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Sample records for cuarto molar supernumerario

  1. Further analyses of Rio Cuarto impact glass

    NASA Technical Reports Server (NTRS)

    Schultz, Peter H.; Bunch, T. E.; Koeberl, C.; Collins, W.

    1993-01-01

    Initial analyses of the geologic setting, petrology, and geochemistry of glasses recovered from within and around the elongate Rio Cuarto (RC) craters in Argentina focused on selected samples in order to document the general similarity with impactites around other terrestrial impact craters and to establish their origin. Continued analysis has surveyed the diversity in compositions for a range of samples, examined further evidence for temperature and pressure history, and compared the results with experimentally fused loess from oblique hypervelocity impacts. These new results not only firmly establish their impact origin but provide new insight on the impact process.

  2. Deciduous molar hypomineralization and molar incisor hypomineralization.

    PubMed

    Elfrink, M E C; ten Cate, J M; Jaddoe, V W V; Hofman, A; Moll, H A; Veerkamp, J S J

    2012-06-01

    This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. This study focused on the relationship between Deciduous Molar Hypomineralization (DMH) and Molar Incisor Hypomineralization (MIH). First permanent molars develop during a period similar to that of second primary molars, with possible comparable risk factors for hypomineralization. Children with DMH have a greater risk of developing MIH. Clinical photographs of clean, moist teeth were taken with an intra-oral camera in 6,161 children (49.8% girls; mean age 74.3 mos, SD ± 5.8). First permanent molars and second primary molars were scored with respect to DMH or MIH. The prevalence of DMH and MIH was 9.0% and 8.7% at child level, and 4.0% and 5.4% at tooth level. The Odds Ratio for MIH based on DMH was 4.4 (95% CI, 3.1-6.4). The relationship between the occurrence of DMH and MIH suggests a shared cause and indicates that, clinically, DMH can be used as a predictor for MIH. PMID:22370445

  3. Ruptured tubal molar pregnancy.

    PubMed

    Yakasai, I A; Adamu, N; Galadanchi, H S

    2012-01-01

    Molar pregnancies in most instances develop within the uterine cavity, but may occur at any site. Ectopic molar pregnancy is a rare event. The objective of this study was to present a case of ruptured tubal molar gestation, discuss its clinical features and ways to improve diagnostic accuracy. A 35-year-old woman presented with features suggestive of ruptured tubal ectopic pregnancy. There was neither any evidence at the time of presentation to suspect a molar gestation, nor β human chorionic gonadotrophin (βhCG) hormone estimation was done, but only a clearview pregnancy test was carried out. She had total left salpingectomy and histological evaluation of the specimen revealed complete hydatidiform mole. The hCG level normalized within 3 weeks of follow-up. Clinical features of ectopic molar pregnancy may be indistinguishable from non-molar ectopic pregnancy. We recommend βhCG estimation as well as histological examination of the surgical specimen for all patients coming with features suggestive of ectopic pregnancy. PMID:23238205

  4. Endodontic treatment of molars

    PubMed Central

    Habl, Claudia; Bodenwinkler, Andrea; Stürzlinger, Heidi

    2006-01-01

    Objective Commissioned by the German Institute of Medical Documentation and Information (DIMDI) the Austrian Health Institute (ÖBIG) prepared a HTA report on the long-term effectiveness of endodontic treatment (root canal treatment, RCT) of molars. The focus is to examine factors influencing the outcome of endodontic treatment and showing their impact on long-term results. Additionally, economic aspects of root canal treatment in Germany are discussed. Methodology By performing a systematic literature search in 29 databases (e.g. MEDLINE), the Cochrane Library and by hand searching two peer-reviewed endodontic journals the authors could identify 750 relevant articles, of which finally 18 qualified for assessment. Results The findings show that the most relevant factor influencing the long-term outcome of endodontic treatment is the preoperative status of a tooth. The lowest success rates are reported for molars with a preoperative devital or necrotic pulp and persisting periapical lesions (so called periapical disease). Discussion Even if there is no positive selection of patients and the RCT is performed by a normal dentist rather than an endodontist - a fact which is very common - long-term success rates of more then 90% are possible. The overall success rates for endodontic treatment of molars therefore seem to be similar to those of other tooth-types. Conclusions Especially primary, conventional (i.e. non-surgical) root canal treatment is an effective and efficient therapy for endodontically ill molars, especially if no large periapical lesion persists. Nonetheless, a long term successful endodontic therapy requires a thorough assessment of the pre-operative status of the molar and treatment according to established guidelines. PMID:21289954

  5. The formation and evolution of Hule and Río Cuarto maars, Costa Rica

    NASA Astrophysics Data System (ADS)

    Alvarado, Guillermo E.; Soto, Gerardo J.; Salani, Flavia M.; Ruiz, Pablo; de Mendoza, Luis Hurtado

    2011-04-01

    The Hule and Río Cuarto maars are respectively located 11 and 18 km northward of the active crater of Poás volcano, on the Caribbean side of the Central Volcanic Range of Costa Rica. They lie on the northern part of Poás volcano massif, along a N-S trending, ~ 27 km-long volcanic fracture crossing the Poás volcano. The volcanic products from Hule maar (2.3 km × 1.8 km, area ~ 3.5 km 2) are mainly pyroclastic surges (poorly vesiculated andesites with very small plagioclases), silica-rich andesitic pumice flows, air-fall deposits, ballistic blocks, and reworked deposits that overlie the regional Pleistocene volcanic basement. They were produced during three main explosive phases. Two overlapping pyroclastic cones have developed within the Hule maar, and at least three lava fields are related to them (high-Al basalt to basaltic andesite). Another maar, Pata de Gallo (400 m across), is located less than 1 km off the SE rim of Hule. Río Cuarto is a nearly circular maar (700-850 m across) with a surface area of 0.33 km 2. Río Cuarto products include surges, ballistics and air-fall tephra, produced during three main explosive phases. These deposits show a narrow fan oriented westward, according to westerly wind direction. They indicate a westerly-directed surge (first 2 km), followed by air-fall deposits (up to 5 km away). Radiocarbon dating has shown that Hule was formed ~ 6.2 ka ago and Pata de Gallo probably formed ~ 2.8 ka ago, while the intra-maar products could have ages of ~ 1.7 ka or ~ 0.7 ka, indicating that Hule is a polygenetic maar. There are no radiocarbon ages yet for dating the formation of Río Cuarto maar, but archaeological data suggest that it erupted between 3-4 ka ago. The volume of pyroclastic deposits associated to Hule maar is estimated to be 0.51-0.53 km 3, from which ~ 20% is juvenile material, therefore 0.07-0.08 km 3 of new dense rock equivalent (DRE) magma, after subtracting 20-30% of porosity. The tephra from Río Cuarto is estimated

  6. Molar Incisor Hypomineralization.

    PubMed

    Rao, Murali H; Aluru, Srikanth C; Jayam, Cheranjeevi; Bandlapalli, Anila; Patel, Nikunj

    2016-01-01

    Molar incisor hypomineralization (MIH) is a developmental defect affecting teeth. High prevalence rates of MIH and its clinical implications are significant for both the patients and clinicians. A wide variation in defect prevalence (2.4-40.2%) is reported. It seems to differ with regions and various birth cohorts. Some of the recent prevalence studies are tabulated. Patient implications include hypersensitive teeth, rapid progression of caries, mastication impairment due to rapid attrition, and esthetic repercussions. Implications for clinicians include complexity in treatment planning and treatment implementation, poor prognosis of the restorations, difficulty in achieving pain control during treatment, and behavior management problems. Intention of this paper is to review the etio-pathogenesis, prevalence, clinical features, diagnostic features, and eventually present a sequential treatment approach, i.e., in accordance with current clinical practice guidelines. PMID:27595731

  7. Grazing Impacts Upon Earth's Surface: Towards an Understanding of the Rio Cuarto Crater Field

    NASA Astrophysics Data System (ADS)

    Beech, Martin

    2014-10-01

    The origin of the Rio Cuarto crater field, Argentina has been widely debated since the early 1990s when it was first brought to public attention. In a binary on-off sense, however, the craters are either of a terrestrial origin or they formed via a large asteroid impact. While there are distinct arguments in favour of the former option being the correct interpretation, it is the latter possibility that is principally investigated here, and five distinct impact formation models are described. Of the impact scenarios it is found that the most workable model, although based upon a set of fine-tuned initial conditions, is that in which a large, 100-150-m initial diameter asteroid, entered Earth's atmosphere on a shallow angle path that resulted in temporary capture. In this specific situation a multiple-thousand kilometer long flight path enables the asteroid to survive atmospheric passage, without suffering significant fragmentation, and to impact the ground as a largely coherent mass. Although the odds against such an impact occurring are extremely small, the crater field may nonetheless be interpreted as having potentially formed via a very low-angle, smaller than 5° to the horizon, impact with a ground contact speed of order 5 km/s. Under this scenario, as originally suggested by Schultz and Lianza (Nature 355:234, 1992), the largest of the craters (crater A) in the Rio Cuarto structure was produced in the initial ground impact, and the additional, smaller craters are interpreted as being formed through the down-range transport of decapitated impactor material and crater A ejecta.

  8. Controversy of the third molars.

    PubMed

    Pitekova, L; Satko, I

    2009-01-01

    Third molars are teeth that have little functional value and a relatively high rate of associated pain and disease. Their value as a part of the dentition of modern people is dubious. Our aim is to review the evolution, morbidity and complications of the third molars (Ref. 19). Full Text (Free, PDF) www.bmj.sk. PMID:19408843

  9. [Headgear-free molar distalization].

    PubMed

    Manhartsberger, C

    1994-12-01

    The difficulty in treating dentoalveolar class II disharmonies is briefly outlined. An innovative treatment method is presented which makes possible a distalization without the use of headgear. In the treatment method bands are cemented on the first molars, next impressions are made of the upper and lower dental arch, and then the impressions are poured with plaster. Following this the models are mounted in centric relationship in an articulator and the bite is opened 2 mm to 3 mm, so that the molars can be moved without making occlusal contact. The apparatus, an acrylic splint, is constructed in such a fashion as to cover the palatal surfaces from 2nd premolar to 2nd premolar. In addition, the premolars are also covered occlusally and buccally and the canine tips and the incisal edges are covered labially. A headgear tube is attached at the buccal surface in the premolar region of the acrylic splint. This acrylic splint, which is itself retentive, is cemented using glass ionomer cement. Combining this apparatus with a modified Nance Button makes it possible to establish an anchoring segment which is able to retain its position in the face of molar distalization. Molar distalization is then performed using a 0.032 inch stainless steel wire, which is placed between the headgear tube of the acrylic splint and the headgear tube of the band of the first molar. Highly elastic nickel-titanium open coil springs are used as the force elements. PMID:7851830

  10. Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization.

    PubMed

    Negre-Barber, A; Montiel-Company, J M; Boronat-Catalá, M; Catalá-Pizarro, M; Almerich-Silla, J M

    2016-01-01

    Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Kappa 0.83) performed the intraoral examinations at the University of Valencia between November 2013 and 2014, applying the diagnostic criteria for MIH and HSPM adopted by the European Academy of Paediatric Dentistry. 100 children (24.2%) presented MIH and 60 (14.5%) presented HSPM. Co-occurrence of the two defects was observed in 11.1% of the children examined. The positive predictive value was 76.7% (63.9-86.6) and the negative predictive value 84.7% (80.6-88.3). The positive likelihood ratio (S/1-E) was 10.3 (5.9-17.9) and the negative likelihood ratio (1-S/E) 0.57 (0.47-0.68). The odds ratio was 18.2 (9.39-35.48). It was concluded that while the presence of HSPM can be considered a predictor of MIH, indicating the need for monitoring and control, the absence of this defect in primary dentition does not rule out the appearance of MIH. PMID:27558479

  11. Complications after third molar surgery.

    PubMed

    Pitekova, L; Satko, I; Novotnakova, D

    2010-01-01

    The authors describe the incidence of postoperative complications after the surgical removal of third molars, most common postoperative complications and their symptoms as well as risk factors leading to greater incidence of postoperative complications (Ref. 17). Full Text (Free, PDF) www.bmj.sk. PMID:20568422

  12. Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization

    PubMed Central

    Negre-Barber, A.; Montiel-Company, J. M.; Boronat-Catalá, M.; Catalá-Pizarro, M.; Almerich-Silla, J. M.

    2016-01-01

    Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Kappa 0.83) performed the intraoral examinations at the University of Valencia between November 2013 and 2014, applying the diagnostic criteria for MIH and HSPM adopted by the European Academy of Paediatric Dentistry. 100 children (24.2%) presented MIH and 60 (14.5%) presented HSPM. Co-occurrence of the two defects was observed in 11.1% of the children examined. The positive predictive value was 76.7% (63.9–86.6) and the negative predictive value 84.7% (80.6–88.3). The positive likelihood ratio (S/1-E) was 10.3 (5.9–17.9) and the negative likelihood ratio (1-S/E) 0.57 (0.47–0.68). The odds ratio was 18.2 (9.39–35.48). It was concluded that while the presence of HSPM can be considered a predictor of MIH, indicating the need for monitoring and control, the absence of this defect in primary dentition does not rule out the appearance of MIH. PMID:27558479

  13. Fracture behavior of human molars.

    PubMed

    Keown, Amanda J; Lee, James J-W; Bush, Mark B

    2012-12-01

    Despite the durability of human teeth, which are able to withstand repeated loading while maintaining form and function, they are still susceptible to fracture. We focus here on longitudinal fracture in molar teeth-channel-like cracks that run along the enamel sidewall of the tooth between the gum line (cemento-enamel junction-CEJ) and the occlusal surface. Such fractures can often be painful and necessitate costly restorative work. The following study describes fracture experiments made on molar teeth of humans in which the molars are placed under axial compressive load using a hard indenting plate in order to induce longitudinal cracks in the enamel. Observed damage modes include fractures originating in the occlusal region ('radial-median cracks') and fractures emanating from the margin of the enamel in the region of the CEJ ('margin cracks'), as well as 'spalling' of enamel (the linking of longitudinal cracks). The loading conditions that govern fracture behavior in enamel are reported and observations made of the evolution of fracture as the load is increased. Relatively low loads were required to induce observable crack initiation-approximately 100 N for radial-median cracks and 200 N for margin cracks-both of which are less than the reported maximum biting force on a single molar tooth of several hundred Newtons. Unstable crack growth was observed to take place soon after and occurred at loads lower than those calculated by the current fracture models. Multiple cracks were observed on a single cusp, their interactions influencing crack growth behavior. The majority of the teeth tested in this study were noted to exhibit margin cracks prior to compression testing, which were apparently formed during the functional lifetime of the tooth. Such teeth were still able to withstand additional loading prior to catastrophic fracture, highlighting the remarkable damage containment capabilities of the natural tooth structure. PMID:22956116

  14. Mandibular lip bumper for molar torque control.

    PubMed

    Celentano, Giuseppe; Longobardi, Annalisa; Cannavale, Rosangela; Perillo, Letizia

    2011-01-01

    Treatment effects of lip bumpers alone include flaring of the mandibular incisors, distalization and uprighting of the mandibular first molars, and buccal expansion of the canines, premolars, and molar. Lip forces are transmitted through this appliance onto the molars. Moreover the lip bumper is able to derotate, expand or constrict, upright and reinforce the anchorage whereas torque control is lacking. Aim of this paper is the presentation of a new type of lip bumper that allows the molar torque control. PMID:21515237

  15. [Distalization of the upper second molar: biomechanics].

    PubMed

    Castaldo, A

    1991-01-01

    The Author shows a system to dystalize the second upper molars and, if necessary, the third upper molars. This system, easy to be adapted, is made up by a palatal bar inserted between the first upper molars, by a sectional and a 100 grams precalibrated open Sentalloy coil spring used as an active force. PMID:1784296

  16. Molar versus as a paradigm clash.

    PubMed Central

    Baum, W M

    2001-01-01

    The molar view of behavior arose in response to the demonstrated inadequacy of explanations based on contiguity. Although Dinsmoor's (2001) modifications to two-factor theory render it irrefutable, a more basic criticism arises when we see that the molar and molecular views differ paradigmatically. The molar view has proven more productive. PMID:11453623

  17. Geosphere-Biosphere Interactions in Bio-Activity Volcanic Lakes: Evidences from Hule and Rìo Cuarto (Costa Rica)

    PubMed Central

    Cabassi, Jacopo; Tassi, Franco; Mapelli, Francesca; Borin, Sara; Calabrese, Sergio; Rouwet, Dmitri; Chiodini, Giovanni; Marasco, Ramona; Chouaia, Bessem; Avino, Rosario; Vaselli, Orlando; Pecoraino, Giovannella; Capecchiacci, Francesco; Bicocchi, Gabriele; Caliro, Stefano; Ramirez, Carlos; Mora-Amador, Raul

    2014-01-01

    Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2)-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France) from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun (Cameroon). PMID

  18. Geosphere-biosphere interactions in bio-activity volcanic lakes: evidences from Hule and Rìo Cuarto (Costa Rica).

    PubMed

    Cabassi, Jacopo; Tassi, Franco; Mapelli, Francesca; Borin, Sara; Calabrese, Sergio; Rouwet, Dmitri; Chiodini, Giovanni; Marasco, Ramona; Chouaia, Bessem; Avino, Rosario; Vaselli, Orlando; Pecoraino, Giovannella; Capecchiacci, Francesco; Bicocchi, Gabriele; Caliro, Stefano; Ramirez, Carlos; Mora-Amador, Raul

    2014-01-01

    Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2)-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France) from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun (Cameroon). PMID

  19. Maxillary First Molar with Two Root Canals

    PubMed Central

    Rahimi, Saeed; Ghasemi, Negin

    2013-01-01

    Knowledge regarding the anatomic morphology of maxillary molars is absolutely essential for the success of endodontic treatment. The morphology of the permanent maxillary first molar has been reviewed extensively; however, the presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. This case report presents a patient with a maxillary first molar with two roots and two root canals, who was referred to the Department of Endodontics, Tabriz University of Medical Sciences, Iran. PMID:23862051

  20. Molar volumes and densities of minerals

    USGS Publications Warehouse

    Robie, Richard A.; Bethke, Philip M.

    1962-01-01

    These tables present critically chosen "best values" for the density and molar volume of selected mineral compounds. No attempt was made to be all-inclusive; rather we have tried to present data for chemically and physically well-defined phases for which the molar volume and/or density was knovvn to the order of 0. 2 percent.

  1. General technique of third molar removal.

    PubMed

    Farish, Sam E; Bouloux, Gary F

    2007-02-01

    The most commonly performed surgical procedure in most oral and maxillofacial surgery practices is the removal of impacted third molars. Extensive training, skill, and experience allow this procedure to be performed in an atraumatic fashion with local anesthesia, sedation, or general anesthesia. The decision to remove symptomatic third molars is not usually difficult, but the decision to remove asymptomatic third molars is sometimes less clear and requires clinical experience. A wide body of literature (discussed elsewhere in this issue) attempts to establish clinical practice guidelines for dealing with impacted teeth. Data is beginning to accumulate from third molar studies, which hopefully will provide surgeons and their patients with evidence-based guidelines regarding elective third molar surgery. PMID:18088862

  2. Expressly fabricated molar tube bases: enhanced adhesion.

    PubMed

    Sharma, Tarun; Phull, Tarun Singh; Rana, Tarun; Kumar, Varun

    2014-06-01

    Clinicians, Orthodontists and their patients' parents often expect the best results in the shortest time span possible. Orthodontic bonding of molar tubes has been an acceptable risk in a modern era of refined biomaterials and instrumentation. Although many orthodontists still prefer banding to bonding, it is the failure rate of the tubes on molars which accounts to an impedance in molar bonding. One of the reasons for molar attachment failures is attributed to improper adaptation of the buccal tube base with or without increased thickness of composite. Merits of banding the second molars especially when these are the terminal teeth for anchorage have been overemphasized in the literature. The present article presents a simple and relatively less time consuming technique of preparing molar tubes to be bonded on tooth surfaces which may be quite difficult to isolate especially for bonding, for example, mandibular second molars. The increased surface area of the composite scaffold helps not only in enhanced bond strength but also serves to reduce the incidence of plaque accumulation given the dexterity of invitro preparation. The removal of the occlusal part of the molar tube scaffold helps in prevention of open / raised bite tendencies. The present innovation, therefore, is not merely serendipity but a structured technique to overcome a common dilemma for the clinical orthodontist. The present dictum of banding being superior to molar tube bonding may prove to be futile with trendsetting molar attachments. It is also an established fact that bonding proves to be a lesser expensive modality when compared to banding procedures. PMID:25121070

  3. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases.

    PubMed

    Souki, Bernardo Q; Cheib, Paula L; de Brito, Gabriela M; Pinto, Larissa S M C

    2015-01-01

    Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction. PMID:26321848

  4. Unilateral Molar Distalization: A Nonextraction Therapy

    PubMed Central

    Prasad, M. Bhanu; Sreevalli, S.

    2012-01-01

    In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding. PMID:23320203

  5. Role of third molars in orthodontics.

    PubMed

    Almpani, Konstantinia; Kolokitha, Olga-Elpis

    2015-02-16

    The role of third molars in the oral cavity has been extensively studied over the years. Literature includes numerous diagnostic and treatment alternatives regarding the third molars. However, an issue that has not been discussed at the same level is their involvement in orthodontic therapy. The aim of this study is to present a review of the contemporary literature regarding the most broadly discussed aspects of the multifactorial role of third molars in orthodontics and which are of general dental interest too. PMID:25685759

  6. Molars and incisors: show your microarray IDs

    PubMed Central

    2013-01-01

    Background One of the key questions in developmental biology is how, from a relatively small number of conserved signaling pathways, is it possible to generate organs displaying a wide range of shapes, tissue organization, and function. The dentition and its distinct specific tooth types represent a valuable system to address the issues of differential molecular signatures. To identify such signatures, we performed a comparative transcriptomic analysis of developing murine lower incisors, mandibular molars and maxillary molars at the developmental cap stage (E14.5). Results 231 genes were identified as being differentially expressed between mandibular incisors and molars, with a fold change higher than 2 and a false discovery rate lower than 0.1, whereas only 96 genes were discovered as being differentially expressed between mandibular and maxillary molars. Numerous genes belonging to specific signaling pathways (the Hedgehog, Notch, Wnt, FGF, TGFβ/BMP, and retinoic acid pathways), and/or to the homeobox gene superfamily, were also uncovered when a less stringent fold change threshold was used. Differential expressions for 10 out of 12 (mandibular incisors versus molars) and 9 out of 10 selected genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of incisor versus molar differentially expressed genes revealed that 143 genes belonged to 9 networks with intermolecular connections. Networks with the highest significance scores were centered on the TNF/NFκB complex and the ERK1/2 kinases. Two networks ERK1/2 kinases and tretinoin were involved in differential molar morphogenesis. Conclusion These data allowed us to build several regulatory networks that may distinguish incisor versus molar identity, and may be useful for further investigations of these tooth-specific ontogenetic programs. These programs may be dysregulated in

  7. Single-rooted primary first mandibular molar

    PubMed Central

    Haridoss, SelvaKumar; Swaminathan, Kavitha; Rajendran, Vijayakumar; Rajendran, Bharathan

    2014-01-01

    Morphological variations like single-rooted molar in primary dentition are scarce. Understanding the root canal anatomy and variations is necessary for successful root canal therapy. The purpose of the present article is to report successful endodontic treatment of primary left mandibular first molar with an abnormal morphology of a single root. This case report highlights the importance of knowledge and its applications in the management of anomalous anatomic variants which play a crucial role in the success of endodontic treatment. PMID:25150245

  8. Maxillary molar distalization with first class appliance

    PubMed Central

    Ramesh, Namitha; Palukunnu, Biswas; Ravindran, Nidhi; Nair, Preeti P

    2014-01-01

    Non-extraction treatment has gained popularity for corrections of mild-to-moderate class II malocclusion over the past few decades. The distalization of maxillary molars is of significant value for treatment of cases with minimal arch discrepancy and mild class II molar relation associated with a normal mandibular arch and acceptable profile. This paper describes our experience with a 16-year-old female patient who reported with irregularly placed upper front teeth and unpleasant smile. The patient was diagnosed to have angles class II malocclusion with moderate maxillary anterior crowding, deep bite of 4 mm on a skeletal class II base with an orthognathic maxilla and retrognathic mandible and normal growth pattern. She presented an ideal profile and so molar distalization was planned with the first-class appliance. Molars were distalised by 8 mm on the right and left quadrants and class I molar relation achieved within 4 months. The space gained was utilised effectively to align the arch and establish a class I molar and canine relation. PMID:24577171

