cortical vestibular and lingual. Biopsy was performed, and content was aspirated in small quantity and purulent tissue fragments were sent to anatomical-pathological examination. The collected purulent secretion was colored for cytopathologic study, which showed infection by Actinomyces. In this case, the causative agent was Actinomyces, which makes it even more unusual. The origin of the microorganism has not been clearly established; however, the diagnosis allowed long-term treatment with antibiotics, which has resulted in the resolution of the case.

A morphometric analysis of the superior cervical ganglion and its surrounding structures.

PubMed

Fazliogullari, Zeliha; Kilic, Cenk; Karabulut, Ahmet Kagan; Yazar, Fatih

2016-04-01

The aim of this cadaveric study was to detect the superior cervical ganglion (SCG) in a topographic manner according to vertebrae and to determine the relationship between the vertebrae, mandibular angle and longus colli muscle through morphometric analysis. The present study was performed on 40 SCG of 20 human cadavers (16 males, 4 females). The level of the SCG was determined based on the vertebrae. Ganglion length, width and thickness were detected. Distance to the adjacent vertebra, the mandibular angle and medial side of the longus colli muscle were measured. The results were evaluated statistically. The SCG existing in all cadavers was detected at the C2 vertebra level in 34 cadavers and at the C3 vertebra level in 6 cadavers. The average length, width and thickness of the SCG were 15.18 ± 1.12, 4.62 ± 0.25, and 1.83 ± 0.10 mm, respectively. No statistically significant difference was detected in terms of the distances between the ganglion and anterior tubercle of transverse processes of the vertebrae as well as the mandibular angle on either side. The distance between the SCG and the medial edge of the longus colli muscle was significantly greater on the left side in both men (p < 0.001) and women (p < 0.01). Recognition of morphometric characteristics of the SCG and detection of its location according to adjacent formations may serve as a guide for nerve blockage studies and help surgeons to preserve the ganglion in both anterior and anterolateral cervical approaches.

The evaluation of MCI, MI, PMI and GT on both genders with different age and dental status.

PubMed

Bozdag, G; Sener, S

2015-01-01

The aim of this study was to measure the mandibular cortical index (MCI), mental index (MI), panoramic mandibular index (PMI) and cortical bone thickness in the zone of the gonial angle (GT) in panoramic radiographies from a large sample of males and females and to determine how they relate to patients' age, gender and dental status. 910 panoramic radiographs were obtained and grouped into age, dental status and gender. The MCI, MI, PMI and GT were analysed. Remarkable differences were observed for MCI and GT regarding gender, age groups and dental status on both sides (p < 0.05). While age and dental status had an effect on the MI and PMI in females, dental status had an effect on the MI and PMI in males (p < 0.05). Also, gender had an effect on the MI and PMI (p < 0.05). The effects of age and tooth loss are different in females and males. In females, the harmful effects of tooth loss and age are more prominent according to the PMI and MI measurements. The effects of age and tooth loss in the GT and MCI measurements are similar, and these indices can be accepted as more reliable in studies including both genders.

The evaluation of MCI, MI, PMI and GT on both genders with different age and dental status

PubMed Central

Sener, S

2015-01-01

Objectives: The aim of this study was to measure the mandibular cortical index (MCI), mental index (MI), panoramic mandibular index (PMI) and cortical bone thickness in the zone of the gonial angle (GT) in panoramic radiographies from a large sample of males and females and to determine how they relate to patients' age, gender and dental status. Methods: 910 panoramic radiographs were obtained and grouped into age, dental status and gender. The MCI, MI, PMI and GT were analysed. Results: Remarkable differences were observed for MCI and GT regarding gender, age groups and dental status on both sides (p < 0.05). While age and dental status had an effect on the MI and PMI in females, dental status had an effect on the MI and PMI in males (p < 0.05). Also, gender had an effect on the MI and PMI (p < 0.05). Conclusions: The effects of age and tooth loss are different in females and males. In females, the harmful effects of tooth loss and age are more prominent according to the PMI and MI measurements. The effects of age and tooth loss in the GT and MCI measurements are similar, and these indices can be accepted as more reliable in studies including both genders. PMID:26133366

Alteration of maxillary and mandibular growth of adult patients with unoperated isolated cleft palate.

PubMed

Yang, Yunqiang; Wu, Yeke; Gu, Yifei; Yang, Qijian; Shi, Bing; Zheng, Qian; Wang, Yan

2013-07-01

The objective of this study was to investigate the effects of cleft palate itself on the growth of maxilla and mandible. Fifty-two adult female patients with unoperated isolated cleft palate and 52 adult female individuals with normal occlusion were included in our study. Computer software was used for lateral cephalometry measurement. Manual measurement was performed for dental cast measurements, and sample t test analysis was applied to analyze the differences between the 2 groups using SPSS 17.0. The sella-nasion-subspinale point angle, subspinale-nasion-supramentale point angle, and maxillary arch length of the cleft group were significantly smaller than those of the control group (P < 0.01). Both maxillary and mandibular posterior dental arch widths of the cleft group were significantly larger compared with the control group (P < 0.01), whereas the sella-nasion-supramentale point angle, mandible arch length, palate height, and palate shelf inclination did not differ between the 2 groups. The measurements did not differ between the submucosal cleft and the overt cleft patients. Cleft palate itself has adverse effects on the maxilla growth with shorter maxillary arch length and wider posterior dental arch width.

Three-dimensional computer-assisted study model analysis of long-term oral-appliance wear. Part 2. Side effects of oral appliances in obstructive sleep apnea patients.

PubMed

Chen, Hui; Lowe, Alan A; de Almeida, Fernanda Riberiro; Fleetham, John A; Wang, Bangkang

2008-09-01

Oral appliances (OAs) are widely prescribed for the treatment of obstructive sleep apnea (OSA). The occlusal changes that occur after long term OA treatment have not been well described based on detailed computerized three-dimensional (3D) assessment. Seventy patients with OSA (mean age, 50.0 years) who had been treated with an OA were identified for this study. A MicroScribe-3DX dental study model analysis system was used to make 3D measurements on baseline and follow-up (88.4 +/- 26.7 months) study models. The following dental measurements showed significant changes (P <0.05) with long-term use of an OA: mandibular arch width increased more than maxillary arch width, crowding decreased in both arches, the curve of Spee became flat in the premolar area, the mandibular canine to second molar segment moved forward in relation to the maxillary arch, the bite opened and the overjet decreased except in some molar areas. A variety of occlusal changes occur with long-term OA treatment for OSA. The changes could be regarded as either adverse or beneficial depending upon the baseline characteristics.

Three-dimensional dental arch changes of patients submitted to orthodontic-surgical treatment for correction of Class II malocclusion

PubMed Central

Peixoto, Adriano Porto; Pinto, Ary dos Santos; Garib, Daniela Gamba; Gonçalves, João Roberto

2014-01-01

Introduction This study assessed the three-dimensional changes in the dental arch of patients submitted to orthodontic-surgical treatment for correction of Class II malocclusions at three different periods. Methods Landmarks previously identified on upper and lower dental casts were digitized on a three-dimensional digitizer MicroScribe-3DX and stored in Excel worksheets in order to assess the width, length and depth of patient's dental arches. Results During orthodontic preparation, the maxillary and mandibular transverse dimensions measured at the premolar regions were increased and maintained throughout the follow-up period. Intercanine width was increased only in the upper arch during orthodontic preparation. Maxillary arch length was reduced during orthodontic finalization, only. Upper and lower arch depths were stable in the study periods. Differences between centroid and gingival changes suggested that upper and lower arch premolars buccaly proclined during the pre-surgical period. Conclusions Maxillary and mandibular dental arches presented transverse expansion at premolar regions during preoperative orthodontic preparation, with a tendency towards buccal tipping. The transverse dimensions were not altered after surgery. No sagittal or vertical changes were observed during the follow-up periods. PMID:25279524

Three-dimensional dental arch changes of patients submitted to orthodontic-surgical treatment for correction of Class II malocclusion.

PubMed

Peixoto, Adriano Porto; dos Santos Pinto, Ary; Garib, Daniela Gamba; Gonçalves, João Roberto

2014-01-01

This study assessed the three-dimensional changes in the dental arch of patients submitted to orthodontic-surgical treatment for correction of Class II malocclusions at three different periods. Landmarks previously identified on upper and lower dental casts were digitized on a three-dimensional digitizer MicroScribe-3DX and stored in Excel worksheets in order to assess the width, length and depth of patient's dental arches. During orthodontic preparation, the maxillary and mandibular transverse dimensions measured at the premolar regions were increased and maintained throughout the follow-up period. Intercanine width was increased only in the upper arch during orthodontic preparation. Maxillary arch length was reduced during orthodontic finalization, only. Upper and lower arch depths were stable in the study periods. Differences between changes in centroid and gingival points suggested that upper and lower premolars buccaly proclined during the pre-surgical period. Maxillary and mandibular dental arches presented transverse expansion at premolar regions during preoperative orthodontic preparation, with a tendency towards buccal tipping. The transverse dimensions were not altered after surgery. No sagittal or vertical changes were observed during the follow-up periods.

Combined radiogrammetry and texture analysis for early diagnosis of osteoporosis using Indian and Swiss data.

PubMed

Areeckal, Anu Shaju; Kamath, Jagannath; Zawadynski, Sophie; Kocher, Michel; S, Sumam David

2018-05-26

Osteoporosis is a bone disorder characterized by bone loss and decreased bone strength. The most widely used technique for detection of osteoporosis is the measurement of bone mineral density (BMD) using dual energy X-ray absorptiometry (DXA). But DXA scans are expensive and not widely available in low-income economies. In this paper, we propose a low cost pre-screening tool for the detection of low bone mass, using cortical radiogrammetry of third metacarpal bone and trabecular texture analysis of distal radius from hand and wrist radiographs. An automatic segmentation algorithm to automatically locate and segment the third metacarpal bone and distal radius region of interest (ROI) is proposed. Cortical measurements such as combined cortical thickness (CCT), cortical area (CA), percent cortical area (PCA) and Barnett Nordin index (BNI) were taken from the shaft of third metacarpal bone. Texture analysis of trabecular network at the distal radius was performed using features obtained from histogram, gray level Co-occurrence matrix (GLCM) and morphological gradient method (MGM). The significant cortical and texture features were selected using independent sample t-test and used to train classifiers to classify healthy subjects and people with low bone mass. The proposed pre-screening tool was validated on two ethnic groups, Indian sample population and Swiss sample population. Data of 134 subjects from Indian sample population and 65 subjects from Swiss sample population were analysed. The proposed automatic segmentation approach shows a detection accuracy of 86% in detecting the third metacarpal bone shaft and 90% in accurately locating the distal radius ROI. Comparison of the automatic radiogrammetry to the ground truth provided by experts show a mean absolute error of 0.04 mm for cortical width of healthy group, 0.12 mm for cortical width of low bone mass group, 0.22 mm for medullary width of healthy group, and 0.26 mm for medullary width of low bone mass group. Independent sample t-test was used to select the most discriminant features, to be used as input for training the classifiers. Pearson correlation analysis of the extracted features with DXA-BMD of lumbar spine (DXA-LS) shows significantly high correlation values. Classifiers were trained with the most significant features in the Indian and Swiss sample data. Weighted KNN classifier shows the best test accuracy of 78% for Indian sample data and 100% for Swiss sample data. Hence, combined automatic radiogrammetry and texture analysis is shown to be an effective low cost pre-screening tool for early diagnosis of osteoporosis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Relationship between mandibular condyle and angle fractures and the presence of mandibular third molars

PubMed Central

Mah, Deuk-Hyun; Moon, Seong-Yong; Oh, Ji-Su; You, Jae-Seek

2015-01-01

Objectives We retrospectively evaluated the impact of mandibular third molars on the occurrence of angle and condyle fractures. Materials and Methods This was a retrospective investigation using patient records and radiographs. The sample set consisted of 440 patients with mandibular fractures. Eruption space, depth and angulation of the third molar were measured. Results Of the 144 angle fracture patients, 130 patients had third molars and 14 patients did not. The ratio of angle fractures when a third molar was present (1.26 : 1) was greater than when no third molar was present (0.19 : 1; odds ratio, 6.58; P<0.001). Of the 141 condyle fractures patients, the third molar was present in 84 patients and absent in 57 patients. The ratio of condyle fractures when a third molar was present (0.56 : 1) was lower than when no third molar was present (1.90 : 1; odds ratio, 0.30; P<0.001). Conclusion The increased ratio of angle fractures with third molars and the ratio of condyle fractures without a third molar were statistically significant. The occurrence of angle and condyle fractures was more affected by the continuity of the cortical bone at the angle than by the depth of a third molar. These results demonstrate that a third molar can be a determining factor in angle and condyle fractures. PMID:25741462

Birth Order and Maternal Age for Reported Cases of Severe Prenatal Cortical Hyperostosis (Caffey–Silverman Disease)

PubMed

Engel, Rolf R; Cifuentes, Raul F

2017-07-01

The spectrum of prenatal cortical hyperostosis includes a mild phenotype that typically presents after 35 weeks of gestation, and a severe form that presents earlier. The skeletal and systemic manifestations of the severe phenotype remain unexplained. A review of reported cases indicates that older mothers and firstborn infants are overrepresented. This combination suggests decreased fertility. Fourteen years after the birth of the present case, his mother presented with renal failure from multiple myeloma raising the possibility that a maternal antibody may play a role in the etiology of severe prenatal Caffey disease. The present case report is also intended to alert clinicians to potential difficulties with tracheal intubation secondary to micrognathia from mandibular involvement during a critical growth period.

Evaluation of the Transverse Displacement of the Proximal Segment After Bilateral Sagittal Split Ramus Osteotomy With Different Lingual Split Patterns and Advancement Amounts Using the Finite Element Method.

PubMed

Dai, Zhi; Hou, Min; Ma, Wen; Song, Da-Li; Zhang, Chun-Xiang; Zhou, Wei-Yuan

2016-11-01

To evaluate transverse displacement of the proximal segment after bilateral sagittal split ramus osteotomy (BSSO) advancement with different lingual split patterns and advancement amounts and to determine the influential factors related to mandibular width. A 3-dimensional finite element model of the mandible including the temporomandibular joint was created for a presurgical simulation and for BSSO with lingual split patterns I (T1; Hunsuck split) and II (T2; Obwegeser split). The mandible was advanced 3 mm (A3) and 8 mm (A8) and fixated with a conventional titanium plate. Ansys software was used to measure the linear distances of the interproximal segments and to analyze the transverse displacement distribution of proximal segments after applying the load of masticatory muscle force groups. After surgical simulation, T1A3, T1A8, T2A3, and T2A8 showed increased transverse widths (mean, 2.99, 4.70, 2.36, and 4.42 mm, respectively). For transverse augmentation, there was a statistically significant difference between the 2 different mandibular advancement amounts in T1 and in T2 (P ≤ .000), but no significant differences was observed between T1 and T2 (P ≥ .058). The maximum transverse displacement distribution in the proximal segment was measured around the gonial area, and the early contact area was found near the border between the horizontal and sagittal osteotomy lines. Transverse displacements of proximal segments occur after BSSO advancement with T1 and T2 and transverse augmentation has statistically meaningful effects depending on the amount of advancement; however, no differences in transverse augmentation between T1 and T2 were identified. The fulcrum caused by the early contact between the proximal and distal segments could be an influential factor related to mandibular width. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Systematic study of the effects of stimulus parameters and stimulus location on afterdischarges elicited by electrical stimulation in the rat.

PubMed

Shigeto, Hiroshi; Boongird, Atthaporn; Baker, Kenneth; Kellinghaus, Christoph; Najm, Imad; Lüders, Hans

2013-03-01

Electrical brain stimulation is used in a variety of clinical situations, including cortical mapping for epilepsy surgery, cortical stimulation therapy to terminate seizure activity in the cortex, and in deep brain stimulation therapy. However, the effects of stimulus parameters are not fully understood. In this study, we systematically tested the impact of various stimulation parameters on the generation of motor symptoms and afterdischarges (ADs). Focal electrical stimulation was delivered at subdural cortical, intracortical, and hippocampal sites in a rat model. The effects of stimulus parameter on the generation of motor symptoms and on the occurrence of ADs were examined. The effect of stimulus irregularity was tested using random or regular 50Hz stimulation through subdural electrodes. Hippocampal stimulation produced ADs at lower thresholds than neocortical stimulation. Hippocampal stimulation also produced significantly longer ADs. Both in hippocampal and cortical stimulation, when the total current was kept constant with changing pulse width, the threshold for motor symptom or AD was lowest between 50 and 100Hz and higher at both low and high frequencies. However, if the pulse width was fixed, the threshold did not increase above 100Hz and it apparently continued to decrease through 800Hz even if the difference did not reach statistical significance. There was no significant difference between random and regular stimulation. Overall, these results indicate that electrode location and several stimulus parameters including frequency, pulse width, and total electricity are important in electrical stimulation to produce motor symptoms and ADs. Copyright © 2012 Elsevier B.V. All rights reserved.

Thirty-two-year follow-up study of Herbst therapy: a biometric dental cast analysis.

PubMed

Pancherz, Hans; Bjerklin, Krister; Lindskog-Stokland, Birgitta; Hansen, Ken

2014-01-01

The aim of this study was to analyze the very long-term effects of Herbst treatment on tooth position and occlusion. Fourteen patients from a sample of 22 with Class II Division 1 malocclusions consecutively treated with the banded Herbst appliance were reexamined 32 years after therapy. Dental casts were analyzed from before (T1) and after (T2) treatment, and at 6 years (T3) and 32 years (T4) after treatment. Minor changes in maxillary and mandibular dental arch perimeters and arch widths were seen during treatment (T1-T2) and posttreatment (T2-T4). Mandibular incisor irregularity remained, on average, unchanged from T1 to T2 but increased continuously during the 32-year follow-up period (T2-T4). Class II molar and canine relationships were normalized in most patients from T1 to T2. During the early posttreatment period (T2-T3), there was a minor relapse; during the late posttreatment period (T3-T4), molar and canine relationships remained, on average, unchanged. Overjet and overbite were reduced to normal values in all subjects during treatment (T1-T2). After treatment (T2-T4), overjet remained, on average, unchanged, but overbite increased insignificantly. Thirty-two years after Herbst therapy, overall, acceptable long-term results were seen. Stability was found in 64% of the patients for sagittal molar relationships, in 14% for sagittal canine relationships, in 86% for overjet, and in 86% for overbite. A Class II relapse seemed to be caused by an unstable interdigitation of the occluding teeth, a persisting oral habit, or an insufficient retention regimen after treatment. Most posttreatment changes occurred during the first 6 years after treatment. After the age of 20 years, only minor changes were noted. Long-term posttreatment changes in maxillary and mandibular dental arch perimeters and widths as well as in mandibular incisor irregularity seemed to be independent of treatment and a result of physiologic dentoskeletal changes throughout adulthood. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Inferior alveolar nerve cutting; legal liability versus desired patient outcomes.

PubMed

Kim, Soung Min; Lee, Jong Ho

2017-10-01

Mandibular angle reduction or reduction genioplasty is a routine well-known facial contouring surgery that reduces the width of the lower face resulting in an oval shaped face. During the intraoral resection of the mandibular angle or chin using an oscillating saw, unexpected peripheral nerve damage including inferior alveolar nerve (IAN) damage could occur. This study analyzed cases of damaged IANs during facial contouring surgery, and asked what the basic standard of care in these medical litigation-involved cases should be. We retrospectively reviewed a total of 28 patients with IAN damage after mandibular contouring from August 2008 to July 2015. Most of the patients did not have an antipathy to medical staff because they wanted their faces to be ovoid shaped. We summarized three representative cases according to each patient's perceptions and different operation procedures under the approvement by the Institutional Review Board of Seoul National University. Most of the patients did not want to receive any further operations not due to fear of an operation but because of the changes in their facial appearance. Thus, their fear may be due to a desire for a better perfect outcome, and to avoid unsolicited patient complaints related litigation. This article analyzed representative IAN cutting cases that occurred during mandibular contouring esthetic surgery and evaluated a questionnaire on the standard of care for the desired patient outcomes and the specialized surgeon's position with respect to legal liability.

Birth Order and Maternal Age for Reported Cases of Severe Prenatal Cortical Hyperostosis (Caffey–Silverman Disease)

PubMed Central

Engel, Rolf R.; Cifuentes, Raul F.

2017-01-01

The spectrum of prenatal cortical hyperostosis includes a mild phenotype that typically presents after 35 weeks of gestation, and a severe form that presents earlier. The skeletal and systemic manifestations of the severe phenotype remain unexplained. A review of reported cases indicates that older mothers and firstborn infants are overrepresented. This combination suggests decreased fertility. Fourteen years after the birth of the present case, his mother presented with renal failure from multiple myeloma raising the possibility that a maternal antibody may play a role in the etiology of severe prenatal Caffey disease. The present case report is also intended to alert clinicians to potential difficulties with tracheal intubation secondary to micrognathia from mandibular involvement during a critical growth period. PMID:29142783

Correlations between physical properties of jawbone and dental implant initial stability.

PubMed

Seong, Wook-Jin; Kim, Uk-Kyu; Swift, James Q; Hodges, James S; Ko, Ching-Chang

2009-05-01

There is confusion in the literature about how physical properties of bone vary between maxillary and mandibular regions and which physical properties affect initial implant stability. The purpose of this study was to determine correlations between physical properties of bone and initial implant stability, and to determine how physical properties and initial stability vary among regions of jawbone. Four pairs of edentulous maxillae and mandibles were retrieved from fresh human cadavers. Six implants per pair were placed in different anatomical regions (maxillary anterior, right and left maxillary posterior, mandibular anterior, right and left mandibular posterior). Immediately after surgery, initial implant stability was measured with a resonance frequency device and a tapping device. Implant surgeries and initial stability measurements were performed within 72 hours of death. Elastic modulus (EM) and hardness were measured using nano-indentation. Composite apparent density (cAD) was measured using Archimedes' principle. Bone-implant contact percentage and cortical bone thickness were recorded histomorphometrically. Mixed linear models and univariate-correlation analyses were used (alpha=.05). Generally, mandibular bone had higher initial implant stability and physical properties than maxillary bone. Initial implant stability was higher in the anterior region than in the posterior. EM was higher in the posterior region than in the anterior; the reverse was true for cAD. Of the properties evaluated, cAD had the highest correlation with initial implant stability (r=0.82). Both physical properties of bone and initial implant stability differed between regions of jawbone.

Autogenous teeth used for bone grafting: a comparison with traditional grafting materials.

PubMed

Kim, Young-Kyun; Kim, Su-Gwan; Yun, Pil-Young; Yeo, In-Sung; Jin, Seung-Chan; Oh, Ji-Su; Kim, Heung-Joong; Yu, Sun-Kyoung; Lee, Sook-Young; Kim, Jae-Sung; Um, In-Woong; Jeong, Mi-Ae; Kim, Gyung-Wook

2014-01-01

This study evaluated the surface structures and physicochemical characteristics of a novel autogenous tooth bone graft material currently in clinical use. The material's surface structure was compared with a variety of other bone graft materials via scanning electron microscope (SEM). The crystalline structure of the autogenous tooth bone graft material from the crown (AutoBT crown) and root (AutoBT root), xenograft (BioOss), alloplastic material (MBCP), allograft (ICB), and autogenous mandibular cortical bone were compared using x-ray diffraction (XRD) analysis. The solubility of each material was measured with the Ca/P dissolution test. The results of the SEM analysis showed that the pattern associated with AutoBT was similar to that from autogenous cortical bones. In the XRD analysis, AutoBT root and allograft showed a low crystalline structure similar to that of autogenous cortical bones. In the CaP dissolution test, the amount of calcium and phosphorus dissolution in AutoBT was significant from the beginning, while displaying a pattern similar to that of autogenous cortical bones. In conclusion, autogenous tooth bone graft materials can be considered to have physicochemical characteristics similar to those of autogenous bones. Copyright © 2014 Elsevier Inc. All rights reserved.

Linking contemporary high resolution magnetic resonance imaging to the von Economo legacy: A study on the comparison of MRI cortical thickness and histological measurements of cortical structure.

PubMed

Scholtens, Lianne H; de Reus, Marcel A; van den Heuvel, Martijn P

2015-08-01

The cerebral cortex is a distinctive part of the mammalian nervous system, displaying a spatial variety in cyto-, chemico-, and myelinoarchitecture. As part of a rich history of histological findings, pioneering anatomists von Economo and Koskinas provided detailed mappings on the cellular structure of the human cortex, reporting on quantitative aspects of cytoarchitecture of cortical areas. Current day investigations into the structure of human cortex have embraced technological advances in Magnetic Resonance Imaging (MRI) to assess macroscale thickness and organization of the cortical mantle in vivo. However, direct comparisons between current day MRI estimates and the quantitative measurements of early anatomists have been limited. Here, we report on a simple, but nevertheless important cross-analysis between the histological reports of von Economo and Koskinas on variation in thickness of the cortical mantle and MRI derived measurements of cortical thickness. We translated the von Economo cortical atlas to a subdivision of the commonly used Desikan-Killiany atlas (as part of the FreeSurfer Software package and a commonly used parcellation atlas in studies examining MRI cortical thickness). Next, values of "width of the cortical mantle" as provided by the measurements of von Economo and Koskinas were correlated to cortical thickness measurements derived from high-resolution anatomical MRI T1 data of 200+ subjects of the Human Connectome Project (HCP). Cross-correlation revealed a significant association between group-averaged MRI measurements of cortical thickness and histological recordings (r = 0.54, P < 0.001). Further validating such a correlation, we manually segmented the von Economo parcellation atlas on the standardized Colin27 brain dataset and applied the obtained three-dimensional von Economo segmentation atlas to the T1 data of each of the HCP subjects. Highly consistent with our findings for the mapping to the Desikan-Killiany regions, cross-correlation between in vivo MRI cortical thickness and von Economo histology-derived values of cortical mantle width revealed a strong positive association (r = 0.62, P < 0.001). Linking today's state-of-the-art T1-weighted imaging to early histological examinations our findings indicate that MRI technology is a valid method for in vivo assessment of thickness of human cortex. © 2015 Wiley Periodicals, Inc.

Dissecting the actin cortex density and membrane-cortex distance in living cells by super-resolution microscopy

NASA Astrophysics Data System (ADS)

Clausen, M. P.; Colin-York, H.; Schneider, F.; Eggeling, C.; Fritzsche, M.

2017-02-01

Nanoscale spacing between the plasma membrane and the underlying cortical actin cytoskeleton profoundly modulates cellular morphology, mechanics, and function. Measuring this distance has been a key challenge in cell biology. Current methods for dissecting the nanoscale spacing either limit themselves to complex survey design using fixed samples or rely on diffraction-limited fluorescence imaging whose spatial resolution is insufficient to quantify distances on the nanoscale. Using dual-color super-resolution STED (stimulated-emission-depletion) microscopy, we here overcome this challenge and accurately measure the density distribution of the cortical actin cytoskeleton and the distance between the actin cortex and the membrane in live Jurkat T-cells. We found an asymmetric cortical actin density distribution with a mean width of 230 (+105/-125) nm. The spatial distances measured between the maximum density peaks of the cortex and the membrane were bi-modally distributed with mean values of 50  ±  15 nm and 120  ±  40 nm, respectively. Taken together with the finite width of the cortex, our results suggest that in some regions the cortical actin is closer than 10 nm to the membrane and a maximum of 20 nm in others.

Three-dimensional tomographic mapping related to primary stability and structural miniscrew characteristics.

PubMed

Silvestrini Biavati, A; Tecco, S; Migliorati, M; Festa, F; Panza, G; Marzo, G; Gherlone, E; Tetè, S

2011-05-01

To evaluate the maxilla, mandible, and cortical plates on computerized tomographic (CT) scans to achieve accurate three-dimensional bone thickness measurements. We selected the CT scans of 25 subjects (among 102), aged 18-58 years (10 men, 15 women), with nearly complete dentition. We performed interradicular and bucco-lingual (including cortical plate thickness) measurements in dental areas distal to the canines in both alveolar arches, at three levels (5, 8, and 11 mm) from the alveolar ridge. The mean thicknesses of the cortical plates in the maxilla were 1.10 mm buccally and 1.27 mm on the palatal side (p < 0.05). In the mandible, cortical plates were 2.23 mm buccally and 2.02 mm lingually. Mandibular buccal and lingual cortical plates became thicker distally in the second and third molar areas. There was considerable variation in cortical thickness (from 0.25 to 5.50 mm). Based on interradicular distances, only 13% of measured sites in the maxilla were suitable for miniscrew insertion (≥3.3 mm), but 63% of sites were suitable in the mandible. This study showed considerable individual variation in bone thickness. Our data suggested that the palatal/lingual side may provide greater primary stability for miniscrews. The palatal area, between the second upper bicuspid and the first molar, appeared to be the most suitable area for tapered 7- to 9-mm miniscrews, starting at 1.5-2 mm from the alveolar crest. © 2011 John Wiley & Sons A/S.

Correlation between obesity and fat-infiltrated axillary lymph nodes visualized on mammography.

PubMed

diFlorio Alexander, Roberta M; Haider, Steffen J; MacKenzie, Todd; Goodrich, Martha E; Weiss, Julie; Onega, Tracy

2018-01-05

Using screening mammography, this study investigated the association between obesity and axillary lymph node (LN) size and morphology. We conducted a retrospective review of 188 females who underwent screening mammography at an academic medical centre. Length and width of the LN and hilum were measured in the largest, mammographically visible axillary node. The hilo-cortical ratio (HCR) was calculated as the hilar width divided by the cortical width. Measurements were performed by a board certified breast radiologist and a resident radiology physician. Inter-rater agreement was assessed with Pearson correlation coefficient. We performed multivariable regression analysis for associations of LN measurements with body mass index (BMI), breast density and age. There was a strong association between BMI and LN dimensions, hilum dimensions and HCR (p < 0.001 for all metrics). There was no significant change in cortex width with increasing BMI (p = 0.15). Increases in LN length and width were found with increasing BMI [0.6 mm increase in length per unit BMI, 95% CI (0.4-0.8), p < 0.001 and0.3 mm increase in width per unit BMI, 95% CI(0.2-0.4), p < 0.001, respectively]. Inter-rater reliability for lymph node and hilum measurements was 0.57-0.72. We found a highly significant association between increasing BMI and axillary LN dimensions independent of age and breast density with strong interobserver agreement. The increase in LN size was driven by expansion of the LN hilum secondary to fat infiltration. Advances in knowledge: This preliminary work determined a relationship between fat infiltrated axillary lymph nodes and obesity.

Investigation of a pre-clinical mandibular bone notch defect model in miniature pigs: clinical computed tomography, micro-computed tomography, and histological evaluation.

PubMed

Carlisle, Patricia L; Guda, Teja; Silliman, David T; Lien, Wen; Hale, Robert G; Brown Baer, Pamela R

2016-02-01

To validate a critical-size mandibular bone defect model in miniature pigs. Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks. In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect. The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.

Relationship between vertical facial patterns and dental arch form in class II malocclusion.

PubMed

Grippaudo, Cristina; Oliva, Bruno; Greco, Anna Lucia; Sferra, Simone; Deli, Roberto

2013-11-07

The purpose of this study is to evaluate the relationship between dental arch form and the vertical facial pattern determined by the angle between the mandibular plane and the anterior cranial base (Sella-nasion/mandibular plane angle (SN-MP)) in skeletal class II untreated patients. A sample of 73 Caucasians patients with untreated skeletal class II in permanent dentition was divided into three groups according to the values of the angle SN-MP. An evaluation of the arch form was performed by angular and linear relation values on each patient. Regression analysis was used to determine the statistical significance of the relationships between SN-MP angle and dental arch form. The differences among the three groups were analyzed for significance using a variance analysis. A decrease of the upper arch transversal diameters in high SN-MP angle patients and an increase in low angle SN-MP ones (P<0.05) were shown. Result analysis showed a change in upper arch shape, with a smaller intercanine width in patients with high SN-MP angle and a greater one in low angle patients. As SN-MP angle increased, the upper arch form tended to be narrower. No statistically significant difference in mandibular arch form among the three groups was found, except the angle value related to incisors position. The results showed the association between the upper dental arch form and the vertical facial pattern. On the contrary, the lower arch form was not related to the mandibular divergence.

Effect of lip bumpers on mandibular arch dimensions.

PubMed

Hashish, Dena Ibrahim; Mostafa, Yehya Ahmed

2009-01-01

The aim of this systematic review was to examine the effects of lip bumper therapy on mandibular arch dimensions. A literature survey of PubMed, EMBASE, Cochrane Central, and Cochrane Database of Systematic Reviews (www.cochrane.org) was conducted from December 1968 to January 2007. Human studies, randomized clinical trials, prospective and retrospective studies, and studies discussing the effect of lip bumpers on the arch and teeth were included. Two reviewers independently selected and extracted the data. Of the 52 studies found in the search, only 1 met the inclusion criteria. The results showed increases in arch dimensions that included an increase in arch length. This was attributed to incisor proclination, distalization, and distal tipping of the molars. There was also an increase in the arch width seen in the intercanine and deciduous intermolar and premolar distances. The long-term stability of the effects of the lip bumper need to be elucidated.

Selected toxic and essential heavy metals in impacted teeth and the surrounding mandibular bones of people exposed to heavy metals in the environment.

PubMed

Malara, Piotr; Fischer, Agnieszka; Malara, Beata

2016-01-01

The elemental composition of bones and teeth can allow exposure to heavy metals in the environment to be estimated. The aim of this study was to determine whether impacted mandibular teeth and the surrounding bones can be used as biomonitoring media to assess exposure to heavy metals. The research materials were 67 impacted lower third molars and samples of the cortical bone removed when the wisdom teeth were surgically extracted. The samples were from people living in two areas with different environmental concentrations of heavy metals. The cadmium, chromium, copper, iron, lead, manganese, and zinc concentrations in the samples were determined by atomic absorption spectrometry with flame atomization. The cadmium and lead concentrations in the impacted third molars and the bones surrounding the teeth were significantly higher for people living in the relatively polluted Ruda Slaska region than for people living in Bielsko-Biala region. Significantly higher chromium, copper, manganese, and zinc concentrations were found in the bones surrounding the impacted teeth from people living in Ruda Slaska than in the bones surrounding the impacted teeth from people living in Bielsko-Biala. The cadmium concentrations in impacted teeth and the surrounding bones were significantly positively correlated. The results indicated that impacted mandibular teeth and the surrounding mandibular bones may reflect the exposure of people to cadmium and lead in the environment. This conclusion, however, must be verified in future research projects designed to exclude the possibility of additional dietary, occupational, and other types of exposure to heavy metals.

Postnatal width changes in the internal structures of the human mandible: a longitudinal three-dimensional cephalometric study using implants.

PubMed

Baumrind, S; Korn, E L

1992-12-01

This paper presents case-specific quantitative evidence of the systematic lateral displacement of metallic implants in the mandibles of treated and untreated human subjects between the ages of 8.5 and 15.5 years. This evidence appears to be consistent with the inference of small, but systematic increases in distance between the internal structures of the two sides of the osseous mandible during growth. Such a conclusion, however, is inconsistent with traditional beliefs that the internal structures of the mandibular symphysis fuse at the midline during the first post-natal year and remain dimensionally constant thereafter. We recently published evidence of statistically significant transverse displacement of metallic implants in the mandibular body region for 12 of 28 subjects for whom longitudinal data were available. Of the twelve subjects for whom statistically significant changes were observed, widening occurred in eleven cases and narrowing in one. Matching data are now available on concurrent ramus changes for 22 of the same 28 subjects, including 11 of the 12 for whom statistically significant width changes had previously been noted in the body region. In eight of these 11 subjects, statistically significant widening in the ramus region was also observed. No subject had statistically significant widening in the ramus region without also having statistically significant widening in the body region. No subject had statistically significant trans-ramus narrowing.

Stress distribution of single-implant-retained overdenture reinforced with a framework: A finite element analysis study.

PubMed

Amaral, Camilla F; Gomes, Rafael S; Rodrigues Garcia, Renata C M; Del Bel Cury, Altair A

2018-05-01

Studies have demonstrated the effectiveness of a single-implant-retained mandibular overdenture for elderly patients with edentulism. However, due to the high concentration of stress around the housing portion of the single implant, this prosthesis tends to fracture at the anterior region more than the 2-implant-retained mandibular overdenture. The purpose of this finite-element analysis study was to evaluate the stress distribution in a single-implant-retained mandibular overdenture reinforced with a cobalt-chromium framework, to minimize the incidence of denture base fracture. Two 3-dimensional finite element models of mandibular overdentures supported by a single implant with a stud attachment were designed in SolidWorks 2013 software. The only difference between the models was the presence or absence of a cobalt-chromium framework at the denture base between canines. Subsequently, the models were imported into the mathematical analysis software ANSYS Workbench v15.0. A mesh was generated with an element size of 0.7 mm and submitted to convergence analysis before mechanical simulation. All materials were considered to be homogeneous, isotropic, and linearly elastic. A 100-N load was applied to the incisal edge of the central mandibular incisors at a 30-degree angle. Maximum principal stress was calculated for the overdenture, von Mises stress was calculated for the attachment and implant, and minimum principal stress was calculated for cortical and cancellous bone. In both models, peak stress on the overdenture was localized at the anterior intaglio surface region around the implant. However, the presence of the framework reduced the stress by almost 62% compared with the overdenture without a framework (8.7 MPa and 22.8 MPa, respectively). Both models exhibited similar stress values in the attachment, implant, and bone. A metal framework reinforcement for a single-implant-retained mandibular overdenture concentrates less stress through the anterior area of the prosthesis and could minimize the incidence of fracture. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Toward Patient Specific Long Lasting Metallic Implants for Mandibular Segmental Defects

NASA Astrophysics Data System (ADS)

Shayesteh Moghaddam, Narges

Mandibular defects may result from tumor resection, trauma, or inflammation. The goals of mandibular reconstruction surgeries are to restore mandible function and aesthetics. To this end, surgeons use a combination of bone grafts and metallic implants. These implants have drastically different mechanical properties than the surrounding bone. As a result, the stress distribution in the mandible changes after surgery. The long-term abnormal stress/strain distribution may lead to either graft failure due to bone resorption as a result of stress shielding, or hardware failure due to stress concentrations. During the healing period of six to nine months it is important that complete immobilization, bringing mandibular micro-motion down to the level of 200-500 mum during chewing, is achieved. After this period it is desired that bone undergo normal stress for long-term success of the treatment. Although current high stiffness fixation hardware accomplishes this immobilization during the healing period, the hardware continues to alter the normal stress-strain trajectory seen during chewing once the engrafted bone heals. Over the long-term, the immobilized and stress-shielded engrafted bone tends to resorb. On the other hand, hardware fracturing or/and screw loosening is observed as the stress is concentrated at certain locations on the hardware. Equally as important is the permanent loss of chewing power due to the altered stress-strain relationships. The first stage of this research is to study the problems encountered following a mandibular segmental defect reconstructive surgery. To this end, we constructed a finite element model of a healthy mandible, which includes cortical and cancellous bone, teeth (enamel and dentin components), and the periodontal ligament. Using this model, we studied a healthy adult mandible under maximum molar bite force for stress, strain, displacement, and reaction force distribution. For mandibular segmental defect reconstruction the current standard of care consists of the use of Surgical Grade 5 titanium also known as Ti-6Al-4V hardware and either a single or double fibula barrel vascularized bone graft. We expanded our model to simulate the effects of this surgery. The expanded model includes both single and double barrel fibular bone graft repair of a right M1-M3 containing section of the mandible, Ti-6Al-4V fixation hardware and screws. We found that the stiffness mismatch between the fixation hardware and the bone causes stress shielding on the host mandible and the bone graft, and stress concentration at the fixation hardware and screws. The simulations results show that while a double-barrel graft is preferred, in the long-term it does not create the optimal outcome due to the abnormal stress pattern. To improve the long-term outcome with metallic implants it is essential to recreate the normal stress pattern. To achieve this outcome we investigated the use of porous nitinol as a substitute for the currently used titanium hardware. While NiTi already has a lower stiffness than titanium, it is possible to add porosity to further reduce the stiffness to be closer to that of cortical bone. The ultimate goal is to create fixation hardware that has sufficient stiffness for immobilization while recreating the normal stress pattern in the bone. Using a finite element model of devices fabricated from Surgical Grade 5 titanium and NiTi, we have found that stiffness-tuned NiTi hardware with conventional geometries should result in recreation of normal stress-strain trajectories and better treatment outcome. Finally, to further improve the outcome, we suggest the use of a two-stage mechanism Bone Bandaid which supports both the immobilization/healing and regenerative phases of mandibular segmental defect treatment. This device is made of two materials. The stiff Ti-6Al-4V portion provides the support during the healing period and is disengaged afterwards. The second material is a NiTi wire-frame to facilitate normal stress distribution after the initial healing period. The titanium part of this fixation hardware is released following radiological verification that the surgical osteotomies have healed. The release procedure is performed under local anesthetic via a microsurgical tool. With the titanium fixation hardware no longer functional, the NiTi webbing would act as a superstructure, like a skin, to the underlying grafted cortical bone. This device facilitates stress transduction through the normal stress-strain trajectories, allows restoration of power, drives cortical bone remodeling and strengthening, provides long-term strength, and a good bone bed for dental implants. If bone chips are used, instead of single or double bone graft, the webbing is more likely to support the bone chips while they are being incorporated with the mandible. We have performed computer simulation to investigate the two stages of the operation of the device. Our FEA results indicate that the Bone Bandaid supports both the immobilization needed during healing and the distribution of stress through the engrafted bone once it has healed. (Abstract shortened by ProQuest.).

Computer-aided design evaluation of harvestable mandibular bone volume: a clinical and tomographic human study.

PubMed

Verdugo, Fernando; Simonian, Krikor; Raffaelli, Luca; D'Addona, Antonio

2014-06-01

To evaluate and compare the volume of bone graft material that can be safely harvested from the mandibular symphysis and rami using a computer-aided design (CAD) software program. Preoperative computerized tomography scans from 40 patients undergoing bone augmentation procedures were analyzed. Symphysis and rami cross sections were mapped using a CAD software program (AutoCAD(®), Autodesk, Inc., San Rafael, CA, USA) to evaluate the bone volume that can be safely harvested. CAD calculations were contrasted to intrasurgical measurements in a subgroup of 20 individuals. CAD calculations yielded a safe harvestable osseous volume of 1.44 cm(3) ± 0.49 for the symphysis and 0.82 cm(3) ± 0.21 for each ramus (p < .0001, confidence interval [CI] 95%: 0.47-0.78). These measurements were significantly lower (p < .0001) than the bone volumes harvested intrasurgically for both symphysis and ramus, respectively (2.40 cm(3) ± 0.50 vs. 2.65 cm(3) ± 0.45). CAD calculations of harvestable symphysis and ramus bone translated into an average of 2.40 cm(3) ± 0.50 (range: 1.80-3.10 cm(3)) and 2.65 cm(3) ± 0.45 (range: 1.90-3.50) of particulate bone graft intrasurgically, respectively. Ramus cortical was significantly thicker than the symphysis cortical, 2.9 ± 0.4 mm versus 2.19 mm ± 0.4 mm (p < .0001, CI 95%: 0.45-1.03). The symphysis and rami are good harvesting sources to obtain dense corticocancellous bone. The significant volumetric CAD differences between the symphysis and ramus seem to balance out intrasurgically and may be due to the greater cortical bone volume at the ramus area. It is plausible to harvest an average of 7.70 cm(3) from the symphysis and rami alone. The use of a CAD software program can enhance surgical treatment planning prior to bone transplantation. © 2012 Wiley Periodicals, Inc.

Third molar development: measurements versus scores as age predictor.

PubMed

Thevissen, P W; Fieuws, S; Willems, G

2011-10-01

Human third molar development is widely used to predict chronological age of sub adult individuals with unknown or doubted age. For these predictions, classically, the radiologically observed third molar growth and maturation is registered using a staging and related scoring technique. Measures of lengths and widths of the developing wisdom tooth and its adjacent second molar can be considered as an alternative registration. The aim of this study was to verify relations between mandibular third molar developmental stages or measurements of mandibular second molar and third molars and age. Age related performance of stages and measurements were compared to assess if measurements added information to age predictions from third molar formation stage. The sample was 340 orthopantomograms (170 females, 170 males) of individuals homogenously distributed in age between 7 and 24 years. Mandibular lower right, third and second molars, were staged following Gleiser and Hunt, length and width measurements were registered, and various ratios of these measurements were calculated. Univariable regression models with age as response and third molar stage, measurements and ratios of second and third molars as predictors, were considered. Multivariable regression models assessed if measurements or ratios added information to age prediction from third molar stage. Coefficients of determination (R(2)) and root mean squared errors (RMSE) obtained from all regression models were compared. The univariable regression model using stages as predictor yielded most accurate age predictions (males: R(2) 0.85, RMSE between 0.85 and 1.22 year; females: R(2) 0.77, RMSE between 1.19 and 2.11 year) compared to all models including measurements and ratios. The multivariable regression models indicated that measurements and ratios added no clinical relevant information to the age prediction from third molar stage. Ratios and measurements of second and third molars are less accurate age predictors than stages of developing third molars. Copyright © 2011 Elsevier Ltd. All rights reserved.

Peripheral giant cell granuloma of the mandibular condyle presenting as a preauricular mass.

PubMed

Ozcan, Cengiz; Apaydin, F Demir; Görür, Kemal; Apa, Duygu Düşmez

2005-03-01

Preauricular mass is a common symptom for patients presenting to the otorhinolaryngologist with parotid disease. Some rare extraparotid lesions, originating from the temporomandibular joint and the mandible itself, also share the same localization and therefore are to be taken into consideration for the differential diagnosis with parotid lesions. Giant cell granuloma (GCG) was first described by Jaffe in 1953. Peripheral GCG (PGCG) is an exophytic soft tissue lesion originating from the periodontal ligament and periosteum. It is located only within the oral cavity. Central GCG (CGCG) is an uncommon benign fibro-osseous lesion generally presenting as an expansible mass with cortical bone defect. It is generally located in the mandible. The brown tumor of hyperparathyroidism and giant cell tumor must be ruled out because of the microscopic similarities of these lesions. The first case of PGCG of the mandible condyle is presented, and attention is drawn to mandibular diseases for the differential diagnosis of the preauricular mass.

Elastic properties and apparent density of human edentulous maxilla and mandible

PubMed Central

Seong, Wook-Jin; Kim, Uk-Kyu; Swift, James Q.; Heo, Young-Cheul; Hodges, James S.; Ko, Ching-Chang

2009-01-01

The aim of this study aim was to determine whether elastic properties and apparent density of bone differ in different anatomical regions of the maxilla and mandible. Additional analyses assessed how elastic properties and apparent density were related. Four pairs of edentulous maxilla and mandibles were retrieved from fresh human cadavers. Bone samples from four anatomical regions (maxillary anterior, maxillary posterior, mandibular anterior, mandibular posterior) were obtained. Elastic modulus (EM) and hardness (H) were measured using the nano-indentation technique. Bone samples containing cortical and trabecular bone were used to measure composite apparent density (cAD) using Archimedes’ principle. Statistical analyses used repeated measures ANOVA and Pearson correlations. Bone physical properties differed between regions of the maxilla and mandible. Generally, mandible had higher physical property measurements than maxilla. EM and H were higher in posterior than in anterior regions; the reverse was true for cAD. Posterior maxillary cAD was significantly lower than that in the three other regions. PMID:19647417

Elastic properties and apparent density of human edentulous maxilla and mandible.

PubMed

Seong, W-J; Kim, U-K; Swift, J Q; Heo, Y-C; Hodges, J S; Ko, C-C

2009-10-01

The aim of this study was to determine whether elastic properties and apparent density of bone differ in different anatomical regions of the maxilla and mandible. Additional analyses assessed how elastic properties and apparent density were related. Four pairs of edentulous maxilla and mandibles were retrieved from fresh human cadavers. Bone samples from four anatomical regions (maxillary anterior, maxillary posterior, mandibular anterior, mandibular posterior) were obtained. Elastic modulus (EM) and hardness (H) were measured using the nano-indentation technique. Bone samples containing cortical and trabecular bone were used to measure composite apparent density (cAD) using Archimedes' principle. Statistical analyses used repeated measures ANOVA and Pearson correlations. Bone physical properties differed between regions of the maxilla and mandible. Generally, mandible had higher physical property measurements than maxilla. EM and H were higher in posterior than in anterior regions; the reverse was true for cAD. Posterior maxillary cAD was significantly lower than that in the three other regions.

Comparison of acellular dermal graft and palatal autograft in the reconstruction of keratinized gingiva around dental implants: a case report.

PubMed

Yan, Ji-Jong; Tsai, Alex Yi-Min; Wong, Man-Ying; Hou, Lein-Tuan

2006-06-01

The use of autogenous gingival grafts has proved to be an effective and predictable way to increase the amount of keratinized gingiva. However, discomfort and pain at the donor site are unavoidable. Acellular dermal matrix (ADM) allograft can be used as a donor tissue to eliminate the need for another surgical site and alleviate pain and trauma. The purpose of this study was to evaluate the effectiveness of ADM allograft in increasing the width of keratinized gingiva around dental implants. A patient with inadequate keratinized gingiva around dental implants in maxillary and mandibular anterior regions received either an ADM graft or palatal autograft by random allocation. The width of keratinized gingiva and other clinical periodontal parameters were recorded initially and at 3 and 6 months after surgery. Both grafts provided satisfactory results. The width of keratinized tissues was increased by using the ADM allograft, but by a lesser amount than seen with the autogenous gingival graft.

Cortical bone deficit and fat infiltration of bone marrow and skeletal muscle in ambulatory children with mild spastic cerebral palsy

PubMed Central

Whitney, Daniel G.; Singh, Harshvardhan; Miller, Freeman; Barbe, Mary F.; Slade, Jill M.; Pohlig, Ryan T.; Modlesky, Christopher M.

2016-01-01

Introduction Nonambulatory children with severe cerebral palsy (CP) have an underdeveloped bone architecture, low bone strength and a high degree of fat infiltration in the lower extremity musculature. The present study aims to determine if such a profile exists in ambulatory children with mild CP and if excess fat infiltration extends into the bone marrow. Materials and methods Ambulatory children with mild spastic CP and typically developing children (4 to 11 years; 12/group) were tested. Magnetic resonance imaging was used to estimate cortical, medullary and total bone volume and width, bone strength [i.e., section modulus (Z) and polar moment of inertia (J)], and bone marrow fat concentration in the midtibia, and muscle volume, intermuscular, subfascial, and subcutaneous adipose tissue (AT) volume and intramuscular fat concentration in the midleg. Physical activity monitors worn on the ankle were used to assess physical activity. Results There were no group differences in age, height, body mass, body mass percentile, BMI, BMI percentile or tibia length, but children with CP had lower height percentile (19th vs. 50th percentile) and total physical activity counts (44 %) than controls (both p < 0.05). Children with CP also had lower cortical volume (30 %), cortical width in the posterior (16 %) and medial (32 %) portion of the shaft, total bone width in the medial-lateral direction (15 %), Z in the medial-lateral direction (34 %), J (39 %) and muscle volume (39 %), and higher bone marrow fat concentration (82.1 ± 1.8 % vs. 80.5 ± 1.9 %), subfascial AT volume (3.3 fold) and intramuscular fat concentration (25.0 ± 8.0 % vs. 16.1 ± 3.3 %) than controls (all p < 0.05). When tibia length was statistically controlled, all group differences in bone architecture, bone strength, muscle volume and fat infiltration estimates, except posterior cortical width, were still present (all p < 0.05). Furthermore, a higher intermuscular AT volume in children with CP compared to controls emerged (p < 0.05). Conclusions Ambulatory children with mild CP exhibit an underdeveloped bone architecture and low bone strength in the midtibia and a greater infiltration of fat in the bone marrow and surrounding musculature compared to typically developing children. Whether the deficit in the musculoskeletal system of children with CP is associated with higher chronic disease risk and whether the deficit can be mitigated requires further investigation. PMID:27732905

Cortical bone deficit and fat infiltration of bone marrow and skeletal muscle in ambulatory children with mild spastic cerebral palsy.

PubMed

Whitney, Daniel G; Singh, Harshvardhan; Miller, Freeman; Barbe, Mary F; Slade, Jill M; Pohlig, Ryan T; Modlesky, Christopher M

2017-01-01

Nonambulatory children with severe cerebral palsy (CP) have underdeveloped bone architecture, low bone strength and a high degree of fat infiltration in the lower extremity musculature. The present study aims to determine if such a profile exists in ambulatory children with mild CP and if excess fat infiltration extends into the bone marrow. Ambulatory children with mild spastic CP and typically developing children (4 to 11years; 12/group) were compared. Magnetic resonance imaging was used to estimate cortical bone, bone marrow and total bone volume and width, bone strength [i.e., section modulus (Z) and polar moment of inertia (J)], and bone marrow fat concentration in the midtibia, and muscle volume, intermuscular, subfascial, and subcutaneous adipose tissue (AT) volume and intramuscular fat concentration in the midleg. Accelerometer-based activity monitors worn on the ankle were used to assess physical activity. There were no group differences in age, height, body mass, body mass percentile, BMI, BMI percentile or tibia length, but children with CP had lower height percentile (19th vs. 50th percentile) and total physical activity counts (44%) than controls (both p<0.05). Children with CP also had lower cortical bone volume (30%), cortical bone width in the posterior (16%) and medial (32%) portions of the shaft, total bone width in the medial-lateral direction (15%), Z in the medial-lateral direction (34%), J (39%) and muscle volume (39%), and higher bone marrow fat concentration (82.1±1.8% vs. 80.5±1.9%), subfascial AT volume (3.3 fold) and intramuscular fat concentration (25.0±8.0% vs. 16.1±3.3%) than controls (all p<0.05). When tibia length was statistically controlled, all group differences in bone architecture, bone strength, muscle volume and fat infiltration estimates, except posterior cortical bone width, were still present (all p<0.05). Furthermore, a higher intermuscular AT volume in children with CP compared to controls emerged (p<0.05). Ambulatory children with mild spastic CP exhibit an underdeveloped bone architecture and low bone strength in the midtibia and a greater infiltration of fat in the bone marrow and surrounding musculature compared to typically developing children. Whether the deficit in the musculoskeletal system of children with CP is associated with higher chronic disease risk and whether the deficit can be mitigated requires further investigation. Copyright © 2016 Elsevier Inc. All rights reserved.

Hemispheric comparisons of neuron density in the planum temporale of schizophrenia and nonpsychiatric brains

PubMed Central

Smiley, John F.; Rosoklija, Gorazd; Mancevski, Branislav; Pergolizzi, Denise; Figarsky, Khadija; Bleiwas, Cynthia; Duma, Aleksej; Mann, J. John; Javitt, Daniel C.; Dwork, Andrew J.

2010-01-01

Postmortem and in vivo studies of schizophrenia frequently reveal reduced cortical volume, but the underlying cellular abnormalities are incompletely defined. One influential hypothesis, especially investigated in Brodmann’s area 9 of prefrontal cortex, is that the number of neurons is normal, and the volume change is caused by reduction of the surrounding neuropil. However, studies have differed on whether the cortex has the increased neuron density that is predicted by this hypothesis. In a recent study of bilateral planum temporale (PT), we reported smaller volume and width of the outer cortex (layers I-III), especially in the left hemisphere, among subjects with schizophrenia. In the present study, we measured neuron density and size in the same PT samples, and also in prefrontal area 9 of the same brains. In the PT, separate stereological measurements were made in layers II, IIIc, and VI, whereas area 9 was sampled in layer IIIb-c. In both cortical regions, there was no significant effect of schizophrenia on neuronal density or size. There was, nevertheless, a trend-level right>left hemispheric asymmetry of neuron density in the PT, which may partially explain the previously reported left>right asymmetry of cortical width. In schizophrenia, our findings suggest that closer packing of neurons may not always explain reduced cortical volume, and subtly decreased neuron number may be a contributing factor. PMID:21377842

Roles of N-methyl-d-aspartate receptors during the sensory stimulation-evoked field potential responses in mouse cerebellar cortical molecular layer.

PubMed

Xu, Yin-Hua; Zhang, Guang-Jian; Zhao, Jing-Tong; Chu, Chun-Ping; Li, Yu-Zi; Qiu, De-Lai

2017-11-01

The functions of N-methyl-d-aspartate receptors (NMDARs) in cerebellar cortex have been widely studied under in vitro condition, but their roles during the sensory stimulation-evoked responses in the cerebellar cortical molecular layer in living animals are currently unclear. We here investigated the roles of NMDARs during the air-puff stimulation on ipsilateral whisker pad-evoked field potential responses in cerebellar cortical molecular layer in urethane-anesthetized mice by electrophysiological recording and pharmacological methods. Our results showed that cerebellar surface administration of NMDA induced a dose-dependent decrease in amplitude of the facial stimulation-evoked inhibitory responses (P1) in the molecular layer, accompanied with decreases in decay time, half-width and area under curve (AUC) of P1. The IC 50 of NMDA induced inhibition in amplitude of P1 was 46.5μM. In addition, application of NMDA induced significant increases in the decay time, half-width and AUC values of the facial stimulation-evoked excitatory responses (N1) in the molecular layer. Application of an NMDAR blocker, D-APV (250μM) abolished the facial stimulation-evoked P1 in the molecular layer. These results suggested that NMDARs play a critical role during the sensory information processing in cerebellar cortical molecular layer in vivo in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

Intracortical signal processing of periodontal ligament sensations in rat.

PubMed

Minoda, Aoi; Mizoguchi, Naoko; Kobayashi, Masayuki; Suda, Naoto; Muramoto, Kazuyo

2017-07-04

The somatosensory information from the orofacial region, including the periodontal ligament (PDL), is processed in a manner that differs from that used for other body somatosensory information in the related cortices. It was reported that electrical stimulation to rat PDL elicited activation of the insular oral region (IOR) and the primary (S1) and secondary (S2) somatosensory cortices. However, the physiological relationship between S1 and S2/IOR is not well understood. To address this issue, we performed in vivo optical imaging using a voltage-sensitive dye. Our results demonstrated that the electrical stimulation to the PDL of the mandibular incisor evoked the simultaneous activation of S1 and the S2/IOR. The stimulation to the initial response area of the S1 evoked responses in the S2/IOR, and vice versa. An injection of tetrodotoxin (TTX) to the cortical region between S1 and S2/IOR attenuated such elicited responses only in the non-stimulated cortical partner site. The cortico-cortical interaction between S1 and S2/IOR was suppressed by the application of TTX, indicating that these two cortical regions bi-directionally communicate the signal processing of PDL sensations. An injection of FluoroGold™ (FG) to the initial response area in S1 or the S2/IOR showed that FG-positive cells were scattered in the non-injected cortical counterpart. This morphological result demonstrated the presence of a bi-directional intracortical connection between the initial response areas in S1 and the S2/IOR. These findings suggest the presence of a mutual connection between S1 and the S2/IOR as an intracortical signal processing network for orofacial nociception. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Soft, hard-tissues and pharyngeal airway volume changes following maxillomandibular transverse osteodistraction: Computed tomography and three-dimensional laser scanner evaluation.

PubMed

Bianchi, Francesca Antonella; Gerbino, Giovanni; Corsico, Marina; Schellino, Eleonora; Barla, Niccolò; Verzè, Laura; Ramieri, Guglielmo

2017-01-01

Maxillomandibular transverse osteodistraction (MMTOD) is an alternative approach to the traditional treatment for transverse maxillary and mandibular deficiencies and crowding. The aim was to report soft and hard-tissues changes and airway volume variation. In this study, skeletally mature, non-syndromic patients with transverse maxillary and mandibular hypoplasia, who underwent a MMTOD between 2010 and 2012, were included. Surgical changes were analysed using clinical evaluation, three-dimensional facial surface data and computed tomography analysis before (T0) and after the completion of post-op orthodontic treatment (T1). Nineteen patients (eight males and eleven females; average age: 26.3 years) were enrolled. MMTOD produces facial changes in the cheek, paranasal areas, nasal base and chin. Facial changes are mostly explained by the underlying skeletal movements, which are essentially represented by the transverse enlargement of both the maxilla and the mandible. Following MMTOD, the airway volume and the lateral dimension of the cross-sectional airway increased significantly. MMTOD is a technique that allows an increase in airway volume and in both maxillary and mandibular arch perimeters simultaneously by increasing skeletal width. Facial appearance is improved and a stable occlusion is obtained. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Mandibular arch form: the relationship between dental and basal anatomy.

PubMed

Ronay, Valerie; Miner, R Matthew; Will, Leslie A; Arai, Kazuhito

2008-09-01

We investigated mandibular dental arch form at the levels of both the clinically relevant application points of the orthodontic bracket and the underlying anatomic structure of the apical base. The correlation of both forms was evaluated and examined to determine whether the basal arch could be used to derive a standardized clinical arch form. Thirty-five mandibular dental casts (skeletal and dental Class I) were laser scanned, and a 3-dimensional virtual model was created. Two reference points (FA, the most prominent part of the central lobe on each crown's facial surface, and WALA, a point at the height of the mucogingival junction) were selected for each tooth from the right to the left first molars. The FA and WALA arch forms were compared, and the distances between corresponding points and intercanine and intermolar widths were analyzed. Both arch forms were highly individual and the tooth values scattered. Nevertheless, a highly significant relationship between the FA and WALA curves was found, especially in the canine (0.75) and molar (0.87) areas. Both FA and WALA point-derived arch forms were individual and therefore could not be defined by a generalized shape. WALA points proved to be a useful representation of the apical base and helpful in the predetermination of an individualized dental arch form.

An immunohistochemical and ultrastructural study of the pericellular matrix of uneroded hypertrophic chondrocytes in the mandibular condyle of aged c-src-deficient mice.

PubMed

Shibata, Shunichi; Baba, Otto; Oda, Tsuyoshi; Yokohama-Tamaki, Tamaki; Qin, Chunlin; Butler, William T; Sakakura, Yasunori; Takano, Yoshiro

2008-03-01

Previous studies indicate that hypertrophic chondrocytes can transdifferentiate or dedifferentiate and redifferentiate into bone cells during the endochondral bone formation. Mandibular condyle in aged c-src-deficient mice has incremental line-like striations consisting of cartilaginous and non-cartilaginous layers, and the former contains intact hypertrophic chondrocytes in uneroded lacunae. The purpose of this study is to determine the phenotype changes of uneroded hypertrophic chondrocytes. Immunohistochemical and ultrastructural examinations of the pericellular matrix of hypertrophic chondrocytes in the upper, middle, and lower regions of the mandibular condyle were conducted in aged c-src-deficient mice, using several antibodies of cartilage/bone marker proteins. Co-localisation of aggrecan, type I collagen, and dentin matrix protein-1 (DMP-1) or matrix extracellular phosphoprotein (MEPE) was detected in the pericellular matrix of the middle region. Ultrastructurally, granular substances in the pericellular matrix of the middle region were the remains of upper region chondrocytes, which were mixed with thick collagen fibrils. In the lower region, the width of the pericellular matrix and the amount of collagen fibrils were increased. Versican, type I collagen, DMP-1, and MEPE were detected in the osteocyte lacunae. Additionally, DMP-1 and MEPE were detected in the pericellular matrix of uneroded hypertrophic chondrocytes located in the lower, peripheral region of the mandibular condyle in younger c-src-deficient mice, but not in the aged wild-type mice. These results indicate that long-term survived, uneroded hypertrophic chondrocytes, at least in a part, acquire osteocytic characteristics.

Characterizing mandibular growth using three-dimensional imaging techniques and anatomic landmarks

PubMed Central

Kelly, Michael P.; Vorperian, Houri K.; Wang, Yuan; Tillman, Katelyn K.; Werner, Helen M.; Chung, Moo K.; Gentry, Lindell R.

2017-01-01

Objective To provide quantitative data on the multi-planar growth of the mandible, this study derived accurate linear and angular mandible measurements using landmarks on three dimensional (3D) mandible models. This novel method was used to quantify 3D mandibular growth and characterize the emergence of sexual dimorphism. Design Cross-sectional and longitudinal imaging data were obtained from a retrospective computed tomography (CT) database for 51 typically developing individuals between the ages of one and nineteen years. The software Analyze was used to generate 104 3DCT mandible models. Eleven landmarks placed on the models defined six linear measurements (lateral condyle, gonion, and endomolare width, ramus and mental depth, and mandible length) and three angular measurements (gonion, gnathion, and lingual). A fourth degree polynomial fit quantified growth trends, its derivative quantified growth rates, and a composite growth model determined growth types (neural/cranial and somatic/skeletal). Sex differences were assessed in four age cohorts, each spanning five years, to determine the ontogenetic pattern producing sexual dimorphism of the adult mandible. Results Mandibular growth trends and growth rates were non-uniform. In general, structures in the horizontal plane displayed predominantly neural/cranial growth types, whereas structures in the vertical plane had somatic/skeletal growth types. Significant prepubertal sex differences in the inferior aspect of the mandible dissipated when growth in males began to outpace that of females at eight to ten years of age, but sexual dimorphism re-emerged during and after puberty. Conclusions This 3D analysis of mandibular growth provides preliminary normative developmental data for clinical assessment and craniofacial growth studies. PMID:28161602

Three-Dimensional Finite Element Analysis of Varying Diameter and Connection Type in Implants with High Crown-Implant Ratio.

PubMed

Moraes, Sandra Lúcia Dantas de; Verri, Fellippo Ramos; Santiago, Joel Ferreira; Almeida, Daniel Augusto de Faria; Lemos, Cleidiel Aparecido Araujo; Gomes, Jéssica Marcela de Luna; Pellizzer, Eduardo Piza

2018-01-01

The aim of this study was to evaluate the effect of varying the diameter, connection type and loading on stress distribution in the cortical bone for implants with a high crown-implant ratio. Six 3D models were simulated with the InVesalius, Rhinoceros 3D 4.0 and SolidWorks 2011 software programs. Models were composed of bone from the posterior mandibular region; they included an implant of 8.5 mm length, diameter Ø 3.75 mm or Ø 5.00 mm and connection types such as external hexagon (EH), internal hexagon (IH) and Morse taper (MT). Models were processed using the Femap 11.2 and NeiNastran 11.0 programs and by using an axial force of 200 N and oblique force of 100 N. Results were recorded in terms of the maximum principal stress. Oblique loading showed high stress in the cortical bone compared to that shown by axial loading. The results showed that implants with a wide diameter showed more favorable stress distribution in the cortical bone region than regular diameter, regardless of the connection type. Morse taper implants showed better stress distribution compared to other connection types, especially in the oblique loading. Thus, oblique loading showed higher stress concentration in cortical bone tissue when compared with axial loading. Wide diameter implant was favorable for improved stress distribution in the cortical bone region, while Morse taper implants showed lower stress concentration than other connections.

Radiomorphometric indices of mandibular bones in an 18th century population.

PubMed

Ivanišević Malčić, Ana; Matijević, Jurica; Vodanović, Marin; Knezović Zlatarić, Dubravka; Prpić Mehičić, Goranka; Jukić, Silvana

2015-05-01

To estimate four radiomorphometric indices of mandibular bones in an 18th century population sample, and possibly associate the findings with bone mass loss related to sex, age, nutritional habits and pathologies reflecting on the bone. Thirty-six sculls (31 males, 5 females), recovered from the crypt of Požega Cathedral in Croatia were analyzed. Age estimation was based on tooth wear, and Eichner class was determined according to the number of occlusal supporting zones. The parameters in recording analogue orthopantomographs were set to constant current of 16 mA, exposure time of 14.1s, and voltage between 62-78 kV. Films were processed in an automatic dark chamber processor for 12 min, and digitized at 8-bit, 300 dpi. The thickness of the mandibular cortex was assessed below the mental foramen (MI), at antegonion (AI), at gonion (GI). Qualitative mandibular cortical index (MCI) was assessed. Average values of MI, AI and GI were 3.97 ± 0.94 mm, 2.98 ± 0.56 mm, and 1.99 ± 0.55 mm, respectively. Statistically significant differences between males and females were found for AI right (p=0.014), GI left (p=0.010) and GI average (p=0.006), and were in all cases higher in males. There were no statistically significant differences between age groups for either index (p>0.05). Considering Eichner classification the differences were not significant for MI (p=0.422), AI (p=0.516), and GI (p=0.443), but in Eichner classes II, MCI was significantly higher (p=0.02). The obtained data does not suggest generalized malnutrition or calcium, phosphorus and vitamin D deprivation in the historic population studied. Copyright © 2015 Elsevier Ltd. All rights reserved.