  9. Efficiency of a pendulum appliance for molar distalization related to second and third molar eruption stage.

    PubMed

    Kinzinger, Gero S M; Fritz, Ulrike B; Sander, Franz-Günter; Diedrich, Peter R

    2004-01-01

    A modified pendulum appliance, including a distal screw and special preactivated pendulum springs (built-in straightening activation and toe-in bending), was used for bilateral maxillary molar distalization in 36 adolescent patients in various stages of the molar dentition. The patients were divided into 3 groups (PG 1-3) according to the stage of eruption of their second and third molars. In PG 1 (18 patients), eruption of the second molars had either not yet taken place or was not complete. In PG 2 (15 patients), the second molars had already developed as far as the occlusal plane, with the third molars at the budding stage. In PG 3 (3 patients), germectomy of the wisdom teeth had been carried out, and the first and second molars on both sides had completely erupted. Analysis of cephalograms to identify any changes in the sagittal plane showed that, in the direction of distalization, a tooth bud acts on the mesial neighboring tooth like a fulcrum, and that tipping of the first molars in patients in whom the second molar was still at the budding stage was thus greater. In patients whose second molars had erupted completely, the degree of tipping was greater again when a third molar bud was located in the direction of movement. After previously completed germectomy of the wisdom teeth, almost exclusively bodily distalization of both molars is possible, even without bands being applied to the second molars. However, if the first and second molars are distalized simultaneously with a pendulum appliance, the duration of therapy will be longer, greater forces will have to be applied, and more anchorage will be lost. Statistical analysis of the results of dental-angular measurements showed significant differences in the degree of molar tipping and reciprocal incisor protrusion. The degree of distal tipping of first molars was less in patients with erupted second molars (PG 2 and PG 3) than in those whose second molars were not yet erupted (PG 1). For instance, the

  10. Orthodontic extrusion of horizontally impacted mandibular molars

    PubMed Central

    Ma, Zhigui; Yang, Chi; Zhang, Shanyong; Xie, Qianyang; Shen, Yuqing; Shen, Pei

    2014-01-01

    Objective: To introduce and evaluate a novel approach in treating horizontally impacted mandibular second and third molars. Materials and methods: An orthodontic technique was applied for treatment of horizontally impacted mandibular second and third molars, which included a push-type spring for rotation first, and then a cantilever for extrusion. There were 8 mandibular third molars (M3s) and 2 second molars (M2s) in this study. Tooth mobility, extraction time, the inclination and parallelism of the impacted tooth, alveolar bone height of the adjacent tooth, and the relationship of impacted M3 and the inferior alveolar nerve (IAN) were evaluated. Results: Two horizontally impacted M2s could be upright in the arch and good occlusal relationships were obtained after treatment. All impacted M3s were successfully separated from the IAN, without any neurologic consequences. The average extraction time was 5 minutes. There was a significant change in the inclination and parallelism of the impacted tooth after treatment. A new bone apposition with the average height of 3.2 mm was noted distal to the adjacent tooth. Conclusions: This two-step orthodontic technique as presented here may be a safe and feasible alternative in management of severely horizontally impacted mandibular molars, which achieves a successful separation of M3s from the IAN and an excellent position for M2s. PMID:25419364

  11. Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

    ERIC Educational Resources Information Center

    Bedenbaugh, John H.; And Others

    1988-01-01

    Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

  12. Lower third molar eruption following orthodontic treatment.

    PubMed

    Salehi, P; Danaie, S Momene

    2008-01-01

    This study assessed the effect of extraction and preservation of the 1st premolar on lower 3rd molar eruption. Orthodontic clinic records from 1993 to 1995 were evaluated before and after treatment and 8-9 years after treatment for 3 groups of patients: 32 with extraction of 1st premolars in both jaws, 32 with no extraction but orthodontic treatment and 48 controls with no extraction but orthodontic treatment in the upper jaws only. Successful eruption of 3rd molars was evaluated. There was a significant difference in the rates of successful eruptions in the extraction (42%), non-extraction (12%) and control (20%) groups. The findings indicate that 1st premolar extraction may increase the chance of 3rd molar eruption, leading to a lower incidence of health and economic complications. PMID:19161121

  13. Molar and molecular views of choice.

    PubMed

    Baum, William M

    2004-06-30

    The molar and molecular views of behavior are not different theories or levels of analysis; they are different paradigms. The molecular paradigm views behavior as composed of discrete units (responses) occurring at moments in time and strung together in chains to make up complex performances. The discrete pieces are held together as a result of association by contiguity. The molecular view has a long history both in early thought about reflexes and in associationism, and, although it was helpful to getting a science of behavior started, it has outlived its usefulness. The molar view stems from a conviction that behavior is continuous, as argued by John Dewey, Gestalt psychologists, Karl Lashley, and others. The molar paradigm views behavior as inherently extended in time and composed of activities that have integrated parts. In the molar paradigm, activities vary in their scale of organization--i.e., as to whether they are local or extended--and behavior may be controlled sometimes by short-term relations and sometimes by long-term relations. Applied to choice, the molar paradigm rests on two simple principles: (a) all behavior constitutes choice; and (b) all activities take time. Equivalence between choice and behavior occurs because every situation contains more than one alternative activity. The principle that behavior takes time refers not simply to any notion of response duration, but to the necessity that identifying one action or another requires a sample extended in time. The molecular paradigm's momentary responses are inferred from extended samples in retrospect. In this sense, momentary responses constitute abstractions, whereas extended activities constitute concrete particulars. Explanations conceived within the molecular paradigm invariably involve hypothetical constructs, because they require causes to be contiguous with responses. Explanations conceived within the molar paradigm retain direct contact with observable variables. PMID:15157981

  14. 40 CFR Table 1 to Subpart Ja of... - Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Molar Exhaust Volumes and Molar Heat... Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents Constituent MEVa dscf/mol MHCb Btu/mol... Inerts 0.85 0 a MEV = molar exhaust volume, dry standard cubic feet per gram-mole (dscf/g-mol)...

  15. 40 CFR Table 1 to Subpart Ja of... - Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Molar Exhaust Volumes and Molar Heat... Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents Constituent MEVa dscf/mol MHCb Btu/mol... Inerts 0.85 0 a MEV = molar exhaust volume, dry standard cubic feet per gram-mole (dscf/g-mol)...

  16. Ectopic molar pregnancy: a case report

    PubMed Central

    Bousfiha, Najoua; Erarhay, Sanaa; Louba, Adnane; Saadi, Hanan; Bouchikhi, Chahrazad; Banani, Abdelaziz; Fatemi, Hind El; Sekkal, Med; Laamarti, Afaf

    2012-01-01

    The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 years old nulliparus women who presented a vaginal bleeding, lower abdominal pain and 6 weeks amenorrhea corresponding to the last menstrual period. At the clinical examination, the arterial pressure was 100/60 mmHG. The gynecological examination was difficult because of lower abdominal pain. Serum gonadotropin activity was 3454 ui/l. Pelvic ultrasound revealed an irregular echogenic mass in the left adnexa. Diagnostic laparoscopy revealed a left-sided unruptured ampullary ectopic pregnancy. A left laparoscopic salpingectomy was performed. The systematic histologic test identified an ectopic partial molar pregnancy, which was confirmed by DNA ploidy image analysis. The patient was followed with weekly quantitative B-hCG titers until three successive B-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post treatment surveillance. PMID:22655097

  17. Ectopic molar pregnancy: a case report.

    PubMed

    Bousfiha, Najoua; Erarhay, Sanaa; Louba, Adnane; Saadi, Hanan; Bouchikhi, Chahrazad; Banani, Abdelaziz; El Fatemi, Hind; Sekkal, Med; Laamarti, Afaf

    2012-01-01

    The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 years old nulliparus women who presented a vaginal bleeding, lower abdominal pain and 6 weeks amenorrhea corresponding to the last menstrual period. At the clinical examination, the arterial pressure was 100/60 mmHG. The gynecological examination was difficult because of lower abdominal pain. Serum gonadotropin activity was 3454 ui/l. Pelvic ultrasound revealed an irregular echogenic mass in the left adnexa. Diagnostic laparoscopy revealed a left-sided unruptured ampullary ectopic pregnancy. A left laparoscopic salpingectomy was performed. The systematic histologic test identified an ectopic partial molar pregnancy, which was confirmed by DNA ploidy image analysis. The patient was followed with weekly quantitative B-hCG titers until three successive B-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post treatment surveillance. PMID:22655097

  18. Mass versus molar doses, similarities and differences.

    PubMed

    Chmielewska, A; Lamparczyk, H

    2008-11-01

    Generally, they are two systems expressing the amounts of active substance in a given drug product, i.e. mass and molar dose. Currently, the dose system based on the mass is widely used in which doses are expressed in grams or milligrams. On the other hand, the molar dose system is in direct relation to the number of molecules. Hence, the objective of this work was to compare both systems in order to find their advantages and disadvantages. Active substances belonging to the groups of antibiotics, nootropic agents, beta-blockers, vitamins, GABA-analog, COX-2 inhibitors, calcium channel antagonists, benzodiazepine receptor agonists, lipid-modifying agents (fibrates), non-steroidal anti-inflammatory drugs (profens), estrogens, neuroleptics, analgesics and benzodiazepines were considered. Moreover, products containing two active substances were also taken into account. These are mixtures of hydrochlorothiazide with active substances influencing the renin-angiotensin system and combined oral contraceptives. For each active substance, belonging to the groups mentioned above molar doses were calculated from mass doses and molar mass. Hence, groups of drugs with a single active substance, drugs with similar pharmacological activities, pharmaceutical alternatives, and drugs with a single active ingredient manufactured in different doses were compared in order to find which dose system describes more adequately differences between and within the groups mentioned above. Comparisons were supported by a number of equations, which theoretically justify the data, and relationships derived from calculations. PMID:19069248

  19. Selective alveolar corticotomy to intrude overerupted molars.

    PubMed

    Oliveira, Dauro Douglas; de Oliveira, Bruno Franco; de Araújo Brito, Helio Henrique; de Souza, Margareth Maria Gomes; Medeiros, Paulo José

    2008-06-01

    Orthodontic intrusion of overerupted molars in adults is challenging for most clinicians. Efficient intrusion can be achieved by combining selective alveolar corticotomies with a modified full-coverage maxillary splint to reduce surgical risks, treatment time, and costs for both orthodontists and patients. PMID:18538256

  20. Till Surgery do us Part: Unexpected Bilateral Kissing Molars

    PubMed Central

    Anish, Narayanankutty; Vivek, Velayudhannair; Thomas, Sunila; Daniel, Vineet Alex; Thomas, Jincy; Ranimol, Prasanna

    2015-01-01

    The occurrence impacted teeth, single or multiple is very common. But, phenomenon of kissing molars is an extremely rare phenomenon. Mandibular third molars are the most common impacted teeth. Mandibular first or second molars does not share the same frequency of occurrence. But, there are rare cases in which the occlusal surfaces of impacted molars are united by the same follicular space and the roots point in the opposite direction, and are termed as kissing molars. Sometimes, these teeth will be associated with pathologies. This article reports a rare case of mandibular bilateral kissing molars. PMID:25918627

  1. Patients' anxieties with third molar surgery.

    PubMed

    Earl, P

    1994-10-01

    There has been little study of patients' anxieties about third molar surgery despite its widespread practice. 105 patients were invited to complete questionnaires preoperatively to assess anxieties about the procedure and to assess how well it was explained. They were also asked post operatively to assess differences from expectations, accuracy of the preoperative explanation and which aspect would worry them most should the procedure be repeated. Patients generally found their worries as expected or even better. Few found events worse with only pain (12%) and paraesthesia (13%) of note. Although 88% of patients assessed pain as better than or as expected, 43% would fear it most if the procedure was repeated. Pain is the single most feared factor despite evidence that it is usually no worse than originally feared. Reassurance and adequate pain control are the most important factors to patients in third molar surgery, and this reassurance should start at operation booking rather than on admission. PMID:7999736

  2. Removal of Deeply Impacted Mandibular Molars by Sagittal Split Osteotomy

    PubMed Central

    Isler, Sabri Cemil

    2016-01-01

    Mandibular third molars are the most common impacted teeth. Mandibular first and second molars do not share the same frequency of occurrence. In rare cases the occlusal surfaces of impacted molars are united by the same follicular space and the roots pointing in opposite direction; these are called kissing molars. In some cases, a supernumerary fourth molar can be seen as unerupted and, in this case, such a supernumerary, deeply impacted fourth molar is seen neighboring kissing molars. The extraction of deeply impacted wisdom molars from the mandible may necessitate excessive bone removal and it causes complications such as damage to the inferior alveolar nerve and iatrogenic fractures of the mandible. This case report describes the use of the sagittal split osteotomy technique to avoid extensive bone removal and protect the inferior alveolar nerve during surgical extruction of multiple impacted teeth. PMID:27429810

  3. Enzyme Molar Fractions: A Powerful Tool for Understanding Enzyme Kinetics.

    ERIC Educational Resources Information Center

    Serra, Juan L.; And Others

    1986-01-01

    Deduces the relationship between reduced velocity and molar fractions for productive enzyme complexes; obtains the mathematical expression of molar fractions for an enzyme with two specific binding sites per molecule; and proposes a useful plot to follow the dependence of enzyme molar fractions with the concentration of one of its ligands. (JN)

  4. Molar tubal ectopic pregnancy: Report of two cases.

    PubMed

    Mbarki, Chaouki; Jerbi, Emna; Hsayaoui, Najeh; Zouari, Fatma; Ben Brahim, Ehsen; Oueslati, Hedhili

    2015-06-01

    Ectopic molar pregnancy is a rare occurrence and consequently not often considered as a diagnostic possibility. We report two cases of molar hydatidiform tubal pregnancy. Diagnosis of ectopic pregnancy was confirmed on clinical biological and sonographic investigations. Diagnosis of molar pregnancy was done on histopathology. The clinical course was favorable for both patients. Although rare, molar changes can occur at any site of an ectopic pregnancy. Clinical diagnosis of a molar pregnancy is difficult but histopathology is the gold standard for diagnosis. PMID:25510265

  5. Periodontal changes following molar intrusion with miniscrews

    PubMed Central

    Bayani, Shahin; Heravi, Farzin; Radvar, Mehrdad; Anbiaee, Najmeh; Madani, Azam Sadat

    2015-01-01

    Background: With the introduction of skeletal anchorage system, recently it is possible to successfully intrude molar teeth. On the other hand, there have been concerns about periodontal changes associated with intrusion and there are few studies on this topic, especially for posterior teeth. Materials and Methods: Ten female patients were enrolled in this study. Maxillary molar intrusion was achieved by inserting two miniscrews and a 17 × 25 titanium molybdenum alloy spring. Crestal height changes were evaluated at three intervals including: Baseline (T0), end of active treatment (T1) and 6 months after retention (T2). Other variables including probing depth, gingival recession, attachment level and bleeding on probing were evaluated by clinical measurements in the three above mentioned intervals. One-sample Kolmogrov-Smirnov test ascertained the normality of the data. For all patients, the changes in tooth position and crestal height were evaluated using one-sample t-test. (P < 0.05) Results: Supra-erupted molars were successfully intruded a mean of 2.1 ± 0.9 mm during active treatment (T0-T1). A mean bone resorption of 0.9 ± 0.9 mm in mesial crest and 1 ± 0.8 mm in distal crest had occurred in total treatment (T0-T2). A mean of 0.6 ± 1.4 mm bone was deposited on mesial crest during the retention period (T1-T2) following tooth relapse. On average, 0.8 ± 0.4 mm attachment gain was obtained. Gingival margin coronalized a mean of 0.8 ± 0.6 mm throughout the entire treatment. Probing depth showed no significant change during treatment. Conclusion: Within the limitations of this study, these results suggest that not only periodontal status was not negatively affected by intrusion, but also there were signs of periodontal improvement including attachment gain and shortening of clinical crown height. PMID:26288629

  6. Angle Class II, subdivision, with agenesis of mandibular second molars and extrusion of maxillary second molars *

    PubMed Central

    Tavares, Rubens Rodrigues

    2015-01-01

    This clinical case reports the treatment of an Angle Class II malocclusion in a young woman with a balanced face affected by agenesis of second and third mandibular molars and subsequent extrusion of second maxillary molars. The atypical and peculiar occlusal anomaly led to individualized treatment proposed in order to normalize dental malpositions, with subsequent rehabilitation of edentulous areas by means of a multidisciplinary approach. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) in partial fulfillment of the requirements for obtaining the title of certified by the BBO. PMID:25992995

  7. Mechanics analysis of molar tooth splitting.

    PubMed

    Barani, Amir; Chai, Herzl; Lawn, Brian R; Bush, Mark B

    2015-03-01

    A model for the splitting of teeth from wedge loading of molar cusps from a round indenting object is presented. The model is developed in two parts: first, a simple 2D fracture mechanics configuration with the wedged tooth simulated by a compact tension specimen; second, a full 3D numerical analysis using extended finite element modeling (XFEM) with an embedded crack. The result is an explicit equation for splitting load in terms of indenter radius and key tooth dimensions. Fracture experiments on extracted human molars loaded axially with metal spheres are used to quantify the splitting forces and thence to validate the model. The XFEM calculations enable the complex crack propagation, initially in the enamel coat and subsequently in the interior dentin, to be followed incrementally with increasing load. The fracture evolution is shown to be stable prior to failure, so that dentin toughness, not strength, is the controlling material parameter. Critical conditions under which tooth splitting in biological and dental settings are likely to be met, however rare, are considered. PMID:25584989

  8. Clinical significance of computed tomography assessment for third molar surgery.

    PubMed

    Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

    2014-07-28

    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

  9. 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

  10. Positional changes of the third molar in orthodontically treated patients

    PubMed Central

    Mihai, AM; Lulache, IR; Grigore, R; Sanabil, AS; Boiangiu, S; Ionescu, E

    2013-01-01

    Objective and Rationale. Over the years, the effects of the third molars eruption on the dental arches have been studied extensively. Still, literature provides less data regarding the effects of the orthodontic treatment on the third molars position. The aim of our study was to assess the positional changes of the third molars relative to the occlusal plane and to the second molar long axis, changes occurred during orthodontic treatment performed with or without premolar extractions. Method. This study included 20 orthodontic treated patients: 10 of them with premolar extractions and 10 without premolar extractions. The pretreatment and post treatment panoramic radiographs were analyzed, and the angles between the third molar long axis and the occlusal plane and between the long axis of the third molar and the long axis of the second molar were measured. Results. Changes in third molar position, from pretreatment to post treatment, for the two groups of patients were evaluated by using the Student’s t-test. The results of the statistical analysis revealed an improvement in third molars position, the best results were seen in the lower third molars, in the group of patients treated with premolar extractions. PMID:23904878

  11. Autotransplantation of Mandibular Third Molar: A Case Report

    PubMed Central

    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. PMID:23346422

  12. Intrusion of overerupted molars by corticotomy and orthodontic skeletal anchorage.

    PubMed

    Moon, Cheol-Hyun; Wee, Jin-Uk; Lee, Hyun-Sun

    2007-11-01

    This article describes the orthodontic treatment of a 26-year-old female patient with overerupted left maxillary molar teeth. Her chief complaint was that the maxillary left first and the second molar intruded into the space required for the mandibular left first and the second molars, preventing prosthodontic treatment. The authors performed a corticotomy and used orthodontic skeletal anchorage with a miniplate and orthodontic miniscrews with a head modified to provide a specially designed hook. With this approach, they were able to achieve a sufficient amount of molar intrusion without discomfort, root resorption, or extrusion of the adjacent teeth. The first molar was intruded 3.0 mm and second molar was intruded 3.5 mm during 2 months of treatment. These results have been maintained for 11 months. PMID:18004918

  13. Molar mass distribution and solubility modeling of asphaltenes

    SciTech Connect

    Yarranton, H.W.; Masliyah, J.H.

    1996-12-01

    Attempts to model asphaltene solubility with Scatchard-Hildebrand theory were hampered by uncertainty in molar volume and solubility parameter distribution within the asphaltenes. By considering asphaltenes as a series of polyaromatic hydrocarbons with randomly distributed associated functional groups, molar volume and solubility parameter distributions are calculated from experimental measurements of molar mass and density. The molar mass distribution of Athabasca asphaltenes is determined from interfacial tension and vapor pressure osmometry measurements together with plasma desorption mass spectrometry determinations from the literature. Asphaltene densities are calculated indirectly from mixtures of known concentration of asphaltene in toluene. Asphaltene density, molar volume, and solubility parameter are correlated with molar mass. Solid-liquid equilibrium calculations based on solubility theory and the asphaltene property correlations successfully predict experimental data for both the precipitation point and the amount of precipitated asphaltenes in toluene-hexane solvent mixtures.

  14. Ab initio molar volumes and Gaussian radii.

    PubMed

    Parsons, Drew F; Ninham, Barry W

    2009-02-12

    Ab initio molar volumes are calculated and used to derive radii for ions and neutral molecules using a spatially diffuse model of the electron distribution with Gaussian spread. The Gaussian radii obtained can be used for computation of nonelectrostatic ion-ion dispersion forces that underlie Hofmeister specific ion effects. Equivalent hard-sphere radii are also derived, and these are in reasonable agreement with crystalline ionic radii. The Born electrostatic self-energy is derived for a Gaussian model of the electronic charge distribution. It is shown that the ionic volumes used in electrostatic calculations of strongly hydrated cosmotropic ions ought best to include the first hydration shell. Ionic volumes for weakly hydrated chaotropic metal cations should exclude electron overlap (in electrostatic calculations). Spherical radii are calculated as well as nonisotropic ellipsoidal radii for nonspherical ions, via their nonisotropic static polarizability tensors. PMID:19140766

  15. Molar extinction coefficients of some fatty acids

    NASA Astrophysics Data System (ADS)

    Sandhu, G. K.; Singh, Kulwant; Lark, B. S.; Gerward, L.

    2002-10-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH 2O 2), acetic acid (C 2H 4O 2), propionic acid (C 3H 6O 2), butyric acid (C 4H 8O 2), n-hexanoic acid (C 6H 12O 2), n-caprylic acid (C 8H 16O 2), lauric acid (C 12H 24O 2), myristic acid (C 14H 28O 2), palmitic acid (C 16H 32O 2), oleic acid (C 18H 34O 2) and stearic acid (C 18H 36O 2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement between experiment and theory.

  16. Autotransplantation of a Buccally Erupted Matured Mandibular Third Molar to Replace a Grossly Decayed Second Molar.

    PubMed

    Yadav, Sukhwant Singh; Bodh, Ranjeet; Kaushik, Aishvarya; Talwar, Sangeeta

    2016-02-01

    Autotransplantation can be a treatment option for tooth loss as an alternative to fixed or implant-supported prostheses. It has predictable results comparable to implants, with reported success rates often greater than 90%. In present case, buccally erupted matured third molar was autotransplanted in extraction socket of grossly carious mandibular second molar. The tooth was splinted for 1 week followed by root canal treatment. After 12 months follow up, tooth was in perfect state of function and aesthetic with healthy periapical and periodontal architecture. High success rate was found in immature tooth transplantation in previous case reports. This case report describes that even matured tooth can also be used as donor if atraumatic extraction is possible and endodontic treatment is well performed. PMID:27042593

  17. Autotransplantation of a Buccally Erupted Matured Mandibular Third Molar to Replace a Grossly Decayed Second Molar

    PubMed Central

    Bodh, Ranjeet; Kaushik, Aishvarya; Talwar, Sangeeta

    2016-01-01

    Autotransplantation can be a treatment option for tooth loss as an alternative to fixed or implant-supported prostheses. It has predictable results comparable to implants, with reported success rates often greater than 90%. In present case, buccally erupted matured third molar was autotransplanted in extraction socket of grossly carious mandibular second molar. The tooth was splinted for 1 week followed by root canal treatment. After 12 months follow up, tooth was in perfect state of function and aesthetic with healthy periapical and periodontal architecture. High success rate was found in immature tooth transplantation in previous case reports. This case report describes that even matured tooth can also be used as donor if atraumatic extraction is possible and endodontic treatment is well performed. PMID:27042593

  18. Anchorage reinforcement with a fixed functional appliance during protraction of the mandibular second molars into the first molar extraction sites.

    PubMed

    Chhibber, Aditya; Upadhyay, Madhur

    2015-07-01

    Protraction of posterior teeth into edentulous spaces is a challenge. This report describes the treatment of a 19-year-old woman with missing mandibular first molars owing to caries. A fixed functional appliance was used for anchorage reinforcement during mandibular second molar protraction. Eight millimeters of bilateral protraction was done with bodily mesial movement of the molars and no lingual tipping of the incisors. PMID:26124039

  19. [Distalization of the upper second molar: clinical case].

    PubMed

    Castaldo, A; Blasi, S; Vettese, P

    1991-01-01

    The Authors showed a clinical case in which has been put on a distalizing system together with a palatal bar between the first upper molars, a sectional placed between the first and the second molar and a 100 g precalibrated Sentalloy coil. PMID:1784297

  20. Immunodetection and subcellular localization of Mal de Río Cuarto virus P9-1 protein in infected plant and insect host cells.