Implant-based three-dimensional superimposition of the growing mandible in a rabbit model.

PubMed

Parton, Andrew L; Duncan, Warwick J; Oliveira, Marcelo E; Key, Oscar; Farella, Mauro

2016-10-01

The reliable assessment of craniofacial morphological changes during growth requires invariant regions for image registration. As these regions have not yet been identified in three dimensions, intra-osseous implants are required as fiducial markers for the reliable assessment of three-dimensional (3D) mandibular growth changes. The objective of this study was to develop an animal model for the assessment of the 3D morphological changes of the mandible during growth, using implants as fiducial markers. Titanium implants were placed in the body of the mandible of six New Zealand White rabbits. Cone beam computed tomography (CBCT) scans were taken 1-week following implant placement and after an additional 8-weeks of growth. Segmentations of CBCT images were exported into custom-made scripts, implant centroids were identified, implant stability during growth calculated, and the segmented mandibles were registered on the implant centroids. The buccal cortical bone of the body of the mandible was stable during growth and suitable for fiducial marker placement. Bilateral implants resulted in more accurate rigid registration of the growing rabbit mandible than only unilateral implants. 3D mandibular growth changes were visualised by means of semi-transparencies. This animal model appears to be feasible for the assessment of the 3D morphological changes occurring during mandibular growth. To the best of our knowledge this is the first time that the implant superimposition method has been combined with 3D imaging to accurately reveal mandibular growth changes. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Deterioration of teeth and alveolar bone loss due to chronic environmental high-level fluoride and low calcium exposure.

PubMed

Simon, Maciej J K; Beil, Frank Timo; Riedel, Christoph; Lau, Grace; Tomsia, Antoni; Zimmermann, Elizabeth A; Koehne, Till; Ueblacker, Peter; Rüther, Wolfgang; Pogoda, Pia; Ignatius, Anita; Amling, Michael; Oheim, Ralf

2016-12-01

Health risks due to chronic exposure to highly fluoridated groundwater could be underestimated because fluoride might not only influence the teeth in an aesthetic manner but also seems to led to dentoalveolar structure changes. Therefore, we studied the tooth and alveolar bone structures of Dorper sheep chronically exposed to very highly fluoridated and low calcium groundwater in the Kalahari Desert in comparison to controls consuming groundwater with low fluoride and normal calcium levels within the World Health Organization (WHO) recommended range. Two flocks of Dorper ewes in Namibia were studied. Chemical analyses of water, blood and urine were performed. Mineralized tissue investigations included radiography, HR-pQCT analyses, histomorphometry, energy-dispersive X-ray spectroscopy and X-ray diffraction-analyses. Fluoride levels were significantly elevated in water, blood and urine samples in the Kalahari group compared to the low fluoride control samples. In addition to high fluoride, low calcium levels were detected in the Kalahari water. Tooth height and mandibular bone quality were significantly decreased in sheep, exposed to very high levels of fluoride and low levels of calcium in drinking water. Particularly, bone volume and cortical thickness of the mandibular bone were significantly reduced in these sheep. The current study suggests that chronic environmental fluoride exposure with levels above the recommended limits in combination with low calcium uptake can cause significant attrition of teeth and a significant impaired mandibular bone quality. In the presence of high fluoride and low calcium-associated dental changes, deterioration of the mandibular bone and a potential alveolar bone loss needs to be considered regardless whether other signs of systemic skeletal fluorosis are observed or not.

Influence of implant number on the biomechanical behaviour of mandibular implant-retained/supported overdentures: a three-dimensional finite element analysis.

PubMed

Liu, Jingyin; Pan, Shaoxia; Dong, Jing; Mo, Zhongjun; Fan, Yubo; Feng, Hailan

2013-03-01

The aim of this study was to evaluate strain distribution in peri-implant bone, stress in the abutments and denture stability of mandibular overdentures anchored by different numbers of implants under different loading conditions, through three-dimensional finite element analysis (3D FEA). Four 3D finite element models of mandibular overdentures were established, using between one and four Straumann implants with Locator attachments. Three types of load were applied to the overdenture in each model: 100N vertical and inclined loads on the left first molar and a 100N vertical load on the lower incisors. The biomechanical behaviours of peri-implant bone, implants, abutments and overdentures were recorded. Under vertical load on the lower incisors, the single-implant overdenture rotated over the implant from side to side, and no obvious increase of strain was found in peri-implant bone. Under the same loading conditions, the two-implant-retained overdenture showed more apparent rotation around the fulcrum line passing through the two implants, and the maximum equivalent stress in the abutments was higher than in the other models. In the three-implant-supported overdenture, no strain concentration was found in cortical bone around the middle implant under three loading conditions. Single-implant-retained mandibular overdentures do not show damaging strain concentration in the bone around the only implant and may be a cost-effective treatment option for edentulous patients. A third implant can be placed between the original two when patients rehabilitated by two-implant overdentures report constant and obvious denture rotation around the fulcrum line. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effect of oral ipriflavone on the rat mandible during growth.

PubMed

Maki, Kenshi; Nishida, Ikuko; Kimura, Mitsutaka

2005-02-01

Different types of ipriflavone (IF) have been reported to be effective when used as a remedy for bone loss due to osteoporosis. However, no information is available regarding the relationship between IF and jaw bone structure. The aim of this study was to examine the effect of IF on rat mandibles during the growth stage. Thirty-two 5-week-old Wistar male rats were divided into four groups. The control group was fed a standard diet, group A received a low calcium diet (calcium content 30 per cent of the standard diet) for 6 weeks, and the other two groups were fed a low calcium diet for 3 weeks and then a standard diet without IF (group B) or with IF (group C) for 3 weeks. In addition, distilled water was provided for all groups. The effects of IF on mandibular size and bone mineral content were investigated, using lateral cephalometric analysis and peripheral quantitative computed tomography (pQCT). For mandibular length, the control group showed a significantly higher value than groups A and B (P < 0.01, P < 0.05, respectively), while group C demonstrated a significantly higher value than group A (P < 0.01). In addition, the control group and group C showed significantly higher values for mandibular ramus height than group A (P < 0.01). However, bone mineral density in trabecular bone was significantly higher in the control group than in the other groups (P < 0.01) and bone mineral density in cortical bone was significantly higher in the control group than groups A, B and C (P < 0.01, P < 0.01, P < 0.05, respectively). Bone mineral density in both trabecular and cortical bone was significantly higher in group C than in groups A and B (P < 0.01, P < 0.05, respectively). These results indicate that complete recovery from calcium deficiency to the level of the control group may not be attainable, even though IF enhances calcium absorption to act on bone cells and promote bone construction. The importance of calcium intake in the early stages of development was confirmed. These findings also suggest an effect of IF on jaw bone structure.

The Endo-Distractor for preimplant mandibular regeneration.

PubMed

Krenkel, C; Grunert, I

2009-02-01

A simple practical device for a new technique of vertical distraction osteogenesis was developed. The Endo-Distractor Krenkel was originally intended for the anterior regeneration of highly atrophic mandibles. The Endo-Distractor features several novelties. Placement is made intraosseously in the basal cortical bone. The distraction screw length may be adapted to the depth of chin soft tissues. The quality of anchorage in the basal cortical bone guarantees the stability of the distraction vector. The endobuccal emergence is that of an artificial crown, and does not cause any patient discomfort. The device can easily be removed without secondary surgery. All kinds of implants may be placed after the retention time. This study's objective was to evaluate the use of the Endo-Distractor Krenkel in edentulous patients with highly atrophic mandibles. This new device was used on 18 patients, between January 2000 and September 2004, who were then followed-up for at least 36 months. Mandibular atrophy was measured with a lateral cephalogram, then classified according to Atwood's modified classification. The studied criteria included the amplitude of distraction, its duration, the distractor's lingual tilt, the number and outcome of implants, and complications. The sex ratio was 17 female for one male patient. The mean patient age was 56 years (43 to 66 years). The mean distraction amplitude was 11.3mm (8 to 14 mm). The mean retention time was 186.8 days (37 to 309 days). The distractor's mean lingual tilt was 4.3 degrees (0 to 23 degrees ). Two mandibular fractures occurred 6 weeks after placing the Endo-Distractor. The first one was treated medically, and the second one required removing the Endo-Distractor and osteosynthesis. An average of four interforaminal implants were placed for a total of 24 Brånemark and 51 Straumann implants. Four implants were lost in a patient due to infection. All other implants were osseointegrated. No bone loss was detected at follow-up after functional loading. These results show that alveolar distraction is possible on severely atrophic mandibles. The quality of bone and gum reconstruction is satisfactory both for functional and esthetic results. Surgical difficulty and rate of complications were lower than with conventional distraction techniques.

Treatment of Osteomyelitis: A Case for Disruption of the Affected Adjacent Periosteum.

PubMed

Hudson, John W; Daly, Austin P; Foster, Michael

2017-10-01

To evaluate the response of mandibular osteomyelitis treated by surgical decortication with disruption of the affected adjacent periosteum in concert with long-term targeted antibiotic therapy. The hypothesis is that, by removing the buccal cortical plate and disrupting the hypertrophically inflamed adjacent periosteum, the medullary bone will be brought in contact with bleeding tissue and circulating immunologic factors and antibiotics, which will promote definitive resolution. A retrospective review was conducted of 7 patient charts with associated radiographs from November 2010 to August 2016 treated by the first author at the University of Tennessee Medical Center (Knoxville, TN). Patients with chronic suppurative or nonsuppurative osteomyelitis of the mandible without condylar involvement or pathologic fracture were selected and treated with decortication with periosteal disruption in combination with long-term targeted antibiotic therapy. Seven patients (3 women and 4 men; mean age, 60 yr) underwent decortication with periosteal disruption of the affected area and received at least 6 weeks of targeted intravenous antibiotics. Computed tomography was performed preoperatively and a repeat study was performed after completion of antibiotics. In each case, post-treatment imaging showed definitive resolution after treatment with decortication in concert with disruption of the inflamed hypertrophic periosteum and intravenous antibiotics. Debridement of the infected cortical bone with restoration of the blood supply through disruption of the adjacent periosteum provided definitive resolution of mandibular osteomyelitis in the 7 patients treated. The hypothesis is that disruption of the affected adjacent periosteum reintroduces an immune-mediated response in concert with improved antibiotic delivery to and penetrance of the diseased mandible, aiding in definitive resolution. Decortication with periosteal disruption allows for preservation of the inferior alveolar nerve, maintains mandibular integrity, and obviates reconstructive surgery. Decortication with disruption of the adjacent periosteum, when combined with targeted antimicrobial therapy, produced definitive resolution of osteomyelitis as shown by postoperative imaging. It is the authors' assertion that not only decortication, but also disruption of the adjacent periosteum in combination with targeted antibiotic therapy should be considered a valid and principal therapeutic option for the surgical treatment of osteomyelitis of the mandible. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Multiple sclerosis masquerading as Alzheimer-type dementia: Clinical, radiological and pathological findings.

PubMed

Tobin, W O; Popescu, B F; Lowe, V; Pirko, I; Parisi, J E; Kantarci, K; Fields, J A; Bruns, M B; Boeve, B F; Lucchinetti, C F

2016-04-01

We report a comprehensive clinical, radiological, neuropsychometric and pathological evaluation of a woman with a clinical diagnosis of AD dementia (ADem), but whose autopsy demonstrated widespread demyelination, without Alzheimer disease (AD) pathology. Initial neuropsychometric evaluation suggested amnestic mild cognitive impairment (aMCI). Serial magnetic resonance images (MRI) images demonstrated the rate of increase in her ventricular volume was comparable to that of 46 subjects with aMCI who progressed to ADem, without accumulating white matter disease. Myelin immunohistochemistry at autopsy demonstrated extensive cortical subpial demyelination. Subpial lesions involved the upper cortical layers, and often extended through the entire width of the cortex. Multiple sclerosis (MS) can cause severe cortical dysfunction and mimic ADem. Cortical demyelination is not well detected by standard imaging modalities and may not be detected on autopsy without myelin immunohistochemistry. © The Author(s), 2015.

Esthetic evaluation of single-tooth implants in the anterior mandible.

PubMed

Hof, Markus; Tepper, Gabor; Koller, Barbara; Krainhöfner, Martin; Watzek, Georg; Pommer, Bernhard

2014-09-01

Single-tooth replacement of anterior mandibular teeth is frequently complicated by insufficient bucco-lingual bone width and limited mesio-distal space available for implant placement. The aim of the present study was to assess implant esthetics in the partially edentulous anterior mandible. Esthetic evaluation of 43 anterior mandibular single-tooth implants in 15 women and 28 men was performed using esthetic indices (PES = Pink Esthetic Score, PI = Papilla Index, SES = Subjective Esthetic Score) as well as subjective patients' Visual Analogue Scale (VAS) ratings. Clinical and radiological parameters (implant and crown dimensions, pocket depth, bleeding on probing, plaque, keratinized mucosa, marginal bone level, and distance to adjacent teeth) were tested for influence. Implant esthetics were judged satisfactory (PES ≤10) in 42% of implants compared with a patient satisfaction rate of 87%. Correlation between objective indices (PES/PI: rs  = 0.62, PES/SES: rs  = -0.73, PI/SES: rs  = -0.48) was highly significant (P ≤ 0.001); however, no association to subjective patients' ratings could be observed. Type of prosthetic restoration (single crown vs. tulip-shaped double crowns), mesio-distal crown width as well as anatomic crown length significantly affected esthetic scores. Patients' judgment, by contrast, could not be associated to any prognostic factor. Subjective patient satisfaction with implant esthetics in the partially edentulous anterior mandible is high, however, remains hard to predict or objectively quantify. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Long-term skeletodental stability of mandibular symphyseal distraction osteogenesis: Tooth-borne vs hybrid distraction appliances.

PubMed

Durham, Julia N; King, John W; Robinson, Quinton C; Trojan, Terry M

2017-03-01

To evaluate and compare the long-term skeletodental stability of mandibular symphyseal distraction osteogenesis (MSDO) achieved with the use of tooth-borne vs. hybrid distraction appliances. Posttreatment and follow-up orthodontic records were collected for 33 patients. The 14 patients who underwent distraction with a tooth-borne appliance had a mean follow-up of 5.08 years. The 19 patients who underwent distraction with a hybrid appliance had a mean follow-up of 6.07 years. Records included intraoral photographs, study models, postero-anterior cephalometric radiographs, and lateral cephalometric radiographs. Total changes of 16 measurements were analyzed to compare patients who underwent the tooth-borne vs. the hybrid distraction. Both groups shared several similar and significant (P < .05) changes from posttreatment to follow-up records. Cast analysis showed a decrease in intercanine width and arch length and an increase in irregularity index. The postero-anterior cephalometric radiograph showed an increase in the width of the interincisal apices. The lateral cephalometric radiograph showed a decrease in the MP-L1 angle. The only statistically significant difference between the two appliances was the intercentral incisor contact point. Changes found are consistent with those found in untreated and orthodontically treated individuals over time. The long-term changes in the current patient sample can be determined to be expected and acceptable. MSDO is a viable treatment option with the use of either a hybrid or tooth-borne appliance.

Mesiodistal width of canines: a tool for sex determination.

PubMed

Bakkannavar, Shankar M; Monteiro, Francis N P; Arun, M; Pradeep Kumar, G

2012-01-01

Teeth, in the living as well as the dead, are the most useful objects in the field of forensic investigation. Their ability to survive in situations like mass disasters makes them important tools in victim identification. Though the morphology and structure is similar in both men and women, there are subtle differences. Variation in dental size can give a clue about differences between the sexes. Many authors have measured the crowns of teeth in both men and women and found certain variations. Canines, reported to survive air crash and hurricane disasters, are perhaps the most stable teeth in the oral cavity because of the labiolingual thickness of the crown and the root anchorage in the alveolar process of the jaws. Measurement of mesiodistal width of the mandibular and maxillary canines provides good evidence of sex identification due to dimorphism.

Common errors observed at the American Board of Orthodontics clinical examination.

PubMed

Chung, Chun-Hsi; Tadlock, Larry P; Barone, Nicholas; Pangrazio-Kulbersh, Valmy; Sabott, David G; Foley, Patrick F; Trulove, Timothy S; Park, Jae Hyun; Dugoni, Steven A

2017-08-01

The American Board of Orthodontics has developed tools to help examinees select patients to be used for the Board examination. The Case Management Form can be used to evaluate aspects of a patient's treatment that cannot be measured by other tools. The Case Management Form is a structured treatment-neutral assessment of orthodontic objectives and outcomes associated with a patient's treatment. Despite the availability of this form, examiners continue to see problems, including lack of attention to finishing details, inappropriate treatment objectives, excessive proclination of mandibular incisors due to treatment mechanics, excessive expansion of mandibular intercanine width, closing skeletal open bite with extrusion of anterior teeth leading to excessive gingival display, and failure to recognize the importance of controlling the eruption or extrusion of molars during treatment. In addition, some examinees exhibit a lack of understanding of proper cephalometric tracing and superimposition techniques, which lead to improper interpretation of cephalometric data and treatment outcomes. Copyright © 2017. Published by Elsevier Inc.

Cephalomteric changes in airway dimensions with twin block therapy in growing Class II patients

PubMed Central

Vinoth, Santhana Krishnan; Thomas, Ashwin Varghese; Nethravathy, Ramya

2013-01-01

Introduction: Myofunctional appliances are commonly used for correction of skeletal Class II malrelationship. These appliances influence craniofacial and nasopharyngeal dimensions. Objectives: The present study was done to evaluate changes in airway with twin block therapy. Materials and Methods: Cephalometric assessment of airway was done in 25 growing children in the age group of 11-13 years with Class II skeletal pattern. All the patients were treated with twin block appliance. Pre and post treatment lateral cephalograms were taken to evaluate the changes in different airway and craniofacial dimensions during the treatment period. The average treatment duration was 14.5 months. Results: Airway: A significant increase was observed in upper and lower pharyngeal width and area of bony nasopharynx. Craniofacial dimension: There was a significant increase in effective mandibular length, ramal length and mandibular plane angle. There was an increase in SNB angle, which resulted in decreased ANB angle. Conclusion: There was a definite improvement in airway dimension following twin block therapy PMID:23946570

Effect of Integration Patterns Around Implant Neck on Stress Distribution in Peri-Implant Bone: A Finite Element Analysis.

PubMed

Han, Jingyun; Sun, Yuchun; Wang, Chao

2017-08-01

To investigate the biomechanical performance of different osseointegration patterns between cortical bone and implants using finite element analysis. Fifteen finite element models were constructed of the mandibular fixed prosthesis supported by implants. Masticatory loads (200 N axial, 100 N oblique, 40 N horizontal) were applied. The cortical bone/implant interface was divided equally into four layers: upper, upper-middle, lower-middle, and lower. The bone stress and implant displacement were calculated for 5 degrees of uniform integration (0, 20%, 40%, 60%, and 100%) and 10 integration patterns. The stress was concentrated in the bone margin and gradually decreased as osseointegration progressed, when the integrated and nonintegrated areas were alternated on the bone-implant surface. Compared with full integration, the integration of only the lower-middle layer or lower half layers significantly decreased von Mises, tensile, and compressive stresses in cortical bone under oblique and horizontal loads, and these patterns did not induce higher stress in the cancellous bone. For the integration of only the upper or upper-middle layer, stress in the cortical and cancellous bones significantly increased and was considerably higher than in the case of nonintegration. In addition, the maximum stress in the cortical bone was sensitive to the quantity of integrated nodes at the bone margin; lower quantity was associated with higher stress. There was no significant difference in the displacement of implants among 15 models. Integration patterns of cortical bone significantly affect stress distribution in peri-implant bone. The integration of only the lower-middle or lower half layers helps to increase the load-bearing capacity of peri-implant bone and decrease the risk of overloading, while upper integration may further increase the risk of bone resorption. © 2016 by the American College of Prosthodontists.

Multilevel principal component analysis (mPCA) in shape analysis: A feasibility study in medical and dental imaging.

PubMed

Farnell, D J J; Popat, H; Richmond, S

2016-06-01

Methods used in image processing should reflect any multilevel structures inherent in the image dataset or they run the risk of functioning inadequately. We wish to test the feasibility of multilevel principal components analysis (PCA) to build active shape models (ASMs) for cases relevant to medical and dental imaging. Multilevel PCA was used to carry out model fitting to sets of landmark points and it was compared to the results of "standard" (single-level) PCA. Proof of principle was tested by applying mPCA to model basic peri-oral expressions (happy, neutral, sad) approximated to the junction between the mouth/lips. Monte Carlo simulations were used to create this data which allowed exploration of practical implementation issues such as the number of landmark points, number of images, and number of groups (i.e., "expressions" for this example). To further test the robustness of the method, mPCA was subsequently applied to a dental imaging dataset utilising landmark points (placed by different clinicians) along the boundary of mandibular cortical bone in panoramic radiographs of the face. Changes of expression that varied between groups were modelled correctly at one level of the model and changes in lip width that varied within groups at another for the Monte Carlo dataset. Extreme cases in the test dataset were modelled adequately by mPCA but not by standard PCA. Similarly, variations in the shape of the cortical bone were modelled by one level of mPCA and variations between the experts at another for the panoramic radiographs dataset. Results for mPCA were found to be comparable to those of standard PCA for point-to-point errors via miss-one-out testing for this dataset. These errors reduce with increasing number of eigenvectors/values retained, as expected. We have shown that mPCA can be used in shape models for dental and medical image processing. mPCA was found to provide more control and flexibility when compared to standard "single-level" PCA. Specifically, mPCA is preferable to "standard" PCA when multiple levels occur naturally in the dataset. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Simple bone cyst of mandible mimicking periapical cyst.

PubMed

Hs, Charan Babu; Rai, Bhagawan Das; Nair, Manju A; Astekar, Madhusudan S

2012-05-29

Simple bone cysts (SBC) are pseudocysts occurring less commonly in the maxillofacial region. The uncertain and unclear etiopathogenesis led to numerous synonyms to refer this particular cyst. These cysts are devoid of an epithelial lining and are usually empty or contain blood or straw-colored fluid. In jaws initially it mimics a periapical cyst and later can lead to cortical bone expansion warranting for radical approach, which is seldom required. SBC is predominantly diagnosed in first two decades of life. Here we report a case of solitary bone cyst mimicking a periapical cyst of a mandibular molar in a 37-year-old patient.

Site-Specific Advantages in Skeletal Geometry and Strength at the Proximal Femur and Forearm in Young Female Gymnasts

PubMed Central

Dowthwaite, Jodi N.; Rosenbaum, Paula F.; Scerpella, Tamara A.

2012-01-01

Purpose We evaluated site-specific skeletal adaptation to loading during growth,comparing radius (RAD) and femoral neck (FN) DXA scans in young female gymnasts (GYM) and non-gymnasts (NON). Methods Subjects from an ongoing longitudinal study (8-26 yrs old) underwent annual DXA scans (proximal femur, forearm, total body) and anthropometry, completing maturity and physical activity questionnaires. This cross-sectional analysis used the most recent data meeting the following criteria: gynecological age ≤2.5 yrs post-menarche; GYM annual mean gymnastic exposure ≥5.0 h/wk in the prior year. Bone geometric and strength indices were derived from scans for 173 subjects (8-17 yrs old) via hip structural analysis (femoral narrow neck, NN) and similar radius formulae (1/3 and Ultradistal (UD)). Maturity was coded as M1 (Tanner I breast), M2 (pre-menarche, ≥Tanner II breast) or M3 (post-menarche). ANOVA and chi square compared descriptive data. Two factor ANCOVA adjusted for age, height, total body non-bone lean mass and percent body fat; significance was tested for main effects and interactions between gymnastic exposure and maturity. Results At the distal radius, GYM means were significantly greater than NON means for all variables (p<0.05). At the proximal femur, GYM exhibited narrower periosteal and endosteal dimensions, but greater indices of cortical thickness, BMC, aBMD and section modulus, with lower buckling ratio (p <0.05). However, significant interactions between maturity and loading were detected for the following: 1) FN bone mineral content (BMC), NN buckling ratio (GYM BMC advantages only in M1 and M3; for BMC and buckling ratio, M1 advantages were greatest; 2) 1/3 radius BMC, width, endosteal diameter, cortical cross-sectional area, section modulus (GYM advantages primarily post-menarche); 3) UD radius BMC and axial compressive strength (GYM advantages were larger with greater maturity, greatest post-menarche). Conclusions Maturity-specific comparisons suggested site-specific skeletal adaptation to loading during growth, with greater advantages at the radius versus the proximal femur. At the radius, GYM advantages included greater bone width, cortical cross-sectional area and cortical thickness; in contrast, at the femoral neck, GYM bone tissue cross-sectional area and cortical thickness were greater, but bone width was narrower than in NON. Future longitudinal analyses will evaluate putative maturity-specific differences. PMID:22342799

Three-dimensional computer-assisted study model analysis of long-term oral-appliance wear. Part 1: Methodology.

PubMed

Chen, Hui; Lowe, Alan A; de Almeida, Fernanda Riberiro; Wong, Mary; Fleetham, John A; Wang, Bangkang

2008-09-01

The aim of this study was to test a 3-dimensional (3D) computer-assisted dental model analysis system that uses selected landmarks to describe tooth movement during treatment with an oral appliance. Dental casts of 70 patients diagnosed with obstructive sleep apnea and treated with oral appliances for a mean time of 7 years 4 months were evaluated with a 3D digitizer (MicroScribe-3DX, Immersion, San Jose, Calif) compatible with the Rhinoceros modeling program (version 3.0 SR3c, Robert McNeel & Associates, Seattle, Wash). A total of 86 landmarks on each model were digitized, and 156 variables were calculated as either the linear distance between points or the distance from points to reference planes. Four study models for each patient (maxillary baseline, mandibular baseline, maxillary follow-up, and mandibular follow-up) were superimposed on 2 sets of reference points: 3 points on the palatal rugae for maxillary model superimposition, and 3 occlusal contact points for the same set of maxillary and mandibular model superimpositions. The patients were divided into 3 evaluation groups by 5 orthodontists based on the changes between baseline and follow-up study models. Digital dental measurements could be analyzed, including arch width, arch length, curve of Spee, overbite, overjet, and the anteroposterior relationship between the maxillary and mandibular arches. A method error within 0.23 mm in 14 selected variables was found for the 3D system. The statistical differences in the 3 evaluation groups verified the division criteria determined by the orthodontists. The system provides a method to record 3D measurements of study models that permits computer visualization of tooth position and movement from various perspectives.

The combination of a histogram-based clustering algorithm and support vector machine for the diagnosis of osteoporosis.

PubMed

Kavitha, Muthu Subash; Asano, Akira; Taguchi, Akira; Heo, Min-Suk

2013-09-01

To prevent low bone mineral density (BMD), that is, osteoporosis, in postmenopausal women, it is essential to diagnose osteoporosis more precisely. This study presented an automatic approach utilizing a histogram-based automatic clustering (HAC) algorithm with a support vector machine (SVM) to analyse dental panoramic radiographs (DPRs) and thus improve diagnostic accuracy by identifying postmenopausal women with low BMD or osteoporosis. We integrated our newly-proposed histogram-based automatic clustering (HAC) algorithm with our previously-designed computer-aided diagnosis system. The extracted moment-based features (mean, variance, skewness, and kurtosis) of the mandibular cortical width for the radial basis function (RBF) SVM classifier were employed. We also compared the diagnostic efficacy of the SVM model with the back propagation (BP) neural network model. In this study, DPRs and BMD measurements of 100 postmenopausal women patients (aged >50 years), with no previous record of osteoporosis, were randomly selected for inclusion. The accuracy, sensitivity, and specificity of the BMD measurements using our HAC-SVM model to identify women with low BMD were 93.0% (88.0%-98.0%), 95.8% (91.9%-99.7%) and 86.6% (79.9%-93.3%), respectively, at the lumbar spine; and 89.0% (82.9%-95.1%), 96.0% (92.2%-99.8%) and 84.0% (76.8%-91.2%), respectively, at the femoral neck. Our experimental results predict that the proposed HAC-SVM model combination applied on DPRs could be useful to assist dentists in early diagnosis and help to reduce the morbidity and mortality associated with low BMD and osteoporosis.

Effects of Mandibular Retrusive Deviation on Prefrontal Cortex Activation: A Functional Near-Infrared Spectroscopy Study

PubMed Central

Otsuka, Takero; Yamasaki, Ryuichi; Shimazaki, Tateshi; Sasaguri, Kenichi; Kawata, Toshitsugu

2015-01-01

The objective of this study was to evaluate occlusal condition by assessing brain activity in the prefrontal cortex, which is associated with emotion. Functional near-infrared spectroscopy (fNIRS) was used to detect changes in cerebral blood flow in the prefrontal cortex of 12 healthy volunteers. The malocclusion model was a custom-made splint that forced the mandible into retrusion. A splint with no modification was used as a control. The cortical activation during clenching was compared between the retrusive position condition and the control condition. A visual analog scale score for discomfort was also obtained during clenching and used to evaluate the interaction between fNIRS data and psychiatric changes. Activation of the prefrontal cortex was significantly greater during clenching in the mandibular retrusive condition than during clenching in the control condition. Furthermore, Spearman rank-correlation coefficient revealed a parallel relation between prefrontal cortex activation and visual analog scale score for discomfort. These results indicate that fNIRS can be used to objectively evaluate the occlusal condition by evaluating activity in the prefrontal cortex. PMID:26075235

Effects of mandibular retrusive deviation on prefrontal cortex activation: a functional near-infrared spectroscopy study.

PubMed

Otsuka, Takero; Yamasaki, Ryuichi; Shimazaki, Tateshi; Yoshino, Fumihiko; Sasaguri, Kenichi; Kawata, Toshitsugu

2015-01-01

The objective of this study was to evaluate occlusal condition by assessing brain activity in the prefrontal cortex, which is associated with emotion. Functional near-infrared spectroscopy (fNIRS) was used to detect changes in cerebral blood flow in the prefrontal cortex of 12 healthy volunteers. The malocclusion model was a custom-made splint that forced the mandible into retrusion. A splint with no modification was used as a control. The cortical activation during clenching was compared between the retrusive position condition and the control condition. A visual analog scale score for discomfort was also obtained during clenching and used to evaluate the interaction between fNIRS data and psychiatric changes. Activation of the prefrontal cortex was significantly greater during clenching in the mandibular retrusive condition than during clenching in the control condition. Furthermore, Spearman rank-correlation coefficient revealed a parallel relation between prefrontal cortex activation and visual analog scale score for discomfort. These results indicate that fNIRS can be used to objectively evaluate the occlusal condition by evaluating activity in the prefrontal cortex.

Changes in mandibular dimensions during the mediaeval to post-mediaeval transition in London: a possible response to decreased masticatory load.

PubMed

Rando, Carolyn; Hillson, Simon; Antoine, Daniel

2014-01-01

Biomechanical forces, such as those produced during mastication, are considered a primary agent in stimulating craniofacial growth and development. There appears to be a strong connection between the strength of the masticatory muscles and the dimensions of the craniofacial complex, with changes in biomechanical force and muscular strength influencing and altering the underlying bony tissues. This is markedly apparent in the mandible and it is possible to infer that changes to mandibular form are due in part to dietary changes. This study aims to investigate this idea by using an archaeological sample from a period that experienced important dietary changes as a result of the Industrial Revolution. 279 skeletons from the mediaeval and post-mediaeval periods in London were selected for analysis, and a detailed metric examination of each mandible was carried out. Males and females were analysed separately and statistically significant reductions were observed in nearly all post-mediaeval measurements. This effect was most pronounced in the areas of the mandible associated with masticatory muscles attachment, including the gonial angle, ramus height and width, bi-gonial breadth and bi-condylar breadth. These recorded changes in mandibular morphology of mediaeval and post-mediaeval Londoners are most likely the result of a shift in diet (and associated decrease in masticatory function) observed in the period surrounding the Industrial Revolution. Copyright © 2013 Elsevier Ltd. All rights reserved.

Volumetric analysis of chin and mandibular retromolar region as donor sites for cortico-cancellous bone blocks.

PubMed

Zeltner, Marco; Flückiger, Laura B; Hämmerle, Christoph H F; Hüsler, Jürg; Benic, Goran I

2016-08-01

To test whether the mandibular retromolar region renders different results from the chin region with respect to the amount of bone available for the harvesting of block grafts. Sixty cone beam computed tomography (CBCT) scans of mandibles of adult patients without pathologic findings in the chin and retromolar region were included. According to the number of mandibular teeth, 20 CBCT data sets were allocated to each of the following groups: group M1: dentition 36-46; group M2: dentition 37-47; and group M3: dentition 38-48. For the potential donor sites in the chin and the retromolar regions, the volume (VChin , VRetro ), the length (LChin , LRetro ), the height (HChin , HRetro ) and the width (HChin , HRetro ) were assessed using a computer software. Moreover, the chin was examined for the presence and the localization of the mandibular incisive canal. To compare the donor sites in the chin and in the retromolar regions, the quotients VRetro /VChin , LRetro /LChin , HRetro /HChin and WRetro /WChin were calculated and tested using the Wilcoxon signed-rank test or the sign test. The mean bone volume VChin measured 3.5 ± 1.3 cm(3) (SD), whereas the overall VRetro amounted to 1.8 ± 1.1 cm(3) (SD). VRetro amounted to 2.6 ± 1.4 cm(3) (SD) in the group M1, 1.8 ± 0.5 cm(3) in the group M2 and 1.0 ± 0.4 cm(3) in the group M3. For the group M1, VRetro /VChin measured 82 ± 39% (P = 0.036). VRetro /VChin reached 57 ± 20% in the group M2 and 32 ± 12% in the group M3 (P < 0.001). The mandibular incisive canal was detected in 97% of the CBCT scans. The distance between the mandibular incisive canal and the apices of the central incisors measured 10.5 ± 3.5 mm. The amount of bone available for the harvesting of cortico-cancellous blocks in the chin region was superior in comparison with the mandibular retromolar region. In the absence of the second and the third molars, the amount of bone harvestable in the retromolar region reached approximately 80% of the bone volume available in the chin region. In the majority of the cases, the mandibular incisive canal was detected within the donor site in the chin region. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Three-dimensional evaluation of upper airway following rapid maxillary expansion: a CBCT study.

PubMed

El, Hakan; Palomo, Juan Martin

2014-03-01

To evaluate, by using cone beam computed tomography, the skeletal, dental, oropharyngeal (OP) airway volume, and nasal passage (NP) volume changes that occur after rapid maxillary expansion (RME). Two groups were selected, each with 35 patients (15 males, 20 females), an RME group (mean age, 14.02 ± 1.46 years) and a control group (mean age, 14.10 ± 1.44 years). The RME group consisted of patients with maxillary constriction who were treated with Hyrax palatal expanders, and the control group comprised age- and sex-matched patients who underwent comprehensive orthodontic treatment without the use of a rapid maxillary expander. All of the transverse skeletal (medial orbital width, lateral nasal width, maxillary width, and mandibular width) and interdental (intermolar, interpremolar, and intercanine) parameters were significantly enlarged in the RME group. A statistically significant increase in airway variables was seen in both groups between pretreatment (T0) and final records (T1). The mean increase of NP airway volume for the RME group (1719.9 ± 1510.7 mm(3)) was twofold compared with the control group (813.6 ± 1006.7 mm(3)), and no intergroup significant difference was found for the OP volume. Rapid maxillary expansion creates a significant increase in nasal passage airway volume but no significant change in the oropharyngeal airway volume.

Comparison of Neck Screw and Conventional Fixation Techniques in Mandibular Condyle Fractures Using 3-Dimensional Finite Element Analysis.

PubMed

Conci, Ricardo Augusto; Tomazi, Flavio Henrique Silveira; Noritomi, Pedro Yoshito; da Silva, Jorge Vicente Lopes; Fritscher, Guilherme Genehr; Heitz, Claiton

2015-07-01

To compare the mechanical stress on the mandibular condyle after the reduction and fixation of mandibular condylar fractures using the neck screw and 2 other conventional techniques according to 3-dimensional finite element analysis. A 3-dimensional finite element model of a mandible was created and graphically simulated on a computer screen. The model was fixed with 3 different techniques: a 2.0-mm plate with 4 screws, 2 plates (1 1.5-mm plate and 1 2.0-mm plate) with 4 screws, and a neck screw. Loads were applied that simulated muscular action, with restrictions of the upper movements of the mandible, differentiation of the cortical and medullary bone, and the virtual "folds" of the plates and screws so that they could adjust to the condylar surface. Afterward, the data were exported for graphic visualization of the results and quantitative analysis was performed. The 2-plate technique exhibited better stability in regard to displacement of fractures, deformity of the synthesis materials, and minimum and maximum tension values. The results with the neck screw were satisfactory and were similar to those found when a miniplate was used. Although the study shows that 2 isolated plates yielded better results compared with the other groups using other fixation systems and methods, the neck screw could be an option for condylar fracture reduction. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Biomechanical analysis comparing natural and alloplastic temporomandibular joint replacement using a finite element model.

PubMed

Mesnard, Michel; Ramos, Antonio; Ballu, Alex; Morlier, Julien; Cid, M; Simoes, J A

2011-04-01

Prosthetic materials and bone present quite different mechanical properties. Consequently, mandible reconstruction with metallic materials (or a mandible condyle implant) modifies the physiologic behavior of the mandible (stress, strain patterns, and condyle displacements). The changing of bone strain distribution results in an adaptation of the temporomandibular joint, including articular contacts. Using a validated finite element model, the natural mandible strains and condyle displacements were evaluated. Modifications of strains and displacements were then assessed for 2 different temporomandibular joint implants. Because materials and geometry play important key roles, mechanical properties of cortical bone were taken into account in models used in finite element analysis. The finite element model allowed verification of the worst loading configuration of the mandibular condyle. Replacing the natural condyle by 1 of the 2 tested implants, the results also show the importance of the implant geometry concerning biomechanical mandibular behavior. The implant geometry and stiffness influenced mainly strain distribution. The different forces applied to the mandible by the elevator muscles, teeth, and joint loads indicate that the finite element model is a relevant tool to optimize implant geometry or, in a subsequent study, to choose a more suitable distribution of the screws. Bone screws (number and position) have a significant influence on mandibular behavior and on implant stress pattern. Stress concentration and implant fracture must be avoided. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Radiological changes with magnetic resonance imaging and computed tomography after irradiating minipig mandibles: The role of T2-SPIR mixed signal intensities in the detection of osteoradionecrosis.

PubMed

Poort, Lucas J; Postma, Alida A; Stadler, Annika A R; Böckmann, Roland A; Hoebers, Frank J; Kessler, Peter A W H

2017-05-01

Radiotherapy in the head and neck can induce several radiologically detectable changes in bone, osteoradionecrosis (ORN) among them. The purpose is to investigate radiological changes in mandibular bone after irradiation with various doses with and without surgery and to determine imaging characteristics of radiotherapy and ORN in an animal model. Sixteen Göttingen minipigs were divided into groups and were irradiated with two fractions with equivalent doses of 0, 25, 50 and 70 Gray. Thirteen weeks after irradiation, left mandibular teeth were removed and dental implants were placed. CT-scans and MR-imaging were made before irradiation and twenty-six weeks after. Alterations in the bony structures were recorded on CT-scan and MR-imaging and scored by two head-neck radiologists. Increased signal changes on MR-imaging were associated with higher radiation doses. Two animals developed ORN clinically. Radiologically mixed signal intensities on T2-SPIR were seen. On CT-scans cortical destruction was found in three animals. Based on imaging, three animals were diagnosed with ORN. Irradiation of minipig mandibles with various doses induced damages of the mandibular bone. Imaging with CT-scan and MR-imaging showed signal and structural changes that can be interpreted as prolonged and insufficient repair of radiation induced bone damages. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Correlation between the thickness of the crestal and buccolingual cortical bone at varying depths and implant stability quotients

PubMed Central

Chatvaratthana, Kanthanat; Thaworanunta, Sita; Seriwatanachai, Dutmanee; Wongsirichat, Natthamet

2017-01-01

Background/purpose Resonance frequency analysis (RFA) is clinically used in dentistry to access the stiffness of dental implants in surrounding bone. However, the clear advantages and disadvantages of this method are still inconclusive. The aim of this study was to investigate and compare implant stability quotient (ISQ) values obtained from RFA with parameters obtained from a cone beam computed tomography (CBCT) scan of the same region. Materials and methods Nineteen implants (Conelog) were inserted in the posterior maxillary and mandibular partially edentulous regions of 16 patients. At the time of implant placement, the ISQ values were obtained using RFA (Osstell). CBCT was used to measure the thickness of the crestal, cortical, buccolingual cortical, and cancellous bone at 3, 6, and 9 mm below the crestal bone level, as indicated by radiographic markers. The ratio of the thickness of the cortical to cancellous bone at varying depths was also calculated and classified into 4 groups (Group 1–4). Results There was a strong correlation between the crestal cortical bone thickness and ISQ values (P<0.001). The thickness of the buccolingual cortical bone and ratio of the cortical to cancellous bone thickness at 3 mm were significantly related to the ISQ (P = 0.018 and P = 0.034, respectively). Furthermore, the ISQs in Group 1 were the highest compared with those in Group 2 and Group 3, whereas the CBCT parameters at 6 and 9 mm did not have any specific correlation with the ISQ values. Conclusion This study showed that the ISQ values obtained from RFA highly correlated with the quantity and quality of bone 3 mm below the crestal bone level. The correlation between the ISQ and bone surrounding the implant site was dependent on the depth of measurement. Therefore, RFA can help to predict the marginal bone level, as confirmed in this study. PMID:29281715

Orthodontically induced eruption of a horizontally impacted maxillary central incisor.

PubMed

Rizzatto, Susana Maria Deon; de Menezes, Luciane Macedo; Allgayer, Susiane; Batista, Eraldo Luiz; Freitas, Maria Perpétua Mota; Loro, Raphael Carlos Drumond

2013-07-01

This case report presents the clinical features and periodontal findings in a patient with a horizontally impacted maxillary central incisor that had been exposed and aligned after a closed-eruption surgical technique. By combining 3 treatment stages-maxillary expansion, crown exposure surgery, and induced eruption-the horizontally impacted incisor was successfully moved into proper position. The patient finished treatment with a normal and stable occlusion between the maxillary and mandibular arches, and an adequate width of attached gingiva, even in the area surrounding the crown. The 5-year follow-up of stability and periodontal health demonstrated esthetic and functional outcomes after orthodontically induced tooth eruption. Clinical evaluation showed that the treated central incisor had periodontal clinical variables related to visible plaque, bleeding on probing, width of attached gingiva, and crown length that resembled the contralateral incisor. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Spatial variation in mandibular bone elastic modulus and its effect on structural bending stiffness: A test case using the Taï Forest monkeys.

PubMed

Le, Kim N; Marsik, Matthew; Daegling, David J; Duque, Ana; McGraw, William Scott

2017-03-01

We investigated how heterogeneity in material stiffness affects structural stiffness in the cercopithecid mandibular cortical bone. We assessed (1) whether this effect changes the interpretation of interspecific structural stiffness variation across four primate species, (2) whether the heterogeneity is random, and (3) whether heterogeneity mitigates bending stress in the jaw associated with food processing. The sample consisted of Taï Forest, Cote d'Ivoire, monkeys: Cercocebus atys, Piliocolobus badius, Colobus polykomos, and Cercopithecus diana. Vickers indentation hardness samples estimated elastic moduli throughout the cortical bone area of each coronal section of postcanine corpus. For each section, we calculated maximum area moment of inertia, I max (structural mechanical property), under three models of material heterogeneity, as well as spatial autocorrelation statistics (Moran's I, I MORAN ). When the model considered material stiffness variation and spatial patterning, I max decreased and individual ranks based on structural stiffness changed. Rank changes were not significant across models. All specimens showed positive (nonrandom) spatial autocorrelation. Differences in I MORAN were not significant among species, and there were no discernable patterns of autocorrelation within species. Across species, significant local I MORAN was often attributed to proximity of low moduli in the alveolar process and high moduli in the basal process. While our sample did not demonstrate species differences in the degree of spatial autocorrelation of elastic moduli, there may be mechanical effects of heterogeneity (relative strength and rigidity) that do distinguish at the species or subfamilial level (i.e., colobines vs. cercopithecines). The potential connections of heterogeneity to diet and/or taxonomy remain to be discovered. © 2016 Wiley Periodicals, Inc.

Determination of spatial distribution of increase in bone temperature during drilling by infrared thermography: preliminary report.

PubMed

Augustin, Goran; Davila, Slavko; Udiljak, Toma; Vedrina, Denis Stjepan; Bagatin, Dinko

2009-05-01

During the drilling of the bone, the temperature could increase above 47 degrees C and cause irreversible osteonecrosis. The spatial distribution of increase in bone temperature could only be presumed using several thermocouples around the drilling site. The aim of this study was to use infrared thermographic camera for determination of spatial distribution of increase in bone temperature during drilling. One combination of drill parameters was used (drill diameter 4.5 mm; drill speed 1,820 rpm; feed-rate 84 mm/min; drill point angle 100 degrees) without external irrigation on room temperature of 26 degrees C. The increase in bone temperature during drilling was analyzed with infrared thermographic camera in two perpendicular planes. Thermographic pictures were taken before drilling, during drilling with measurement of maximal temperature values and after extraction of the drill from the bone. The thermographic picture shows that the increase in bone temperature has irregular shape with maximal increase along cortical bone, which is the most compact component of the bone. The width of this area with the temperature above critical level is three times broader than the width of cortical bone. From the front, the distribution of increase in bone temperature follows the form of the cortical bone (segment of a ring), which is the most compact part and causes the highest resistance to drilling and subsequent friction. Thermography showed that increase in bone temperature spreads through cortical bone, which is the most compact and dense part, and generates highest frictional heat during drilling. The medullar cavity, because of its gelatinous structure, contributes only to thermal dissipation.

Age-related effects in the neocortical organization of chimpanzees: gray and white matter volume, cortical thickness, and gyrification.

PubMed

Autrey, Michelle M; Reamer, Lisa A; Mareno, Mary Catherine; Sherwood, Chet C; Herndon, James G; Preuss, Todd; Schapiro, Steve J; Hopkins, William D

2014-11-01

Among primates, humans exhibit the most profound degree of age-related brain volumetric decline in particular regions, such as the hippocampus and the frontal lobe. Recent studies have shown that our closest living relatives, the chimpanzees, experience little to no volumetric decline in gray and white matter over the adult lifespan. However, these previous studies were limited with a small sample of chimpanzees of the most advanced ages. In the present study, we sought to further test for potential age-related decline in cortical organization in chimpanzees by expanding the sample size of aged chimpanzees. We used the BrainVisa software to measure total brain volume, gray and white matter volumes, gray matter thickness, and gyrification index in a cross-sectional sample of 219 captive chimpanzees (8-53 years old), with 38 subjects being 40 or more years of age. Mean depth and cortical fold opening of 11 major sulci of the chimpanzee brains were also measured. We found that chimpanzees showed increased gyrification with age and a cubic relationship between age and white matter volume. For the association between age and sulcus depth and width, the results were mostly non-significant with the exception of one negative correlation between age and the fronto-orbital sulcus. In short, results showed that chimpanzees exhibit few age-related changes in global cortical organization, sulcus folding and sulcus width. These findings support previous studies and the theory that the age-related changes in the human brain is due to an extended lifespan. Copyright © 2014 Elsevier Inc. All rights reserved.

[Stress analysis of femoral stems in cementless total hip arthroplasty by two-dimensional finite element method using boundary friction layer].

PubMed

Oomori, H; Imura, S; Gesso, H

1992-04-01

To develop stem design achieving primary fixation of stems and effective load transfer to the femur, we studied stress analysis of stems in cementless total hip arthroplasty by two-dimensional finite element method using boundary friction layer in stem-bone interface. The results of analyses of stem-bone interface stresses and von Mises stresses at the cortical bones indicated that ideal stem design features would be as follows: 1) Sufficient length, with the distal end extending beyond the isthmus region. 2) Maximum possible width, to contact the cortical bones in the isthmus region. 3) No collars but a lateral shoulder at the proximal portion. 4) A distal tip, to contact the cortical bones at the distal portion.

Simple bone cyst of mandible mimicking periapical cyst

PubMed Central

HS, Charan Babu; Rai, Bhagawan Das; Nair, Manju A.; Astekar, Madhusudan S.

2012-01-01

Simple bone cysts (SBC) are pseudocysts occurring less commonly in the maxillofacial region. The uncertain and unclear etiopathogenesis led to numerous synonyms to refer this particular cyst. These cysts are devoid of an epithelial lining and are usually empty or contain blood or straw-colored fluid. In jaws initially it mimics a periapical cyst and later can lead to cortical bone expansion warranting for radical approach, which is seldom required. SBC is predominantly diagnosed in first two decades of life. Here we report a case of solitary bone cyst mimicking a periapical cyst of a mandibular molar in a 37-year-old patient. PMID:24765458

No differences in calcium-binding protein immunoreactivity in the posterior cingulate and visual cortex: schizophrenia and controls.

PubMed

Wheeler, David G; Dixon, Gavin; Harper, Clive G

2006-06-01

Schizophrenia-specific alterations in the densities of interneurons immunoreactive (ir) to the calcium binding proteins are reported for several cortical regions. However, no reported studies have searched for such differences within the posterior cingulate cortex using antibodies to a specific calcium binding protein, calbindin (Cb). Compare the (a) relative density of Cb-ir neurons (ratio of labeled neurons to total neurons), (b) relative width of cortical layers II/III and (c) somal areas of Cb-ir neurons in people with schizophrenia and non-psychiatric age-, gender- and postmortem index-matched controls (9 per group). Tissue from Brodmann's area (BA) 30 and 23 and an internal control region, the visual cortex (BA 18) were labeled with polyclonal Cb antibodies then Nissl counter-stained. Cb-ir neurons as well as counter-stained neurons with clearly visible nucleoli were plotted and counted within their area 1 and laminar boundaries. No qualitative or statistical differences in the relative density of Cb-ir neurons were observed. A trend towards a significant effect was detected in BA 30, the relative density of Cb-ir neurons for controls was greater than for schizophrenics (P=0.0518). There were no significant differences in the relative cortical widths or somal areas. The data from this study suggest that the posterior cingulate cortex may not be involved in schizophrenia, at least not as far as Cb-ir neurons are concerned.

Assessing bone volume for orthodontic miniplate fixation below the maxillary frontal process.

PubMed

Präger, T M; Brochhagen, H G; Mischkowski, R; Jost-Brinkmann, P-G; Müller-Hartwich, R

2014-09-01

The maxillary bone below the frontal process is used for orthodontic anchorage; indications have included skeletally anchored protraction of the maxilla for treating Class III malocclusions or the intrusion of teeth in patients with a deep bite. This study was conducted to assess the condition of bone before cortically implanting miniplates in that area of the maxilla. A total of 51 thin-sliced computed tomography scans of 51 fully-dentate adult patients (mean age 24.0 ± 8.1 years; 27 men and 24 women) obtained prior to third-molar osteotomy were evaluated. Study parameters included total bone thickness, thickness of the facial cortical plate, and width of the nasal maxillary buttress. All these parameters were measured at different vertical levels. The bone volume adjacent to the piriform aperture was most pronounced at the basal level and decreased progressively toward more cranial levels. The basal bone structure had a mean total thickness of 7.8 mm, facial cortical plate thickness of 1.9 mm, and nasal maxillary buttress width of 9.2 mm. At 16 mm cranial to the aperture base, these values fell to 5.6 mm, 1.3 mm, and 5.8 mm, respectively. These bone measurements suggest that screws 7 mm in length can be inserted at the base level of the piriform aperture and screws 5 mm long at the cranial end of the bone.

[A case of the Hallermann-Streiff syndrome].

PubMed

Higashi, M; Hara, M; Michimata, H; Nishimura, K; Kurihara, Y

1990-01-01

The Hallermann-Streiff Syndrome has been characterized and established according to 7 positive and 5 negative signs, which were described by François. We encountered an 11 year, 5 months old boy who had 7 positive symptoms of this syndrome in our clinic. In this study, we reported on this typical patient focusing on his dental view. 1) Prolonged retention of the primary teeth which involved microdontia were noted. Congenitally missing teeth were also seen. 2) The occlusal relationship indicated open bite, and also the mandibular function was impaired. 3) The measurements of the length and width of the dental arch were smaller than that of a normal subject, and the dental arch of the maxilla was V-shaped. 4) According to X-ray cephalometric analysis, (a) the dental calculus and the alveolar bone absorption were very evident. (b) abnormal morphologic of the glenoid fossa, mandibulars condyle and the neck of mandibula were seen. These conditions were very evident on the left side. 5) The growth obstade of the maxilla and mandibla and the left shift of the mandible were found. 6) According to histological study, enamel hypoplasia was noted.

Postoperative evaluation of palatoplasty using the modified Kaplan method.

PubMed

Isago, Tsukasa; Nozaki, Motohiro; Honda, Takashi; Kikuchi, Yuji

2005-01-01

Bilateral buccal mucosal flaps were used for a pushback operation of the nasal mucosa as well as the oral mucosa. Two flaps from the buccal mucosal areas were inserted into the nasal mucosal raw surface at the hard and soft palatal border to achieve nasal mucosal pushback. Forty-four children with cleft palates were retrospectively studied to investigate the velopharyngeal function, articulation, and craniofacial morphology following primary palatoplasty using the modified Kaplan method. 72.7% showed good velopharyngeal function. Articulation disorders were found in 26 of the 44 subjects (59.1%). A craniofacial morphological analysis revealed no major changes in the SNA (sella-nasion point A angle) and SNB (sella-nasion point B angle) and no cases of a marked loss of maxillary mandibular balance. In addition, no significant differences were observed in the maxillary length and width. The results of these palatoplasties by the modified Kaplan method indicated that the use of bilateral buccal mucosal flaps for the pushback of the nasal mucosa was effective in preventing the contraction of the maxillary and mandibular corpal lengths.

Three-dimensional evaluation of the relationship between jaw divergence and facial soft tissue dimensions.

PubMed

Rongo, Roberto; Antoun, Joseph Saswat; Lim, Yi Xin; Dias, George; Valletta, Rosa; Farella, Mauro

2014-09-01

To evaluate the relationship between mandibular divergence and vertical and transverse dimensions of the face. A sample was recruited from the orthodontic clinic of the University of Otago, New Zealand. The recruited participants (N  =  60) were assigned to three different groups based on the mandibular plane angle (hyperdivergent, n  =  20; normodivergent, n  =  20; and hypodivergent, n  =  20). The sample consisted of 31 females and 29 males, with a mean age of 21.1 years (SD ± 5.0). Facial scans were recorded for each participant using a three-dimensional (3D) white-light scanner and then merged to form a single 3D image of the face. Vertical and transverse measurements of the face were assessed from the 3D facial image. The hyperdivergent sample had a significantly larger total and lower anterior facial height than the other two groups (P < .05), although no difference was found for the middle facial height (P > .05). Similarly, there were no significant differences in the transverse measurements of the three study groups (P > .05). Both gender and body mass index (BMI) had a greater influence on the transverse dimension. Hyperdivergent facial types are associated with a long face but not necessarily a narrow face. Variations in facial soft tissue vertical and transversal dimensions are more likely to be due to gender. Body mass index has a role in mandibular width (GoGo) assessment.

A numerical simulation of the effect of using porous superelastic Nitinol and stiff Titanium fixation hardware on the bone remodeling

NASA Astrophysics Data System (ADS)

Raad, Bahram; Shayesteh Moghaddam, Narges; Elahinia, Mohammad

2016-04-01

The aim of this article is to investigate the effect of two different fixation hardware materials on bone remodeling after a mandibular reconstruction surgery and to restore the mandible's function, healthy appearance, mastication, swallowing, breathing, and speech. The hypothesis is that using fixation hardware with stiffness close to that of the surrounding bone will result in a more successful healing process in the mandible bone. The finite element model includes the material properties and forces of the cancellous bone, cortical bone, ligaments, muscles, and teeth. The reconstruction surgery is modeled by including the fixation hardware and the grafted bone. In the sectioned mandible, to best mimic the geometry of the mandible, two single barrel grafts are placed at the top of each other to form a double barrel graft set. Two different materials were used as the mandibular fixation parts, stiff Ti-6Al-4V, and porous superelastic Nickel-Titanium (NiTi) alloys. A comparison of these two alloys demonstrates that using porous NiTi alloy as the fixation part results in a faster healing pace. Furthermore, the density distribution in the mandibular bone after the healing process is more similar to the normal mandible density distribution. The simulations results indicate that the porous superelastic NiTi fixation hardware transfers and distributes the existing forces on the mandible bone more favorably. The probability of stress shielding and/or stress concentration decrease. This type of fixation hardware, therefore, is more appropriate for mandible bone reconstruction surgery. These predictions are in agreement with the clinical observations.

Free bone graft reconstruction of irradiated facial tissue: Experimental effects of basic fibroblast growth factor stimulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eppley, B.L.; Connolly, D.T.; Winkelmann, T.

1991-07-01

A study was undertaken to evaluate the potential utility of basic fibroblast growth factor in the induction of angiogenesis and osseous healing in bone previously exposed to high doses of irradiation. Thirty New Zealand rabbits were evaluated by introducing basic fibroblast growth factor into irradiated mandibular resection sites either prior to or simultaneous with reconstruction by corticocancellous autografts harvested from the ilium. The fate of the free bone grafts was then evaluated at 90 days postoperatively by microangiographic, histologic, and fluorochrome bone-labeling techniques. Sequestration, necrosis, and failure to heal to recipient osseous margins was observed both clinically and histologically inmore » all nontreated irradiated graft sites as well as those receiving simultaneous angiogenic stimulation at the time of graft placement. No fluorescent activity was seen in these graft groups. In the recipient sites pretreated with basic fibroblast growth factor prior to placement of the graft, healing and reestablishment of mandibular contour occurred in nearly 50 percent of the animals. Active bone formation was evident at cortical margins adjacent to the recipient sites but was absent in the more central cancellous regions of the grafts.« less

Neocortical Maturation during Adolescence: Change in Neuronal Soma Dimension

ERIC Educational Resources Information Center

Rabinowicz, Theodore; Petetot, Jean MacDonald-Comber; Khoury, Jane C.; de Courten-Myers, Gabrielle M.

2009-01-01

During adolescence, cognitive abilities increase robustly. To search for possible related structural alterations of the cerebral cortex, we measured neuronal soma dimension (NSD = width times height), cortical thickness and neuronal densities in different types of neocortex in post-mortem brains of five 12-16 and five 17-24 year-olds (each 2F,…

Canine and Premolar Root Dimensions in Chinese. A Reference for Osteoodontokeratoprosthesis Surgery.

PubMed

Sun, Stella Yue; Yeo, Woon Chee; Tay, Andrew Ban Guan; Tan, Donald Tiang Hwee; Tan, Danny Ben Poon

2018-01-01

Osteoodontokeratoprosthesis (OOKP) surgery is used to restore vision in end-stage corneal disorders, where an autogenous tooth supporting an optical cylinder is implanted through the cornea under a buccal mucosal graft. The ideal tooth for OOKP is a healthy single-rooted permanent tooth with sufficient buccolingual/palatal root diameter to accommodate an optical cylinder. The aim of this study was to determine the buccolingual/palatal diameters of canine and premolar roots in Chinese, for selection of teeth for OOKP surgery. This was an anatomical study on root dimensions of extracted intact teeth. Extracted canine and premolar teeth (excluding maxillary first premolars) were collected and the buccolingual/palatal and mesiodistal diameters of the root at the cervical line and at 2-mm intervals below the cervical line were measured with Vernier calipers. Other measurements included total tooth length, crown buccolingual/palatal diameter, and root length. Mean and minimum buccolingual/palatal root diameters were compiled for each 2-mm interval. A total of 415 extracted teeth (198 male, 217 female) were collected and measured. Recorded dimensions of keratoprostheses in 55 previous OOKP surgeries were used to establish acceptable lamina dimensions to ascertain root size adequacy. Premolars in Chinese female patients were undersized in a small minority. Minimal dimensions of teeth were insufficient if at 6 mm root level, the buccolingual/palatal width was less than 5 mm, or the mesiodistal width was less than 3 mm. This was noted in female mandibular first premolars (5.6%), maxillary second premolars (4.5%), and mandibular second premolars (1.5%). Canines have adequate dimensions for OOKP surgery. However, premolars in Chinese females may be undersized in a small minority. Copyright 2017 Asia-Pacific Academy of Ophthalmology.

Treatment effects of microimplant-aided sliding mechanics on distal retraction of posterior teeth.

PubMed

Oh, Young-Hee; Park, Hyo-Sang; Kwon, Tae-Geon

2011-04-01

Our objective was to quantify the treatment effects of microimplant-aided mechanics on group distal retraction of the posterior teeth. The pretreatment and posttreatment cephalometric radiographs and dental casts of 23 patients (mean age, 22.1 ± 5.17 years), treated with distalization of the posterior teeth against microimplant anchorage and without extraction of the premolars or other teeth except the third molars, were used. The soft-tissue, skeletal, and dental measurements in the vertical and anteroposterior dimensions were analyzed. The changes in interpremolar and intermolar widths and rotations of the molars were analyzed with dental casts. The upper and lower lips were repositioned distally. The Frankfort horizontal to mandibular plane angle was decreased in the adult group. The maxillary posterior teeth were distalized by 1.4 to 2.0 mm with approximately 3.5° of distal tipping, and the mandibular posterior teeth were also distalized by 1.6 to 2.5 mm with approximately 6.6° to 8.3° of distal tipping. The maxillary posterior teeth showed intrusion by 1 mm. There were increases in arch widths at the premolars and molars. The overall success of microimplants was 89.7%; a well-experienced clinician had a higher success rate (98%) than did novices in this sample. The mean treatment time was 20 ± 4.9 months. With microimplant-aided sliding mechanics, clinicians can distalize all posterior teeth together with less distal tipping. The technique seems effective and efficient to treat patients who have mild arch length discrepancy without extractions. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Measurements using orthodontic analysis software on digital models obtained by 3D scans of plaster casts : Intrarater reliability and validity.

PubMed

Czarnota, Judith; Hey, Jeremias; Fuhrmann, Robert

2016-01-01

The purpose of this work was to determine the reliability and validity of measurements performed on digital models with a desktop scanner and analysis software in comparison with measurements performed manually on conventional plaster casts. A total of 20 pairs of plaster casts reflecting the intraoral conditions of 20 fully dentate individuals were digitized using a three-dimensional scanner (D700; 3Shape). A series of defined parameters were measured both on the resultant digital models with analysis software (Ortho Analyzer; 3Shape) and on the original plaster casts with a digital caliper (Digimatic CD-15DCX; Mitutoyo). Both measurement series were repeated twice and analyzed for intrarater reliability based on intraclass correlation coefficients (ICCs). The results from the digital models were evaluated for their validity against the casts by calculating mean-value differences and associated 95 % limits of agreement (Bland-Altman method). Statistically significant differences were identified via a paired t test. Significant differences were obtained for 16 of 24 tooth-width measurements, for 2 of 5 sites of contact-point displacement in the mandibular anterior segment, for overbite, for maxillary intermolar distance, for Little's irregularity index, and for the summation indices of maxillary and mandibular incisor width. Overall, however, both the mean differences between the results obtained on the digital models versus on the plaster casts and the dispersion ranges associated with these differences suggest that the deviations incurred by the digital measuring technique are not clinically significant. Digital models are adequately reproducible and valid to be employed for routine measurements in orthodontic practice.

Quantitative 3D analysis of bone in hip osteoarthritis using clinical computed tomography.

PubMed

Turmezei, Tom D; Treece, Graham M; Gee, Andrew H; Fotiadou, Anastasia F; Poole, Kenneth E S

2016-07-01

To assess the relationship between proximal femoral cortical bone thickness and radiological hip osteoarthritis using quantitative 3D analysis of clinical computed tomography (CT) data. Image analysis was performed on clinical CT imaging data from 203 female volunteers with a technique called cortical bone mapping (CBM). Colour thickness maps were created for each proximal femur. Statistical parametric mapping was performed to identify statistically significant differences in cortical bone thickness that corresponded with the severity of radiological hip osteoarthritis. Kellgren and Lawrence (K&L) grade, minimum joint space width (JSW) and a novel CT-based osteophyte score were also blindly assessed from the CT data. For each increase in K&L grade, cortical thickness increased by up to 25 % in distinct areas of the superolateral femoral head-neck junction and superior subchondral bone plate. For increasing severity of CT osteophytes, the increase in cortical thickness was more circumferential, involving a wider portion of the head-neck junction, with up to a 7 % increase in cortical thickness per increment in score. Results were not significant for minimum JSW. These findings indicate that quantitative 3D analysis of the proximal femur can identify changes in cortical bone thickness relevant to structural hip osteoarthritis. • CT is being increasingly used to assess bony involvement in osteoarthritis • CBM provides accurate and reliable quantitative analysis of cortical bone thickness • Cortical bone is thicker at the superior femoral head-neck with worse osteoarthritis • Regions of increased thickness co-locate with impingement and osteophyte formation • Quantitative 3D bone analysis could enable clinical disease prediction and therapy development.

Cellular and Matrix Response of the Mandibular Condylar Cartilage to Botulinum Toxin

PubMed Central

Dutra, Eliane H.; O’ Brien, Mara H.; Lima, Alexandro; Kalajzic, Zana; Tadinada, Aditya; Nanda, Ravindra; Yadav, Sumit

2016-01-01

Objectives To evaluate the cellular and matrix effects of botulinum toxin type A (Botox) on mandibular condylar cartilage (MCC) and subchondral bone. Materials and Methods Botox (0.3 unit) was injected into the right masseter of 5-week-old transgenic mice (Col10a1-RFPcherry) at day 1. Left side masseter was used as intra-animal control. The following bone labels were intraperitoneally injected: calcein at day 7, alizarin red at day 14 and calcein at day 21. In addition, EdU was injected 48 and 24 hours before sacrifice. Mice were sacrificed 30 days after Botox injection. Experimental and control side mandibles were dissected and examined by x-ray imaging and micro-CT. Subsequently, MCC along with the subchondral bone was sectioned and stained with tartrate resistant acid phosphatase (TRAP), EdU, TUNEL, alkaline phosphatase, toluidine blue and safranin O. In addition, we performed immunohistochemistry for pSMAD and VEGF. Results Bone volume fraction, tissue density and trabecular thickness were significantly decreased on the right side of the subchondral bone and mineralized cartilage (Botox was injected) when compared to the left side. There was no significant difference in the mandibular length and condylar head length; however, the condylar width was significantly decreased after Botox injection. Our histology showed decreased numbers of Col10a1 expressing cells, decreased cell proliferation and increased cell apoptosis in the subchondral bone and mandibular condylar cartilage, decreased TRAP activity and mineralization of Botox injected side cartilage and subchondral bone. Furthermore, we observed reduced proteoglycan and glycosaminoglycan distribution and decreased expression of pSMAD 1/5/8 and VEGF in the MCC of the Botox injected side in comparison to control side. Conclusion Injection of Botox in masseter muscle leads to decreased mineralization and matrix deposition, reduced chondrocyte proliferation and differentiation and increased cell apoptosis in the MCC and subchondral bone. PMID:27723812

Oral Health-Related Quality of Life Following Third Molar Surgery in an African Population

PubMed Central

Ibikunle, Adebayo Aremu; Adeyemo, Wasiu Lanre

2017-01-01

Introduction: Surgical extraction of impacted mandibular third molars is often associated with sequelae such as postoperative pain, facial edema, and limitation in mouth opening ability. These sequelae may result in changes in the patients’ lifestyle and quality of life (QoL). Aim: The aim of this study was to evaluate the effect of surgical extraction of impacted mandibular third molars on patients’ QoL in the immediate postoperative period (7 days). Materials and Methods: Ethical approval for this study was obtained from the Health Research and Ethics committee of the Lagos University Teaching Hospital. A total of 124 individuals with impacted mandibular third molars, who satisfied the inclusion criteria and consented to participate in this study, were included. The Oral Health Impact Profile-14 (OHIP-14) QoL questionnaire was used to assess QoL. QoL was assessed preoperatively (baseline) and on postoperative days (PODs) 1, 3, and 7. Maximal interincisal mouth opening, facial width, and pain were also reviewed at all evaluation points. Data analysis was done using the Statistical Package for Social Sciences (SPSS) for Windows (version 16.0, Chicago, IL, USA). Results: A total of 124 individuals were included in the final analysis. An age range of 18–51 years with a mean (±standard deviation) of 28.5 (7.4) years was observed. A male to female ratio of 1:1.5 was observed. The most frequently encountered type of impaction was the mesioangular impaction 51 (41.1%) and recurrent pericoronitis was the principal reason for extraction 53 (42.7%). The severity of the sequelae (pain, trismus, and facial edema) was maximal on the first POD. Patients’ overall QoL deteriorated sharply on the first POD and subsequently improved. Conclusion: Surgical extraction of mandibular third molars is associated with worsening of patients’ postoperative QoL in the immediate postoperative period. Prospective patients should be informed about this, and ways of reducing this untoward effect should be explored. PMID:29326504

Establishment of a new relationship between posed smile width and lower facial height: A cross-sectional study

PubMed Central

Abraham, Aby; George, Jinu; Peter, Elbe; Philip, Koshi; Chankramath, Rajesh; Johns, Dexton Antony; Bhaskar, Anitha

2015-01-01

Objective: The present study is intended to add a new parameter that would be useful in orthodontic clinical evaluation, treatment planning, and determination of vertical dimension (at occlusion). Materials and Methods: Standardized videographic recording of 79 subjects during posed smile was captured. Each video was then cut into 30 photos using the free studio software. The widest commissure-to-commissure posed smile frame (posed smile width [SW]) was selected as one of 10 or more frames showing an identical smile. Lower third of the face is measured from subnasale to soft tissue menton using a digital vernier caliper. Two values were then compared. Ratio between lower facial height and posed SW was calculated. Results: The co-relation between smiling width and lower facial height was found to be statistically significant (P < 0.01). The ratio of lower facial height and smiling width was calculated as 1.0016 with a standard deviation (SD) = 0.04 in males and 1.0301 with an SD = 0.07 in females. The difference between the mean lower facial height in males and females was statistically significant with a t = 10.231 and P = 0.000. The difference between the mean smiling width in males and females was also statistically significant with a t = 5.653 and P = 0.000. Conclusion: In class I subjects with pleasing appearance, normal facial proportions, normal overjet and overbite, and average Frankfort mandibular angle, the lower facial height (subnasale to soft tissue menton) is equal to posed SW. PMID:26430369

Influence of the cutting edge angle of a titanium instrument on chip formation in the machining of trabecular and cortical bone.

PubMed

von See, Constantin; Stoetzer, Marcus; Ruecker, Martin; Wagner, Max; Schumann, Paul; Gellrich, Nils-Claudius

2014-01-01

The placement of self-tapping implants is associated with microfractures and the formation of bone chips along the cutting flutes. This study was conducted to investigate the effect of different cutting edge angles on chip formation during the machining of trabecular and cortical bone using instruments with a rough titanium surface. Mandibular cortical and trabecular bone specimens were obtained from freshly slaughtered domestic pigs. A predefined thrust force was applied to the specimens. Four specially designed cutting instruments that simulated dental implants and had a rough titanium surface were allowed to complete one full revolution at cutting edge angles of 55, 65, 75, and 85 degrees, respectively. Torque and thrust were measured during the cutting process. Bone chips were measured and weighed under a microscope. Different cutting edge angles did not lead to significant differences in torque. The lowest torque values were measured when the cutting edges were positioned at 65 degrees in trabecular bone and at 85 degrees in cortical bone. Bone chips were significantly larger and heavier at angles of 55 and 65 degrees than at angles of 75 and 85 degrees in trabecular bone. Instruments with a rough titanium surface show considerable angle-dependent differences in chip formation. In addition to bone density, the angle of the cutting edges should be taken into consideration during the placement of dental implants. Good results were obtained when the cutting edges were positioned at an angle of 65 degrees. This angle can have positive effects on osseointegration.

Implant-Supported Fixed Partial Prostheses With Different Prosthetic Materials: A Three-Dimensional Finite Element Stress Analysis.

PubMed

Arinc, Hakan

2018-06-01

To evaluate the effects of prosthetic material on the degree of stress to the cortical bone, trabecular bone, framework, and implants using finite element analysis (FEA). A mandibular implant-supported fixed prosthesis was designed. Different prosthetic materials [cobalt-chromium-supported ceramic, zirconia-supported ceramic, and zirconia-reinforced polymethyl methacrylate (ZRPMMA)-supported resin] were used. FEA was used to evaluate stress under different loading conditions. Maximum principal (σmax), minimum principal (σmin), and von Mises (σvM) stress values were obtained. Similar σmax, σmin, and σvM values were observed in the cortical and trabecular bones and in implants under both loading conditions, with the exception of the ZRPMMA model, which showed the highest σmax, σmin, and σvM values in oblique loading. The ZRPMMA model had the lowest σvM value in the framework under both loading conditions. ZRPMMA had the lowest stress values in the framework, with increased stress values in the implants and bone tissue. Framework and veneering materials may influence stress values under different loading conditions.

IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING FEATURES OF CRANIOMANDIBULAR OSTEOPATHY IN AN AIREDALE TERRIER.

PubMed

Matiasovic, Matej; Caine, Abby; Scarpante, Elena; Cherubini, Giunio Bruto

2016-05-01

An Airedale Terrier was presented for evaluation of depression and reluctance to be touched on the head. Magnetic resonance (MR) imaging of the head was performed. The images revealed bone lesions affecting the calvarium at the level of the coronal suture and left mandibular ramus, with focal cortical destruction, expansion, and reactive new bone formation. Skull lesions were hypointense on T1-weighted sequences, hyperintense on T2-weighted sequences, and showed an intense and homogeneous enhancement after gadolinium administration. Reactive new bone formation and periosteal proliferation were confirmed histopathologically. The clinical signs, imaging findings, and histopathological examination were consistent with craniomandibular osteopathy. © 2015 American College of Veterinary Radiology.

Oral Rehabilitation of an Osteopetrosis Patient with Osteomyelitis

PubMed Central

Celakil, Tamer; Dogan, Merve; Rohlig, Bilge Gokcen; Evlioglu, Gulumser; Keskin, Haluk

2016-01-01

Osteopetrosis is a congenital disorder characterized by increasing osteoclastic function resulting in osteomyelitis in the jaws. Orofacial findings in osteopetrosis patients are unerupted, malformed, or delayed teeth and many dental caries due to vulnerable enamel and dentin and osteomyelitis. Many reports have described that maxilla is an uncommon site of occurrence for osteomyelitis due to cortical bone morphology and collateral circulation. This report aims to discuss clinical features and prosthodontic management of a patient with clinical features of adult form of osteopetrosis and osteomyelitis in both jaws. The patient has reported better masticatory and speech efficiency with removable dentures in maxillary and mandibular jaw and also self-esteem improvement and family interaction. PMID:27148461

Oral Rehabilitation of an Osteopetrosis Patient with Osteomyelitis.

PubMed

Celakil, Tamer; Dogan, Merve; Rohlig, Bilge Gokcen; Evlioglu, Gulumser; Keskin, Haluk

2016-01-01

Osteopetrosis is a congenital disorder characterized by increasing osteoclastic function resulting in osteomyelitis in the jaws. Orofacial findings in osteopetrosis patients are unerupted, malformed, or delayed teeth and many dental caries due to vulnerable enamel and dentin and osteomyelitis. Many reports have described that maxilla is an uncommon site of occurrence for osteomyelitis due to cortical bone morphology and collateral circulation. This report aims to discuss clinical features and prosthodontic management of a patient with clinical features of adult form of osteopetrosis and osteomyelitis in both jaws. The patient has reported better masticatory and speech efficiency with removable dentures in maxillary and mandibular jaw and also self-esteem improvement and family interaction.

A cooperation and competition based simple cell receptive field model and study of feed-forward linear and nonlinear contributions to orientation selectivity.

PubMed

Bhaumik, Basabi; Mathur, Mona

2003-01-01

We present a model for development of orientation selectivity in layer IV simple cells. Receptive field (RF) development in the model, is determined by diffusive cooperation and resource limited competition guided axonal growth and retraction in geniculocortical pathway. The simulated cortical RFs resemble experimental RFs. The receptive field model is incorporated in a three-layer visual pathway model consisting of retina, LGN and cortex. We have studied the effect of activity dependent synaptic scaling on orientation tuning of cortical cells. The mean value of hwhh (half width at half the height of maximum response) in simulated cortical cells is 58 degrees when we consider only the linear excitatory contribution from LGN. We observe a mean improvement of 22.8 degrees in tuning response due to the non-linear spiking mechanisms that include effects of threshold voltage and synaptic scaling factor.

Odontometric evaluation of mandibular premolars with tooth shape deviation: a case-control study.

PubMed

Chate, Robert Anthony Clive

2012-09-01

To evaluate the mean dimensions and morphologic characteristics of mandibular premolars that had mesiodistally elongated and faciolingually squeezed tooth shape deviations (MnP-TSD) and determine the population prevalence of this anomaly. Clinical photographs and study models were made for all new patients with MnP-TSD teeth who were seen over 20 years. The mesiodistal (MD) and faciolingual (FL) dimensions of the anomalous premolars were measured. MD/FL indices and MD × FL mm(2) occlusal crown areas were calculated and means and standard deviations were derived. Male and female means from the mandibular first and second anomalous premolars (MnP1/MnP2-TSD) were statistically compared against gender-specific means derived from published normative data using Student's t-tests and chi-square tests. Fifty-six individuals (33 male and 23 female) with MnP-TSD were identified, giving a male to female ratio of 1.4:1, while the prevalence rate in the indigenous British population was estimated to be 0.6%. The MD widths of the MnP1-TSD and MnP2-TSD teeth were approximately 1 mm wider than normal, while the FL diameters were about 0.5 mm and 1.5 mm narrower respectively, for the first and second premolar teeth. The MD/FL indices, instead of being under 90 as usual were above 100, while the mean MD/FL mm(2) crown surface areas were normal. This study supplies odontometric dimensional and morphologic data on MnP-TSD teeth that provide a reference source for future comparisons.

A comparative study of accuracy of linear measurements using cone beam and multi-slice computed tomographies for evaluation of mandibular canal location in dry mandibles.

PubMed

Naser, Asieh Zamani; Mehr, Bahar Behdad

2013-01-01

Cross- sectional tomograms have been used for optimal pre-operative planning of dental implant placement. The aim of the present study was to assess the accuracy of Cone Beam Computed Tomography (CBCT) measurements of specific distances around the mandibular canal by comparing them to those obtained from Multi-Slice Computed Tomography (MSCT) images. Ten hemi-mandible specimens were examined using CBCT and MSCT. Before imaging, wires were placed at 7 locations between the anterior margin of the third molar and the anterior margin of the second premolar as reference points. Following distances were measured by two observers on each cross-sectional CBCT and MSCT image: Mandibular Width (W), Length (L), Upper Distance (UD), Lower Distance (LD), Buccal Distance (BD), and Lingual Distance (LID). The obtained data were evaluated using SPSS software, applying paired t-test and intra-class correlation coefficient (ICC). There was a significant difference between the values obtained by MSCT and CBCT measurement for all areas such as H, W, UD, LD, BD, and LID, (P < 0.001), with a difference less than 1 mm. The ICC for all distances by both techniques, measured by a single observer with a one week interval and between 2 observers was 99% and 98%, respectively. Comparing the obtained data of both techniques indicates that the difference between two techniques is 2.17% relative to MSCT. The results of this study showed that there is significant difference between measurements obtained by CBCT and MSCT. However, the difference is not clinically significant.

Influence of Caloric Vestibular Stimulation on Body Experience in Healthy Humans

PubMed Central

Schönherr, Andreas; May, Christian Albrecht

2016-01-01

The vestibular system has more connections with and influence on higher cortical centers than previously thought. These interactions with higher cortical centers and the phenomena that they elicit require a structural intact cerebral cortex. To date, little is known about the role and influence of the vestibular system on one’s body experience. In this study we show that caloric vestibular stimulation (CVS) in healthy participants has an effect on the perceptive component of one’s body experience. After CVS all participants showed a statistically significant difference of thigh width estimation. In contrast to previous studies, which demonstrated an influence of CVS on higher cortical centers with an intact cerebral cortex both the cognitive and affective component of body experience were not effected by the CVS. Our results demonstrate the influence of the vestibular system on body perception and emphasize its role in modulating different perceptive-qualities which contributes to our body experience. We found that CVS has a limited influence on one’s conscious state, thought process and higher cortical functions. PMID:27013995

Condylar intramedullary intraosseous lipoma: Contribution of a new case and review of the literature

PubMed Central

Dean, Alicia; Garcia, Blas; Alamillos, Francisco; Roldan, Elisa; Blanco, Antonio

2017-01-01

Background Lipoma is the most common benign tumour of the human body, being intraosseous involvement very rare. Just 1 to 4% of all cases of lipoma are located in the oral cavity, only 0.1% being intraosseous. The jaw is its most uncommon bone location. Etiology of intraosseous lipoma (IOL) is unknown, although several theories have been proposed. Usually asymptomatic, the symptoms, when present, will depend on its location and size. Its origin may be intraosseous or juxtacortical. A biopsy is essential for diagnosis, and definitive treatment involves resection or curettage of the lesion. The aim of this paper is to present a new case of intramedullary intraosseous lipoma of the mandible with involvement of the left mandibular ramus and condylar neck. Material and Methods A case of intramedullary intraosseous lipoma (IOL) on the left mandibular ramus and condyle is presented. No history of trauma in temporomandibular joint existed. The radiology showed a radiolucent multi-lobulated lesion with values of attenuation in the range of fat. Curettage is performed and the histopathology showed a conglomerate of adipocytes without trabeculae, calcifications or atypia. Results According to the bibliography 24 cases of mandibular IOL have been described. This is the second reported case of condylar involvement and the first with cortical expansion. Conclusions Lipoma intraosseous is a very rare benign bone neoplasm. Histology is required for the differential diagnosis from other radiolucent lesions. The IOL treatment is the curettage with a good prognosis, although malignant transformation to liposarcoma has been reported in other locations. It is a disease with a difficult differential diagnosis, therefore the publication of new cases is important. Key words:Intraosseous lipoma, lipoma, jaw tumour, condylar tumour. PMID:28298998

Effect of surface treatment on stress distribution in immediately loaded dental implants--a 3D finite element analysis.

PubMed

Bahrami, Babak; Shahrbaf, Shirin; Mirzakouchaki, Behnam; Ghalichi, Farzan; Ashtiani, Mohammed; Martin, Nicolas

2014-04-01

To investigate, by means of FE analysis, the effect of surface roughness treatments on the distribution of stresses at the bone-implant interface in immediately loaded mandibular implants. An accurate, high resolution, digital replica model of bone structure (cortical and trabecular components) supporting an implant was created using CT scan data and image processing software (Mimics 13.1; Materialize, Leuven, Belgium). An anatomically accurate 3D model of a mandibular-implant complex was created using a professional 3D-CAD modeller (SolidWorks, DassaultSystèmes Solid Works Corp; 2011). Finite element models were created with one of the four roughness treatments on the implant fixture surface. Of these, three were surface treated to create a uniform coating determined by the coefficient of friction (μ); these were either (1) plasma sprayed or porous-beaded (μ=1.0), (2) sandblasted (μ=0.68) or (3) polished (μ=0.4). The fourth implant had a novel two-part surface roughness consisting of a coronal polished component (μ=0.4) interfacing with the cortical bone, and a body plasma treated surface component (μ=1) interfacing with the trabecular bone. Finite element stress analysis was carried out under vertical and lateral forces. This investigation showed that the type of surface treatment on the implant fixture affects the stress at the bone-implant interface of an immediately loaded implant complex. Von Mises stress data showed that the two-part surface treatment created the better stress distribution at the implant-bone interface. The results from this FE computational analysis suggest that the proposed two-part surface treatment for IL implants creates lower stresses than single uniform treatments at the bone-implant interface, which might decrease peri-implant bone loss. Future investigations should focus on mechanical and clinical validation of these FE results. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

The influence of sulcus width on simulated electric fields induced by transcranial magnetic stimulation

PubMed Central

Janssen, A M; Rampersad, S M; Lucka, F; Lanfer, B; Lew, S; Aydin, Ü; Wolters, C H; Stegeman, D F; Oostendorp, T F

2013-01-01

Volume conduction models can help in acquiring knowledge about the distribution of the electric field induced by transcranial magnetic stimulation (TMS). One aspect of a detailed model is an accurate description of the cortical surface geometry. Since its estimation is difficult, it is important to know how accurate the geometry has to be represented. Previous studies only looked at the differences caused by neglecting the complete boundary between the CSF and GM (Thielscher et al. 2011; Bijsterbosch et al. 2012), or by resizing the whole brain (Wagner et al. 2008). However, due to the high conductive properties of the CSF, it can be expected that alterations in sulcus width can already have a significant effect on the distribution of the electric field. To answer this question, the sulcus width of a highly realistic head model, based on T1-, T2- and diffusion-weighted magnetic resonance images (MRI), was altered systematically. This study shows that alterations in the sulcus width do not cause large differences in the majority of the electric field values. However, considerable overestimation of sulcus width produces an overestimation of the calculated field strength, also at locations distant from the target location. PMID:23787706

Biomechanical behavior of 2-implant-and single-implant-retained mandibular overdentures with conventional or mini implants.

PubMed

Pisani, Marina Xavier; Presotto, Anna Gabriella Camacho; Mesquita, Marcelo Ferraz; Barão, Valentim Adelino Ricardo; Kemmoku, Daniel Takanori; Del Bel Cury, Altair Antoninha

2018-04-24

The use of single or mini dental implants to retain mandibular overdentures is still questionable. The purpose of this finite element analysis (FEA) study was to investigate the biomechanical behavior of 2- and single-implant-retained mandibular overdentures with conventional or mini implants. Four 3-dimensional (3D) finite element models were constructed with the following designs of mandibular overdentures: 2 (group 2-C) and single (group 1-C) conventional external hexagon implants with ball or O-ring attachment and 2 (group 2-M) and single (group 1-M) 1-piece mini implants. A 150-N axial load was applied bilaterally and simultaneously on the first molar. Overdenture displacement, von Mises equivalent stress (implants and/or prosthetic components), and maximum principal stresses (peri-implant bone) were recorded numerically and then color-coded and compared among the groups. The overdenture displacement (in mm) was higher for the 1-M (0.16) and 2-M (0.17) groups when compared with 1-C (0.09) and 2-C (0.08). Irrespective of the type of implant, the single-implant groups presented higher values of stress (in MPa) on the implants than did the 2-implant groups (1-C=52.53; 1-M=2.95; 2-C=34.66; 2-M=2.37), ball attachment (1-C=201.33; 2-C=159.06), housing or O-ring (1-C=125.01; 1-M=1.96; 2-C=88.84; 2-M=1.27), and peri-implant cortical bone (1-C=19.37; 1-M=1.47; 2-C=15.70; 2-M=1.06). The mini implant overdentures presented lower stress values on the implants, housing or O-ring, and peri-implant bone than did the conventional implant overdentures, regardless of the number of implants. The 2-implant-retained overdentures exhibited lower stresses than the single- implant-retained overdentures, irrespective of the type of implant. The mini implants demonstrated higher overdenture displacement and lower stresses than did conventional implant overdentures for single- and 2-implant-retained overdentures. Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Accuracy of four different digital intraoral scanners: effects of the presence of orthodontic brackets and wire.

PubMed

Jung, Yoo-Ran; Park, Ji-Man; Chun, Youn-Sic; Lee, Kkot-Nim; Kim, Minji

The objective of this study was to compare the accuracy of four different digital intraoral scanners and the effects of buccal brackets and orthodontic wire. For this study, three sets of models (Control model, BKT model with buccal bracket, and WBKT model with buccal bracket and orthodontic wire) were scanned using four different types of intraoral scanners: E4D dentist, iTero, Trios, and Zfx IntraScan. The mesiodistal width of the teeth, intercanine width, and intermolar width measured by four scanners were compared. Three-dimensional (3D) images of the brackets were taken using the four scanners. Data were analyzed with one-way ANOVA, independent t test, and post-hoc Tukey test at a significance level of P < 0.05. When comparing the 3D images with manual measurements using a traditional caliper, iTero and Trios showed the highest accuracy in horizontal measurements.iTero had the lowest values in Devmax-min of maxillary intermolar and intercanine widths (0.16 mm and 0.20 mm, respectively), whereas Trios had the lowest values in Devmax-min of mandibular intermolar and intercanine widths (0.36 mm and 0.14 mm, respectively). The horizontal variables were barely affected by the presence of buccal brackets and orthodontic wire. Comparison of 3D bracket images scanned by the four scanners showed differences in image distortion among the scanners. Bracket characteristics did not affect the 3D bracket images. The four intraoral scanners used in this study differed in accuracy. However, the results acquired by iTero and Trios were more reliable. Effects of buccal brackets and orthodontic wire on the 3D images taken by intraoral scanners were not clinically significant.

Influence of Number of Implants and Attachment Type on Stress Distribution in Mandibular Implant-Retained Overdentures: Finite Element Analysis

PubMed Central

El-Anwar, Mohamed I.; El-Taftazany, Eman A.; Hamed, Hamdy A.; ElHay, Mohamed A. Abd

2017-01-01

AIM: This study aimed to compare the stresses generated by using two or four root form dental implants supporting mandibular overdentures that were retained with ball and locator attachments. METHODS: Under ANSYS environment, four 3D finite element models were prepared. These models simulated complete overdentures supported by two or four implants with either ball or locator attachments as a connection mechanism. The models’ components were created by CAD/CAM package then were imported to ANSYS. Load of 100 N was applied at the right premolar/molar region vertically and at an oblique angle of 110° from lingual direction. RESULTS: Within the conditions of this research, in all cases, it was found that cortical and cancellous bone regions were the least to be stressed. Also, the ball attachment produced higher stresses. CONCLUSION: Caps deformation and stresses are negligible in cases of using locator attachment in comparison to ball attachments. This may indicate longer lifetime and less repair/maintenance operations in implant overdentures retained by locator attachments. Although the study revealed that bone was insensitive to a number of implants or attachment type, it may be recommended to use two implants in the canine region than using four, where the locator attachments were found to be better. PMID:28507636

Influence of Number of Implants and Attachment Type on Stress Distribution in Mandibular Implant-Retained Overdentures: Finite Element Analysis.

PubMed

El-Anwar, Mohamed I; El-Taftazany, Eman A; Hamed, Hamdy A; ElHay, Mohamed A Abd

2017-04-15

This study aimed to compare the stresses generated by using two or four root form dental implants supporting mandibular overdentures that were retained with ball and locator attachments. Under ANSYS environment, four 3D finite element models were prepared. These models simulated complete overdentures supported by two or four implants with either ball or locator attachments as a connection mechanism. The models' components were created by CAD/CAM package then were imported to ANSYS. Load of 100 N was applied at the right premolar/molar region vertically and at an oblique angle of 110° from lingual direction. Within the conditions of this research, in all cases, it was found that cortical and cancellous bone regions were the least to be stressed. Also, the ball attachment produced higher stresses. Caps deformation and stresses are negligible in cases of using locator attachment in comparison to ball attachments. This may indicate longer lifetime and less repair/maintenance operations in implant overdentures retained by locator attachments. Although the study revealed that bone was insensitive to a number of implants or attachment type, it may be recommended to use two implants in the canine region than using four, where the locator attachments were found to be better.

Clinical significance of computed tomography assessment for third molar surgery

PubMed Central

Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

2014-01-01

Surgical extraction of the third molar is the most commonly performed surgical procedure in the clinical practice of oral surgery. Third molar surgery is warranted when there is inadequate space for eruption, malpositioning, or risk for cyst or odontogenic tumor formation. Preoperative assessment should include a detailed morphologic analysis of the third molar and its relationship to adjacent structures and surrounding tissues. Due to developments in medical engineering technology, computed tomography (CT) now plays a critical role in providing the clear images required for adequate assessment prior to third molar surgery. Removal of the maxillary third molar is associated with a risk for maxillary sinus perforation, whereas removal of the mandibular third molar can put patients at risk for a neurosensory deficit from damage to the lingual nerve or inferior alveolar nerve. Multiple factors, including demographic, anatomic, and treatment-related factors, influence the incidence of nerve injury during or following removal of the third molar. CT assessment of the third molar prior to surgery can identify some of these risk factors, such as the absence of cortication between the mandibular third molar and the inferior alveolar canal, prior to surgery to reduce the risk for nerve damage. This topic highlight presents an overview of the clinical significance of CT assessment in third molar surgery. PMID:25071882

Cortical integrity of the inferior alveolar canal as a predictor of paresthesia after third-molar extraction.

PubMed

Park, Wonse; Choi, Ji-Wook; Kim, Jae-Young; Kim, Bong-Chul; Kim, Hyung Jun; Lee, Sang-Hwy

2010-03-01

Paresthesia is a well-known complication of extraction of mandibular third molars (MTMs). The authors evaluated the relationship between paresthesia after MTM extraction and the cortical integrity of the inferior alveolar canal (IAC) by using computed tomography (CT). The authors designed a retrospective cohort study involving participants considered, on the basis of panoramic imaging, to be at high risk of experiencing injury of the inferior alveolar nerve who subsequently underwent CT imaging and extraction of the MTMs. The primary predictor variable was the contact relationship between the IAC and the MTM as viewed on a CT image, classified into three groups: group 1, no contact; group 2, contact between the MTM and the intact IAC cortex; group 3, contact between the MTM and the interrupted IAC cortex. The secondary predictor variable was the number of CT image slices showing the cortical interruption around the MTM. The outcome variable was the presence or absence of postoperative paresthesia after MTM extraction. The study sample comprised 179 participants who underwent MTM extraction (a total of 259 MTMs). Their mean age was 23.6 years, and 85 (47.5 percent) were male. The overall prevalence of paresthesia was 4.2 percent (11 of 259 teeth). The prevalence of paresthesia in group 3 (involving an interrupted IAC cortex) was 11.8 percent (10 of 85 cases), while for group 2 (involving an intact IAC cortex) and group 1 (involving no contact) it was 1.0 percent (1 of 98 cases) and 0.0 percent (no cases), respectively. The frequency of nerve damage increased with the number of CT image slices showing loss of cortical integrity (P=.043). The results of this study indicate that loss of IAC cortical integrity is associated with an increased risk of experiencing paresthesia after MTM extraction.

A comparison of bone density and bone morphology between patients presenting with hip fractures, spinal fractures or a combination of the two

PubMed Central

2013-01-01

Background Currently it is uncertain how to define osteoporosis and who to treat after a hip fracture. There is little to support the universal treatment of all such patients but how to select those most in need of treatment is not clear. In this study we have compared cortical and trabecular bone status between patients with spinal fractures and those with hip fracture with or without spinal fracture with the aim to begin to identify, by a simple clinical method (spine x-ray), a group of hip fracture patients likely to be more responsive to treatment with current antiresorptive agents. Methods Comparison of convenience samples of three groups of 50 patients, one with spinal fractures, one with a hip fracture, and one with both. Measurements consist of bone mineral density at the lumbar spine, at the four standard hip sites, number, distribution and severity of spinal fractures by the method of Genant, cortical bone thickness at the infero-medial femoral neck site, femoral neck and axis length and femoral neck width. Results Patients with spinal fractures alone have the most deficient bones at both trabecular and cortical sites: those with hip fracture and no spinal fractures the best at trabecular bone and most cortical bone sites: and those with both hip and spinal fractures intermediate in most measurements. Hip axis length and neck width did not differ between groups. Conclusion The presence of the spinal fracture indicates poor trabecular bone status in hip fracture patients. Hip fracture patients without spinal fractures have a bone mass similar to the reference range for their age and gender. Poor trabecular bone in hip fracture patients may point to a category of patient more likely to benefit from therapy and may be indicated by the presence of spinal fractures. PMID:23432767

Sexual dimorphism of sulcal morphology of the ferret cerebrum revealed by MRI-based sulcal surface morphometry

PubMed Central

Sawada, Kazuhiko; Horiuchi-Hirose, Miwa; Saito, Shigeyoshi; Aoki, Ichio

2015-01-01

The present study quantitatively assessed sexual dimorphism of cortical convolution and sulcal morphology in young adult ferrets by MRI-based sulcal surface morphometry. Ex vivo T1-weighted (short TR/TE) MRI of the ferret cerebrum was acquired with high spatial resolution at 7-tesla. The degree of cortical convolution, evaluated quantitatively based on 3D MRI data by sulcation index (SI), was significantly greater in males (0.553 ± 0.036) than in females (0.502 ± 0.043) (p < 0.001). The rostrocaudal distribution of the cortical convolution revealed a greater convolution in the frontal region of the cortex in males than in females and by a posterior extension of the convolution in the temporo-parieto-occipital region of males. Although the cerebral width in the frontal region was not different between sexes, the rhinal fissure and rostral region of splenial sulcus were more infolded in males than in females. On the contrary, the cerebral width was greater in males in the temporo-parieto-occipital region, and male-prominent posterior extension of infolding was noted in the lateral sulcus, caudal suprasylvian sulcus, pesudosylvian sulcus, hippocampal sulcus, and the caudal region of splenial sulcus. Notably, the caudal descending region of lateral sulcus was clearly infolded in males, but obscured in females. The present results suggest a region-related sexual dimorphism of the sulcal infolding, which is reflected by local cortical expansion in the ferret cerebrum. In particular, male-favored sulcal infolding with expansion of the temporo-parieto-occipital neocortex may be relevant to the human cerebral cortex regarding visuo-spatial and emotion processing, which are known to differ between sexes. The present results will provide fundamental information assessing sex-related changes in the regional sulcal infolding, when ferrets with experimentally-induced gyrification abnormality will be used as models for male-prevalent or male-earlier-onset neurodevelopmental disorders. PMID:25999821

A 14-day ground-based hypokinesia study in nonhuman primates: A compilation of results

NASA Technical Reports Server (NTRS)

Kazarian, L.; Cann, C. E.; Parfitt, M.; Simmons, D.; Morey-Holton, E.

1981-01-01

A 14 day ground based hypokinesia study with rhesus monkeys was conducted to determine if a spaceflight of similar duration might affect bone remodeling and calcium homeostatis. The monkeys were placed in total body casts and sacrificed either immediately upon decasting or 14 days after decasting. Changes in vertebral strength were noted and further deterioration of bone strength continued during the recovery phase. Resorption in the vertebrae increased dramatically while formation decreased. Cortical bone formation was impaired in the long bones. The immobilized animals showed a progressive decrease in total serum calcium which rebounded upon remobilization. Most mandibular parameters remained unchanged during casting except for retardation of osteon birth or maturation rate and density distribution of matrix and mineral moieties.

Increase of cortical bone after a cementless long stem in periprosthetic fractures.

PubMed

García-Rey, Eduardo; García-Cimbrelo, Eduardo; Cruz-Pardos, Ana; Madero, Rosário

2013-12-01

Healing and functional recovery have been reported using an extensively porous-coated stem in Vancouver B2 and B3 periprosthetic fractures; however, loss of cortical bone has been observed when using these stems in revision surgery for aseptic loosening. However, it is unclear whether this bone loss influences subsequent loosening. We analyze the healing fracture rate and whether the radiographic changes observed around and extensively porous-coated stem used for periprosthetic fractures affect function or loosening. We retrospectively reviewed 35 patients with periprosthetic fractures (20 Vancouver B2 and 15 Vancouver B3). Patients' mean age at surgery was 80 years (range, 51-86 years). No cortical struts were used in this series. We evaluated radiographs for signs of loosening or subsidence. The cortical index and the femoral cortical width were measured at different levels on the immediate pre- and postoperative radiographs and at different periods of followup. The minimum followup was 3 years (mean, 8.3 years; range, 3-17 years). All fractures had healed, and all stems were clinically and radiographically stable at the end of followup. Nineteen hips showed nonprogressive radiographic subsidence during the first 3 postoperative months without clinical consequences. The cortical index and the lateral and medial cortical thickness increased over time. Increase of femoral cortex thicknesses was greater in cases with moderate preoperative osteoporosis and in cases with stems less than 16 mm in thickness. Our data suggest an extensively porous-coated stem for Vancouver B2 and B3 periprosthetic fractures leads to a high rate of union and stable fixation. Cortical index and lateral cortex thickness increased in these patients with periprosthetic fractures. Patients with moderate osteoporosis and those using thin stems showed a major increase in femoral cortex thickness over time.

Short-duration exercise and confinement alters bone mineral content and shape in weanling horses.

PubMed

Hiney, K M; Nielsen, B D; Rosenstein, D

2004-08-01

The hypothesis that short-duration exercise may ameliorate the decrease in bone mass observed with confinement was investigated with 18 quarter horses (nine colts and nine fillies) weaned at 4 mo of age and placed into box stalls. After a 5-wk adjustment period, individuals were grouped by age and weight, and then divided randomly into three treatment groups: 1) group housed; 2) confined with no exercise; and 3) confined with exercise. The confined and exercised groups were housed in 3.7 m x 3.7 m box stalls for the 56-d duration of the trial. The exercised group was sprinted 82 m/d, 5 d/wk, in a fenced grass alleyway. The weanlings were led down an alleyway, turned loose in a small pen, and then released and allowed to run back down the alley. The group horses were housed together in a 992-m2 drylot with free access to exercise. On d 0, 28, and 56, dorsopalmar and lateromedial radiographs of the left third metacarpal bone were taken to estimate changes in bone mineral content and cortical widths. Mean values of medial, lateral, and total radiographic bone aluminum equivalence increased over time (P < 0.05), whereas dorsal and palmar radiographic bone aluminum equivalence did not change significantly. Dorsal, medial, and total radiographic bone aluminum equivalence tended (P = 0.09) to differ by a treatment x day interaction, with values increasing over time only in the exercised group. Normalized medial and total radiographic bone aluminum equivalence tended (P < 0.1) to differ (P < 0.01) with treatment, with exercised horses having greater bone aluminum equivalence than confined horses. Dorsopalmar cortical width in exercised horses was greater than on d 56 (treatment x day; P = 0.07). The dorsopalmar medullary cavity decreased in exercised vs. group-housed horses (P = 0.027), whereas dorsal and medial cortical width tended to increase only in the exercised horses (treatment x day; P < 0.01). This study indicated that a short-duration exercise protocol might be effective in improving bone mass and therefore skeletal strength in horses.

Using stereotactic brain atlases for small rodents and nonhuman primates for optrode array customization

NASA Astrophysics Data System (ADS)

Boutte, Ronald W.; Merlin, Sam; Griffiths, Brandon; Parry, Trent; Blair, Steve

2017-02-01

As the optogenetic field expands its need to target with high specificity only grows more crucial. This work will show a method for customizing soda-lime glass optrode arrays so that fine structures within the brains of small rodents and nonhuman primates can be optically interrogated below the outer cortical layer. An 8 × 6 array is customized for optrode length (400 μm ), optrode width (75 μm ), optrode pitch (400 μm ), backplane thickness (500 μm ), and overall form factor (3.45 mm × 2.65 mm ). The 400 μm long optrode is capable of illuminating the cortical Layer IV of rhesus macaque ( Macaca Fascicularis ) and the motor cortex of small mice ( Mus Musculus ).

One-stage closure of isolated cleft palate with the Veau-Wardill-Kilner V to Y pushback procedure or the Cronin modification. II. Height, weight and comparison of dental arches.

PubMed

Heliövaara, A; Pere, A; Ranta, R

1994-03-01

The body height and weight, and sizes of dental arches in 116 patients with isolated cleft palate were evaluated at 16.9-20.6 years of age. One-stage closure of the soft and hard palate had been done at a mean age of 1.8 years using the Veau-Wardill-Kilner or the Cronin mucoperiosteal palatal V-Y pushback technique. The height attained in both the boys (177.6 cm) and the girls (165.7 cm) was similar to that in the general adult population, even though half of the boys had not reached their final height. The median relative weight for height and sex was 6%. There were no significant differences in dental arch measurements depending on the method of operation but the more palatal operations done the shorter the maxillary and mandibular dental arch widths. The extent of cleft made a significant difference, larger clefts having narrower palatal intercanine widths. Dental arch dimensions were consistently larger in boys than in girls.

Mathematical beta function formulation for maxillary arch form prediction in normal occlusion population.

PubMed

Mina, Morteza; Borzabadi-Farahani, Ali; Tehranchi, Azita; Nouri, Mahtab; Younessian, Farnaz

2017-04-01

The aim of this study was to assess the dental arch curvature in subjects with normal occlusion in an Iranian population and propose a beta function formula to predict maxillary arch form using the mandibular intermolar widths (IMW) and intermolar depths (IMD). The materials used were study casts of 54 adolescents with normal occlusion and mean age of 14.1 years (25 males, 29 females, age range 12-16 years). Curve-fitting analyses were carried out and the curves passing through the facial-axis point of the canines, premolars, first molars, and the incisal edges of the anterior teeth were studied using a 3D laser scanner. Using the measured IMW and IMD of the dental arches at the maxillary and mandibular first molar region, a beta function formula proposed for predicting maxillary arch form. The accuracy of the proposed formula was assessed on 10 randomly selected dental casts. The mean (SD) of the maxillary and mandibular IMW and IMD were 57.92 (4.75), 54.19 (5.31), and 31.59 (2.90) and 28.10 (2.59) mm, respectively. There was no gender dimorphism (P > 0.05) for both variables (IMW, IMD). There was a strong positive association (n = 10, Pearson r = 0.98, P < 0.05) between the measured (actual) maxillary arch length and proposed arch length derived from generated formula. The goodness of fit (whole arch) for the proposed beta function formula, using adjusted r square measure and root mean square in 10 patients averaged 0.97 and 1.49 mm, respectively. The corresponding figures for the maxillary anterior arch (canine to canine) were 0.90 and 0.92 mm, respectively. The proposed beta function formula used for predicting maxillary arch form based on two mandibular measures (IMW, IMD) was found to have a high accuracy for maxillary arch prediction in the Iranian population and may be used as a guide to fabricate customized arch wires or as an aid in maxillary reconstructive surgery.

The influence of sulcus width on simulated electric fields induced by transcranial magnetic stimulation

NASA Astrophysics Data System (ADS)

Janssen, A. M.; Rampersad, S. M.; Lucka, F.; Lanfer, B.; Lew, S.; Aydin, Ü.; Wolters, C. H.; Stegeman, D. F.; Oostendorp, T. F.

2013-07-01

Volume conduction models can help in acquiring knowledge about the distribution of the electric field induced by transcranial magnetic stimulation. One aspect of a detailed model is an accurate description of the cortical surface geometry. Since its estimation is difficult, it is important to know how accurate the geometry has to be represented. Previous studies only looked at the differences caused by neglecting the complete boundary between cerebrospinal fluid (CSF) and grey matter (Thielscher et al 2011 NeuroImage 54 234-43, Bijsterbosch et al 2012 Med. Biol. Eng. Comput. 50 671-81), or by resizing the whole brain (Wagner et al 2008 Exp. Brain Res. 186 539-50). However, due to the high conductive properties of the CSF, it can be expected that alterations in sulcus width can already have a significant effect on the distribution of the electric field. To answer this question, the sulcus width of a highly realistic head model, based on T1-, T2- and diffusion-weighted magnetic resonance images, was altered systematically. This study shows that alterations in the sulcus width do not cause large differences in the majority of the electric field values. However, considerable overestimation of sulcus width produces an overestimation of the calculated field strength, also at locations distant from the target location.

Maxillary Expansion and Mandibular Setback Surgery With and Without Mandibular Anterior Segment Osteotomy to Correct Mandibular Prognathism With Obstructive Sleep Apnea.

PubMed

Han, Jeong Joon; Hong, Dong Hwan; Hwang, Soon Jung

2017-05-01

Mandibular prognathism is usually treated with mandibular setback surgery. However, this approach reduces the pharyngeal airway space, and can aggravate obstructive phenomena in patients with obstructive sleep apnea (OSA). While maxillary expansion is known to lead to an increase in the pharyngeal airway volume (PAS), its effect on the PAS in mandibular setback surgery has not yet been reported. The authors report a surgical approach with maxillary expansion in 2 patients with mandibular prognathism that was accompanied by OSA: maxillary midsagittal expansion with minimum maxillary advancement and minor mandibular setback without mandibular anterior segmental osteotomy (ASO) or major mandibular setback with mandibular ASO. Preoperative and postoperative computed tomography and polysomnography indicated that OSA was improved and pharyngeal airway space was increased or sustained, and the prognathic profile could be corrected to an acceptable facial esthetic profile. In summary, maxillary transversal expansion and mandibular setback with or without mandibular ASO can be successfully applied to treat mandibular prognathism with OSA.

Cephalometric skeletal evaluation of patients with Incontinentia Pigmenti

PubMed Central

Maahs, Marcia Angelica Peter; Kiszewski, Ana Elisa; Rosa, Rafael Fabiano Machado; Maria, Fernanda Diffini Santa; Prates, Frederico Ballvé; Zen, Paulo Ricardo Gazzola

2014-01-01

Purpose The aim of this study was to evaluate the skeletal characteristics of patients with the rare genetic disease of Incontinentia Pigmenti, by lateral cephalometric analysis on the antero-posterior plane and by frontal cephalometric analysis on the horizontal plane. Methods Lateral skeletal cephalometric analyses were performed according to Steiner for evaluation of antero-posterior direction, and frontal skeletal cephalometric analyses according to Ricketts for evaluation of horizontal direction in 9 patients with IP. Left and right facial widths at the level of the zygomatic arch were also evaluated. The Student t-test was used for paired to a 5% level of significance data. Results The lateral skeletal cephalometric findings were not statistically significant, but the Class II was the most frequent finding (44.4%), followed by Class III (33.3%) and Class I (22.2%). The right maxillo-mandibular width was significantly lower than normal values, and the right facial width was significantly higher than the left, at the level of the zygomatic arch. Conclusions Patients with IP showed more skeletal discrepancies of Class II and III than Class I malocclusion, and had significant horizontal facial skeletal asymmetries. This should alert health professionals to route these patients for orthodontic assessment and possible therapeutic interventions. However, larger samples are needed to better elucidate if these cephalometric findings can be specifically related to IP. PMID:25737924

Influence of sex and ethnic tooth-size differences on mixed-dentition space analysis

PubMed Central

Altherr, Edward R.; Koroluk, Lorne D.; Phillips, Ceib

2013-01-01

Introduction Most mixed-dentition space analyses were developed by using subjects of northwestern European descent and unspecified sex. The purpose of this study was to determine the predictive accuracy of the Tanaka-Johnston analysis in white and black subjects in North Carolina. Methods A total of 120 subjects (30 males and 30 females in each ethnic group) were recruited from clinics at the University of North Carolina School of Dentistry. Ethnicity was verified to 2 previous generations. All subjects were less than 21 years of age and had a full complement of permanent teeth. Digital calipers were used to measure the mesiodistal widths of all teeth on study models fabricated from alginate impressions. The predicted widths of the canines and the premolars in both arches were compared with the actual measured widths. Results In the maxillary arch, there was a significant interaction of ethnicity and sex on the predictive accuracy of the Tanaka-Johnston analysis (P = .03, factorial ANOVA). The predictive accuracy was significantly overestimated in the white female group (P <.001, least square means). In the mandibular arch, there was no significant interaction between ethnicity and sex (P = .49). Conclusions The Tanaka-Johnston analysis significantly overestimated in females (P <.0001) and underestimated in blacks (P <.0001) (factorial ANOVA). Regression equations were developed to increase the predictive accuracy in both arches. (Am J Orthod Dentofacial Orthop 2007;132:332-9) PMID:17826601

Analysis and evaluation of relative positions of mandibular third molar and mandibular canal impacts

PubMed Central

Kim, Hang-Gul

2014-01-01

Objectives This study used cone-beam computed tomography (CBCT) images to categorize the relationships between the mandibular canal and the roots and investigated the prevalence of nerve damage. Materials and Methods Through CBCT images, contact and three-dimensional positional relationships between the roots of the mandibular third molar and the mandibular canal were investigated. With this data, prevalence of nerve damage according to the presence of contact and three-dimensional positional relationships was studied. Other factors that affected the prevalence of nerve damage were also investigated. Results When the mandibular third molar and the mandibular canal were shown to have direct contact in CBCT images, the prevalence of nerve damage was higher than in other cases. Also, in cases where the mandibular canal was horizontally lingual to the mandibular third molar and the mandibular canal was vertically at the cervical level of the mandibular third molar, the prevalence of nerve damage was higher than in opposite cases. The percentage of mandibular canal contact with the roots of the mandibular third molar was higher when the mandibular canal was horizontally lingual to the mandibular third molar. Finally, the prevalence of nerve damage was higher when the diameter of the mandibular canal lumen suddenly decreased at the contact area between the mandibular canal and the roots, as shown in CBCT images. Conclusion The three-dimensional relationship of the mandibular third molar and the mandibular canal can help predict nerve damage and can guide patient expectations of the possibility and extent of nerve damage. PMID:25551092

Panoramic radiographic predictors of mandibular third molar eruption.

PubMed

Niedzielska, Iwona Anna; Drugacz, Jan; Kus, Nina; Kreska, Joanna

2006-08-01

Third molar (M3) eruption can be problematic. According to some orthodontic surgeons, the teeth are capable of aggravating the average crowding level in the dental arch. The question is whether it might be possible to give a prognosis for ultimate M3 position in the arch and make an early decision to extract or retain them. The purpose of the study was to determine which measurements made on panoramic tomograms might facilitate prognosis for M3 position in the dental arch over the years. The investigation involved 64 patients who had been enrolled to the study group 10 years earlier, ie, in 1993, when an analysis had been carried out regarding M3 effect on dental arch crowding. At that time panoramic tomograms had been taken, and dental casts made. The procedures were repeated in 2003. The following measurements were taken at baseline (1993) and at the end of the study (2003): (1)/the retromolar space to lower third molar crown width, (2) third molar angulation to the base of the mandible, and (3) third molar to second molar inclination. At some defined values of the Ganss ratio, and M3 inclination to mandibular base and second molar, it is possible to predict potential lower third molar alignment in the dental arch using a panoramic radiograph.

A gradient in cortical pathology in multiple sclerosis by in vivo quantitative 7 T imaging

PubMed Central

Louapre, Céline; Govindarajan, Sindhuja T.; Giannì, Costanza; Nielsen, A. Scott; Cohen-Adad, Julien; Sloane, Jacob; Kinkel, Revere P.

2015-01-01

We used a surface-based analysis of T2* relaxation rates at 7 T magnetic resonance imaging, which allows sampling quantitative T2* throughout the cortical width, to map in vivo the spatial distribution of intracortical pathology in multiple sclerosis. Ultra-high resolution quantitative T2* maps were obtained in 10 subjects with clinically isolated syndrome/early multiple sclerosis (≤3 years disease duration), 18 subjects with relapsing-remitting multiple sclerosis (≥4 years disease duration), 13 subjects with secondary progressive multiple sclerosis, and in 17 age-matched healthy controls. Quantitative T2* maps were registered to anatomical cortical surfaces for sampling T2* at 25%, 50% and 75% depth from the pial surface. Differences in laminar quantitative T2* between each patient group and controls were assessed using general linear model (P < 0.05 corrected for multiple comparisons). In all 41 multiple sclerosis cases, we tested for associations between laminar quantitative T2*, neurological disability, Multiple Sclerosis Severity Score, cortical thickness, and white matter lesions. In patients, we measured, T2* in intracortical lesions and in the intracortical portion of leukocortical lesions visually detected on 7 T scans. Cortical lesional T2* was compared with patients’ normal-appearing cortical grey matter T2* (paired t-test) and with mean cortical T2* in controls (linear regression using age as nuisance factor). Subjects with multiple sclerosis exhibited relative to controls, independent from cortical thickness, significantly increased T2*, consistent with cortical myelin and iron loss. In early disease, T2* changes were focal and mainly confined at 25% depth, and in cortical sulci. In later disease stages T2* changes involved deeper cortical laminae, multiple cortical areas and gyri. In patients, T2* in intracortical and leukocortical lesions was increased compared with normal-appearing cortical grey matter (P < 10−10 and P < 10−7), and mean cortical T2* in controls (P < 10−5 and P < 10−6). In secondary progressive multiple sclerosis, T2* in normal-appearing cortical grey matter was significantly increased relative to controls (P < 0.001). Laminar T2* changes may, thus, result from cortical pathology within and outside focal cortical lesions. Neurological disability and Multiple Sclerosis Severity Score correlated each with the degree of laminar quantitative T2* changes, independently from white matter lesions, the greatest association being at 25% depth, while they did not correlate with cortical thickness and volume. These findings demonstrate a gradient in the expression of cortical pathology throughout stages of multiple sclerosis, which was associated with worse disability and provides in vivo evidence for the existence of a cortical pathological process driven from the pial surface. PMID:25681411

[Ewing sarcoma located in the mandible: A case report].

PubMed

Hernandez, M; Droz, D; Mansuy, L; Simon, E; Chastagner, P

2015-06-01

Ewing sarcoma is the second most common primary malignant bone cancer in children and adolescents. Clinical presentation is usually dominated by local pain and a palpable mass. These symptoms justify imaging investigations: the first one, when an osseous lesion is suspected, is usually a conventional radiograph in two planes. Ewing sarcoma appears as a poorly defined osteolytic lesion that may frequently be associated with cortical erosion or laminar periosteal response ("onion skin"). However, this aspect is not pathognomonic and the definitive diagnosis is made by biopsy. Absence of pain or an unusual localization can lead to misdiagnosis. We report the case of a 7-year-old boy with Ewing sarcoma located in the mandible with a clinical picture including progressive mandibular swelling but no pain. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Finite Element Simulation and Additive Manufacturing of Stiffness-Matched NiTi Fixation Hardware for Mandibular Reconstruction Surgery

PubMed Central

Jahadakbar, Ahmadreza; Shayesteh Moghaddam, Narges; Amerinatanzi, Amirhesam; Dean, David; Karaca, Haluk E.; Elahinia, Mohammad

2016-01-01

Process parameters and post-processing heat treatment techniques have been developed to produce both shape memory and superelastic NiTi using Additive Manufacturing. By introducing engineered porosity, the stiffness of NiTi can be tuned to the level closely matching cortical bone. Using additively manufactured porous superelastic NiTi, we have proposed the use of patient-specific, stiffness-matched fixation hardware, for mandible skeletal reconstructive surgery. Currently, Ti-6Al-4V is the most commonly used material for skeletal fixation devices. Although this material offers more than sufficient strength for immobilization during the bone healing process, the high stiffness of Ti-6Al-4V implants can cause stress shielding. In this paper, we present a study of mandibular reconstruction that uses a dry cadaver mandible to validate our geometric and biomechanical design and fabrication (i.e., 3D printing) of NiTi skeletal fixation hardware. Based on the reference-dried mandible, we have developed a Finite Element model to evaluate the performance of the proposed fixation. Our results show a closer-to-normal stress distribution and an enhanced contact pressure at the bone graft interface than would be in the case with Ti-6Al-4V off-the-shelf fixation hardware. The porous fixation plates used in this study were fabricated by selective laser melting. PMID:28952598

Finite Element Simulation and Additive Manufacturing of Stiffness-Matched NiTi Fixation Hardware for Mandibular Reconstruction Surgery.

PubMed

Jahadakbar, Ahmadreza; Shayesteh Moghaddam, Narges; Amerinatanzi, Amirhesam; Dean, David; Karaca, Haluk E; Elahinia, Mohammad

2016-12-19

Process parameters and post-processing heat treatment techniques have been developed to produce both shape memory and superelastic NiTi using Additive Manufacturing. By introducing engineered porosity, the stiffness of NiTi can be tuned to the level closely matching cortical bone. Using additively manufactured porous superelastic NiTi, we have proposed the use of patient-specific, stiffness-matched fixation hardware, for mandible skeletal reconstructive surgery. Currently, Ti-6Al-4V is the most commonly used material for skeletal fixation devices. Although this material offers more than sufficient strength for immobilization during the bone healing process, the high stiffness of Ti-6Al-4V implants can cause stress shielding. In this paper, we present a study of mandibular reconstruction that uses a dry cadaver mandible to validate our geometric and biomechanical design and fabrication (i.e., 3D printing) of NiTi skeletal fixation hardware. Based on the reference-dried mandible, we have developed a Finite Element model to evaluate the performance of the proposed fixation. Our results show a closer-to-normal stress distribution and an enhanced contact pressure at the bone graft interface than would be in the case with Ti-6Al-4V off-the-shelf fixation hardware. The porous fixation plates used in this study were fabricated by selective laser melting.

Radiographic evaluation of bone adaptation adjacent to percutaneous osseointegrated prostheses in a sheep model.

PubMed

Jeyapalina, Sujee; Beck, James Peter; Bachus, Kent N; Chalayon, Ornusa; Bloebaum, Roy D

2014-10-01

Percutaneous osseointegrated prostheses (POPs) are being investigated as an alternative to conventional socket suspension and require a radiographic followup in translational studies to confirm that design objectives are being met. In this 12-month animal study, we determined (1) radiographic signs of osseointegration and (2) radiographic signs of periprosthetic bone hypertrophy and resorption (adaptation) and (3) confirmed them with the histologic evidence of host bone osseointegration and adaptation around a novel, distally porous-coated titanium POP with a collar. A POP device was designed to fit the right metacarpal bone of sheep. Amputation and implantation surgeries (n = 14) were performed, and plane-film radiographs were collected quarterly for 12 months. Radiographs were assessed for osseointegration (fixation) and bone adaptation (resorption and hypertrophy). The cortical wall and medullary canal widths were used to compute the cortical index and expressed as a percentage. Based on the cortical index changes and histologic evaluations, bone adaptation was quantified. Radiographic data showed signs of osseointegration including those with incomplete seating against the collar attachment. Cortical index data indicated distal cortical wall thinning if the collar was not seated distally. When implants were bound proximally, bone resorbed distally and the diaphyseal cortex hypertrophied. Histopathologic evidence and cortical index measurements confirmed the radiographic indications of adaptation and osseointegration. Distal bone loading, through collar attachment and porous coating, limited the distal bone resorption. Serial radiographic studies, in either animal models or preclinical trials for new POP devices, will help to determine which designs are likely to be safe over time and avoid implant failures.

Radiological features of the skull in Klinefelter's syndrome and male hypogonadism.

PubMed

Kosowicz, J; Rzymski, K

1975-07-01

Skull radiographs were performed in 21 cases of Klinefelter's syndrome and in 30 cases of eunuchoidism. The radiographic changes of the skull in Klinefelter's syndrome are: temporal flattening, decreased width of the vault, narrowing of the mandible, decreased length of the skull, shortening of the anterior fossa cranii, decrease in the angle of the base, thinning of the vault bones at the major fontanelle, premature and excessive calcification of the coronal suture, deepening of the posterior fossa and shortening of the mandibular rami. In hypogonadotropic eunuchoidism the skull radiographs show: small mastoid processes, fine bones of the vault, small sella turcica, club-shaped clinoid processes, excessive development of sphenoidal sinuses and in the fourth and later decades of life a diminished bone density (osteoporosis).

A Review of In-Office Dynamic Image Navigation for Extraction of Complex Mandibular Third Molars.

PubMed

Emery, Robert W; Korj, Oxana; Agarwal, Ravi

2017-08-01

We performed a retrospective review of in-office removal of complex mandibular third molars with a dynamic image navigation system (DINS). A retrospective review was conducted of cases completed from 2010 to 2014 by a single oral and maxillofacial surgeon. The average age of the patients was 47 years (range, 27 to 72 years). Extraction complexity was classified with Juodzbalys and Daugela's classification system. The included study cases had complexity scores of 9 or greater. Each patient received custom intraoral splints to secure the tracking array and underwent cone beam computed tomography image acquisition. All surgical procedures were performed with a precalibrated tracking straight handpiece under dynamic navigation. All 25 cases were treated successfully with the use of the DINS. Twelve of these cases were associated with pathologic lesions. Three patients were noted to have inferior alveolar nerve paresthesia. One patient sustained a pathologic fracture at week 2. Postoperative infections were noted in 7 cases, 2 of which had a pre-existing infection. One patient reported temporary limitation of mouth opening. A coronectomy was performed in 1 case. We present results using a new technology, the DINS, for removal of complex mandibular third molars. Potential advantages are 1) improved visualization and localization of anatomic structures such as the inferior alveolar nerve, lingual cortical plate, and adjacent roots; 2) improved control during osteotomy; 3) decreased surgical access requirements and reduction in overall bone removal; 4) ability to perform complex procedures successfully in an in-office setting; 5) decreased surgical time resulting from improved visualization; and 6) potential use as a teaching tool. Possible limitations of the use of an in-office DINS include increased cost, increased time attributed to presurgical planning, initial learning curve, and optical array interference by the surgeon or assistants during surgery. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

In vivo imaging of cortical pathology in multiple sclerosis using ultra-high field MRI

PubMed Central

Mainero, C; Benner, T; Radding, A; van der Kouwe, A; Jensen, R; Rosen, B R.; Kinkel, R P.

2009-01-01

Objective: We used ultra-high field MRI to visualize cortical lesion types described by neuropathology in 16 patients with multiple sclerosis (MS) compared with 8 age-matched controls; to characterize the contrast properties of cortical lesions including T2*, T2, T1, and phase images; and to investigate the relationship between cortical lesion types and clinical data. Methods: We collected, on a 7-T scanner, 2-dimensional fast low-angle shot (FLASH)-T2*-weighted spoiled gradient-echo, T2-weighted turbo spin-echo (TSE) images (0.33 × 033 × 1 mm3), and a 3-dimensional magnetization-prepared rapid gradient echo. Results: Overall, 199 cortical lesions were detected in patients on both FLASH-T2* and T2-TSE scans. Seven-tesla MRI allowed for characterization of cortical plaques into type I (leukocortical), type II (intracortical), and type III/IV (subpial extending partly or completely through the cortical width) lesions as described histopathologically. Types III and IV were the most frequent type of cortical plaques (50.2%), followed by type I (36.2%) and type II (13.6%) lesions. Each lesion type was more frequent in secondary progressive than in relapsing–remitting MS. This difference, however, was significant only for type III/IV lesions. T2*-weighted images showed the highest, while phase images showed the lowest, contrast-to-noise ratio for all cortical lesion types. In patients, the number of type III/IV lesions was associated with greater disability (p < 0.02 by Spearman test) and older age (p < 0.04 by Spearman test). Conclusions: Seven-tesla MRI detected different histologic cortical lesion types in our small multiple sclerosis (MS) sample, suggesting, if validated in a larger population, that it may prove a valuable tool to assess the contribution of cortical MS pathology to clinical disability. GLOSSARY ANOVA = analysis of variance; BN = background noise; CNR = contrast-to-noise ratio; DIR = double-inversion recovery; EDSS = Expanded Disability Status Scale; FLAIR = fluid-attenuated inversion recovery; FLASH = fast low-angle shot; GM = gray matter; MPRAGE = magnetization-prepared rapid gradient echo; MR = magnetic resonance; MS = multiple sclerosis; NACGM = normal-appearing cortical gray matter; RF = radiofrequency; ROI = region of interest; RRMS = relapsing–remitting multiple sclerosis; SNR = signal-to-noise ratio; SPMS = secondary progressive multiple sclerosis; TA = time of acquisition; TE = echo time; TR = repetition time; TSE = turbo spin-echo; WM = white matter. PMID:19641168

The role of simultaneous gap arthroplasty and distraction osteogenesis in the management of temporo-mandibular joint ankylosis with mandibular deformity in children.

PubMed

Rao, Krishna; Kumar, Sudhir; Kumar, Vijay; Singh, Arun Kumar; Bhatnagar, Sudhir Kumar

2004-02-01

Temporo-mandibular joint ankylosis is a common cause of acquired deformity in children. Surgical correction of the ankylosis only leaves the patient with an uncorrected mandibular deformity. This study was to evaluate the use of distraction osteogenesis for simultaneous correction of the mandibular deformity. This study was done on six children with temporo-mandibular joint ankylosis and mandibular deformity. Uniaxial double pin distractors with Schanz pins were used in this study. The patients underwent simultaneous gap arthroplasty and mandibular osteotomy (retromolar) with distractor insertion. Distraction was started on the fifth post-operative day. The patients were put on dynamic temporo-mandibular joint exercises on the first post-operative day. All patients had a satisfactory mouth opening on follow-up. Satisfactory cosmetic correction of the mandibular deformity was also achieved in all these patients. Some degree of malocclusion resulted from treatment due to which the patients were placed on orthodontic treatment. Distraction osteogenesis can be used simultaneously with gap arthroplasty in patients with temporo-mandibular ankylosis, for the correction of the mandibular deformity.

How does tooth eruption relate to vertical mandibular growth displacement?

PubMed

Liu, Sean Shih-Yao; Buschang, Peter H

2011-06-01

Our objectives were to investigate the eruptive patterns of the mandibular teeth and assess their associations with mandibular growth displacements. Cephalograms for a mixed-longitudinal sample of 124 French-Canadian girls were evaluated between 10 and 15 years of age. Vertical mandibular displacement and mandibular eruption were evaluated by using cranial and mandibular superimpositions, respectively. Multilevel modeling procedures were used to estimate each subject's growth change over time. Stepwise multiple regressions were used to determine the amount and relative magnitudes of variations in mandibular eruption explained by mandibular growth displacement, controlling for vertical maxillary tooth movements. Cubic polynomial models explained between 91% and 98% of the variations in eruption and vertical growth displacement. All curves showed acceleration of eruption until approximately 12 years of age, after which eruption decelerated. The eruption of the mandibular teeth demonstrated greater relative variability than did vertical mandibular growth displacements. Independent of the overall movements of the maxillary molars, inferior mandibular growth displacement explained approximately 54% of the variation in mandibular molar eruption between 10.5 and 14.5 years of age. Inferior mandibular growth displacement and dental eruption followed similar patterns of change during adolescence. Based on their associations and the differences in variability identified, mandibular eruption appears to compensate for or adapt to growth displacements. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

[Orthodontic treatment of Class III patients with mandibular asymmetry].

PubMed

Duan, Yin-Zhong; Huo, Na; Chen, Lei; Chen, Xue-Peng; Lin, Yang

2008-12-01

To investigate the treatment outcome of Class III patients with dental, functional and mild skeletal mandibular asymmetry. Thirty-five patients (14 males and 21 females) with dental, functional and mild skeletal mandibular asymmetry were selected. The age range of the patients was 7 - 22 years with a mean age of 16.5 years. Dental mandibular asymmetry was treated with expansion of maxillary arch to help the mandible returning to normal position. Functional mandibular asymmetry was treated with activator or asymmetrical protraction and Class III elastics. Mild skeletal mandibular asymmetry was treated with camouflage treatment. Good occlusal relationships were achieved and facial esthetics was greatly improved after orthodontic treatment in patients with dental and functional mandibular asymmetry. However, patients with skeletal mandibular asymmetry should be treated with both extraction and genioplasty. Orthodontic treatment was suitable for patients with dental and functional mandibular asymmetry, while combined orthodontics and surgery could get good results in patients with skeletal mandibular asymmetry.

Biomechanical Consequences of the Elastic Properties of Dental Implant Alloys on the Supporting Bone: Finite Element Analysis

PubMed Central

Chávarri-Prado, David; Jiménez-Garrudo, Antonio; Solaberrieta-Méndez, Eneko; Diéguez-Pereira, Markel; Fernández-González, Felipe J.; Dehesa-Ibarra, Borja; Monticelli, Francesca

2016-01-01

The objective of the present study is to evaluate how the elastic properties of the fabrication material of dental implants influence peri-implant bone load transfer in terms of the magnitude and distribution of stress and deformation. A three-dimensional (3D) finite element analysis was performed; the model used was a section of mandibular bone with a single implant containing a cemented ceramic-metal crown on a titanium abutment. The following three alloys were compared: rigid (Y-TZP), conventional (Ti-6Al-4V), and hyperelastic (Ti-Nb-Zr). A 150-N static load was tested on the central fossa at 6° relative to the axial axis of the implant. The results showed no differences in the distribution of stress and deformation of the bone for any of the three types of alloys studied, mainly being concentrated at the peri-implant cortical layer. However, there were differences found in the magnitude of the stress transferred to the supporting bone, with the most rigid alloy (Y-TZP) transferring the least stress and deformation to cortical bone. We conclude that there is an effect of the fabrication material of dental implants on the magnitude of the stress and deformation transferred to peri-implant bone. PMID:27995137

Chondroblastic osteosarcoma mimicking periapical abscess.

PubMed

Yamamoto-Silva, Fernanda Paula; Silva, Brunno Santos de Freitas; Batista, Aline Carvalho; Mendonça, Elismauro Francisco de; Pinto-Júnior, Décio Dos Santos; Estrela, Carlos

2017-01-01

The present report describes a case of chondroblastic osteosarcoma in the periapical region of teeth #29, #30, and #31 of an 18-year-old male. Clinical history showed self-reported discomfort in the right posterior gingiva for over a month. Physical examination showed a small expansion and redness of the right mandibular buccal and lingual cortical plates, but no signs of pain or inflammation were observed. All the teeth responded positively to pulp sensibility. Periapical and panoramic radiographs showed slight periapical radiolucency in the roots of teeth #29 and #30, clear periodontal ligament space widening, and evident loss of lamina dura. Incisional biopsy was performed, and based on microscopic findings the diagnosis of chondroblastic osteosarcoma was confirmed. Non-endodontic diseases associated with tooth root apex, such as chondroblastic osteosarcoma, should be included in differential diagnosis of jaw lesions that resemble periapical abscess.

Bone mineral content in the senescent rat femur: an assessment using single photon absorptiometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiebzak, G.M.; Smith, R.; Howe, J.C.

1988-06-01

The single photon absorptiometry technique was evaluated for measuring bone mineral content (BMC) of the excised femurs of the rat, and the system was used to examine the changes in cortical and trabecular bone from young adult (6 mo), mature adult (12 mo), and senescent (24 mo) male and female animals. BMC of the femur midshaft, representing cortical bone, apparently increased progressively with advancing age. The width of the femur at the scan site also increased with age. Normalizing the midshaft BMC by width partially compensated for the age-associated increase. However, when bone mineral values were normalized by the corticalmore » area at the scan site, to take into account the geometric differences in the femurs of different aged animals, maximum bone densities were found in the mature adult and these values decreased slightly in the femurs from senescent rats. In contrast, the BMC of the femur distal metaphysis, representing trabecular bone, decreased markedly in the aged rat. The loss of trabecular bone was also evident from morphological examination of the distal metaphysis. These findings indicated that bone mineral loss with age was site specific in the rat femur. These studies provided additional evidence that the rat might serve as a useful animal model for specific experiments related to the pathogenesis of age-associated osteopenia.« less

Canal Transportation, Unprepared Areas, and Dentin Removal after Preparation with BT-RaCe and ProTaper Next Systems.