    PubMed

    Guzmán, Fabiana A; Arneodo, Joel D; Pons, Amalia B Saavedra; Truol, Graciela A; Luque, Andrés V; Conci, Luis R

    2010-08-01

    Mal de Río Cuarto virus (MRCV), a member of the genus Fijivirus, family Reoviridae, has a genome consisting of 10 dsRNA segments. The segment 9 (S9) possesses two non-overlapping open reading frames (ORF-1 and ORF-2) encoding two putative proteins, MRCV P9-1 and MRCV P9-2, both of unknown function. The MRCV S9 ORF-1 was RT-PCR amplified, expressed in pET-15b vector, and the recombinant protein produced was used to raise an antiserum in rabbit. Western blot with the specific MRCV P9-1 antiserum detected a protein of about 39 kDa molecular weight present in crude protein extracts from infected plants and insects. However, no reaction was observed when this antiserum was tested against purified virus. In contrast, only virus particles were detected by a MRCV-coat antiserum used as a validation control. These results suggest that MRCV S9 ORF-1 encodes a non-structural protein of MRCV. Immunoelectron microscopy assays confirmed these results, and localized the MRCV P9-1 protein exclusively in electron-dense granular viroplasms within the cytoplasm of infected plants and insects cells. As viroplasms are believed to be the replication sites of reoviruses, the intracellular location of MRCV P9-1 protein suggests that it might be involved in the assembly process of MRCV particles. PMID:20419342

  1. In vivo subcellular localization of Mal de Rio Cuarto virus (MRCV) non-structural proteins in insect cells reveals their putative functions

    SciTech Connect

    Maroniche, Guillermo A.; Mongelli, Vanesa C.; Llauger, Gabriela; Alfonso, Victoria; Taboga, Oscar

    2012-09-01

    The in vivo subcellular localization of Mal de Rio Cuarto virus (MRCV, Fijivirus, Reoviridae) non-structural proteins fused to GFP was analyzed by confocal microscopy. P5-1 showed a cytoplasmic vesicular-like distribution that was lost upon deleting its PDZ binding TKF motif, suggesting that P5-1 interacts with cellular PDZ proteins. P5-2 located at the nucleus and its nuclear import was affected by the deletion of its basic C-termini. P7-1 and P7-2 also entered the nucleus and therefore, along with P5-2, could function as regulators of host gene expression. P6 located in the cytoplasm and in perinuclear cloud-like inclusions, was driven to P9-1 viroplasm-like structures and co-localized with P7-2, P10 and {alpha}-tubulin, suggesting its involvement in viroplasm formation and viral intracellular movement. Finally, P9-2 was N-glycosylated and located at the plasma membrane in association with filopodia-like protrusions containing actin, suggesting a possible role in virus cell-to-cell movement and spread.

  2. Mandibular third molar autotransplantation--literature review with clinical cases.

    PubMed

    Mendes, Rui Amaral; Rocha, Germano

    2004-12-01

    Autotransplantation of mandibular third molars in a precocious phase of development is indicated when a substitute for adjacent compromised or missing molars is needed, and when mesial movements of the posterior teeth, the resultant loss of space, and overeruption of opposing teeth and consequent changes in the occlusion must be avoided. Provided that the apices of the mandibular third molar are immature, the immediate replacement of a lost or compromised tooth usually ensures a good outcome. Transplantation of third molars helps to maintain alveolar bone and enables endosseous implantation without requiring bone regeneration. We present examples of transplantation of mandibular third molars and review the factors that affect the success or failure of this procedure, such as atraumatic extraction and adequate immobilization of the transplanted tooth and root development after transplantation. Sex or age seem to have no effect on the final outcome. PMID:15588551

  3. Nonsurgical Endodontic Management of a Molar-Incisor Malformation-affected Mandibular First Molar: A Case Report.

    PubMed

    Yue, Wonyoung; Kim, Euiseong

    2016-04-01

    A molar-incisor malformation (MIM) is a newly reported type of dental anomaly that involves a characteristic root malformation in permanent first molars and deciduous second molars and a crown defect in permanent central incisors. This case report describes a nonsurgical root canal treatment of a MIM-affected molar by aid of a reformatted axial view of the tooth cone-beam computed tomography (CBCT). A MIM-affected molar has calcified canal orifices and a few immature accessory furcal canals. Conventional root canal treatment with the aid of CBCT followed by resin restoration was performed on the tooth. The malformed roots of MIM teeth generally make it difficult to apply conventional endodontic treatment; however, it was possible to do with the aid of the reformatted axial view of the CBCT. PMID:26706790

  4. Replacement of a first molar and 3 second molars by the mesial inclination of 4 impacted third molars in an adult with a Class II Division 1 malocclusion.

    PubMed

    Tomonari, Hiroshi; Yagi, Takakazu; Kuninori, Takaharu; Ikemori, Takahiro; Miyawaki, Shouichi

    2015-06-01

    This case report presents the successful replacement of 1 first molar and 3 second molars by the mesial inclination of 4 impacted third molars. A woman, 23 years 6 months old, had a chief complaint of crowding of her anterior teeth and linguoclination of a second molar on the left side. The panoramic radiographic images showed that the maxillary and mandibular third molars on both sides were impacted. Root resorption on the distal surfaces of the maxillary second molars was suspected. The patient was given a diagnosis of Angle Class II Division 1 malocclusion with severe crowding of the anterior teeth and 4 impacted third molars. After we extracted the treated maxillary second premolars and the second molars on both sides, the treated mandibular second premolar and the second molar on the left side, and the root canal-filled mandibular first molar on the right side, the 4 impacted third molars were uprighted and formed part of the posterior functional occlusion. The total active treatment period was 39 months. The maxillary and mandibular third molars on both sides successfully replaced the first and second molars. The replacement of a damaged molar by an impacted third molar is a useful treatment option for using sound teeth. PMID:26038080

  5. Quantitative prediction and molar description of the environment

    PubMed Central

    Baum, William M.

    1989-01-01

    Molecular explanations of behavior, based on momentary events and variables that can be measured each time an event occurs, can be contrasted with molar explanations, based on aggregates of events and variables that can be measured only over substantial periods of time. Molecular analyses cannot suffice for quantitative accounts of behavior, because the historical variables that determine behavior are inevitably molar. When molecular explanations are attempted, they always depend on hypothetical constructs that stand as surrogates for molar environmental variables. These constructs allow no quantitative predictions when they are vague, and when they are made precise, they become superfluous, because they can be replaced with molar measures. In contrast to molecular accounts of phenomena like higher responding on ratio schedules than interval schedules and free-operant avoidance, molar accounts tend to be simple and straightforward. Molar theory incorporates the notion that behavior produces consequences that in turn affect the behavior, the notion that behavior and environment together constitute a feedback system. A feedback function specifies the dependence of consequences on behavior, thereby describing properties of the environment. Feedback functions can be derived for simple schedules, complex schedules, and natural resources. A complete theory of behavior requires describing the environment's feedback functions and the organism's functional relations. Molar thinking, both in the laboratory and in the field, can allow quantitative prediction, the mark of a mature science. PMID:22478030

  6. Modification of uprighting spring for derotation of second molars.

    PubMed

    Mallikarjun, Vankre; Rachala, Madhukar Reddy; Aileni, Kaladhar Reddy; Jaipal, Pyata Reddy

    2013-01-01

    One of the most efficient ways for the correction of rotated upper molars is derotation with a transpalatal arch, but this appliance is usually favourable when the need for correction is same on both sides of the dental arch. Derotation of unilateral upper second molar is a difficult task, especially when there is no accessible tooth/ any attachment is available distal to it for the application of couple forces. We have designed a modification of uprighting spring which is far more convenient than using the conventional method of TPA for derotation of unilateral upper second molar. PMID:24640073

  7. Molar heat capacity and entropy of calcium metal

    USGS Publications Warehouse

    Hemingway, B.S.; Robie, R.A.; Chase, M.W.

    1997-01-01

    The heat capacity of calcium has been measured at 85 mean temperatures between T ??? 8 K and T ??? 369 K using an adiabatically-shielded calorimeter in an intermittent heating mode. At T = 298.15 K, the recommended values for the molar heat capacity, molar entropy, and molar enthalpy increment referred to T = 0 are (25.77 ?? 0.08) J??K-1??mol-1, (42.90 ?? 0.11) J??K-1??mol-1, and (5811 ?? 12) J??mol-1, respectively. The uncertainties are twice the standard deviation of the mean. ?? 1997 Academic Press Limited.

  8. Lingual Guttering Technique for Removal of Impacted Mandibular Third Molars

    PubMed Central

    Kale, Tejraj P; Pandit, Vikram S; Patil, Shankargouda; Pawar, Vivek; Shetty, Nisha

    2014-01-01

    Background: To assess the clinical feasibility of lingual bone guttering technique for surgical extraction of mandibular third molars. Materials and Methods: 20 patients with thick lingual cortical plate were included in the study. Surgical extraction of mandibular third molars by lingual bone guttering technique was performed in all the subjects. These subjects were evaluated for integrity of lingual cortical plate and sensation of lingual nerve postoperatively. Results: All extractions done by lingual bone guttering technique were clinically feasible to perform and no complications were seen. Conclusion: Lingual bone guttering technique can be used safely in extraction of mandibular third molars with thick lingual cortical plate. PMID:25214725

  9. Caries Management Strategies for Primary Molars

    PubMed Central

    Santamaria, R.M.; Innes, N.P.T.; Machiulskiene, V.; Evans, D.J.P.; Splieth, C.H.

    2014-01-01

    Minimal invasive approaches to managing caries, such as partial caries removal techniques, are showing increasing evidence of improved outcomes over the conventional complete caries removal. There is also increasing interest in techniques where no caries is removed. We present the 1-yr results of clinical efficacy for 3 caries management options for occlusoproximal cavitated lesions in primary molars: conventional restorations (CR; complete caries removal and compomer restoration), Hall technique (HT; no caries removal, sealing in with stainless steel crowns), and nonrestorative caries treatment (NRCT; no caries removal, opening up the cavity, teaching brushing and fluoride application). In sum, 169 children (3-8 yr old; mean, 5.56 ± 1.45 yr) were enrolled in this secondary care–based, 3-arm, parallel-group, randomized clinical trial. Treatments were carried out by specialist pediatric dentists or postgraduate trainees. One lesion per child received CR, HT, or NRCT. Outcome measures were clinical failure rates, grouped as minor failure (restoration loss/need for replacement, reversible pulpitis, caries progression, etc.) and major failure (irreversible pulpitis, abscess, etc.). There were 148 children (87.6%) with a minimum follow-up of 11 mo (mean, 12.23 ± 0.98 mo). Twenty teeth were recorded as having at least 1 minor failure: NRCT, n = 8 (5%); CR, n = 11 (7%); HT, n = 1 (1%) (p = .002, 95% CI = 0.001 to 0.003). Only the comparison between NRCT and CR showed no significant difference (p = .79, 95% CI = 0.78 to 0.80). Nine (6%) experienced at least 1 major failure: NRCT, n = 4 (2%); CR, n = 5 (3%); HT, n = 0 (0%) (p = .002, 95% CI = 0.001 to 0.003). Individual comparison of NRCT and CR showed no statistically significant difference in major failures (p = .75, 95% CI = 0.73 to 0.76). Success and failure rates were not significantly affected by pediatric dentists’ level of experience (p = .13, 95% CI = 0.12 to 0.14). The HT was significantly more successful

  10. On the Etiology of Molar-Incisor Hypomineralization.

    PubMed

    Vieira, Alexandre R; Kup, Elaine

    2016-01-01

    Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Reports on the etiology of the condition and possible risk factors are inconclusive and the original suggestion that MIH is an idiopathic condition is often cited. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. In this report, we provide a rationale to explain the preferential affection of molars and incisors. We suggest that MIH is a genetic condition based on its prevalence, which varies depending on the geographic location, and the evidence that on occasion second primary molars, permanent canines, and premolars can show signs of hypomineralization of enamel when molars and incisors are affected. PMID:27111773

  11. Determining Molar Combining Ratios Using Radioisotopes--A Student Experiment

    ERIC Educational Resources Information Center

    Sears, Jerry A.

    1976-01-01

    Outlines an experimental procedure in which an iodine radioisotope is used to determine molar combining ratios of lead and silver with the iodine. Tables and graphs show the definitive results that should be attainable. (CP)

  12. A Multidisciplinary Approach for Managing Severely Malaligned Lower Molars.

    PubMed

    Keinan, David; Birnboim-Blaum, Galit; Webber, Mariel

    2016-01-01

    An impacted mandibular molar is a common clinical situation that may damage adjacent teeth and impair periodontal health. Improper treatment brings the risk of damaging adjacent vital tissues. The risk can be reduced by early diagnosis and extraction of the impacted tooth by an experienced clinician. However, in clinical cases of two impacted molars, it may be beneficial for the patient to save at least one molar. This can be achieved by orthodontic alignment of one of the molars, while extracting the other. The decision should be based upon prognosis and risks for each procedure and for both teeth. The case presented here demonstrates a recommended clinical decision-making process before treatment, followed by monitored multidisciplinary treatment with adaptations made as the treatment progresses. PMID:26939154

  13. Reanalysis of the Lukeino molar (KNM-LU 335).

    PubMed

    Ungar, P S; Walker, A; Coffing, K

    1994-06-01

    This paper details a reanalysis of KNM-LU 335, a hominoid mandibular first molar dated to about 6 Ma from the Lukeino Formation, Kenya. Researchers have argued that this molar closely resembles those of modern chimpanzees and may approximate the ancestral morphotype of humans and chimpanzees. The investigation presented here describes a morphometric study of the Lukeino molar and M1s of Homo sapiens, Pan troglodytes, and early australopithecines. Results indicate that KNM-LU 335 differs from both human and chimpanzee M1s in relative distances (measured in three dimensions) between crown fissure termini. Further, the Lukeino molar shares with early australopithecines a pronounced flaring of the buccal surface of the crown not seen for either modern sample. Results of this study do not exclude KNM-LU 335 as a potential ancestral morphotype for Pan and Homo but provide no evidence that this morphotype resembled modern chimpanzees. PMID:8085609

  14. Treatment of a Maxillary First Molar with Two Palatal Roots

    PubMed Central

    Asghari, Vahideh; Rahimi, Saeed; Ghasemi, Negin; Talebzadeh, Bita; Norlouoni, Ahmad

    2015-01-01

    Thorough knowledge of the morphology and internal anatomy of the root canal system is essential, because it determines the successful outcome of endodontic treatment. The main goal of endodontic treatment is to prevent apical periodontitis and/or to promote the healing of periapical lesion. Presence of two canals or roots on the palatal side of the first maxillary molar has rarely been reported. This case report presents a maxillary first molar with two separate palatal roots. PMID:26523146

  15. Cervicothoracic Subcutaneous Emphysema and Pneumomediastinum After Third Molar Extraction.

    PubMed

    Picard, Maxime; Pham Dang, Nathalie; Mondie, Jean Michel; Barthelemy, Isabelle

    2015-12-01

    Third molar extraction is one of the most common interventions in dental and maxillofacial surgery. Complications are frequent and well documented, with swelling, pain, bleeding, infection, and lingual or alveolar nerve injury being the most common. This report describes a case of subcutaneous extensive emphysema and pneumomediastinum that occurred 4 days after extraction of an impacted right mandibular third molar. The management and etiology of this case and those reported in the literature are discussed. PMID:26341684

  16. Fusion or gemination? An unusual mandibular second molar

    PubMed Central

    Camargo, Angela Jordão; Arita, Emiko Saito; Watanabe, Plauto Christopher Aranha

    2015-01-01

    Fusion and gemination is not an uncommon finding and affected most primary dentition and the permanent maxillary incisors. These changes can develop a series of complication. A 11-year-old male presented radiography finding: an unusual mandibular second molar. A well-documented case brings a challenge for radiologists classify between fusion and gemination. In conclusion, this alteration although common in other regions, there are no case in the literature involving “second and third” molar. PMID:26945485

  17. The orthodontic extraction of permanent molars: a literature review.

    PubMed

    Chua, Emilia S L; Felicita, A Sumathi

    2015-05-01

    The most common cause of dental crowding is the presence of an arch-length--tooth-size discrepancy. Conventional methods of gaining space in orthodontics involve the extraction of teeth, often premolars. However, there are a number of clinical situations in which the extraction of permanent molars might be considered. This paper highlights the indications, advantages, disadvantages and timing of the extraction of the first, second and third permanent molars in the treatment of a crowded malocclusion. PMID:26219149

  18. Fusion or gemination? An unusual mandibular second molar.

    PubMed

    Camargo, Angela Jordão; Arita, Emiko Saito; Watanabe, Plauto Christopher Aranha

    2016-01-01

    Fusion and gemination is not an uncommon finding and affected most primary dentition and the permanent maxillary incisors. These changes can develop a series of complication. A 11-year-old male presented radiography finding: an unusual mandibular second molar. A well-documented case brings a challenge for radiologists classify between fusion and gemination. In conclusion, this alteration although common in other regions, there are no case in the literature involving "second and third" molar. PMID:26945485

  19. Root canal morphology of South Asian Indian maxillary molar teeth

    PubMed Central

    Singh, Shishir; Pawar, Mansing

    2015-01-01

    Objective: The objective was to study the root canal morphology of South Asian Indian Maxillary molars using a tooth clearing technique. Materials and Methods: Hundred teeth each comprising of first, second, and third molars collected from different dental schools and clinics in India were subjected to standard dye penetration, decalcification and clearing procedure before being studied. Results: The first molar mesiobuccal roots exhibited 69% Type I, 24% Type II, 4% Type IV, 2% Type V, and 1% exhibited a Vertuccis Type VIII canal anatomy. In the group with three separate roots the second molar mesiobuccal roots in exhibited 80.6% Type I, 15.3% Type II, 2.7% Type IV, and 1.4% Type V canal anatomy while the third molars mesiobuccal roots exhibited 57.4% Type I, 32% Type II, 2.1% Type III, 8.5% Type IV, 1% had a Type V canal anatomy in the similar group. Conclusion: A varied root canal anatomy was seen in the mesiobuccal root canal of the maxillary molars. PMID:25713497

  20. Kissing molars extraction: Case series and review of the literature

    PubMed Central

    Arjona-Amo, Manuel; Torres-Carranza, Eusebio; Batista-Cruzado, Antonio; Serrera-Figallo, Maria-Angeles; Crespo-Torres, Santos; Belmonte-Caro, Rodolfo; Albisu-Andrade, Claudio; Gutiérrez-Pérez, José-Luis

    2016-01-01

    Kissing molars are a very rare form of inclusion defined as molars included in the same quadrant, with occlusal surfaces contacting each other within a single dental follicle. We present four cases of this pathology: a 35 year-old male, referred to the Oral and Maxillofacial Surgery Department of the Hospital Virgen del Rocio in Seville, and three females of 24, 26, and 31 years, all of which had kissing molars that were treated by tooth extraction. We have found only 10 cases published in the medical literature in which this type of inclusion is briefly described, none of which elaborate on the surgical technique employed. In these cases, the indication for surgery is established when there is a history of recurring infections or cystic lesions associated with dental inclusions. The extraction of kissing molars requires an exhaustive comprehension of the anatomy of the region involved, sufficiently developed surgical abilities, and an extensive planning process. Key words:Impacted molar, kissing molar, surgical extraction. PMID:26855716

  1. Finite Element Reconstruction of a Mandibular First Molar

    PubMed Central

    Ehsani, Sara; Mirhashemi, Fatemeh Sadat; Asgary, Saeed

    2013-01-01

    Introduction Mandibular first molar is the most important tooth with complicated morphology. In finite element (FE) studies, investigators usually prefer to model anterior teeth with a simple and single straight root; it makes the results deviate from the actual case. The most complicated and time-consuming step in FE studies is modeling of the desired tooth, thus this study was performed to establish a finite element method (FEM) of reconstructing a mandibular first molar with the greatest precision. Materials and Methods An extracted mandibular first molar was digitized, and then radiographed from different aspects to achieve its outer and inner morphology. The solid model of tooth and root canals were constructed according to this data as well as the anatomy of mandibular first molar described in the literature. Result A three-dimensional model of mandibular first molar was created, giving special consideration to shape and root canal system dimensions. Conclusion This model may constitute a basis for investigating the effect of different clinical situations on mandibular first molars in vitro, especially on its root canal system. The method described here seems feasible and reasonably precise foundation for investigations. PMID:23717327

  2. Standardised studies on Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM): a need.

    PubMed

    Elfrink, M E C; Ghanim, A; Manton, D J; Weerheijm, K L

    2015-06-01

    In November 2014, a review of literature concerning prevalence data of Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) was performed. A search of PubMed online databases was conducted for relevant articles published until November 2014. The reference lists of all retrieved articles were hand-searched. Studies were included after assessing the eligibility of the full-text article. Out of 1078 manuscripts, a total of 157 English written publications were selected based on title and abstract. Of these 157, 60 were included in the study and allocated as 52 MIH and 5 HSPM, and 3 for both MIH and HSPM. These studies utilised the European Academy of Paediatric Dentistry judgment criteria, the modified index of developmental defects of enamel (mDDE) and self-devised criteria, and demonstrated a wide variation in the reported prevalence (MIH 2.9-44 %; HSPM 0-21.8 %). Most values mentioned were representative for specific areas. More studies were performed in cities compared with rural areas. A great variation was found in calibration methods, number of participants, number of examiners and research protocols between the studies. The majority of the prevalence studies also investigated possible aetiological factors. To compare MIH and HSPM prevalence and or aetiological data around the world, standardisation of such studies seems essential. Standardisation of the research protocol should include a clearly described sample of children (minimum number of 300 for prevalence and 1000 for aetiology studies) and use of the same calibration sets and methods whereas aetiological studies need to be prospective in nature. A standardised protocol for future MIH and HSPM prevalence and aetiology studies is recommended. PMID:25894247

  3. Genetic integration of molar cusp size variation in baboons.

    PubMed

    Koh, Christina; Bates, Elizabeth; Broughton, Elizabeth; Do, Nicholas T; Fletcher, Zachary; Mahaney, Michael C; Hlusko, Leslea J

    2010-06-01

    Many studies of primate diversity and evolution rely on dental morphology for insight into diet, behavior, and phylogenetic relationships. Consequently, variation in molar cusp size has increasingly become a phenotype of interest. In 2007 we published a quantitative genetic analysis of mandibular molar cusp size variation in baboons. Those results provided more questions than answers, as the pattern of genetic integration did not fit predictions from odontogenesis. To follow up, we expanded our study to include data from the maxillary molar cusps. Here we report on these later analyses, as well as inter-arch comparisons with the mandibular data. We analyzed variation in two-dimensional maxillary molar cusp size using data collected from a captive pedigreed breeding colony of baboons, Papio hamadryas, housed at the Southwest National Primate Research Center. These analyses show that variation in maxillary molar cusp size is heritable and sexually dimorphic. We also estimated additive genetic correlations between cusps on the same crown, homologous cusps along the tooth row, and maxillary and mandibular cusps. The pattern for maxillary molars yields genetic correlations of one between the paracone-metacone and protocone-hypocone. Bivariate analyses of cuspal homologues on adjacent teeth yield correlations that are high or not significantly different from one. Between dental arcades, the nonoccluding cusps consistently yield high genetic correlations, especially the metaconid-paracone and metaconid-metacone. This pattern of genetic correlation does not immediately accord with the pattern of development and/or calcification, however these results do follow predictions that can be made from the evolutionary history of the tribosphenic molar. PMID:20034010

  4. Erupted complex odontoma delayed eruption of permanent molar.

    PubMed

    Ohtawa, Yumi; Ichinohe, Saori; Kimura, Eri; Hashimoto, Sadamitsu

    2013-01-01

    Odontomas, benign tumors that develop in the jaw, rarely erupt into the oral cavity. We report an erupted odontoma which delayed eruption of the first molar. The patient was a 10-year-old Japanese girl who came to our hospital due to delayed eruption of the right maxillary first molar. All the deciduous teeth had been shed. The second premolar on the right side had erupted, but not the first molar. Slight inflammation of the alveolar mucosa around the first molar had exposed a tooth-like, hard tissue. Panoramic radiography revealed a radiopaque mass indicating a lesion approximately 1 cm in diameter. The border of the image was clear, and part of the mass was situated close to the occlusal surface of the first molar. The root of the maxillary right first molar was only half-developed. A clinical diagnosis of odontoma was made. The odontoma was subsequently extracted, allowing the crown of the first molar to erupt almost 5 months later. The dental germ of the permanent tooth had been displaced by the odontoma. However, after the odontoma had been extracted, the permanent tooth was still able to erupt spontaneously, as eruptive force still remained. When the eruption of a tooth is significantly delayed, we believe that it is necessary to examine the area radiographically. If there is any radiographic evidence of a physical obstruction that might delay eruption, that obstruction should be removed before any problems can arise. Regular dental checkups at schools might improve our ability to detect evidence of delayed eruption earlier. PMID:24521551

  5. Molar Intrusion in Open-bite Adults Using Zygomatic Miniplates.

    PubMed

    Marzouk, Eiman S; Abdallah, Essam Mohamed; El-Kenany, Walid A

    2015-01-01

    The aim of this study is to evaluate the skeletal, dental and soft tissue changes that arise after intrusion of the maxillary molars using zygomatic miniplates in adult skeletal anterior open bite patients. In addition to measuring the amount and rate of molar intrusion; with special emphasis on changes in the axial inclination of the intruded molars. The study group was composed of 13 anterior open bite patients (mean age 18 years, 8 months ± 2 years, 2 months) with posterior dentoalveolar excess. Mini-plates were placed in the zygomatic buttress bilaterally. The upper arch was segmentally leveled and a double Trans-Palatal Arch (TPA) was bonded. Closed NiTi coil spring was placed bilaterally between the book of the mini-plate just mesial and distal to the first molar buccal tube applying intrusive force of 450 gper side. Lateral and posteroanterior cephalograms were taken before intrusion (T1: post upper segmental leveling) and after intrusion (T2). Comparison between means before and after the intrusion was done using Wilcoxon Signed Ranks test (WSRT). Mandibular autorotation followed the molar intrusion, SNB and SN-Pog angles significantly increased while the ANB, MP-SN angle and N-S-Gn angle significantly decreased. The mean amount of accomplished molar intrusion was 3.1mm ± 0.74mm, with a rate of 0.36mm per month ± 0.08mm per month and a bite closure of 6.55mm ± 1.83mm. There was no significant buccal tip in the right and left molars upon intrusion. Conclusion: Miniplates zygomatic anchorage can be used effectively for skeletal open bite correction through posterior dento-alveolar intrusion. Intrusion of the posterior teeth with skeletal anchorage induced counterclockwise rotation of the mandible and, as a consequence, corrected the anteroposterior intermaxillary relationship with a dramatic improvement in the facial soft tissue convexity. PMID:26349291

  6. Genetic integration of molar cusp size variation in baboons

    PubMed Central

    Koh, Christina; Bates, Elizabeth; Broughton, Elizabeth; Do, Nicholas T.; Fletcher, Zachary; Mahaney, Michael C.; Hlusko, Leslea J.