PubMed

Brasil, Sabrina C; Marceliano-Alves, Marília F; Marques, Márcia L; Grillo, João P; Lacerda, Mariane F L S; Alves, Flávio R F; Siqueira, José F; Provenzano, José C

2017-10-01

This study compared the shaping ability of ProTaper Next (Dentsply Sirona, Tulsa, OK) and BT-RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instrument systems in the mesial canals of mandibular molars using micro-computed tomographic (micro-CT) imaging. A total of 17 type IV mesial roots of extracted first mandibular molars were scanned using micro-CT imaging before and after root canal preparation with the 2 instrument systems. Both systems were used in the same root but alternating the mesial canals from root to root. The following parameters were analyzed: root canal volume, surface area, unprepared surface areas, transportation, canal/root width ratio, and preparation time. There were no statistically significant differences between the 2 systems for all evaluated parameters (P > .05). The unprepared surface areas for the full canal length and the apical 5-mm segment were 33% and 14% for BT-RaCe and 31% and 14% for ProTaper Next, respectively. After preparation, all root canals had a diameter that was not larger than 35% of the root diameter at the coronal and middle segments. The 2 systems showed no differences in any of the evaluated shaping parameters. None of the tested systems put the roots at risk of fracture because of excessive dentin removal. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Slow cortical potentials and "inner time consciousness" - A neuro-phenomenal hypothesis about the "width of present".

PubMed

Northoff, Georg

2016-05-01

William James postulated a "stream of consciousness" that presupposes temporal continuity. The neuronal mechanisms underlying the construction of such temporal continuity remain unclear, however, in my contribution, I propose a neuro-phenomenal hypothesis that is based on slow cortical potentials and their extension of the present moment as described in the phenomenal term of "width of present". More specifically, I focus on the way the brain's neural activity needs to be encoded in order to make possible the "stream of consciousness." This leads us again to the low-frequency fluctuations of the brain's neural activity and more specifically to slow cortical potentials (SCPs). Due to their long phase duration as low-frequency fluctuations, SCPs can integrate different stimuli and their associated neural activity from different regions in one converging region. Such integration may be central for consciousness to occur, as it was recently postulated by He and Raichle. They leave open, however, the question of the exact neuronal mechanisms, like the encoding strategy, that make possible the association of the otherwise purely neuronal SCP with consciousness and its phenomenal features. I hypothesize that SCPs allow for linking and connecting different discrete points in physical time by encoding their statistically based temporal differences rather than the single discrete time points by themselves. This presupposes difference-based coding rather than stimulus-based coding. The encoding of such statistically based temporal differences makes it possible to "go beyond" the merely physical features of the stimuli; that is, their single discrete time points and their conduction delays (as related to their neural processing in the brain). This, in turn, makes possible the constitution of "local temporal continuity" of neural activity in one particular region. The concept of "local temporal continuity" signifies the linkage and integration of different discrete time points into one neural activity in a particular region. How does such local temporal continuity predispose the experience of time in consciousness? For that, I turn to phenomenological philosopher Edmund Husserl and his description of what he calls "inner time consciousness" (Husserl and Brough, 1990). One hallmark of humans' "inner time consciousness" is that we experience events and objects in succession and duration in our consciousness; according to Husserl, this amounts to what he calls the "width of [the] present." The concept of the width of present describes the extension of the present beyond the single discrete time point, such as, for instance, when we perceive different tones as a melody. I now hypothesize the degree of the width of present to be directly dependent upon and thus predisposed by the degree of the temporal differences between two (or more) discrete time points as they are encoded into neural activity. I therefore conclude that the SCPs and their encoding of neural activity in terms of temporal differences must be regarded a neural predisposition of consciousness (NPC) as distinguished from a neural correlate of consciousness (NCC). Copyright © 2015 Elsevier B.V. All rights reserved.

Rotational Distraction for the Treatment of Severe Mandibular Retrognathia

PubMed Central

Mitsugi, Masaharu; Alcalde, Rafael E.; Yano, Tomoyuki; Uemura, Noriko; Okazaki, Mutsumi

2015-01-01

Backgrounds: The main problem with intraoral distraction of the mandible is the inability to achieve the three-dimensional mandibular correction as planned preoperatively. We developed a technique that allows spontaneous changes in the direction of mandibular elongation using an intraoral distractor. Methods: After mandibular osteotomy, the distractor is fixed to the distal segment of the mandible using a single bicortical screw, allowing anterior-posterior, vertical and limited lateromedial changes in the vector of distraction. Mandibular lengthening is performed while keeping the maxilla and mandible in class I occlusion with intermaxillary fixation. Results: As the distraction device is activated allowing mandibular elongation, the proximal segment, guided by the surrounding soft tissues, moves and rotates posterosuperiorly. Mandibular lengthening is continued until the condylar head reaches an adequate position in the mandibular fossa as confirmed clinically and radiographically. Conclusion Thirty-three patients with mandibular retrognathia received this treatment and good results were obtained. PMID:26301156

Rotational Distraction for the Treatment of Severe Mandibular Retrognathia.

PubMed

Ito, Osamu; Mitsugi, Masaharu; Alcalde, Rafael E; Yano, Tomoyuki; Uemura, Noriko; Okazaki, Mutsumi

2015-07-01

The main problem with intraoral distraction of the mandible is the inability to achieve the three-dimensional mandibular correction as planned preoperatively. We developed a technique that allows spontaneous changes in the direction of mandibular elongation using an intraoral distractor. After mandibular osteotomy, the distractor is fixed to the distal segment of the mandible using a single bicortical screw, allowing anterior-posterior, vertical and limited lateromedial changes in the vector of distraction. Mandibular lengthening is performed while keeping the maxilla and mandible in class I occlusion with intermaxillary fixation. As the distraction device is activated allowing mandibular elongation, the proximal segment, guided by the surrounding soft tissues, moves and rotates posterosuperiorly. Mandibular lengthening is continued until the condylar head reaches an adequate position in the mandibular fossa as confirmed clinically and radiographically. Thirty-three patients with mandibular retrognathia received this treatment and good results were obtained.

[Influence of the mandibular second premolar extraction on the angulation of the mandibular third molar].

PubMed

Feng, Guang-yao; Zou, Bing-shuang; Gao, Xue-mei; Zeng, Xiang-long; Wang, Xiu-jing; Yan, Yan

2013-02-18

To compare the angular changes in the developing mandibular third molars in the mandibular second premolar extraction and non-extraction cases and to determine whether the mandibular second premolar extraction causes favorable rotational changes in the angulations of the developing mandibular third molars and benefits its later eruption. Pretreatment and posttreatment panoramic radiographs were taken from 45 subjects who had been treated by the extraction of the mandibular second premolars and 48 subjects who had been treated without extraction. The horizontal reference plane was used to measure and compare the changes in the angulations of the developing mandibular third molars. The mean uprighting of the mandibular third molars seen in the extraction group was (5.9±2.5) degrees on the right side and (8.0±3.4) degrees on the left side following treatment. For the nonextraction group the mean uprighting was (1.8±2.4) degrees on the right side and (1.5±2.1) degrees on the left side. There was a statistically significant difference between the groups (P<0.05). Mandibular second premolar extraction might be a helpful procedure on the angulations of the developing mandibular third molars.

Comparison of different grafting materials for treatment of bone defect distal to the molar in canine.

PubMed

Ge, Jing; Yang, Chi; Wang, Yong; Zheng, Jiawei; Hua, Hongfei; Zhu, Jun

2018-03-25

The extraction of impacted mandibular 3rd molar is highly related to bone defect distal to the adjacent 2nd molar. The aim of this study was to evaluate the effect of different grafting materials for the treatment of bone defect distal to the mandibular molar in canine model. In 12 beagle dogs, bilateral mandibular 2nd and 3rd molars were extracted and entire mesial bone of the 2nd molar extracted socket was surgically removed. Twenty-four bone defects (4 mm width and 8 mm depth) were randomly assigned to 4 groups, and grafted using 1 of the following protocols: (1) group C: no graft; (2) group Ta: autogenous bone (AB); (3) group Tb: deproteinized bovine bone mineral (DBBM) with a collagen membrane (CM); and (4) group Tab: an equal mixture of AB/DBBM + CM. Quantitative imageology analyses using micro-CT and fluorescence microscopy, as well as qualitative analyses using histological and histomorphometric evaluations, were characterized at postoperative 12 weeks. Significant differences of all variables were tested by multivariate analysis (P < .05). The defect depth was significantly lower in groups Ta, Tb, and Tab (1.70, 1.97, and 1.61 mm, respectively; mean) than in the group C (3.66 mm, P < .01, all). Compared to the sites received DBBM/CM, sites grafted with AB or AB/DBBM exhibited significant greater and faster new bone formation (P < .01). The percentage of DBBM remnants area (%) was significantly higher in group Tb than in group Tab (10.43% and 1.13%, P < .01; mean). Our data suggested grafting AB alone, DBBM/CM, or AB/DBBM/CM resulted in similar periodontal parameters in canine. Furthermore, the AB could accelerate new bone regeneration and mineralization, and promote the biodegradation of DBBM. © 2018 Wiley Periodicals, Inc.

Relationship between mandibular anatomy and the occurrence of a bad split upon sagittal split osteotomy.

PubMed

Aarabi, Mohammadali; Tabrizi, Reza; Hekmat, Mina; Shahidi, Shoaleh; Puzesh, Ayatollah

2014-12-01

A bad split is a troublesome complication of the sagittal split osteotomy (SSO). The aim of this study was to evaluate the relation between the occurrence of a bad split and mandibular anatomy in SSO using cone-beam computed tomography. The authors designed a cohort retrospective study. Forty-eight patients (96 SSO sites) were studied. The buccolingual thickness of the retromandibular area (BLR), the buccolingual thickness of the ramus at the level of the lingula (BLTR), the height of the mandible from the alveolar crest to the inferior border of the mandible, (ACIB), the distance between the sigmoid notch and the inferior border of the mandible (SIBM), and the anteroposterior width of the ramus (APWR) were measured. The independent t test was applied to compare anatomic measurements between the group with and the group without bad splits. The receiver operating characteristic (ROC) test was used to find a cutoff point in anatomic size for various parts of the mandible related to the occurrence of bad splits. The mean SIBM was 47.05±6.33 mm in group 1 (with bad splits) versus 40.66±2.44 mm in group 2 (without bad splits; P=.01). The mean BLTR was 5.74±1.11 mm in group 1 versus 3.19±0.55 mm in group 2 (P=.04). The mean BLR was 14.98±2.78 mm in group 1 versus 11.21±1.29 mm in group 2 (P=.001). No statistically significant difference was found for APWR and ACIB between the 2 groups. The ROC test showed cutoff points of 10.17 mm for BLR, 36.69 mm for SIBM, and 4.06 mm for BLTR. This study showed that certain mandibular anatomic differences can increase the risk of a bad split during SSO surgery. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Prevalence of Temporal Bone Fractures in Patients with Mandibular Fractures Using Multidetector-Row CT.

PubMed

Ogura, I; Kaneda, T; Sasaki, Y; Buch, K; Sakai, O

2015-06-01

Temporal bone fracture after mandibular trauma is thought to be rare, and its prevalence has not been reported in the literature. The purpose of this study was to investigate the prevalence of temporal bone fractures in patients with mandibular fractures and the relationship between temporal bone fractures and the mandibular fracture location using multidetector-row computed tomography (MDCT). A prospective study was performed in 201 patients with mandibular fractures who underwent 64-MDCT scans. The mandibular fracture locations were classified as median, paramedian, angle, and condylar types. Statistical analysis for the relationship between prevalence of temporal bone fractures and mandibular fracture locations was performed using χ(2) test with Fisher's exact test. A P-value < 0.05 was considered statistically significant. The percentage of cases with temporal bone fracture was 3.0 % of all patients with mandibular fractures and 19.0 % of those with multiple mandibular fractures of paramedian and condylar type. There was a significant relationship between the incidence of temporal bone fracture and the paramedian- and condylar-type mandibular fracture (P = 0.001). Multiple mandibular fractures of paramedian and condylar type may be a stronger indicator for temporal bone fractures. This study suggests that patients with mandibular fracture, especially the paramedian and condylar type, should be examined for coexisting temporal bone fracture using MDCT.

Do flexible acrylic resin lingual flanges improve retention of mandibular complete dentures?

PubMed Central

Ahmed Elmorsy, Ayman Elmorsy; Ahmed Ibraheem, Eman Mostafa; Ela, Alaa Aboul; Fahmy, Ahmed; Nassani, Mohammad Zakaria

2015-01-01

Objectives: The aim of this study was to compare the retention of conventional mandibular complete dentures with that of mandibular complete dentures having lingual flanges constructed with flexible acrylic resin “Versacryl.” Materials and Methods: The study sample comprised 10 completely edentulous patients. Each patient received one maxillary complete denture and two mandibular complete dentures. One mandibular denture was made of conventional heat-cured acrylic resin and the other had its lingual flanges made of flexible acrylic resin Versacryl. Digital force-meter was used to measure retention of mandibular dentures at delivery and at 2 weeks and 45 days following denture insertion. Results: The statistical analysis showed that at baseline and follow-up appointments, retention of mandibular complete dentures with flexible lingual flanges was significantly greater than retention of conventional mandibular dentures (P < 0.05). In both types of mandibular dentures, retention of dentures increased significantly over the follow-up period (P < 0.05). Conclusions: The use of flexible acrylic resin lingual flanges in the construction of mandibular complete dentures improved denture retention. PMID:26539387

Computational modeling of epidural cortical stimulation

NASA Astrophysics Data System (ADS)

Wongsarnpigoon, Amorn; Grill, Warren M.

2008-12-01

Epidural cortical stimulation (ECS) is a developing therapy to treat neurological disorders. However, it is not clear how the cortical anatomy or the polarity and position of the electrode affects current flow and neural activation in the cortex. We developed a 3D computational model simulating ECS over the precentral gyrus. With the electrode placed directly above the gyrus, about half of the stimulus current flowed through the crown of the gyrus while current density was low along the banks deep in the sulci. Beneath the electrode, neurons oriented perpendicular to the cortical surface were depolarized by anodic stimulation, and neurons oriented parallel to the boundary were depolarized by cathodic stimulation. Activation was localized to the crown of the gyrus, and neurons on the banks deep in the sulci were not polarized. During regulated voltage stimulation, the magnitude of the activating function was inversely proportional to the thickness of the CSF and dura. During regulated current stimulation, the activating function was not sensitive to the thickness of the dura but was slightly more sensitive than during regulated voltage stimulation to the thickness of the CSF. Varying the width of the gyrus and the position of the electrode altered the distribution of the activating function due to changes in the orientation of the neurons beneath the electrode. Bipolar stimulation, although often used in clinical practice, reduced spatial selectivity as well as selectivity for neuron orientation.

Spectral integration in primary auditory cortex attributable to temporally precise convergence of thalamocortical and intracortical input.

PubMed

Happel, Max F K; Jeschke, Marcus; Ohl, Frank W

2010-08-18

Primary sensory cortex integrates sensory information from afferent feedforward thalamocortical projection systems and convergent intracortical microcircuits. Both input systems have been demonstrated to provide different aspects of sensory information. Here we have used high-density recordings of laminar current source density (CSD) distributions in primary auditory cortex of Mongolian gerbils in combination with pharmacological silencing of cortical activity and analysis of the residual CSD, to dissociate the feedforward thalamocortical contribution and the intracortical contribution to spectral integration. We found a temporally highly precise integration of both types of inputs when the stimulation frequency was in close spectral neighborhood of the best frequency of the measurement site, in which the overlap between both inputs is maximal. Local intracortical connections provide both directly feedforward excitatory and modulatory input from adjacent cortical sites, which determine how concurrent afferent inputs are integrated. Through separate excitatory horizontal projections, terminating in cortical layers II/III, information about stimulus energy in greater spectral distance is provided even over long cortical distances. These projections effectively broaden spectral tuning width. Based on these data, we suggest a mechanism of spectral integration in primary auditory cortex that is based on temporally precise interactions of afferent thalamocortical inputs and different short- and long-range intracortical networks. The proposed conceptual framework allows integration of different and partly controversial anatomical and physiological models of spectral integration in the literature.

Modeling Early Cortical Serotonergic Deficits in Autism

PubMed Central

Boylan, Carolyn B.; Blue, Mary E.; Hohmann, Christine F.

2007-01-01

Autism is a developmental brain disorder characterized by deficits in social interaction, language and behavior. Brain imaging studies demonstrate increased cerebral cortical volumes and micro- and macroscopic neuroanatomic changes in children with this disorder. Alterations in forebrain serotonergic function may underlie the neuroanatomic and behavioral features of autism. Serotonin is involved in neuronal growth and plasticity and these actions are likely mediated via serotonergic and glutamatergic receptors. Few animal models of autism have been described that replicate both etiology and pathophysiology. We report here on a selective serotonin (5-HT) depletion model of this disorder in neonatal mice that mimics neurochemical and structural changes in cortex and, in addition, displays a behavioral phenotype consistent with autism. Newborn male and female mice were depleted of forebrain 5-HT with injections of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), into the bilateral medial forebrain bundle (mfb). Behavioral testing of these animals as adults revealed alterations in social, sensory and stereotypic behaviors. Lesioned mice showed significantly increased cortical width. Serotonin immunocytochemistry showed a dramatic long-lasting depletion of 5-HT containing fibers in cerebral cortex until postnatal day (PND) 60. Autoradiographic binding to high affinity 5-HT transporters was significantly but transiently reduced in cerebral cortex of 5,7-DHT-depleted mice. AMPA glutamate receptor binding was decreased at PND 15. We hypothesize that increased cerebral cortical volume and sensorimotor, cognitive and social deficits observed in both 5-HT-depleted animals and in individuals with autism, may be the result of deficiencies in timely axonal pruning to key cerebral cortical areas. PMID:17034875

Modeling early cortical serotonergic deficits in autism.

PubMed

Boylan, Carolyn B; Blue, Mary E; Hohmann, Christine F

2007-01-10

Autism is a developmental brain disorder characterized by deficits in social interaction, language and behavior. Brain imaging studies demonstrate increased cerebral cortical volumes and micro- and macro-scopic neuroanatomic changes in children with this disorder. Alterations in forebrain serotonergic function may underlie the neuroanatomic and behavioral features of autism. Serotonin is involved in neuronal growth and plasticity and these actions are likely mediated via serotonergic and glutamatergic receptors. Few animal models of autism have been described that replicate both etiology and pathophysiology. We report here on a selective serotonin (5-HT) depletion model of this disorder in neonatal mice that mimics neurochemical and structural changes in cortex and, in addition, displays a behavioral phenotype consistent with autism. Newborn male and female mice were depleted of forebrain 5-HT with injections of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), into the bilateral medial forebrain bundle (mfb). Behavioral testing of these animals as adults revealed alterations in social, sensory and stereotypic behaviors. Lesioned mice showed significantly increased cortical width. Serotonin immunocytochemistry showed a dramatic long-lasting depletion of 5-HT containing fibers in cerebral cortex until postnatal day (PND) 60. Autoradiographic binding to high affinity 5-HT transporters was significantly but transiently reduced in cerebral cortex of 5,7-DHT-depleted mice. AMPA glutamate receptor binding was decreased at PND 15. We hypothesize that increased cerebral cortical volume and sensorimotor, cognitive and social deficits observed in both 5-HT-depleted animals and in individuals with autism, may be the result of deficiencies in timely axonal pruning to key cerebral cortical areas.

Influence of different abutment diameter of implants on the peri-implant stress in the crestal bone: A three-dimensional finite element analysis--In vitro study.

PubMed

Aradya, Anupama; Kumar, U Krishna; Chowdhary, Ramesh

2016-01-01

The study was designed to evaluate and compare stress distribution in transcortical section of bone with normal abutment and platform switched abutment under vertical and oblique forces in posterior mandible region. A three-dimensional finite element model was designed using ANSYS 13.0 software. The type of bone selection for the model was made of type II mandibular bone, having cortical bone thickness ranging from 0.595 mm to 1.515 mm with the crestal region measuring 1.5 mm surrounding dense trabecular bone. The implant will be modulated at 5 mm restorative platform and tapering down to 4.5 mm wide at the threads, 13 mm long with an abutment 3 mm in height. The models will be designed for two situations: (1) An implant with a 5 mm diameter abutment representing a standard platform in the posterior mandible region. (2) An implant with a 4.5 mm diameter abutment representing platform switching in the posterior mandible region. Force application was performed in both oblique and vertical conditions using 100 N as a representative masticatory force. For oblique loading, a force of 100 N was applied at 15° from the vertical axis. von Mises stress analysis was evaluated. The results of the study showed cortical stress in the conventional and platform switching model under oblique forces were 59.329 MPa and 39.952 MPa, respectively. Cortical stress in the conventional and platform switching model under vertical forces was 13.914 MPa and 12.793 MPa, respectively. Results from this study showed the platform switched abutment led to relative decrease in von Mises stress in transcortical section of bone compared to normal abutment under vertical and oblique forces in posterior mandible region.

21 CFR 872.4770 - Temporary mandibular condyle reconstruction plate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... device that is intended to stabilize mandibular bone and provide for temporary reconstruction of the... surgical procedures requiring removal of the mandibular condyle and mandibular bone. This device is not...

Signaling pathways regulating the expression of Prx1 and Prx2 in the Chick Mandibular Mesenchyme

PubMed Central

Doufexi, Aikaterini-El; Mina, Mina

2009-01-01

Prx1 and Prx2 are members of the aristaless-related homeobox genes shown to play redundant but essential roles in morphogenesis of the mandibular processes. To gain insight into the signaling pathways that regulate expression of Prx genes in the mandibular mesenchyme, we used the chick as a model system. We examined the patterns of gene expression in the face and the roles of signals derived from the epithelium on the expression of Prx genes in the mandibular mesenchyme. Our results demonstrated stage-dependent roles of mandibular epithelium on the expression of Prx in the mandibular mesenchyme and provide evidence for positive roles of members of the fibroblast and hedgehog families derived from mandibular epithelium on the expression of Prx genes in the mandibular mesenchyme. Our studies suggest that endothelin-1 signaling derived from the mesenchyme is involved in restricting the expression of Prx2 to the medial mandibular mesenchyme. PMID:18942149

The use of the mandibular infiltration anesthetic technique in adults.

PubMed

Meechan, John G

2011-09-01

The author describes the use of the infiltration anesthetic technique to anesthetize mandibular teeth in adults and explores its mechanism of action. The author reviewed articles describing randomized controlled trials of the mandibular infiltration anesthetic technique in healthy participants. The author found that using the mandibular infiltration anesthetic technique can produce anesthesia in adult mandibular teeth. The success was dose dependent and the choice of anesthetic solution was significant; 4 percent articaine with 1:100,000 epinephrine was more effective than 2 percent lidocaine with 1:100,000 epinephrine. Combining buccal and lingual infiltrations increased success in the mandibular incisor region. The success of the mechanism of infiltration of anesthetic at the mandibular first molar appeared to depend on the mental foramen. The mandibular infiltration anesthetic technique is an effective method of anesthetizing mandibular incisors. Four percent articaine with epinephrine appears to be the preferred solution. The choice of anesthetic solution is important when using the infiltration anesthetic technique in the adult mandible.

Dark-field transmission electron microscopy of cortical bone reveals details of extrafibrillar crystals.

PubMed

Schwarcz, Henry P; McNally, Elizabeth A; Botton, Gianluigi A

2014-12-01

In a previous study we showed that most of the mineral in bone is present in the form of "mineral structures", 5-6nm-thick, elongated plates which surround and are oriented parallel to collagen fibrils. Using dark-field transmission electron microscopy, we viewed mineral structures in ion-milled sections of cortical human bone cut parallel to the collagen fibrils. Within the mineral structures we observe single crystals of apatite averaging 5.8±2.7nm in width and 28±19nm in length, their long axes oriented parallel to the fibril axis. Some appear to be composite, co-aligned crystals as thin as 2nm. From their similarity to TEM images of crystals liberated from deproteinated bone we infer that we are viewing sections through platy crystals of apatite that are assembled together to form the mineral structures. Copyright © 2014 Elsevier Inc. All rights reserved.

Heritability of Craniofacial Structures in Normal Subjects and Patients with Sleep Apnea

PubMed Central

Chi, Luqi; Comyn, Francois-Louis; Keenan, Brendan T.; Cater, Jacqueline; Maislin, Greg; Pack, Allan I.; Schwab, Richard J.

2014-01-01

Objectives: Accumulating evidence has shown that there is a genetic contribution to obstructive sleep apnea (OSA).The objectives were to use magnetic resonance imaging (MRI) cephalometry to (1) confirm heritability of craniofacial risk factors for OSA previously shown by cephalometrics; and (2) examine the heritability of new craniofacial structures that are measurable with MRI. Design: A sib pair “quad” design examining apneics, apneic siblings, controls, and control siblings. The study design used exact matching on ethnicity and sex, frequency matching on age, and statistical control for differences in age, sex, ethnicity, height, and weight. Setting: Academic medical center. Patients: We examined 55 apneic probands (apnea-hypopnea index [AHI]: 46.8 ± 33.5 events/h), 55 proband siblings (AHI: 11.1 ± 15.9 events/h), 55 controls (AHI: 2.2 ± 1.7 events/h), and 55 control siblings (AHI: 4.1 ± 4.0 events/h). Interventions: N/A. Measurements and Results: Five independent domains reflecting different aspects of the craniofacial structure were examined. We confirmed heritability of sella–nasion–subspinale (38%, P = 0.002), saddle angle (55%, P < 0.0001), mandibular length (24%, P = 0.02) and lower facial height (33%, P = 0.006) previously measured by cephalometry. In addition, the current study added new insights by demonstrating significant heritability of mandibular width (30%, P = 0.005), maxillary width (47%, P < 0.0001), distance from the hyoid bone to the retropogonion (36%, P = 0.0018) and size of the oropharyngeal space (31%, P = 0.004). Finally, our data indicate that heritability of the craniofacial structures is similar in normal patients and those with apnea. Conclusions: The data support our a priori hypothesis that the craniofacial structures that have been associated with obstructive sleep apnea (OSA) are heritable. We have demonstrated heritability for several intermediate craniofacial phenotypes for OSA. Thus, we believe that future studies should be able to identify genes associated with these intermediate craniofacial phenotypes. Citation: Chi L, Comyn FL, Keenan BT, Cater J, Maislin G, Pack AI, Schwab RJ. Heritability of craniofacial structures in normal subjects and patients with sleep apnea. SLEEP 2014;37(10):1689-1698. PMID:25197806

[Stress distribution in press-fit orthodontic microimplant bone interface].

PubMed

Wu, Jian-chao; Huang, Ji-na; Zhao, Shi-fang; Xu, Xue-jun

2006-12-01

The goal of this study is to analyse the stress distribution in the press-fit microimplant-bone interface and its indications for immediate loading of orthodontic microimplant. Three-dimensional finite element models were created of a 20 mm section of posterior mandible simplified in isosceles trapezoid shape, 30 mm in height, 10mm in upper side width, 14 mm in lower side width,with a single microimplant, 1.2 mm in diameter, 6 mm in length embedded in the bone. The cortical bone thickness was assumed as 1.6 mm. Cortical and cancellous bone were modeled as transversely isotropic and linearly elastic materials. Titanium was modeled as isotropic and linearly elastic material. Perfect bonding was assumed at microimplant- bone interfaces. ANSYS 9.0 finite element analysis software was used to generate the simplified finite element models of the local mandible-implant complex. 0 mm, 0.05 mm and 0.1 mm press-fit were arbitrarily set to the implant-bone interface to mimic the situation of immediate placement of microimplant. Stresses in the microimplant-bone interface were calculated under these "press-fit". Stresses distributed mainly in the cortical bone interface. At Omm press-fit, the stress was 0 MPa. For 0.05mm press-fit, the stress was 1648 MPa in mesio-distal direction, 1782MPa in occluso-gingival direction;and for 0.1 mm, it reached 2012MPa in mesio-distal direction, 2110MPa in occluso-gingival direction. As the "press-fit" increased, the stresses increased accordingly. Values of initial stress in the microimplant-bone interface due to press-fit generated by immediately placed microimplant were very high in these limited and simplified three dimensional finite element models. It reminded us that the initial stress be taken into consideration when immediate loading of the microimplant is planned. Supported by Research Fund of Health Bureau of Zhejiang Province (2005B104).

Morphometric study on mandibular foramen and incidence of accessory mandibular foramen in mandibles of south Indian population and its clinical implications in inferior alveolar nerve block.

PubMed

Shalini, R; RaviVarman, C; Manoranjitham, R; Veeramuthu, M

2016-12-01

The mandibular foramen is a landmark for procedures like inferior alveolar nerve block, mandibular implant treatment, and mandibular osteotomies. The present study was aimed to identify the precise location of the mandibular foramen and the incidence of accessory mandibular foramen in dry adult mandibles of South Indian population. The distance of mandibular foramen from the anterior border of the ramus, posterior border of the ramus, mandibular notch, base of the mandible, third molar, and apex of retromolar trigone was measured with a vernier caliper in 204 mandibles. The mean distance of mandibular foramen from the anterior border of ramus of mandible was 17.11±2.74 mm on the right side and 17.41±3.05 mm on the left side, from posterior border was 10.47±2.11 mm on the right side and 9.68±2.03 mm on the left side, from mandibular notch was 21.74±2.74 mm on the right side and 21.92±3.33 mm on the left side, from the base of the ramus was 22.33±3.32 mm on the right side and 25.35±4.5 mm on the left side, from the third molar tooth was 22.84±3.94 mm on the right side and 23.23±4.21 mm on the left side, from the apex of retromolar trigone was 12.27±12.13 mm on the right side and 12.13±2.35 mm on the left side. Accessory mandibular foramen was present in 32.36% of mandibles. Knowledge of location mandibular foramen is useful to the maxillofacial surgeons, oncologists and radiologists.

Morphometric study on mandibular foramen and incidence of accessory mandibular foramen in mandibles of south Indian population and its clinical implications in inferior alveolar nerve block

PubMed Central

RaviVarman, C.; Manoranjitham, R.; Veeramuthu, M.

2016-01-01

The mandibular foramen is a landmark for procedures like inferior alveolar nerve block, mandibular implant treatment, and mandibular osteotomies. The present study was aimed to identify the precise location of the mandibular foramen and the incidence of accessory mandibular foramen in dry adult mandibles of South Indian population. The distance of mandibular foramen from the anterior border of the ramus, posterior border of the ramus, mandibular notch, base of the mandible, third molar, and apex of retromolar trigone was measured with a vernier caliper in 204 mandibles. The mean distance of mandibular foramen from the anterior border of ramus of mandible was 17.11±2.74 mm on the right side and 17.41±3.05 mm on the left side, from posterior border was 10.47±2.11 mm on the right side and 9.68±2.03 mm on the left side, from mandibular notch was 21.74±2.74 mm on the right side and 21.92±3.33 mm on the left side, from the base of the ramus was 22.33±3.32 mm on the right side and 25.35±4.5 mm on the left side, from the third molar tooth was 22.84±3.94 mm on the right side and 23.23±4.21 mm on the left side, from the apex of retromolar trigone was 12.27±12.13 mm on the right side and 12.13±2.35 mm on the left side. Accessory mandibular foramen was present in 32.36% of mandibles. Knowledge of location mandibular foramen is useful to the maxillofacial surgeons, oncologists and radiologists. PMID:28127498

The efficacy of supplemental intraosseous anesthesia after insufficient mandibular block.

PubMed

Prohić, Samir; Sulejmanagić, Halid; Secić, Sadeta

2005-02-01

It is a well-known scientific fact that only a small percentage of infiltration of inferior alveolar nerve is clinically proven to be efficient. The objective of this study was to determine the anesthetic efficacy of supplemental intraosseous injection, used after the insufficient classical mandibular block that didn't provide deep pulp anesthesia of mandibular molar planed for extraction. The experimental teeth consisted of 98 mandibular molars with clinical indication for extraction. Based on the history of disease, we indicated the extraction of the tooth. After that each tooth was tested with a electric pulp tester P1. We tested the pulp vitality and precisely determined the level of vitality. After that, each patient received classical mandibular block, and the pulp vitality was tested again. If the pulp tester indicated negative vitality for the certain mandibular molar, and the patient didn't complain about pain or discomfort during the extraction, the molar was extracted and the result was added to anesthetic success rate for the classical mandibular block. If, five minutes after receiving the mandibular block, the pulp tester indicated positive vitality (parameters of vitality) or the patient complained about pain or discomfort (parameters of pain and discomfort), we used the Stabident intraosseous anesthesia system. Three minutes after the application of supplemental intraosseous injection the molar was tested with the pulp tester again. The anesthetic solution used in both anesthetic techniques is lidocaine with 1:100.000 epinephrine. The results of this study indicate that the anesthetic efficacy of the mandibular block is 74.5%, and that supplemental intraosseous anesthesia, applied after the insufficient mandibular block, provides pulpal anesthesia in 94.9% of mandibular molars. The difference between anesthetic efficacy of the classical mandibular block and anesthetic efficacy of the supplemental intraosseous anesthesia, applied after the insufficient mandibular block, is obvious.

Dental arch changes associated with rapid maxillary expansion: A retrospective model analysis study

PubMed Central

D’Souza, Ivor M; Kumar, H. C. Kiran; Shetty, K. Sadashiva

2015-01-01

Introduction: Transverse deficiency of the maxilla is a common clinical problem in orthodontics and dentofacial orthopedics. Transverse maxillary deficiency, isolated or associated with other dentofacial deformities, results in esthetic and functional impairment giving rise to several clinical manifestations such as asymmetrical facial growth, positional and functional mandibular deviations, altered dentofacial esthetics, adverse periodontal responses, unstable dental tipping, and other functional problems. Orthopedic maxillary expansion is the preferred treatment approach to increase the maxillary transverse dimension in young patients by splitting of the mid palatal suture. This orthopedic procedure has lately been subject of renewed interest in orthodontic treatment mechanics because of its potential for increasing arch perimeter to alleviate crowding in the maxillary arch without adversely affecting facial profile. Hence, the present investigation was conducted to establish a correlation between transverse expansion and changes in the arch perimeter, arch width and arch length. Methods: For this purpose, 10 subjects (five males, five females) were selected who had been treated by rapid maxillary expansion (RME) using hyrax rapid palatal expander followed by fixed mechanotherapy (PEA). Pretreatment (T1), postexpansion (T2), and posttreatment (T3) dental models were compared for dental changes brought about by RME treatment and its stability at the end of fixed mechanotherapy. After model measurements were made, the changes between T1–T2, T2–T3 and T1–T3 were determined for each patient. The mean difference between T1–T2, T2–T3 and T1–T3 were compared to assess the effects of RME on dental arch measurements. Results are expressed as mean ± standard deviation and are compared by repeated measures analysis of variance followed by a post-hoc test. Arch perimeter changes are correlated with changes in arch widths at the canine, premolar and molar regions. Results: The intercanine arch width increased by 2.9 mm, inter first premolar width increased by 3.2 mm, inter second premolar width increased by 4.6 mm, intermolar width increased by 4.4 mm, arch perimeter increased by 3.2 mm, arch length decreased by 1.8 mm from pretreatment to posttreatment. There is a strong positive correlation of arch perimeter with intercanine width (r2 = 0.99), interpremolar width (r2 = 0.99) and intermolar width (r2 = 0.98), indicating that there is a significant increase in arch perimeter with increase in arch width at the canine, premolars and molar regions. Conclusion: Findings of this study demonstrate that there was a significant increase in the intercanine, inter first premolar, inter second premolar intermolar arch width and arch perimeter from pretreatment to postexpansion, which was stable at the end of fixed mechanotherapy (PEA). There was a nonsignificant decrease in arch length from pretreatment to postexpansion that further decreased nonsignificantly from postexpansion to posttreatment. PMID:25684912

Mandibular Fracture Patterns at a Medical Center in Central Taiwan: A 3-Year Epidemiological Review.

PubMed

Lin, Fu-Yu; Wu, Chao-I; Cheng, Hsu-Tang

2017-12-01

Mandibular fractures constitute a major portion of maxillofacial trauma and may lead to considerable functional and aesthetic sequelae if treatment is inadequate or delayed. An epidemiology study on mandibular fractures may guide the preventive efforts of the Taiwan public health care system. Therefore, a retrospective review was conducted at a medical center in central Taiwan to evaluate the current mandibular fracture epidemiology.The medical records and digitized radiographs of 198 patients who received treatment for mandibular fractures during a 3-year period (from October 2010 to September 2013) at a medical center in central Taiwan were reviewed to obtain demographic and injury data.The average age was 29.4 years (3-82 years). Patients aged 21 to 30 years sustained the most mandibular fractures (62 patients, 31.3%). The overall sex distribution (male to female) ratio was 1.8. Motor-vehicle accidents (MVAs) were the most common mechanism of injury (162 patients, 82%), and scooter and motorcycle riders wearing partial-coverage helmets constituted the majority of patients. A chart review identified 198 patients with 335 mandibular fractures; 113 patients (57.1%) had multiple mandibular fractures. The most common fracture sites were the symphysis and parasymphysis regions (38.9%), followed by the condyle (26.0%), angle (14.3%), body (14.3%), and ramus (6.6%).MVAs are the major cause of mandibular fractures in central Taiwan, and patients aged <30 years sustained the most mandibular fractures. Compared with previous studies, the present study has a higher percentage of women with mandibular fractures. In addition, inadequate mandibular protection by partial-coverage helmets may be a major reason for mandibular fractures most commonly localized in the symphysis and parasymphysis regions. The incidence and causes of mandibular fractures may reflect the trauma patterns within the community, thus facilitating the development of a preventive strategy for the socioeconomic and environmental background of central Taiwan. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Comparative biomechanical evaluation of mono-cortical osteosynthesis systems for condylar fractures using photoelastic stress analysis.

PubMed

Christopoulos, Panos; Stathopoulos, Panagiotis; Alexandridis, Constantinos; Shetty, Vivek; Caputo, Angelo

2012-10-01

Fractures of the condyle account for 20-30% of all mandibular fractures, and are therefore one of the most common facial injuries. Precise evaluation of the mechanical stresses that develop in a fractured mandible is essential, particularly for the testing of systems currently used for stabilisation of the condylar fragment. Photoelastic stress analysis can be used to visualise alterations in the strain that is induced in the mandible by a fracture, and in the osteosynthesis materials used to stabilise it. This method, used on currently used osteosynthesis materials, showed that stabilisation of a subcondylar fracture with a single miniplate does not provide enough stability, whereas the use of two miniplates - properly positioned - offers sufficient stability in all loading conditions. A microplate may be used as a tension-resisting plate with equally good results. Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Cemento-ossifying fibroma of the mandible.

PubMed

Trijolet, J-P; Parmentier, J; Sury, F; Goga, D; Mejean, N; Laure, B

2011-01-01

Cemento-ossifying fibroma is a rare benign tumor most often discovered incidentally. A 72-year-old patient was referred for a subclinical lesion of the mandible. The orthopantomogram showed a well-circumscribed radiolucent osteolytic image, 1 cm in diameter, on the mandibular angle. On CT, the single lesion had a tissue aspect with a peripheral halo without enhancement after contrast injection. A cortical lacuna on the lingual side was noted. Surgical enucleation of the lesion was performed. The pathological examination confirmed the ossifying fibroma. Slow and progressive, cemento-ossifying fibroma is a rare benign tumor that reaches the maxilla and more frequently the mandible. The ossifying and cementifying fibromas are differentiated by their clinical, radiological, and histological findings. The authors discuss the pathogenesis and radiological signs guiding the choice of diagnostic and therapeutic methods. The treatment is surgical with an enucleation or wider resection with bone reconstruction for large fibromas. Copyright © 2010. Published by Elsevier Masson SAS.

Primary intraosseous Kaposi's sarcoma presenting as an asymptomatic periapical radiolucency: a case report.

PubMed

Noel, Kenson E; Mardirossian, George; Schneider, Lawrence

2007-05-01

Kaposi's sarcoma (KS) is a common mucocutaneous manifestation of acquired immunodeficiency syndrome (AIDS). Primary bone lesions have been reported but are rare. A 38-year-old African-American male who was human immunodeficiency virus (HIV)-positive appeared for the evaluation of an asymptomatic well-defined radiolucency of the mandibular midline discovered on routine radiographic examination. The adjacent central incisors were asymptomatic, nonmobile, and vital. The overlying mucosa and cortical plate were intact. Excision of the lesion revealed a fleshy, pink-red soft tissue mass with a uniform consistency. Histological examination showed a malignant spindle cell neoplasm containing numerous extravasated erythrocytes. The tumor cells exhibited positive immunohistochemical staining for CD31, CD34, and human herpesvirus 8. One year after surgical procedure, the surgical defect showed radiographic evidence of repair and there was no sign of recurrent tumor. This case represents the fourth reported instance of primary intraosseous involvement of the jaws with KS.

Sexual dimorphism of the internal mandibular chamber in Fayum Pliohyracidae (Mammalia)

USGS Publications Warehouse

de Blieux, D.D.; Baumrind, M.R.; Simons, E.L.; Chatrath, P.S.; Meyer, G.E.; Attia, Y.S.

2006-01-01

An internal mandibular fenestra and chamber are found in many fossil hyracoids. The internal mandibular fenestra is located on the lingual surface of the mandibular corpus and opens into a chamber within the mandible. The mandibular chamber is maximally developed in late Eocene Thyrohyrax meyeri and early Oligocene Thyrohyrax domorictus from the Fayum Province of Egypt. The function of this chamber is unknown as it is not found in extant hyraxes, nor is it known to occur in any other mammal. In Thyrohyrax, this feature appears to be sexually dimorphic because it is confined to roughly one half of the specimens that otherwise cannot be separated by dental characteristics or measurements. It has been suggested that the chamber is found in females based on the presumed distribution of this character in other fossil hyracoids. Fossils from Fayum Quarry L-41, preserving the sexually dimorphic anterior dentition, show that, in Thyrohyrax meyeri and Thyrohyrax domorictus, the internal mandibular chamber is found in males. In Thyrohyrax litholagus, an internal mandibular fenestra and inflated mandibular chamber occurs in males whereas females show the variable presence of an internal mandibular fossa or fenestra but lack an expanded chamber. Other genera show differing patterns of sexual variation in which some Fayum hyracoids have an internal mandibular fenestra in both sexes but with the greatest development of the mandibular chamber occurring in males. We review functions proposed for the internal mandibular chamber and suggest that it housed a laryngeal air sac that may have had a vocal function by acting as a resonating chamber. ?? 2006 by the Society of Vertebrate Paleontology.

[Temporo-mandibular joint. Morpho-functional considerations].

PubMed

Scutariu, M D; Indrei, Anca

2004-01-01

The temporo-mandibular joint is distinguished from most other synovial joints of the body by two features: 1. the two jointed components carry teeth whose position and occlusion introduce a very strong influence on the movements of the temporo-mandibular joint and 2. its articular surfaces are not covered by hyaline cartilage, but by a dense, fibrous tissue. This paper describes the parts of the temporo-mandibular joint: the articular surfaces (the condylar process of the mandible and the glenoid part of the temporal bone), the fibrocartilaginous disc which is interposed between the mandibular and the temporal surface, the fibrous capsule of the temporo-mandibular joint and the ligaments of this joint. All these parts present a very strong adaptation at the important functions of the temporo-mandibular joint.

[Clinical analysis of caries status of the mandibular second molar].

PubMed

You, Chun-an; Zheng, Ping; Hu, Ning; Su, Qin

2014-04-01

To collect the cases which have caries on the mandibular second molar and analyze the caries status and correlative factors. Patients treated in the Department of Endodontics in West China Hospital of Stomatology were randomly collected. The baseline information, primary sites and severity of dental caries on the mandibular second molar, and eruption pattern of the mandibular third molar were recorded. The data was analyzed with SPSS13.0 software package. Four hundred eighty-one patients including 227 males and 254 females were collected. Caries on the mandibular second molar starting from the occlusal, distal proximal and buccal surfaces accounted for 33.8%, 33.2% and 24.4%, respectively. Caries involving dental pulp (49.7%) were significantly more than deep and shallow to moderate caries (31.7% and 18.6%). Gender was not correlated with the site and severity of caries. However, impacted mandibular third molars and age were significantly related to both caries site and severity. Occlusal and distal proximal surfaces are the most predisposed sites to have caries on mandibular second molar. Impacted mandibular third molar and age are significantly related to caries of mandibular second molar.

Long Term Stability and Relapse Following Mandibular Advancement and Mandibular Setback Surgeries: A Cephalometric Study

PubMed Central

Darshan, S Vinay; Ronad, Yusuf Ahammed; Kishore, M S V; Shetty, K Sadashiva; Rajesh, M; Suman, S D

2014-01-01

Background: The aim was to evaluate the long-term hard and soft tissue changes following mandibular advancement and setback surgeries. Materials and Methods: A total of 16 subjects each were selected who underwent bilateral sagittal split osteotomy mandibular advancement and mandibular setback groups. Pre-surgical (T1), immediate post-surgical (T2) and long-term post-surgical (T3) cephalograms were compared for hard and soft tissue changes. After cephalometric measurements, the quantity of changes between T1-T2 and T1-T3 were determined for each patient. The mean difference between T1-T2 and T1-T3 was compared with assess the long-term changes and stability. Results: In mandibular advancement the mean difference between immediate post-surgical and long term post-surgical is 7%, which accounts for a relapse of 7%. In mandibular setback, the mean difference between immediate post-surgical and long-term post-surgical is 29%, which accounts for a relapse of 29%. Conclusion: Mandibular advancement remained stable over the long period when compared to mandibular setback. PMID:25395792

Long term stability and relapse following mandibular advancement and mandibular setback surgeries: a cephalometric study.

PubMed

Darshan, S Vinay; Ronad, Yusuf Ahammed; Kishore, M S V; Shetty, K Sadashiva; Rajesh, M; Suman, S D

2014-09-01

The aim was to evaluate the long-term hard and soft tissue changes following mandibular advancement and setback surgeries. A total of 16 subjects each were selected who underwent bilateral sagittal split osteotomy mandibular advancement and mandibular setback groups. Pre-surgical (T1), immediate post-surgical (T2) and long-term post-surgical (T3) cephalograms were compared for hard and soft tissue changes. After cephalometric measurements, the quantity of changes between T1-T2 and T1-T3 were determined for each patient. The mean difference between T1-T2 and T1-T3 was compared with assess the long-term changes and stability. In mandibular advancement the mean difference between immediate post-surgical and long term post-surgical is 7%, which accounts for a relapse of 7%. In mandibular setback, the mean difference between immediate post-surgical and long-term post-surgical is 29%, which accounts for a relapse of 29%. Mandibular advancement remained stable over the long period when compared to mandibular setback.

[EMG activities of the head, neck and upper trunk muscles with mandibular movements in healthy adults and mandibular asymmetry patients].

PubMed

Jiang, Ting; Zhang, Zhenkang; Yang, Zhaohui; Yi, Biao; Feng, Hailan; Wang, Xing

2002-03-25

To study the activities of head, neck and upper trunk muscles during mandibular movements in healthy adults and mandibular asymmetry patients. Electromyographic integrogram was used to record and analyze the electromyographic activities of the anterior temporal (Ta), posterior temporal (Tp), sternocleidomastoid (SCM), and trapezius (TRAP) muscles in rest position and during mandibular movement among 10 normal adults and 10 mandibular asymmetry patients. All the four muscles showed constant electromyographic activities when the mandible was in the rest position. The activities of Ta, Tp, and SCM muscles increased with protrusion of mandible, mouth opening, tapping, maximum clenching, and chewing. The activities of Ta and Tp muscles of the patients were 1.7 times greater than that of the normal adults during mandibular movement without occlusion, and were weaker by 50% during mandibular movement with occlusion. The difference between electromyographic activities during mandibular movement and in rest position was less among patients than among normal adults. The TRAP muscle of the patients showed constant electromyographic activities with the activity volume nearly 1.8 times that of the normal adults. The difference between the muscle and its namesake at the opposite side was greater among the patients (21%) than among the normal adults (8%). All the four muscles participate in the maintenance of rest position of mandible and the realization of mandibular movements. The coordination of muscular activities among mandibular asymmetry patients is poorer than that among normal adults.

Endodontic management of contralateral mandibular first molars with six root canals

PubMed Central

Bhargav, Kambhampati; Sirisha, Kantheti; Jyothi, Mandava; Boddeda, Mohan Rao

2017-01-01

The knowledge of variations in root canal morphology is essential for a successful endodontic outcome. Contralateral mandibular molar with six root canals is a rare entity. Root canal treatment of mandibular molars with aberrant canal configuration can be diagnostically and technically challenging. While dealing with variant mandibular molars, mishaps may happen. This case report describes variations in contralateral mandibular molars and also an endodontic mishap while managing them. PMID:29259369

Functional dissociation between action and perception of object shape in developmental visual object agnosia.

PubMed

Freud, Erez; Ganel, Tzvi; Avidan, Galia; Gilaie-Dotan, Sharon

2016-03-01

According to the two visual systems model, the cortical visual system is segregated into a ventral pathway mediating object recognition, and a dorsal pathway mediating visuomotor control. In the present study we examined whether the visual control of action could develop normally even when visual perceptual abilities are compromised from early childhood onward. Using his fingers, LG, an individual with a rare developmental visual object agnosia, manually estimated (perceptual condition) the width of blocks that varied in width and length (but not in overall size), or simply picked them up across their width (grasping condition). LG's perceptual sensitivity to target width was profoundly impaired in the manual estimation task compared to matched controls. In contrast, the sensitivity to object shape during grasping, as measured by maximum grip aperture (MGA), the time to reach the MGA, the reaction time and the total movement time were all normal in LG. Further analysis, however, revealed that LG's sensitivity to object shape during grasping emerged at a later time stage during the movement compared to controls. Taken together, these results demonstrate a dissociation between action and perception of object shape, and also point to a distinction between different stages of the grasping movement, namely planning versus online control. Moreover, the present study implies that visuomotor abilities can develop normally even when perceptual abilities developed in a profoundly impaired fashion. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Correlational Study of Scoliosis and Trunk Balance in Adult Patients with Mandibular Deviation

PubMed Central

Yang, Yang; Wang, Na; Wang, Wenyong; Ding, Yin; Sun, Shiyao

2013-01-01

Previous studies have confirmed that patients with mandibular deviation often have abnormal morphology of their cervical vertebrae. However, the relationship between mandibular deviation, scoliosis, and trunk balance has not been studied. Currently, mandibular deviation is usually treated as a single pathology, which leads to poor clinical efficiency. We investigated the relationship of spine coronal morphology and trunk balance in adult patients with mandibular deviation, and compared the finding to those in healthy volunteers. 35 adult patients with skeletal mandibular deviation and 10 healthy volunteers underwent anterior X-ray films of the head and posteroanterior X-ray films of the spine. Landmarks and lines were drawn and measured on these films. The axis distance method was used to measure the degree of scoliosis and the balance angle method was used to measure trunk balance. The relationship of mandibular deviation, spine coronal morphology and trunk balance was evaluated with the Pearson correlation method. The spine coronal morphology of patients with mandibular deviation demonstrated an “S” type curve, while a straight line parallel with the gravity line was found in the control group (significant difference, p<0.01). The trunk balance of patients with mandibular deviation was disturbed (imbalance angle >1°), while the control group had a normal trunk balance (imbalance angle <1°). There was a significant difference between the two groups (p<0.01). The degree of scoliosis and shoulder imbalance correlated with the degree of mandibular deviation, and presented a linear trend. The direction of mandibular deviation was the same as that of the lateral bending of thoracolumbar vertebrae, which was opposite to the direction of lateral bending of cervical vertebrae. Our study shows the degree of mandibular deviation has a high correlation with the degree of scoliosis and trunk imbalance, all the three deformities should be clinically evaluated in the management of mandibular deviation. PMID:23555836

Periodontal tissue reaction to customized nano-hydroxyapatite block scaffold in one-wall intrabony defect: a histologic study in dogs

PubMed Central

Lee, Jung-Seok; Park, Weon-Yeong; Cha, Jae-Kook; Jung, Ui-Won; Kim, Chang-Sung; Lee, Yong-Keun

2012-01-01

Purpose This study evaluated histologically the tissue responses to and the effects of a customized nano-hydroxyapatite (n-HA) block bone graft on periodontal regeneration in a one-wall periodontal-defect model. Methods A customized block bone for filling in the standardized periodontal defect was fabricated from prefabricated n-HA powders and a polymeric sponge. Bilateral 4×4×5 mm (buccolingual width×mesiodistal width×depth), one-wall, critical-size intrabony periodontal defects were surgically created at the mandibular second and fourth premolars of five Beagle dogs. In each dog, one defect was filled with block-type HA and the other served as a sham-surgery control. The animals were sacrificed following an 8-week healing interval for clinical and histological evaluations. Results Although the sites that received an n-HA block showed minimal bone formation, the n-HA block was maintained within the defect with its original hexahedral shape. In addition, only a limited inflammatory reaction was observed at sites that received an n-HA block, which might have been due to the high stability of the customized block bone. Conclusions In the limitation of this study, customized n-HA block could provide a space for periodontal tissue engineering, with minimal inflammation. PMID:22586523

Periodontal tissue reaction to customized nano-hydroxyapatite block scaffold in one-wall intrabony defect: a histologic study in dogs.

PubMed

Lee, Jung-Seok; Park, Weon-Yeong; Cha, Jae-Kook; Jung, Ui-Won; Kim, Chang-Sung; Lee, Yong-Keun; Choi, Seong-Ho

2012-04-01

This study evaluated histologically the tissue responses to and the effects of a customized nano-hydroxyapatite (n-HA) block bone graft on periodontal regeneration in a one-wall periodontal-defect model. A customized block bone for filling in the standardized periodontal defect was fabricated from prefabricated n-HA powders and a polymeric sponge. Bilateral 4×4×5 mm (buccolingual width×mesiodistal width×depth), one-wall, critical-size intrabony periodontal defects were surgically created at the mandibular second and fourth premolars of five Beagle dogs. In each dog, one defect was filled with block-type HA and the other served as a sham-surgery control. The animals were sacrificed following an 8-week healing interval for clinical and histological evaluations. Although the sites that received an n-HA block showed minimal bone formation, the n-HA block was maintained within the defect with its original hexahedral shape. In addition, only a limited inflammatory reaction was observed at sites that received an n-HA block, which might have been due to the high stability of the customized block bone. In the limitation of this study, customized n-HA block could provide a space for periodontal tissue engineering, with minimal inflammation.

Effect of root canal treatment procedures with a novel rotary nickel titanium instrument (TRUShape) on stress in mandibular molars: a comparative finite element analysis.

PubMed

Bonessio, Noemi; Arias, Ana; Lomiento, Guiseppe; Peters, Ove A

2017-01-01

The aim of this study was to investigate and compare, via finite element analysis (FEA), the effects of endodontic access and canal preparation on stress distribution under functional loading of a mandibular molar treated with novel (TRUShape) and conventional (Vortex) rotary root canal preparation instruments. Identical plastic mandibular molars with natural anatomy had all 4 canals shaped with either TRUShape or a conventional rotary, Vortex (#20 and #30, both by Dentsply Tulsa Dental). Finite element analysis was used to evaluate stress distribution in untreated and treated models. Micro-computed tomography (MCT) of the extracted teeth shaped in vitro was used to inform the FEA model regarding the geometry of root canals and external surfaces. Modeling the intact periodontal support and cancellous/cortical bone was based on anatomical data. Profiles of average and maximum von Mises stresses in dentin of the four treated conditions under functional loading were compared to the untreated model. This comparison was performed for each tooth model with and without root canal obturation and composite restoration. On average, the dentin sections with the most changes after preparation were located in the access cavity, with average stress increase up to +5.7, +8.5, +8.9, and +10.2 % for the TRUShape #20, Vortex #20, TRUShape #30 and Vortex #30, respectively, relative to the untreated model. Within the root canal system, the average stress differences were smaller than <5 % with lower values for TRUShape preparation. A reduction of the average stress in the access cavity was observed as an effect of the composite restoration, while about the same von Mises stress' profiles were found into the root canal. In this finite element analysis, preparation of the access cavity resulted in increased von Mises stresses under functional occlusal load. The limited (up to 0.7 %) retained radicular dentin in the TRUShape versus the Vortex cavity proved effective in reducing masticatory stresses. The bonded restoration modeled in this study only partially counterbalance the combined effects of access cavity and root canal preparation.

Superolateral dislocation of an intact mandibular condyle into the temporal fossa: case report and literature review.

PubMed

Sharma, Divashree; Khasgiwala, Ankit; Maheshwari, Bharat; Singh, Charanpreet; Shakya, Neelam

2017-02-01

Temporomandibular joint dislocation refers to the dislodgement of mandibular condyle from the glenoid fossa. Anterior and anteromedial dislocations of the mandibular condyle are frequently reported in the literature, but superolateral dislocation is a rare presentation. This report outlines a case of superolateral dislocation of an intact mandibular condyle that occurred in conjunction with an ipsilateral mandibular parasymphysis fracture. A review of the clinical features of superolateral dislocation of the mandibular condyle and the possible techniques of its reduction ranging from the most conservative means to extensive surgical interventions is presented. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Management of mandibular body fractures in pediatric patients: a case report with review of literature.

PubMed

John, Baby; John, Reena R; Stalin, A; Elango, Indumathi

2010-10-01

Mandibular fractures are relatively less frequent in children when compared to adults, which may be due to the child's protected anatomic features and infrequent exposure of children to alcohol related traffic accidents. Treatment principles of mandibular fractures differ from that of adults due to concerns regarding mandibular growth and development of dentition. A case of a 4.5-year-old boy with fractured body of mandible managed by closed reduction using open occlusal acrylic splint and circum mandibular wiring is presented. This article also provides a review of literature regarding the management of mandibular body fracture in young children.

Management of mandibular body fractures in pediatric patients: A case report with review of literature

PubMed Central

John, Baby; John, Reena R.; Stalin, A.; Elango, Indumathi

2010-01-01

Mandibular fractures are relatively less frequent in children when compared to adults, which may be due to the child's protected anatomic features and infrequent exposure of children to alcohol related traffic accidents. Treatment principles of mandibular fractures differ from that of adults due to concerns regarding mandibular growth and development of dentition. A case of a 4.5-year-old boy with fractured body of mandible managed by closed reduction using open occlusal acrylic splint and circum mandibular wiring is presented. This article also provides a review of literature regarding the management of mandibular body fracture in young children. PMID:22114443

Heritability of mandibular cephalometric variables in twins with completed craniofacial growth.

PubMed

Šidlauskas, Mantas; Šalomskienė, Loreta; Andriuškevičiūtė, Irena; Šidlauskienė, Monika; Labanauskas, Žygimantas; Vasiliauskas, Arūnas; Kupčinskas, Limas; Juzėnas, Simonas; Šidlauskas, Antanas

2016-10-01

To determine genetic and environmental impact on mandibular morphology using lateral cephalometric analysis of twins with completed mandibular growth and deoxyribonucleic acid (DNA) based zygosity determination. The 39 cephalometric variables of 141 same gender adult pair of twins were analysed. Zygosity was determined using 15 specific DNA markers and cervical vertebral maturation method was used to assess completion of the mandibular growth. A genetic analysis was performed using maximum likelihood genetic structural equation modelling (GSEM). The genetic heritability estimates of angular variables describing horizontal mandibular position in relationship to cranial base and maxilla were considerably higher than in those describing vertical position. The mandibular skeletal cephalometric variables also showed high heritability estimates with angular measurements being considerably higher than linear ones. Results of this study indicate that the angular measurements representing mandibular skeletal morphology (mandibular form) have greater genetic determination than the linear measurements (mandibular size). The shape and sagittal position of the mandible is under stronger genetic control, than is its size and vertical relationship to cranial base. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Soft tissue outcome after mandibular advancement--an anthropometric evaluation of 171 consecutive patients.

PubMed

Raschke, Gregor F; Rieger, Ulrich M; Bader, Rolf-Dieter; Guentsch, Arndt; Schaefer, Oliver; Schultze-Mosgau, Stefan

2013-06-01

There is an ongoing discussion in the literature about preoperative planning and postoperative evaluation of orthognathic surgery and its impact on facial appearance and aesthetics. We present an anthropometric and cephalometric evaluation of orthognathic surgery results based on reference anthropometric data. In 171 Class II patients, mandibular advancement by bilateral sagittal split osteotomy was performed. Preoperative as well as 3 and 9 months postoperative standardized frontal view and profile photographs and lateral cephalograms were evaluated in a standardized manner by use of 21 anthropometric indices. In cephalograms, SNA and SNB angle as well as Wits appraisal were investigated. Results of anthropometric and cephalometric measurements were correlated. Lower vermilion contour, vermilion and cutaneous total lower lip height, nose-lower face height, nose-face height, upper face-face height, upper lip- and chin-mandible height index showed significant pre- to postoperative changes as well as SNB angle and Wits appraisal. Furthermore, medial-lateral cutaneous upper lip height, vermilion and cutaneous total lower lip height and philtrum-mouth width index presented significant correlations to cephalometric measurements. The investigated anthropometric indices and cephalometric measurements presented reproducible results related to surgery. The correlation of cephalometric to anthropometric measurements has been proven useful for preoperative planning and postoperative evaluation of orthognathic surgery patients. The presented anthropometric measurements and their observed correlation to cephalometric measurements could lead to a better prediction and optimized planning of the soft tissue result in orthognathic surgery patients and thereby improve the aesthetic outcome.

Comparison of arch forms between Egyptian and North American white populations.

PubMed

Bayome, Mohamed; Sameshima, Glenn T; Kim, Yoonji; Nojima, Kunihiko; Baek, Seung-Hak; Kook, Yoon-Ah

2011-03-01

The aim of this study was to evaluate the morphologic differences in the mandibular arches of Egyptian and North American white subjects. The sample included 94 Egyptian subjects (35 Class I, 32 Class II, and 27 Class III) and 92 white subjects (37 Class I, 29 Class II, and 26 Class III). The subjects were grouped according to arch form types (tapered, ovoid, and square) to compare their frequency distribution between ethnic groups in each Angle classification. The most facial portions of 13 proximal contact areas were digitized on scanned images of mandibular casts to estimate the corresponding clinical bracket point for each tooth. Four linear and 2 proportional measurements were taken. In comparing arch dimensions, intermolar width was narrower in Egyptians than in the whites (P = 0.001). There was an even frequency distribution of the 3 arch forms in the Egyptian group. On the other hand, the most frequent arch form was ovoid followed by tapered and square in the white group; the square arch form was significantly less frequent than the tapered and ovoid arch forms (P = 0.029). The arch forms of Egyptians are narrower than those of whites. The distribution of the arch form types in Egyptians showed similar frequency, but the square arch form was less frequent in whites. It is recommended to select narrower archwires from the available variations to suit many Egyptian patients. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Reliability of mandibular canines as indicators for sexual dichotomy.

PubMed

Hosmani, Jagadish V; Nayak, Ramakant S; Kotrashetti, Vijayalakshmi S; S, Pradeep; Babji, Deepa

2013-02-01

Amongst the various calcified structures in the human body, teeth have gained lot of popularity in estimating the sex of an individual as they are highly resistant to destruction and decomposition. Using permanent mandibular canines many researchers have predicted a high level of accuracy in identifying the sex correctly. The purpose of our study was to gauge the effectiveness of mandibular canines in discerning sex. Fifty dental casts each of males and females were utilized for the study. Mesio-distal dimension and inter-canine distance of mandibular right and left canine was recorded using digital vernier caliper and mandibular canine index was calculated. The mean value of mesio-distal dimensions of right and left mandibular canine was slightly greater in males compared to females. The mandibular canine index was equal in both sexes. Inter-canine distance was marginally higher in males compared to females. Despite of higher values in males none of the parameters were statistically significant. The results herein bolster contemporary studies that mesio-distal dimensions of mandibular canines and mandibular canine index do not reflect sexual dimorphism and that its application should be discontinued in sex prediction among Indian populations. How to cite this article: Hosmani J V, Nayak R S, Kotrashetti V S, Pradeep S, Babji D. Reliability of Mandibular Canines as Indicators for Sexual Dichotomy. J Int Oral Health 2013; 5(1):1-7.

Long-Term Results of Mandibular Distraction Osteogenesis with a Resorbable Device in Infants with Robin Sequence: Effects on Developing Molars and Mandibular Growth.

PubMed

Paes, Emma C; Bittermann, Gerhard K P; Bittermann, Dirk; Muradin, Marvick M; van Hogezand, Rose; Etty, Erika; Mink van der Molen, Aebele B; Kon, Moshe; Breugem, Corstiaan C

2016-02-01

Mandibular distraction osteogenesis with a unidirectional resorbable device is an effective treatment option for severe upper airway obstruction in infants with Robin sequence. Long-term effects, especially with regard to tooth development and mandibular outgrowth, are not known. Robin sequence infants with a follow-up of greater than or equal to 5 years were included. Baseline characteristics were extracted from medical records. Panoramic and lateral cephalometric radiographs were analyzed and patients were recalled for physical examination. Ten infants underwent mandibular distraction osteogenesis at a mean age of 3.7 months (median, 19 months; range, 11 days to 27 months). Mean length of follow-up was 6.8 years (range, 5.0 to 7.9 years). Ten Robin sequence infants without mandibular distraction osteogenesis (mean length of follow-up, 7.4 years; range, 6.7 to 8.9 years) were the controls. Shape anomalies, positional changes, and root malformations of molars were seen significantly more often than in the control group (p = 0.007, p = 0.009, and p = 0.043, respectively). Mandibular length was shorter (p = 0.030), but mandibular ramus height was comparable (p = 0.838) with that of the non-mandibular distraction osteogenesis group. Compared with healthy controls, all Robin sequence infants had a significantly shorter mandible. Mandibular distraction osteogenesis with a resorbable system reveals overall good short- and long-term results, but the effects on developing molars and mandibular outgrowth likely necessitate secondary procedures. This factor should be considered when deciding on treatment options and counseling of parents. Therapeutic, III.

21 CFR 872.3960 - Mandibular condyle prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3960 Mandibular condyle prosthesis. (a) Identification. A mandibular condyle prosthesis is a device that is intended to be implanted in the human jaw to... requirement for premarket approval for any mandibular condyle prosthesis intended to be implanted in the human...

Cortical Bone Morphological and Trabecular Bone Microarchitectural Changes in the Mandible and Femoral Neck of Ovariectomized Rats

PubMed Central

Hsu, Pei-Yu; Tsai, Ming-Tzu; Wang, Shun-Ping; Chen, Ying-Ju; Wu, Jay; Hsu, Jui-Ting

2016-01-01

Objective This study used microcomputed tomography (micro-CT) to evaluate the effects of ovariectomy on the trabecular bone microarchitecture and cortical bone morphology in the femoral neck and mandible of female rats. Materials and Methods Twelve female Wister rats were divided into two groups: the control and ovariectomized groups. The rats in the ovariectomized group received ovariectomy at 8 weeks of age; all the rats were sacrificed at 20 weeks of age, and their mandibles and femurs were removed and scanned using micro-CT. Four microstructural trabecular bone parameters were measured for the region below the first mandibular molar and the femoral neck region: bone volume fraction (BV/TV), trabecular thickness (TbTh), trabecular separation (TbSp), and trabecular number (TbN). In addition, four cortical bone parameters were measured for the femoral neck region: total cross-sectional area (TtAr), cortical area (CtAr), cortical bone area fraction (CtAr/TtAr), and cortical thickness (CtTh). The CtTh at the masseteric ridge was used to assess the cortical bone morphology in the mandible. The trabecular bone microarchitecture and cortical bone morphology in the femoral necks and mandibles of the control group were compared with those of the ovariectomized group. Furthermore, Spearman’s correlation (rs) was conducted to analyze the correlation between the osteoporosis conditions of the mandible and femoral neck. Results Regarding the trabecular bone microarchitectural parameters, the BV/TV of the trabecular bone microarchitecture in the femoral necks of the control group (61.199±11.288%, median ± interquartile range) was significantly greater than that of the ovariectomized group (40.329±5.153%). Similarly, the BV/TV of the trabecular bone microarchitecture in the mandibles of the control group (51.704±6.253%) was significantly greater than that of the ovariectomized group (38.486±9.111%). Furthermore, the TbSp of the femoral necks in the ovariectomized group (0.185±0.066 mm) was significantly greater than that in the control group (0.130±0.026mm). Similarly, the TbSp of the mandibles in the ovariectomized group (0.322±0.047mm) was significantly greater than that in the control group (0.285±0.041mm). However, the TbTh and TbN trends for the mandibles and femoral necks were inconsistent between the control and ovariectomized groups. Regarding the cortical bone morphology parameters, the TtAr of the femoral necks in the ovariectomized group was significantly smaller than that in the control group. There was no significant difference in the TtAr, CtAr, or CtTh of the femoral necks between the control and ovariectomized groups, and no significant difference in the CtTh of the mandibles between the control and ovariectomized groups. Moreover, the BV/TV and TbSp of the mandibles were highly correlated with those of the femurs (rs = 0.874 and rs = 0.755 for BV/TV and TbSp, respectively). Nevertheless, the TbTh, TbN, and CtTh of the mandibles were not correlated with those of the femoral necks. Conclusion After the rats were ovariectomized, osteoporosis of the trabecular bone microarchitecture occurred in their femurs and mandibles; however, ovariectomy did not influence the cortical bone morphology. In addition, the parametric values of the trabecular bone microarchitecture in the femoral necks were highly correlated with those of the trabecular bone microarchitecture in the mandibles. PMID:27127909

Parafunctional loading and occlusal device on stress distribution around implants: A 3D finite element analysis.