    2010-01-01

    Many studies of primate diversity and evolution rely on dental morphology for insight into diet, behavior, and phylogenetic relationships. Consequently, variation in molar cusp size has increasingly become a phenotype of interest. In 2007 we published a quantitative genetic analysis of mandibular molar cusp size variation in baboons. Those results provided more questions than answers, as the pattern of genetic integration did not fit predictions from odontogenesis. To follow up, we expanded our study to include data from the maxillary molar cusps. Here we report on these later analyses, as well as inter-arch comparisons with the mandibular data. We analyzed variation in two-dimensional maxillary molar cusp size using data collected from a captive pedigreed breeding colony of baboons, Papio hamadryas, housed at the Southwest National Primate Research Center. These analyses show that variation in maxillary molar cusp size is heritable and sexually dimorphic. We also estimated additive genetic correlations between cusps on the same crown, homologous cusps along the tooth row, and maxillary and mandibular cusps. The pattern for maxillary molars yields genetic correlations of one between the paracone-metacone and protocone-hypocone. Bivariate analyses of cuspal homologues on adjacent teeth yield correlations that are high or not significantly different from one. Between dental arcades, the non-occluding cusps consistently yield high genetic correlations, especially the metaconid-paracone and metaconid-metacone. This pattern of genetic correlation does not immediately accord with the pattern of development and/or calcification, however these results do follow predictions that can be made from the evolutionary history of the tribosphenic molar. PMID:20034010

  7. First molar health status in different craniofacial relationships

    PubMed Central

    Linjawi, Amal I

    2016-01-01

    Objective To investigate the association between the health status of permanent first molars and different craniofacial relationships among adolescents. Study design This is a retrospective study on patients’ records aged 11–15 years. Sex, skeletal relationship, vertical growth pattern, malocclusion, overjet, and overbite were assessed. The health status of permanent first molars was recorded from the orthopantomograms and intraoral photographs as “sound” and “not sound”. Chi-square, Mann–Whitney U and Kruskal–Wallis tests, and Pearson’s correlation coefficient were used to analyze and correlate the assessed variables. Significance level was set at P<0.05. Results A total of 210 records were evaluated; 81 were male, 68 had Class I and 91 had Class II skeletal relationships. More than half of the subjects had normal (n=67) to moderate deep bite (n=72); normal (n=91), moderately increased (n=54), to severely increased (n=50) overjet; and Class I (n=106) and Class II division 1 (n=75) malocclusion. Significant differences were found in the health status of the permanent first molars with respect to sex (P=0.034), vertical growth pattern (P=0.01), and overbite (P=0.047). Strong correlations were only found between the health status of the permanent first molars and the following variables: sex (P=0.036) and vertical growth pattern (P=0.004). Significant correlation was further found between the upper left first molar health status and sex (P=0.019) and the lower right first molar health status and the vertical growth pattern (P=0.001). No significant association was found with the anteroposterior craniofacial relationships (P>0.05). Conclusion Sex difference and vertical growth patterns were found to be potential predictors of the health status of the permanent first molars. No significant association was found with the anteroposterior craniofacial relationships. PMID:27462176

  8. Requirement of alveolar bone formation for eruption of rat molars.

    PubMed

    Wise, Gary E; He, Hongzhi; Gutierrez, Dina L; Ring, Sherry; Yao, Shaomian

    2011-10-01

    Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (Bmp6), was inhibited by injection of the first mandibular molar of the rat with a small interfering RNA (siRNA) targeted against Bmp6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption was either delayed or completely inhibited (seven molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced compared with the erupted first-molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that Bmp6 may be essential for promoting this growth. PMID:21896048

  9. Requirement of alveolar bone formation for eruption of rat molars

    PubMed Central

    Wise, Gary E.; He, Hongzhi; Gutierrez, Dina L.; Ring, Sherry; Yao, Shaomian

    2011-01-01

    Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (BMP6), was inhibited by injection of the 1st mandibular molar of the rat with an siRNA targeted against BMP6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption either was delayed or completely inhibited (7 molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced as compared to the erupted first molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that BMP6 may be an essential gene for promoting this growth. PMID:21896048

  10. Orthodontic band retention on primary molar stainless steel crowns.

    PubMed

    Beemer, R L; Ferracane, J L; Howard, H E

    1993-01-01

    The retention of orthodontic bands cemented on primary molar stainless steel crowns (SSC) was studied in vitro. Unitek maxillary and mandibular 1st and 2nd primary molar SSC were fitted with one of four commonly used orthodontic bands (Unitek regular, Unitek narrow, Rocky Mountain, or custom bands made from SSC) using glass ionomer cement. The cemented samples were tested for their resistance to dislodgment on the Instron Universal Testing Machine (Instron Engineering Corp., Canton, MA) in tensile mode. Alpha level for statistical significance was set at alpha = 0.05. Unitek regular bands cemented on the 2nd molar crowns and Unitek narrow bands cemented on the 1st molar crown samples had equivalent or superior resistance to dislodgment compared with the other bands in the study. When the inside of the band and the outside band-bearing surfaces of selected crowns were lightly scored with a diamond bur prior to cementation, samples exhibited significantly superior retention. Subgroup means increased from 107 to 330%, compared to the values obtained in their preroughened state. The mean values obtained using the roughened band/crown interface technique (range 52.9 +/- 7.6 to 73.6 +/- 8.4 lbs) compared favorably with retention values from the literature for orthodontic bands cemented on permanent molar and premolar teeth. PMID:8153003

  11. 3D imaging reconstruction and impacted third molars: case reports

    PubMed Central

    Tuzi, Andrea; Di Bari, Roberto; Cicconetti, Andrea

    2012-01-01

    Summary There is a debate in the literature about the need for Computed Tomagraphy (CT) before removing third molars, even if positive radiographic signs are present. In few cases, the third molar is so close to the inferior alveolar nerve that its extraction might expose patients to the risk of post-operative neuro-sensitive alterations of the skin and the mucosa of the homolateral lower lip and chin. Thus, the injury of the inferior alveolar nerve may represent a serious, though infrequent, neurologic complication in the surgery of the third molars rendering necessary a careful pre-operative evaluation of their anatomical relationship with the inferior alveolar nerve by means of radiographic imaging techniques. This contribution presents two case reports showing positive radiographic signs, which are the hallmarks of a possible close relationship between the inferior alveolar nerve and the third molars. We aim at better defining the relationship between third molars and the mandibular canal using Dental CT Scan, DICOM image acquisition and 3D reconstruction with a dedicated software. By our study we deduce that 3D images are not indispensable, but they can provide a very agreeable assistance in the most complicated cases. PMID:23386934

  12. Pendulum Therapy of Molar Distalization in Mixed Dentition.

    PubMed

    Patil, Raju Umaji; Prakash, Amit; Agarwal, Anshu

    2016-01-01

    Early and timely pedo-orthodontic treatment is aimed at eliminating the disturbances of skeletal or dentoalveolar development, to harmonize the stomatognathic system before the full eruption of all permanent teeth. The advantages of pendulum appliance are its minimal dependence on patient's compliance (child cooperation), ease of fabrication, onetime activation and adjustment of the springs if necessary to correct minor transverse and vertical molar positions. This article reports a successful treatment method of class II malocclusion with pendulum appliance in mixed dentition phase. Distalization of maxillary molar was done, followed by guidance of canine impaction orthodontically and other dental correction using 0.022 MBT appliances. Posttreatment results were stable and remarkable. How to cite this article: Patil RU, Prakash A, Agarwal A. Pendulum Therapy of Molar Distalization in Mixed Dentition. Int J Clin Pediatr Dent 2016;9(1):67-73. PMID:27274159

  13. Pendulum Therapy of Molar Distalization in Mixed Dentition

    PubMed Central

    Prakash, Amit; Agarwal, Anshu

    2016-01-01

    ABSTRACT Early and timely pedo-orthodontic treatment is aimed at eliminating the disturbances of skeletal or dentoalveolar development, to harmonize the stomatognathic system before the full eruption of all permanent teeth. The advantages of pendulum appliance are its minimal dependence on patient’s compliance (child cooperation), ease of fabrication, onetime activation and adjustment of the springs if necessary to correct minor transverse and vertical molar positions. This article reports a successful treatment method of class II malocclusion with pendulum appliance in mixed dentition phase. Distalization of maxillary molar was done, followed by guidance of canine impaction orthodontically and other dental correction using 0.022 MBT appliances. Posttreatment results were stable and remarkable. How to cite this article: Patil RU, Prakash A, Agarwal A. Pendulum Therapy of Molar Distalization in Mixed Dentition. Int J Clin Pediatr Dent 2016;9(1):67-73. PMID:27274159

  14. Aberration in the palatal root of the maxillary first molar

    PubMed Central

    Rajalbandi, Sandeep; Shingte, Sandhya Narayan; Sundaresh, K J; Mallikarjuna, Rachappa

    2013-01-01

    Thorough knowledge of root canal morphology is essential for the endodontic therapy. Variations in the root and root canal morphology, especially in multirooted teeth, are a constant challenge for diagnosis and management. The dentist needs to be familiar with the various root canal configurations and their variations for successful endodontic therapy. There are rare variations in canal number and configuration in maxillary molars, which could affect treatment outcome. Two lingual root structures are occasionally found on human permanent maxillary molars. One of these is the normal lingual root, which is always present, the other is a supernumerary structure which can be located either mesiolingually (radix mesiolingualis) or distolingually (radix distolingualis). The purpose of this paper is to review the literature and to demonstrate a case report which describes the successful non-surgical endodontic management of an unusual maxillary first molar with four separate roots and four canals. PMID:23632609

  15. Molar enamel thickness and dentine horn height in Gigantopithecus blacki.

    PubMed

    Olejniczak, A J; Smith, T M; Wang, W; Potts, R; Ciochon, R; Kullmer, O; Schrenk, F; Hublin, J-J

    2008-01-01

    Absolutely thick molar enamel is consistent with large body size estimates and dietary inferences about Gigantopithecus blacki, which focus on tough or fibrous vegetation. In this study, 10 G. blacki molars demonstrating various stages of attrition were imaged using high-resolution microtomography. Three-dimensional average enamel thickness and relative enamel thickness measurements were recorded on the least worn molars within the sample (n = 2). Seven molars were also virtually sectioned through the mesial cusps and two-dimensional enamel thickness and dentine horn height measurements were recorded. Gigantopithecus has the thickest enamel of any fossil or extant primate in terms of absolute thickness. Relative (size-scaled) measures of enamel thickness, however, support a thick characterization (i.e., not "hyper-thick"); G. blacki relative enamel thickness overlaps slightly with Pongo and completely with Homo. Gigantopithecus blacki dentine horns are relatively short, similar to (but shorter than) those of Pongo, which in turn are shorter than those of humans and African apes. Gigantopithecus blacki molar enamel (and to a lesser extent, that of Pongo pygmaeus) is distributed relatively evenly across the occlusal surface compared with the more complex distribution of enamel thickness in Homo sapiens. The combination of evenly distributed occlusal enamel and relatively short dentine horns in G. blacki results in a flat and low-cusped occlusal surface suitable to grinding tough or fibrous food objects. This suite of molar morphologies is also found to varying degrees in Pongo and Sivapithecus, but not in African apes and humans, and may be diagnostic of subfamily Ponginae. PMID:17941103

  16. Sex assessment by molar odontometrics in North Indian population

    PubMed Central

    Narang, Ramandeep Singh; Manchanda, Adesh S.; Singh, Balwinder

    2015-01-01

    Introduction: Human identification is based on scientific principles, mainly involving dental records, fingerprints, estimation of age, postmortem reports, differentiation by blood groups, and DNA comparisons. Sex assessment is one of the prime factors employed to assist with the identification of an individual. Aims and Objective: To investigate univariate sex differences in the dimensions of permanent first molars and to assess sex, based on buccolingual (BL) and mesiodistal (MD) dimensions of permanent first molars in a population of north India. In addition, the study intended to evaluate the reliability of dimensional variation of these teeth in assessment of sex among the population. Materials and Methods: The study sample consists of 410 adult individuals (200 males and 210 females), from a north Indian population. The BL and MD diameters of the permanent first molars were measured using digital vernier callipers. Results: It was observed statistically significant difference between males and females with P < 0.05, in maxillary casts in both BL and MD dimensions; but only in the MD dimension in mandibular casts. A high level of sexual dimorphism of 7.7% was found in the BL dimension of the maxillary right first molar. The accuracy of sex assessment by each dimension was deliberated by univariate analyses with an overall accuracy ranging from 67.5 to 88% for various dimensions. Conclusion: Sexual dimorphism of teeth is population specific and among north Indian population, BL and MD dimensions in maxillary first molar and MD dimension in mandibular first molar can be used for sex assessment. PMID:25709321

  17. Procedures to recover DNA from pre-molar and molar teeth of decomposed cadavers with different post-mortem intervals.

    PubMed

    Raimann, Paulo E; Picanço, Juliane B; Silva, Deborah S B S; Albuquerque, Trícia C K; Paludo, Francis Jackson O; Alho, Clarice S

    2012-11-01

    A task-force to resolve 26 pending forensic caseworks was carried out. We tested four different protocols to extract DNA from molar and pre-molar teeth from 26 cadavers with post-mortem intervals from 2 months to 12 years. We compared the amount of DNA and DNA profiles with the time elapsed between death and laboratory procedures. Molar or pre-molar teeth were removed from the corpses, cleaned, and DNA was extracted using 2 or 12h of incubation on lysis buffer and filtered using concentration column or precipitated with isopropanol. DNA profiles were obtained using PowerPlex16™ System PCR Amplification Kit, AmpFlSTR(®) Yfiler™ and/or mtDNA sequencing. Complete DNA profiles comparison and statistical evaluation allowed unambiguous identification of the 26 victims. No significant differences were observed in the amount of DNA obtained with the distinct incubation times. The use of concentration column resulted in an increased amount of DNA when compared to isopropanol. However, the lower concentration of DNA obtained with isopropanol seemed to have been compensated by the higher purity. No significant differences in the number of amplified loci were found. A non-significant tendency was found between the amount of total DNA recovered and the time elapsed between death and laboratory procedures. The increase of post-mortem time did not interfere in the analysed autosomal loci. In conclusion, molar and pre-molar teeth were shown to be good candidates to obtain satisfactory DNA profiles, suggesting the high potential of tooth samples as source for DNA typing independently of the decomposed corpse's time or laboratory procedures. PMID:23040740

  18. Management of Six Root Canals in Mandibular First Molar

    PubMed Central

    Gomes, Fabio de Almeida; Sousa, Bruno Carvalho

    2015-01-01

    Success in root canal treatment is achieved after thorough cleaning, shaping, and obturation of the root canal system. This clinical case describes conventional root canal treatment of an unusual mandibular first molar with six root canals. The prognosis for endodontic treatment in teeth with abnormal morphology is unfavorable if the clinician fails to recognize extra root canals. PMID:25685156

  19. The effect of dexamethasone on neurapraxia following third molar surgery.

    PubMed

    Von Arx, D P; Simpson, M T

    1989-12-01

    A double blind, controlled trial was undertaken to assess the effect of intra-muscular dexamethasone on neurapraxia following the surgical removal of mandibular third molars. No significant difference was found 24 h post-operatively between a control group and a group given dexamethasone. PMID:2597658

  20. Survival rates of porcelain molar crowns-an update.

    PubMed

    Kassem, Amr Shebl; Atta, Osama; El-Mowafy, Omar

    2010-01-01

    The aim of this study was to identify recent studies that dealt with the clinical performance of porcelain molar crowns and to explore the possibility of grouping the findings from similar studies together to draw overall conclusions. A MEDLINE literature search was conducted in early 2009 covering the preceding 12 years. Seventeen studies were indentified. However, only seven met the specific inclusion criteria and were analyzed. Among seven studies, five European countries were covered. Five studies reported on Procera AllCeram molar crowns while one reported on In-Ceram Alumina and Spinell crowns and another on CEREC crowns. For comparison, one additional study that reported on premolar crowns was included. In the five Procera AllCeram studies, 235 molar crowns were evaluated for 5 or more years, of which 24 failed. When the results of the five studies on the performance of Procera AllCeram molar crowns were considered collectively, an overall failure rate of 10.2% was found at 5 or more years. Int J Prosthodont 2010;23:60-62. PMID:20234895

  1. A cervical ectopic masquerading as a molar pregnancy.

    PubMed

    Masir, N; Tamby, M R; Jamil, M A

    2000-03-01

    We report a case of cervical pregnancy complicated by life threatening hemorrhage. An initial diagnosis of molar pregnancy was made preoperatively. During uterine evacuation she developed profuse hemorrhage which required an emergency hysterectomy for uncontrolled bleeding. Histopathological examination confirmed a cervical pregnancy. The clinical and pathological criteria for the diagnosis and the etiology of cervical pregnancy are discussed. PMID:11072500

  2. Anterior tympanic plate fracture following extraction of the lower molar

    PubMed Central

    2016-01-01

    The present case report describes an external auditory canal injury following extraction of the lower molar. The external auditory canal was torn in the same fashion that occurs in an anterior tympanic plate fracture. This case demonstrates one of the rare complications associated with dental extractions. PMID:26904496

  3. Intrusion of overerupted molars by corticotomy and magnets.

    PubMed

    Hwang, H S; Lee, K H

    2001-08-01

    Although posterior tooth intrusion in an adult patient is a difficult procedure, it can be achieved without extruding the adjacent teeth by performing a corticotomy and using magnets. In carrying out this procedure on 2 adult patients whose molars had overerupted due to the early loss of antagonists, tooth movement was rapidly achieved without discomfort or side effects. PMID:11500664

  4. Lower molar and incisor displacement associated with mandibular remodeling.

    PubMed

    Baumrind, S; Bravo, L A; Ben-Bassat, Y; Curry, S; Korn, E L

    1997-01-01

    The purpose of this study was to quantify the amount of alveolar modeling at the apices of the mandibular incisor and first molar specifically associated with appositional and resorptive changes on the lower border of the mandible during growth and treatment. Cephalometric data from superimpositions on anterior cranial base, mandibular implants of the Björk type, and anatomical "best fit" of mandibular border structures were integrated using a recently developed strategy, which is described. Data were available at annual intervals between 8.5 and 15.5 years for a previously described sample of approximately 30 children with implants. The average magnitudes of the changes at the root apices of the mandibular first molar and central incisor associated with modeling/remodeling of the mandibular border and symphysis were unexpectedly small. At the molar apex, mean values approximated zero in both anteroposterior and vertical directions. At the incisor apex, mean values approximated zero in the anteroposterior direction and averaged less than 0.15 mm/year in the vertical direction. Standard deviations were roughly equal for the molar and the incisor in both the anteroposterior and vertical directions. Dental displacement associated with surface modeling plays a smaller role in final tooth position in the mandible than in the maxilla. It may also be reasonably inferred that anatomical best-fit superimpositions made in the absence of implants give a more complete picture of hard tissue turnover in the mandible than they do in the maxilla. PMID:9107373

  5. A Time for Heresy: A Molar Reading Model.

    ERIC Educational Resources Information Center

    Williamson, Leon E.

    A survey of the literature concerning the mental processes used in reading reveals a proliferation of molecular theories which explain only a small (and frequently neurological) component of the reading act. Enough information exists, however, to sketch an integrated, molar model of the reading process, which stresses the interrelationships…

  6. Non-compliance Appliances for Upper Molar Distalization: An Overview.

    PubMed

    Noorollahian, Saeed; Alavi, Shiva; Shirban, Farinaz

    2015-01-01

    Tooth Size Arch-length Discrepancy (TSALD) is a common problem in orthodontics. Its clinical signs are tooth crowding, impaction and incisor proclination. The treatment options are dental arch expansion or tooth mass reduction (stripping or extraction). The "extraction versus non-extraction" controversy has been widely debated in the orthodontic literature. Distalization is a kind of arch expansion in anetro-posterior dimension. Several studies have evaluated both the therapeutic effectiveness and the side effects of the appliances for this method of space gaining. In some cases molar distalization is preferred, e.g., a patient with acceptable profile and skeletal pattern and half cusp Class II molar malocclusion or even less. In some cases molar distalization is the only way, e.g., the patient with previous upper premolar extraction and excessive overijet, or a skeletal Class III patient with previous upper premolar extraction needed upper anterior teeth retraction to create reverse overjet aspre surgical orthodontic decompensation. In this review article, we described non-compliance upper molar distalizing appliances. PMID:26720949

  7. Corticotomy-assisted molar protraction with the aid of temporary anchorage device.

    PubMed

    Uribe, Flavio; Janakiraman, Nandakumar; Fattal, Amine N; Schincaglia, Gian Pietro; Nanda, Ravindra

    2013-11-01

    This case report describes the interdisciplinary management of a 58-year-old woman who was missing lower first molars and supraerupted maxillary first molars. The treatment plan included intrusion of the upper first molars and corticotomy-assisted mandibular second molar protraction with the aid of temporary anchorage devices. Miniscrews were effective in intrusion of the maxillary first molars and protraction of the lower second molars. Although good functional outcome was achieved in 41 months, the corticotomy-assisted procedure did not significantly reduce the treatment time. PMID:23834274

  8. Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction

    PubMed Central

    Jiang, Qian; Qiu, Yating; Yang, Chi; Yang, Jingyun; Chen, Minjie; Zhang, Zhiyuan

    2015-01-01

    Abstract Impacted third molars are frequently encountered in clinical work. Surgical removal of impacted third molars is often required to prevent clinical symptoms. Traditional rotary cutting instruments are potentially injurious, and piezosurgery, as a new osteotomy technique, has been introduced in oral and maxillofacial surgery. No consistent conclusion has been reached regarding whether this new technique is associated with fewer or less severe postoperative sequelae after third molar extraction. The aim of this study was to compare piezosurgery with rotary osteotomy techniques, with regard to surgery time and the severity of postoperative sequelae, including pain, swelling, and trismus. We conducted a systematic literature search in the Cochrane Library, PubMed, Embase, and Google Scholar. The eligibility criteria of this study included the following: the patients were clearly diagnosed as having impacted mandibular third molars; the patients underwent piezosurgery osteotomy, and in the control group rotary osteotomy techniques, for removing impacted third molars; the outcomes of interest include surgery time, trismus, swelling or pain; the studies are randomized controlled trials. We used random-effects models to calculate the difference in the outcomes, and the corresponding 95% confidence interval. We calculated the weighted mean difference if the trials used the same measurement, and a standardized mean difference if otherwise. A total of seven studies met the eligibility criteria and were included in our analysis. Compared with rotary osteotomy, patients undergoing piezosurgery experienced longer surgery time (mean difference 4.13 minutes, 95% confidence interval 2.75–5.52, P < 0.0001). Patients receiving the piezoelectric technique had less swelling at postoperative days 1, 3, 5, and 7 (all Ps ≤0.023). Additionally, there was a trend of less postoperative pain and trismus in the piezosurgery groups. The number of included randomized controlled

  9. Exploring metameric variation in human molars: a morphological study using morphometric mapping.

    PubMed

    Morita, Wataru; Morimoto, Naoki; Ohshima, Hayato

    2016-09-01

    Human molars exhibit a type of metameric variation, which is the difference in serially repeated morphology within an organism. Various theories have been proposed to explain how this variation is brought about in the molars. Actualistic data that support the theories, however, are still relatively scarce because of methodological limitations. Here we propose new methods to analyse detailed tooth crown morphologies. We applied morphometric mapping to the enamel-dentine junction of human maxillary molars and examined whether odontogenetic models were adaptable to human maxillary molars. Our results showed that the upper first molar is phenotypically distinct among the maxillary molars. The average shape of the upper first molar is characterized by four well-defined cusps and precipitous surface relief of the occlusal table. On the other hand, upper third molar is characterized by smooth surface relief of the occlusal table and shows greater shape variation and distinct distribution patterns in morphospace. The upper second molar represents an intermediate state between first and third molar. Size-related shape variation was investigated by the allometric vector analysis, and it appeared that human maxillary molars tend to converge toward the shape of the upper first molar as the size increases. Differences between the upper first molar and the upper second and third molar can thus be largely explained as an effect of allometry. Collectively, these results indicate that the observed pattern of metameric variation in human molars is consistent with odontogenetic models of molar row structure (inhibitory cascade model) and molar crown morphology (patterning cascade model). This study shows that morphometric mapping is a useful tool to visualize and quantify the morphological features of teeth, which can provide the basis for a better understanding of tooth evolution linking morphology and development. PMID:27098351

  10. Thermal correction to the molar polarizability of a Boltzmann gas

    SciTech Connect

    Jentschura, U. D.; Puchalski, M.; Mohr, P. J.