PubMed

Borges Radaelli, Manuel Tomás; Idogava, Henrique Takashi; Spazzin, Aloisio Oro; Noritomi, Pedro Yoshito; Boscato, Noéli

2018-04-30

An occlusal device is frequently recommended for patients with bruxism to protect implant-supported restorations and prevent marginal bone loss. Scientific evidence to support this treatment is lacking. The purpose of this 3-dimensional (3D) finite element study was to evaluate the influence of an acrylic resin occlusal device, implant length, and insertion depth on stress distribution with functional and parafunctional loadings. Computer-aided design software was used to construct 8 models. The models were composed of a mandibular bone section including the second premolar and first and second molars. Insertion depths (bone level and 2 mm subcrestal) were simulated at the first molar. Three natural antagonist maxillary teeth and the placement or not of an occlusal device were simulated. Functional (200-N axial and 10-N oblique) and parafunctional (1000-N axial and 25-N oblique) forces were applied. Finite element analysis (FEA) was used to determine the maximum principal stress for the cortical and trabecular bone and von Mises for implant and prosthetic abutment. Stress concentration was observed at the abutment-implant and the implant-bone interfaces. Occlusal device placement changed the pattern of stress distribution and reduced stress levels from parafunctional loading in all structures, except in the trabecular bone. Implants with subcrestal insertion depths had reduced stress at the implant-abutment interface and cortical bone around the implant abutment, while the stress increased in the bone in contact with the implant. Parafunctional loading increased the stress levels in all structures when compared with functional loading. An occlusal device resulted in the lowest stress levels at the abutment and implant and the most favorable stress distribution between the cortical and trabecular bone. Under parafunctional loading, an occlusal device was more effective in reducing stress distribution for longer implants inserted at bone level. Subcrestally, implant insertion yielded the most favorable biomechanical conditions at the abutment-implant interface and at the coronal surface of the cortical bone, mainly when there was no occlusal device. Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Locally Produced BDNF Promotes Sclerotic Change in Alveolar Bone after Nerve Injury

PubMed Central

Ida-Yonemochi, Hiroko; Yamada, Yurie; Yoshikawa, Hiroyuki

2017-01-01

Brain-derived neurotrophic factor (BDNF), which is released due to nerve injury, is known to promote the natural healing of injured nerves. It is often observed that damage of mandibular canal induces local sclerotic changes in alveolar bone. We reported that peripheral nerve injury promotes the local production of BDNF; therefore, it was possible to hypothesize that peripheral nerve injury affects sclerotic changes in the alveolar bone. This study aimed to evaluate the effect of BDNF on osteogenesis using in vitro osteoblast-lineage cell culture and an in vivo rat osteotomy model. MC3T3-E1 cells were cultured with BDNF and were examined for cell proliferative activity, chemotaxis and mRNA expression levels of osteoblast differentiation markers. For in vivo study, inferior alveolar nerve (IAN) injury experiments and mandibular cortical osteotomy were performed using a rat model. In the osteotomy model, exogenous BDNF was applied to bone surfaces after corticotomy of the mandible, and we morphologically analyzed the new bone formation. As a result, mRNA expression of osteoblast differentiation marker, osteocalcin, was significantly increased by BDNF, although cell proliferation and migration were not affected. In the in vivo study, osteopontin-positive new bone formation was significantly accelerated in the BDNF-grafted groups, and active bone remodeling, involving trkB-positive osteoblasts and osteocytes, continued after 28 days. In conclusion, BDNF stimulated the differentiation of MC3T3-E1 cells and it promoted new bone formation and maturation. These results suggested that local BDNF produced by peripheral nerve injury contributes to accelerating sclerotic changes in the alveolar bone. PMID:28072837

Mechanical evaluation of the SLM fabricated, stiffness-matched, mandibular bone fixation plates

NASA Astrophysics Data System (ADS)

Jahadakbar, Ahmadreza; Shayesteh Moghaddam, Narges; Amerinatanzi, Amirhesam; Dean, David; Elahinia, Mohammad

2018-03-01

The standard of the care for the treatment of mandibular segmental defects is the use of Ti-6Al-4V bone fixation plates and screws to immobilize the grafted bone and the host mandible. While Ti-6Al-4V bone fixation plates provide strong immobilization during the healing period, they may disturb the stress distribution in the repaired mandible. The highly stiff Ti-6Al-4V fixation carries a great portion of the load which was previously borne by the mandible, and stress shielding may occur on the surrounding cortical bone. Based on the bone remodeling theory, stress shielding causes bone resorption in the effected region and may eventually lead to the failure of the surgical reconstruction. To address this issue, we have developed a new generation of the patient-specific, porous NiTi bone fixation plates which benefit from stiffness-matching of the adjacent bone. Using the CT scan data of the patient's defective mandible, the geometry for the required bone fixation plates is designed and the stiffness of the surrounding regions is measured. By introducing specific level and type of porosity to the bone fixation plate, its stiffness can be tuned. Finite Element simulations has verified the reduced level of stress shielding on the reconstructed mandible, in case of using the proposed bone fixation plates. Selective Lase Sintering has been used for fabrication of the porous NiTi bone fixation plates with six different levels of stiffness. Finite element simulations, and mechanical tests have been done to verify the performance of the fabricated parts resulting from our design and fabrication method.

Comparison of mandibular arch changes during alignment and leveling with 2 preadjusted edgewise appliances.

PubMed

Fleming, Padhraig S; DiBiase, Andrew T; Sarri, Grammati; Lee, Robert T

2009-09-01

Our objective was to compare the effects of 2 preadjusted appliances on angular and linear changes of the mandibular incisors, and transverse mandibular arch dimensional changes over a minimum of 30 weeks. This was a prospective, randomized, controlled, clinical trial a the Royal London Hospital, School of Dentistry, in London and the Kent and Canterbury Hospital in Canterbury, United Kingdom. Sixty- six consecutive patients satisfying the inclusion criteria were enrolled and randomly allocated to treatment with a self-ligating bracket system (SmartClip, 3M Unitek, Monrovia, Calif) and conventional preadjusted edgewise brackets (Victory, 3M Unitek). Initial study models and cephalograms were obtained within a month of starting the trial. All subjects received treatment with the following archwire sequence: 0.016-in round, 0.017 x 0.025-in rectangular, 0.019 x 0.025-in rectangular martensitic active nickel-titanium archwires, and 0.019 x 0.025-in stainless steel archwires. Final records, including study models and a lateral cephalogram, were collected a minimum of 30 weeks after initial appliance placement. Lateral cephalograms were assessed for treatment-related changes in mandibular incisor inclination and position. Transverse dimensional changes in intercanine, interpremolar, and intermolar dimensions, and the amount of crowding alleviated during the study period were assessed by comparison of pretreatment and posttreatment models. All measurements were made with a digital caliper (150 mm ISO 9001 electronic caliper, Tesa Technology, Renens, Switzerland). Sixty patients completed the study. After adjustment for pretreatment values, duration of treatment, and amount of crowding alleviated during the study period, bracket type had little effect on incisor inclination (P = 0.437) and positional changes (P = 0.35), and intercanine (P = 0.967), inter-first premolar (P = 0.495), and inter-second premolar (P = 0.905) dimensions. However, the self-ligating appliance produced slightly more expansion in the molar region, a difference that was statistically significant (P = 0.009). Pretreatment values for incisor inclination (P = 0.044) and transverse dimensions (P = 0.000) affected inclination and transverse changes, respectively, with proclination less likely when the labial segment was proclined at the outset and expansion unlikely during leveling and alignment in wider arches. Greater alleviation of crowding during the study period resulted in more incisor proclination (P = 0.000) and advancement (P = 0.000). There was little difference overall in the pattern of arch alignment and leveling related to the 2 preadjusted appliances. However, there was a statistically greater increase in intermolar width in the group treated with the self-ligating appliance, although the difference was only 0.91 mm.

Effect of mini-implant-supported mandibular overdentures on electromyographic activity of the masseter muscle during chewing of hard and soft food.

PubMed

Ashmawy, Tarek Mohy; El Talawy, Dina Bahgat; Shaheen, Nasser Hussein

2014-09-01

To objectively evaluate the effect of mini-implant- supported mandibular overdentures on electromyographic activity (EMG) of the masseter muscle during chewing of hard and soft foods. Twelve completely edentulous patients (4 females and 8 males) with maladaptive experience of wearing mandibular dentures received new maxillary and mandibular dentures. After 3 months of adaptation, four mini dental implants (MDIs) were inserted in the interforaminal region of the mandible, and the new mandibular dentures were connected to the implants immediately with O/ring attachments. The activity of masseter muscle (EMG) and the duration of chewing cycle were measured during chewing hard (carrot) and soft (gum) foods. The measurements were made 3 months after wearing each of the following prostheses: the new conventional dentures; and the MDI-retained mandibular overdentures. The EMG of masseter muscle increased and the DC decreased with MDI-retained mandibular overdentures when compared to conventional dentures. Hard food (carrot) was associated with increased EMG and decreased DC when compared to soft food (gum) for both conventional dentures and MDI-retained mandibular overdentures. Mini-implant-supported mandibular overdentures are associated with increased activity of masseter muscle and decreased duration of chewing cycle for both hard and soft foods when compared to conventional dentures.

A rare case of canine anomaly - a possible algorithm for treating it.

PubMed

Vaida, Ligia; Todor, Bianca Ioana; Corega, Claudia; Băciuţ, Mihaela; Băciuţ, Grigore

2014-01-01

Canine transmigration is a very rare dental anomaly in which an unerupted mandibular canine migrates, crossing the mandibular midline. This unusual condition is most often diagnosed by chance during a routine X-ray examination. The most common clinical signs announcing the presence of this anomaly are over-retention of the deciduous canine and the absence of permanent canine from the dental arch after its physiological period of eruption. In this paper, we present a clinical case, 10-year-old boy, who was diagnosed with mandibular right canine transmigration at three years after the start of orthodontic treatment, during which we were expecting the eruption of mandibular canines. The orthopantomograph revealed the mandibular right canine to be in a horizontal position under the apices of the incisors - type 2 transmigration pattern classified by Mupparapu (2002). Based on cone-beam computer tomography examination, we recommended a surgical exposure of the canine and orthodontic alignment. Due to the risk of root resorption of the mandibular right lateral incisor during orthodontic movement phase of canine transmigrated to the dental arch, we decided to align the mandibular right canine in a transposition, between the two mandibular right incisors. Then we resorted to adapting the mandibular right lateral incisor coronary morphology to simulate a canine and also to reshaping the canine coronary morphology to resemble a lateral incisor. This therapeutic approach allowed us to restore morphologically and functionally the mandibular dento-alveolar arch, preserving the entire dental system.

Thin-plate spline analysis of mandibular growth.

PubMed

Franchi, L; Baccetti, T; McNamara, J A

2001-04-01

The analysis of mandibular growth changes around the pubertal spurt in humans has several important implications for the diagnosis and orthopedic correction of skeletal disharmonies. The purpose of this study was to evaluate mandibular shape and size growth changes around the pubertal spurt in a longitudinal sample of subjects with normal occlusion by means of an appropriate morphometric technique (thin-plate spline analysis). Ten mandibular landmarks were identified on lateral cephalograms of 29 subjects at 6 different developmental phases. The 6 phases corresponded to 6 different maturational stages in cervical vertebrae during accelerative and decelerative phases of the pubertal growth curve of the mandible. Differences in shape between average mandibular configurations at the 6 developmental stages were visualized by means of thin-plate spline analysis and subjected to permutation test. Centroid size was used as the measure of the geometric size of each mandibular specimen. Differences in size at the 6 developmental phases were tested statistically. The results of graphical analysis indicated a statistically significant change in mandibular shape only for the growth interval from stage 3 to stage 4 in cervical vertebral maturation. Significant increases in centroid size were found at all developmental phases, with evidence of a prepubertal minimum and of a pubertal maximum. The existence of a pubertal peak in human mandibular growth, therefore, is confirmed by thin-plate spline analysis. Significant morphological changes in the mandible during the growth interval from stage 3 to stage 4 in cervical vertebral maturation may be described as an upward-forward direction of condylar growth determining an overall "shrinkage" of the mandibular configuration along the measurement of total mandibular length. This biological mechanism is particularly efficient in compensating for major increments in mandibular size at the adolescent spurt.

Mandibular marginal contouring in oriental aesthetic surgery: refined surgical concept and operative procedure.

PubMed

Satoh, Kaneshige; Mitsukawa, Nobuyuki

2014-05-01

In aesthetic mandibular contouring surgery, which is often conducted in Asians, the operative procedure is thought to deliver a more aesthetic mandibular shape by means of contouring conducted as a whole from the ramus to the symphysis. The authors describe the refined concept and operative procedures of mandibular marginal contouring. For the 7-year period from 2004 to 2011, mandibular marginal contouring has been used in 57 consecutive series of Japanese subjects. Patient ages ranged from 18 to 33 years, and the subjects included 15 men and 42 women. The surgery was carried out by cutting off the protruding deformed mandibular margin from the ramus to the symphysis. In 53 of 57 cases, the focus was on angle contouring. Concomitant genioplasty by horizontal osteotomy of the chin was conducted in 42 of 57 cases (recession, advancement, shortening, elongation, and correction of the shift variously). In 22 materials exhibiting bulk around the mandibular, the ramus to the body was excised sagittally and thinned. In all the patients, mandibular marginal contouring from the ramus to the symphysis was completed. Partial masseter muscle resection was conducted in 11 of 57 cases. Mandibular contouring effectively achieved a highly satisfactory result in all cases. The upper portion of the peripheral branch of the trunk of the mental nerve was dissected by an electric scalpel in 1 case but sutured immediately using an 8-0 nylon stitch. Transient palsy of the mental nerve was noticed in a few cases but subsided in 1 to 2 months. No particular complications were encountered. No secondary revision was required in this series. In mandibular angle plasty, mandibular marginal contouring from the ramus to the symphysis should be carried out by cutting off the angle keeping in mind the entire mandibular shape. This concept and the procedure can deliver greater patient satisfaction.

Screw fixation of the syndesmosis: a cadaver model comparing stainless steel and titanium screws and three and four cortical fixation.

PubMed

Beumer, Annechien; Campo, Martin M; Niesing, Ruud; Day, Judd; Kleinrensink, Gert-Jan; Swierstra, Bart A

2005-01-01

We assessed syndesmotic set screw strength and fixation capacity during cyclical testing in a cadaver model simulating protected weight bearing. Sixteen fresh frozen legs with artificial syndesmotic injuries and a syndesmotic set screw made of stainless steel or titanium, inserted through three or four cortices, were axially loaded with 800 N for 225,000 cycles in a materials testing machine. The 225,000 cycles equals the number of paces taken by a person walking in a below knee plaster during 9 weeks. Syndesmotic fixation failure was defined as: bone fracture, screw fatigue failure, screw pullout, and/or excessive syndesmotic widening. None of the 14 out of 16 successfully tested legs or screws failed. No difference was found in fixation of the syndesmosis when stainless steel screws were compared to titanium screws through three or four cortices. Mean lateral displacement found after testing was 1.05 mm (S.D. = 0.42). This increase in tibiofibular width exceeds values described in literature for the intact syndesmosis loaded with body weight. Based on this laboratory study it is concluded that the syndesmotic set screw cannot prevent excessive syndesmotic widening when loaded with a load comparable with body weight. Therefore, we advise that patients with a syndesmotic set screw in situ should not bear weight.

To Evaluate the Correlation Between Skeletal and Dental Parameters to the Amount of Crowding in Class II Div. 1 Malocclusions.

PubMed

Singh, Shivani; Shivaprakash, G

2017-09-01

Crowding of teeth is one of the most common problem that motivates the patient to seek orthodontic treatment. Determination of etiology of crowding could have a significant effect on treatment planning and prognosis of Class II malocclusion. Aim of this study was to evaluate the relationship of skeletal and dental parameters to amount of dental crowding in patients with Class II Divison 1 (div.1) malocclusion. Pretreatment lateral cephalograms and dental casts of 60 patients with skeletal Class II malocclusion were collected for the study. The sample was divided into two groups according to severity of pretreatment mandibular crowding. Group I consisted of cases with crowding ≥3 mm and Group II with crowding <3 mm. Lateral cephalograms for each patient was manually traced and skeletal parameters (effective maxillary and mandibular length, mandibular plane angle, Y Axis, lower anterior face height) and dental parameters (axial inclination of lower incisor, inclination of lower incisor to mandibular plane, interincisal angle) were measured. Unpaired t-test was used for intergroup comparison and relationship between different measurements was investigated using Pearson correlation coefficient. Among the skeletal parameters measured, only effective mandibular length exhibited statistically significant difference between the two groups. No statistically significant difference was found between the two groups for any of the dental parameters. Significant inverse correlation was found between mandibular crowding and effective mandibular length. Subjects with Class II div.1 malocclusion and moderate to severe mandibular crowding have significantly smaller effective mandibular base length than subjects with the same malocclusion and slight mandibular crowding.

A randomized clinical trial comparing mandibular incisor proclination produced by fixed labial appliances and clear aligners.

PubMed

Hennessy, Joe; Garvey, Thérèse; Al-Awadhi, Ebrahim A

2016-09-01

To compare the mandibular incisor proclination produced by fixed labial appliances and third generation clear aligners. Patients underwent a course of orthodontic treatment using either fixed labial appliances or clear aligners (Invisalign). Mandibular incisor proclination was measured by comparing pretreatment and near-end treatment lateral cephalograms. Eligibility criteria included adult patients with mild mandibular incisor crowding (<4 mm) and Class I skeletal bases (ANB, 1-4°). The main outcome was the cephalometric change in mandibular incisor inclination to the mandibular plane at the end of treatment. Eligible patients picking a sealed opaque envelope, which indicated their group allocation, was used to achieve randomization. Data was analyzed using a Welch two-sample t-test. Forty-four patients (mean age, 26.4 ± 7.7 years) were randomized in a 1:1 ratio to either the fixed labial appliance or the clear aligner group. Baseline characteristics were similar for both groups: Fixed appliance mean crowding was 2.1 ± 1.3 mm vs clear aligner mean crowding, 2.5 ± 1.3 mm; pretreatment mean mandibular incisor inclination for the fixed appliance group was 90.8 ± 5.4° vs 91.6 ± 6.4° for the clear aligner group. Fixed appliances produced 5.3 ± 4.3° of mandibular incisor proclination. Clear aligners proclined the mandibular incisors by 3.4 ± 3.2°. The difference between the two groups was not statistically significant (P > .05). There was no difference in the amount of mandibular incisor proclination produced by clear aligners and fixed labial appliances in mild crowding cases.

Association between third molar and mandibular angle fracture: A systematic review and meta-analysis.

PubMed

Giovacchini, Francesco; Paradiso, Daniele; Bensi, Caterina; Belli, Stefano; Lomurno, Giuseppe; Tullio, Antonio

2018-04-01

The aim of this study was to investigate the risk of mandibular angle fracture associated with the presence of a mandibular third molar and its position when the mandibular fracture occurs. A systematic literary search was performed in Pubmed, Scopus, and the Cochrane Library for observational studies with at least 250 patients that included frequency of mandibular angle fracture, presence of third molar, and its position. A total of seven studies were included in the review, from an initial search of 622 titles. The relative risk of mandibular angle fracture with third molar was 1.90 (95% CI = 1.47-2.46). The relative risk of mandibular angle fracture related to third molar position (according to the Pell and Gregory classification) was 1.18 (95% CI = 0.62-2.25), 1.98 (95% CI = 0.95-4.10), 2.72 (95% CI = 1.78-4.16), 1.31 (95% CI = 0.80-2.14), 2.21 (95% CI = 1.69-2.87) and 2.99 (95% CI = 2.12-4.22) for Class A, Class B, Class C, Class I, Class II, and Class III, respectively. Our meta-analysis reported a two-fold increased risk of mandibular angle fracture with the presence of a third molar in patients who presented with mandibular fractures. Even the third molar position seemed to influence mandibular angle fracture, especially Class C, Class II, and Class III. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Mandibular reconstruction using plates prebent to fit rapid prototyping 3-dimensional printing models ameliorates contour deformity.

PubMed

Azuma, Masaki; Yanagawa, Toru; Ishibashi-Kanno, Naomi; Uchida, Fumihiko; Ito, Takaaki; Yamagata, Kenji; Hasegawa, Shogo; Sasaki, Kaoru; Adachi, Koji; Tabuchi, Katsuhiko; Sekido, Mitsuru; Bukawa, Hiroki

2014-10-23

Recently, medical rapid prototyping (MRP) models, fabricated with computer-aided design and computer-aided manufacture (CAD/CAM) techniques, have been applied to reconstructive surgery in the treatment of head and neck cancers. Here, we tested the use of preoperatively manufactured reconstruction plates, which were produced using MRP models. The clinical efficacy and esthetic outcome of using these products in mandibular reconstruction was evaluated. A series of 28 patients with malignant oral tumors underwent unilateral segmental resection of the mandible and simultaneous mandibular reconstruction. Twelve patients were treated with prebent reconstruction plates that were molded to MRP mandibular models designed with CAD/CAM techniques and fabricated on a combined powder bed and inkjet head three-dimensional printer. The remaining 16 patients were treated using conventional reconstruction methods. The surgical and esthetic outcomes of the two groups were compared by imaging analysis using post-operative panoramic tomography. The mandibular symmetry in patients receiving the MRP-model-based prebent plates was significantly better than that in patients receiving conventional reconstructive surgery. Patients with head and neck cancer undergoing reconstructive surgery using a prebent reconstruction plate fabricated according to an MRP mandibular model showed improved mandibular contour compared to patients undergoing conventional mandibular reconstruction. Thus, use of this new technology for mandibular reconstruction results in an improved esthetic outcome with the potential for improved quality of life for patients.

Effect of removable functional appliances on mandibular length in patients with class II with retrognathism: systematic review and meta-analysis.

PubMed

Santamaría-Villegas, Adriana; Manrique-Hernandez, Rubén; Alvarez-Varela, Emery; Restrepo-Serna, Claudia

2017-02-01

Orthopedic functional devices, are used to improve mandibular length in skeletal class II patients. However, the orthopedic functional device with the best effect to increasing the mandibular length, has not been identified before. Thus, the aim of the present investigation was to evaluate Randomized Controlled Trials (RCT), to determine the best functional appliance improving mandibular length in subjects with retrognathism. A systematic review and meta-analysis was performed, including studies published and indexed in databases between 1966 and 2016. RCTs evaluating functional appliances' effects on mandibular length (Condilion-Gnation (Co-Gn) and Condilion-Pogonion (Co-Po)), were included. Reports' structure was evaluated according to 2010 CONSORT guide. The outcome measure was distance between Co-Gn and/or Co-Po after treatment. Data were analyzed with Cochran Q Test and random effects model. Five studies were included in the meta-analysis. The overall difference in mandibular length was 1.53 mm (Confidence Interval (CI) 95% 1.15-1.92) in comparison to non-treated group. The Sander Bite Jumping reported the greatest increase in mandibular length (3.40 mm; CI 95% 1.69-5.11), followed by Twin Block, Bionator, Harvold Activator and Frankel devices. All removable functional appliances, aiming to increase mandibular length, are useful. Sander Bite Jumping was observed to be the most effective device to improve the mandibular length.

Human mandibular shape is associated with masticatory muscle force.

PubMed

Sella-Tunis, Tanya; Pokhojaev, Ariel; Sarig, Rachel; O'Higgins, Paul; May, Hila

2018-04-16

Understanding how and to what extent forces applied to the mandible by the masticatory muscles influence its form, is of considerable importance from clinical, anthropological and evolutionary perspectives. This study investigates these questions. Head CT scans of 382 adults were utilized to measure masseter and temporalis muscle cross-sectional areas (CSA) as a surrogate for muscle force, and 17 mandibular anthropometric measurements. Sixty-two mandibles of young individuals (20-40 years) whose scans were without artefacts (e.g., due to tooth filling) were segmented and landmarked for geometric morphometric analysis. The association between shape and muscle CSA (controlled for size) was assessed using two-block partial least squares analysis. Correlations were computed between mandibular variables and muscle CSAs (all controlled for size). A significant association was found between mandibular shape and muscle CSAs, i.e. larger CSAs are associated with a wider more trapezoidal ramus, more massive coronoid, more rectangular body and a more curved basal arch. Linear measurements yielded low correlations with muscle CSAs. In conclusion, this study demonstrates an association between mandibular muscle force and mandibular shape, which is not as readily identified from linear measurements. Retrodiction of masticatory muscle force and so of mandibular loading is therefore best based on overall mandibular shape.

A patient with mandibular deviation and 3 mandibular incisors treated with asymmetrically bent improved superelastic nickel-titanium alloy wires.

PubMed

Ikeda, Yuhei; Kokai, Satoshi; Ono, Takashi

2018-01-01

Skeletal and dental discrepancies cause asymmetric malocclusions in orthodontic patients. It is difficult to achieve adequate functional occlusion and guidance in patients with congenital absence of a mandibular incisor due to the tooth-size discrepancy. Here, we describe the orthodontic treatment of a 22-year-old woman with an asymmetric Angle Class II malocclusion, mandibular deviation to the left, and 3 mandibular incisors. The anterior teeth and maxillary canines were crowded. We used an improved superelastic nickel-titanium alloy wire (Tomy International, Tokyo, Japan) to compensate for the asymmetric mandibular arch and an asymmetrically bent archwire to move the maxillary molars distally. A skeletal anchorage system provided traction for intermaxillary elastics, and extractions were not needed. We alleviated the crowding and created an ideal occlusion with proper overjet, overbite, and anterior guidance with Class I canine and molar relationships. This method of treatment with an asymmetrically bent nickel-titanium alloy wire provided proper Class I occlusion and anterior guidance despite the mandibular deviation to the left and 3 mandibular incisors, without the need for extractions. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Backward distraction osteogenesis in a patient with severe mandibular micrognathia.

PubMed

Mitsukawa, Nobuyuki; Morishita, Tadashi; Saiga, Atsuomi; Akita, Shinsuke; Kubota, Yoshitaka; Satoh, Kaneshige

2013-09-01

Maxillary skeletal prognathism can involve severe mandibular micrognathia with marked mandibular retrognathism or hypoplasia. For patients with such a condition, a conventional treatment is mandibular advancement by sagittal split ramus osteotomy (SSRO). This procedure has problems such as insufficient advancement, instability of jaw position, and postoperative relapse. Thus, in recent years, mandibular distraction osteogenesis has been used in some patients. Mandibular distraction has many advantages, but an ideal occlusion is difficult to achieve using this procedure. That is, 3-dimensional control cannot be attained using an internal device that is unidirectional. This report describes a case of severe mandibular micrognathia in a 14-year-old girl treated using backward distraction osteogenesis. This procedure was first reported by Ishii et al (Jpn J Jaw Deform 2004; 14:49) and involves a combination of SSRO and ramus distraction osteogenesis. In the present study, intermaxillary fixation in centric occlusion was performed after osteotomy, and proximal bone segments were distracted in a posterosuperior direction. This procedure is a superior surgical technique that avoids the drawbacks of SSRO and conventional mandibular distraction. However, it applies a large load to the temporomandibular joints and requires thorough management. Thus, careful evaluation needs to be made of the indication for backward distraction osteogenesis.

Management of Broken Dental Implant Abutment in a Patient with Bruxism: A Rare Case Report and Review of Literature.

PubMed

Al-Almaie, Saad

2017-01-01

This rare case report describes prosthodontic complications resulting from a dental implant was placed surgically more distally in the area of the missing mandibular first molar with a cantilever effect and a crest width of >12 mm in a 59-year-old patient who had a history of bruxism. Fracture of abutment is a common complication in implant was placed in area with high occlusal forces. Inability to remove the broken abutment may most often end up in discarding the implant. Adding one more dental implant mesially to the previously placed implant, improvisation of technique to remove the broken abutment without sacrificing the osseointegrated dental implant, fabrication with cemented custom-made abutment to replace the broken abutment for the first implant, and the use of the two implants to replace a single molar restoration proved reliable and logical treatment solutions to avoid these prosthodontic complications.

Retrospective Study of Root Canal Configurations of Mandibular Third Molars Using CBCT- Part-II.

PubMed

Somasundaram, Pavithra; Rawtiya, Manjusha; Wadhwani, Shefali; Uthappa, Roshan; Shivagange, Vinay; Khan, Sheeba

2017-06-01

Abnormal root canal morphologies of third molars can be diagnostically and technically challenging during root canal treatment. The aim of this retrospective study was to investigate the root and canal morphology of mandibular third molars in Central India population by using Cone Beam Computed Tomography (CBCT) analysis. CBCT images of 171 mandibular third molars were observed and data regarding number of roots, number of canals, Vertucci's classification in each root, prevalence of C shaped canal, gender and topographical relation of morphology in mandibular third molar was statistically evaluated. Majority of mandibular third molars had two roots (84.2%) and three canals (64.3%). Most mesial root had Vertucci Type II (55.6%) and Vertucci Type IV (22.2%), distal root had Type I canals (87.5%). Over all prevalence of C shaped canals in mandibular third molars was 9.4%. There was a high prevalence of two rooted mandibular third molars with three canals.

[Mandibular-driven simultaneous maxillo-mandibular distraction for hemifacial microsomia with rapid prototyping technology].

PubMed

Gao, Quan-Wen; Song, Hui-Feng; Xu, Ming-Huo; Liu, Chun-Ming; Chai, Jia-Ke

2013-11-01

To explore the clinical application of mandibular-driven simultaneous maxillo-mandihular distraction to correct hemifacial microsomia with rapid prototyping technology. The patient' s skull resin model was manufactured with rapid prototyping technology. The osteotomy was designed on skull resin model. According to the preoperative design, the patients underwent Le Fort I osteotomy and mandibular ramus osteotomy. The internal mandible distractor was embedded onto the osteotomy position. The occlusal titanium pin was implanted. Distraction were carried out by mandibular-driven simultaneous maxillo-mandihular distraction 5 days after operation. The distraction in five patients was complete as designed. No infection and dysosteogenesis happened. The longest distance of distraction was 28 mm, and the shortest distance was 16 mm. The facial asymmetry deformity was significantly improved at the end of distraction. The ocelusal plane of patients obviously improved. Rapid prototyping technology is helpful to design precisely osteotomy before operation. Mandibular-driven simultaneous maxillo-mandibular distraction can correct hemifacial microsomia. It is worth to clinical application.

Elders with implant overdentures: a 22-year clinical report.

PubMed

Alsabeeha, Nabeel H M

2012-09-01

To report on the long-term survival and prosthodontic maintenance of two edentulous adults with mandibular overdentures supported by hydroxyapatite (HA)-coated implants. Mandibular implant overdentures are a successful treatment option with positive impact on the quality of life of elderly edentulous adults. Long-term survival of the implants requires continued rigorous prosthodontic maintenance. Two elderly edentulous adults with mandibular overdentures supported by 2 HA-coated implants were presented for prosthodontic rehabilitation after 22 years of placement. The implants were osseo-integrated and surviving at presentation based on accepted criteria. The mandibular implant overdentures suffered recurrent loss of retention and stability. Prosthodontic treatment involving the replacement of defective attachment systems and construction of new sets of mandibular implant overdentures opposing complete maxillary dentures is presented. The long-term survival of mandibular 2-implant overdentures requires continued prosthodontic maintenance. A conservative approach in the rehabilitation of two older edentulous adults with mandibular 2-implant overdentures was described including proper selection of attachment systems. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

Retrospective Study of Root Canal Configurations of Mandibular Third Molars Using CBCT- Part-II

PubMed Central

Somasundaram, Pavithra; Wadhwani, Shefali; Uthappa, Roshan; Shivagange, Vinay; Khan, Sheeba

2017-01-01

Introduction Abnormal root canal morphologies of third molars can be diagnostically and technically challenging during root canal treatment. Aim The aim of this retrospective study was to investigate the root and canal morphology of mandibular third molars in Central India population by using Cone Beam Computed Tomography (CBCT) analysis. Materials and Methods CBCT images of 171 mandibular third molars were observed and data regarding number of roots, number of canals, Vertucci’s classification in each root, prevalence of C shaped canal, gender and topographical relation of morphology in mandibular third molar was statistically evaluated. Results Majority of mandibular third molars had two roots (84.2%) and three canals (64.3%). Most mesial root had Vertucci Type II (55.6%) and Vertucci Type IV (22.2%), distal root had Type I canals (87.5%). Over all prevalence of C shaped canals in mandibular third molars was 9.4%. Conclusion There was a high prevalence of two rooted mandibular third molars with three canals. PMID:28764294

X-cephalometric study of different parts of the upper airway space and changes in hyoid position following mandibular fractures.

PubMed

Chen, L-J; Zhao, M-C; Pan, X-F; Wei, Y-Q; Wang, D-Y

2013-09-01

This study analyses the different parts of the upper airway space and the changes in hyoid position. The results provide a clinical reference for developing timely and effective treatment programmes for patients with mandibular fractures caused by maxillofacial trauma. Standard X-cephalometric measurements of the lateral skull of 210 subjects were taken. The subjects were divided into four fracture groups: condylar, mandibular angle, mandibular body, and parasymphyseal. The radiographs of the mandibular fracture groups were compared with the normal occlusion group to analyse the upper airway space and the changes in hyoid position. Different types of fractures have different effects on the upper airway space. Bilateral mandibular body fracture and the parasymphyseal fracture have a significant influence on the lower oropharyngeal and laryngopharyngeal airway spaces, with serious obstructions severely restricting the ventilatory function of patients. Fractures at different parts of the mandibular structure are closely related to the upper airway and hyoid position.

[Morphological analysis of alveolar bone of anterior mandible in high-angle skeletal class II and class III malocclusions assessed with cone-beam computed tomography].

PubMed

Ma, J; Jiang, J H

2018-02-18

To evaluate the difference of features of alveolar bone support under lower anterior teeth between high-angle adults with skeletal class II malocclusions and high-angle adults presenting skeletal class III malocclusions by using cone-beam computed tomography (CBCT). Patients who had taken the images of CBCT were selected from the Peking University School and Hospital of Stomatology between October 2015 and August 2017. The CBCT archives from 62 high-angle adult cases without orthodontic treatment were divided into two groups based on their sagittal jaw relationships: skeletal class II and skeletal class III. vertical bone level (VBL), alveolar bone area (ABA), and the width of alveolar bone were measured respectively at the 2 mm, 4 mm, 6 mm below the cemento-enamel junction (CEJ) level and at the apical level. After that, independent samples t-tests were conducted for statistical comparisons. The ABA of the mandibular alveolar bone in the area of lower anterior teeth was significantly thinner in the patients of skeletal class III than those of skeletal class II, especially in terms of the apical ABA, total ABA on the labial and lingual sides and the ABA at 6 mm below CEJ level on the lingual side (P<0.05). The thickness of the alveolar bone of mandibular anterior teeth was significantly thinner in the subjects of skeletal class III than those of skeletal class II, especially regarding the apical level on the labial and lingual side and at the level of 4 mm, 6 mm below CEJ level on the lingual side (P<0.05). The ABA and the thickness of the alveolar bone of mandibular anterior teeth were significantly thinner in the group of skeletal class III adult patients with high-angle when compared with the sample of high-angle skeletal class II adult cases. We recommend orthodontists to be more cautious in treatment of high-angle skeletal class III patients, especially pay attention to control the torque of lower anterior teeth during forward and backward movement, in case that the apical root might be absorbed or fenestration happen in the area of lower anterior teeth.

[Inferior hemiarthroplasty of the temporo-mandibular joint with articulated condylar prosthesis type Stryker].

PubMed

Bucur, A; Dincă, O; Totan, C; Ghită, V

2007-01-01

The optimal reconstruction of the mandible and of the temporo-mandibular joint after mandibular hemi-resection with disarticulation is still controversial in literature. This paperwork presents our experience on four cases in the reconstruction of the mandible together with the inferior arthroplasty of the temporo-mandibular joint, after the resection of extended benign tumors of the mandible, based on fibular free vascularized grafts having attached a Stryker titanium condylar prosthesis reconstructing the inferior segment of the temporo-mandibular joint. Our results for the this technique were excellent, with a functional rehabilitation very close to normal. After reviewing the various techniques and their arguments in literature, with accent on the TMJ reconstruction, we consider this method to be optimal for the reconstruction of mandibular defects in patients with neoplastic conditions.

Aplasia of the mandibular condyle associated with some orthopaedic abnormalities

PubMed Central

Canger, E M; Çelenk, P

2012-01-01

A rare case of aplasia of mandibular condyle associated with some other orthopaedic problems is presented. A 5-year-old boy attended our clinic with a chief complaint of facial asymmetry and chewing difficulty. The mandible was deviated to the left. The occlusion also showed a deflection to the left of the mandibular midline. He also had walking difficulty owing to a hip abnormality. Panoramic radiographic examination of the patient revealed that the left mandibular condyl was totally absent. The right condyle was unremarkable. His history revealed neither trauma nor any significant disease. Aplasia is a rare anomaly and means the insufficient development of the mandibular condyle. True agnesis of the mandibular condyle is extremely rare. Association of the manifestations of the patient with some orthopaedic problems makes this case interesting. PMID:22116127

An Assessment of Curve of Spee in Healthy Human Permanent Dentitions: A Cross Sectional Analytical Study in a Group of Young Indian Population.

PubMed

Krishnamurthy, Sushma; Hallikerimath, Rajendra B; Mandroli, Praveenkumar S

2017-01-01

An awareness of the standard value of the maxillary and the mandibular curves of Spee may aid the clinician in developing occlusion in the sagittal plane and would be useful when providing prosthetic rehabilitation for patients with occlusal derangement. To assess and compare the radius and depth of curve of Spee in maxillary and mandibular arches in men and women, in a group of young Indian population. The study cohort consisted of 25 men and 25 women between 19 to 24 years. Impression of maxillary and mandibular arches were made with alginate. Casts were poured in die stone. Standardized digital pictures of the right side of maxillary and mandibular dental casts were made with a digital camera and transferred to a computer. Tips of the distal cusps of molars, premolars and canines of the maxilla and mandible were located. The radius and the depth of the curve of Spee were measured from the digital photographs of dental casts, with the help of 'dimension tool' in the computer software (Corel DRAW X5). Mann-Whitney test was used to analyze the difference in the curve of Spee between men and women and the difference between maxillary and mandibular arches. The mean values were as follows: a) Men: Radii of curve of Spee in the maxillary and mandibular arch were 140.22±65.98 and 109.67±46.80 respectively; depths of curve of Spee in maxillary and mandibular arch were 1.65±0.67 and 1.49±0.74 respectively; b) Women: Radii of curve of Spee in the maxillary and mandibular arch were 120.58±63.91 and 98.31±63.59 respectively; depths of curve of Spee in maxillary and mandibular arch were 1.45±0.54 and 1.40±0.61 respectively. In the mandibular arch, the difference in the radii (p=0.0467) was statistically significant between men and women. In women, the difference in radii (p=0.0467) between maxillary and mandibular arches was statistically significant. The radii and depths of curve of Spee were larger in maxillary than mandibular arches in both men and women. Also, the difference in the radii of mandibular arch was statistically significant between men and women.

The sonar aperture and its neural representation in bats.

PubMed

Heinrich, Melina; Warmbold, Alexander; Hoffmann, Susanne; Firzlaff, Uwe; Wiegrebe, Lutz

2011-10-26

As opposed to visual imaging, biosonar imaging of spatial object properties represents a challenge for the auditory system because its sensory epithelium is not arranged along space axes. For echolocating bats, object width is encoded by the amplitude of its echo (echo intensity) but also by the naturally covarying spread of angles of incidence from which the echoes impinge on the bat's ears (sonar aperture). It is unclear whether bats use the echo intensity and/or the sonar aperture to estimate an object's width. We addressed this question in a combined psychophysical and electrophysiological approach. In three virtual-object playback experiments, bats of the species Phyllostomus discolor had to discriminate simple reflections of their own echolocation calls differing in echo intensity, sonar aperture, or both. Discrimination performance for objects with physically correct covariation of sonar aperture and echo intensity ("object width") did not differ from discrimination performances when only the sonar aperture was varied. Thus, the bats were able to detect changes in object width in the absence of intensity cues. The psychophysical results are reflected in the responses of a population of units in the auditory midbrain and cortex that responded strongest to echoes from objects with a specific sonar aperture, regardless of variations in echo intensity. Neurometric functions obtained from cortical units encoding the sonar aperture are sufficient to explain the behavioral performance of the bats. These current data show that the sonar aperture is a behaviorally relevant and reliably encoded cue for object size in bat sonar.

An overlay partial denture to restore worn mandibular anterior teeth.

PubMed

Samant, Asha; DeSciscio, Peter

2014-01-01

Restoring worn anterior mandibular teeth is a challenge, especially when teeth are small, esthetics are a concern, the long-term prognosis is questionable, and/or patient finances are an issue. This article describes an alternate treatment for a patient with a collapsed bite, missing posterior mandibular teeth, an ill-fitting complete maxillary denture with poor esthetics, and irregular, worn mandibular anterior teeth.

Clinical and radiological investigations of mandibular overdentures supported by conventional or mini-dental implants: A 2-year prospective follow-up study.

PubMed

Temizel, Sonay; Heinemann, Friedhelm; Dirk, Cornelius; Bourauel, Christoph; Hasan, Istabrak

2017-02-01

Conventional dental implants are not applicable in the mandibular interforaminal region if bone volume is limited. Mini-dental implants offer an alternative means of supporting mandibular overdentures in a narrow residual ridge, without additional surgery. The purpose of this nonrandomized clinical trial was to compare the ability of mini-dental implants with that of conventional dental implants in supporting mandibular overdentures during a 2-year clinical follow-up. Bone quality, bone resorption, implant stability, and oral health were assessed radiographically. A total of 32 participants with edentulism were included. Twenty-two participants (99 implants) received 4 to 5 mini-dental implants (diameter: 1.8-2.4 mm; length: 13-15 mm, study group), and 10 participants (35 implants) received 2 to 4 conventional dental implants (diameter: 3.3-3.7 mm; length: 11-13 mm, control group). The selection of the participants in the study or control group was based on the available bone volume in the mandible. The selection was not randomized. The density of cortical bone thickness was measured in Hounsfield units (HU) from computed tomography data, and patients were followed for 2 years. The participants were examined 3, 6, 12, and 24 months after surgery. Primary stability immediately after the insertion of dental implants (Periotest), secondary stability 6 months after implantation, modified plaque, bleeding on probing indices, and probing depth were measured and analyzed statistically (α=.05). The mean HU value 6 months after implantation in the participants who received mini-dental implants was significantly (P=.035) higher (1250 HU) than that in the participants who received conventional dental implants (1100 HU). The probing depths around the conventional dental implants (1.6 and 1.8 mm, respectively) were significantly higher than those around the mini-dental implants (1.3 and 1.2 mm, respectively) 12 and 24 months after surgery, respectively (P<.001). The mean primary and secondary stability values for conventional dental implants were -4.0 and -4.9, respectively. The primary and secondary stability values for the mini-dental implants were -0.3 and -1.4, respectively. The Periotest values of the primary (measured immediately after implant insertion) and secondary implant stabilities (measured 6 months after implant insertion) were significantly higher for the conventional dental implants than for the mini-dental implants (P<.001). Based on this 2-year clinical trial, patients receiving mini-dental implants had clinical outcomes similar to those of patients receiving conventional dental implants to support overdenture prostheses. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Relationship between fracture of mandibular condyle and absence of unerupted mandibular third molar-a retrospective study.

PubMed

Rajan, Ritesh; Verma, Dinesh Kumar; Borle, R M; Yadav, Abhilasha

2016-06-01

The purpose of the present study was to find, if there exists, a co-relation between presence of unerupted mandibular third molar and fracture of mandibular condyle. A retrospective, multicenter study was done collecting the data of all mandibular condyle fractures treated from November 2006 till August 2015. Data was collected from the patient's records and radiographs for the following information: age, sex, etiology of fracture, presence and state of lower third molars, and associated fracture. The results were subjected to statistical analysis. Out of 180 patients of condylar fracture, unerupted third molars were present in 35 (19.44 %) cases compared to 145 (80.55 %) cases of condylar fracture where the unerupted third molars were not present. The difference was statistically significant (p < 0.05). In the unerupted third molar present group, isolated bilateral condylar fracture was seen in 4 (11.4 %) cases, bilateral condylar fracture associated with other mandibular fractures in 9 (25.7 %) cases, isolated unilateral condylar fracture in 0 (0.0 %) cases, and unilateral condylar fracture associated with other mandibular fractures in 17 (48.5 %) cases and condylar fracture associated with mid face fractures in 5 (14.2 %) cases. In the unerupted third molar absent group, isolated bilateral condylar fracture was seen in 5 (3.4 %) cases, bilateral condylar fracture associated with other mandibular fractures in 30 (20.6 %) cases, isolated unilateral condylar fracture in 24 (16.5 %) cases, unilateral condylar fracture associated with other mandibular fractures in 73 (50.34 %) cases, and condylar fracture associated with mid face fractures in 13(8.96 %) cases. The difference between the groups was statistically significant (p = 0.032). This study suggests that the fractures of mandibular condylar region have a significantly higher incidence in patients without an unerupted mandibular third molar.

Epidemiology of Surgically Managed Mandibular Condylar Fractures at a Tertiary Referral Hospital in Urban Southwest China.

PubMed

Thapa, Swosti; Wang, Jun; Hu, Hong-Tao; Zhang, Fu-Gui; Ji, Ping

2017-01-01

Mandibular condylar fracture is one of the commonest maxillofacial fractures treated by maxillofacial surgeons. Demography of the patients, causation, and characteristics of the fracture depends on various socio-economic factors. Hence, maxillofacial surgeons should be familiar with epidemiology of mandibular condylar fracture. This study retrospectively describes the demography, etiology, fracture characteristics, and hospital utilization of surgically treated mandibular condylar fractures in a tertiary referral hospital in urban China in past five years. Data of all patients who underwent surgical management between 2011 and 2015 were collected. This included aetiology, characteristics of fracture, time, age, sex, associated injuries, and hospital utilization of 166 patients with 208 mandibular condylar fractures. These patients had undergone open reduction and internal fixation with either miniplates or lag screws. Among the fracture of head of mandibular condyle, 21.28% of the patients had the fracture segments removed. These data were statistically analyzed to describe the epidemiology of mandibular condylar fracture. Most of the patients had unilateral mandibular condylar fractures (74.7%). Male patients (76.51%) outnumbered female patients (23.49%) in this cohort. The average age of the patients was 37 years. The fractures were mostly caused by fall from height (60.84%) and were located at the condylar neck (53.61%). Most of the patients had other associated maxillofacial injuries (71.08%) which were mostly located at symphysis and parasymphysis (44.59%). It took 12.58 +/- 0.35 days of hospitalization for the treatment. Fall from height was the most prevalent cause of mandibular condylar injury in mountainous urban China. The people at highest risk were middle-aged men. Mandibular condylar fracture was mostly located at the condylar neck and was usually associated with fracture at the symphysis and parasymphysis.

TMD symptoms and vertical mandibular symmetry in young adult orthodontic patients in North Sumatra, Indonesia: a cross-sectional study

PubMed Central

Sofyanti, Ervina; Boel, Trelia; Soegiharto, Benny; Auerkari, Elza I.

2018-01-01

Background: Temporomandibular joint disorder (TMD) includes symptoms of pain and dysfunction in the muscles of mastication and the temporomandibular joint. Differences in vertical condylar height, observed in the assessment of mandibular asymmetry, is a structural alteration that represents a risk factor for TMD. The study aimed to evaluate the association between TMD symptoms and vertical mandibular symmetry in young adult orthodontic patients in North Sumatra, Indonesia.  Methods: The cross-sectional study included 18-25-year-old (mean ± SD, 21.9 ± 2.0 years) old orthodontic patients admitted to the Dental Hospital of Universitas Sumatera Utara, Medan, between June 2016 and March 2017. Vertical mandibular asymmetry was assessed from all 106 subjects using Kjellberg’s technique from pre-treatment panoramic radiographs. The TMD symptoms were assessed by structural interviews using modified questionnaires based on Temporomandibular Disorder Diagnostic Index and Fonseca’s Anamnestic Index. Results: Of the 106 subjects, 26 (24.5% of the total) with vertical mandibular symmetry and 39 (36.8%) with vertical mandibular asymmetry were positive for TMD symptoms. By contrast, 17 patients (16.0% of the total) with vertical condylar symmetry and 24 patients (22.6%) with vertical mandibular asymmetry were regarded negative for TMD symptoms. There was no significant difference (p=0.520) in TMD symptoms based on vertical mandibular symmetry. Conclusion: The results from this studied Sumatran population indicate that there are common TMD symptoms in young adult orthodontic patients, but there is no significant association between vertical mandibular asymmetry and TMD symptoms. Further study on the development of TMD, mandibular asymmetry and treatment planning for growing patients is suggested, using longitudinal and transitional approaches.

Patient satisfaction and dissatisfaction with mandibular two-implant overdentures using different attachment systems: 5-year outcomes.

PubMed

Al-Zubeidi, Mohammed I; Alsabeeha, Nabeel H M; Thomson, W Murray; Payne, Alan G T

2012-10-01

Different attachment systems for mandibular two-implant overdentures could influence levels of patient satisfaction. Positive consensus of the majority of patients being satisfied does not preclude the possibility of dissatisfaction for some. To evaluate patient satisfaction and dissatisfaction before and after 5 years of wearing mandibular two implant overdentures using different attachment systems ; to determine the prognostic relevance of pretreatment complete denture complaints to treatment outcomes. A total of 106 edentulous participants enrolled in a clinical trial completed a preliminary self-report inventory of their original complete denture complaints.New complete maxillary dentures and mandibular two-implant overdentures were provided to each participant using one of six different attachment systems. Patient satisfaction was determined at pretreatment; at baseline with mandibular two-implant overdenture insertion; and then annually for 5 years, using visual analogue and Likert-type scales. Patient satisfaction with mandibular two-implant overdentures showed significant changes pre- to posttreatment(baseline) in all domains, but these were significant immediately and maintained without further significance for 5 years, other than pain with the overdenture. After 5 years, no significant differences were observed with all the attachment systems. Highly significant differences were found with some social and psychological aspects by the fifth year compared to baseline. Diagnostic and prognostic indicators from a pretreatment inventory identified 12 participants (13.5%) who were dissatisfied. These indicators revealed a maladaptive predisposition to mandibular two-implant overdentures. The provision of mandibular two-implant overdentures will, in the majority of patients, significantly enhance levels of patient satisfaction for 5 years, as compared to complete mandibular dentures, regardless of the attachment system. Careful evaluation of pretreatment complaints with conventional dentures can possibly identify patient dissatisfaction with mandibular two-implant overdentures [corrected]. © 2010 Wiley Periodicals, Inc.

Posterior Mandibular Ridge Resorption Associated with Different Retentive Systems for Overdentures: A 7-Year Retrospective Preliminary Study.

PubMed

Elsyad, Moustafa Abdou; Mohamed, Shahinaz Sayed; Shawky, Ahmad Fathalla

This retrospective study compared posterior mandibular residual ridge resorption with two different retentive mechanisms for overdentures after 7 years. A convenience sample of 18 edentulous men was assigned to one of two equal groups. Two implants were placed in the mandibular canine areas for each patient using the conventional two-stage surgical protocol, and the implants were splinted with a round bar 3 months later. New mandibular overdentures were then connected to the bars with clips (clip-retained overdentures, CR group) or resilient liners (resilient liner-retained overdentures, RR group). Posterior mandibular ridge resorption (PMRR) was recorded using proportional measurements and posterior area index (PAI) on panoramic radiographs taken immediately after overdenture insertion (T 0 ) and 7 years later (T 7 ). A linear regression model was used to verify the relationship between PAI and the following considerations: attachment type, age, initial mandibular ridge height, period of mandibular edentulism, number of previously worn dentures, and relining events. After 7 years, the RR group demonstrated a significantly (P = .014) higher change in PAI (0.11 ± 0.02) than the CR group (0.06 ± 0.04). The average PMRR for each mm of posterior mandibular ridge was 0.79 mm (0.11 mm/year) in the CR group and 1.4 mm (0.2 mm/year) in the RR group. Attachment type, initial mandibular ridge height, and relining times were significantly correlated with change in the PAI (P = .004, P = .035, and P = .045, respectively). Within the limitations of this preliminary study's design, it was observed that following a 7-year period of use, resilient liner attachments for bar/implant-retained overdentures appear to be associated with greater posterior mandibular ridge resorption when compared to clip attachments.

Surgical treatment of comminuted mandibular fractures using a low-profile locking mandibular reconstruction plate system

PubMed Central

Kanno, Takahiro; Sukegawa, Shintaro; Nariai, Yoshiki; Tatsumi, Hiroto; Ishibashi, Hiroaki; Furuki, Yoshihiko; Sekine, Joji

2014-01-01

Objective: The treatment of comminuted mandibular fractures is challenging due to the severity of associated injuries and the need for a careful diagnosis with adequate treatment planning. Recently, open reduction and stable internal fixation (OR-IF) with a load-bearing reconstruction plate have been advocated for reliable clinical outcomes with minimal complications. This clinical prospective study evaluated OR-IF in the surgical management of comminuted mandibular fractures with a new low-profile, thin, mandibular locking reconstruction plate. Materials and Methods: We prospectively assessed OR-IF of comminuted mandibular fractures with a low-profile locking mandibular reconstruction plate in 12 patients (nine men, three women; mean age 32.2 [range 16-71] years) between April 2010 and December 2011. The clinical characteristics and associated clinical parameters of patients were evaluated over a minimum follow-up period of 12 months. Results: Traffic accidents caused 50% of the fractures, followed by falls (25%). Four patients (33.3%) had associated midfacial maxillofacial fractures, while five patients had other mandibular fractures. Seven patients (58.3%) needed emergency surgery, mostly for airway management. Anatomical reduction of the comminuted segments re-established the mandibular skeleton in stable occlusion with rigid IF via extraoral (33.3%), intraoral (50%), or combined (16.7%) approaches. Immediate functional recovery was achieved. Sound bone healing was confirmed in all patients, with no complications such as malocclusion, surgical site infection, or malunion with a mean follow-up of 16.3 (range 12-24) months. Conclusions: OR-IF using a low-profile reconstruction plate system is a reliable treatment for comminuted mandibular fractures, enabling immediate functional recovery with good clinical results. PMID:25593862

Multifactorial etiology of Torus mandibularis: study of twins.

PubMed

Auškalnis, Adomas; Rutkūnas, Vygandas; Bernhardt, Olaf; Šidlauskas, Mantas; Šalomskienė, Loreta; Basevičienė, Nomeda

2015-01-01

The aim of this study is to investigate the multifactorial etiology of mandibular tori analyzing the influence of genetics, occlusal overload, various clinical variables and their interactions. Overall, plaster casts of 162 twins (81 twin pairs) were analyzed for the presence or absence of mandibular tori. Atypical wear facets on canine tips or incisors were recorded to diagnose bruxism. Angle Class, any kind of anterior open bite and positive, negative or flat curve of Wilson were recorded. Zygosity determination was carried out using a DNA test. Mandibular tori were found in 56.8% of the cases. In 93.6% of all monozygotic twin pairs both individuals had or did not have mandibular tori (κ=0.96±0.04; p<0.001), compared to 79.4% concordance of mandibular tori in dizygotic co-twins (κ=0.7±0.12; p<0.001). Prevalence of mandibular tori was significantly higher in the group of bruxers (67.5%) compared to non-bruxers (31.3%) (p<0.001). Significant association between mandibular tori and negative or flat curve of Wilson in the maxillary second premolars and first molars was found (OR=2.55, 95% CI (1.19-5.46), p=0.016). In all monozygotic bruxers, 97.1% showed concordance of mandibular tori presence in both co-twins compared to 78.9% dizygotic bruxers, and this difference is statistically significant (p=0.007). Our results suggest that the mandibular tori are of a multifactorial origin. Mandibular tori seem to have genetic predisposition, and may be associated with teeth grinding as well as with negative or flat CW in region of maxillary second premolar and first molar.

Systemic Nicotine Increases Gain and Narrows Receptive Fields in A1 via Integrated Cortical and Subcortical Actions

PubMed Central

Intskirveli, Irakli

2017-01-01

Abstract Nicotine enhances sensory and cognitive processing via actions at nicotinic acetylcholine receptors (nAChRs), yet the precise circuit- and systems-level mechanisms remain unclear. In sensory cortex, nicotinic modulation of receptive fields (RFs) provides a model to probe mechanisms by which nAChRs regulate cortical circuits. Here, we examine RF modulation in mouse primary auditory cortex (A1) using a novel electrophysiological approach: current-source density (CSD) analysis of responses to tone-in-notched-noise (TINN) acoustic stimuli. TINN stimuli consist of a tone at the characteristic frequency (CF) of the recording site embedded within a white noise stimulus filtered to create a spectral “notch” of variable width centered on CF. Systemic nicotine (2.1 mg/kg) enhanced responses to the CF tone and to narrow-notch stimuli, yet reduced the response to wider-notch stimuli, indicating increased response gain within a narrowed RF. Subsequent manipulations showed that modulation of cortical RFs by systemic nicotine reflected effects at several levels in the auditory pathway: nicotine suppressed responses in the auditory midbrain and thalamus, with suppression increasing with spectral distance from CF so that RFs became narrower, and facilitated responses in the thalamocortical pathway, while nicotinic actions within A1 further contributed to both suppression and facilitation. Thus, multiple effects of systemic nicotine integrate along the ascending auditory pathway. These actions at nAChRs in cortical and subcortical circuits, which mimic effects of auditory attention, likely contribute to nicotinic enhancement of sensory and cognitive processing. PMID:28660244

HttQ111/+ Huntington's Disease Knock-in Mice Exhibit Brain Region-Specific Morphological Changes and Synaptic Dysfunction.

PubMed

Kovalenko, Marina; Milnerwood, Austen; Giordano, James; St Claire, Jason; Guide, Jolene R; Stromberg, Mary; Gillis, Tammy; Sapp, Ellen; DiFiglia, Marian; MacDonald, Marcy E; Carroll, Jeffrey B; Lee, Jong-Min; Tappan, Susan; Raymond, Lynn; Wheeler, Vanessa C

2018-01-01

Successful disease-modifying therapy for Huntington's disease (HD) will require therapeutic intervention early in the pathogenic process. Achieving this goal requires identifying phenotypes that are proximal to the HTT CAG repeat expansion. To use Htt CAG knock-in mice, precise genetic replicas of the HTT mutation in patients, as models to study proximal disease events. Using cohorts of B6J.HttQ111/+ mice from 2 to 18 months of age, we analyzed pathological markers, including immunohistochemistry, brain regional volumes and cortical thickness, CAG instability, electron microscopy of striatal synapses, and acute slice electrophysiology to record glutamatergic transmission at striatal synapses. We also incorporated a diet perturbation paradigm for some of these analyses. B6J.HttQ111/+ mice did not exhibit significant neurodegeneration or gliosis but revealed decreased striatal DARPP-32 as well as subtle but regional-specific changes in brain volumes and cortical thickness that parallel those in HD patients. Ultrastructural analyses of the striatum showed reduced synapse density, increased postsynaptic density thickness and increased synaptic cleft width. Acute slice electrophysiology showed alterations in spontaneous AMPA receptor-mediated postsynaptic currents, evoked NMDA receptor-mediated excitatory postsynaptic currents, and elevated extrasynaptic NMDA currents. Diet influenced cortical thickness, but did not impact somatic CAG expansion, nor did it show any significant interaction with genotype on immunohistochemical, brain volume or cortical thickness measures. These data show that a single HttQ111 allele is sufficient to elicit brain region-specific morphological changes and early neuronal dysfunction, highlighting an insidious disease process already apparent in the first few months of life.

Systemic Nicotine Increases Gain and Narrows Receptive Fields in A1 via Integrated Cortical and Subcortical Actions.

PubMed

Askew, Caitlin; Intskirveli, Irakli; Metherate, Raju

2017-01-01

Nicotine enhances sensory and cognitive processing via actions at nicotinic acetylcholine receptors (nAChRs), yet the precise circuit- and systems-level mechanisms remain unclear. In sensory cortex, nicotinic modulation of receptive fields (RFs) provides a model to probe mechanisms by which nAChRs regulate cortical circuits. Here, we examine RF modulation in mouse primary auditory cortex (A1) using a novel electrophysiological approach: current-source density (CSD) analysis of responses to tone-in-notched-noise (TINN) acoustic stimuli. TINN stimuli consist of a tone at the characteristic frequency (CF) of the recording site embedded within a white noise stimulus filtered to create a spectral "notch" of variable width centered on CF. Systemic nicotine (2.1 mg/kg) enhanced responses to the CF tone and to narrow-notch stimuli, yet reduced the response to wider-notch stimuli, indicating increased response gain within a narrowed RF. Subsequent manipulations showed that modulation of cortical RFs by systemic nicotine reflected effects at several levels in the auditory pathway: nicotine suppressed responses in the auditory midbrain and thalamus, with suppression increasing with spectral distance from CF so that RFs became narrower, and facilitated responses in the thalamocortical pathway, while nicotinic actions within A1 further contributed to both suppression and facilitation. Thus, multiple effects of systemic nicotine integrate along the ascending auditory pathway. These actions at nAChRs in cortical and subcortical circuits, which mimic effects of auditory attention, likely contribute to nicotinic enhancement of sensory and cognitive processing.

Early extraction of the mandibular third molar in case of eruption disturbances of the second molar.

PubMed

Kavadia, S; Antoniades, K; Kaklamanos, E; Antoniades, V; Markovitsi, E; Zafiriadis, L

2003-01-01

General consensus has been reached on extracting mandibular third molars when they are involved in pathologic processes. However, early extraction is advisable in cases of eruption disturbances of the mandibular second molar, before or during orthodontic treatment. Thirty-two patients with early extraction of the mandibular third molar before or during orthodontic treatment were examined. In these cases either the presence of the third molar presented an obstacle in the eruption path of the second, or third molar germ removal was considered beneficial to the course of orthodontic treatment. Early extraction of the mandibular third molar facilitates the eruption of the second molar, especially in cases where evidence of crowding and lack of space in the posterior mandibular region exist. Orthodontic treatment may, in some cases, aggravate eruption disturbances of the second molar.

Anatomy of Mandibular Vital Structures. Part I: Mandibular Canal and Inferior Alveolar Neurovascular Bundle in Relation with Dental Implantology

PubMed Central

Wang, Hom-Lay; Sabalys, Gintautas

2010-01-01

ABSTRACT Objectives It is critical to determine the location and configuration of the mandibular canal and related vital structures during the implant treatment. The purpose of the present study was to review the literature concerning the mandibular canal and inferior alveolar neurovascular bundle anatomical variations related to the implant surgery. Material and Methods Literature was selected through the search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular canal, inferior alveolar nerve, and inferior alveolar neurovascular bundle. The search was restricted to English language articles, published from 1973 to November 2009. Additionally, a manual search in the major anatomy, dental implant, prosthetic and periodontal journals and books were performed. Results In total, 46 literature sources were obtained and morphological aspects and variations of the anatomy related to implant treatment in posterior mandible were presented as two entities: intraosseous mandibular canal and associated inferior alveolar neurovascular bundle. Conclusions A review of morphological aspects and variations of the anatomy related to mandibular canal and mandibular vital structures are very important especially in implant therapy since inferior alveolar neurovascular bundle exists in different locations and possesses many variations. Individual, gender, age, race, assessing technique used and degree of edentulous alveolar bone atrophy largely influence these variations. It suggests that osteotomies in implant dentistry should not be developed in the posterior mandible until the position of the mandibular canal is established. PMID:24421958

Retrospective Analysis of Ossifying Fibroma of Jaw Bones Over a Period of 10 Years with Literature Review.

PubMed

Mohanty, Sujata; Gupta, Sunita; Kumar, Priya; Sriram, K; Gulati, Ujjwal

2014-12-01

The purpose of this retrospective analysis is to document and discuss the features, treatment rendered and result of 25 histologically proven cases of ossifying fibromas of jaw bones operated by a single surgeon over a period of 10 years. The records of ossifying fibroma were obtained from the archives of Oral and Maxillofacial Surgery at Maulana Azad Institute of Dental Sciences (MAIDS) from 2001 to 2011. Only those cases were included in the study where definitive surgery was performed based on clinical, radiological & histopathological features. Twenty-five patients were analyzed with a final diagnosis of ossifying fibroma comprising of 14 males (56 %) and 11 females (44 %). The age range was 11-45 years with a mean of 24.12 years. Mandible was involved in 72 % and maxilla in 28 % cases with a predominance of mandibular posterior [19 (76 %)] cases. The study showed similar findings in regard to clinical, radiographic & histological features of ossifying fibroma as compared to other studies. It also showed that the treatment rendered in the form of eneucleation, curettage or resection of the lesion depending on its stage and extent were adequate, as no recurrence has been reported till date. Enucleation is preferred in small and well demarcated lesions. Curettage should be done in relatively large lesions with ill defined borders, not involving basal bone of mandible or cortical perforation. Resection should be reserved for aggressive and extensive cases with involvement of basal bone or perforation of cortices.

Management of pediatric mandibular fracture using orthodontic vacuum-formed thermoplastic splint: A case report and review of literature.

PubMed

Sanu, O O; Ayodele, Aos; Akeredolu, M O

2017-05-01

Fractures of the mandible are relatively less frequent in children when compared to adults. The anatomic features of children are protected. Children have a higher adaptation to maxillofacial fractures compared to adults. Treatment principles of mandibular fractures in children differ from that of adults due to concerns regarding mandibular growth and the developing dentition. A case of a 6-year-old boy with fractured mandibular symphysis managed by closed reduction using a vacuum formed thermoplastic splint and circummandibular wiring is presented. This article also provides a review of the literature regarding the management of mandibular fracture in young children.

[Topographological-anatomic changes in the structure of temporo-mandibular joint in case of fracture of the mandible condylar process at cervical level].

PubMed

Volkov, S I; Bazhenov, D V; Semkin, V A

2011-01-01

Pathological changes in soft tissues surrounding the fracture site as well as in the structural elements of temporo-mandibular joint always occured in condylar process fracture with shift at cervical mandibular jaw level. Other changes were also seen in the joint on the opposite normal side. Modelling of condylar process fracture at mandibular cervical level by means of three-dimensional computer model of temporo-mandibular joint contributed to proper understanding of this pathology emergence as well as to prediction and elimination of disorders arising in adjacent to the fracture site tissues.

Mandibular Symmetrical Bilateral Canine-Lateral Incisors Transposition: Its Early Diagnosis and Treatment Considerations.

PubMed

Shapira, Yehoshua; Finkelstein, Tamar; Kadry, Rana; Schonberger, Shirley; Shpack, Nir

2016-01-01

Bilateral mandibular tooth transposition is a relatively rare dental anomaly caused by distal migration of the mandibular lateral incisors and can be detected in the early mixed dentition by radiographic examination. Early diagnosis and interceptive intervention may reduce the risk of possible transposition between the mandibular canine and lateral incisor. This report illustrates the orthodontic management of bilateral mandibular canine-lateral incisor transposition. Correct positioning of the affected teeth was achieved on the left side while teeth on the right side were aligned in their transposed position. It demonstrates the outcome of good alignment of the teeth in the dental arch.

Determining the anatomy of the descending palatine artery and pterygoid plates with computed tomography in Class III patients.

PubMed

Ueki, Koichiro; Hashiba, Yukari; Marukawa, Kohei; Nakagawa, Kiyomasa; Okabe, Katsuhiko; Yamamoto, Etsuhide

2009-12-01

Understanding the anatomy of the pterygomaxillary junction region helps prevent blood loss in Le Fort I osteotomy. Here, we determined the location of the descending palatine artery and the structure of the pterygomaxillary region. The study group consisted of 82 Japanese patients with mandibular prognathism and asymmetry, with and without maxillary retrognathism or asymmetry. A total of 164 sides were measured and divided into right versus left, men versus women, and bimaxillary osteotomy (B) versus mandibular osteotomy (S). Lateral and frontal cephalograms and computed tomography (CT) were analysed for all patients. The relationship between the cephalometric measurements and the measurements of the descending palatine artery and pterygoid plate (PP) were assessed. There were no significant correlations between measurements of cephalograms and those of the descending palatine artery and PPs. There were significant differences between right and left in lateral plate length (p=0.0014) and thickness of PP (p=0.0047). There were significant differences between men and women in right width of PP (p=0.0034), right thickness of PP (p=0.0063), left posterior length (p=0.0196), and left thickness of PP (p=0.0279). The B group had a shorter anterior length than the S group (right: p<0.0001, left: p=0.0027). These results suggest that the location of the descending palatine artery and the morphology of the PPs were not significantly associated with any cephalometric measurements. CT examination is necessary to recognize the anatomy of pterygomaxillary region and the exact positions of descending palatine artery before Le Fort I osteotomy.

A Comparative Study on the Efficacy of Submucosal Injection of Dexamethasone Versus Methylprednisolone in Reducing Postoperative Sequelae After Third Molar Surgery.

PubMed

Lim, Daniel; Ngeow, Wei Cheong

2017-11-01

To compare the efficacy of preoperative submucosal injection of 4 mg of dexamethasone versus 40 mg of methylprednisolone in reducing postoperative sequelae after surgical removal of impacted mandibular third molars. This prospective, randomized, double-blind study included 65 patients who required surgical removal of impacted mandibular third molars with Class II or position B impaction (Pell and Gregory classification). Patients were randomly assigned to 1 of 3 groups: dexamethasone, methylprednisolone, or placebo (control). Surgery was performed with patients under local anesthesia. Baseline measurements were obtained preoperatively, and subsequent assessments were made on postoperative day 1, 2, 5, and 7 to measure postoperative facial swelling by use of 2 linear measurements: interincisal mouth opening width and visual analog scale score for pain. The amount of analgesics consumed was recorded. Wound healing also was assessed on postoperative day 7. Descriptive and multivariate statistics were computed, and significance was set at P < .05. Both methylprednisolone and dexamethasone significantly reduced swelling and trismus (P < .05, Kruskal-Wallis test), whereas the methylprednisolone group had significantly less pain (P < .05, Kruskal-Wallis test) and consumed a lower amount of analgesics (P < .05, χ 2 test) during the early postoperative days. The study findings suggest that a single preoperative dose of dexamethasone versus methylprednisolone was equally effective in reducing postoperative swelling and trismus. Pain control by these corticosteroids, however, was variable. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Bilateral mandibular angle fractures: clinical considerations.

PubMed

Boffano, Paolo; Roccia, Fabio

2010-03-01

The mandibular angle is a frequent site of fracture. It is a weak zone that is more exposed to fractures than other areas of the mandibular bone. The presence of incompletely erupted third molars is associated with a further increased risk of angle fractures. Our objective was to evaluate and discuss the surgical outcomes of a group of patients with bilateral mandibular angle fractures.In our study, patients with bilateral mandibular angle fractures surgically treated from January 1, 2001, to June 30, 2009, at the Division of Maxillofacial Surgery of the University of Turin were retrospectively analyzed. A combined transbuccal and intraoral approach or an intraoral approach only was adopted.Eight patients (7 men and 1 woman) underwent surgery for bilateral mandibular angle fractures. Good to satisfactory reduction of the fractures was obtained with both surgical techniques. Good to fair restored occlusion was observed postoperatively in all patients.Successful treatment of bilateral mandibular angle fractures may be achieved via different techniques. Superficially impacted third molars seem to be associated with an increased risk of angle fractures. Bilateral angle fractures are an ideal model to study the biomechanical pathogenesis of angle fractures.

Chincup treatment modifies the mandibular shape in children with prognathism.

PubMed

Alarcón, José Antonio; Bastir, Markus; Rosas, Antonio; Molero, Julia

2011-07-01

Although chincups are the preferred treatment for growing children with mandibular prognathism, the mechanism by which chincups improve this condition remains unclear. The aim of this study was to use geometric morphometrics to evaluate changes in the shape of the mandible of prognathic children treated with a chincup. Geometric morphometrics were used to evaluate the short-term mandibular shape changes in 50 prognathic children treated with chincups compared with 40 untreated matched controls. Twenty-one 2-dimensional mandibular landmarks from cephalograms taken before and after 36 months of treatment or observation were analyzed by Procrustes superimposition and thin plate spline. Permutation tests of the treated patients showed highly significant differences in the mandibular shapes before and after treatment, and compared with the control group after the observation period. The thin plate spline grid deformations indicated more rectangular mandibular configuration, forward condyle orientation, condyle neck compression, gonial area compression, and symphysis narrowing. Early chincup treatment widely modifies the mandibular shape of prognathic children to improve Class III malocclusion. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Reporting numeric values of complete crowns. Part 1: Clinical preparation parameters.

PubMed

Tiu, Janine; Al-Amleh, Basil; Waddell, J Neil; Duncan, Warwick J

2015-07-01

An implemented objective measuring system for measuring clinical tooth preparations does not exist. The purpose of this study was to compare clinically achieved tooth preparations for ceramic crowns by general dentists with the recommended values in the literature with an objective measuring method. Two hundred thirty-six stone dies prepared for anterior and posterior complete ceramic crown restorations (IPS e.max Press; Ivoclar Vivadent) were collected from dental laboratories. The dies were scanned and analyzed using the coordinate geometry method. Cross-sectioned images were captured, and the average total occlusal convergence angle, margin width, and abutment height for each preparation was measured and presented with associated 95% confidence intervals. The average total occlusal convergence angles for each tooth type was above the recommended values reported in the literature. The average margin widths (0.40 to 0.83 mm) were below the minimum recommended values (1 to 1.5 mm). The tallest preparations were maxillary canines (5.25 mm), while the shortest preparations were mandibular molars (1.87 mm). Complete crown preparations produced in general practice do not achieve the recommended values found in the literature. However, these recommended values are not based on clinical trials, and the effects of observed shortfalls on the clinical longevity of these restorations are not predictable. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

[Fabrication and accuracy research on 3D printing dental model based on cone beam computed tomography digital modeling].

PubMed

Zhang, Hui-Rong; Yin, Le-Feng; Liu, Yan-Li; Yan, Li-Yi; Wang, Ning; Liu, Gang; An, Xiao-Li; Liu, Bin

2018-04-01

The aim of this study is to build a digital dental model with cone beam computed tomography (CBCT), to fabricate a virtual model via 3D printing, and to determine the accuracy of 3D printing dental model by comparing the result with a traditional dental cast. CBCT of orthodontic patients was obtained to build a digital dental model by using Mimics 10.01 and Geomagic studio software. The 3D virtual models were fabricated via fused deposition modeling technique (FDM). The 3D virtual models were compared with the traditional cast models by using a Vernier caliper. The measurements used for comparison included the width of each tooth, the length and width of the maxillary and mandibular arches, and the length of the posterior dental crest. 3D printing models had higher accuracy compared with the traditional cast models. The results of the paired t-test of all data showed that no statistically significant difference was observed between the two groups (P>0.05). Dental digital models built with CBCT realize the digital storage of patients' dental condition. The virtual dental model fabricated via 3D printing avoids traditional impression and simplifies the clinical examination process. The 3D printing dental models produced via FDM show a high degree of accuracy. Thus, these models are appropriate for clinical practice.

Effects of self-adjusting file, Mtwo, and ProTaper on the root canal wall.

PubMed

Hin, Ellemieke S; Wu, Min-Kai; Wesselink, Paul R; Shemesh, Hagay

2013-02-01

The purpose of this ex vivo study was to observe the incidence of cracks in root dentin after root canal preparation with hand files, self-adjusting file (SAF), ProTaper, and Mtwo. One hundred extracted mandibular premolars with single canals were randomly selected. Two angulated radiographs were taken for each tooth, and the width of the canal was measured at 9 mm from the apex. Five groups of 20 teeth each were comparable in canal width. The control group was left unprepared. Four experimental groups were instrumented with hand files, ProTaper, Mtwo, and SAF. Roots were then sectioned horizontally and observed under a microscope. The presence of dentinal cracks and their location were noted. The difference between the experimental groups was analyzed with a χ(2) test. No cracks were observed in the control group. In the experimental groups, ProTaper, Mtwo, and SAF caused cracks in 35%, 25%, and 10% of teeth, respectively. The hand-file group did not show any dentinal cracks (P < .0001). ProTaper and Mtwo caused more cracks than hand files (P < .05), but SAF did not (P > .05). Instrumentation of root canals with SAF, Mtwo, and ProTaper could cause damage to root canal dentin. SAF has a tendency to cause less dentinal cracks as compared with ProTaper or Mtwo. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Three-dimensional facial distances of Northern Sudanese persons from childhood to young adulthood.

PubMed

Sforza, Chiarella; Dolci, Claudia; Tommasi, Davide G; Pisoni, Luca; De Menezes, Marcio; Elamin, Fadil

2014-07-01

No current age- and gender-related normative data exist for the dimensions of facial structures in Northern Sudanese subjects. In the current study information about normal sex- and age-related linear distances is provided. The three-dimensional coordinates of 14 landmarks on the facial soft tissues were obtained using a hand-held laser scanner in 653 healthy Northern Sudanese subjects (326 males and 327 females) aged 4-30 years. From the landmarks, 13 linear distances were calculated, and averaged for age and sex. Comparisons were performed by factorial analysis of variance. All analyzed linear soft tissue facial dimensions were significantly larger in men than in women (p < 0.01), except mouth width (ch-ch), upper facial height (n-sn), mandibular body length (pg-go) and width (go-go). All measurements underwent significant modifications as a function of age (p < 0.01), with significant age × sex interactions (p < 0.01) for all linear dimensions except lower face height (sn-pg). Overall, when compared to literature data for African and Caucasoid subjects, several differences were found, pointing to the necessity of ethnic-specific data. Data collected in the present investigation could serve as a database for the quantitative description of human facial morphology during normal growth and development. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Effects on G Tolerance While Biting Down on a Mandibular Orthopedic Repositioning Appliance (MORA) Levels.

DTIC Science & Technology

1990-10-01

Repositioning Appliance (MORA) that properly aligns the temporo mandibular joint (TMJ) requires voluntary contraction of the masseter and temporal’s...growth, malocclusion, or bad oral posture may cause the Temporo Mandibular Joint (TMJ) to grad- ually become misaligned. The masseter and other muscles...books have been published on the use of a Mandibular Orthopedic Repositioning Appliance (MORA) to realign the joint (Figure 1). Realignment is claimed

Evaluation of the relationship between mandibular third molar and mandibular canal by different algorithms of cone-beam computed tomography.

PubMed

Mehdizadeh, Mojdeh; Ahmadi, Navid; Jamshidi, Mahsa

2014-11-01

Exact location of the inferior alveolar nerve (IAN) bundle is very important. The aim of this study is to evaluate the relationship between the mandibular third molar and the mandibular canal by cone-beam computed tomography. This was a cross-sectional study with convenience sampling. 94 mandibular CBCTs performed with CSANEX 3D machine (Soredex, Finland) and 3D system chosen. Vertical and horizontal relationship between the mandibular canal and the third molar depicted by 3D, panoramic reformat view of CBCT and cross-sectional view. Cross-sectional view was our gold standard and other view evaluated by it. There were significant differences between the vertical and horizontal relation of nerve and tooth in all views (p < 0.001). The results showed differences in the position of the inferior alveolar nerve with different views of CBCT, so CBCT images are not quite reliable and have possibility of error.

Adaptive plasticity in mammalian masticatory joints

NASA Astrophysics Data System (ADS)

Ravosa, Matthew J.; Kunwar, Ravinder; Nicholson, Elisabeth K.; Klopp, Emily B.; Pinchoff, Jessie; Stock, Stuart R.; Stack, M. Sharon; Hamrick, Mark W.

2006-08-01

Genetically similar white rabbits raised on diets of different mechanical properties, as well as wild-type and myostatin-deficient mice raised on similar diets, were compared to assess the postweaning effects of elevated masticatory loads due to increased jaw-adductor muscle and bite forces on the proportions and properties of the mandibular symphysis and temporomandibular joint (TMJ). Microcomputed tomography (microCT) was used to quantify bone structure at a series of equidistant external and internal sites in coronal sections for a series of joint locations. Discriminant function analyses and non-parametric ANOVAs were used to characterize variation in biomineralization within and between loading cohorts. In both species, long-term excessive loading results in larger joint proportions, thicker articular and cortical bone, and increased biomineralization of hard tissues. Such adaptive plasticity appears designed to maintain the postnatal integrity of masticatory joint systems for a primary loading environment(s). This behavioral signal may be increasingly mitigated in older organisms by the interplay between adaptive and degradative joint tissue responses.

Chondroblastic osteosarcoma mimicking periapical abscess

PubMed Central

YAMAMOTO-SILVA, Fernanda Paula; SILVA, Brunno Santos de Freitas; BATISTA, Aline Carvalho; de MENDONÇA, Elismauro Francisco; PINTO-JÚNIOR, Décio dos Santos; ESTRELA, Carlos

2017-01-01

Abstract Lesions of non-endodontic origin may mimic periapical abscess. Osteosarcoma is a rare malignant lesion. Case report The present report describes a case of chondroblastic osteosarcoma in the periapical region of teeth #29, #30, and #31 of an 18-year-old male. Clinical history showed self-reported discomfort in the right posterior gingiva for over a month. Physical examination showed a small expansion and redness of the right mandibular buccal and lingual cortical plates, but no signs of pain or inflammation were observed. All the teeth responded positively to pulp sensibility. Periapical and panoramic radiographs showed slight periapical radiolucency in the roots of teeth #29 and #30, clear periodontal ligament space widening, and evident loss of lamina dura. Incisional biopsy was performed, and based on microscopic findings the diagnosis of chondroblastic osteosarcoma was confirmed. Conclusions Non-endodontic diseases associated with tooth root apex, such as chondroblastic osteosarcoma, should be included in differential diagnosis of jaw lesions that resemble periapical abscess. PMID:28877285

Spontaneous emergence of overgrown molar teeth in a colony of Prairie voles (Microtus ochrogaster)

PubMed Central

Jheon, Andrew H; Prochazkova, Michaela; Sherman, Michael; Manoli, Devanand S; Shah, Nirao M; Carbone, Lawrence; Klein, Ophir

2015-01-01

Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles (Microtus ochrogaster). We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography (microCT) analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth. PMID:25634121

Effects of incisor extraction on jaw and tongue motor representations within face sensorimotor cortex of adult rats.

PubMed

Avivi-Arber, Limor; Lee, Jye-Chang; Sessle, Barry J

2010-04-01

Loss of teeth is associated with changes in somatosensory inputs and altered patterns of mastication, but it is unclear whether tooth loss is associated with changes in motor representations within face sensorimotor cortex of rats. We used intracortical microstimulation (ICMS) and recordings of cortically evoked muscle electromyographic (EMG) activities to test whether changes occur in the ICMS-defined motor representations of the left and right jaw muscles [masseter, anterior digastric (LAD, RAD)] and tongue muscle [genioglossus (GG)] within the cytoarchitectonically defined face primary motor cortex (face-M1) and adjacent face primary somatosensory cortex (face-S1) 1 week following extraction of the right mandibular incisor in anesthetized (ketamine-HCl) adult male Sprague-Dawley rats. Under local and general anesthesia, an "extraction" group (n = 8) received mucoalveolar bone surgery and extraction of the mandibular right incisor. A "sham-extraction" group (n = 6) received surgery with no extraction. A "naive" group (n = 6) had neither surgery nor extraction. Data were compared by using mixed-model repeated-measures ANOVA. Dental extraction was associated with a significantly increased number of sites within face-M1 and face-S1 from which ICMS evoked RAD EMG activities, a lateral shift of the RAD and LAD centers of gravity within face-M1, shorter onset latencies of ICMS-evoked GG activities within face-M1 and face-S1, and an increased number of sites within face-M1 from which ICMS simultaneously evoked RAD and GG activities. Our novel findings suggest that dental extraction may be associated with significant neuroplastic changes within the rat's face-M1 and adjacent face-S1 that may be related to the animal's ability to adapt to the altered oral state. (c) 2009 Wiley-Liss, Inc.

Impact of mandibular invasion on prognosis in oral squamous cell carcinoma four centimeters or less in size.

PubMed

Fives, Cassie; Nae, Andreea; Roche, Phoebe; O'Leary, Gerard; Fitzgerald, Brendan; Feeley, Linda; Sheahan, Patrick

2017-04-01

Previous studies have reported variable results for the impact of bone invasion on survival in oral cancer. It is unclear whether bone invasion in small (≤4 cm) squamous cell carcinomas (SCC) of the oral cavity is an independent adverse prognosticator. Our objective was to investigate impact on survival of bone invasion in SCC of floor of mouth (FOM), lower alveolus (LA), and retromolar trigone (RMT) ≤4 cm in size. Retrospective study of 96 patients with SCC of the FOM, LA, and RMT undergoing primary surgical treatment. Original pathology reports and slides were reviewed by three pathologists. Level of bone invasion was categorized as cortical or medullary. Main outcome measures were local control (LC) and overall survival (OS). Bone invasion was present in 31 cases (32%). On review of pathology slides, all cases of bone invasion demonstrated medullary involvement. Median follow-up was 36 months for all patients, and 53 months for patients not dying from cancer. Among tumors ≤4 cm, bone invasion was associated with significantly worse LC (P =.04) and OS (P =.0005). Medullary invasion (hazard ratio: 2.2, 95% confidence interval: 1.1-4.4, P =.03), postoperative radiotherapy (hazard ratio: 0.3, 95% confidence interval: 0.1-0.5, P <.001), and positive pathologic nodal status (hazard ratio: 4.1, 95% confidence interval: 1.9-8.6, P <.001) were independent predictors of worse OS among the entire cohort. Mandibular medullary bone invasion is a poor prognosticator in oral cancers, irrespective of small size of primary tumor. Such cases should be considered for postoperative radiotherapy. 4. Laryngoscope, 127:849-854, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

An orthodontic technique for minimally invasive extraction of impacted lower third molar.

PubMed

Ma, Zhi-Gui; Xie, Qian-Yang; Yang, Chi; Xu, Guang-Zhou; Cai, Xie-Yi; Li, Jie-Yan

2013-08-01

To present a novel orthodontic approach for minimally invasive extraction of impacted mandibular third molars (M3s) close to the inferior alveolar nerve (IAN). Eight patients (8 M3s) requiring extraction of M3s were included in this study; there were 2 cases of horizontal impaction, 4 of mesioangular impaction, and 2 of vertical impaction. Cone-beam computed tomogram showed that the roots of impacted M3s in 2 cases interrupted the cortices of the mandibular canal, and those in the other 6 cases were very close to the IAN. Orthodontic treatment was performed in this study. The crowns of 5 impacted teeth were surgically exposed before the application of the orthodontic device, whereas bonding was performed directly to the occlusal surface of the other 3 M3s, which had partially erupted. The opposing maxillary M3s were removed in 3 cases. One-step orthodontic extraction was applied to vertically impacted M3s and 2-step treatment was applied to horizontally or mesioangularly impacted M3s. Success was defined as the separation of the impacted tooth from the IAN as visualized on cone-beam computed tomogram. After orthodontic treatment, all impacted M3s were extruded and separated from the IAN (mean, 6.6 months; range, 4 to 10 months), without any neurologic consequences. The average time of extraction was 5 minutes. In all 8 cases, new bone formation occurred distal to the adjacent second molar. This orthodontic technique may be a minimally invasive approach for the extraction of impacted M3s adjacent to the IAN, with a decreased risk of paresthesias and with osteoperiodontal advantages. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Computer-Aided Process Planning for the Layered Fabrication of Porous Scaffold Matrices

NASA Astrophysics Data System (ADS)

Starly, Binil

Rapid Prototyping (RP) technology promises to have a tremendous impact on the design and fabrication of porous tissue replacement structures for applications in tissue engineering and regenerative medicine. The layer-by-layer fabrication technology enables the design of patient-specific medical implants and complex structures for diseased tissue replacement strategies. Combined with advancements in imaging modalities and bio-modeling software, physicians can engage themselves in advanced solutions for craniofacial and mandibular reconstruction. For example, prior to the advancement of RP technologies, solid titanium parts used as implants for mandibular reconstruction were fashioned out of molding or CNC-based machining processes (Fig. 3.1). Titanium implants built using this process are often heavy, leading to increased patient discomfort. In addition, the Young's modulus of titanium is almost five times that of healthy cortical bone resulting in stress shielding effects [1,2]. With the advent of CAD/CAM-based tools, the virtual reconstruction of the implants has resulted in significant design improvements. The new generation of implants can be porous, enabling the in-growth of healthy bone tissue for additional implant fixation and stabilization. Newer implants would conform to the external shape of the defect site that is intended to be filled in. More importantly, the effective elastic modulus of the implant can be designed to match that of surrounding tissue. Ideally, the weight of the implant can be designed to equal the weight of the tissue that is being replaced resulting in increased patient comfort. Currently, such porous structures for reconstruction can only be fabricated using RP-based metal fabrication technologies such as Electron Beam Melting (EBM), Selective Laser Sintering (SLS®), and 3D™ Printing processes.

Mandibular gland secretions of meliponine worker bees: further evidence for their role in interspecific and intraspecific defence and aggression and against their role in food source signalling.

PubMed

Schorkopf, Dirk Louis P; Hrncir, Michael; Mateus, Sidnei; Zucchi, Ronaldo; Schmidt, Veronika M; Barth, Friedrich G

2009-04-01

Like ants and termites some species of stingless bees (Meliponini), which are very important pollinators in the tropics, use pheromone trails to communicate the location of a food source. We present data on the communicative role of mandibular gland secretions of Meliponini that resolve a recent controversy about their importance in the laying of such trails. Volatile constituents of the mandibular glands have been erroneously thought both to elicit aggressive/defensive behaviour and to signal food source location. We studied Trigona spinipes and Scaptotrigona aff. depilis ('postica'), two sympatric species to which this hypothesis was applied. Using extracts of carefully dissected glands instead of crude cephalic extracts we analysed the substances contained in the mandibular glands of worker bees. Major components of the extracts were 2-heptanol (both species), nonanal (T. spinipes), benzaldehyde and 2-tridecanone (S. aff. depilis). The effect of mandibular gland extracts and of individual components thereof on the behaviour of worker bees near their nest and at highly profitable food sources was consistent. Independent of the amount of mandibular gland extract applied, the bees overwhelmingly reacted with defensive behaviour and were never attracted to feeders scented with mandibular gland extract or any of the synthetic chemicals tested. Both bee species are capable of using mandibular gland secretions for intra- and interspecific communication of defence and aggression and share 2-heptanol as a major pheromone compound. While confirming the role of the mandibular glands in nest defence, our experiments provide strong evidence against their role in food source signalling.

Mechanical force-mediated pathological cartilage thinning is regulated by necroptosis and apoptosis.

PubMed

Zhang, C; Lin, S; Li, T; Jiang, Y; Huang, Z; Wen, J; Cheng, W; Li, H

2017-08-01

This study aimed to identify the mechanisms underlying mandibular chondrocyte cell death and cartilage thinning in response to mechanical force. An in vivo model (compressive mechanical force) and an in vitro model (TNF-α+cycloheximide) were used to induce mandibular chondrocyte necroptosis. Hematoxylin and eosin staining and transmission electron microscopy were used to assess histological and subcellular changes in mandibular chondrocyte. Immunohistochemistry, western blotting, and real-time PCR were performed to evaluate changes in necroptotic protein markers. Cell activity, mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) were examined in vitro. The expression of RIP1, RIP3 and Caspase-8 in mandibular chondrocytes significantly increased after 4 days of compressive mechanical force. Furthermore, the inhibition of necroptosis by Necrostatin-1 (Nec-1) or the inhibition of apoptosis by N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD) partially restored mechanical force-mediated mandibular cartilage thinning and chondrocyte death. Moreover, a synergistic effect on cell death inhibition and mandibular cartilage thickness restoration were found when treated with Nec-1+Z-VAD. The results of the in vitro model were in line with the in vivo ones, indicating that the changes in MMP and ROS generation contributed to mandibular chondrocyte apoptosis and necroptosis. In addition to apoptosis, necroptosis also plays critical roles in pathological changes in mandibular cartilage after compressive mechanical force stimulation, implying RIP1, a master protein that mediates both necroptosis and apoptosis, as a potential therapeutic target in temporal mandibular osteoarthritis. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Comprehensive Analysis of Mandibular Residual Asymmetry after Bilateral Sagittal Split Ramus Osteotomy Correction of Menton Point Deviation

PubMed Central

Lin, Qiuping; Huang, Xiaoqiong; Xu, Yue; Yang, Xiaoping

2016-01-01

Purpose Facial asymmetry often persists even after mandibular deviation corrected by the bilateral sagittal split ramus osteotomy (BSSRO) operation, since the reference facial sagittal plane for the asymmetry analysis is usually set up before the mandibular menton (Me) point correction. Our aim is to develop a predictive and quantitative method to assess the true asymmetry of the mandible after a midline correction performed by a virtual BSSRO, and to verify its availability by evaluation of the post-surgical improvement. Patients and Methods A retrospective cohort study was conducted at the Hospital of Stomatology, Sun Yat-sen University (China) of patients with pure hemi-mandibular elongation (HE) from September 2010 through May 2014. Mandibular models were reconstructed from CBCT images of patients with pre-surgical orthodontic treatment. After mandibular de-rotation and midline alignment with virtual BSSRO, the elongation hemi-mandible was virtually mirrored along the facial sagittal plane. The residual asymmetry, defined as the superimposition and boolean operation of the mirrored elongation side on the normal side, was calculated, including the volumetric differences and the length of transversal and vertical asymmetry discrepancy. For more specific evaluation, both sides of the hemi-mandible were divided into the symphysis and parasymphysis (SP), mandibular body (MB), and mandibular angle (MA) regions. Other clinical variables include deviation of Me point, dental midline and molar relationship. The measurement of volumetric discrepancy between the two sides of post-surgical hemi-mandible were also calculated to verify the availability of virtual surgery. Paired t-tests were computed and the P value was set at .05. Results This study included 45 patients. The volume differences were 407.8±64.8 mm3, 2139.1±72.5 mm3, and 422.5±36.9 mm3; residual average transversal discrepancy, 1.9 mm, 1.0 mm, and 2.2 mm; average vertical discrepancy, 1.1 mm, 2.2 mm, and 2.2 mm (before virtual surgery). The post-surgical volumetric measurement showed no statistical differences between bilateral mandibular regions. Conclusions Mandibular asymmetry persists after Me point correction. A 3D quantification of mandibular residual asymmetry after Me point correction and mandible de-rotation with virtual BSSRO sets up a true reference mirror plane for comprehensive asymmetry assessment of bilateral mandibular structure, thereby providing an accurate guidance for orthognathic surgical planning. PMID:27571364

Comprehensive Analysis of Mandibular Residual Asymmetry after Bilateral Sagittal Split Ramus Osteotomy Correction of Menton Point Deviation.

PubMed

Lin, Han; Zhu, Ping; Lin, Qiuping; Huang, Xiaoqiong; Xu, Yue; Yang, Xiaoping

2016-01-01

Facial asymmetry often persists even after mandibular deviation corrected by the bilateral sagittal split ramus osteotomy (BSSRO) operation, since the reference facial sagittal plane for the asymmetry analysis is usually set up before the mandibular menton (Me) point correction. Our aim is to develop a predictive and quantitative method to assess the true asymmetry of the mandible after a midline correction performed by a virtual BSSRO, and to verify its availability by evaluation of the post-surgical improvement. A retrospective cohort study was conducted at the Hospital of Stomatology, Sun Yat-sen University (China) of patients with pure hemi-mandibular elongation (HE) from September 2010 through May 2014. Mandibular models were reconstructed from CBCT images of patients with pre-surgical orthodontic treatment. After mandibular de-rotation and midline alignment with virtual BSSRO, the elongation hemi-mandible was virtually mirrored along the facial sagittal plane. The residual asymmetry, defined as the superimposition and boolean operation of the mirrored elongation side on the normal side, was calculated, including the volumetric differences and the length of transversal and vertical asymmetry discrepancy. For more specific evaluation, both sides of the hemi-mandible were divided into the symphysis and parasymphysis (SP), mandibular body (MB), and mandibular angle (MA) regions. Other clinical variables include deviation of Me point, dental midline and molar relationship. The measurement of volumetric discrepancy between the two sides of post-surgical hemi-mandible were also calculated to verify the availability of virtual surgery. Paired t-tests were computed and the P value was set at .05. This study included 45 patients. The volume differences were 407.8±64.8 mm3, 2139.1±72.5 mm3, and 422.5±36.9 mm3; residual average transversal discrepancy, 1.9 mm, 1.0 mm, and 2.2 mm; average vertical discrepancy, 1.1 mm, 2.2 mm, and 2.2 mm (before virtual surgery). The post-surgical volumetric measurement showed no statistical differences between bilateral mandibular regions. Mandibular asymmetry persists after Me point correction. A 3D quantification of mandibular residual asymmetry after Me point correction and mandible de-rotation with virtual BSSRO sets up a true reference mirror plane for comprehensive asymmetry assessment of bilateral mandibular structure, thereby providing an accurate guidance for orthognathic surgical planning.

[Exploring a new method for superimposition of pre-treatment and post-treatment mandibular digital dental casts in adults].

PubMed

Dai, F F; Liu, Y; Xu, T M; Chen, G

2018-04-18

To explore a cone beam computed tomography (CBCT)-independent method for mandibular digital dental cast superimposition to evaluate three-dimensional (3D) mandibular tooth movement after orthodontic treatment in adults, and to evaluate the accuracy of this method. Fifteen post-extraction orthodontic treatment adults from the Department of Orthodontics, Peking University School and Hospital of Stomatology were included. All the patients had four first premolars extracted, and were treated with straight wire appliance. The pre- and post-treatment plaster dental casts and craniofacial CBCT scans were obtained. The plaster dental casts were transferred to digital dental casts by 3D laser scanning, and lateral cephalograms were created from the craniofacial CBCT scans by orthogonal projection. The lateral cephalogram-based mandibular digital dental cast superimposition was achieved by sequential maxillary dental cast superimposition registered on the palatal stable region, occlusal transfer, and adjustment of mandibular rotation and translation obtained from lateral cephalogram superimposition. The accuracy of the lateral cephalogram-based mandibular digital dental cast superimposition method was evaluated with the CBCT-based mandibular digital dental cast superimposition method as the standard reference. After mandibular digital dental cast superimposition using both methods, 3D coordinate system was established, and 3D displacements of the lower bilateral first molars, canines and central incisors were measured. Differences between the two superimposition methods in tooth displacement measurements were assessed using the paired t-test with the level of statistical significance set at P<0.05. No significant differences were found between the lateral cephalogram-based and CBCT-based mandibular digital dental cast superimposition methods in 3D displacements of the lower first molars, and sagittal and vertical displacements of the canines and central incisors; transverse displacements of the canines and central incisors differed by (0.3±0.5) mm with statistical significance. The lateral cephalogram-based mandibular digital dental cast superimposition method has the similar accuracy as the CBCT-based mandibular digital dental cast superimposition method in 3D evaluation of mandibular orthodontic tooth displacement, except for minor differences for the transverse displacements of anterior teeth. This method is applicable to adult patients with conventional orthodontic treatment records, especially the previous precious orthodontic data in the absence of CBCT scans.

[The transverse movement of the temporo-mandibular joint (translation movement) of the dog, also with reference to dysplasia of this joint in the dachshund].

PubMed

Vollmerhaus, B; Roos, H

1996-09-01

Contrary to the accepted opinion, transverse movement is possible in the temporo-mandibular joint of the dog. This movement is arched and is important for mastication. Analysis of transverse movement of the temporo-mandibular joint was done in 20 dog breeds. Accidentally dysplasia of the temporo-mandibular joint was found in the dachshund, a phenomenon which has not been described before.

Mandibular Third Molar Impaction: Review of Literature and a Proposal of a Classification

PubMed Central

Daugela, Povilas

2013-01-01

ABSTRACT Objectives The purpose of present article was to review impacted mandibular third molar aetiology, clinical anatomy, radiologic examination, surgical treatment and possible complications, as well as to create new mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results. Material and Methods Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular third molar, impacted mandibular third molar, inferior alveolar nerve injury third molar, lingual nerve injury third molar. The search was restricted to English language articles, published from 1976 to April 2013. Additionally, a manual search in the major anatomy and oral surgery journals and books was performed. The publications there selected by including clinical and human anatomy studies. Results In total 75 literature sources were obtained and reviewed. Impacted mandibular third molar aetiology, clinical anatomy, radiographic examination, surgical extraction of and possible complications, classifications and risk factors were discussed. New mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results was proposed. Conclusions The classification proposed here based on anatomical and radiological impacted mandibular third molar features is promising to be a helpful tool for impacted tooth assessment as well as for planning for surgical operation. Further clinical studies should be conducted for new classification validation and reliability evaluation. PMID:24422029

3-Dimensional Reproducibility of Natural Head Position

DTIC Science & Technology

2012-04-12

the “Six Elements to Orofacial Harmony”. He advocated using his Element II Analysis with natural head orientation for treatment planning, since “it...temporomandibular disorders, neck pain , headache, dentofacial structures, mandibular length, mandibular position, mandibular divergency and overjet (Cuccia, 2009

Prosthetic plate mandibular reconstruction.

PubMed

Davidson, M J; Gullane, P J

1991-12-01

The head and neck surgeon may choose one of several available methods to reconstruct the mandible following tumor ablation. This article discusses the use of metallic mandibular prostheses, the indications for alloplastic mandibular reconstruction, techniques of plate application (AO and THRP), and associated complications.

Prostaglandin E2 Increased Rat Cortical Bone Mass When Administered Immediately Following Ovariectomy

NASA Technical Reports Server (NTRS)

Ke, Hua Zhu; Jee, Webster S.S.; Zeng, Qing Qiang; Li, Mei; Lin, Bai Yun

1993-01-01

To investigate the effects of ovariectomy and the simultaneous administration of prostaglandin E2 (PGE2) on rat tibial shaft cortical bone histomorphometry, thirty-five 3 month-old female Sprague-Dawley rats were either ovariectomized (OVX), or sham ovariectomy (sham-OVX). The OVX rats were divided into three groups and treated with 0, 1 and 6 mg PGE2/kg/day for 90 days. The double fluorescent labeled undecalcified tibial shaft cross sections (proximal to the tibiofibular junction) of all the subjects were used for histomorphometry analysis. No differences in cross-sectional area and cortical bone area were found between sham-OVX and OVX controls, but OVX increased marrow area, intracortical porosity area and endocortical eroded perimeter. Periosteal and endocortical bone formation rates decreased with aging yet OVX prevented these changes. These OVX-induced increases in marrow area and endocortical eroded perimeter were prevented by 1 mg PGE2/kg/day treatment and added bone to periosteal and endocortical surfaces and to the marrow cavity. At the 6 mg/kg/day dose level, PGE2-treated OVX rats increased total tissue area, cortical bone area, marrow trabmular bone area, minimal cortical width and intracortical porosity area, and decreased marrow area compared to basal, sham-OVX and OVX controls. In addition, periosteal bone formation was elevated in the 6 mg PGE2/kg/day-treated OVX rats compared to OVX controls. Endocortical eroded perimeter increased from basal and sham-OVX control levels, but decreased from OVX control levels in the 6 mg PGE2/kg/day-treated OVX rats. Our study confirmed that ovariectomy does not cause osteopenia in tibial shaft cortical bone in rats, but it does stimulate endocortical bone resorption and enlarges marrow area. The new findings from the present study demonstrate that PGE2 prevents the OVX-induced increases in endocortical bone resorption and marrow area and adds additional bone to periosteal and endocortical surfaces and to marrow cavity to increase total bone mass in the tibial shaft of OVX rats when given immediately following ovafiectomy.

The role of pulvinar in the transmission of information in the visual hierarchy.

PubMed

Cortes, Nelson; van Vreeswijk, Carl

2012-01-01

VISUAL RECEPTIVE FIELD (RF) ATTRIBUTES IN VISUAL CORTEX OF PRIMATES HAVE BEEN EXPLAINED MAINLY FROM CORTICAL CONNECTIONS: visual RFs progress from simple to complex through cortico-cortical pathways from lower to higher levels in the visual hierarchy. This feedforward flow of information is paired with top-down processes through the feedback pathway. Although the hierarchical organization explains the spatial properties of RFs, is unclear how a non-linear transmission of activity through the visual hierarchy can yield smooth contrast response functions in all level of the hierarchy. Depending on the gain, non-linear transfer functions create either a bimodal response to contrast, or no contrast dependence of the response in the highest level of the hierarchy. One possible mechanism to regulate this transmission of visual contrast information from low to high level involves an external component that shortcuts the flow of information through the hierarchy. A candidate for this shortcut is the Pulvinar nucleus of the thalamus. To investigate representation of stimulus contrast a hierarchical model network of ten cortical areas is examined. In each level of the network, the activity from the previous layer is integrated and then non-linearly transmitted to the next level. The arrangement of interactions creates a gradient from simple to complex RFs of increasing size as one moves from lower to higher cortical levels. The visual input is modeled as a Gaussian random input, whose width codes for the contrast. This input is applied to the first area. The output activity ratio among different contrast values is analyzed for the last level to observe sensitivity to a contrast and contrast invariant tuning. For a purely cortical system, the output of the last area can be approximately contrast invariant, but the sensitivity to contrast is poor. To account for an alternative visual processing pathway, non-reciprocal connections from and to a parallel pulvinar like structure of nine areas is coupled to the system. Compared to the pure feedforward model, cortico-pulvino-cortical output presents much more sensitivity to contrast and has a similar level of contrast invariance of the tuning.

The Role of Pulvinar in the Transmission of Information in the Visual Hierarchy

PubMed Central

Cortes, Nelson; van Vreeswijk, Carl

2012-01-01

Visual receptive field (RF) attributes in visual cortex of primates have been explained mainly from cortical connections: visual RFs progress from simple to complex through cortico-cortical pathways from lower to higher levels in the visual hierarchy. This feedforward flow of information is paired with top-down processes through the feedback pathway. Although the hierarchical organization explains the spatial properties of RFs, is unclear how a non-linear transmission of activity through the visual hierarchy can yield smooth contrast response functions in all level of the hierarchy. Depending on the gain, non-linear transfer functions create either a bimodal response to contrast, or no contrast dependence of the response in the highest level of the hierarchy. One possible mechanism to regulate this transmission of visual contrast information from low to high level involves an external component that shortcuts the flow of information through the hierarchy. A candidate for this shortcut is the Pulvinar nucleus of the thalamus. To investigate representation of stimulus contrast a hierarchical model network of ten cortical areas is examined. In each level of the network, the activity from the previous layer is integrated and then non-linearly transmitted to the next level. The arrangement of interactions creates a gradient from simple to complex RFs of increasing size as one moves from lower to higher cortical levels. The visual input is modeled as a Gaussian random input, whose width codes for the contrast. This input is applied to the first area. The output activity ratio among different contrast values is analyzed for the last level to observe sensitivity to a contrast and contrast invariant tuning. For a purely cortical system, the output of the last area can be approximately contrast invariant, but the sensitivity to contrast is poor. To account for an alternative visual processing pathway, non-reciprocal connections from and to a parallel pulvinar like structure of nine areas is coupled to the system. Compared to the pure feedforward model, cortico-pulvino-cortical output presents much more sensitivity to contrast and has a similar level of contrast invariance of the tuning. PMID:22654750

Mechanics in the Production of Mandibular Fractures: A Clinical, Retrospective Case-Control Study

PubMed Central

Yang, Rongtao; Li, Zhi; Li, Zubing

2016-01-01

As the mandible is susceptible to fracture, the aim of this study was to use multivariate logistic regression analysis to identify and distinguish various internal factors that may influence the location of mandibular fractures. The study included 1131 patients with maxillofacial fractures during the period from January 2000 to December 2009 to evaluate the association of mandibular fracture location (unilateral symphysis, body, angle, condylar, or bilateral condylar fractures) with various internal factors. Among the 1131 patients, 869 had mandibular fractures. Data on age, sex, soft tissue injuries, dental trauma, and maxillofacial fracture type were collected and analyzed using multivariate logistic regression. In total, 387, 210, 139, 319, and 172 patients were diagnosed with unilateral symphysis, body, angle, unilateral, or bilateral condylar fractures, respectively. The dental trauma in patients with bilateral condylar fractures differed from that in patients with unilateral condylar fractures. Patients with mandibular fracture (unilateral symphysis, body, unilateral or bilateral condylar) possessed an approximately equal risk of soft tissue injuries in the mandible. Patients with either unilateral or bilateral condylar fractures were associated with a low risk of mandibular angle fracture (OR < 1). Similarly, patients with mandibular angle fracture were associated with a low risk of unilateral or bilateral condylar fractures (OR < 1). Moreover, patients with symphysis fracture were associated with a low risk of bilateral condylar fractures (90 of 387 [23.3%], OR 0.899). By contrast, patients with bilateral condylar fractures were associated with a high risk of symphysis fracture (90 of 172 [52.3%], OR 17.38). Patients with condylar fractures, particularly those with bilateral condylar fractures, were infrequently associated with secondary mandibular fractures. Mandibular fractures tended to have less of an association with midfacial fractures. The occurrence of mandibular fractures is strongly correlated with age, sex, soft tissue injuries, dental trauma, and the pattern and position of the maxillofacial fractures in patients. PMID:26900699

The pediatric mandible: I. A primer on growth and development.

PubMed

Smartt, James M; Low, David W; Bartlett, Scott P

2005-07-01

After studying this article, the participant should be able to: 1. Describe embryonic and fetal mandibular development. 2. Summarize the aggregate changes in mandibular form from birth to puberty. 3. Describe the eruption and maturation of the deciduous and permanent mandibular dentition. In this, the first of two articles addressing the surgical management of pediatric mandibular fractures, the authors provide a detailed discussion of mandibular development and anatomy during the fetal period, infancy, and childhood. A review of the pertinent literature was performed. The changing structure of the developing mandible is discussed, with particular attention to surgically relevant anatomical structures. Throughout development, key anatomical structures with relevance to surgical therapy change markedly in position. The mandible undergoes significant change in its bony structure and the composition of its surrounding soft tissues. The mandible's bony structure becomes more robust, with an increasingly acute gonial angle and enlargement of the ramus and body. Furthermore, the mandible provides the bony structure from which tooth buds erupt as the deciduous and permanent dentition--a process that generates significant growth of the alveolar process. As a consequence, the distance between the developing dentition and the inferior mandibular border increases. While the canal of the inferior alveolar nerve undergoes significant superior displacement, the mental foramen becomes positioned more posteriorly over time. In addition, the ligamentous and muscular attachments that surround the temporomandibular joint become increasingly robust. Throughout childhood and adolescence, the blood supply of the mandibular body changes little, with the buccal periosteal plexus and inferior dental artery making significant contributions. Mandibular growth provides the basis for normal occlusal relations and the generation of increasingly large masticatory force. Although the exact mechanisms of bone remodeling during mandibular development remain unclear, the process likely receives contributions from primary growth centers and the response to local alterations in biomechanical force produced by surrounding soft-tissue structures. A working knowledge of the changing mandibular anatomy is a prerequisite for effective clinical management of traumatic injury.

Fractures Due to Gunshot Wounds: Do Retained Bullet Fragments Affect Union?

PubMed

Riehl, John T; Connolly, Keith; Haidukewych, George; Koval, Ken

2015-01-01

Many types of projectiles, including modern hollow point bullets, fragment into smaller pieces upon impact, particularly when striking bone. This study was performed to examine the effect on time to union with retained bullet material near a fracture site in cases of gunshot injury. All gunshot injuries operatively treated with internal fixation at a Level 1 Trauma Center between March 2008 and August 2011 were retrospectively reviewed. Retained bullet load near the fracture site was calculated based on percentage of material retained compared to the cortical diameter of the involved bone. Analyses were performed to assess the effect of the lead-cortical ratio and amount of comminution on time to fracture union. Thirty-two patients (34 fractures) met the inclusion criteria, with an equal number of comminuted (17) and non-comminuted fractures (17). Seventeen of 34 fractures (50%) united within 4 months, 16/34 (47%) developed a delayed union, and 1/34 (3%) developed a nonunion requiring revision surgery. Sixteen of 17 fractures (94%) that united by 4 months had a cumulative amount of bullet fragmentation retained near the fracture site of less than 20% of the cortical diameter. Nine out of 10 fractures (90%) with retained fragments near the fracture site was equal to or exceeding 20% of the cortical diameter had delayed or nonunion. Fracture comminution had no effect on time to union. The quantity of retained bullet material near the fracture site was more predictive of the rate of fracture union than was comminution. Fractures with bullet fragmentation equal to or exceeding 20% of the cortical width demonstrated a significantly higher rate of delayed union/nonunion compared to those fractures with less retained bullet material, which may indicate a local cytotoxic effect from lead on bone healing. These findings may influence decisions on timing of secondary surgeries. Level III.

Fractures Due to Gunshot Wounds: Do Retained Bullet Fragments Affect Union?

PubMed Central

Riehl, John T.; Connolly, Keith; Haidukewych, George; Koval, Ken

2015-01-01

Background Many types of projectiles, including modern hollow point bullets, fragment into smaller pieces upon impact, particularly when striking bone. This study was performed to examine the effect on time to union with retained bullet material near a fracture site in cases of gunshot injury. Methods All gunshot injuries operatively treated with internal fixation at a Level 1 Trauma Center between March 2008 and August 2011 were retrospectively reviewed. Retained bullet load near the fracture site was calculated based on percentage of material retained compared to the cortical diameter of the involved bone. Analyses were performed to assess the effect of the lead-cortical ratio and amount of comminution on time to fracture union. Results Thirty-two patients (34 fractures) met the inclusion criteria, with an equal number of comminuted (17) and non-comminuted fractures (17). Seventeen of 34 fractures (50%) united within 4 months, 16/34 (47%) developed a delayed union, and 1/34 (3%) developed a nonunion requiring revision surgery. Sixteen of 17 fractures (94%) that united by 4 months had a cumulative amount of bullet fragmentation retained near the fracture site of less than 20% of the cortical diameter. Nine out of 10 fractures (90%) with retained fragments near the fracture site was equal to or exceeding 20% of the cortical diameter had delayed or nonunion. Fracture comminution had no effect on time to union. Conclusions The quantity of retained bullet material near the fracture site was more predictive of the rate of fracture union than was comminution. Fractures with bullet fragmentation equal to or exceeding 20% of the cortical width demonstrated a significantly higher rate of delayed union/nonunion compared to those fractures with less retained bullet material, which may indicate a local cytotoxic effect from lead on bone healing. These findings may influence decisions on timing of secondary surgeries. Level of Evidence Level III PMID:26361445

Lidocaine Concentration in Mandibular Bone After Subperiosteal Infiltration Anesthesia Decreases With Elevation of Periosteal Flap and Irrigation With Saline

PubMed Central

Ogawa, Sachie; Watanabe, Masahiro; Kawaai, Hiroyoshi; Tada, Hitoshi; Yamazaki, Shinya

2014-01-01

It has been reported that the action of infiltration anesthesia on the jawbone is attenuated significantly by elevation of the periosteal flap with saline irrigation in clinical studies; however, the reason is unclear. Therefore, the lidocaine concentration in mandibular bone after subperiosteal infiltration anesthesia was measured under several surgical conditions. The subjects were 48 rabbits. Infiltration anesthesia by 0.5 mL of 2% lidocaine with 1 : 80,000 epinephrine (adrenaline) was injected into the right mandibular angle and left mandibular body, respectively. Under several surgical conditions (presence or absence of periosteal flap, and presence or absence of saline irrigation), both mandibular bone samples were removed at a fixed time after subperiosteal infiltration anesthesia. The lidocaine concentration in each mandibular bone sample was measured by high-performance liquid chromatography. As a result, elevation of the periosteal flap with saline irrigation significantly decreased the lidocaine concentration in the mandibular bone. It is suggested that the anesthetic in the bone was washed out by saline irrigation. Therefore, supplemental conduction and/or general anesthesia should be utilized for long operations that include elevation of the periosteal flap with saline irrigation. PMID:24932978

Thin-plate spline graphical analysis of the mandible in mandibular prognathism.

PubMed

Chang, Hsin-Fu; Chang, Hong-Po; Liu, Pao-Hsin; Chang, Chih-Han

2002-11-01

The chin cup has been used to treat skeletal mandibular prognathism in growing patients for 200 years. The pull on the orthopedic-force chin cup is oriented along a line from the mandibular symphysis to the mandibular condyle. Various levels of success have been reported with this restraining device. The vertical chin cup produces strong vertical compression stress on the maxillary molar regions when the direction of traction is 20 degrees more vertical than the chin-condyle line. This treatment strategy may prevent relapse due to counter-clockwise rotation of the mandible. In this report, we describe a new strategy for using chin-cup therapy involving thin-plate spline (TPS) analysis of lateral cephalometric roentgenograms to visualize transformation of the mandible. The actual sites of mandibular skeletal change are not detectable with conventional cephalometric analysis. A case of mandibular prognathism treated with a chin cup and a case of dental Class III malocclusion without orthodontic treatment are described. The case analysis illustrates that specific patterns of mandibular transformation are associated with Class III malocclusion with or without orthopedic therapy, and that visualization of these deformations is feasible using TPS graphical analysis.

Effects of bite-jumping appliances on mandibular advancement in growing rats: A radiographic study

PubMed Central

Oksayan, Ridvan; Sokucu, Oral; Ucuncu, Neslihan

2014-01-01

Objective: The aim was to evaluate the effects of the use of mandibular advancement appliances on mandibular growth in growing rats. Materials and Methods: Twenty-four 8-week-old male Wistar albino rats were randomly divided into two experimental groups (12 rats each): Group I was a control group, and Group II was the mandibular advancement appliance group. A functional bite-jumping appliance was used in Group II to promote mandibular advancement. Anatomical changes in the condyle and mandible were evaluated by comparing radiographic results from before and after the study, with angular and linear measurements. Friedman and Mann-Whitney U-tests were used in statistical analysis. Results: According to the radiographic results, the growth of mandibles and condyles in Group II was significantly greater than with the length of the condylar process (A-B) and distance from condyle to menton (A-D) variables (P < 0.05). In addition, Group I showed greater mandibular base growth than did Group II (P < 0.05). Conclusions: We conclude that the use of an intraoral bite-jumping appliance can stimulate condylar growth and increase sagittal mandibular advancement in growing rats. PMID:25202205

A two-stage rule-constrained seedless region growing approach for mandibular body segmentation in MRI.

PubMed

Ji, Dong Xu; Foong, Kelvin Weng Chiong; Ong, Sim Heng

2013-09-01

Extraction of the mandible from 3D volumetric images is frequently required for surgical planning and evaluation. Image segmentation from MRI is more complex than CT due to lower bony signal-to-noise. An automated method to extract the human mandible body shape from magnetic resonance (MR) images of the head was developed and tested. Anonymous MR images data sets of the head from 12 subjects were subjected to a two-stage rule-constrained region growing approach to derive the shape of the body of the human mandible. An initial thresholding technique was applied followed by a 3D seedless region growing algorithm to detect a large portion of the trabecular bone (TB) regions of the mandible. This stage is followed with a rule-constrained 2D segmentation of each MR axial slice to merge the remaining portions of the TB regions with lower intensity levels. The two-stage approach was replicated to detect the cortical bone (CB) regions of the mandibular body. The TB and CB regions detected from the preceding steps were merged and subjected to a series of morphological processes for completion of the mandibular body region definition. Comparisons of the accuracy of segmentation between the two-stage approach, conventional region growing method, 3D level set method, and manual segmentation were made with Jaccard index, Dice index, and mean surface distance (MSD). The mean accuracy of the proposed method is [Formula: see text] for Jaccard index, [Formula: see text] for Dice index, and [Formula: see text] mm for MSD. The mean accuracy of CRG is [Formula: see text] for Jaccard index, [Formula: see text] for Dice index, and [Formula: see text] mm for MSD. The mean accuracy of the 3D level set method is [Formula: see text] for Jaccard index, [Formula: see text] for Dice index, and [Formula: see text] mm for MSD. The proposed method shows improvement in accuracy over CRG and 3D level set. Accurate segmentation of the body of the human mandible from MR images is achieved with the proposed two-stage rule-constrained seedless region growing approach. The accuracy achieved with the two-stage approach is higher than CRG and 3D level set.

Culture-expanded mesenchymal stem cell sheets enhance extraction-site alveolar bone growth: An animal study.

PubMed

Mu, S; Tee, B C; Emam, H; Zhou, Y; Sun, Z

2018-04-06

Impaired bone formation of the buccal alveolar plate after tooth extraction during adolescence increases the difficulty of future implant restoration. This study was undertaken to assess the feasibility and efficacy of transplanting autogenous scaffold-free culture-expanded mesenchymal stem cell (MSC) sheets to the buccal alveolar bone surface to stimulate local bone growth. Mandibular bone marrow was aspirated from 3-month-old pigs (n = 5), from which MSCs were isolated and culture expanded. Triple-layer MSC sheets were then fabricated using temperature-responsive tissue culture plates. One month after bone marrow aspirations, the same pigs underwent bilateral extraction of mandibular primary molars, immediately followed by transplantation of 3 autogenous triple-layer MSC sheets on to the subperiosteal buccal alveolar surface of 1 randomly chosen side. The contralateral side (control) underwent the same periosteal reflection surgery without receiving MSC sheet transplantation. Six weeks later, the animals were killed and specimens from both sides were immediately harvested for radiographic and histological analysis. Buccal alveolar bone thickness, tissue mineral density (TMD), mineral apposition and bone volume fraction (BV/TV) were quantified and compared between the MSC sheet and control sides using paired t-tests. Triple-layer MSC sheets were reliably fabricated and the majority of cells remained vital before transplantation. The thickness of buccal bone tended to increase with MSC sheet transplantation (P = .18), with 4 of 5 animals showing an average of 1.82 ± 0.73 mm thicker bone on the MSC sheet side than the control side. After being normalized by the TMD of intracortical bone, the TMD of surface cortical bone was 0.5-fold higher on the MSC sheet side than the control side (P < .05). Likewise, the BV/TV measurements of the buccal surface region were also 0.4-fold higher on the MSC sheet side than the control side (P < .05) after being normalized by measurements from the intracortical region. Mineral apposition measurements were not different between the 2 sides. Mandibular marrow-derived MSCs can be fabricated into cell sheets and autogenous transplantation of MSC sheets onto the subperiosteal buccal alveolar bone surface at the tooth-extraction site may increase local bone density. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Anterior mandibular apical base augmentation in the surgical orthodontic treatment of mandibular retrusion.

PubMed

Brusati, R; Giannì, A B

2005-12-01

The authors describe a surgical technique alternative to traditional pre-surgical orthodontics in order to increase the apical base in mandibular retrusion (class II, division I). This subapical osteotomy, optimizing inferior incisal axis without dental extractions and a long orthodontic treatment, associated to genioplasty permits to obtain an ideal labio-dento-mental morphology. This procedure avoids in some cases the need of a mandibular advancement and, if necessary, it reduces his entity with obvious advantages.

Impaction of permanent mandibular second molar: A retrospective study

PubMed Central

Altieri, Federica; Di Mambro, Alfonso; Galluccio, Gabriella; Barbato, Ersilia

2013-01-01

Objective: To determine the prevalence of impacted mandibular second molar (MM2) and the association between MM2 impaction and crowding. The clinical significance of the angle between first and second mandibular molar and of the space between the first mandibular molar (MM1) and the anterior margin of mandibular ramus in MM2 impaction were also evaluated. Material and Methods: In this retrospective study , from the dental records of 2,945 caucasian young orthodontics patients, 40 subjects with MM2 impaction were included in a study group (SG) and compared with a control group (CG) of 200 subjects without MM2 impactions. The crowding, the angle of inclination of MM2, the distance between MM1 and mandibular ramus, the canine and molar relationships, and the lower centre line discrepancy were measured. For the statistical analysis , descriptive statistics and t-Student for independent sample groups were used. Results: The prevalence of impacted MM2 was 1.36%. The independent-Samples t-Test between SG and CG showed: the presence of crowding (P≤0.001), an higher angle values of MM2 inclination (P≤0.001) and a smaller distance between MM1 and the anterior margin of mandibular ramus (P≤0.001) in the SG. Conclusion: The impaction of MM2 is a relatively rare occurrence in orthodontic caucasian populations. The crowding, a higher angle values of MM2 inclination and a reduced distance between MM1 and the anterior margin of mandibular ramus, at the time of one third of MM2 root formation (T1), characterize MM2 impaction. Key words:Impacted mandibular second molar, impaction, orthodontics. PMID:23524438

Biology of biomechanics: Finite element analysis of a statically determinate system to rotate the occlusal plane for correction of a skeletal Class III open-bite malocclusion.

PubMed

Roberts, W Eugene; Viecilli, Rodrigo F; Chang, Chris; Katona, Thomas R; Paydar, Nasser H

2015-12-01

In the absence of adequate animal or in-vitro models, the biomechanics of human malocclusion must be studied indirectly. Finite element analysis (FEA) is emerging as a clinical technology to assist in diagnosis, treatment planning, and retrospective analysis. The hypothesis tested is that instantaneous FEA can retrospectively simulate long-term mandibular arch retraction and occlusal plane rotation for the correction of a skeletal Class III malocclusion. Seventeen published case reports were selected of patients treated with statically determinate mechanics using posterior mandible or infrazygomatic crest bone screw anchorage to retract the mandibular arch. Two-dimensional measurements were made for incisor and molar movements, mandibular arch rotation, and retraction relative to the maxillary arch. A patient with cone-beam computed tomography imaging was selected for a retrospective FEA. The mean age for the sample was 23.3 ± 3.3 years; there were 7 men and 10 women. Mean incisor movements were 3.35 ± 1.55 mm of retraction and 2.18 ± 2.51 mm of extrusion. Corresponding molar movements were retractions of 4.85 ± 1.78 mm and intrusions of 0.85 ± 2.22 mm. Retraction of the mandibular arch relative to the maxillary arch was 4.88 ± 1.41 mm. Mean posterior rotation of the mandibular arch was -5.76° ± 4.77° (counterclockwise). The mean treatment time (n = 16) was 36.2 ± 15.3 months. Bone screws in the posterior mandibular region were more efficient for intruding molars and decreasing the vertical dimension of the occlusion to close an open bite. The full-cusp, skeletal Class III patient selected for FEA was treated to an American Board of Orthodontics Cast-Radiograph Evaluation score of 24 points in about 36 months by en-masse retraction and posterior rotation of the mandibular arch: the bilateral load on the mandibular segment was about 200 cN. The mandibular arch was retracted by about 5 mm, posterior rotation was about 16.5°, and molar intrusion was about 3 mm. There was a 4° decrease in the mandibular plane angle to close the skeletal open bite. Retrospective sequential iterations (FEA animation) simulated the clinical response, as documented with longitudinal cephalometrics. The level of periodontal ligament stress was relatively uniform (<5 kPa) for all teeth in the mandibular arch segment. En-masse retraction of the mandibular arch is efficient for conservatively treating a skeletal Class III malocclusion. Posterior mandibular anchorage causes intrusion of the molars to close the vertical dimension of the occlusion and the mandibular plane angle. Instantaneous FEA as modeled here could be used to reasonably predict the clinical results of an applied load. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

A Simplified Way for the Stabilization of Pediatric Mandibular Fracture With an Occlusal Splint.

PubMed

Demirkol, Mehmet; Demirkol, Nermin; Abdo, Omar Hasan; Aras, Mutan Hamdi

2016-06-01

The management of pediatric mandibular fractures is challenging for maxillofacial surgeons due to ongoing mandibular growth involving tooth buds. The treatment of such fractures has been a topic of much research. Generally accepted methods for the treatment of mandibular parasymphyseal or symphyseal fractures in children are conservative approaches involving the use of acrylic splints, lateral compression with an open-cap splint stabilized by circummandibular wiring, and maxillomandibular fixation with an arch bar and eyelet wiring. The aim of this technical note was to describe a straightforward approach to the treatment of pediatric mandibular fractures, in which an occlusal splint is secured to prevent trauma to the soft tissue, without the need for general anesthesia.

Pediatric mandibular fractures treated by rigid internal fixation.

PubMed

Wong, G B

1993-09-01

Mandibular fractures in the pediatric patient population are relatively uncommon. These patients present with their own unique treatment requirements. Most fractures have been treated conservatively by dental splints. Closed reduction techniques with maxillomandibular fixation (MMF) in very young children can pose several concerns, including cooperation, compliance and adequate nutritional intake. Rigid internal fixation of unstable mandibular fractures using miniplates and screws circumvents the need for MMF and allows immediate jaw mobilization. At major pediatric trauma institutions, there has been an increasing trend toward the use of this treatment when open reduction is necessary. This article presents a report of a five-year-old child who presented with bilateral mandibular fractures and was treated by rigid internal fixation and immediate mandibular mobilization.

Influence of mandibular morphology on the hyoid bone in atypical deglutition: a correlational study.

PubMed

Machado, Almiro J; Crespo, Agrício N

2011-11-01

evaluate the possible correlation with the radiographic position of the hyoid bone and mandibular angle in lateral radiographs of children with atypical deglutition. This was an observational study using cephalometric analysis of lateral teleradiographs for the distances of H-MP (hyoid to mandibular plane). Spearman's correlation analysis was performed with MA (mandibular angle) in two groups: the experimental group with atypical deglutition and the control group normal deglutition. Both groups included subjects in mixed dentition stage. there was a significant moderate negative correlation between MA (mandibular angle) and hyoid bone (H-MP) in the normal group (R = -0.406, p = 0.021). However, there was no significant correlation between the MA and H-MP (R = 0.029, p = 0.83) in the group with atypical deglutition. there is a moderate negative correlation between the position of the hyoid bone and mandibular angle in the group of normal swallowing and there is no correlation between variables H-MP and MA in the group of atypical swallowing.

Mandibular growth changes and cervical vertebral maturation. a cephalometric implant study.

PubMed

Gu, Yan; McNamara, James A

2007-11-01

To evaluate mandibular dimensional changes and regional remodeling occurring during five intervals of circumpubertal growth. This investigation evaluated a unique sample of subjects in whom tantalum implants were placed into the craniofacial complex during childhood. The sample was obtained from the Mathews and Ware implant study originally conducted at the University of California San Francisco in the 1970s, with longitudinal cephalometric records of 20 subjects (13 female, 7 male) available for evaluation. Cephalograms at six consecutive stages of cervical vertebral maturation (CS1 through CS6) were analyzed. Peak mandibular growth was noted during the interval from CS3 to CS4. Forward rotation of the mandible was due to greater mandibular growth posteriorly than anteriorly. Progressive closure of the condylar-ramus-occlusal (CRO) angle resulted in a forward and upward orientation of the ramus relative to the corpus of the mandible due to increased vertical growth of the condyle. A peak in mandibular growth at puberty was substantiated. Mandibular remodeling and condylar rotation continue to occur after the growth spurt.

[Stress analysis of the mandible by 3D FEA in normal human being under three loading conditions].

PubMed

Sun, Jian; Zhang, Fu-qiang; Wang, Dong-wei; Yu, Jia; Wang, Cheng-tao

2004-02-01

The condition and character of stress distribution in the mandibular in normal human being during centric, protrusive, laterotrusive occlusion were analysed. The three-dimensional finite element model of the mandibular was developed by helica CT scanning and CAD/CAM software, and three-dimensional finite element stress analysis was done by ANSYS software. Three-dimensional finite element model of the mandibular was generated. Under these three occlusal conditions, the stress of various regions in the mandible were distributed unequally, and the stress feature was different;while the stress of corresponding region in bilateral mandibular was in symmetric distribution. The stress value of condyle neck, the posterior surface of coronoid process and mandibular angle were high. The material properties of mandible were closely correlated to the value of stress. Stress distribution were similar according to the three different loading patterns, but had different effects on TMJ joint. The concentrated areas of stress were in the condyle neck, the posterior surface of coronoid process and mandibular angle.

Craniofacial morphometric analysis of mandibular prognathism.

PubMed

Chang, H P; Liu, P H; Yang, Y H; Lin, H C; Chang, C H

2006-03-01

The purpose of this study was to provide more information about the morphological characteristics of the craniofacial complex in mandibular prognathism. Forty young adult males having mandibular prognathism were compared with 40 having normal occlusion. This was conducted to carry out geometric morphometric assessments to localize alterations, using Procrustes analysis and thin-plate spline analysis, in addition to conventional cephalometric techniques. Procrustes analysis indicated that the mean craniofacial, midfacial and mandibular morphology was significantly different in prognathic subjects compared with normal controls. This finding was corroborated by the multivariate Hotelling T(2)-test of cephalometric variables. Mandibular prognathism demonstrated a shorter and slightly retropositioned maxilla, a greater total length and anterior positioning of the mandible. Thin-plate spline analysis revealed a developmental diminution of the palatomaxillary region anteroposteriorly and a developmental elongation of the mandible anteroposteriorly, leading to the appearance of a prognathic mandibular profile. In conclusion, thin-plate spline analysis seems to provide a valuable supplement for conventional cephalometric analysis because the complex patterns of craniofacial shape change are visualized suggestive by means of grid deformations.

Intraoperative monitoring of marginal mandibular nerve during neck dissection.

PubMed

Tirelli, Giancarlo; Bergamini, Pier Riccardo; Scardoni, Alessandro; Gatto, Annalisa; Boscolo Nata, Francesca; Marcuzzo, Alberto Vito

2018-05-01

The purpose of this study was to assess the efficacy of intraoperative nerve integrity monitoring (NIM) to prevent marginal mandibular nerve injuries during neck dissection. This prospective study compared 36 patients undergoing NIM-assisted neck dissection from July 2014 to March 2015 to a cohort of 35 patients subjected to neck dissection over an identical period of time before the technique was introduced. We also assessed possible correlations between marginal mandibular nerve injuries and other factors, such as anthropometric measurements, presence of clinical neck metastases, type of neck dissection, and site of primary tumor. The incidence of marginal mandibular nerve paralyses was significantly lower among the group of patients undergoing NIM-assisted neck dissection (P = .021). There was no significant difference in the duration of the procedure, and the technique resulted in a limited increase of cost. No other factor seemed to influence the onset of marginal mandibular nerve palsy. In our opinion, NIM is a valuable aid for preventing marginal mandibular nerve injuries during neck dissection. © 2018 Wiley Periodicals, Inc.

[Maxillo-facial surgery in skeletal Class II: repercussions on the temporo-mandibular joints].

PubMed

Manière-Ezvan, Armelle; Savoldelli, Charles; Busson, Floriant; Oueiss, Arlette; Orthlieb, Jean-Daniel

2016-03-01

These interventions usually aimed at the correction of the skeletal discrepancy by mandibular retrognatism with an advancement of the distal portion of the mandible after mandibular osteotomy. The position of the condyle is determined during the osteosynthesis with miniplates. Condyles are set back in relation with the supine position of the patient and the weakness of his (her) curarized muscle. All studies show that surgery of mandibular advancement causes a lateral, torque and backward movement of the condyles, all harmful to the condyles. Factors that predispose to condylar resorption are "the patient": a woman, young (between 15 and 40), high mandibular angle, with a history of temporo-mandibular disorders and surgical overload applied to the condyles. What are the possible solutions to avoid failures? Patient preparation before surgery and surgery simulation with an articulator, condylar position control during surgery, working with surgeons to achieve a condylar portion stabilization system (with the CAD), quickly set up a mobilization of the mandible by physiotherapy. © EDP Sciences, SFODF, 2016.