    2011-12-15

    Metrology in atomic physics has been crucial for a number of advanced determinations of fundamental constants. In addition to very precise frequency measurements, the molar polarizability of an atomic gas has recently also been measured very accurately. Part of the motivation for the measurements is due to ongoing efforts to redefine the International System of Units (SI), for which an accurate value of the Boltzmann constant is needed. Here we calculate the dominant shift of the molar polarizability in an atomic gas due to thermal effects. It is given by the relativistic correction to the dipole interaction, which emerges when the probing electric field is Lorentz transformed into the rest frame of the atoms that undergo thermal motion. While this effect is small when compared to currently available experimental accuracy, the relativistic correction to the dipole interaction is much larger than the thermal shift of the polarizability induced by blackbody radiation.

  11. Thermal correction to the molar polarizability of a Boltzmann gas

    NASA Astrophysics Data System (ADS)

    Jentschura, U. D.; Puchalski, M.; Mohr, P. J.

    2011-12-01

    Metrology in atomic physics has been crucial for a number of advanced determinations of fundamental constants. In addition to very precise frequency measurements, the molar polarizability of an atomic gas has recently also been measured very accurately. Part of the motivation for the measurements is due to ongoing efforts to redefine the International System of Units (SI), for which an accurate value of the Boltzmann constant is needed. Here we calculate the dominant shift of the molar polarizability in an atomic gas due to thermal effects. It is given by the relativistic correction to the dipole interaction, which emerges when the probing electric field is Lorentz transformed into the rest frame of the atoms that undergo thermal motion. While this effect is small when compared to currently available experimental accuracy, the relativistic correction to the dipole interaction is much larger than the thermal shift of the polarizability induced by blackbody radiation.

  12. Ectopic 3rd Molar Tooth in the Maxillary Antrum

    PubMed Central

    Bello, Seidu A.; Oketade, Ifeoluwa O.; Osunde, Otasowie D.

    2014-01-01

    Location of ectopic tooth in a nondentate area like the maxillary antrum is rare. A 17-year-old boy, with one year history of recurrent right facial swelling and radiographic finding of a maxillary third molar tooth located at the posterior wall of the maxillary antrum, is presented. Under endotracheal intubation, the tooth was extracted through a Caldwell-Luc antrostomy approach and patient had an uneventful recovery and has been symptom free for eight months. Ectopic tooth in the maxillary antrum is rare and is commonest with maxillary third molar. It may be symptomless but is more commonly associated with inflammatory symptoms. The treatment of choice is surgical excision which is mostly carried out with Caldwell-Luc approach, even though endoscopic approach is being reported. PMID:25132999

  13. Ectopic 3rd molar tooth in the maxillary antrum.

    PubMed

    Bello, Seidu A; Oketade, Ifeoluwa O; Osunde, Otasowie D

    2014-01-01

    Location of ectopic tooth in a nondentate area like the maxillary antrum is rare. A 17-year-old boy, with one year history of recurrent right facial swelling and radiographic finding of a maxillary third molar tooth located at the posterior wall of the maxillary antrum, is presented. Under endotracheal intubation, the tooth was extracted through a Caldwell-Luc antrostomy approach and patient had an uneventful recovery and has been symptom free for eight months. Ectopic tooth in the maxillary antrum is rare and is commonest with maxillary third molar. It may be symptomless but is more commonly associated with inflammatory symptoms. The treatment of choice is surgical excision which is mostly carried out with Caldwell-Luc approach, even though endoscopic approach is being reported. PMID:25132999

  14. Fate of the molar dental lamina in the monophyodont mouse.

    PubMed

    Dosedělová, Hana; Dumková, Jana; Lesot, Hervé; Glocová, Kristýna; Kunová, Michaela; Tucker, Abigail S; Veselá, Iva; Krejčí, Pavel; Tichý, František; Hampl, Aleš; Buchtová, Marcela

    2015-01-01

    The successional dental lamina (SDL) plays an essential role in the development of replacement teeth in diphyodont and polyphyodont animals. A morphologically similar structure, the rudimental successional dental lamina (RSDL), has been described in monophyodont (only one tooth generation) lizards on the lingual side of the developing functional tooth. This rudimentary lamina regresses, which has been proposed to play a role in preventing the formation of future generations of teeth. A similar rudimentary lingual structure has been reported associated with the first molar in the monophyodont mouse, and we show that this structure is common to all murine molars. Intriguingly, a lingual lamina is also observed on the non-replacing molars of other diphyodont mammals (pig and hedgehog), initially appearing very similar to the successional dental lamina on the replacing teeth. We have analyzed the morphological as well as ultrastructural changes that occur during the development and loss of this molar lamina in the mouse, from its initiation at late embryonic stages to its disappearance at postnatal stages. We show that loss appears to be driven by a reduction in cell proliferation, down-regulation of the progenitor marker Sox2, with only a small number of cells undergoing programmed cell death. The lingual lamina was associated with the dental stalk, a short epithelial connection between the tooth germ and the oral epithelium. The dental stalk remained in contact with the oral epithelium throughout tooth development up to eruption when connective tissue and numerous capillaries progressively invaded the dental stalk. The buccal side of the dental stalk underwent keratinisation and became part of the gingival epithelium, while most of the lingual cells underwent programmed cell death and the tissue directly above the erupting tooth was shed into the oral cavity. PMID:26010446

  15. Effective molarity in a nucleic acid-controlled reaction.

    PubMed

    Catalano, Michael J; Price, Nathan E; Gates, Kent S

    2016-06-01

    Positioning of reactive functional groups within a DNA duplex can enable chemical reactions that otherwise would not occur to an appreciable extent. However, few studies have quantitatively defined the extent to which the enforced proximity of reaction partners in duplex DNA can favor chemical processes. Here, we measured substantial effective molarities (as high as 25M) afforded by duplex DNA to a reaction involving interstrand cross-link formation between 2'-deoxyadenosine and a 2-deoxyribose abasic (Ap) site. PMID:27117430

  16. Five Canalled and Three-Rooted Primary Second Mandibular Molar

    PubMed Central

    Selvakumar, Haridoss; Kavitha, Swaminathan; Bharathan, Rajendran; Varghese, Jacob Sam

    2014-01-01

    A thorough knowledge of root canal anatomy and its variation is necessary for successful completion of root canal procedures. Morphological variations such as additional root canals in human deciduous dentition are rare. A mandibular second primary molar with more than four canals is an interesting example of anatomic variations, especially when three of these canals are located in the distal root. This case shows a rare anatomic configuration and points out the importance of looking for additional canals. PMID:25147744

  17. The maxillary second molar - anatomical variations (case report).

    PubMed

    Beshkenadze, E; Chipashvili, N

    2015-01-01

    To be acquainted with dental anatomical specificity is of great importance for dental endodontic treatment algorithm. The subject of present publication is 2 clinical cases of upper second molars, detailed characterization of, which is considered very important for enrichment of anatomical knowledge about dental anatomical variations. In one case, the reason for admission to the clinic of a 38-year-old woman was complains as of esthetic character as well as functional misbalance (disturbance of chewing function due to the damage of orthopedic construction). The patient indicated to the existence of coronary defects of large size aesthetic discomforts, damage and discolouration of old orthopedic construction (denture) in maxillary right molar area. According to the data obtained after clinical and visiographical examinations, chronic periodontitis of 17 teeth was identified as a result of incomplete endodontic treatment. According to the data obtained after clinical and visiographical examinations, the diagnosis of chronic periodontitis of 17 teeth was identified, tooth 17 with 2 roots and 2 canals. In the second clinical case, the reason for admission to the clinic of a 39-year-old woman was severe pain in the upper right molar area. The patient indicated to the caries on the tooth 17. After completion of proper survey clinical and visiographical examinations, acute pulpitis (K04.00) - with three roots and 4 canals was diagnosed. In both cases after the proper examinations and agreement with the patients a treatment plan envisaging: 17 teeth endodontic treatment, filling of caries defects and their preparation on one hand for orthopedic construction (denture) and on the other hand for restoration of anatomical integrity by light-cured composite, was scheduled. The present study is designed to prevent complications of endodontic treatment of the second molar, to optimize diagnosis and treatment algorithm, once again proving reliable information indicating to the

  18. Extrusion of impacted mandibular second molar using removable appliance

    PubMed Central

    Karthikeyan, M. K.; Prabhakar, Ramachandran; Saravanan, R.; Vikram, N. Raj; Kumar, R. Vinoth; Prasath, R. Eshwara

    2014-01-01

    The purpose of this article is to review the principles of case management of impacted mandibular molars and to illustrate their potential to respond well to treatment. Although the scope of treatment may be influenced by the patient's age, past dental history, severity of impaction, dentoalveolar development, and root form, the case reports demonstrate the inherent potential for good treatment outcome even in the most unfavorable circumstances. PMID:25210378

  19. Five canalled and three-rooted primary second mandibular molar.

    PubMed

    Selvakumar, Haridoss; Kavitha, Swaminathan; Bharathan, Rajendran; Varghese, Jacob Sam

    2014-01-01

    A thorough knowledge of root canal anatomy and its variation is necessary for successful completion of root canal procedures. Morphological variations such as additional root canals in human deciduous dentition are rare. A mandibular second primary molar with more than four canals is an interesting example of anatomic variations, especially when three of these canals are located in the distal root. This case shows a rare anatomic configuration and points out the importance of looking for additional canals. PMID:25147744

  20. Fate of the Molar Dental Lamina in the Monophyodont Mouse

    PubMed Central

    Dosedělová, Hana; Dumková, Jana; Lesot, Hervé; Glocová, Kristýna; Kunová, Michaela; Tucker, Abigail S.; Veselá, Iva; Krejčí, Pavel; Tichý, František; Hampl, Aleš; Buchtová, Marcela

    2015-01-01

    The successional dental lamina (SDL) plays an essential role in the development of replacement teeth in diphyodont and polyphyodont animals. A morphologically similar structure, the rudimental successional dental lamina (RSDL), has been described in monophyodont (only one tooth generation) lizards on the lingual side of the developing functional tooth. This rudimentary lamina regresses, which has been proposed to play a role in preventing the formation of future generations of teeth. A similar rudimentary lingual structure has been reported associated with the first molar in the monophyodont mouse, and we show that this structure is common to all murine molars. Intriguingly, a lingual lamina is also observed on the non-replacing molars of other diphyodont mammals (pig and hedgehog), initially appearing very similar to the successional dental lamina on the replacing teeth. We have analyzed the morphological as well as ultrastructural changes that occur during the development and loss of this molar lamina in the mouse, from its initiation at late embryonic stages to its disappearance at postnatal stages. We show that loss appears to be driven by a reduction in cell proliferation, down-regulation of the progenitor marker Sox2, with only a small number of cells undergoing programmed cell death. The lingual lamina was associated with the dental stalk, a short epithelial connection between the tooth germ and the oral epithelium. The dental stalk remained in contact with the oral epithelium throughout tooth development up to eruption when connective tissue and numerous capillaries progressively invaded the dental stalk. The buccal side of the dental stalk underwent keratinisation and became part of the gingival epithelium, while most of the lingual cells underwent programmed cell death and the tissue directly above the erupting tooth was shed into the oral cavity. PMID:26010446

  1. 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

  2. Spontaneous emergence of overgrown molar teeth in a colony of Prairie voles (Microtus ochrogaster).

    PubMed

    Jheon, Andrew H; Prochazkova, Michaela; Sherman, Michael; Manoli, Devanand S; Shah, Nirao M; Carbone, Lawrence; Klein, Ophir

    2015-03-01

    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

  3. The Use of Narrow Diameter Implants in the Molar Area.

    PubMed

    Saad, M; Assaf, A; Gerges, E

    2016-01-01

    Implant rehabilitations in the posterior jaw are influenced by many factors such as the condition of the remaining teeth, the force factors related to the patient, the quality of the bone, the maintenance of the hygiene, the limited bone height, the type and extent of edentulism, and the nature of the opposing arch. The gold standard is to place a regular diameter implant (>3.7 mm) or a wide one to replace every missing molar. Unfortunately, due to horizontal bone resorption, this option is not possible without lateral bone augmentation. In this situation, narrow diameter implant (NDI < 3.5 mm) could be the alternative to lateral bone augmentation procedures. This paper presents a clinical study where NDIs were used for the replacement of missing molars. They were followed up to 11 years. Special considerations were observed and many parameters were evaluated. NDI could be used to replace missing molar in case of moderate horizontal bone resorption if strict guidelines are respected. Yet, future controlled prospective clinical trials are required to admit their use as scientific evidence. PMID:27293436

  4. Molar tooth carbonates and benthic methane fluxes in Proterozoic oceans

    NASA Astrophysics Data System (ADS)

    Shen, Bing; Dong, Lin; Xiao, Shuhai; Lang, Xianguo; Huang, Kangjun; Peng, Yongbo; Zhou, Chuanming; Ke, Shan; Liu, Pengju

    2016-01-01

    Molar tooth structures are ptygmatically folded and microspar-filled structures common in early- and mid-Proterozoic (~2,500-750 million years ago, Ma) subtidal successions, but extremely rare in rocks <750 Ma. Here, on the basis of Mg and S isotopes, we show that molar tooth structures may have formed within sediments where microbial sulphate reduction and methanogenesis converged. The convergence was driven by the abundant production of methyl sulphides (dimethyl sulphide and methanethiol) in euxinic or H2S-rich seawaters that were widespread in Proterozoic continental margins. In this convergence zone, methyl sulphides served as a non-competitive substrate supporting methane generation and methanethiol inhibited anaerobic oxidation of methane, resulting in the buildup of CH4, formation of degassing cracks in sediments and an increase in the benthic methane flux from sediments. Precipitation of crack-filling microspar was driven by methanogenesis-related alkalinity accumulation. Deep ocean ventilation and oxygenation around 750 Ma brought molar tooth structures to an end.

  5. Determination of partial molar volumes from free energy perturbation theory†

    PubMed Central

    Vilseck, Jonah Z.; Tirado-Rives, Julian

    2016-01-01

    Partial molar volume is an important thermodynamic property that gives insights into molecular size and intermolecular interactions in solution. Theoretical frameworks for determining the partial molar volume (V°) of a solvated molecule generally apply Scaled Particle Theory or Kirkwood–Buff theory. With the current abilities to perform long molecular dynamics and Monte Carlo simulations, more direct methods are gaining popularity, such as computing V° directly as the difference in computed volume from two simulations, one with a solute present and another without. Thermodynamically, V° can also be determined as the pressure derivative of the free energy of solvation in the limit of infinite dilution. Both approaches are considered herein with the use of free energy perturbation (FEP) calculations to compute the necessary free energies of solvation at elevated pressures. Absolute and relative partial molar volumes are computed for benzene and benzene derivatives using the OPLS-AA force field. The mean unsigned error for all molecules is 2.8 cm3 mol−1. The present methodology should find use in many contexts such as the development and testing of force fields for use in computer simulations of organic and biomolecular systems, as a complement to related experimental studies, and to develop a deeper understanding of solute–solvent interactions. PMID:25589343

  6. Molar tooth carbonates and benthic methane fluxes in Proterozoic oceans

    PubMed Central

    Shen, Bing; Dong, Lin; Xiao, Shuhai; Lang, Xianguo; Huang, Kangjun; Peng, Yongbo; Zhou, Chuanming; Ke, Shan; Liu, Pengju

    2016-01-01

    Molar tooth structures are ptygmatically folded and microspar-filled structures common in early- and mid-Proterozoic (∼2,500–750 million years ago, Ma) subtidal successions, but extremely rare in rocks <750 Ma. Here, on the basis of Mg and S isotopes, we show that molar tooth structures may have formed within sediments where microbial sulphate reduction and methanogenesis converged. The convergence was driven by the abundant production of methyl sulphides (dimethyl sulphide and methanethiol) in euxinic or H2S-rich seawaters that were widespread in Proterozoic continental margins. In this convergence zone, methyl sulphides served as a non-competitive substrate supporting methane generation and methanethiol inhibited anaerobic oxidation of methane, resulting in the buildup of CH4, formation of degassing cracks in sediments and an increase in the benthic methane flux from sediments. Precipitation of crack-filling microspar was driven by methanogenesis-related alkalinity accumulation. Deep ocean ventilation and oxygenation around 750 Ma brought molar tooth structures to an end. PMID:26739600

  7. Molar tooth carbonates and benthic methane fluxes in Proterozoic oceans.

    PubMed

    Shen, Bing; Dong, Lin; Xiao, Shuhai; Lang, Xianguo; Huang, Kangjun; Peng, Yongbo; Zhou, Chuanming; Ke, Shan; Liu, Pengju

    2016-01-01

    Molar tooth structures are ptygmatically folded and microspar-filled structures common in early- and mid-Proterozoic (∼2,500-750 million years ago, Ma) subtidal successions, but extremely rare in rocks <750 Ma. Here, on the basis of Mg and S isotopes, we show that molar tooth structures may have formed within sediments where microbial sulphate reduction and methanogenesis converged. The convergence was driven by the abundant production of methyl sulphides (dimethyl sulphide and methanethiol) in euxinic or H2S-rich seawaters that were widespread in Proterozoic continental margins. In this convergence zone, methyl sulphides served as a non-competitive substrate supporting methane generation and methanethiol inhibited anaerobic oxidation of methane, resulting in the buildup of CH4, formation of degassing cracks in sediments and an increase in the benthic methane flux from sediments. Precipitation of crack-filling microspar was driven by methanogenesis-related alkalinity accumulation. Deep ocean ventilation and oxygenation around 750 Ma brought molar tooth structures to an end. PMID:26739600

  8. Variable permanent mandibular first molar: Review of literature

    PubMed Central

    Ballullaya, Srinidhi V; Vemuri, Sayesh; Kumar, Pabbati Ravi

    2013-01-01

    Introduction: The success of root canal therapy depends on the locations of all the canals, thourough debridement and proper sealing. At times the clinicians are challenged with variations in morphology of root canal. This review article attempts to list out all the variations of permanent mandibular first molar published so for in the literature. Materials and Methods: An exhaustive search was undertaken using PUBMED database to identify published literature from 1900 to 2010 relating to the root canal morphology of permanent first molar by using key words. The selected artcles were obtained and reviewed. Results: Total ninty seven articles were selected out of which 50 were original article and forty seven were case reports. The incidence of third canal in mesial root was 0.95% to 15%. The incidence of three rooted mandibular first molar was 3% to 33%. Only ninety cases reported with c-shape canal configuration. Incidence of Taurodintism without congenital disorder was very rare. Conclusion: The root canal treatment requires proper knowlegde of variations in root canal morphology in order to recognise, disinfect and seal all portal of exit. This can be accomplished with proper diagnosis using newer modes, modification in access preparation, use of operating microscope, enhanced methods of disinfecting and sealing of all canals. PMID:23716959

  9. The Use of Narrow Diameter Implants in the Molar Area

    PubMed Central

    Saad, M.; Assaf, A.; Gerges, E.

    2016-01-01

    Implant rehabilitations in the posterior jaw are influenced by many factors such as the condition of the remaining teeth, the force factors related to the patient, the quality of the bone, the maintenance of the hygiene, the limited bone height, the type and extent of edentulism, and the nature of the opposing arch. The gold standard is to place a regular diameter implant (>3.7 mm) or a wide one to replace every missing molar. Unfortunately, due to horizontal bone resorption, this option is not possible without lateral bone augmentation. In this situation, narrow diameter implant (NDI < 3.5 mm) could be the alternative to lateral bone augmentation procedures. This paper presents a clinical study where NDIs were used for the replacement of missing molars. They were followed up to 11 years. Special considerations were observed and many parameters were evaluated. NDI could be used to replace missing molar in case of moderate horizontal bone resorption if strict guidelines are respected. Yet, future controlled prospective clinical trials are required to admit their use as scientific evidence. PMID:27293436

  10. From molecular to molar: a paradigm shift in behavior analysis.

    PubMed Central

    Baum, William M

    2002-01-01

    A paradigm clash is occurring within behavior analysis. In the older paradigm, the molecular view, behavior consists of momentary or discrete responses that constitute instances of classes. Variation in response rate reflects variation in the strength or probability of the response class. The newer paradigm, the molar view, sees behavior as composed of activities that take up varying amounts of time. Whereas the molecular view takes response rate and choice to be "derived" measures and hence abstractions, the molar view takes response rate and choice to be concrete temporally extended behavioral allocations and regards momentary "responses" as abstractions. Research findings that point to variation in tempo, asymmetry in concurrent performance, and paradoxical resistance to change are readily interpretable when seen in the light of reinforcement and stimulus control of extended behavioral allocations or activities. Seen in the light of the ontological distinction between classes and individuals, extended behavioral allocations, like species in evolutionary taxonomy, constitute individuals, entities that change without changing their identity. Seeing allocations as individuals implies that less extended activities constitute parts of larger wholes rather than instances of classes. Both laboratory research and everyday behavior are explained plausibly in the light of concrete extended activities and their nesting. The molecular- view, because it requires discrete responses and contiguous events, relies on hypothetical stimuli and consequences to account for the same phenomena. One may prefer the molar view on grounds of elegance, integrative power, and plausibility. PMID:12144313

  11. Determination of partial molar volumes from free energy perturbation theory.

    PubMed

    Vilseck, Jonah Z; Tirado-Rives, Julian; Jorgensen, William L

    2015-04-01

    Partial molar volume is an important thermodynamic property that gives insights into molecular size and intermolecular interactions in solution. Theoretical frameworks for determining the partial molar volume (V°) of a solvated molecule generally apply Scaled Particle Theory or Kirkwood-Buff theory. With the current abilities to perform long molecular dynamics and Monte Carlo simulations, more direct methods are gaining popularity, such as computing V° directly as the difference in computed volume from two simulations, one with a solute present and another without. Thermodynamically, V° can also be determined as the pressure derivative of the free energy of solvation in the limit of infinite dilution. Both approaches are considered herein with the use of free energy perturbation (FEP) calculations to compute the necessary free energies of solvation at elevated pressures. Absolute and relative partial molar volumes are computed for benzene and benzene derivatives using the OPLS-AA force field. The mean unsigned error for all molecules is 2.8 cm(3) mol(-1). The present methodology should find use in many contexts such as the development and testing of force fields for use in computer simulations of organic and biomolecular systems, as a complement to related experimental studies, and to develop a deeper understanding of solute-solvent interactions. PMID:25589343

  12. Molar Macrowear Reveals Neanderthal Eco-Geographic Dietary Variation

    PubMed Central

    Fiorenza, Luca; Benazzi, Stefano; Tausch, Jeremy; Kullmer, Ottmar; Bromage, Timothy G.; Schrenk, Friedemann

    2011-01-01

    Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources. PMID:21445243

  13. Primate molar crown formation times and life history evolution revisited.

    PubMed

    Macho, G A

    2001-12-01

    Comparative studies have convincingly demonstrated that the pattern and timing of tooth emergence are highly correlated with life-history variables and brain size. Conversely, a firm relationship between molar formation time and life-history variables has not yet been established. It seems counterintuitive that one aspect of dental development should be correlated with life-history variables, whereas the other should not. In order to shed light on this apparent discrepancy this study analyzed all data on primate molar crown formations available in the published literature in relation to life-history variables, brain size, and female body mass. Crown formation times were found to be particularly highly correlated with both female body mass and brain size. Species that depart from the overall brain/body allometry by being relatively large-bodied, e.g., Gorilla gorilla and later Theropithecus oswaldi, also have shorter molar crown formation times than expected. The reverse is not found for species that depart from the overall brain/body allometry due to their larger brains, i.e., Homo sapiens. This finding is interpreted within an evolutionary and ecological framework. Specifically, by focusing on ecological commonalities, a scenario is proposed which may allow predictions to be made about the evolutionary history of other extinct primates also. If confirmed in future studies, crown formation time may again become a powerful tool in evolutionary enquiry. PMID:11748692

  14. Efficacy of Postoperative Prophylactic Antibiotic Therapy in Third Molar Surgery

    PubMed Central

    Reddy B, Praveen

    2014-01-01

    Introduction: Surgical extraction of mandibular third molar is the most frequently performed procedure in oral surgery. This procedure is associated with significant postoperative sequelae such as trismus, swelling, pain and infection. The need of antibiotic therapy during the removal of mandibular third molar has been a contentious issue. Method: This study investigated a regimen by using amoxycillin and metronidazole in one group and without using antibiotics in the other. Both the groups were assessed postoperatively on the 1st, 2nd, 5th, 7th and 10th days by the same observer for post operative mouth opening (interincisal distance), presence of a purulent discharge at the site of surgery, pain and swelling. Result: Overall, no statistically significant difference was seen between both the treatment groups when interincisal distance, pain, swelling and purulent discharge were considered. Conclusion: The results of this study failed to show any advantage which was associated with the routine postoperative use of antibiotics in asymptomatic third molar surgeries. PMID:24995236

  15. 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

  16. Molar Mass and Second Virial Coefficient of Polyethylene Glycol by Vapor Pressure Osmometry

    ERIC Educational Resources Information Center

    Schwinefus, Jeffrey J.; Checkal, Caleb; Saksa, Brian; Baka, Nadia; Modi, Kalpit; Rivera, Carlos

    2015-01-01

    In this laboratory experiment, students determine the number-average molar masses and second virial coefficients of polyethylene glycol (PEG) polymers ranging in molar mass from 200 to 1500 g mol[superscript -1] using vapor pressure osmometry (VPO). Students assess VPO in relation to accurate molar mass calculations of PEG polymers. Additionally,…

  17. Sub-10-Minute Characterization of an Ultrahigh Molar Mass Polymer by Multi-detector Hydrodynamic Chromatography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molar mass averages, distributions, and architectural information of polymers are routinely obtained using size-exclusion chromatography (SEC). It has previously been shown that ultrahigh molar mass polymers may experience degradation during SEC analysis, leading to inaccurate molar mass averages a...

  18. Mandibular third molar development after mantle radiation in long-term survivors of childhood Hodgkin's disease

    SciTech Connect

    McGinnis, J.P. Jr.; Hopkins, K.P.; Thompson, E.I.; Hustu, H.O.

    1987-05-01

    Sequential panoramic radiographs were assessed for mandibular third molar development in 47 long-term survivors of childhood Hodgkin's disease after treatment with 37 Gy mantle field radiation. To make a comparison, panoramic radiographs of 149 healthy, nonirradiated children were reviewed for the presence of mandibular third molars. In children between the ages of 7 and 12 years, bilateral agenesis of mandibular third molars was more frequent in patients who had been treated with mantle radiation than in nonirradiated patients. Unilateral agenesis, crown hypoplasia, and root growth impairment of mandibular third molars were also found. Similar, apparent, radiation-induced developmental anomalies were noted in maxillary third molars of the irradiated patients.

  19. Compensation trends of the angulation of first molars: retrospective study of 1 403 malocclusion cases

    PubMed Central

    Su, Hong; Han, Bing; Li, Sa; Na, Bin; Ma, Wen; Xu, Tian-Min

    2014-01-01

    We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1 403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First, angulation of the upper first molar varied significantly with age and tipped most distally in cases aged <12 years and least distally in cases aged >16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability. PMID:24699185

  20. Patterning by heritage in mouse molar row development

    PubMed Central

    Prochazka, Jan; Pantalacci, Sophie; Churava, Svatava; Rothova, Michaela; Lambert, Anne; Lesot, Hervé; Klein, Ophir; Peterka, Miroslav; Laudet, Vincent; Peterkova, Renata

    2010-01-01

    It is known from paleontology studies that two premolars have been lost during mouse evolution. During mouse mandible development, two bud-like structures transiently form that may represent rudimentary precursors of the lost premolars. However, the interpretation of these structures and their significance for mouse molar development are highly controversial because of a lack of molecular data. Here, we searched for typical tooth signaling centers in these two bud-like structures, and followed their fate using molecular markers, 3D reconstructions, and lineage tracing in vitro. Transient signaling centers were indeed found to be located at the tips of both the anterior and posterior rudimentary buds. These centers expressed a similar set of molecular markers as the “primary enamel knot” (pEK), the signaling center of the first molar (M1). These two transient signaling centers were sequentially patterned before and anterior to the M1 pEK. We also determined the dynamics of the M1 pEK, which, slightly later during development, spread up to the field formerly occupied by the posterior transient signaling center. It can be concluded that two rudimentary tooth buds initiate the sequential development of the mouse molars and these have previously been mistaken for early stages of M1 development. Although neither rudiment progresses to form an adult tooth, the posterior one merges with the adjacent M1, which may explain the anterior enlargement of the M1 during mouse family evolution. This study highlights how rudiments of lost structures can stay integrated and participate in morphogenesis of functional organs and help in understanding their evolution, as Darwin suspected long ago. PMID:20709958

  1. Patterning by heritage in mouse molar row development.

    PubMed

    Prochazka, Jan; Pantalacci, Sophie; Churava, Svatava; Rothova, Michaela; Lambert, Anne; Lesot, Hervé; Klein, Ophir; Peterka, Miroslav; Laudet, Vincent; Peterkova, Renata

    2010-08-31

    It is known from paleontology studies that two premolars have been lost during mouse evolution. During mouse mandible development, two bud-like structures transiently form that may represent rudimentary precursors of the lost premolars. However, the interpretation of these structures and their significance for mouse molar development are highly controversial because of a lack of molecular data. Here, we searched for typical tooth signaling centers in these two bud-like structures, and followed their fate using molecular markers, 3D reconstructions, and lineage tracing in vitro. Transient signaling centers were indeed found to be located at the tips of both the anterior and posterior rudimentary buds. These centers expressed a similar set of molecular markers as the "primary enamel knot" (pEK), the signaling center of the first molar (M1). These two transient signaling centers were sequentially patterned before and anterior to the M1 pEK. We also determined the dynamics of the M1 pEK, which, slightly later during development, spread up to the field formerly occupied by the posterior transient signaling center. It can be concluded that two rudimentary tooth buds initiate the sequential development of the mouse molars and these have previously been mistaken for early stages of M1 development. Although neither rudiment progresses to form an adult tooth, the posterior one merges with the adjacent M1, which may explain the anterior enlargement of the M1 during mouse family evolution. This study highlights how rudiments of lost structures can stay integrated and participate in morphogenesis of functional organs and help in understanding their evolution, as Darwin suspected long ago. PMID:20709958

  2. Cameriere's third molar maturity index in assessing age of majority.

    PubMed

    Galić, Ivan; Lauc, Tomislav; Brkić, Hrvoje; Vodanović, Marin; Galić, Elizabeta; Biazevic, Maria Gabriela Haye; Brakus, Ivan; Badrov, Jozo; Cameriere, Roberto

    2015-07-01

    Estimation of chronological age of an individual is one of the main challenges in forensic science. Legally to be able to treat a person as a minor or an adult, it is necessary to determine whether their age of majority (if they are older or younger than 18, in most countries). Methods for estimating age are especially important when an individual in question lacks personal documents or other means of identification. As the dental age differs in various populations, the aim of this study was to evaluate applicability of third molar method for assessing age of majority in Croatia. Cameriere's third molar maturity index (I3M) value of 0.08, measured by the open apices of the teeth, was verified in sample of 1336 panoramic images aged between 14 and 23 years. Chronological age gradually decreased as I3M increased in both genders. Males showed statistically significant advanced maturation when I3M was between 0.0 and 0.3 value. The results indicate that the sensitivity of the test for 0.08 value was 84.3% (95%CI 80.6%, 87.5%) for females and 91.2% (95%CI 88.7%, 93.1) for males. Specificity was 95.4% (95%CI 92.5%, 97.5%) and 91.9% (95%CI 88.8%, 94.3%). The proportions of accurately classified males were 88.8% and that of females 91.5%. The estimated post-test probabilities, of individuals, in other word the probability that a Croatian individual with an I3M<0.08 is 18 years or older is 94.5% for females, and 96.5% for males. With high accuracy, the third molar maturity index should be used as a determinant of the age of majority in Croatia. PMID:26013667

  3. Restoration of Endodontically Treated Molars Using All Ceramic Endocrowns

    PubMed Central

    Carlos, Roopak Bose; Thomas Nainan, Mohan; Pradhan, Shamina; Roshni Sharma; Benjamin, Shiny; Rose, Rajani

    2013-01-01

    Clinical success of endodontically treated posterior teeth is determined by the postendodontic restoration. Several options have been proposed to restore endodontically treated teeth. Endocrowns represent a conservative and esthetic restorative alternative to full coverage crowns. The preparation consists of a circular equigingival butt-joint margin and central retention cavity into the entire pulp chamber constructing both the crown and the core as a single unit. The case reports discussed here are moderately damaged endodontically treated molars restored using all ceramic endocrowns fabricated using two different systems, namely, CAD/CAM and pressed ceramic. PMID:24455318

  4. Histological evaluation of mandibular third molar roots retrieved after coronectomy.

    PubMed

    Patel, Vinod; Sproat, Chris; Kwok, Jerry; Beneng, Kiran; Thavaraj, Selvam; McGurk, Mark

    2014-05-01

    There is a resurgence of interest in coronectomy for the management of mandibular third molars because it has a low risk of injury to the inferior dental nerve. However, there is concern that the root that is left in place will eventually become a source of infection. We describe the histological evaluation of 26 consecutive symptomatic coronectomy roots in 21 patients. All roots had vital tissue in the pulp chamber and there was no evidence of periradicular inflammation. Persistent postoperative symptoms related predominantly to inflammation of the soft tissue, which was caused by partially erupted roots or failure of the socket to heal. PMID:24684971

  5. Why, what and how: caries control for erupting molars.

    PubMed

    Rogers, Helen J; Morgan, Annie G; Batley, Haris; Deery, Chris

    2015-03-01

    This article aims to update the practitioner on the various techniques and interventions available to prevent or control caries during this high-risk period. The evidence to support provision of toothbrushing advice, placement of fissure sealants and fluoride varnish application is considered, along with more novel methods. An evidence-based protocol is suggested to help the practitioner determine when further intervention is required and what action to undertake. Clinical Relevance: This article aims to reinforce the need for rigorous caries prevention in an erupting permanent molar and provides an update on the evidence behind a range of clinical techniques used for this purpose. PMID:26058229

  6. The topography of the furcation entrance in Chinese molars. Furcation entrance dimensions.

    PubMed

    Hou, G L; Chen, S F; Wu, Y M; Tsai, C C

    1994-08-01

    The purpose of the present study was to document the furcation entrance dimensions (FEDs) of the maxillary and mandibular 1st and 2nd molars and relate them to the choice of periodontal therapy. Study samples consisted of 89 maxillary molars (49 1st and 40 2nd molars) and 93 mandibular molars (50 1st and 43 2nd molars). All the FEDs of the molars were examined and measured under a stereomicroscope at 2.5 x equipped with a Bioscan OPTIMAS Image Analyzer (BOIA). The results may be summarized as follows. (1) The mean FEDs in the buccal, distal and mesial furcations of maxillary 1st and 2nd molars were 0.74 mm, 0.99 mm and 1.04 mm in the 1st molars, and 0.63 mm, 0.67 mm, 0.90 mm in the 2nd molars, respectively. In the buccal and lingual furcations of mandibular 1st and 2nd molars, they measured 0.88 mm and 0.81 mm, and 0.73 mm and 0.71 mm, respectively. (2) The %s of FEDs of 0.56 mm or less (the tip width of a Cavitron tip being 0.56 mm) in the buccal, distal and mesial furcations of maxillary 1st and 2nd molars, accounted for 32%, 8% and 6% of 1st molars, and 40%, 40% and 18% of 2nd molars. In the buccal and lingual areas of mandibular 1st and 2nd molars, they accounted for 16% and 26%, and 35% and 33% of the furcations, respectively.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7929856

  7. Replantation of a maxillary second molar after removal of a third molar with a dentigerous cyst: Case report and 12-month follow-up

    PubMed Central

    Peñarrocha-Diago, María A.; Peñarrocha-Oltra, David; Peñarrocha-Diago, Miguel

    2014-01-01

    The aim of this study was to describe the replantation of a maxillary second right molar, which had been removed for surgical reasons in order to remove a dentigerous cyst associated with the adjacent third molar, and the case’s 12-month follow-up. A 51-year-old man presented swelling in the right maxillary area. Radiographic examination showed a large radiolucency in close proximity to the third molar, suggesting a follicular cyst. The third molar was extracted and the cyst underwent curettage. The second molar had to be extracted to enable complete removal of the cyst and to achieve primary closure of the wound, which would have been impossible without repositioning the molar. With this objective, extraoral endodontic treatment was performed, the root-end was resected and prepared with ultrasonic retrotips, and root-end filling was accomplished with MTA before the molar was replanted. At the 12-month follow-up, the tooth showed no clinical signs or symptoms, probing depth was no greater than 3 mm and radiographic examination showed no evidence of root resorption or periapical lesion. Key words:Replantation, maxillary molar, follicular cyst, dentigerous cyst. PMID:24790721

  8. Unilateral failure of development of mandibular premolars and molars in an Eastern Grey kangaroo (Macropus giganteus) and its effects on molar progression.

    PubMed

    Barber, D; Campbell, J; Davey, J; Luke, T; Agren, E; Beveridge, I

    2008-01-01

    An adult male Eastern Grey kangaroo from a wildlife reserve near Melbourne was submitted for necropsy examination and was discovered to have abnormal dentition. There was no evidence that any premolars or molars had ever been present on the right mandible, whilst the incisors were normal. The age of the kangaroo was estimated to be 1 year 9 months using the right maxillary molars and 2 years 4 months old using the contralateral side, presumably due to the asymmetry of the dental arcades. 'Lumpy jaw', a common periodontal disease of kangaroos, from which Bacteroides sp was cultured, was present on the base of the vertical ramus of the left mandible. Complete unilateral absence of premolar and molar teeth in the mandible of a kangaroo has not been described. This condition affected molar progression in both sets of maxillary molars. PMID:18271832

  9. Enamel thickness trends in Plio-Pleistocene hominin mandibular molars.

    PubMed

    Skinner, Matthew M; Alemseged, Zeresenay; Gaunitz, Charleen; Hublin, Jean-Jacques

    2015-08-01

    Enamel thickness continues to be an important morphological character in hominin systematics and is frequently invoked in dietary reconstructions of Plio-Pleistocene hominin taxa. However, to date, the majority of published data on molar enamel thickness of Pliocene and early Pleistocene hominins derive from naturally fractured random surfaces of a small number of specimens. In this study we systematically analyze enamel thickness in a large sample of Plio-Pleistocene fossil hominins (n = 99), extant hominoids (n = 57), and modern humans (n = 30). Based on analysis of 2D mesial planes of section derived from microtomography, we examine both average and relative enamel thickness, and the distribution of enamel across buccal, occlusal, and lingual components of mandibular molars. Our results confirm the trend of increasing enamel thickness during the Pliocene that culminates in the thick enamel of the robust Australopithecus species, and then decreases from early Homo to recent modern humans. All hominin taxa share a regional average enamel thickness pattern of thick occlusal enamel and greater buccal than lingual enamel thickness. Pan is unique in exhibiting the thinnest average enamel thickness in the occlusal basin. Statistical analysis indicates that among Pliocene hominins enamel thickness is a weak taxonomic discriminator. The data underlying these results are included in a table in the Supplementary Online Material. PMID:26024565

  10. A geometric morphometric analysis of hominin upper first molar shape.

    PubMed

    Gómez-Robles, A; Martinón-Torres, M; Bermúdez de Castro, J M; Margvelashvili, A; Bastir, M; Arsuaga, J L; Pérez-Pérez, A; Estebaranz, F; Martínez, L M

    2007-09-01

    Recent studies have revealed interesting differences in upper first molar morphology across the hominin fossil record, particularly significant between H. sapiens and H. neanderthalensis. Usually these analyses have been performed by means of classic morphometric methods, including the measurement of relative cusp areas or the angles defined between cusps. Although these studies have provided valuable information for the morphological characterization of some hominin species, we believe that the analysis of this particular tooth could be more conclusive for taxonomic assignment. In this study, we have applied geometric morphometric methods to explore the morphological variability of the upper first molar (M(1)) across the human fossil record. Our emphasis focuses on the study of the phenetic relationships among the European middle Pleistocene populations (designated as H. heidelbergensis) with H. neanderthalensis and H. sapiens, but the inclusion of Australopithecus and early Homo specimens has helped us to assess the polarity of the observed traits. H. neanderthalensis presents a unique morphology characterized by a relatively distal displacement of the lingual cusps and protrusion in the external outline of a large and bulging hypocone. This morphology can be found in a less pronounced degree in the European early and middle Pleistocene populations, and reaches its maximum expression with the H. neanderthalensis lineage. In contrast, modern humans retain the primitive morphology with a square occlusal polygon associated with a round external outline. PMID:17599390

  11. Evolutionary novelty in a rat with no molars

    PubMed Central

    Esselstyn, Jacob A.; Achmadi, Anang Setiawan; Rowe, Kevin C.

    2012-01-01

    Rodents are important ecological components of virtually every terrestrial ecosystem. Their success is a result of their gnawing incisors, battery of grinding molars and diastema that spatially and functionally separates the incisors from the molars. Until now these traits defined all rodents. Here, we describe a new species and genus of shrew-rat from Sulawesi Island, Indonesia that is distinguished from all other rodents by the absence of cheek teeth. Moreover, rather than gnawing incisors, this animal has bicuspid upper incisors, also unique among the more than 2200 species of rodents. Stomach contents from a single specimen suggest that the species consumes only earthworms. We posit that by specializing on soft-bodied prey, this species has had no need to process food by chewing, allowing its dentition to evolve for the sole purpose of procuring food. Thus, the removal of functional constraints, often considered a source of evolutionary innovations, may also lead to the loss of the very same traits that fuelled evolutionary diversification in the past. PMID:22915626

  12. Nanoparticle Counting: Towards Accurate Determination of the Molar Concentration

    PubMed Central

    Shang, Jing; Gao, Xiaohu

    2014-01-01

    Summary Innovations in nanotechnology have brought tremendous opportunities for the advancement of many research frontiers, ranging from electronics, photonics, energy, to medicine. To maximize the benefits of nano-scaled materials in different devices and systems, precise control of their concentration is a prerequisite. While concentrations of nanoparticles have been provided in other forms (e.g., mass), accurate determination of molar concentration, arguably the most useful one for chemical reactions and applications, has been a major challenge (especially for nanoparticles smaller than 30 nm). Towards this significant yet chronic problem, a variety of strategies are currently under development. Most of these strategies are applicable to a specialized group of nanoparticles due to their restrictions on the composition and size ranges of nanoparticles. As research and uses of nanomaterials being explored in an unprecedented speed, it is necessary to develop universal strategies that are easy to use, and compatible with nanoparticles of different sizes, compositions, and shapes. This review outlines the theories and applications of current strategies to measure nanoparticle molar concentration, discusses the advantages and limitations of these methods, and provides insights into future directions. PMID:25099190

  13. Ameloblastin and amelogenin expression in posnatal developing mouse molars.

    PubMed

    Torres-Quintana, María Angélica; Gaete, Marcia; Hernandez, Marcela; Farías, Marcela; Lobos, Nelson

    2005-03-01

    Ameloblastin and amelogenin are structural proteins present in the enamel matrix of developing teeth. Here we report the results of in situ hybridization analyses with DNA probes of ameloblastin and amelogenin expression in the mandibular first molars of ICR/Jcl mice from postnatal day 1 to day 15. Ameloblastin mRNA expression was observed in ameloblasts at day 2 while amelogenin mRNA was detected in secretory ameloblasts at day 3. Significant expression of both molecules was observed at days 4, 5 and 6, after which the levels decreased. Amelogenin expression ended on day 10, while ameloblastin mRNA was only weakly detected on day 12. Neither amelogenin nor ameloblastin expression was observed in day 15 mouse molars. Amelogenin and ameloblastin mRNAs were restricted to ameloblasts. We conclude that amelogenin and ameloblastin expression is enamel-specific, and suggest that these genes might be involved in the mineralization of enamel. It is possible that ameloblastin could participate in the attachment of ameloblasts to the enamel surface. In this case, the downregulation of expression may indicate the beginning of the maturation stage in which the ameloblasts tend to detach from the enamel layer. PMID:15881226

  14. Etiology, Classification and Management of Ectopic Eruption of Permanent First Molars.

    PubMed

    Hsiao, Chu-Chun; Boynton, James R

    2016-01-01

    Ectopic eruption of a permanent tooth involves abnormal resorption of a portion or all of the adjacent primary tooth. Among the most commonly ectopically erupted teeth are the permanent first molars. Ectopically erupting molars may require intervention to allow for full eruption, or they may spontaneously self-correct and erupt into occlusion. Decisions regarding the necessity of intervention, its ideal timing, and intervention type are multifactorial. Treatment options for the ectopically erupting permanent first molar include the elastomeric separator, brass wire, pre-fabricated clip separator, custom made appliances (Humphrey appliance, Halterman appliance), or extraction of the primary molar. Early intervention when indicated can ensure proper full eruption of the permanent first molar and prevent mesial angulation, arch perimeter loss, tooth impaction and ankylosis. Two cases are described that manage ectopic eruption of the permanent first molar. PMID:26882645

  15. Efficiency of two protocols for maxillary molar intrusion with mini-implants

    PubMed Central

    Paccini, Juliana Volpato Curi; Cotrim-Ferreira, Flávio Augusto; Ferreira, Flávio Vellini; de Freitas, Karina Maria Salvatore; Cançado, Rodrigo Hermont; Valarelli, Fabrício Pinelli

    2016-01-01

    ABSTRACT Objective: The aim of this study was to compare the efficiency of two protocols for maxillary molar intrusion with two or three mini-implants. Methods: Twenty five maxillary first molars extruded for loss of their antagonists in adult subjects were selected. The sample was divided into two groups, according to the intrusion protocol with two or three mini-implants. Group 1 consisted of 15 molars that were intruded by two mini-implants. Group 2 consisted of 10 molars intruded by three mini-implants. Changes with treatment were analyzed in lateral cephalograms at the beginning and at the end of intrusion of maxillary molars. Results: Results showed that there was no difference in efficiency for the two intrusion protocols. It was concluded that extruded maxillary molars can be intruded with two or three mini-implants with similar efficiency. PMID:27409654

  16. Ectopic third molar in the mandibular sigmoid notch: Report of a case and literature review

    PubMed Central

    Baykul, Timuçin

    2015-01-01

    Purpose: To evaluate the etiopathogenesis, clinical features and surgical approaches for removal of ectopic third molars in the mandible. Methods: We report a case of an impacted mandibular third molar dislocated on mandibular sigmoid notch. 20 cases of ectopic mandibular third molars reported in the English-language literature, identified from Pubmed and Medline databases are also reviewed. Results: Among the 20 article reported in the presented study, ectopic third molars were generally located in the condylar region. The common symptoms of the clinical examination were pain, trismus, swelling, temporomandibular joint syndroms or no symptoms. Conclusions: Ectopic third molar may be asymptomatic initially with clinical manifestations, later on as adjacent structures are affected. The surgical approach must be carefully planned for the aim of choosing the more conservative technique that produces the minimum trauma to patients. Key words:Ectopic third molar, sigmoid notch, cyst. PMID:25810825

  17. Molar extinction coefficients of solutions of some organic compounds

    NASA Astrophysics Data System (ADS)

    Singh, Kulwant; Sandhu, G. K.; Lark, B. S.