Content Validity of Temporal Bone Models Printed Via Inexpensive Methods and Materials.

PubMed

Bone, T Michael; Mowry, Sarah E

2016-09-01

Computed tomographic (CT) scans of the 3-D printed temporal bone models will be within 15% accuracy of the CT scans of the cadaveric temporal bones. Previous studies have evaluated the face validity of 3-D-printed temporal bone models designed to train otolaryngology residents. The purpose of the study was to determine the content validity of temporal bone models printed using inexpensive printers and materials. Four cadaveric temporal bones were randomly selected and clinical temporal bone CT scans were obtained. Models were generated using previously described methods in acrylonitrile butadiene styrene (ABS) plastic using the Makerbot Replicator 2× and Hyrel printers. Models were radiographically scanned using the same protocol as the cadaveric bones. Four images from each cadaveric CT series and four corresponding images from the model CT series were selected, and voxel values were normalized to black or white. Scan slices were compared using PixelDiff software. Gross anatomic structures were evaluated in the model scans by four board certified otolaryngologists on a 4-point scale. Mean pixel difference between the cadaver and model scans was 14.25 ± 2.30% at the four selected CT slices. Mean cortical bone width difference and mean external auditory canal width difference were 0.58 ± 0.66 mm and 0.55 ± 0.46 mm, respectively. Expert raters felt the mastoid air cells were well represented (2.5 ± 0.5), while middle ear and otic capsule structures were not accurately rendered (all averaged <1.8). These results suggest that these models would be sufficient adjuncts to cadaver temporal bones for training residents in cortical mastoidectomies, but less effective for middle ear procedures.

Localization and pattern of graviresponse across the pulvinus of barley Hordeum vulgare

NASA Technical Reports Server (NTRS)

Brock, T. G.; Lu, C. R.; Ghosheh, N. S.; Kaufman, P. B.

1989-01-01

Pulvini of excised stem segments from barley (Hordeum vulgare cv Larker') were pretreated with 1 millimolar coumarin before gravistimulation to reduce longitudinal cell expansion and exaggerate radial cell enlargement. The cellular localization and pattern of graviresponse across individual pulvini were then evaluated by cutting the organ in cross-section, photographing the cross-section, and then measuring pulvinus thickness and the radial width of cortical and epidermal cells in enlargements of the photomicrographs. With respect to orientation during gravistimulation, we designated the uppermost point of the cross-section 0 degrees and the lowermost point 180 degrees. A gravity-induced increase in pulvinus thickness was observable within 40 degrees of the vertical in coumarin-treated pulvini. In upper halves of coumarin-treated gravistimulated pulvini, cells in the inner cortex and inner epidermis had increased radial widths, relative to untreated gravistimulated pulvini. In lower halves of coumarin-treated pulvini, cells in the central and outer cortex and in the outer epidermis showed the greatest increase in radial width. Cells comprising the vascular bundles also increased in radial width, with this pattern following that of the central cortex. These results indicate (a) that all cell types are capable of showing a graviresponse, (b) that the graviresponse occurs in both the top and the bottom of the responding organ, and (c) that the magnitude of the response increases approximately linearly from the uppermost point to the lowermost. These results are also consistent with models of gravitropism that link the pattern and magnitude of the graviresponse to graviperception via statolith sedimentation.

Skeletal maturity assessment using mandibular canine calcification stages.

PubMed

Džemidžić, Vildana; Tiro, Alisa; Zukanović, Amila; Redžić, Ismeta; Nakaš, Enita

2016-11-01

The aims of this study were: to investigate the relationship between mandibular canine calcification stages and skeletal maturity; and to evaluate whether the mandibular canine calcification stages may be used as a reliable diagnostic tool for skeletal maturity assessment. This study included 151 subjects: 81 females and 70 males, with ages ranging from 9 to 16 years (mean age: 12.29±1.86 years). The inclusion criteria for subjects were as follows: age between 9 and 16 years; good general health without any hormonal, nutritional, growth or dental development problems. Subjects who were undergoing or had previously received orthodontic treatment were not included in this study. The calcification stages of the left permanent mandibular canine were assessed according to the method of Demirjian, on panoramic radiographs. Assessment of skeletal maturity was carried out using the cervical vertebral maturation index (CVMI), as proposed by the Hassel-Farman method, on lateral cephalograms. The correlation between the calcification stages of mandibular canine and skeletal maturity was estimated separately for male and female subjects. Correlation coefficients between calcification stages of mandibular canine and skeletal maturity were 0.895 for male and 0.701 for female subjects. A significant correlation was found between the calcification stages of the mandibular canine and skeletal maturity. The calcification stages of the mandibular canine show a satisfactory diagnostic performance only for assessment of pre-pubertal growth phase. Copyright © 2016 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Stress analysis at bone-implant interface of single- and two-implant-retained mandibular overdenture using three-dimensional finite element analysis.

PubMed

Lahoti, Krishnakumar; Pathrabe, Anup; Gade, Jaykumar

2016-01-01

The purpose of this research was to compare stress distribution on the bone between single implant-retained and two-implant-retained mandibular overdentures using three-dimensional (3D) finite element analysis. Two 3D finite element models were designed. The first model included single implant-supported mandibular overdenture placed in the midline of the mandible while the second model included two-implant-supported mandibular overdenture placed in the intra-foramen region, retained by ball attachment of the same diameter. The bone was modeled on the D2 bone depending on the classification given by Misch. A computed tomography scan of the mandible was used to model the bone by plotting the key points on the graph and generating the identical key points on the ANSYS Software (ANSYS, Inc., USA). The implant was modeled using appropriate dimensions as provided by the manufacturer. Stresses were calculated based on the von Mises criteria. Stresses produced in the hard bone (HB) and soft bone (SB) were higher in single implant-retained mandibular overdenture while stresses produced around the denture as well as implant were higher in two-implant-retained mandibular overdenture. Within the limitations of the study, it had been seen that stresses produced were the highest on HB and SB in single implant-retained mandibular overdenture while stresses produced across the denture as well as implant were the highest in two-implant-retained mandibular overdenture.

Assessment of Growth Using Mandibular Canine Calcification Stages and Its Correlation with Modified MP3 Stages.

PubMed

Nayak, Reshma; Nayak, Us Krishna; Hegde, Gautam

2010-01-01

Orthodontic diagnosis and treatment planning for growing children must involve growth prediction, especially in the treatment of skeletal problems. Studies have shown that a strong association exists between skeletal maturity and dental calcification stages. The present study was therefore taken up to provide a simple and practical method for assessing skeletal maturity using a dental periapical film and standard dental X-ray machine, to compare the developmental stages of the mandibular canine with that of developmental stages of modified MP3 and to find out if any correlation exists, to determine if the developmental stages of the mandibular canine alone can be used as a reliable indicator for assessment of skeletal maturity. A total of 160 periapical radiographs (80 males and 80 females), of the mandibular right canine and the MP3 region was taken and assessed according to the Dermirjian's stages of dental calcification and the modified MP3 stages. The correlation between the developmental stages of MP3 and the mandibular right canine in male and female groups, is of high statistical significance (p = 0.001). The correlation coefficient between MP3 stages and developmental stages of mandibular canine and chronological age in male and females was found to be not significant. The correlation between the mandibular canine calcification stages and MP3 stages was found to be significant. The developmental stages of the mandibular canine could be used very reliably as a sole indicator for assessment of skeletal maturity.

Association between eruption state of the third molar and the occurrence of mandibular angle fractures.

PubMed

Rahimi-Nedjat, Roman K; Sagheb, Keyvan; Jacobs, Collin; Walter, Christian

2016-10-01

Fractures of the mandible, especially the mandibular angle, are one of the most frequent types of injuries of the facial skeleton. In many cases, a retained third molar can be found in the line of the fracture. However, it remains unclear whether a relationship between third molars and mandibular angle fractures exists. Patients with isolated or combined fractures of the lower jaw between January 2001 and December 2007 were analyzed retrospectively. Electronic health records were investigated regarding the types of mandibular fractures, and panoramic radiographs were reviewed concerning the existence of third molars. In addition, a systematic review was performed to compare the findings of this study with existing data. Six hundred and thirty-two patients were treated for mandibular fractures within the time frame. Two hundred and sixty-seven had a mandibular angle fracture. In 461 patients, panoramic radiographs were available, of which 45.6% did not have a third molar. About 3.8% were edentulous. There is a significant relationship between the existence of unerupted third molars and the occurrence of mandibular angle fractures (P < 0.001). No correlation exists for erupted third molars. Fractures of the mandibular angle are more likely to appear in patients with retained third molars which might be due to the reduced bone mass. Once the wisdom teeth have erupted, the bone structure is more solid and more resistant to external forces and the development of fractures. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Maxillary-driven simultaneous maxillo-mandibular distraction for hemifacial microsomia.

PubMed

Nakajima, Hideo; Sakamoto, Yoshiaki; Tamada, Ikkei; Ogata, Hisao; Kishi, Kazuo; Sakamoto, Teruo

2011-12-01

We treat hemifacial microsomia with a combination of surgery and orthodontic treatment during the growth period, resulting in early improvement in facial asymmetry and the induction of normal growth. We previously used gradual distraction of the mandibular ramus for Pruzansky's type II classification (Pruzansky, 1969). In type II cases, the maxilla should also be treated actively as, using this technique, improvement of the occlusal plane is difficult to achieve, resulting in a cross bite and difficulties in post-operative orthodontic treatment-especially in older patients. Morphologically, the mandibular angle region of the operative side is flat, and the angle of the mouth remains elevated. We performed mandibular-driven simultaneous maxillo-mandibular distraction while the occlusion was maintained using intermaxillary anchorage. However, mandibular-driven distraction tended to elongate the face because the mandible only elongated downwards and the mandibular ramus did not reach the glenoid. Furthermore, external distraction devices produce significant distress for patients until removal of the device and cause scars on the face. We developed a new internal distraction device with a variable angle and performed maxillary-driven simultaneous maxillo-mandibular distraction using this device. The result was morphologically satisfactory and solved the above problems. Because the patient was in the growth period, careful follow-up and induction to normal growth were important while the inferior growth of the affected side was monitored. Copyright © 2010 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

High-frequency cortical subdural stimulation enhanced plasticity in surgery of a tumor in Broca's area.

PubMed

Barcia, Juan A; Sanz, Ana; Balugo, Paloma; Alonso-Lera, Pedro; Brin, Juan Raúl; Yus, Miguel; Gonzalez-Hidalgo, Mercedes; Acedo, Victoria M; Oliviero, Antonio

2012-03-28

Functional areas located near or within brain gliomas prevent the complete resection of these tumors. It has recently been described that slow tumor invasion promotes neural reorganization, and even topographic plasticity, allowing a staged resection of those tumors. Thus, our aim was to promote plasticity by mimicking the tumor's capability to displace brain function. This proceeded through the production of a 'virtual lesion' in eloquent areas within a tumor using continuous high-frequency cortical electrical stimulation (cHFCS). An anaplastic astrocytoma located in Broca's area progressed in a patient whose lateralization of language to the side of the lesion was demonstrated with functional MRI. After partial tumor resection using awake cortical monitoring, we implanted a subdural grid over the eloquent cortex located within residual tumor. We then applied cHFCS for 25 days, using a frequency of 130 Hz and a pulse width of 1 ms. Stimulus intensity was set to the threshold wherein mild speech disturbance was evident without any other neurological effects. This treatment successfully achieved the displacement of speech functions, and a more radical resection of the tumor was possible in a second surgery. Critically, a reorganization of motor language areas was demonstrated both with functional MRI and cortical stimulation. Furthermore, motor language areas were also identified in the right hemisphere, where previously they were absent. The patient's speech fluency improved both after stimulation and resection. We therefore demonstrate the first evidence of induced topographic plasticity using cHFCS in eloquent areas within a tumor, which allowed for increased tumor removal. Our results open the possibility to induce plasticity before the resection of brain tumors near eloquent areas, in order to increase the extent of resection.

HttQ111/+ Huntington’s Disease Knock-in Mice Exhibit Brain Region-Specific Morphological Changes and Synaptic Dysfunction

PubMed Central

Kovalenko, Marina; Milnerwood, Austen; Giordano, James; St. Claire, Jason; Guide, Jolene R.; Stromberg, Mary; Gillis, Tammy; Sapp, Ellen; DiFiglia, Marian; MacDonald, Marcy E.; Carroll, Jeffrey B.; Lee, Jong-Min; Tappan, Susan; Raymond, Lynn; Wheeler, Vanessa C.

2018-01-01

Background: Successful disease-modifying therapy for Huntington’s disease (HD) will require therapeutic intervention early in the pathogenic process. Achieving this goal requires identifying phenotypes that are proximal to the HTT CAG repeat expansion. Objective: To use Htt CAG knock-in mice, precise genetic replicas of the HTT mutation in patients, as models to study proximal disease events. Methods: Using cohorts of B6J.HttQ111/+ mice from 2 to 18 months of age, we analyzed pathological markers, including immunohistochemistry, brain regional volumes and cortical thickness, CAG instability, electron microscopy of striatal synapses, and acute slice electrophysiology to record glutamatergic transmission at striatal synapses. We also incorporated a diet perturbation paradigm for some of these analyses. Results: B6J.HttQ111/+ mice did not exhibit significant neurodegeneration or gliosis but revealed decreased striatal DARPP-32 as well as subtle but regional-specific changes in brain volumes and cortical thickness that parallel those in HD patients. Ultrastructural analyses of the striatum showed reduced synapse density, increased postsynaptic density thickness and increased synaptic cleft width. Acute slice electrophysiology showed alterations in spontaneous AMPA receptor-mediated postsynaptic currents, evoked NMDA receptor-mediated excitatory postsynaptic currents, and elevated extrasynaptic NMDA currents. Diet influenced cortical thickness, but did not impact somatic CAG expansion, nor did it show any significant interaction with genotype on immunohistochemical, brain volume or cortical thickness measures. Conclusions: These data show that a single HttQ111 allele is sufficient to elicit brain region-specific morphological changes and early neuronal dysfunction, highlighting an insidious disease process already apparent in the first few months of life. PMID:29480209

Symbiotic Fungi Control Plant Root Cortex Development through the Novel GRAS Transcription Factor MIG1.

PubMed

Heck, Carolin; Kuhn, Hannah; Heidt, Sven; Walter, Stefanie; Rieger, Nina; Requena, Natalia

2016-10-24

In an approaching scenario of soil nutrient depletion, root association with soil microorganisms can be key for plant health and sustainability [1-3]. Symbiotic arbuscular mycorrhizal (AM) fungi are major players in helping plants growing under nutrient starvation conditions. They provide plants with minerals like phosphate and, furthermore, act as modulators of plant growth altering the root developmental program [4, 5]. However, the precise mechanisms involved in this latter process are not well understood. Here, we show that AM fungi are able to modulate root cortex development in Medicago truncatula by activating a novel GRAS-domain transcription factor, MIG1, that determines the size of cortical root cells. MIG1 expression peaks in arbuscule-containing cells, suggesting a role in cell remodeling during fungal accommodation. Roots ectopically expressing MIG1 become thicker due to an increase in the number and width of cortical cells. This phenotype is fully counteracted by gibberellin (GA) and phenocopied with a GA biosynthesis inhibitor or by expression of a dominant DELLA (Δ18DELLA1) protein. MIG1 downregulation leads to malformed arbuscules, a phenotype rescued by Δ18DELLA1, suggesting that MIG1 intersects with the GA signaling to control cell morphogenesis through DELLA1. DELLA1 was shown to be a central node controlling arbuscule branching [6-8]. Now we provide evidence that, together with MIG1, DELLA1 is responsible for radial cortical cell expansion during arbuscule development. Our data point toward DELLA proteins being not only longitudinal root growth repressors [9] but also positive regulators of cortical radial cell expansion, extending the knowledge of how DELLAs control root growth. Copyright © 2016 Elsevier Ltd. All rights reserved.

21 CFR 872.3960 - Mandibular condyle prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Mandibular condyle prosthesis. 872.3960 Section 872.3960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3960 Mandibular condyle prosthesis. (a...

Development of a Mandibular Motion Simulator for Total Joint Replacement

PubMed Central

Celebi, Nukhet; Rohner, E. Carlos; Gateno, Jaime; Noble, Philip C.; Ismaily, Sabir K.; Teichgraeber, John F.; Xia, James J.

2015-01-01

Purpose The purpose of this study was to develop a motion simulator capable of recreating and recording the full range of mandibular motions in a cadaveric preparation for an intact temporomandibular joint (TMJ) and after total joint replacement. Material and Methods A human cadaver head was used. Two sets of tracking balls were attached to the forehead and mandible, respectively. Computed tomographic (CT) scan was performed and 3-dimensional CT models of the skull were generated. The cadaver head was then dissected to attach the muscle activation cables and mounted onto the TMJ simulator. Realistic jaw motions were generated through the application of the following muscle forces: lateral pterygoid muscle, suprahyoid depressors (geniohyoid, mylohyoid, and digastric muscles), and elevator muscles. To simulate muscle contraction, cables were inserted into the mandible at the center area of each muscle's attachment. To provide a minimum mouth closing force at the initial position, the elevator muscles were combined at the anterior mandible. During mandibular movement, each motion was recorded using a high-resolution laser scanner. The right TMJ of the same head was reconstructed with a total TMJ prosthesis. The same forces were applied and the jaw motions were recorded again. CT scan was performed and 3-dimensional CT models of the skull with TMJ prosthesis were generated. Results Mandibular motions, before and after TMJ replacement, with and without lateral pterygoid muscle reattachment, were re-created in a cadaveric preparation. The laser-scanned data during the mandibular motion were used to drive 3-dimensional CT models. A movie for each mandibular motion was subsequently created for motion path analysis. Compared with mandibular motion before TMJ replacement, mandibular lateral and protrusive motions after TMJ replacement, with and without lateral pterygoid muscle reattachment, were greatly limited. The jaw motion recorded before total joint replacement was applied to the mandibular and prostheses models after total TMJ replacement. The condylar component was observed sinking into the fossa during jaw motion. Conclusion A motion simulator capable of re-creating and recording full range of mandibular motions in a cadaveric preparation has been developed. It can be used to simulate mandibular motions for the intact TMJ and total joint prosthesis, and to re-create and record their full range of mandibular motions. In addition, the full range of the recorded motion can be re-created as motion images in a computer. These images can be used for motion path analysis and to study the causation of limited range of motion after total joint replacement and strategies for improvement. PMID:21050636

Bilateral bifid mandibular canal

PubMed Central

Sheikhi, Mahnaz; Badrian, Hamid; Ghorbanizadeh, Sajad

2012-01-01

One of the normal interesting variations that we may encounter in the mandible is bifid mandibular canal. This condition can lead to difficulties when performing mandibular anesthesia or during extraction of lower third molar, placement of implants, and surgery in the mandible. Therefore diagnosis of this variation is sometimes very important and necessary. PMID:23814555

21 CFR 874.3695 - Mandibular implant facial prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mandibular implant facial prosthesis. 874.3695 Section 874.3695 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... intended to be implanted for use in the functional reconstruction of mandibular deficits. The device is...

21 CFR 874.3695 - Mandibular implant facial prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Mandibular implant facial prosthesis. 874.3695 Section 874.3695 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... intended to be implanted for use in the functional reconstruction of mandibular deficits. The device is...

Prevalence of Extra Roots in Permanent Mandibular First Molars in Iranian Population: A CBCT Analysis.

PubMed

Rahimi, Saeed; Mokhtari, Hadi; Ranjkesh, Bahram; Johari, Masoomeh; Frough Reyhani, Mohammad; Shahi, Shahriar; Seif Reyhani, Sina

2017-01-01

Having knowledge about the anatomy of root canal system is essential for success of endodontic treatment. The present study used cone-beam computed tomography (CBCT), to evaluate the prevalence of third root in mandibular first molars in a selected Iranian population. A total of 386 CBCT images from subjects referred to oral and maxillofacial radiology department of dental faculty of Tabriz University of Medical Sciences from 2011 to 2013 were selected and evaluated for this study and the cases with well-developed permanent mandibular first molars were included. The 3D images were reconstructed in axial cross sections and evaluated by two endodontists for the presence of the third extra lingual (radix entomolaris) or buccal (radix paramolaris) root. The chi-squared test was used to evaluate the relationship between gender and bilateral incidence of extra roots in mandibular first molars. The distribution of three-rooted mandibular first molars with an additional root was 3%, (3.53% in female and 2.50% in male patients). There was no significant relationship between gender and bilateral occurrence of three-rooted mandibular first molars. The occurrence of three-rooted mandibular first molars in Iranian population is not uncommon which should be taken into consideration by the dental practitioners during root canal treatment of these teeth.

Combined use of rapid-prototyping model and surgical guide in correction of mandibular asymmetry malformation patients with normal occlusal relationship.

PubMed

Xu, Haisong; Zhang, Ce; Shim, Yoong Hoon; Li, Hongliang; Cao, Dejun

2015-03-01

The aim of this study is to discuss the application of rapid-prototyping model and surgical guide in the treatment of mandibular asymmetry malformation with normal occlusal relationship. Twenty-four mandibular asymmetry malformation patients with relatively normal occlusal relationship were included in this study. Surgical 3-dimensional rapid-prototyping mandibular models were made for all patients from the computed tomography (CT) DICOM data. The presurgical plan was designed on the model, and the surgical guiders for the osteotomy lines were manufactured. Genioplasty and/or mandibular osteotomy based on the presurgical plan were performed on these patients with the combined use of the rapid-prototyping model and surgical guides. All patients underwent postoperative CT scan and had at least 3-month follow-up. All patients were satisfied with the final results. According to the postoperative CT images and 3-month follow-up, all patients' mandibular asymmetry malformation was significantly improved, and the operation time was distinctly shortened relative to the conventional method. Rapid-prototyping model and surgical guide are viable auxiliary devices for the treatment of mandibular asymmetry malformation with relatively normal occlusal relationship. Combined use of them can make precise preoperative design, improve effects of operation, and shorten operating time.

Prevalence of radix entomolaris in mandibular permanent first molars: a study in a South Indian population.

PubMed

Chandra, Saurabh S; Chandra, Supriya; Shankar, Padmanabhan; Indira, Rajamani

2011-09-01

Anatomical racial variations are an acknowledged characteristic in permanent molars. Generally, mandibular first molars have 2 roots; however, the presence of a third root, radix entomolaris (RE), is a major anatomic variant among many population groups. This study evaluated the prevalence of permanent mandibular first molars featuring a distolingual root in a South Indian population. Five hundred patients of South Indian origin possessing bilateral mandibular first molars were selected. The radiographs of these patients were evaluated under optimal conditions. A total of 1000 mandibular first molars were screened and the incidence of 3-rooted mandibular first molars and the correlation between left and right side occurrence and between either gender was recorded. The prevalence of 3-rooted mandibular first molars was 18.6% of the patients examined and 13.3% of the teeth examined. There was no statistically significant difference between genders or side of occurrence (P > .05). The bilateral incidence of a symmetric distribution was 43.01%. RE is considered an Asiatic trait. The occurrence of this macrostructure in the South Indian population was 13.3%, which was lower than that of other patients of Mongoloid origin. The clinician must thoroughly examine the radiograph before initiation of endodontic therapy. Copyright © 2011 Mosby, Inc. All rights reserved.

Suppression of Autophagy in Osteocytes Mimics Skeletal Aging*

PubMed Central

Onal, Melda; Piemontese, Marilina; Xiong, Jinhu; Wang, Yiying; Han, Li; Ye, Shiqiao; Komatsu, Masaaki; Selig, Martin; Weinstein, Robert S.; Zhao, Haibo; Jilka, Robert L.; Almeida, Maria; Manolagas, Stavros C.; O'Brien, Charles A.

2013-01-01

Bone mass declines with age but the mechanisms responsible remain unclear. Here we demonstrate that deletion of a conditional allele for Atg7, a gene essential for autophagy, from osteocytes caused low bone mass in 6-month-old male and female mice. Cancellous bone volume and cortical thickness were decreased, and cortical porosity increased, in conditional knock-out mice compared with control littermates. These changes were associated with low osteoclast number, osteoblast number, bone formation rate, and wall width in the cancellous bone of conditional knock-out mice. In addition, oxidative stress was higher in the bones of conditional knock-out mice as measured by reactive oxygen species levels in the bone marrow and by p66shc phosphorylation in L6 vertebra. Each of these changes has been previously demonstrated in the bones of old versus young adult mice. Thus, these results demonstrate that suppression of autophagy in osteocytes mimics, in many aspects, the impact of aging on the skeleton and suggest that a decline in autophagy with age may contribute to the low bone mass associated with aging. PMID:23645674

Association between mandibular retrognathia and TMJ disorders in adult females.

PubMed

Miller, James R; Burgess, Jeffrey A; Critchlow, Cathy W

2004-01-01

This study assesses the association between temporomandibular joint (TMJ) disorders and mandibular retrognathia. We conducted a case-control study among women, aged 18-70 years, recruited from Kaiser Permanente Northwest Division (KPNW, Portland, OR) and Group Health Cooperative of Puget Sound (GHC, Seattle, WA). Cases (N= 160) were women seeking treatment for TMJ disorders at KPNW and GHC clinics. Controls (N=151) were women without TMJ disorders, selected from among adult female dental hygiene patients at KPNW or GHC enrollees. Case status was determined by questionnaire; mandibular sagittal position (orthognathic, mildly retrognathic, severely retrognathic, or prognathic) was measured using digitized facial photographs. Odds ratios (OR) and associated 95 percent confidence intervals (CI) estimated the magnitude of the association between TMJ disorders and mandibular sagittal position. Women with TMJ disorders were 4.0 times (95% CI=1.5, 10.8) more likely than controls to have severe retrognathia; no association with mild retrognathia or prognathia was seen. Results were similar when cases were restricted to those with recent onset of TMJ pain (OR=6.3; 95% CI=1.8, 21.8). We found a strong association between TMJ disorders and severe mandibular retrognathia in adult females. In some women this likely resulted from TMJ disorders influencing mandibular development over time. However, among a subset of women, our data support the reverse hypothesis--that severe mandibular retrognathia may influence the development of TMJ disorders. Despite this strong association, abnormal mandibular position contributed only a small portion to the overall rate at which women sought treatment for TMJ disorders.

Reduced mandibular range of motion in Duchenne Muscular Dystrophy: predictive factors.

PubMed

van Bruggen, H W; Van Den Engel-Hoek, L; Steenks, M H; Bronkhorst, E M; Creugers, N H J; de Groot, I J M; Kalaykova, S I

2015-06-01

Patients with Duchenne muscular dystrophy (DMD) experience negative effects upon feeding and oral health. We aimed to determine whether the mandibular range of motion in DMD is impaired and to explore predictive factors for the active maximum mouth opening (aMMO). 23 patients with DMD (mean age 16.7 ± 7.7 years) and 23 controls were assessed using a questionnaire about mandibular function and impairments. All participants underwent a clinical examination of the masticatory system, including measurement of mandibular range of motion and variables related to mandibular movements. In all patients, quantitative ultrasound of the digastric muscle and the geniohyoid muscle and the motor function measure (MFM) scale were performed. The patients were divided into early and late ambulatory stage (AS), early non-ambulatory stage (ENAS) and late non-ambulatory stage (LNAS). All mandibular movements were reduced in the patient group (P < 0.001) compared to the controls. Reduction in the aMMO (<40 mm) was found in 26% of the total patient group. LNAS patients had significantly smaller mandibular movements compared to AS and ENAS (P < 0.05). Multiple linear regression analysis for aMMO revealed a positive correlation with the body height and disease progression, with MFM total score as the strongest independent risk factor (R(2) = 0.71). Mandibular movements in DMD are significantly reduced and become more hampered with loss of motor function, including the sitting position, arm function, and neck and head control. We suggest that measurement of the aMMO becomes a part of routine care of patients with DMD. © 2015 John Wiley & Sons Ltd.

Incidence of three-rooted mandibular first molars among contemporary Japanese individuals determined using multidetector computed tomography.

PubMed

Ishii, Namiko; Sakuma, Ayaka; Makino, Yohsuke; Torimitsu, Suguru; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Hoshioka, Yumi; Iwase, Hirotaro; Saitoh, Hisako

2016-09-01

The purpose of this study was to determine the incidence of three-rooted mandibular first molars in a contemporary Japanese population using multidetector computed tomography (MDCT) and examine whether this characteristic root form may be useful for identification purposes. Prior to their forensic autopsies, we obtained MDCT scans of 365 cadavers (255 males, 110 females) with mandibular first molars on both sides. Altogether, 730 mandibular first molars were examined morphologically on reconstructed CT images, and the incidence of three-rooted molars was recorded. The results were analyzed statistically to determine sex and left-right differences using the chi-square test. In all, 189 (25.9%) of the 730 mandibular first molars had three roots: 79 (31.0%) in the 255 males and 35 (31.8%) in the 110 females. No statistically significant difference was found between the sexes. In the 39 individuals who had unilateral three-rooted mandibular first molars, 7 (17.9%) were on the left side and 32 (82.1%) were on the right side, indicating a statistically significant predominance on the right side. The incidence of three-rooted mandibular first molars in contemporary Japanese individuals was 25.9%, with no statistically significant sex difference, but in the case of unilateral three-rooted teeth, with a statistically significant predominance on the right side. Our study found that Japanese and northeastern Asians have a high incidence of the three-rooted mandibular first molars among individuals of Mongolian origin; this finding may be a useful screening tool for identification of unknown individuals. Copyright © 2016. Published by Elsevier Ireland Ltd.

Assessment of Growth Using Mandibular Canine Calcification Stages and Its Correlation with Modified MP3 Stages

PubMed Central

Nayak, US Krishna; Hegde, Gautam

2010-01-01

Background and objectives Orthodontic diagnosis and treatment planning for growing children must involve growth prediction, especially in the treatment of skeletal problems. Studies have shown that a strong association exists between skeletal maturity and dental calcification stages. The present study was therefore taken up to provide a simple and practical method for assessing skeletal maturity using a dental periapical film and standard dental X-ray machine, to compare the developmental stages of the mandibular canine with that of developmental stages of modified MP3 and to find out if any correlation exists, to determine if the developmental stages of the mandibular canine alone can be used as a reliable indicator for assessment of skeletal maturity. Methods A total of 160 periapical radiographs (80 males and 80 females), of the mandibular right canine and the MP3 region was taken and assessed according to the Dermirjian’s stages of dental calcification and the modified MP3 stages. Results The correlation between the developmental stages of MP3 and the mandibular right canine in male and female groups, is of high statistical significance (p = 0.001). The correlation coefficient between MP3 stages and developmental stages of mandibular canine and chronological age in male and females was found to be not significant. Conclusions The correlation between the mandibular canine calcification stages and MP3 stages was found to be significant. The developmental stages of the mandibular canine could be used very reliably as a sole indicator for assessment of skeletal maturity. PMID:27625553

Gender determination: Role of lip prints, finger prints and mandibular canine index

PubMed Central

KRISHNAN, RESHMA POOTHAKULATH; THANGAVELU, RADHIKA; RATHNAVELU, VIDHYA; NARASIMHAN, MALATHI

2016-01-01

Personal identification has a pivotal role in forensic investigations. Gender determination is an essential step in personal identification. Despite the advent of advanced techniques such as DNA fingerprinting, methods such as lip print and fingerprint analysis and mandibular canine index calculations are routinely used in gender determination, as they are simple and cost-effective. The present study investigated the hypothesis that lip print analysis is an effective tool in gender determination compared with fingerprint analysis and the mandibular canine index. The predominant patterns of lip prints and fingerprints were analyzed in males and females, and the efficacy of the mandibular canine index in gender determination was evaluated. The study group comprised 50 students, 25 males and 25 females who were 18–25 years of age. Lip prints and fingerprints were obtained and classified according to Tsuchihashi's classification and Kücken and Newell's classification, respectively. Mandibular impressions were made and the mandibular canine index was calculated. Type I and Type I' lip prints were predominant in females, and Type IV lip prints were predominant in males. The analysis of fingerprints revealed that the loop fingerprint pattern was predominant in both males and females. The mandibular canine index was not found to be significant in gender identification. The predominant patterns of lip prints were distinct for males and females; conversely, fingerprints were demonstrated to be similar in both genders. Therefore, lip prints hold an increased potential for gender determination, as compared with fingerprints, and the mandibular canine index is not a reliable indicator of gender. PMID:27284316

Endodontic treatment of mandibular canine with two roots and two canals.

PubMed

Moogi, Prashant P; Hegde, Reshma S; Prashanth, B R; Kumar, G Vinay; Biradar, Nandini

2012-11-01

In majority of cases, mandibular canines have one root and one root canal, although 15% may have two canals. Literature report shows incidence of two-rooted canine as low as 1.7%. This article reports a clinical case of endodontic treatment of mandibular canine with two roots and two canals.

Electron microscopic study of the mandibular glands of Kalotermes flavicollis fabr. (isoptera; calotermitidae).

PubMed

Cassier, P; Fain-Maurel, M A; Lebrun, D

1977-08-26

The mandibular glands of Kalotermes were examined in different castes. They show sexual dimorphism in the soldiers and primary reproductives, Moreover, in female soldiers and queens, mandibular gland cells contained numerous crystalline structures of mitochondrial origin. The role of these glands (secretion of saliva or pheromone) is discussed.

Endodontic treatment of an unusual connation of permanent mandibular molars: a case report.

PubMed

Liu, Shengbo; Fan, Bing; Peng, Bin; Fan, Mingwen; Bian, Zhuan

2006-10-01

A 27-year-old patient with an anomalous mandibular molar was referred for endodontic therapy. Clinical and radiographic examination revealed the connation of a second mandibular molar with a third molar. Challenging endodontic therapy was performed in the unusual connated molars. A 2-year recall showed good treatment result.

Consensus or controversy? The classification and treatment decision-making by 491 maxillofacial surgeons from around the world in three cases of a unilateral mandibular condyle fracture.

PubMed

Kommers, Sofie C; Boffano, Paolo; Forouzanfar, Tymour

2015-12-01

Many studies are available in the literature on both classification and treatment of unilateral mandibular condyle fractures. To date however, controversy regarding the best treatment for unilateral mandibular condyle fractures remains. In this study, an attempt was made to quantify the level of agreement between a sample of maxillofacial surgeons worldwide, on the classification and treatment decisions in three different unilateral mandibular condyle fracture cases. In total, 491 of 3044 participants responded. In all three mandibular condyle fracture cases, a fairly high level of disagreement was found. Only in the case of a subcondylar fracture, assuming dysocclusion was present, more than 81% of surgeons agreed that the best treatment would be open reduction and internal fixation. Based on the study results, there is considerable variation among surgeons worldwide with regard to treatment of unilateral mandibular condyle fracture. 3D imaging in higher fractures tends to lead to more invasive treatment decisions. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Evaluation of skeletal and dental age using third molar calcification, condylar height and length of the mandibular body.

PubMed

Kedarisetty, Sunil Gupta; Rao, Guttikonda Venkateswara; Rayapudi, Naveen; Korlepara, Rajani

2015-01-01

To identify the most reliable method for age estimation among three variables, that is, condylar height, length of mandibular body and third molar calcification by Demirjian's method. Orthopantomograms and lateral cephalograms of 60 patients with equal gender ratio were included in the study, among each gender 15 subjects were below 18 years and 15 subjects were above 18 years. Lateral cephalograms were traced, height of condyle and mandibular body are measured manually on the tracing paper, OPG's were observed on radiographic illuminator and maturity score of third molar calcification was noted according to Demirjian's method. All the measurements were subjected to statistical analysis. The results obtained are of no significant difference between estimated age and actual age with all three parameters (P > 0.9780 condylar height, P > 0.9515 length of mandibular body, P > 0.8611 third molar calcification). Among these three, length of mandibular body shows least standard error test (i.e. 0.188). Although all three parameters can be used for age estimation, length of mandibular body is more reliable followed by height of condyle and third molar calcification.

Influence of occlusal plane inclination and mandibular deviation on esthetics

PubMed Central

Corte, Cristiane Cherobini Dalla; da Silveira, Bruno Lopes; Marquezan, Mariana

2015-01-01

Objective: The aim of this study was to assess the degree of perception of occlusal plane inclination and mandibular deviation in facial esthetics, assessed by laypeople, dentists and orthodontists. Methods: A woman with 5.88° of inclination and 5.54 mm of mandibular deviation was selected and, based on her original photograph, four new images were created correcting the deviations and creating more symmetric faces and smiles. Examiners assessed the images by means of a questionnaire. Their opinions were compared by qualitative and quantitative analyses. Results: A total of 45 laypeople, 27 dentists and 31 orthodontists filled out the questionnaires. All groups were able to perceive the asymmetry; however, orthodontists were more sensitive, identifying asymmetries as from 4.32° of occlusal plane inclination and 4.155 mm of mandibular deviation (p< 0.05). The other categories of evaluators identified asymmetries and assigned significantly lower grades, starting from 5.88° of occlusal plane inclination and 5.54 mm of mandibular deviation (p< 0.05). Conclusion: Occlusal plane inclination and mandibular deviation were perceived by all groups, but orthodontists presented higher perception of deviations. PMID:26560821

[Cervical vertebrae: Mandibular growth dynamism indicators?].

PubMed

Raberin, Monique; Cozor, Ilinca; Gobert-Jacquart, Stéphanie

2012-03-01

A study of mandibular growth maturation was performed on a population of 103 patients during orthodontic treatment (69 girls and 34 boys) from 11 to 16 years, having initially a Class II skeletal discrepancy. The relationship between wrist maturation indices and the cervical vertebrae maturation was studied by Lamparski classification. Significant correlations were found between Björk stages, MP3=, MP3 cap and MP3 U and respectively Lamparski stages as CVS 2, CVS 3-4 and CVS 5-6. This retrospective longitudinal study identified three mandibular variables at three different maturation stages according to Björk classification and to the six stages of Lamparski classification. The relationships between these different maturation stages and a quantitative mandibular response permit to estimate optimal time for our orthodontic therapy. The results indicate a significant increase in mandibular length between CVS 4 and CVS 5, suggesting the persistence of a condylar response to a stimulation therapy after CVS3 or CVS 4 stages (MP3 cap). Mandibular growth seems to continue after MP3 U stage or CVS 5 stage. © EDP Sciences, SFODF, 2012.

[Distal movement of the mandibular dentition in the treatment of patients with Class III skeletal pattern].

PubMed

Mou, Lan; Xu, Gengchi; Han, Yaohui; Ge, Zhenlin

2015-06-01

To evaluate the outcome of patients with skeletal Class III malocclusion treated with extraction of mandibular third molars and distalization of molars using implant anchorage combined with MBT appliance. Fifteen patients (mean age 24.0 ± 5.8) with skeletal Class III malocclusion were selected. The mandibular third molars were extracted and the mandibular molars were moved distally using implant combined with MBT appliance. Cephalometric analysis was carried out before and after treatment. After active treatment, ANB, Wits distance, AB-NP and the distance between upper and lower lip position to SnPg' increased by 1.65° ± 1.04°, (4.39 ± 1.93) mm, 3.20° ± 1.61° and (1.13 ± 0.99) mm, respectively. The differences were statistically significant (P < 0.05). The skeletal Class III patients in the permanent dentition could be treated successfully with extraction of mandibular third molars and distalization of mandibular molars using implant anchorage combined with MBT appliance. The soft-tissue profile was improved.

Endodontic treatment of mandibular molars with atypical root canal anatomy: reports of 4 cases.

PubMed

Chauhan, Raju; Singh, Shweta

2015-01-01

The variations in root canal anatomy of multirooted teeth represent a continuous challenge to endodontic diagnosis and treatment. Although the most common configuration of mandibular molars is one containing 2 roots and 3 root canals, there are many different combinations. Very rarely, an additional third (supernumerary) root is seen. When it is located distolingually to the main distal root, this third root is called radix entomolaris (RE), and when it is located mesiobuccally to the mesial root, it is called radix paramolaris (RP). Variations of root canal systems need not always be in the form of extra roots or extra canals. Single roots with single canals can also occur. A general dentist should be aware of these unusual root canal morphologies in mandibular molars for the success of endodontic treatment. These case reports describe the root canal treatment of a case of RE in the mandibular first molar, 2 rare cases of RP (1 each in the mandibular first and second molars), and a mandibular second molar with a single root and root canal.

Morphologic and functional implications of the surgical-orthodontic management of mandibular prognathism: a comprehensive review.

PubMed

Athanasiou, A E

1993-05-01

The aim of this review is to present the various morphologic and functional implications of the surgical-orthodontic management of mandibular prognathism, thus providing a more complete determination of the efficacy of this modality of treatment. Major conclusions that can be drawn from the bibliography indicate that: (1) After treatment considerable improvement takes place on the soft tissue and dentoskeletal profile, occlusal tooth contacts, and temporomandibular joint function and and pain; (2) Surgical management of mandibular prognathism can be associated with decreased maximum interincisal opening; (3) Although immediately after surgery there is a tendency for the condyles to be distracted downward and anteriorly from their preoperative position, in long-term postsurgery the condyles, on the average, regain their initial position; (4) Compensatory alterations in the pharyngeal, suprahyoid, and infrahyoid muscular regions take place postoperatively; (5) Skeletal changes after mandibular setback to correct mandibular prognathism occur frequently, but their magnitude and patterns exhibit variation and are not necessarily detrimental; and (6) Fulfillment of expectations toward surgical-orthodontic management of mandibular prognathism was reported to be frequent.

Pathological mandibular fracture: A severe complication of periimplantitis

PubMed Central

Rodriguez-Campo, Francisco; Naval-Parra, Beatriz; Sastre-Pérez, Jesús

2015-01-01

Nowadays, dental implant treatment is a very common option for patients even in medical compromised conditons. Some complications related to them have been described. Periimplantitis (PI) is one of the biggest concerns complications of these kind of treatments, probably has a multifactorial aethiology. Usually the consequences of PI are the loss of the implants and prostheses, expenses of money and time for dentists and patients. Very often PI implies the necesity of repeating the treatment . Pathological mandibular fracture due to PI is a severe but infrequent complication after dental implant treatment, especially after PI. In this study we present three cases of mandibular pathologic fractures among patients with different medical and dental records but similar management: two of them had been treated years ago of oral squamous cell carcinoma with surgery and radiotherapy, the other patient received oral bisphosphonates for osteoporosis some years after implantation. We analized the causes, consequences and posible prevention of these fractures as well as the special features of this kind of mandibular fractures and the different existing treatments. Key words:Periimplantitis, pathological mandibular fracture, mandibular atrophy, bicortical implants. PMID:26155355

Pathological mandibular fracture: A severe complication of periimplantitis.

PubMed

Naval-Gías, Luis; Rodriguez-Campo, Francisco; Naval-Parra, Beatriz; Sastre-Pérez, Jesús

2015-04-01

Nowadays, dental implant treatment is a very common option for patients even in medical compromised conditons. Some complications related to them have been described. Periimplantitis (PI) is one of the biggest concerns complications of these kind of treatments, probably has a multifactorial aethiology. Usually the consequences of PI are the loss of the implants and prostheses, expenses of money and time for dentists and patients. Very often PI implies the necesity of repeating the treatment . Pathological mandibular fracture due to PI is a severe but infrequent complication after dental implant treatment, especially after PI. In this study we present three cases of mandibular pathologic fractures among patients with different medical and dental records but similar management: two of them had been treated years ago of oral squamous cell carcinoma with surgery and radiotherapy, the other patient received oral bisphosphonates for osteoporosis some years after implantation. We analized the causes, consequences and posible prevention of these fractures as well as the special features of this kind of mandibular fractures and the different existing treatments. Key words:Periimplantitis, pathological mandibular fracture, mandibular atrophy, bicortical implants.

Periodontal regeneration with nano-hyroxyapatite-coated silk scaffolds in dogs

PubMed Central

Yang, Cheryl; Lee, Jung-Seok; Jung, Ui-Won; Seo, Young-Kwon; Park, Jung-Keug

2013-01-01

Purpose In this study, we investigated the effect of silk scaffolds on one-wall periodontal intrabony defects. We conjugated nano-hydroxyapatite (nHA) onto a silk scaffold and then seeded periodontal ligament cells (PDLCs) or dental pulp cells (DPCs) onto the scaffold. Methods Five dogs were used in this study. Bilateral 4 mm×2 mm (depth×mesiodistal width), one-wall intrabony periodontal defects were surgically created on the distal side of the mandibular second premolar and the mesial side of the mandibular fourth premolar. In each dog, four of the defects were separately and randomly assigned to the following groups: the PDLC-cultured scaffold transplantation group (PDLC group), the DPC-cultured scaffold transplantation group (DPC group), the normal saline-soaked scaffold transplantation group, and the control group. The animals were euthanized following an 8-week healing interval for clinical, scanning electron microscopy (SEM), and histologic evaluations. Results There was no sign of inflammation or other clinical signs of postoperative complications. The examination of cell-seeded constructs by SEM provided visual confirmation of the favorable characteristics of nHA-coated silk scaffolds for tissue engineering. The scaffolds exhibited a firm connective porous structure in cross section, and after PDLCs and DPCs were seeded onto the scaffolds and cultured for 3 weeks, the attachment of well-spread cells and the formation of extracellular matrix (ECM) were observed. The histologic analysis revealed that a well-maintained grafted volume was present at all experimental sites for 8 weeks. Small amounts of inflammatory cells were seen within the scaffolds. The PDLC and DPC groups did not have remarkably different histologic appearances. Conclusions These observations indicate that nHA-coated silk scaffolds can be considered to be potentially useful biomaterials for periodontal regeneration. PMID:24455445

Effect of defective collagen synthesis on epithelial implant interface: lathyritic model in dogs. An experimental preliminary study.

PubMed

Cengiz, Murat Inanç; Kirtiloğlu, Tuğrul; Acikgoz, Gökhan; Trisi, Paolo; Wang, Hom-Lay

2012-04-01

Peri-implant mucosa is composed of 2 compartments: a marginal junctional epithelium and a zone of connective tissue attachment. Both structures consist mainly of collagen. Lathyrism is characterized by defective collagen synthesis due to inhibition of lysyl oxidase, an enzyme that is essential for interfibrillar collagen cross-linking. The lathyritic agent beta-aminoproprionitrile (β-APN) is considered a suitable agent to disrupt the connective tissue metabolism. Therefore, the purpose of this study was to assess the effect of defective connective tissue metabolism on epithelial implant interface by using β-APN created chronic lathyrism in the canine model. Two 1-year-old male dogs were included in this study. A β-APN dosage of 5 mg/0.4 mL/volume 100 g/body weight was given to the test dog for 10 months, until lathyritic symptoms developed. After this, the mandibular premolar teeth (p2, p3, p4) of both dogs were atraumatically extracted, and the investigators waited 3 months before implants were placed. In the test dog, 3 implants were placed in the left mandible, and 2 implants were placed in the right mandible. In the control dog, 2 implants were placed in the left mandibular premolar site. The dogs were sacrificed 10 months after healing. Peri-implant tissues obtained from the dogs were examined histomorphologically and histopathologically. Bone to implant contact (BIC) values and bone volumes (BV) were lower in the lathyritic group compared to the control group; however, no statistical significance was found. Significant histologic and histomorphometric changes were observed in peri-implant bone, connective tissue, and peri-implant mucosal width between test and control implants. Defective collagen metabolism such as lathyrism may negatively influence the interface between implant and surrounding soft tissue attachment.

Autotransplantation of mandibular third molar: a case report.

PubMed

Ravi Kumar, Pabbati; Jyothi, Mandava; Sirisha, Kantheti; Racca, Khushboo; Uma, Chalasani

2012-01-01

Autogenous transplantation is a feasible, fast, and economical option for the treatment of nonsalvageable teeth when a suitable donor tooth is available. This paper presents successful autotransplantation of a mature mandibular left third molar (38) without anatomical variances is used to replace a mandibular left second molar (37). The mandibular second molar was nonrestorable due to extensive root caries and resorption of distal root. After extraction of mandibular second and third molars, root canal therapy was done for the third molar extraorally, and the tooth was reimplanted into the extracted socket of second molar site. After one year, clinical and radiographic examination revealed satisfactory outcome with no signs or symptoms suggestive of pathology. In selected cases, autogenous tooth transplantation, even after complete root formation of the donor tooth, may be considered as a practical treatment alternative to conventional prosthetic rehabilitation or implant treatment.

Are Biodegradable Plates Applicable in Endoscope-Assisted Open Reduction and Internal Fixation of Mandibular Subcondyle Fractures?

PubMed

Son, Jang-Ho; Ha, Jinhee; Cho, Yeong-Cheol; Sung, Iel-Yong

2017-08-01

To investigate whether biodegradable plates are applicable in endoscope-assisted open reduction and internal fixation (EAORIF) of mandibular subcondyle fractures. This retrospective case-series study included patients with mandibular subcondyle fractures treated with EAORIF using an unsintered hydroxyapatite particles/poly-l-lactide biodegradable plate system, with at least 6 months of clinical follow-up data available. The outcome variables were fracture healing with postoperative stability and postoperative complications. Other variables included age, gender, fracture site, cause of injury, accompanying mandibular fracture, total follow-up period, fracture classification, extent of displacement, preoperative status of occlusion, preoperative mandibular movements, fixation materials in accompanying mandibular fracture, location and number of fixation plates, periods of intermaxillary fixation/elastic bands, and postoperative mandibular movements. Fracture healing in these patients was assessed by comparing the immediate postoperative cone-beam computed tomography (CBCT) images with those obtained at least 3 months after surgery. A total of 11 patients, 9 male and 2 female, with a mean ± standard deviation age of 35.3 ± 15.9 years, were included. The mean follow-up period was 18.8 ± 7.8 months. Four patients had an accompanying mandibular fracture. Two 4-hole, 2.0-mm biodegradable plates were fixed with 6-mm screws along the posterior border of the mandibular ramus and near the sigmoid notch. Complete bone formation around the fracture lines or fading of the fracture lines, with no change in the position of the fractured segments, was observed on the postoperative CBCT images at 3 months. With the exception of 2 patients, no patient complained of plate palpability, deviation in occlusion, or discomfort during the postoperative follow-up period. EAORIF using biodegradable plates for mandible subcondylar fractures is a stable and reliable method, with considerable advantages compared with titanium plates. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Occlusal plane rotation: aesthetic enhancement in mandibular micrognathia.

PubMed

Rosen, H M

1993-06-01

Patients afflicted with extreme degrees of mandibular micrognathia typically have vertically deficient rami as well as sagittally deficient mandibular bodies. This results in deficient posterior facial height, an obtuse gonial angle, excessively steep occlusal and mandibular planes, and a compensatory increase in anterior facial height. The entire maxillomandibular complex is overrotated in a clockwise direction. Standard orthognathic surgical correction fails to address this rotational deformity. As a consequence, the achieved projection of the lower face is inadequate, posterior facial height is further reduced, and occlusal and mandibular planes remain steep. Eleven patients with severe mandibular micrognathia underwent a surgical correction involving occlusal plane rotation to its normal orientation relative to Frankfort horizontal. This was accomplished by Le Fort I osteotomy to shorten the anterior maxilla (creating open bites in seven patients and making preexisting open bites worse in four patients) and sagittal split ramus osteotomies to advance and rotate the mandibular body counterclockwise, thus closing the surgically produced open bite. Counterclockwise rotation of the mandible afforded significantly greater sagittal displacement at the B point (mean 17 mm) than at the first molar (mean 10 mm) and produced adequate degrees of projection of the lower face when accompanied by a modest sliding genioplasty (mean 6.9 mm). Total advancement at the pogonion was a mean of 25.2 mm. In addition, posterior facial height was preserved, and mandibular and occlusal planes were normalized to mean angles of 27 and 10 degrees, respectively. At follow-up, which ranged from 9 to 24 months with a mean of 14.1 months, the mean sagittal relapse at the B point was 1.9 mm. Although heretofore considered unstable and therefore not clinically accepted, maxillomandibular counterclockwise rotation to normalize the occlusal plane rotational deformity provides stable, aesthetically superior results in patients with extreme degrees of mandibular micrognathia. Extended follow-up will be necessary to document long-term stability.

Two-Implant-Supported Mandibular Overdentures: Do Clinical Denture Quality and Inter-Implant Distance Affect Patient Satisfaction?

PubMed

Alfadda, Sara A; Al Amri, Mohammad D; Al-Ohali, Amal; Al-Hakami, Arwa; Al-Madhi, Noura

To investigate the following three null hypotheses in patients rehabilitated with a mandibular overdenture supported by two unsplinted implants: (1) patient satisfaction is not related to the clinical quality of the dentures; (2) inter-implant distance (IID) has no effect on the clinical quality of the dentures; and (3) IID does not influence patient satisfaction. Forty edentulous patients who were rehabilitated with a two-implant-supported mandibular overdenture participated in the study. Independent investigators evaluated the dentures on the basis of five clinical criteria using the validated Denture Quality Evaluation Form, and the patients completed the validated Denture Satisfaction Scale. Irreversible hydrocolloid impressions of the mandible were made and poured immediately in die stone. The IID was measured by adapting an orthodontic wire to the mandibular alveolar ridge crest, extending from the center of one implant to the center of the other. Spearman correlation analyses were used to identify possible correlations, with a significance level set at P < .05. The clinicians' overall mean rating of the clinical quality of the dentures was 91.5% (standard deviation 6.27%). The stability of the mandibular overdenture and of the maxillary conventional complete denture was significantly related to satisfaction (r = 0.389 and r = 0.44, respectively). Significant associations were found between the mandibular stability items and satisfaction with both maxillary and mandibular dentures. The stability of the maxillary denture was significantly associated with patient satisfaction with mandibular denture retention, stability, and comfort. None of the 12 denture satisfaction items were significantly associated with IID. Similarly, IID did not have an effect on the quality of either denture in terms of retention, stability, or occlusion. Denture stability was the feature that had the most influence on patient satisfaction with the mandibular overdenture and with the maxillary conventional denture. IID had no effect on the clinical quality of either denture and did not influence patient satisfaction.

Restricted Mandibular Movement Attributed to Ossification of Mandibular Depressors and Medial Pterygoid Muscles in Patients With Fibrodysplasia Ossificans Progressiva: A Report of 3 Cases.

PubMed

Okuno, Tetsuko; Suzuki, Hitoshi; Inoue, Akio; Kusukawa, Jingo

2017-09-01

Fibrodysplasia ossificans progressiva (FOP) is an extremely rare genetic condition characterized by congenital malformation and progressive heterotopic ossification (HO) caused by a recurrent single nucleotide substitution at position 617 in the ACVR1 gene. As the condition progresses, HO leads to joint ankylosis, breathing difficulties, and mouth-opening restriction, and it can shorten the patient's lifespan. This report describes 3 cases of FOP confirmed by genetic testing in patients with restricted mouth opening. Each patient presented a different onset and degree of jaw movement restriction. The anatomic ossification site of the mandibular joint was examined in each patient using reconstructed computed tomographic (CT) images and 3-dimensional reconstructed CT (3D-CT) images. A 29-year-old woman complained of jaw movement restriction since 13 years of age. 3D-CT image of the mandibular joint showed an osseous bridge, formed by the mandibular depressors that open the mouth, between the hyoid bone and the mentum of the mandible. A 39-year-old man presented with jaw movement restriction that developed at 3 years of age after a mouth injury. 3D-CT image of the jaw showed ankylosis of the jaw from ossification of the mandibular depressors that was worse than in patient 1. CT images showed no HO findings of the masticatory muscles. To the authors' knowledge, these are the first 2 case descriptions of the anatomic site of ankylosis involving HO of the mandibular depressors in the jaw resulting from FOP. In contrast, a 62-year-old bedridden woman with an interincisal distance longer than 10 mm (onset, 39 years of age) had no HO of the mandibular depressors and slight HO of the medial pterygoid muscle on the right and left sides. These findings suggest that restricted mouth opening varies according to the presence or absence of HO of the mandibular depressors. Copyright © 2017. Published by Elsevier Inc.

A Feedback-Controlled Mandibular Positioner Identifies Individuals With Sleep Apnea Who Will Respond to Oral Appliance Therapy.

PubMed

Remmers, John E; Topor, Zbigniew; Grosse, Joshua; Vranjes, Nikola; Mosca, Erin V; Brant, Rollin; Bruehlmann, Sabina; Charkhandeh, Shouresh; Zareian Jahromi, Seyed Abdolali

2017-07-15

Mandibular protruding oral appliances represent a potentially important therapy for obstructive sleep apnea (OSA). However, their clinical utility is limited by a less-than-ideal efficacy rate and uncertainty regarding an efficacious mandibular position, pointing to the need for a tool to assist in delivery of the therapy. The current study assesses the ability to prospectively identify therapeutic responders and determine an efficacious mandibular position. Individuals (n = 202) with OSA participated in a blinded, 2-part investigation. A system for identifying therapeutic responders was developed in part 1 (n = 149); the predictive accuracy of this system was prospectively evaluated on a new population in part 2 (n = 53). Each participant underwent a 2-night, in-home feedback-controlled mandibular positioner (FCMP) test, followed by treatment with a custom oral appliance and an outcome study with the oral appliance in place. A machine learning classification system was trained to predict therapeutic outcome on data obtained from FCMP studies on part 1 participants. The accuracy of this trained system was then evaluated on part 2 participants by examining the agreement between prospectively predicted outcome and observed outcome. A predicted efficacious mandibular position was derived from each FCMP study. Predictive accuracy was as follows: sensitivity 85%; specificity 93%; positive predictive value 97%; and negative predictive value 72%. Of participants correctly predicted to respond to therapy, the predicted mandibular protrusive position proved efficacious in 86% of cases. An unattended, in-home FCMP test prospectively identifies individuals with OSA who will respond to oral appliance therapy and provides an efficacious mandibular position. The trial that this study reports on is registered on www.clinicaltrials.gov, ID NCT03011762, study name: Feasibility and Predictive Accuracy of an In-Home Computer Controlled Mandibular Positioner in Identifying Favourable Candidates for Oral Appliance Therapy. © 2017 American Academy of Sleep Medicine

Sliding mechanics with microscrew implant anchorage.

PubMed

Park, Hyo-Sang; Kwon, Tae-Geon

2004-10-01

Three cases are illustrated. One was treated with maxillary microscrew implants, another with mandibular microscrew implants, and the third with both maxillary and mandibular microscrew implants. With the maxillary microscrew implants, the maxillary anterior teeth were retracted bodily with a slight intrusion and all the premolar extraction space was closed without loss of anchorage. Furthermore, the maxillary posterior teeth showed distal movement. The mandibular microscrew implants controlled the vertical position of the mandibular posterior teeth and played an important role in improving the facial profile. The efficacy of sliding mechanics with microscrew implant anchorage on the treatment of skeletal Class II malocclusion is also discussed.

A novel technique for preventing skin pressure sores using a rubber tube during surgical treatment of mandibular condyle fractures.

PubMed

Kawase-Koga, Yoko; Mori, Yoshiyuki; Hoshi, Kazuhito; Takato, Tsuyoshi

2013-11-01

Craniofacial surgery occasionally results in sores and necrosis of the facial skin because of pressure from surgical instruments. During surgical treatment of mandibular condylar process fractures, the main mandibular fragment is routinely retracted downward using a wire to achieve a satisfactory anatomic reduction. This procedure may injure the facial skin. This potential complication is easily overlooked by medical staff, but it is easily preventable. We herein describe a method of using a rubber tube to avoid causing pressure sores of the facial skin during surgical treatment of mandibular condylar process fractures.

Effects of posttreatment skeletal maturity measured with the cervical vertebral maturation method on incisor alignment relapse.

PubMed

Fudalej, Piotr; Rothe, Laura E; Bollen, Anne-Marie

2008-08-01

Our aim was to test the hypothesis that relapse of incisor alignment is associated with skeletal maturity at the end of treatment, as assessed with the cervical vertebral maturation (CVM) method. This was a case-control study with information from the postretention database at the University of Washington. Mandibular incisor irregularity (II) at least 10 years out of retention (T3) was used to define the subjects (II >6 mm, relapse group) and the controls (II <3.5 mm, stable group). The following model measurements were made: II at pretreatment (T1), II at posttreatment (T2), and intercanine width at T1 and T2. On cephalograms taken T2, the CVM status was determined. Logistic regression analyses were used to determine the association between relapse and CVM status after treatment. The models were adjusted for potentially confounding variables (II at pretreatment and posttreatment, intercanine width change during treatment, sex, age at T2, and treatment alternatives). No association between CVM stage at T2 and relapse was found (P = 0.89). Both groups had similar distributions of the CVM stages (P >0.05). Pretreatment II and postretention time were found to be correlated with long-term incisor stability (P = 0.007 and 0.034, respectively). Sex was not related to relapse (P = 0.33). Maturity of craniofacial structures at the end of treatment evaluated with the CVM method is not associated with long-term stability of incisor alignment.

Impaired positioning of the gape in whiplash-associated disorders.

PubMed

Zafar, Hamayun; Nordh, Erik; Eriksson, Per-Olof

2006-01-01

We have previously introduced a new concept for natural jaw function suggesting that "functional jaw movements" are the result of coordinated jaw and neck muscle activation, leading to simultaneous movements in the temporomandibular, atlanto-occipital and cervical spine joints. Thus, jaw function requires a healthy state of both the jaw and the neck motor systems. The aim of this study was to examine the positioning of the gape in space during maximal jaw opening at fast and slow speed in healthy as well as whiplash-associated disorders (WAD) individuals. A wireless optoelectronic technique for three-dimensional movement recording was used. Subjects were seated in an upright position, with back support up to the mid-scapular level without headrest. The position of the gape in space was defined as the vertical midpoint position of the gape at maximal jaw opening (MP). In healthy, the MP generally coincided with the reference position at the start of jaw opening. In the WAD group, the MP was significantly lower than the reference position. No sex or speed related differences were found. The results suggest that both the width and orientation of the gape in space relies on coordinated jaw and neck muscle activation and mandibular and head-neck movements. This study also suggests an association between neck pain and dysfunction following trauma, and reduced width and impaired positioning of the gape in space. Finally, the MP seems to be a useful marker in evaluation of the functional state of the jaw-neck motor system.

Accuracy of laser-scanned models compared to plaster models and cone-beam computed tomography.

PubMed

Kim, Jooseong; Heo, Giseon; Lagravère, Manuel O

2014-05-01

To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models. Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data. The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations>0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm±0.38 mm. In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

Analysis of intra-arch and interarch measurements from digital models with 2 impression materials and a modeling process based on cone-beam computed tomography.

PubMed

White, Aaron J; Fallis, Drew W; Vandewalle, Kraig S

2010-04-01

Study models are an essential part of an orthodontic record. Digital models are now available. One option for generating a digital model is cone-beam computed tomography (CBCT) scanning of orthodontic impressions and bite registrations. However, the accuracy of digital measurements from models generated by this method has yet to be thoroughly evaluated. A plastic typodont was modified with reference points for standardized intra-arch and interarch measurements, and 16 sets of maxillary and mandibular vinylpolysiloxane and alginate impressions were made. A copper wax-bite registration was made with the typodont in maximum intercuspal position to accompany each set of impressions. The impressions were shipped to OrthoProofUSA (Albuquerque, NM), where digital orthodontic models were generated via CBCT. Intra-arch and interarch measurements were made directly on the typodont with electronic digital calipers and on the digital models by using OrthoProofUSA's proprietary DigiModel software. Percentage differences from the typodont of all intra-arch measurements in the alginate and vinylpolysiloxane groups were low, from 0.1% to 0.7%. Statistical analysis of the intra-arch percentage differences from the typodont of the alginate and vinylpolysiloxane groups had a statistically significant difference between the groups only for maxillary intermolar width. However, because of the small percentage differences, this was not considered clinically significant for orthodontic measurements. Percentage differences from the typodont of all interarch measurements in the alginate and vinylpolysiloxane groups were much higher, from 3.3% to 10.7%. Statistical analysis of the interarch percentage differences from the typodont of the alginate and vinylpolysiloxane groups showed statistically significant differences between the groups in both the maxillary right canine to mandibular right canine (alginate with a lower percentage difference than vinylpolysiloxane) and the maxillary left second molar to mandibular left second molar (alginate with a greater percentage difference than vinylpolysiloxane) segments. This difference, ranging from 0.24 to 0.72 mm, is clinically significant. In this study, digital orthodontic models from CBCT scans of alginate and vinylpolysiloxane impressions provided a dimensionally accurate representation of intra-arch relationships for orthodontic evaluation. However, the use of copper wax-bite registrations in this CBCT-based process did not result in an accurate digital representation of interarch relationships. Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Spline analysis of the mandible in human subjects with class III malocclusion.

PubMed

Singh, G D; McNamara, J A; Lozanoff, S

1997-05-01

This study determines deformations that contribute to a Class III mandibular morphology, employing thin-plate spline (TPS) analysis. A total of 133 lateral cephalographs of prepubertal children of European-American descent with either a Class I molar occlusion or a Class III malocclusion were compared. The cephalographs were traced and checked, and eight homologous landmarks on the mandible were identified and digitized. The datasets were scaled to an equivalent size and subjected to statistical analyses. These tests indicated significant differences between average Class I and Class III mandibular morphologies. When the sample was subdivided into seven age and sex-matched groups statistical differences were maintained for each group. TPS analysis indicated that both affine (uniform) and non-affine transformations contribute towards the total spline, and towards the average mandibular morphology at each age group. For non-affine transformations, partial warp 5 had the highest magnitude, indicating large-scale deformations of the mandibular configuration between articulare and pogonion. In contrast, partial warp 1 indicated localized shape changes in the mandibular symphyseal region. It is concluded that large spatial-scale deformations affect the body of the mandible, in combination with localized distortions further anteriorly. These deformations may represent a developmental elongation of the mandibular corpus antero-posteriorly that, allied with symphyseal changes, leads to the appearance of a Class III prognathic mandibular profile.

Preliminary optical coherence tomography investigation of the temporo-mandibular joint disc

NASA Astrophysics Data System (ADS)

Mărcăuteanu, Corina; Demjan, Enikö; Sinescu, Cosmin; Negrutiu, Meda; Motoc, Adrian; Lighezan, Rodica; Vasile, Liliana; Hughes, Mike; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

2010-02-01

Aim and objectives. The morphology and position of the temporo-mandibular disc are key issues in the diagnosis and treatment of arthrogenous temporo-mandibular disorders. Magnetic resonance imaging and arthroscopy are used today to identify: flattening of the pars posterior of the disc, perforation and/or adhesions in the pars intermedia of the disc and disc displacements. The present study proposes the investigation of the temporo-mandibular joint disc by optical coherence tomography (OCT). Material and methods. 8 human temporo-mandibular joint discs were harvested from dead subjects, under 40 year of age, and conserved in formalin. They had a normal morphology, with a thicker pars posterior (2,6 mm on the average) and a thinner pars intermedia (1mm on the average). We investigated the disc samples using two different OCT systems: an en-face OCT (time domain (TD)-OCT) system, working at 1300 nm (C-scan and B-scan mode) and a spectral OCT system (a Fourier domain (FD)-OCT) system , working at 840 nm (B-scan mode). Results. The OCT investigation of the temporo-mandibular joint discs revealed a homogeneous microstructure. The longer wavelength of the TD-OCT offers a higher penetration depth (2,5 mm in air), which is important for the analysis of the pars posterior, while the FD-OCT is much faster. Conclusions: OCT is a promising imaging method for the microstructural characterization of the temporo-mandibular disc.