    2004-05-01

    Molar extinction coefficients of aqueous solutions of some organic compounds, viz. formamide (CH_{3}NO), N-methylformamide (C_{2}H_{5}NO), NN-dimethylformamide (C_{3}H_{7}NO), NN-dimethylacetamide (C_{4}H_{9}NO), 1,4-dioxane (C_{4}H_{8}O_{2}), succinimide (C_{4}H_{5}NO_{2}) and solutions of acetamide (C_{2}H_{5}NO) and benzoic acid (C_{7}H_{6}O_{2}) in 1,4-dioxane (C_{4}H_{8}O_{2}) have been determined by narrow beam gamma-ray transmission method at 81, 356, 511, 662, 1173 and 1332 keV. The experimental values of mass attenuation coefficients of these compounds have been used to calculate effective atomic numbers and electron densities. The additivity rule earlier used for aqueous solution has been extended to non-aqueous (1,4-dioxane) solutions.

  18. Analgesic regimens for third molar surgery: pharmacologic and behavioral considerations.

    PubMed

    Moore, P A; Werther, J R; Seldin, E B; Stevens, C M

    1986-11-01

    The level of pain following the extraction of impacted third molars was evaluated in 75 patients. Participants were administered acetaminophen 1,000 mg or a placebo before surgery. After surgery, acetaminophen 650 mg was administered either at fixed intervals or as needed to relieve pain. When acetaminophen was administered before surgery, the onset of peak pain was delayed and patient discomfort was decreased 3, 4, and 5 hours after surgery. Patients following the fixed interval regimen after surgery experienced more pain overall and requested the backup narcotic analgesic more frequently. Of the regimens tested, patients preferred the regimen of acetaminophen 1,000 mg administered before surgery with acetaminophen administered as needed for pain after surgery. PMID:3465787

  19. Third molar consent forms: how comprehensive should they be?

    PubMed

    Britton, Danielle; Burns, Andrew; Hudyba, Stephen; Nugent, Michael

    2016-09-01

    To establish a gold standard for the information given to patients about the risks associated with third molar extractions, we surveyed 79 oral and maxillofacial surgeons (OMFS) to find out what information they gave to patients during the consent process. We also surveyed 62 medicolegal solicitors to find out what information they thought patients should be given before the procedure, and in what form. A total of 20/76 OMFS (26%) used a two-stage process to obtain consent; 13 (17%) included paraesthesia on the consent form and also gave out an information leaflet. All the lawyers agreed that patients should give their consent in writing and thought that the risk of paraesthesia should be included on the form. Three-quarters thought that they should also be given an information leaflet that includes paraesthesia. We encourage surgeons to do this as part of the two-stage consent process. PMID:27256800

  20. Partial molar volume of L-Valine in water under high pressure

    NASA Astrophysics Data System (ADS)

    Sawamura, Seiji

    2013-06-01

    Partial molar volume of L-valine in water was estimated up to 400 MPa from pressure coefficient of the solubility of the solute and molar volume of solid valine. The former was measured in a previous paper and the latter was measured in this article using a piston-cylinder typed cell. The partial molar volume increased with pressure and a maximum was observed around 250 MPa. It was compared with other amino acids.

  1. Three-rooted mandibular first primary molar: Report of three cases

    PubMed Central

    Gupta, Shilpi; Nagaveni, N. B.; Chandranee, N. J.

    2012-01-01

    Accessory root formation in primary teeth is an uncommon finding. An awareness and understanding of the presence of additional roots and unusual root canal morphology is essential as it determines the successful outcome of the endodontic treatment. This paper presents three case reports on the presence of three-rooted mandibular first primary molar (primary three-rooted mandibular left first molar and bilateral mandibular first molar). PMID:22629056

  2. Automatic Molar Extraction from Dental Panoramic Radiographs for Forensic Personal Identification

    NASA Astrophysics Data System (ADS)

    Samopa, Febriliyan; Asano, Akira; Taguchi, Akira

    Measurement of an individual molar provides rich information for forensic personal identification. We propose a computer-based system for extracting an individual molar from dental panoramic radiographs. A molar is obtained by extracting the region-of-interest, separating the maxilla and mandible, and extracting the boundaries between teeth. The proposed system is almost fully automatic; all that the user has to do is clicking three points on the boundary between the maxilla and the mandible.

  3. Age estimation using development of third molars in South Indian population: A radiological study

    PubMed Central

    Priyadharshini, K. Indra; Idiculla, Jose Joy; Sivapathasundaram, B.; Mohanbabu, V.; Augustine, Dominic; Patil, Shankargouda

    2015-01-01

    Aim: To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A–H) method of Demirjian et al. in Chennai population of South India. Materials and Methods: A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P < 0.05 was considered as the level of significance. Results: The results showed that the mean age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P < 0.05). Conclusion: There are differences indicating that maxillary and mandibular third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization. PMID:25984465

  4. Periodontal regeneration of transplanted rat molars after cryopreservation.

    PubMed

    Kawasaki, Naoko; Hamamoto, Yoshioki; Nakajima, Tamio; Irie, Kazuharu; Ozawa, Hidehiro

    2004-01-01

    The effects of cryopreservation on periodontal regeneration of transplanted rat molars were investigated histologically and histochemically in rats. Bilateral first and second maxillary molars of 4-week-old Wistar rats were gently extracted and transplanted into the abdominal subcutaneous connective tissue immediately or after cryopreservation in liquid nitrogen overnight. Donor teeth were slowly frozen by a rate-controlling freezer (program freezer) using 5% dimethylsulfoxide (DMSO) and 6% hydroxyethyl starch (HES) as cryoprotectants. One-four weeks after transplantation, they were carefully excised with the surrounding tissues. Regeneration of acellular cementum, periodontal ligament, and alveolar bone were observed 2 weeks after immediate transplantation. The pulp was repaired by the ingrowth of granulation tissue from the root apex followed by the formation of calcified tissue. The regenerated periodontal ligament was positive for alkaline phosphatase (ALP). Small or mononuclear tartrate resistant acid phosphatase (TRAP) positive cells were scattered on the newly formed alveolar bone and on the hard tissue in the pulp, but there was no external or internal progressive root resorption at 4 weeks. Cryopreserved teeth had acellular cementum with a rough surface at 1 week, but with the increase of cementoblasts and the appearance of periodontal ligament and alveolar bone, the surface became smooth at 3 weeks. Epithelial rests of Malassez (ERM) also revived. After regeneration of the periodontal tissues at 4 weeks, there was no evidence of root resorption. Although the process proceeded slowly, the cryopreserved teeth showed the periodontal regeneration substantially similar to that of the immediately transplanted teeth without progressive root resorption, indicating that they could be applicable for clinical use. PMID:14693198

  5. Brief communication: Molar development and crown areas in early Australopithecus.

    PubMed

    Lacruz, Rodrigo S; Ramirez Rozzi, Fernando V; Wood, Bernard A; Bromage, Timothy G

    2012-08-01

    Recent studies suggest that the hypodigms representing the two earliest Australopithecus (Au. anamensis and Au. afarensis) form an ancestor-descendant lineage. Understanding the details of this possible transition is important comparative evidence for assessing the likelihood of other examples of ancestor-descendant lineages within the hominin clade. To this end we have analyzed crown and cusp base areas of high resolution replicas of the mandibular molars of Au. anamensis (Allia Bay and Kanapoi sites) and those of Au. afarensis (Hadar, Laetoli, and Maka). We found no statistically significant differences in crown areas between these hypodigms although the mean of M(1) crowns was smaller in Au. anamensis, being the smallest of any Australopithecus species sampled to date. Intraspecies comparison of the areas of mesial cusps for each molar type using Wilcoxon signed rank test showed no differences for Au. anamensis. Significant differences were found between the protoconid and metaconid of Au. afarensis M(2)s and M(3)s. Furthermore, the area formed by the posterior cusps as a whole relative to the anterior cusps showed significant differences in Au. afarensis M(1)s and in Au. anamensis M(2)s but no differences were noted for M(3)s of either taxon. Developmental information derived from microstructural details in enamel shows that M(1) crown formation in Au. anamensis is similar to Pan and shorter than in H. sapiens. Taken together, these data suggests that the overall trend in the Au. anamensis-Au. afarensis transition may have involved a moderate increase in M(1) crown areas with relative expansion of distal cusps. PMID:22623291

  6. Saving the 2nd Molar from the 3rd Is it Really the Guilt of the Tilt?

    PubMed Central

    Yadav, Pankaj; Nawal, Ruchika Roongta; Talwar, Sangeeta; Verma, Mahesh

    2016-01-01

    Introduction Clinicians often relate the distal caries in second molars to angulated third molars, which if left undetected can lead to gross decay that may further require removal of the tooth. Due to this fact, many third molars are advised for prophylactic removal to prevent decay in the second molar. But this approach would only be justified when the incidence of decay/loss of second molar due to third molar are reasonably high. We sought to determine incidence of caries experience and also sequel extraction in second molars associated with the third molars. Aim The study was conducted to answer the basic question that whether the incidence of caries and subsequent extraction of second molar due to angulated third molars is high enough to justify the prophylactic removal of third molar or not. Materials and Methods This study was conducted on radiographic records of 1187 patients. The effect of tilted third molar on the second molar was measured in relation with three parameters namely level & position of third molar with respect to second molar and the distribution among arches. Results The results indicated that out of total number of teeth examined only 5.4% of maxillary and 9.6% of mandibular second molars were affected by tilted third molars. Further, only 2.2% of mandibular and 2.9% of maxillary second molars were indicated for extraction. The data was statistically insignificant. Conclusion It was concluded that distal caries in second molars is not very common. It may be present in some cases of third molar impactions and prophylactic removal of these impacted teeth may not be considered appropriate. PMID:27437353

  7. A Prospective Study of Clinical Outcomes Related to Third Molar Removal or Retention

    PubMed Central

    Cunha-Cruz, Joana; Rothen, Marilynn; Spiekerman, Charles; Drangsholt, Mark; Anderson, Loren; Roset, Gayle A.

    2014-01-01

    Objectives. We investigated outcomes of third molar removal or retention in adolescents and young adults. Methods. We recruited patients aged 16 to 22 years from a dental practice–based research network in the Pacific Northwest from May 2009 through September 2010 who had at least 1 third molar present and had never undergone third molar removal. Data were acquired via questionnaire and clinical examination at baseline, periodic online questionnaires, and clinical examination at 24 months. Results. A total of 801 patients participated. Among patients undergoing third molar removal, rates of paresthesia and jaw joint symptoms lasting more than 1 month were 6.3 and 34.3 per 100 person-years, respectively. Among patients not undergoing removal, corresponding rates were 0.7 and 8.8. Periodontal attachment loss at distal sites of second molars did not significantly differ by third molar removal status. Incident caries at the distal surfaces of second molars occurred in fewer than 1% of all sites. Conclusions. Rates of paresthesia and temporomandibular joint disorder were higher after third molar removal. Periodontal attachment loss and incident caries at the distal sites of second molars were not affected by extraction status. PMID:24524521

  8. 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

  9. Periodontal considerations in the use of bonds or bands on molars in adolescents and adults.

    PubMed

    Boyd, R L; Baumrind, S

    1992-01-01

    This longitudinal study compared the periodontal status of bonded and banded molars in 20 adult and 40 adolescent patients before, during and after treatment with fixed orthodontic appliances. Plaque accumulation (measured by the Plaque Index), gingival inflammation (measured by the Gingival Index and the bleeding tendency), and pocket depth were assessed by one examiner at sites along the mesio-buccal line angle of the maxillary right first molar and the mandibular left first molar. Assessments were made immediately prior to the placement of fixed appliances (pretreatment), at 1, 3, 6, 9, 12 and 18 months after appliances were placed; and 3 months after appliances were removed (posttreatment). Loss of attachment between the pretreatment and posttreatment visits also was determined. At pretreatment, no significant differences were found in gingival inflammation between maxillary and mandibular banded and bonded molars. During treatment, both maxillary and mandibular banded molars showed significantly (p less than 0.05) greater gingival inflammation and plaque accumulation than did bonded molars. Three months after appliance removal, the maxillary molars that had been banded continued to show significantly more gingival inflammation and loss of attachment than did the maxillary molars that had been bonded. When all banded and bonded teeth were grouped by patient age, mean values for plaque accumulation and gingival inflammation in the maxillary molar regions were significantly greater for adolescents than for adults. PMID:1626745

  10. Assessment of maxillary third molars with panoramic radiography and cone-beam computed tomography

    PubMed Central

    Jung, Yun-Hoa

    2015-01-01

    Purpose This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT). Materials and Methods A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Results Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Conclusion Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images. PMID:26730371

  11. Reduced radiation-absorbed dose to tissues with partial panoramic radiography for evaluation of third molars.

    PubMed

    Kircos, L T; Eakle, W S; Smith, R A

    1986-05-01

    The radiation-absorbed doses from panoramic radiography, distal molar radiography, and a partial panoramic radiographic technique that exposes only the third molar region to radiation are compared. Doses of radiation to the submandibular salivary gland were comparable by all three techniques, but doses of radiation to the head and neck were reduced greatly by the partial panoramic radiographic technique. Partial panoramic radiography is a diagnostically satisfactory and a radiologically safer technique for evaluation of third molar pathosis than is panoramic or distal molar radiography. PMID:3458783

  12. Reduced radiation-absorbed dose to tissues with partial panoramic radiography for evaluation of third molars

    SciTech Connect

    Kircos, L.T.; Eakle, W.S.; Smith, R.A.

    1986-05-01

    The radiation-absorbed doses from panoramic radiography, distal molar radiography, and a partial panoramic radiographic technique that exposes only the third molar region to radiation are compared. Doses of radiation to the submandibular salivary gland were comparable by all three techniques, but doses of radiation to the head and neck were reduced greatly by the partial panoramic radiographic technique. Partial panoramic radiography is a diagnostically satisfactory and a radiologically safer technique for evaluation of third molar pathosis than is panoramic or distal molar radiography.

  13. The influence of impaction to the third molar mineralization in northwestern Chinese population.

    PubMed

    Guo, Yu-cheng; Yan, Chun-xia; Lin, Xing-wei; Zhang, Wen-tao; Zhou, Hong; Pan, Feng; Wei, Lai; Tang, Zheng; Liang, Feng; Chen, Teng

    2014-07-01

    Age estimation by third molar mineralization has been developed for a period of time. Recent studies showed that impaction status has an influence on the rate of the third molar mineralization in Europids and male Black African populations. In this regard, the present study was conducted to determine whether the impaction status could delay the chronological process of third molar mineralization in northwestern Chinese population too. A total of 3,512 digital orthopantomograms of 1,255 male and 2,257 female northwestern Chinese subjects aged from 11 to 26 years were assessed based on the formation stages described by Demirjian et al. with two modifications. Mineralization stage and impaction status were determined for all third molars. Statistical measures were calculated at stages C-H in the male and female gender for both impacted and non-impacted third molars. It was ascertained that the mean ages with impacted third molars at stages C-H were 0.02-1.42 years higher in males and 0.04-1.52 years higher in females than those with non-impacted third molars, but statistical differences were only found at stages C, D, and E in males and stages D and E in females. The probabilities of being under 14, 16, or 18 years of age with non-impacted third molars were all higher than those with impacted third molars. The results prove that impacted third molars show significant slower mineralization than non-impacted ones at stages D and E in both males and females of northwestern Chinese population. It is recommended to consider the influence of impaction on the rate of third molar mineralization for dental age estimation. PMID:24532176

  14. Accuracy of Panoramic Radiograph in Assessment of the Relationship Between Mandibular Canal and Impacted Third Molars

    PubMed Central

    Tantanapornkul, Weeraya; Mavin, Darika; Prapaiphittayakun, Jaruthai; Phipatboonyarat, Natnicha; Julphantong, Wanchanok

    2016-01-01

    Background: The relationship between impacted mandibular third molar and mandibular canal is important for removal of this tooth. Panoramic radiography is one of the commonly used diagnostic tools for evaluating the relationship of these two structures. Objectives: To evaluate the accuracy of panoramic radiographic findings in predicting direct contact between mandibular canal and impacted third molars on 3D digital images, and to define panoramic criterion in predicting direct contact between the two structures. Methods: Two observers examined panoramic radiographs of 178 patients (256 impacted mandibular third molars). Panoramic findings of interruption of mandibular canal wall, isolated or with darkening of third molar root, diversion of mandibular canal and narrowing of third molar root were evaluated for 3D digital radiography. Direct contact between mandibular canal and impacted third molars on 3D digital images was then correlated with panoramic findings. Panoramic criterion was also defined in predicting direct contact between the two structures. Results: Panoramic findings of interruption of mandibular canal wall, isolated or with darkening of third molar root were statistically significantly correlated with direct contact between mandibular canal and impacted third molars on 3D digital images (p < 0.005), and were defined as panoramic criteria in predicting direct contact between the two structures. Conclusion: Interruption of mandibular canal wall, isolated or with darkening of third molar root observed on panoramic radiographs were effective in predicting direct contact between mandibular canal and impacted third molars on 3D digital images. Panoramic radiography is one of the efficient diagnostic tools for pre-operative assessment of impacted mandibular third molars. PMID:27398105

  15. Appearance of dentin gamma-carboxyglutamic acid-containing proteins in developing rat molars in vitro

    SciTech Connect

    Finkelman, R.D.; Butler, W.T.

    1985-07-01

    An in vitro model of mineralization was devised in order to study the developmental appearance of dentin gamma-carboxyglutamic acid-containing proteins (DGPs) in relation to the onset of mineralization. Maxillary third molars from 11-day-old rats were cultured with or without fetal calf serum (FCS) as modified from Navia et al. Molars were incubated without radiolabel, or with either /sup 45/CaCl/sub 2/ (5 microCi/ml) for 24 hr at various stages of a ten-day culture period or (/sup 3/H)-leucine (10 microCi/ml) for 24 hr at the eighth day of culture. Molars were lyophilized and extracted with 10% formic acid overnight at 4 degrees C. DGPs in extracts were detected by immunologic and chromatographic techniques; DGPs in molar sections were detected by immunolocalization using indirect immunofluorescence. Molar development was evaluated histologically using the Von Kossa staining technique. Molars cultured with FCS showed histologic evidence for mineralized dentin and enamel and a significant increase in /sup 45/Ca uptake after the sixth day in vitro. Eleven-day-old molars in vivo and molars cultured without FCS showed no evidence of the presence of mineralized tissues. (/sup 3/H)-Leucine-labeled DGPs were isolated and identified by affinity and reversed-phase high-performance liquid chromatography and by gel electrophoresis from both mineralized and unmineralized molars. DGP antigens were localized immunohistochemically using rabbit anti-rat antibodies raised against a highly purified DGP preparation. In the unmineralized molar, antigenicity was seen in odontoblasts but not in predentin matrix, preodontoblasts, or in any other cell type. Antigens in the mineralized molar were localized to odontoblasts and dentin.

  16. Modified Distal Shoe Appliance for Premature Loss of Multiple Deciduous Molars: A Case Report

    PubMed Central

    K., Navin H.; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

    2014-01-01

    Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist’s armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first permanent molar into place. Conventional design poses various limitations in cases of premature loss of multiple deciduous molars. Thus, it is required to modify the conventional designs according to the needs of the patient. This case report describes an innovative modification of distal shoe appliance in cases of premature loss of multiple deciduous molars. In the present case, modification of distal shoe space maintainer was advocated because of inadequate abutments caused due to multiple loss of deciduous molars. Bilateral design of distal shoe was planned for unilateral loss of deciduous molars. PMID:25302284

  17. Prenatal screening tests may be a warning for the partial molar pregnancy? case report

    PubMed Central

    Sargin, Mehmet Akif; Tug, Niyazi; Yassa, Murat; Yavuz, Arzu

    2015-01-01

    Prenatal screening tests are frequently requested for chromosomal abnormalities. Placental pathologies in early pregnancy may be overlooked, especially in partial molar pregnancy. We are reporting an incorrect preliminary diagnosed case with an increased risk of Down syndrome in her first-trimester screening test due to partial molar pregnancy. PMID:26175814

  18. Maxillary Tuberosity Fracture Associated with First Molar Extraction: A Case Report

    PubMed Central

    Polat, Hidayet B.; Ay, Sinan; Kara, M. Isa

    2007-01-01

    Maxillary tuberosity fractures during molar teeth extraction can occur commonly in dental practice; however, very few cases are reported and discussed in the literature. This article presents a case of large fracture of maxillary tuberosity during extraction of first maxillary molar tooth and its conservative treatment outcomes. PMID:19212477

  19. Concomitant Third Molar Removal During Sagittal Split Osteotomy of the Mandible.

    PubMed

    Sasaki, Ryo; Yao, Chuan-Fong; Chen, Ying-An; Lin, Cheng-Hui; Chen, Yu-Ray

    2016-01-01

    It is described in textbook about management of third molar in orthognathic surgery that "ideally, the third molars should be removed 9 to 12 months before sagittal split osteotomy (SSO)." At the Chang Gung Craniofacial Center, the authors always remove mandibular third molars during SSO, because: removal of third molars at the same time of SSO could reduce psychological stress on patients by saving 1 surgical procedure under local anesthesia, better exposure of impacted third molars could be facilitated by sagittal split of buccal cortical plate, rigid fixation could be performed without difficulty by our fixation method using plates and screws crossover anterior oblique line. Strong force during the elevation of third molars, however, may result in the fracture of distal segment of SSO, where the buccal cortical plate is relatively thin because of the presence of third molar. Therefore, more care needs to be taken in the surgical technique, which is different from ordinary tooth extraction. In this paper, the details of surgical procedure of third molar removal during SSO were reported. PMID:26745199

  20. Degradation of Ultra-High Molar Mass Polymers in Size-Exclusion Chromatography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The degradation of high molar mass polymers during size-exclusion chromatography (SEC) analysis has been a topic of interest for several decades. Should a polymer degrade during analysis, the accuracy of the molar mass (M) and architectural information obtained will be compromised. To this effect,...

  1. Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults.

    PubMed

    Karadayi, Beytullah; Kaya, Ahsen; Kolusayın, Melek Ozlem; Karadayi, Sükriye; Afsin, Hüseyin; Ozaslan, Abdi

    2012-11-01

    Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15-23 years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22 years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars' eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation. PMID:23010906

  2. Mandibular third molar development after mantle radiation in long-term survivors of childhood Hodgkin's disease.

    PubMed

    McGinnis, J P; Hopkins, K P; Thompson, E I; Hustu, H O

    1987-05-01

    Sequential panoramic radiographs were assessed for mandibular third molar development in 47 long-term survivors of childhood Hodgkin's disease after treatment with 37 Gy mantle field radiation. To make a comparison, panoramic radiographs of 149 healthy, nonirradiated children were reviewed for the presence of mandibular third molars. In children between the ages of 7 and 12 years, bilateral agenesis of mandibular third molars was more frequent in patients who had been treated with mantle radiation than in nonirradiated patients. Unilateral agenesis, crown hypoplasia, and root growth impairment of mandibular third molars were also found. Similar, apparent, radiation-induced developmental anomalies were noted in maxillary third molars of the irradiated patients. PMID:3473386

  3. A Noble, Easy and Conceptual Radiographic Analysis to Assess the Type of Tooth Movement (Molar Distalization)

    PubMed Central

    Prakash, Anaveri Thimmappa; Deepthi; Naik, Atri

    2015-01-01

    Context and Aim Bodily tooth movement is desirable in the field of Orthodontics and so is with molar distalization. Till date there is no such analysis available which could gauge and quantify the molar distalization and the type of tooth movement achieved, therefore one was required. Materials and Methods An OPG and Lateral cephalogram was used taking Inter orbitale plane and FH plane respectively as reference lines and the analysis was devised to measure the amount and type of tooth movement achieved in distalization of molar. Conclusion This analysis is a noble, easy and conceptual analysis to assess the type of tooth movement achieved during molar distalization and other molar movements using Lateral cephalogram and orthopantomogram. PMID:26436040

  4. Removal of an Upper Third Molar from the Maxillary Sinus

    PubMed Central

    Amorim, Klinger de Souza; da Silva, Vanessa Tavares; da Cunha, Rafael Soares; Souto, Maria Luisa Silveira; São Mateus, Carla Rocha; Souza, Liane Maciel de Almeida

    2015-01-01

    The maxillary sinus or antrum is the largest of the paranasal sinuses. It is located in the maxillary bone and has a proximity to the apexes of upper molars and premolars, which allows it to form a direct link between the sinus and the oral cavity. Dislocation of a foreign body or tooth to the interior of a paranasal sinus is a situation that can occur as a result of car accidents, firearm attacks, or iatrogenic in surgical procedures. Therefore, it is necessary to know how to treat this kind of situation. This study's objective is to report the case of a 23-year-old female patient, leucoderma, who sought treatment from the Surgical Unit at the Dental Faculty of the Federal University of Sergipe. She had a history of pain and edema in the right side of the genian region and two failed attempts at removing dental unit (DU) 18. The extraoral clinical exam revealed intense edema of the left hemiface with signs of infection, excoriation of the labial commissure, hematoma, a body temperature of 39°C, and a limited ability to open her mouth. The patient was medicated and treated surgically. The tooth was removed from the maxillary sinus with caution, as should have been done initially. PMID:25705524

  5. Variability of Australopithecus second maxillary molars from Sterkfontein Member 4.

    PubMed

    Fornai, Cinzia; Bookstein, Fred L; Weber, Gerhard W

    2015-08-01

    The question of how many Australopithecus species lived at Sterkfontein Member 4 and Makapansgat continues to be controversial inasmuch as the fossils are poorly preserved, the stratigraphy is difficult to interpret, and the cranial, dental, and postcranial remains are mostly not associated. To proceed we applied the most intensive modern methods of 3D geometric morphometrics to dental form, specifically the shapes of the upper second molars (M(2)s) in a sample combining 13 Australopithecus, 11 Paranthropus, and 23 Homo. We analyzed outer and inner crown surfaces, as well as crown and cervical outlines both separately and together, using a total of 16 landmarks, 51 curve semilandmarks, and 48 pseudolandmarks over the four structures. Outer and inner enamel surfaces are highly correlated in this dataset, while crown outline is the least informative of the four structures. Homo was easily distinguished from both Australopithecus and Paranthropus by these methods, likewise Homo sapiens from Homo neanderthalensis. There were, however, no stable classes within the Australopithecus sample or between Australopithecus and Paranthropus. Instead, there was a gradient along which Australopithecus prometheus and Australopithecus africanus lie toward the extremes, with Paranthropus overlapping both. If there are indeed different species at this site, then either their M(2) morphologies are uninformative or else the present sample is too small to make an accurate assessment. Our findings suggest that the variability of the Australopithecus specimens will be difficult to interpret authoritatively, independent of the method used. PMID:26163295

  6. Biodentine Pulpotomy in Mature Permanent Molar: A Case Report

    PubMed Central

    2016-01-01

    Irreversible pulpitis is the most common reason for endodontic treatment in primary and permanent teeth. Root canal therapy and extraction are the two viable and most documented treatment options for the same. Studies with regards to management of mature permanent teeth with carious exposure and treatment with vital pulp therapies such as adult permanent tooth pulpotomy are scarce. However, permanent tooth pulpotomy with the new calcium-silicate based cements (Mineral Trioxide Aggregate and Biodentine) can help preserve the tooth pulp vitality and promote healing and repair foregoing the more invasive root canal therapy procedure. A 12-year old male patient with irreversible pulpitis in right mandibular first permanent molar was treated with complete coronal pulpotomy with placement of Biodentine in the pulp chamber and a full coronal coverage using stainless steel crown. Clinical and radiographic examinations were performed at three, six, twelve and eighteen months. At the end of 18 months, the patient was completely asymptomatic and the tooth was free of any clinical and radiographic signs of inflammation and infection.