The Ball Welding Bar: A New Solution for the Immediate Loading of Screw-Retained, Mandibular Fixed Full Arch Prostheses

PubMed Central

Bacchiocchi, Danilo

2017-01-01

Purpose To present a new intraoral welding technique, which can be used to manufacture screw-retained, mandibular fixed full-arch prostheses. Methods Over a 4-year period, all patients with complete mandibular edentulism or irreparably compromised mandibular dentition, who will restore the masticatory function with a fixed mandibular prosthesis, were considered for inclusion in this study. The “Ball Welding Bar” (BWB) technique is characterised by smooth prosthetic cylinders, interconnected by means of titanium bars which are adjustable in terms of distance from ball terminals and are inserted in the rotating rings of the cylinders. All the components are welded and self-posing. Results Forty-two patients (18 males; 24 females; mean age 64.2 ± 6.7 years) were enrolled and 210 fixtures were inserted to support 42 mandibular screw-retained, fixed full-arch prostheses. After two years of loading, 2 fixtures were lost, for an implant survival rate of 97.7%. Five implants suffered from peri-implant mucositis and 3 implants for peri-implantitis. Three of the prostheses (3/42) required repair for fracture (7.1%): the prosthetic success was 92.9%. Conclusions The BWB technique seems to represent a reliable technique for the fabrication of screw-retained mandibular fixed full-arch prostheses. This study was registered in the ISRCTN register with number ISRCTN71229338. PMID:28835752

Prevalence of Extra Roots in Permanent Mandibular First Molars in Iranian Population: A CBCT Analysis

PubMed Central

Rahimi, Saeed; Mokhtari, Hadi; Ranjkesh, Bahram; Johari, Masoomeh; Frough Reyhani, Mohammad; Shahi, Shahriar; Seif Reyhani, Sina

2017-01-01

Introduction: Having knowledge about the anatomy of root canal system is essential for success of endodontic treatment. The present study used cone-beam computed tomography (CBCT), to evaluate the prevalence of third root in mandibular first molars in a selected Iranian population. Methods and Materials: A total of 386 CBCT images from subjects referred to oral and maxillofacial radiology department of dental faculty of Tabriz University of Medical Sciences from 2011 to 2013 were selected and evaluated for this study and the cases with well-developed permanent mandibular first molars were included. The 3D images were reconstructed in axial cross sections and evaluated by two endodontists for the presence of the third extra lingual (radix entomolaris) or buccal (radix paramolaris) root. The chi-squared test was used to evaluate the relationship between gender and bilateral incidence of extra roots in mandibular first molars. Results: The distribution of three-rooted mandibular first molars with an additional root was 3%, (3.53% in female and 2.50% in male patients). There was no significant relationship between gender and bilateral occurrence of three-rooted mandibular first molars. Conclusion: The occurrence of three-rooted mandibular first molars in Iranian population is not uncommon which should be taken into consideration by the dental practitioners during root canal treatment of these teeth. PMID:28179928

Mandibular osteoradionecrosis in squamous cell carcinoma of the oral cavity and oropharynx: incidence and risk factors.

PubMed

Monnier, Yan; Broome, Martin; Betz, Michael; Bouferrache, Kahina; Ozsahin, Mahmut; Jaques, Bertrand

2011-05-01

Mandibular osteoradionecrosis (ORN) is a serious complication of radiotherapy (RT) in head and neck cancer patients. The aim of this study was to analyze the incidence of and risk factors for mandibular ORN in squamous cell carcinoma (SCC) of the oral cavity and oropharynx. Case series with chart review. University tertiary care center for head and neck oncology. Seventy-three patients treated for stage I to IV SCC of the oral cavity and oropharynx between 2000 and 2007, with a minimum follow-up of 2 years, were included in the study. Treatment modalities included both RT with curative intent and adjuvant RT following tumor surgery. The log-rank test and Cox model were used for univariate and multivariate analyses. The incidence of mandibular ORN was 40% at 5 years. Using univariate analysis, the following risk factors were identified: oral cavity tumors (P < .01), bone invasion (P < .02), any surgery prior to RT (P < .04), and bone surgery (P < .0001). By multivariate analysis, mandibular surgery proved to be the most important risk factor and the only one reaching statistical significance (P < .0002). Mandibular ORN is a frequent long-term complication of RT for oral cavity and oropharynx cancers. Mandibular surgery before irradiation is the only independent risk factor. These aspects must be considered when planning treatment for these tumors.

Mandibular single-implant overdentures: a review with surgical and prosthodontic perspectives of a novel approach.

PubMed

Alsabeeha, Nabeel; Payne, Alan G T; De Silva, Rohana K; Swain, Michael V

2009-04-01

To review the literature on mandibular single-implant overdentures (opposing complete maxillary dentures), and present surgical and prosthodontic perspectives of a novel approach for this treatment option. An electronic search through the databases of Pubmed, Embase and Medline using the linked key words 'mandibular single implant overdentures' was performed. The search was limited to English language articles published up to August 2008. Hand searches through articles retrieved from the electronic search, peer-reviewed journals and recent conference proceedings were also conducted. A limited number of reports were identified on mandibular single-implant overdentures (opposing maxillary complete dentures). They comprised of case-series reports, short-term prospective trials and current randomized-controlled clinical trials. Different loading protocols with different implant systems have been used, but always with regular diameter implants. Specific anatomical and vascular dangers of the mandibular midline symphysis are identified including a novel surgical approach using a currently available short, wide diameter tapered implant. In addition, the prosthodontic rationale for using a larger attachment system (incorporating a platform switch) for mandibular single-implant overdentures is described. The review reveals that there is a lack of published randomized clinical trials using mandibular single-implant overdentures, opposing maxillary complete dentures. Without the evidence from randomized clinical trials, routine use of this novel approach cannot be recommended, compared with using regular diameter implants and matching attachment systems.

Mandibular movement range in children.

PubMed

Machado, Barbara Cristina Zanandréa; Medeiros, Ana Paula Magalhães; Felício, Cláudia Maria de

2009-01-01

identification of the mandibular movement range is an important procedure in the evaluation of the stomatognathic system. However, there are few studies in children that focus on normal parameters or abnormalities. to determine the average range of mandibular movements in Brazilian children aged 6 to 12 years; to verify the difference between genders, in each age group, and between the different age groups: 6-8 years; 8.1-10 years; and 10.1-12 years. participants of the study were 240 healthy children selected among regular students from local schools of São Paulo State. The maximum mandibular opening, lateral excursion and protrusive movements, and deviation of the medium line, if present, were measured using a digital caliper. Student T test, Analysis of variance and Tukey test were considered significant for p < 0.05. the mean values observed in the studied sample were: 44.51mm for maximum mandibular opening; 7.71mm for lateral excursion to the right; 7.92mm for lateral excursion to the left; 7.45mm for protrusive movements. No statistical difference was observed between genders. There was a gradual increase in the range of mandibular movements, with significant differences mainly between the ages of 6-8 years and 10.1-12 years. during childhood the range of mandibular movements increases. Age should be considered in this analysis for a greater precision in the diagnosis.

Free gingival autograft for augmentation of keratinized tissue in apical to gingival recession – A case report

PubMed Central

Anand, Vishal; Gulati, Minkle; Rastogi, Pavitra; Dixit, Jaya

2012-01-01

Background The treatment of the mucogingival problem is one of the main objectives of the periodontal therapy. The insufficient or absent attached gingiva increases the risk of development of gingival recessions. Method One patient with Miller class II gingival recession and small vestibule depth in the frontal mandibular region was selected for treatment. Autogenous free gingival grafts harvested from the palatal mucosa were used to gain the attached gingiva. Result The initial healing completed in 2 weeks without complication. The augmentation of the attached gingival tissue using the free gingival graft technique led to gain of attached gingiva in the treated regions. Conclusion The limitations of the apical mucosal flap displacement for preparation of recipient site in situations with inadequate vestibule depth and small alveolar bone height require a graft with small width. The result from the presented case report with application of the free gingival graft indicates that it could be applied when augmentation of the attached gingiva tissue. PMID:25737851

A radiographic template for a two-implant mandibular overdenture using the patient’s existing denture

PubMed Central

Huynh-Ba, G; Alexander, P; Vargas, A; Vierra, M; Oates, TW

2012-01-01

This article introduces a technique for modifying an existing mandibular complete denture for use as a radiographic template with a radiopaque light-activated calcium hydroxide (Ca(OH)2) preparation. This allows prosthetically-driven treatment planning and surgical placement of 2 implants to support the existing mandibular denture. PMID:23328197

Cerebro-costo-mandibular syndrome: Report of two cases.

PubMed

Abdalla, Wael; Panigrahy, Ashok; Bartoletti, Stefano C

2011-01-01

Cerebro-costo-mandibular syndrome (CCMS) is a rare syndrome that includes a constellation of mandibular hypoplasia and posterior rib defects as its basic features. Additional features can include hearing loss, tracheal cartilage abnormalities, scoliosis, elbow hypoplasia, and spina bifida. Here we report two cases of CCMS and discuss the reported long-term outcome of the disease.

Anatomic symmetry of root and root canal morphology of posterior teeth in Indian subpopulation using cone beam computed tomography: A retrospective study

PubMed Central

Felsypremila, Gnanasekaran; Vinothkumar, Thilla Sekar; Kandaswamy, Deivanayagam

2015-01-01

Objective: To investigate the anatomic symmetry of maxillary and mandibular posteriors in Indian subpopulation using cone beam computed tomography (CBCT). Materials and Methods: CBCT images of 246 patients that had at least one noncarious, posterior tooth free of restorations in each quadrant were enrolled for retrospective analysis. A total of 3015 teeth (811 maxillary premolars, 845 mandibular premolars, 738 maxillary molars, and 621 mandibular molars) were analyzed for number of roots and root canals, canal morphology and anatomic symmetry, and concurrent types between the maxilla and mandible. Results: There was no difference in the percentage of symmetry for maxillary first (81.5%) and second (81.5%) premolars. Mandibular second premolars (98.3%) exhibited greater symmetry than mandibular first premolars (96.1%). First molars (77.5% and 82.1%) showed greater symmetry than second molars (70.8% and 78.6%), in both maxillary and mandibular arches, respectively. The most common anatomy observed were: maxillary first premolars – 2 roots with 2 canals, maxillary second premolars – 1 root with 2 canals, mandibular first and second premolars – 1 root with 1 canal, maxillary first and second molars – 3 roots with 4 canals, and mandibular first and second molars – 2 roots with 3 canals. When compared with any other teeth, maximum asymmetry was observed in maxillary second molar (29.2%). Conclusion: The percentage of symmetry observed in the present study varied from 70% to 98% with least percentage of symmetry in maxillary second molars. These data should alert the clinicians while treating homonymous teeth of the same patient. PMID:26929687

Kinematic Modeling of Normal Voluntary Mandibular Opening and Closing Velocity-Initial Study.

PubMed

Gawriołek, Krzysztof; Gawriołek, Maria; Komosa, Marek; Piotrowski, Paweł R; Azer, Shereen S

2015-06-01

Determination and quantification of voluntary mandibular velocity movement has not been a thoroughly studied parameter of masticatory movement. This study attempted to objectively define kinematics of mandibular movement based on numerical (digital) analysis of the relations and interactions of velocity diagram records in healthy female individuals. Using a computerized mandibular scanner (K7 Evaluation Software), 72 diagrams of voluntary mandibular velocity movements (36 for opening, 36 for closing) for women with clinically normal motor and functional activities of the masticatory system were recorded. Multiple measurements were analyzed focusing on the curve for maximum velocity records. For each movement, the loop of temporary velocities was determined. The diagram was then entered into AutoCad calculation software where movement analysis was performed. The real maximum velocity values on opening (Vmax ), closing (V0 ), and average velocity values (Vav ) as well as movement accelerations (a) were recorded. Additionally, functional (A1-A2) and geometric (P1-P4) analysis of loop constituent phases were performed, and the relations between the obtained areas were defined. Velocity means and correlation coefficient values for various velocity phases were calculated. The Wilcoxon test produced the following maximum and average velocity results: Vmax = 394 ± 102, Vav = 222 ± 61 for opening, and Vmax = 409 ± 94, Vav = 225 ± 55 mm/s for closing. Both mandibular movement range and velocity change showed significant variability achieving the highest velocity in P2 phase. Voluntary mandibular velocity presents significant variations between healthy individuals. Maximum velocity is obtained when incisal separation is between 12.8 and 13.5 mm. An improved understanding of the patterns of normal mandibular movements may provide an invaluable diagnostic aid to pathological changes within the masticatory system. © 2014 by the American College of Prosthodontists.

Relationship between cervical vertebral maturation and mandibular growth.

PubMed

Ball, Gina; Woodside, Donald; Tompson, Bryan; Hunter, W Stuart; Posluns, James

2011-05-01

The cervical vertebrae have been proposed as a method of determining biologic maturity. The purposes of this study were to establish a pattern of mandibular growth and to relate this pattern to the stages of cervical vertebral maturation. Cephalometric radiographs, taken annually from ages 9 to 18 years, were evaluated for 90 boys from the Burlington Growth Center, Toronto, Ontario, Canada. Mandibular lengths were measured from articulare to gnathion, and incremental growth was determined. Cervical vertebral maturation stages were assessed by using a 6-stage method. Advanced, average, and delayed maturation groups were established. The prepubertal mandibular growth minimum velocity occurred during cervical stages 1 through 4 (P = 0.7327). Peak mandibular growth velocity occurred most frequently during stage 4 in all 3 maturation groups, with a statistical difference in the average and delayed groups (P <0.0001) and the advanced group (P = 0.0143). The average number of years spent in stage 4 was 3.79 (P <0.0001). The average amount of mandibular growth occurring during stage 4 was 9.40 mm (P <0.0001). The average amount of growth in stages 5 and 6 combined was 7.09 mm. Progression from cervical stages 1 through 6 does not occur annually; time spent in each stage varies depending on the stage and the maturation group. Cervical vertebral maturation stages cannot accurately identify the mandibular prepubertal growth minimum and therefore cannot predict the onset of the peak in mandibular growth. The cervical vertebral maturation stages should be used with other methods of biologic maturity assessment when considering both dentofacial orthopedic treatment and orthognathic surgery. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Effect of mandibular tori on glottic exposure during simulated suspension microlaryngoscopy.

PubMed

Best, Simon R; Kobler, James B; Friedman, Aaron D; Barbu, Anca M; Zeitels, Steven M; Burns, James A

2014-03-01

Mandibular tori have been identified as a contributing factor in difficult exposure during intubation. However, no investigation has measured the effect of mandibular tori on glottic exposure during suspension microlaryngoscopy (SML). The objective of this study was to measure how the size and location of mandibular tori affect glottic exposure during simulated SML at different thyromental distances. Suspension microlaryngoscopy was modeled on an anatomically accurate skull and larynx with thyromental distances between 6 and 12 cm. Mandibular tori were simulated by protruding screws 5 to 15 mm from the lingual aspect of the mandible. The tori were positioned either 15 mm (anterior) or 25 mm (posterior) from the midline of the symphysis. The glottic exposure for the various-size tori in each location was measured by recording the displacement of the glottiscope tip relative to the most anterior exposure achievable without tori. The glottiscope angle relative to the horizontal plane was measured for each condition. Mandibular tori of more than 10 mm had a significant impact on glottic exposure. Displacement of the glottiscope tip ranged from 2 to 9 mm for anteriorly placed tori and from 7 to 29 mm for posteriorly placed tori, with larger tori causing greater displacement. Increasing the thyromental distance increased the posterior glottiscope tip displacement regardless of torus size or location. The glottiscope angle increased with larger tori (12º to 28º), but this angle did not change with increasing thyromental distance. Larger size and more-posterior location of mandibular tori more significantly reduce glottic exposure during SML. The inner table of the mandible is the most relevant anatomic constraint on glottic exposure, which varies with the presence or absence of mandibular tori independent of thyromental distance.

Nonsurgical correction of a Class III malocclusion in an adult by miniscrew-assisted mandibular dentition distalization.

PubMed

Jing, Yan; Han, Xianglong; Guo, Yongwen; Li, Jingyu; Bai, Ding

2013-06-01

This article reports the successful use of miniscrews in the mandible to treat a 20-year-old Mongolian woman with a chief complaint of anterior crossbite. The patient had a skeletal Class III malocclusion with a mildly protrusive mandible, an anterior crossbite, and a deviated midline. In light of the advantages for reconstruction of the occlusal plane and distal en-masse movement of the mandibular arch, we used a multiloop edgewise archwire in the initial stage. However, the maxillary incisors were in excessive labioversion accompanied by little retraction of the mandibular incisors; these results were obviously not satisfying after 4 months of multiloop edgewise archwire treatment. Two miniscrews were subsequently implanted vertically in the external oblique ridge areas of the bilateral mandibular ramus as skeletal anchorage for en-masse distalization of the mandibular dentition. During treatment, the mandibular anterior teeth were retracted about 4.0 mm without negative lingual inclinations. The movement of the mandibular first molar was almost bodily translation. The maxillary incisors maintained good inclinations by rotating their brackets 180° along with the outstanding performance of the beta-titanium wire. The patient received a harmonious facial balance, an attractive smile, and ideal occlusal relationships. The outcome was stable after 1 year of retention. Our results suggest that the application of miniscrews in the posterior area of the mandible is an effective approach for Class III camouflage treatment. This technique requires minimal compliance and is particularly useful for correcting Class III patients with mild mandibular protrusion and minor crowding. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Ankylosis of temporomandibular joints after mandibular distraction osteogenesis in patients with Nager syndrome: Report of two cases and literature review.

PubMed

Wu, Cheng Chun; Sakahara, Daisuke; Imai, Keisuke

2017-10-01

Nager syndrome, also known as Nager acrofacial dysostosis, was first described by Nager and de Reynier in 1948. The patients commonly present with micrognathia, and a preventive tracheostomy is necessary when there are symptoms of upper airway obstruction. Mandibular distraction osteogenesis is considered as an effective procedure, which not only improves micrognathia but also minimizes the chances of tracheostomy. However, mandibular distraction osteogenesis has some complications such as relapse, teeth injury, infection, and injury of the temporomandibular joints (TMJs). In this study, the author reported two patients with Nager syndrome who suffered from ankylosis of TMJs after mandibular distraction osteogenesis. In addition, a comprehensive literature review of post-distraction ankylosis of TMJs in patients with Nager syndrome was performed. Few studies demonstrated the condition of TMJs after mandibular distraction osteogenesis, and three studies were identified from the review. One study reported ankylosis of bilateral coronoid processes, in which coronoidectomies were necessary. Another study reported the use of prostheses to replace the ankylosed joints in a patient who had undergone many surgeries of the joints, such as gap arthroplasties, reconstructions with costochondral grafts, etc. One other study raised the concept of unloading the condyles during the mandibular distraction to prevent subsequent ankylosis. It seems that multiple factors are related to the ankylosis of TMJs after mandibular distraction osteogenesis in patients with Nager syndrome. Prevention of post-distraction ankylosis of the joints is important because the treatment is difficult and not always effective. We should conduct more studies about protection of the joints during mandibular distraction in the future. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Airway and Feeding Outcomes of Mandibular Distraction, Tongue-Lip Adhesion, and Conservative Management in Pierre Robin Sequence: A Prospective Study.

PubMed

Khansa, Ibrahim; Hall, Courtney; Madhoun, Lauren L; Splaingard, Mark; Baylis, Adriane; Kirschner, Richard E; Pearson, Gregory D

2017-04-01

Pierre Robin sequence is characterized by mandibular retrognathia and glossoptosis resulting in airway obstruction and feeding difficulties. When conservative management fails, mandibular distraction osteogenesis or tongue-lip adhesion may be required to avoid tracheostomy. The authors' goal was to prospectively evaluate the airway and feeding outcomes of their comprehensive approach to Pierre Robin sequence, which includes conservative management, mandibular distraction osteogenesis, and tongue-lip adhesion. A longitudinal study of newborns with Pierre Robin sequence treated at a pediatric academic medical center between 2010 and 2015 was performed. Baseline feeding and respiratory data were collected. Patients underwent conservative management if they demonstrated sustainable weight gain without tube feeds, and if their airway was stable with positioning alone. Patients who required surgery underwent tongue-lip adhesion or mandibular distraction osteogenesis based on family and surgeon preference. Postoperative airway and feeding data were collected. Twenty-eight patients with Pierre Robin sequence were followed prospectively. Thirty-two percent had a syndrome. Ten underwent mandibular distraction osteogenesis, eight underwent tongue-lip adhesion, and 10 were treated conservatively. There were no differences in days to extubation or discharge, change in weight percentile, requirement for gastrostomy tube, or residual obstructive sleep apnea between the three groups. No patients required tracheostomy. The greatest reduction in apnea-hypopnea index occurred with mandibular distraction osteogenesis, followed by tongue-lip adhesion and conservative management. Careful selection of which patients with Pierre Robin sequence need surgery, and of the most appropriate surgical procedure for each patient, can minimize the need for postprocedure tracheostomy. A comprehensive approach to Pierre Robin sequence that includes conservative management, mandibular distraction osteogenesis, and tongue-lip adhesion can result in excellent airway and feeding outcomes. Therapeutic, II.

Mandibular movement during sleep bruxism associated with current tooth attrition.

PubMed

Okura, Kazuo; Shigemoto, Shuji; Suzuki, Yoshitaka; Noguchi, Naoto; Omoto, Katsuhiro; Abe, Susumu; Matsuka, Yoshizo

2017-01-01

Observation of attrition patterns suggests that mandibular movement in sleep bruxism (SB) may be associated with current tooth attrition. The aim of this study was to confirm this phenomenon by investigating mandibular movement and masseter muscle activity. The subject was a healthy 21-year-old Japanese male. We recorded biological signals including mandibular movement and masseter electromyograms (EMGs) with a polysomnograph. Based on the EMG using Okura's criteria, SB events were classified into clenching, grinding and mixed types according to mandibular movement criteria. The close-open mandibular movement cycles (CO-cycles) during grinding and mixed type events were selected based on mandibular movement trajectories. Fifty-eight CO-cycles were selected in seven grinding and three mixed types. We found that SB mandibular movements associated with current tooth attrition. Excessive lateral movements (ELM) beyond the canine edge-to-edge position were observed in the closing (10.3%) and opening (13.8%) phases of the CO-cycle. Total masseter muscle activity was significantly higher during voluntary grinding (VGR) than during CO-cycle including ELM (working side: P=0.036, balancing side: P=0.025). However, in the middle and late parts of the opening phase, working side masseter muscle activity was significantly higher during CO-cycle including ELM than during VGR (P=0.012). In the early part of the closing phase, balancing side masseter muscle activity was significantly higher during CO-cycle including ELM than during VGR (P=0.017). These findings suggest that excessive forceful grinding during ongoing SB events may have caused canine attrition in this patient. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Internal and external morphology of mandibular molars: An original micro-CT study and meta-analysis with review of implications for endodontic therapy.

PubMed

Tomaszewska, Iwona M; Skinningsrud, Bendik; Jarzębska, Anna; Pękala, Jakub R; Tarasiuk, Jacek; Iwanaga, Joe

2018-03-25

The aim of this radiological micro-CT study and meta-analysis was to determine the morphological features of the root canal anatomy of the mandibular molars. The radiological study included micro-CT scans of 108 mandibular first, 120 mandibular second, and 146 mandibular third molars. For our meta-analysis, an extensive search was conducted through PubMed, Embase, and Web of Science to identify articles eligible for inclusion. Data extracted included investigative method (cadaveric, intraoperative, or imaging), Vertucci type of canal configuration, presence/number of canals, roots, apical foramina, apical deltas, and intercanal communications. In the mesial roots of mandibular molars, the most frequent Vertucci type of canal configuration was type IV, except for the mandibular third molar where type I was most common. Type I was most common in the distal root. There were usually two canals in the mesial root and one in the distal root. Two was the most common number of roots, and a third root was most prevalent in Asia. One apical foramen was most common in the distal root and two apical foramina in the mesial root. Intercanal communications were most frequent in the mesial root. Knowledge of the complex anatomy of the mandibular molars can make root canal therapy more likely to succeed. We recommend the use of cone-beam computed tomography before and after endodontic treatment to enable the root anatomy to be accurately described and properly diagnosed, and treatment outcome to be assessed. Clin. Anat. 00:000-000, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Penetration of flomoxef into human maxillary and mandibular bones.

PubMed

Igawa, H H; Sugihara, T; Yoshida, T; Kawashima, K; Ohura, T

1995-09-01

Penetration of flomoxef into the maxillary and mandibular bones was assayed clinically to provide data about its usefulness for the prevention of postoperative infection after maxillofacial surgery. Twenty-one patients undergoing maxillofacial surgery at our department were given flomoxef 2 g dissolved in 20 ml of physiological saline intravenously over 3 minutes during operation, and the serum, maxillary and mandibular concentrations were measured 1, 3, and 6 hours after injection by the band culture method using Escherichia coli 7437 as the indicator strain. The mean concentrations were 53.4, 16.1, and 2.6 micrograms/ml, respectively, in the serum, 17.6, 7.8, and 1.0 micrograms/g in maxillary bone, and 16.4, 4.2, and 0.9 micrograms/g in mandibular bone. The mean bone:serum ratios at 1, 3, and 6 hours were 33.0%, 48.2%, and 36.8%, respectively, for maxillary bone, and 30.7%, 26.2%, and 35.7% for mandibular bone. When compared with previously reported data on the bone:serum ratios in jaw of various other intravenous antibiotics, our results show that penetration of flomoxef into maxillary and mandibular bone is extremely high. As all the intramaxillary and intramandibular concentrations exceed its MIC80 values against clinical isolates of bacteria frequently isolated in cases of infection in the oral and maxillofacial region, it is apparent that one intravenous shot of flomoxef 2 g allows penetration of the drug into the maxillary and mandibular bones at effective concentrations. Flomoxef is therefore potentially useful for the prevention and treatment of infections in the oral and maxillofacial region, as it has excellent penetration into the maxillary and mandibular bones.

Morphologic evaluation of dentoalveolar structures of mandibular anterior teeth during augmented corticotomy-assisted decompensation.

PubMed

Ahn, Hyo-Won; Seo, Dong-Hwi; Kim, Seong-Hun; Park, Young-Guk; Chung, Kyu-Rhim; Nelson, Gerald

2016-10-01

Our aim in this study was to evaluate the effect of augmented corticotomy on the decompensation pattern of mandibular anterior teeth, alveolar bone, and surrounding periodontal tissues during presurgical orthodontic treatment. Thirty skeletal Class III adult patients were divided into 2 groups according to the application of augmented corticotomy labial to the anterior mandibular roots: experimental group (with augmented corticotomy, n = 15) and control group (without augmented corticotomy, n = 15). Lateral cephalograms and cone-beam computed tomography images were taken before orthodontic treatment and before surgery. The measurements included the inclination and position of the mandibular incisors, labial alveolar bone area, vertical alveolar bone height, root length, and alveolar bone thickness at 3 levels surrounding the mandibular central incisors, lateral incisors, and canines. The mandibular incisors were significantly proclined in both groups (P <0.001); however, the labial movement of the incisor tip was greater in the experimental group (P <0.05). Significant vertical alveolar bone loss was observed only in the control group (P <0.001). The middle and lower alveolar thicknesses and labial alveolar bone area increased in the experimental group. In the control group, the upper and middle alveolar thicknesses and labial alveolar bone area decreased significantly. There were no significant differences in dentoalveolar changes between the 3 kinds of anterior teeth in each group, except for root length in the experimental group (P <0.05). Augmented corticotomy provided a favorable decompensation pattern of the mandibular incisors, preserving the periodontal structures surrounding the mandibular anterior teeth for skeletal Class III patients. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

A model of mandibular movements during speech: normative pilot study for the Brazilian Portuguese language.

PubMed

Bianchini, Esther M G; de Andrade, Cláudia R F

2006-07-01

The precision of speech articulation is related to the possibility and freedom of the mandibular movements, modifying the spaces in order to allow the different articulatory positions of each sound. Electrognathography allows the objective delineation and registration of the mandibular movements, determining the level of opening, translations and velocity of these movements. Its use is a resource that can establish quantitative diagnostic parameters. The aim of this study was to verify the amplitude, velocity and characterization of the mandibular movements during speech using computerized electrognathography. Participants were 40 adults, male and female, with no temporomandibular disorders; with no missing teeth; with no dental occlusion alterations or dentofacial deformities; with no dental prostheses; and with no communication, neurological or cognitive deficits. The mandibular movements were observed during the sequential naming of pictures containing all the phonemes of the Brazilian Portuguese language. The registrations were obtained using electrognathography (BioENG-BioPak system), assessing the spatial position, course and velocity of the mandibular movements. The mean values of velocity were: 88.65 mm/sec during opening and 89.90mm/sec during closing. The mean values of amplitude were: sagittal opening: 12.77 mm, frontal opening: 11.21 mm, protrusion: 1.22 mm; retrusion 5.67 mm; translations to the right: 1.49 mm and to the left: 1.59 mm. The velocity of opening is directly related to that of closing. The amplitude of opening demonstrates a direct correlation with the velocity of opening and closing. All participants presented lateral translations during the course of the jaw. The assessment of speech in normal individuals is characterized by: discreet mandibular movements with an anteroposterior component and lateral translations. This study allowed for the delineation of a profile of the mandibular movements during speech in asymptomatic individuals.

Deoxycholic Acid and the Marginal Mandibular Nerve: A Cadaver Study.

PubMed

Blandford, Alexander D; Ansari, Waseem; Young, Jason M; Maley, Bruce; Plesec, Thomas P; Hwang, Catherine J; Perry, Julian D

2018-06-04

One of the rare but serious complications observed with deoxycholic acid administration is damage to the marginal mandibular nerve. In this study, we evaluated if deoxycholic acid directly induces histologic damage to fresh cadaveric marginal mandibular nerve. A segment of marginal mandibular nerve was harvested from 12 hemifaces of 6 fresh cadavers. The nerve specimen was exposed to either 0.9% sterile saline for 24 h, deoxycholic acid (10 mg/ml) for 20 min, or deoxycholic acid (10 mg/ml) for 24 h. The nerve specimens were then fixed in glutaraldehyde for a minimum of 24 h. Toluidine blue stained sections were evaluated for stain intensity using light microscopy and color deconvolution image analysis. Supraplatysmal fat was harvested as a positive control and exposed to the same treatments as the marginal mandibular nerve specimens, then evaluated using transmission electron microscopy. Toluidine blue staining was less in the marginal mandibular nerve exposed to deoxycholic acid when compared to saline. The specimen exposed to deoxycholic acid for 24 h showed less toluidine blue staining than that of the nerve exposed to deoxycholic acid for 20 min. Transmission electron microscopy of submental fat exposed to deoxycholic acid revealed disruption of adipocyte cell membrane integrity and loss of cellular organelles when compared to specimens only exposed to saline. Deoxycholic acid (10 mg/ml) damages the marginal mandibular nerve myelin sheath in fresh human cadaver specimens. Direct deoxycholic acid neurotoxicity may cause marginal mandibular nerve injury clinically. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Longitudinal observation of basic mandibular movements: report of a case.

PubMed

Hayasaki, H; Okamoto, A; Nakata, S; Yamasaki, Y; Nakata, M

2003-01-01

Sound development of mandibular function during childhood is indispensable to establishing healthy function in adults. To examine this developmental process, longitudinal recordings of basic mandibular movements were done using an optoelectronic analysis. Mandibular movements were recorded on five separate occasions in one boy, from an age of six years and five months to 14 years and five months. The incisor pathways during protrusion and lateral excursion were initially shallow, with more anterior than inferior movement, but as he grew the amount of inferior movement and the amount of rotation both increased. Similarly, at his first recording there was very little hinge-like rotation during mouth closing, but rotation increased markedly after eruption of his permanent second molars. These findings suggest that mandibular movements change from being relatively simple with more translation in younger children to more complex movements with more rotation once the permanent dentition is established.

Alveolar ridge expansion-assisted orthodontic space closure in the mandibular posterior region.

PubMed

Ozer, Mete; Akdeniz, Berat Serdar; Sumer, Mahmut

2013-12-01

Orthodontic closure of old, edentulous spaces in the mandibular posterior region is a major challenge. In this report, we describe a method of orthodontic closure of edentulous spaces in the mandibular posterior region accelerated by piezoelectric decortication and alveolar ridge expansion. Combined piezosurgical and orthodontic treatments were used to close 14- and 15-mm-wide spaces in the mandibular left and right posterior areas, respectively, of a female patient, aged 18 years and 9 months, diagnosed with skeletal Class III malocclusion, hypodontia, and polydiastemas. After the piezoelectric decortication, segmental and full-arch mechanics were applied in the orthodontic phase. Despite some extent of root resorption and anchorage loss, the edentulous spaces were closed, and adequate function and esthetics were regained without further restorative treatment. Alveolar ridge expansion-assisted orthodontic space closure seems to be an effective and relatively less-invasive treatment alternative for edentulous spaces in the mandibular posterior region.

Mandibular reconstruction using fibula free flap harvested using a customised cutting guide: how we do it.

PubMed

Tarsitano, A; Ciocca, L; Cipriani, R; Scotti, R; Marchetti, C

2015-06-01

Free fibula flap is routinely used for mandibular reconstructions. For contouring the flap, multiple osteotomies should be shaped to reproduce the native mandibular contour. The bone segments should be fixed using a reconstructive plate. This plate is usually manually bent by the surgeon during surgery. This method is efficient, but during reconstruction it is complicated to reproduce the complex 3D conformation of the mandible and recreate a normal morphology with a mandibular profile as similar as possible to the original; any aberration in its structural alignment may lead to aesthetic and function alterations due to malocclusion or temporomandibular disorders. In order to achieve better morphological and functional outcomes, we have performed a customised flap harvest using cutting guides. This study demonstrates how we have performed customised mandibular reconstruction using CAD-CAM fibular cutting guides in 20 patients undergoing oncological segmental resection.

Variations in the branching pattern of posterior division of mandibular nerve: a case report.

PubMed

Muraleedharan, Aparna; Veeramani, Raveendranath; Chand, Parkash

2014-11-01

Abnormal communications among the branches of mandibular nerve especially the posterior division are significant due to various procedures undertaken in this region. These variations are worth reporting as they pose serious implications in several interventions in this region, and may even lead to false diagnosis. During routine dissection, the mandibular nerve and its branches were dissected in the infratemporal fossa. The branches from the posterior division of the mandibular nerve namely the inferior alveolar and auriculotemporal nerves were carefully dissected, and their abnormal branching pattern was noted. There was a communicating branch between left inferior alveolar and auriculotemporal nerve. There was also a variant recurrent branch from the left inferior alveolar nerve that supplied the lateral pterygoid muscle. Such variant branches and communications between the branches of mandibular nerve as seen in this case have an embryological basis and are clinically important in this region especially for dental surgeries and anesthesia.

Alveolar ridge expansion-assisted orthodontic space closure in the mandibular posterior region

PubMed Central

Akdeniz, Berat Serdar; Sumer, Mahmut

2013-01-01

Orthodontic closure of old, edentulous spaces in the mandibular posterior region is a major challenge. In this report, we describe a method of orthodontic closure of edentulous spaces in the mandibular posterior region accelerated by piezoelectric decortication and alveolar ridge expansion. Combined piezosurgical and orthodontic treatments were used to close 14- and 15-mm-wide spaces in the mandibular left and right posterior areas, respectively, of a female patient, aged 18 years and 9 months, diagnosed with skeletal Class III malocclusion, hypodontia, and polydiastemas. After the piezoelectric decortication, segmental and full-arch mechanics were applied in the orthodontic phase. Despite some extent of root resorption and anchorage loss, the edentulous spaces were closed, and adequate function and esthetics were regained without further restorative treatment. Alveolar ridge expansion-assisted orthodontic space closure seems to be an effective and relatively less-invasive treatment alternative for edentulous spaces in the mandibular posterior region. PMID:24396740

Endodontic management of middle mesial canal of the mandibular molar

PubMed Central

Sundaresh, K J; Srinivasan, Raghu; Mallikarjuna, Rachappa; Rajalbandi, Sandeep

2013-01-01

Thorough knowledge of root canal morphology and unusual anatomy of the tooth is critical for successful endodontic treatment. Although the most common configuration is two roots and three root canals, mandibular molars might have many different combinations. In the literature, it is less described about three mesial canals and two distal canals in mandibular second molars, indicating a rare anatomical configuration. A case of unusual root canal morphology is presented to demonstrate anatomical variations in mandibular molars. Endodontic therapy was performed in a mandibular second molar with five separate canals, three mesial and two distal. This report points out the importance of looking for additional canals and unusual canal morphology, because knowledge of their existence might occasionally enable clinicians to treat a case successfully that otherwise might have ended in failure. In conclusion, every attempt should be made to find and treat all root canals of a tooth. PMID:23349182

Abnormalities of the axial and proximal appendicular skeleton in adults with Laron syndrome (growth hormone insensitivity).

PubMed

Kornreich, L; Konen, O; Schwarz, M; Siegel, Y; Horev, G; Hershkovitz, I; Laron, Z

2008-02-01

To investigate abnormalities in the skeleton (with the exclusion of the skull, cervical spine, hands and feet) in patients with Laron syndrome, who have an inborn growth hormone resistance and congenital insulin-like growth factor-1 (IGF-1) deficiency. The study group was composed of 15 untreated patients with Laron syndrome (seven male and eight female) aged 21-68 years. Plain films of the axial and appendicular skeleton were evaluated retrospectively for abnormalities in structure and shape. The cortical width of the long bones was evaluated qualitatively and quantitatively (in the upper humerus and mid-femur), and the cortical index was calculated and compared with published references. Measurements were taken of the mid-anteroposterior and cranio-caudal diameters of the vertebral body and spinous process at L3, the interpedicular distance at L1 and L5, and the sacral slope. Thoracic and lumbar osteophytes were graded on a 5-point scale. Values were compared with a control group of 20 healthy persons matched for age. The skeleton appeared small in all patients. No signs of osteopenia were visible. The cortex of the long bones appeared thick in the upper limbs in 11 patients and in the lower limbs in four. Compared with the reference values, the cortical width was thicker than average in the humerus and thinner in the femur. The vertebral diameters at L3 and the interpedicular distances at L1 and L5 were significantly smaller in the patients than in the control subjects (P<0.001); however, at L5 the canal was wider, relative to the vertebral body. The study group had a higher rate of anterior osteophytes in the lumbar spine than the controls had, and their osteophytes were also significantly larger. In the six patients for whom radiographs of the upper extremity in its entirety were available on one film, the ulna appeared to be rotated. In one 22-year-old man, multiple epiphyses were still open. Congenital IGF-1 deficiency leads to skeletal abnormalities characterized by small bones, narrow spinal canal, and delayed bone age. The limitation in elbow distensibility common to patients with Laron syndrome may be related to a marked retroversion of the humeral head.

Utah optrode array customization using stereotactic brain atlases and 3-D CAD modeling for optogenetic neocortical interrogation in small rodents and nonhuman primates.

PubMed

Boutte, Ronald W; Merlin, Sam; Yona, Guy; Griffiths, Brandon; Angelucci, Alessandra; Kahn, Itamar; Shoham, Shy; Blair, Steve

2017-10-01

As the optogenetic field expands, the need for precise targeting of neocortical circuits only grows more crucial. This work demonstrates a technique for using Solidworks ® computer-aided design (CAD) and readily available stereotactic brain atlases to create a three-dimensional (3-D) model of the dorsal region of area visual cortex 4 (V4D) of the macaque monkey ( Macaca fascicularis ) visual cortex. The 3-D CAD model of the brain was used to customize an [Formula: see text] Utah optrode array (UOA) after it was determined that a high-density ([Formula: see text]) UOA caused extensive damage to marmoset ( Callithrix jacchus ) primary visual cortex as assessed by electrophysiological recording of spiking activity through a 1.5-mm-diameter through glass via. The [Formula: see text] UOA was customized for optrode length ([Formula: see text]), optrode width ([Formula: see text]), optrode pitch ([Formula: see text]), backplane thickness ([Formula: see text]), and overall form factor ([Formula: see text]). Two [Formula: see text] UOAs were inserted into layer VI of macaque V4D cortices with minimal damage as assessed in fixed tissue cytochrome oxidase staining in nonrecoverable surgeries. Additionally, two [Formula: see text] arrays were implanted in mice ( Mus musculus ) motor cortices, providing early evidence for long-term tolerability (over 6 months), and for the ability to integrate the UOA with a Holobundle light delivery system toward patterned optogenetic stimulation of cortical networks.

Regional structural characteristics of bovine periodontal ligament samples and their suitability for biomechanical tests.

PubMed

Bosshardt, Dieter D; Bergomi, Marzio; Vaglio, Giovanna; Wiskott, Anselm

2008-03-01

Mechanical testing of the periodontal ligament requires a practical experimental model. Bovine teeth are advantageous in terms of size and availability, but information is lacking as to the anatomy and histology of their periodontium. The aim of this study, therefore, was to characterize the anatomy and histology of the attachment apparatus in fully erupted bovine mandibular first molars. A total of 13 teeth were processed for the production of undecalcified ground sections and decalcified semi-thin sections, for NaOH maceration, and for polarized light microscopy. Histomorphometric measurements relevant to the mechanical behavior of the periodontal ligament included width, number, size and area fraction of blood vessels and fractal analysis of the two hard-soft tissue interfaces. The histological and histomorphometric analyses were performed at four different root depths and at six circumferential locations around the distal and mesial roots. The variety of techniques applied provided a comprehensive view of the tissue architecture of the bovine periodontal ligament. Marked regional variations were observed in width, surface geometry of the two bordering hard tissues (cementum and alveolar bone), structural organization of the principal periodontal ligament connective tissue fibers, size, number and numerical density of blood vessels in the periodontal ligament. No predictable pattern was observed, except for a statistically significant increase in the area fraction of blood vessels from apical to coronal. The periodontal ligament width was up to three times wider in bovine teeth than in human teeth. The fractal analyses were in agreement with the histological observations showing frequent signs of remodeling activity in the alveolar bone - a finding which may be related to the magnitude and direction of occlusal forces in ruminants. Although samples from the apical root portion are not suitable for biomechanical testing, all other levels in the buccal and lingual aspects of the mesial and distal roots may be considered. The bucco-mesial aspect of the distal root appears to be the most suitable location.

Non-extraction treatment of a Class III skeletal case.

PubMed

Gonzalez, Bulmario

2009-01-01

Adult Class III Skeletal treatment options have generally included some form of surgery (Maxillary advancement in midface deficient cases and/or Mandibular set-back). This article discusses non-surgical treatment of an adult patient using the combined concepts of mandibular molar distalization enhanced with TADs and non-extraction camouflage dental correction through maxillary incisor protraction and mandibular incisor lingualization.

Correlation between mandibular gland secretion and cuticular hydrocarbons in the stingless bee Melipona quadrifasciata.

PubMed

Cruz-Landim, C; Ferreira-Caliman, M J; Gracioli-Vitti, L F; Zucchi, R

2012-04-19

We investigated whether Melipona quadrifasciata worker mandibular gland secretions contribute directly to their cuticular hydrocarbon profile. The mandibular gland secretion composition and cuticular surface compounds of newly emerged worker bees, nurse bees, and foragers were determined by gas chromatography and mass spectrometry and compared. Both the mandibular gland secretions and the cuticular surface compounds of all worker stages were found to be composed almost exclusively of hydrocarbons. Although the relative proportion of hydrocarbons from the cuticular surface and gland secretion was statistically different, there was a high similarity in the qualitative composition between these structures in all groups of bees.

Class III malocclusion treated with distalization of the mandibular dentition with miniscrew anchorage: A 2-year follow-up.

PubMed

Chen, Kun; Cao, Yang

2015-12-01

This case report describes the orthodontic camouflage treatment for a 16-year-old Chinese girl with a Class III malocclusion. The treatment included extractions of the mandibular second molars, fixed appliance therapy, and miniscrew-aided mandibular arch distalization. Pretreatment, posttreatment, and 2-year follow-up records are shown. The anterior negative overjet and the Class III molar and canine relationships were corrected. The patient's facial profile was greatly improved. The mandibular third molars erupted into the second molar spaces, with acceptable intercuspation with the maxillary dentition. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Clinical efficacy of open reduction and semirigid internal fixation in management of displaced pediatric mandibular fractures: a series of 10 cases and surgical guidelines.

PubMed

Joshi, Samir; Kshirsagar, Rajesh; Mishra, Akshay; Shah, Rahul

2015-01-01

To evaluate the efficacy of open reduction and semirigid internal fixation in the management of displaced pediatric mandibular fractures. Ten patients with displaced mandibular fractures treated with 1.5 mm four holed titanium mini-plate and 4 mm screws which were removed within four month after surgery. All cases showed satisfactory bone healing without any growth disturbance. Open reduction and rigid internal fixation (ORIF) with 1.5 mm titanium mini- plates and 4 mm screws is a reliable and safe method in treatment of displaced paediatric mandibular fractures.

Dislocation of the mandibular condyle into the middle cranial fossa causing an epidural haematoma.

PubMed

Struewer, Johannes; Kiriazidis, Ilias; Figiel, Jens; Dukatz, Thomas; Frangen, Thomas; Ziring, Ewgeni

2012-07-01

Dislocation of the mandibular condyle into the middle cranial fossa is a rare complication of mandibular trauma due to anatomical and biomechanical factors. Owing to the proximity of the temporal glenoid fossa to the middle meningeal artery, there is the risk of serious sequelae in case of trauma. The authors report the case of a 36-year-old male patient, who was beaten up in a family dispute and presented with complex mandibular and maxillofacial fractures, including mandibular condyle intrusion into the middle cranial fossa causing extensive meningeal bleeding. The patient underwent immediate surgery, with evacuation of the epidural haematoma via a temporal approach. In addition open reduction and reconstruction of the temporal glenoid fossa via anatomic reduction of the fragments was performed. A functional occlusion was re-established via miniplate reconstruction of the complex mandibular body and ramus fractures. Prompt diagnosis and a multidisciplinary approach are essential to minimize the complications. Advanced imaging modalities of computed tomography are indicated. Treatment options should be individualized in particular in case of suspected neurological injury. Copyright © 2011 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Evaluation of skeletal and dental age using third molar calcification, condylar height and length of the mandibular body

PubMed Central

Kedarisetty, Sunil Gupta; Rao, Guttikonda Venkateswara; Rayapudi, Naveen; Korlepara, Rajani

2015-01-01

Aim: To identify the most reliable method for age estimation among three variables, that is, condylar height, length of mandibular body and third molar calcification by Demirjian's method. Materials and Methods: Orthopantomograms and lateral cephalograms of 60 patients with equal gender ratio were included in the study, among each gender 15 subjects were below 18 years and 15 subjects were above 18 years. Lateral cephalograms were traced, height of condyle and mandibular body are measured manually on the tracing paper, OPG's were observed on radiographic illuminator and maturity score of third molar calcification was noted according to Demirjian's method. All the measurements were subjected to statistical analysis. Results: The results obtained are of no significant difference between estimated age and actual age with all three parameters (P > 0.9780 condylar height, P > 0.9515 length of mandibular body, P > 0.8611 third molar calcification). Among these three, length of mandibular body shows least standard error test (i.e. 0.188). Conclusion: Although all three parameters can be used for age estimation, length of mandibular body is more reliable followed by height of condyle and third molar calcification. PMID:26005300

PubMed Central

BOLZONI, A.; MAPELLI, A.; BAJ, A.; SIDEQUERSKY, F.V; GIANNÌ, A.B.

2015-01-01

SUMMARY Seven patients who underwent mandibular reconstruction with a fibula free flap (one on the midline, six on either right or left side) and were rehabilitated with implant supported prostheses, performed free mandibular border movements (maximal mouth opening and closing, right and left lateral excursions, protrusion) that were recorded by a non-invasive motion analyser. Temporomandibular joint (TMJ) kinematic parameters were compared to those calculated in healthy control subjects using z-scores. Maximum mouth opening was reduced in all patients, with z-scores ranging from -2.742 to -0.106, and performed with a reduced sagittal plane mandibular rotation. Interincisal point forward movement during protrusion was reduced in all but one patient. Lateral mandibular movements (displacement of the interincisal point) and bilateral condylar movements during mouth opening were very variable and sometimes asymmetrical. Mandibular rotation was also variable, with z-scores ranging from -1.265 to 1.388. Together with mandibular range of motion, we investigated biomechanical characteristics of TMJ motion that can provide further information about the joint without submitting the patient to harmful procedures, and that can be followed-up during healing. The investigation indicates those areas that need to be given special attention in preoperative planning, patient information and rehabilitation. PMID:26900241

Roles of FGFR3 during morphogenesis of Meckel's cartilage and mandibular bones

PubMed Central

Havens, Bruce A.; Velonis, Dimitris; Kronenberg, Mark S.; Lichtler, Alex C.; Oliver, Bonnie; Mina, Mina

2008-01-01

To address the functions of FGFR2 and FGFR3 signaling during mandibular skeletogenesis, we over-expressed in the developing chick mandible, replication-competent retroviruses carrying truncated FGFR2c or FGFR3c that function as dominant negative receptors (RCAS-dnFGFR2 and RCAS-dnFGFR3). Injection of RCAS-dnFGFR3 between HH15−20 led to reduced proliferation, increased apoptosis, and decreased differentiation of chondroblasts in Meckel's cartilage. These changes resulted in the formation of a hypoplastic mandibular process and truncated Meckel's cartilage. This treatment also affected the proliferation and survival of osteoprogenitor cells in osteogenic condensations, leading to the absence of five mandibular bones on the injected side. Injection of RCAS-dnFGFR2 between HH15−20 or RCAS-dnFGFR3 at HH26 did not affect the morphogenesis of Meckel's cartilage but resulted in truncations of the mandibular bones. RCAS-dnFGFR3 affected the proliferation and survival of the cells within the periosteum and osteoblasts. Together these results demonstrate that FGFR3 signaling is required for the elongation of Meckel's cartilage and FGFR2 and FGFR3 have roles during intramembranous ossification of mandibular bones. PMID:18339367

Root and canal morphology of mandibular third molars in an Iranian population.

PubMed

Kuzekanani, Maryam; Haghani, Jahangir; Nosrati, Hossein

2012-01-01

A through knowledge of the root canal morphology is required for successful endodontic ther-apy. The aim of this study was to investigate the root and canal morphology of mandibular third molars in Kerman, a prov-ince in southeast of Iran. One-hundred-fifty extracted mandibular third molars were collected randomly from different dental clinics in Kerman. The root canal anatomy and morphology of each tooth was carefully studied using a clearing tech-nique. Root number and morphology, number of canals per root, root canal configuration according to Vertucci classifica-tion, and incidence of dilacerated roots and C-shaped canals in mandibular third molars were evaluated under stereomicro-scope with ×2 to ×3 magnifications. From the total of 150 mandibular third molars studied, 21% had one root. The majority of teeth (73%) had two roots. 5.5% of the teeth had three roots. The incidence of C-shaped canal was 3.5% in this study and 8% of the teeth had at least one dilacerated root. Although root canal anatomy and morphology of mandibular third molars is very variable having two roots seems to be the normal anatomy for these teeth.

Evaluation of the root and canal morphology of mandibular permanent molars in a south-eastern Turkish population using cone-beam computed tomography

PubMed Central

Nur, Bilge Gulsum; Ok, Evren; Altunsoy, Mustafa; Aglarci, Osman Sami; Colak, Mehmet; Gungor, Enes

2014-01-01

Objective: The aim of this retrospective study was to determine the root and canal morphology of the mandibular first and second permanent molars in a Turkish population using cone-beam computed tomography (CBCT). Materials and Methods: CBCT images of mandibular first (n = 966) and second molar (n = 1165) teeth from 850 Turkish patients were evaluated. The root canal configurations were classified according to the method of Vertucci. The data were analyzed by Pearson's Chi-square test. Results: The majority of mandibular molars were two rooted with three canals; however, three roots were identified in 0.05% of the first molars and 0.01% of the second molars, and 100% of the additional root canals were of type I configuration. Mesial roots had more complex canal systems with more than one canal, whereas most distal roots had a type I configuration. Conclusions: Within the limitations of this study, it can be concluded that CBCT scanning provides supplemental information about the root canal configurations of mandibular molars in a Turkish population. This study may help clinicians in the root canal treatment of mandibular molars. PMID:24966763

[Long-term follow-up study of titanium implant impact on pediatric mandibular growth and development].

PubMed

Hu, Yun; Li, Wei; Chen, Qi; Song, Fumin; Tang, Wei; Wang, Hang

2015-08-01

To explore the impact of titanium implant on the growth and development of pediatric mandible after suffering from mandibular fracture and undergoing open reduction and internal fixation (ORIF) compared with those that underwent titanium plate removal postoperatively. Fifteen pediatric patients with mandibular fracture who underwent ORIF were included in this study. Eight patients did not undergo titanium implant removal postoperatively, whereas the other seven patients underwent the routine. The postoperative data of the pediatrics were collected for comparative analysis by taking the patients' frontal and lateral photos, recording the inter-incisor distance, and measuring the height of mandibular ramus, length of the mandibular body, and combined length of the mandible in three-dimensional reconstruction image. All patients had acceptable facial contour, mouth opening, and occlusion, without obvious abnormalities. The radiography showed no significant difference between the bilateral mandibular lengths in the two groups of patients (P>0.05). The titanium plants have no significant impact on the growth and development of pediatric mandible postoperatively; hence, the question on whether the titanium plates should be removed or not may be neglected. The removal operation may lead to secondary trauma; thus, performing titanium plate removal routinely is not recommended.

INTERNAL ROOT MORPHOLOGY IN MANDIBULAR FIRST PERMANENT MOLARS IN A KENYAN POPULATION.

PubMed

Muriithi, N J; Maina, S W; Okoth, J; Gathece, L W

2012-05-01

To determine the internal root morphology and gender variations in mandibular first permanent molars in a Kenyan population. In vitro descriptive cross sectional study. School of Dental Sciences, University of Nairobi The mesial root of mandibular first molars had two canals in 96.3% of the teeth in both males and females and-type IV canal configuration was most prevalent in the mesial root. The distal root of the mandibular first molar had one canal in 57.7% of the teeth in males and females. There were significant gender variations in the number of canals and canal configurations in the distal root. Two canals were more prevalent in females (53.6%) compared to males (30.4%) and a single canal was more frequent in males (69.6%) compared to females (46.4%) (P=0.001). Canal types 1, 11 and IV were the most frequent in the mandibular distal root. The gender variation in the frequency of canal types I, II and IV in the distal root was statistically significant (P=0.001). Most of the mandibular first molars have three canals (56%). Two canals in the distal root are more frequent among females (53.6%) compared to males (30.4%).

Fibular free flap reconstruction for the management of advanced bilateral mandibular osteoradionecrosis.

PubMed

Shan, Xiao-Feng; Li, Ru-Huang; Lu, Xu-Guang; Cai, Zhi-Gang; Zhang, Jie; Zhang, Jian-Guo

2015-03-01

Fibular osteoseptocutaneous flap has been widely used for unilateral mandibular reconstruction. However, reports about the effects of fibular osteoseptocutaneous flap for the reconstruction of bilateral mandibular defects are limited. In this study, we used free vascularized fibular flaps to successfully manage bilateral mandibular osteoradionecrosis(ORN) in 5 patients. Functional aspects were evaluated during the reconstruction process. All 5 patients had bilateral refractory ORN of the mandible and underwent radical resection between 2003 and 2011. The reconstruction surgery was performed in 2 stages using 2 free fibular flaps in 3 patients. In the other 2 patients, reconstruction was performed in a single stage using 2 separate flaps prepared from a single fibula. All patients had a healthy mandibular symphysis and meniscus of the temporomandibular joint, and these structures were preserved during the reconstruction.Of the 10 defects involving the mandible sides, 9 were successfully reconstructed. One microvascular composite flap failed because of radiation injury to the arterial endothelium at the recipient site. After the treatments, all patients had good esthetic and functional outcomes. Preoperative clinical features such as trismus and dysphagia were also markedly improved. Our surgical method may be an effective alternative for the clinical management of advanced bilateral mandibular ORN.

Delayed dental maturity in dentitions with agenesis of mandibular second premolars.

PubMed

Daugaard, S; Christensen, I J; Kjaer, I

2010-11-01

To evaluate dental maturity in the mandibular canine/premolar and molar innervation fields in children with agenesis of the 2nd mandibular premolar and to associate these findings with normal control material. Department of Orthodontics, Institute of Odontology, University of Copenhagen. Eighty-three panoramic radiographs (27 girls and 31 boys with agenesis of one mandibular 2nd premolar and 17 girls and eight boys with agenesis of both mandibular 2nd premolars) represented all mandibular second premolar agenesis cases from a material of 2847 radiographs. On each radiograph, dental maturity of all available mandibular premolars, canines and 2nd molars was evaluated and categorized in maturity stages according to Haavikko whose material served as control material. Descriptive statistics given by sample mean, standard deviation and range for each tooth stratified by gender and agenesis. Ninety-five percentage confidence limits and T-statistics were used. p-values <5% were considered significant. In unilateral agenesis, the canines are specifically delayed in both girls and boys, with a larger delay in girls (p=0.009). The second molar is not delayed in boys (p=0.98) but is in girls (p=0.04). The differences in delay for the canine compared to the second molar are significant for both girls and boys. The results show a considerable delay in tooth maturation within the canine/premolar innervation field predominantly in girls. The 2nd molar is delayed in girls but not in boys. © 2010 John Wiley & Sons A/S.

Coronectomy of Deeply Impacted Lower Third Molar: Incidence of Outcomes and Complications after One Year Follow-Up

PubMed Central

Heijsters, Guido; Salem, Ahmed Sobhy; Van Slycke, Sarah; Schepers, Serge; Politis, Constantinus; Vrielinck, Luc

2015-01-01

ABSTRACT Objectives The purpose of present study was to assess the surgical management of impacted third molar with proximity to the inferior alveolar nerve and complications associated with coronectomy in a series of patients undergoing third molar surgery. Material and Methods The position of the mandibular canal in relation to the mandibular third molar region and mandibular foramen in the front part of the mandible (i.e., third molar in close proximity to the inferior alveolar nerve [IAN] or not) was identified on panoramic radiographs of patients scheduled for third molar extraction. Results Close proximity to the IAN was observed in 64 patients (35 females, 29 males) with an impacted mandibular third molar. Coronectomy was performed in these patients. The most common complication was tooth migration away from the mandibular canal (n = 14), followed by root exposure (n = 5). Re-operation to remove the root was performed in cases with periapical infection and root exposure. Conclusions The results indicate that coronectomy can be considered a reasonable and safe treatment alternative for patients who demonstrate elevated risk for injury to the inferior alveolar nerve with removal of the third molars. Coronectomy did not increase the incidence of damage to the inferior alveolar nerve and would be safer than complete extraction in situations in which the root of the mandibular third molar overlaps or is in close proximity to the mandibular canal. PMID:26229580

Two new genera and two new species of proteocephalidean tapeworms (Eucestoda) from reptiles and amphibians in Australia.

PubMed

de Chambrier, Sophie; de Chambrier, Alain

2010-11-01

The examination of the type series of Ophiotaenia Gallardi (Johnston, 1911) (syn. Proteocephalus gallardi Johnston, 1911) revealed that it is a mixture of two species of different genera. Lectotype of Ophiotaenia gallardi is designated and the species is redescribed on the basis of it, conspecific paralectotypes and additional materials. The remaining part of the type series belongs to Vandiermenia gen. n. (Acanthotaeniinae), with V Beveridgei sp. n. as the type- and only species. The new genus differs from all other acanthotaeniine genera, i.e. Rostellotaenia Freze, 1963, Acanthotaenia von Linstow, 1903 and Kapsulotaenia Freze, 1963, by the presence of cortical uterine stem and paramuscular vitelline follicles, particular structure of the internal longitudinal musculature (absent laterally and more developed than in the three above-mentioned genera) and testes limited in two fields separated medially. Type series of Ophiotaenia mjobergi (Nybelin, 1917) (syn. Crepidobothrium mjobergi Nybelin, 1917), O. amphiboluri (Nybelin, 1917) (syn. Crepidobothrium amphiboluri Nybelin, 1917), O. striata (Johnston, 1914) (syn. Acanthotaenia striata Johnston, 1914) and O. longmani Johnston, 1916 are revised and compared with Ophiotaenia gallardi. Australotaenia hylae (Johnston, 1912) comb. n. is proposed for Ophiotaenia hylae Johnston, 1912. Australotaenia gen. n. differs from the remaining genera of the subfamily Acanthotaeniinae by (1) the Type 2 of the formation of the uterus (sensu de Chambrier et al. 2004) (all the other acanthotaeniines have the Type 1 of uterine development), (2) the cortical position of the uterine stem (all the other genera have medullary uterine stem) and (3) the morphology of the internal longitudinal musculature, which is composed of few well-developed bundles of fibres (in contrast to the other genera). The new genus also differs from ãby eggs not in clusters, the presence of two testicular fields (versus one in Vandiermenia) and the structure of the longitudinal internal musculature with only 8-10 bundles (versus formed by numerous bundles and with the presence of secondary muscles in Vandiermenia). Ophiotaenia sp. sensu de Chambrier (2004), a parasite of Litoria moorei, is described as Australotaenia grobeli sp. n., which can be distinguished from Australotaenia hylae by the smaller number of testes (46-76 versus 74-106), greater cirrus-sac length/width of proglottis ratio (27-33% versus 17-19%) and the smaller ovary width/proglottis width ratio (55-63% versus 68-71%).

Correlation between Condylar Fracture Pattern after Parasymphyseal Impact and Condyle Morphological Features: A Retrospective Analysis of 107 Chinese Patients.

PubMed

Han, Lu; Long, Ting; Tang, Wei; Liu, Lei; Jing, Wei; Tian, Wei-Dong; Long, Jie

2017-02-20

The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fracture patterns and condylar morphological characteristics. We conducted a retrospective analysis of 107 patients admitted to the West China Hospital of Stomatology for bilateral condylar fractures caused by parasymphyseal impact. The patients were divided into five groups according to the type of condylar fracture. Ten parameters were evaluated on three-dimensional (3D) reconstruction mandible models through the Mimics 16.0 (Materialize Leuven, Belgium) anthropometry toolkit. Each parameter of the 3D models was analyzed using multivariate analysis. Multinomial logistic regression analyses were used to examine the relationships between the five groups. The results showed that the differences of condylar head width (M1), condylar neck width (M3), the ratio of condylar head width to condylar anteroposterior diameter (M1/M2), the ratio of condylar head width to condylar neck width (M1/M3), the ratio of condylar height to ramus height (M8/M7), and mandibular angle (M10) were statistically significant (p < 0.05). Type A condylar head fractures were positively associated with M1 (compared to Type B: OR =1.627, 95% CI: 1.123, 2.359; compared to Type C: OR = 1.705, 95% CI: 1.170, 2.484) and M1/M2 (compared to Type B: OR =1.034, 95% CI: 0.879, 2.484). Type B condylar head fractures were negatively associated with M10 (compared to Type C: OR = 0.909, 95% CI: 0.821, 1.007). Condylar neck fractures were negatively associated with M3 (compared to condylar head: OR = 0.382, CI: 0.203, 0.720 ; compared to condylar base: OR = 0.436, 95% CI: 0.218, 0.874), and positively associated with M1/M3 (compared to condylar head: OR = 1.229, 95% CI: 1.063, 1.420 compared to condylar base: OR = 1.223, 95% CI: 1.034, 1.447). Condylar base fractures were positively associated with M10 (OR = 1.095, 95% CI: 1.008, 1.189) and negatively associated with M8/M7 (OR = 0.855, 95% CI: 0.763, 0.959) as compared with condylar head fractures. Condylar fracture pattern is associated with the anatomical features of the condyles when a fracture occurs from parasymphyseal impact.

Correlation between Condylar Fracture Pattern after Parasymphyseal Impact and Condyle Morphological Features: A Retrospective Analysis of 107 Chinese Patients

PubMed Central

Han, Lu; Long, Ting; Tang, Wei; Liu, Lei; Jing, Wei; Tian, Wei-Dong; Long, Jie

2017-01-01

Background: The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fracture patterns and condylar morphological characteristics. Methods: We conducted a retrospective analysis of 107 patients admitted to the West China Hospital of Stomatology for bilateral condylar fractures caused by parasymphyseal impact. The patients were divided into five groups according to the type of condylar fracture. Ten parameters were evaluated on three-dimensional (3D) reconstruction mandible models through the Mimics 16.0 (Materialize Leuven, Belgium) anthropometry toolkit. Each parameter of the 3D models was analyzed using multivariate analysis. Multinomial logistic regression analyses were used to examine the relationships between the five groups. Results: The results showed that the differences of condylar head width (M1), condylar neck width (M3), the ratio of condylar head width to condylar anteroposterior diameter (M1/M2), the ratio of condylar head width to condylar neck width (M1/M3), the ratio of condylar height to ramus height (M8/M7), and mandibular angle (M10) were statistically significant (p < 0.05). Type A condylar head fractures were positively associated with M1 (compared to Type B: OR =1.627, 95% CI: 1.123, 2.359; compared to Type C: OR = 1.705, 95% CI: 1.170, 2.484) and M1/M2 (compared to Type B: OR =1.034, 95% CI: 0.879, 2.484). Type B condylar head fractures were negatively associated with M10 (compared to Type C: OR = 0.909, 95% CI: 0.821, 1.007). Condylar neck fractures were negatively associated with M3 (compared to condylar head: OR = 0.382, CI: 0.203, 0.720; compared to condylar base: OR = 0.436, 95% CI: 0.218, 0.874), and positively associated with M1/M3 (compared to condylar head: OR = 1.229, 95% CI: 1.063, 1.420 compared to condylar base: OR = 1.223, 95% CI: 1.034, 1.447). Condylar base fractures were positively associated with M10 (OR = 1.095, 95% CI: 1.008, 1.189) and negatively associated with M8/M7 (OR = 0.855, 95% CI: 0.763, 0.959) as compared with condylar head fractures. Conclusions: Condylar fracture pattern is associated with the anatomical features of the condyles when a fracture occurs from parasymphyseal impact. PMID:28218215

Preparation of autogenous bone grafts in two different bone mills.

PubMed

Erpenstein, H; Diedrich, P; Borchard, R

2001-12-01

The purpose of this study was to evaluate the performance of two bone mills (R Quetin Bone Mill and Micro Knochenmühle, Aesculap) for the grinding of autogenous bone (intraoral, cortical) according to the following criteria: (1) loss of bone during the grinding process, (2) particle size of the chips, (3) variability in chip size, (4) technical handling, and (5) cost-benefit ratio. The amount of material loss was determined by harvesting 30 bone cores from the mandibular symphysis of a pig. Each specimen was weighed before and after the grinding procedure on scales with an accuracy of 0.1 mg. The size and variability of the bone particles were determined histomorphometrically. Twenty-seven bone specimens from different patients were analyzed. Eight were ground with the Aesculap and 12 with the Quetin mill. Seven specimens harvested with a Brånemark implant bur served as controls. A histologic section was prepared from each specimen, and 10 bone particles per section were subjected to histomorphometric analysis. The Quetin mill was superior in all points to the Aesculap mill for the requirements of a periodontal practice.

Unerupted lower third molar extractions and their risks for mandibular fracture.

PubMed

Corrêa, Ana Paula Simões; Faverani, Leonardo Perez; Ramalho-Ferreira, Gabriel; Ferreira, Sabrina; Ávila Souza, Francisley; de Oliveira Puttini, Igor; Rangel Garcia-Júnior, Idelmo

2014-05-01

As every surgical procedure extraction of third molars can result in several complications, among them the mandibular angle fracture. Predisposing factors for fracture should be analyzed during and after the surgery. This paper aims to discuss the predisposing factors to the occurrence of mandibular angle fractures during and after the procedure for third molars extraction, as well as surgical principles to avoid this complication.

Tissue Engineered Bone Using Polycaprolactone Scaffolds Made by Selective Laser Sintering

DTIC Science & Technology

2005-01-01

temporo - mandibular joint (TMJ) pose many challenges for bone tissue engineering. Adverse reactions to alloplastic, non- biological materials result in...producing a prototype mandibular condyle scaffold based on an actual pig condyle. INTRODUCTION Repair and reconstruction of complex joints such as the...computed tomography (CT) data with a designed porous architecture to build a complex scaffold that mimics a mandibular condyle. Results show that