  7. Molar crown inner structural organization in Javanese Homo erectus.

    PubMed

    Zanolli, Clément

    2015-01-01

    This contribution investigates the inner organizational pattern (tooth tissue proportions and enamel-dentine junction morphology) of seven Homo erectus permanent molar crowns from the late Lower-early Middle Pleistocene Kabuh Formation of the Sangiran Dome (Central Java, Indonesia). The previous study of their external characteristics confirmed the degree of time-related structural reduction occurred in Javanese H. erectus, and also revealed a combination of nonmetric features which are rare in the Lower and early Middle Pleistocene dental record, but more frequently found in recent humans. In accordance with their outer occlusal morphology, the specimens exhibit a set of derived internal features, such as thick to hyperthick enamel, an incomplete expression of the crest patterns at the enamel-dentine junction (EDJ) level, a sharp EDJ topography. As a whole, these features differ from those expressed in some penecontemporaneous specimens/samples representing African H. erectus/ergaster and H. heidelbergensis, as well as in Neanderthals, but occur in recent human populations. Further research in virtual dental paleoanthropology to be developed at macroregional scale would clarify the polarity and intensity of the intermittent exchanges between continental and insular Southeast Asia around the Lower to Middle Pleistocene boundary, as well as should shed light on the still poorly understood longitudinal evolutionary dynamics across continental Asia. PMID:25209431

  8. Functional implication of nucleolin in the mouse first molar development.

    PubMed

    Xie, Ming; Kobayashi, Ieyoshi; Kiyoshima, Tamotsu; Yamaza, Haruyoshi; Honda, Jun-ya; Takahashi, Keiko; Enoki, Norio; Akamine, Akifumi; Sakai, Hidetaka

    2007-08-10

    We examined the functional implication of nucleolin in the mouse first molar development. Both the nucleolin mRNA and protein expressions were demonstrated in the odontogenic epithelial cells in the early stage and in the inner enamel epithelial layer in the late stage. The expression pattern of nucleolin corresponded to the proliferating cells in the tooth germ, thus showing that nucleolin could possibly be related to cell proliferation. No in situ signal of nucleolin was found in the primary enamel knot (PEK). Furthermore, nucleolin protein was demonstrated in the PEK by immunohistochemistry. The existence of nucleolin protein in the PEK may possibly be related to the apoptosis in the PEK cells. An inhibition assay using the hemagglutinating virus of Japan-liposome containing nucleolin antisense phosphorothioated oligonucleotide (AS S-ODN) in cultured mouse mandibles at embryonic day (E) 11.0 showed a marked growth inhibition of tooth germ. Moreover, no developmental arrest was found in the cultured tooth germ at E15.0 treated with nucleolin AS S-ODN. Real time PCR was performed to examine the mRNA expression of nucleolin-related genes, and a significant reduction in the midkine mRNA expression was thus observed in the mouse mandible after being treated with nucleolin AS S-ODN. This inhibition assay indicated that nucleolin could thus be involved in the early stage of tooth germ initiation and morphogenesis, possibly by regulating the midkine expression. PMID:17562718

  9. Dietary Inference from Upper and Lower Molar Morphology in Platyrrhine Primates

    PubMed Central

    Allen, Kari L.; Cooke, Siobhán B.; Gonzales, Lauren A.; Kay, Richard F.

    2015-01-01

    The correlation between diet and dental topography is of importance to paleontologists seeking to diagnose ecological adaptations in extinct taxa. Although the subject is well represented in the literature, few studies directly compare methods or evaluate dietary signals conveyed by both upper and lower molars. Here, we address this gap in our knowledge by comparing the efficacy of three measures of functional morphology for classifying an ecologically diverse sample of thirteen medium- to large-bodied platyrrhines by diet category (e.g., folivore, frugivore, hard object feeder). We used Shearing Quotient (SQ), an index derived from linear measurements of molar cutting edges and two indices of crown surface topography, Occlusal Relief (OR) and Relief Index (RFI). Using SQ, OR, and RFI, individuals were then classified by dietary category using Discriminate Function Analysis. Both upper and lower molar variables produce high classification rates in assigning individuals to diet categories, but lower molars are consistently more successful. SQs yield the highest classification rates. RFI and OR generally perform above chance. Upper molar RFI has a success rate below the level of chance. Adding molar length enhances the discriminatory power for all variables. We conclude that upper molar SQs are useful for dietary reconstruction, especially when combined with body size information. Additionally, we find that among our sample of platyrrhines, SQ remains the strongest predictor of diet, while RFI is less useful at signaling dietary differences in absence of body size information. The study demonstrates new ways for inferring the diets of extinct platyrrhine primates when both upper and lower molars are available, or, for taxa known only from upper molars. The techniques are useful in reconstructing diet in stem representatives of anthropoid clade, who share key aspects of molar morphology with extant platyrrhines. PMID:25738266

  10. Dietary inference from upper and lower molar morphology in platyrrhine primates.

    PubMed

    Allen, Kari L; Cooke, Siobhán B; Gonzales, Lauren A; Kay, Richard F

    2015-01-01

    The correlation between diet and dental topography is of importance to paleontologists seeking to diagnose ecological adaptations in extinct taxa. Although the subject is well represented in the literature, few studies directly compare methods or evaluate dietary signals conveyed by both upper and lower molars. Here, we address this gap in our knowledge by comparing the efficacy of three measures of functional morphology for classifying an ecologically diverse sample of thirteen medium- to large-bodied platyrrhines by diet category (e.g., folivore, frugivore, hard object feeder). We used Shearing Quotient (SQ), an index derived from linear measurements of molar cutting edges and two indices of crown surface topography, Occlusal Relief (OR) and Relief Index (RFI). Using SQ, OR, and RFI, individuals were then classified by dietary category using Discriminate Function Analysis. Both upper and lower molar variables produce high classification rates in assigning individuals to diet categories, but lower molars are consistently more successful. SQs yield the highest classification rates. RFI and OR generally perform above chance. Upper molar RFI has a success rate below the level of chance. Adding molar length enhances the discriminatory power for all variables. We conclude that upper molar SQs are useful for dietary reconstruction, especially when combined with body size information. Additionally, we find that among our sample of platyrrhines, SQ remains the strongest predictor of diet, while RFI is less useful at signaling dietary differences in absence of body size information. The study demonstrates new ways for inferring the diets of extinct platyrrhine primates when both upper and lower molars are available, or, for taxa known only from upper molars. The techniques are useful in reconstructing diet in stem representatives of anthropoid clade, who share key aspects of molar morphology with extant platyrrhines. PMID:25738266

  11. Comparison of Primary Molar Crown Dimensions with Stainless Steel Crowns in a Sample of Iranian Children

    PubMed Central

    Afshar, Hossein; Kamali Sabeti, Arghavan; Shahrabi, Mahdi

    2015-01-01

    Background and aims. Due to anatomic variation in tooth anatomy between populations, this study compared the buccolingual (BL) and mesiodistal (MD) dimensions of primary molars with those of stainless steel crowns (SSCs) in anIranian population. Materials and methods. Impressions were taken from both dental arches of children, and casts were poured. Teeth with caries, restoration, hypoplasia or other dental anomalies were excluded. 216 primary molars were selected and divided into 4 groups of 54 each (maxillary and mandibular first and second primary molars). MD/BL dimensions were measured using a digital caliper with 0.01 mm precision on casts and SCCs (3M brand). Data were assessed using paired t-test, post hoc test and ANOVA. P < 0.05 was considered statistically significant. Results. The MD dimension of the lower first molar SSC and the BL dimension of the lower second molar SSC had the least difference with the corresponding values of the respective teeth. The MD dimension of the upper second molar SSC and the BL dimension of the upper first molar SSC had the greatest difference with the corresponding values in the respective teeth. Comparison of the two different brands of SSCs for the upper first molar revealed that both types had significant differences with the teeth in terms of both MD (P = 0.0) and BL (P = 0.0) dimensions. Conclusion. In the studied population, best adaptation was seen in second lower molars and the least adaptationswere seen in first and second upper molars. PMID:26236433

  12. Characterization of stem and progenitor cells in the dental pulp of erupted and unerupted murine molars

    PubMed Central

    Balic, Anamaria; Aguila, H. Leonardo; Caimano, Melissa J.; Francone, Victor P.; Mina, Mina

    2010-01-01

    In the past few years there have been significant advances in the identification of putative stem cells also referred to as “mesenchymal stem cells” (MSC) in dental tissues including the dental pulp. It is thought that MSC in dental pulp share certain similarities with MSC isolated from other tissues. However, cells in dental pulp are still poorly characterized. This study focused on the characterization of progenitor and stem cells in dental pulps of erupted and unerupted mice molars. Our study showed that dental pulps from unerupted molars contain a significant number of cells expressing CD90+/CD45-, CD117+/CD45-, Sca-1+/CD45- and little if any CD45+ cells. Our in vitro functional studies showed that dental pulp cells from unerupted molars displayed extensive osteo-dentinogenic potential but were unable to differentiate into chondrocytes and adipocytes. Dental pulp from erupted molars displayed a reduced number of cells, contained higher percentage of CD45+ and lower percentage of cells expressing CD90+/CD45-, CD117+/CD45- as compared to unerupted molars. In vitro functional assays demonstrated the ability of a small fraction of cells to differentiate into odontoblasts, osteoblasts, adipocytes and chondrocytes. There was a significant reduction in the osteo-dentinogenic potential of the pulp cells derived from erupted molars compared to unerupted molars. Furthermore, the adipogenic and chondrogenic differentiation of pulp cells from erupted molars was dependent on a long induction period and infrequent. Based on these findings we propose that the dental pulp of the erupted molars contain a small population of multipotent cells, whereas the dental pulp of the unerupted molars does not contain multipotent cells but is enriched in osteo-dentinogenic progenitors engaged in the formation of coronal and radicular odontoblasts. PMID:20193787

  13. Complex cellular responses to tooth wear in rodent molar.

    PubMed

    Mahdee, A; Alhelal, A; Eastham, J; Whitworth, J; Gillespie, J I

    2016-01-01

    The arrangement and roles of the odontoblast and its process in sensing and responding to injuries such as tooth wear are incompletely understood. Evidence is presented that dentine exposure by tooth wear triggers structural and functional changes that aim to maintain tooth integrity. Mandibular first molars from freshly culled 8 week Wistar rats were prepared for light microscopy ground-sections (n=6), or fixed in 4% paraformaldehyde, decalcified in 17% EDTA, sectioned and stained with antibodies to cyto-skeletal proteins (vimentin (vim), α-tubulin (tub) and α-actin), cellular homeostatic elements (sodium potassium ATPase (NaK-ATPase) and sodium hydrogen exchanger (NHE-1)), and sensory nerve fibres (CGRP) (n=10) for fluorescence microscopy of worn and unworn regions of the mesial cusp. Immunoreactivity (IR) to vim, actin, NaK-ATPase and CGRP was confined to the pulpal third of odontoblast processes (OPs). IR to tub and nhe-1 was expressed by OPs in full dentine thickness. In areas associated with dentine exposure, the tubules contained no OPs. In regions with intact dentine, odontoblasts were arranged in a single cell layer and easily distinguished from the sub-odontoblast cells. In regions with open tubules, the odontoblasts were in stratified or pseudo-stratified in arrangement. Differences in structural antibody expression suggest a previously unreported heterogeneity of the odontoblast population and variations in different regions of the OP. This combined with differences in OPs extension and pulp cellular arrangement in worn and unworn regions suggests active and dynamic cellular responses to the opening of dentinal tubules by tooth wear. PMID:26547699

  14. Morphometric variation of extant platyrrhine molars: taxonomic implications for fossil platyrrhines.

    PubMed

    Nova Delgado, Mónica; Galbany, Jordi; Pérez-Pérez, Alejandro

    2016-01-01

    The phylogenetic position of many fossil platyrrhines with respect to extant ones is not yet clear. Two main hypotheses have been proposed: the layered or successive radiations hypothesis suggests that Patagonian fossils are Middle Miocene stem platyrrhines lacking modern descendants, whereas the long lineage hypothesis argues for an evolutionary continuity of all fossil platyrrhines with the extant ones. Our geometric morphometric analysis of a 15 landmark-based configuration of platyrrhines' first and second lower molars suggest that morphological stasis may explain the reduced molar shape variation observed. Platyrrhine lower molar shape might be a primitive retention of the ancestral state affected by strong ecological constraints throughout the radiation of the main platyrrhine families. The Patagonian fossil specimens showed two distinct morphological patterns of lower molars, Callicebus-like and Saguinus-like, which might be the precursors of the extant forms, whereas the Middle Miocene specimens, though showing morphological resemblances with the Patagonian fossils, also displayed new, derived molar patterns, Alouatta-like and Pitheciinae-like, thereby suggesting that despite the overall morphological stasis of molars, phenotypic diversification of molar shape was already settled during the Middle Miocene. PMID:27190704

  15. Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars

    PubMed Central

    Abarca, J.; Zaror, C.; Monardes, H.; Hermosilla, V.; Muñoz, C.; Cantin, M.

    2015-01-01

    SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully. PMID:25937698

  16. Incidence of chronic neuropathic pain subsequent to surgical removal of impacted third molars.

    PubMed

    Berge, Trond Inge

    2002-03-01

    To determine the incidence of atypical odontalgia/chronic neuropathic pain subsequent to surgical removal of impacted third molars, a telephone survey and a clinical investigation were carried out. Patients operated on for impacted mandibular third molars during 1994 96 in the Oral Surgery Clinic. School of Dentistry, University of Bergen, Bergen, Norway, were contacted by telephone. Answers were obtained from 1035 (71%) out of a total of 1458 operated patients. Median observation time was 5 years 9 months, ranging from 4 years 5 months to 6 years 9 months. All except 23 (2.2%) patients stated that they had no long-term symptoms or problems from the surgical site, jaw, or face after the third molar removal. These 23 patients were all examined clinically and radiologically, and symptoms and findings were evaluated. Seventeen patients had TMJ dysfunction: primarily pain of muscular and joint origin. Three patients had a periodontal problem associated with the adjacent second molar, with deep bony pockets and recurrent periodontal infection while two had chronic pulpitis of a second molar. One patient reported a temporary maxillary pain after removal of an ipsilateral mandibular third molar. None of the patients met the criteria for a diagnosis of atypical odontalgia/neuropathic pain. A 95% confidence interval of 0-0.38% of incidence rate of postoperative neuropathic pain was calculated. It is concluded that atypical odontalgia/ chronic neuropathic pain subsequent to surgical third molar removal is rare. PMID:12020113

  17. Morphometric variation of extant platyrrhine molars: taxonomic implications for fossil platyrrhines

    PubMed Central

    Nova Delgado, Mónica; Galbany, Jordi

    2016-01-01

    The phylogenetic position of many fossil platyrrhines with respect to extant ones is not yet clear. Two main hypotheses have been proposed: the layered or successive radiations hypothesis suggests that Patagonian fossils are Middle Miocene stem platyrrhines lacking modern descendants, whereas the long lineage hypothesis argues for an evolutionary continuity of all fossil platyrrhines with the extant ones. Our geometric morphometric analysis of a 15 landmark-based configuration of platyrrhines’ first and second lower molars suggest that morphological stasis may explain the reduced molar shape variation observed. Platyrrhine lower molar shape might be a primitive retention of the ancestral state affected by strong ecological constraints throughout the radiation of the main platyrrhine families. The Patagonian fossil specimens showed two distinct morphological patterns of lower molars, Callicebus—like and Saguinus—like, which might be the precursors of the extant forms, whereas the Middle Miocene specimens, though showing morphological resemblances with the Patagonian fossils, also displayed new, derived molar patterns, Alouatta—like and Pitheciinae—like, thereby suggesting that despite the overall morphological stasis of molars, phenotypic diversification of molar shape was already settled during the Middle Miocene. PMID:27190704

  18. The influence of endodontic infection on periodontal status in mandibular molars.

    PubMed

    Jansson, L E; Ehnevid, H

    1998-12-01

    The purpose of the study was to investigate the influence of an endodontic infection on periodontal probing depth and presence of furcation involvement in periodontally-involved mandibular molars. All first and second mandibular molars in 100 patients were selected if at least one was root-filled or had a possible periapical radiolucency. The sample consisted of patients from a referral population at a periodontal clinic which represented an adult population with a mean age between 50 and 60 years. For mandibular molars with periapical destruction at both roots, mean periodontal probing depth was significantly greater compared to teeth without periapical destruction. Horizontal furcation depths > or =3 mm were significantly more frequent at mandibular molars with periapical destruction. It is suggested that a root canal infection in periodontitis-involved molars may potentiate periodontitis progression by spreading of endodontic pathogens through patent accessory canals and dentinal tubules. In conclusion, an endodontic infection in mandibular molars was found to be associated with additional attachment loss in the furcation area, and may thus be considered to be one of several risk factors influencing the prognosis of molars in periodontitis-prone patients. PMID:9926769

  19. Developmental constraints revealed by co-variation within and among molar rows in two murine rodents.

    PubMed

    Renaud, Sabrina; Pantalacci, Sophie; Quéré, Jean-Pierre; Laudet, Vincent; Auffray, Jean-Christophe

    2009-01-01

    Morphological integration corresponds to interdependency between characters that can arise from several causes. Proximal causes of integration include that different phenotypic features may share common genetic sets and/or interact during their development. Ultimate causes may be the prolonged effect of selection favoring integration of functionally interacting characters, achieved by the molding of these proximal causes. Strong and direct interactions among successive teeth of a molar row are predicted by genetic and developmental evidences. Functional constraints related to occlusion, however, should have selected more strongly for a morphological integration of occluding teeth and a corresponding evolution of the underlying developmental and genetic pathways. To investigate how these predictions match the patterns of phenotypic integration, we studied the co-variation among the six molars of the murine molar row, focusing on two populations of house mice (Mus musculus domesticus) and wood mice (Apodemus sylvaticus). The size and shape of the three upper and lower molars were quantified and compared. Our results evidenced similar patterns in both species, size being more integrated than shape among all the teeth, and both size and shape co-varying strongly between adjacent teeth, but also between occluding teeth. Strong co-variation within each molar row is in agreement with developmental models showing a cascade influence of the first molar on the subsequent molars. In contrast, the strong co-variation between molars of the occluding tooth rows confirms that functional constraints molded patterns of integration and probably the underlying developmental pathways despite the low level of direct developmental interactions occurring among molar rows. These patterns of co-variation are furthermore conserved between the house mouse and the wood mouse that diverged >10 Ma, suggesting that they may constitute long-running constraints to the diversification of the murine

  20. Allometric and metameric shape variation in Pan mandibular molars: a digital morphometric analysis.

    PubMed

    Singleton, Michelle; Rosenberger, Alfred L; Robinson, Chris; O'neill, Rob

    2011-02-01

    The predominance of molar teeth in fossil hominin assemblages makes the patterning of molar shape variation a topic of bioanthropological interest. Extant models are the principal basis for understanding dental variation in the fossil record. As the sister taxon to the hominin clade, Pan is one such model and the only widely accepted extant hominid model for both interspecific and intraspecific variation. To explore the contributions of allometric scaling and meristic variation to molar variation in Pan, we applied geometric shape analysis to 3D landmarks collected from virtual replicas of chimpanzee and bonobo mandibular molars. Multivariate statistical analysis and 3D visualization of metameric and allometric shape vectors were used to characterize shape differences and test the hypothesis that species of Pan share patterns of metameric variation and molar shape allometry. Procrustes-based shape variables were found to effectively characterize crown shape, sorting molars into species and tooth-row positions with ≥ 95% accuracy. Chimpanzees and bonobos share a common pattern of M(1) -M(2) metameric variation, which is defined by differences in the relative position of the metaconid, size of the hypoconulid, curvature of the buccal wall, and proportions of the basins and foveae. Allometric scaling of molar shape is homogeneous for M(1) and M(2) within species, but bonobo and chimpanzee allometric vectors are significantly different. Nevertheless, the common allometric shape trend explains most molar-shape differences between P. paniscus and P. troglodytes. When allometric effects are factored out, chimpanzee and bonobo molars are not morphometrically distinguishable. Implications for hominid taxonomy and dietary reconstruction are discussed. PMID:21235007

  1. Rat molar teeth as a study model for direct pulp capping research in dentistry.

    PubMed

    Dammaschke, Till

    2010-01-01

    The aim of this review is to evaluate the suitability of rat molar teeth in preclinical evaluation of medical devices for direct pulp capping. The ISO standard 7405 states clearly that only non-rodent mammals are suitable species for animal research in dentistry. Furthermore, without clear justification a considerable number of researchers previously rejected results of animal experiments concerning preclinical evaluation of the biocompatibility of dental materials undertaken in rat molar teeth. However, in the past 50 years about 70 studies have been published using rat molar teeth in order to evaluate direct pulp capping, pulpotomies and tissue reactions after pulp exposure. Numerous studies showed that the healing of rat molar pulp tissue after direct pulp capping is histologically comparable with humans and other animal species pulp tissue. Rat molar teeth, including pulp tissue, can be seen anatomically, histologically, biologically, and physiologically as miniature human molar teeth. Hence, the essential biological reactions of the pulp tissue and the interaction during the different stages of wound healing of rat molar teeth are comparable with that of other mammals. Rat molar teeth are a valid study model in order to provide valuable data concerning pulp tissue reaction after direct pulp capping and related questions in dentistry. Therefore, the use of rats may significantly reduce the number of currently used higher animals in research. Tests in higher developed animals should be limited to experiments which clarify inconsistent results. However, some technical difficulties, like the small size of rat molar teeth must be dealt with before undertaking any research. PMID:19854755

  2. Vital Pulp Therapy with Three Different Pulpotomy Agents in Immature Molars: A Case Report

    PubMed Central

    Harandi, Azadeh; Forghani, Maryam; Ghoddusi, Jamileh

    2013-01-01

    Introduction This case report describes apexogenesis treatment of three molar teeth of an 8-year-old boy using three different pulpotomy agents. Methods Pulpotomy was performed on decayed immature molar teeth with established irreversible pulpitis and the remaining pulp was capped with either zinc oxide eugenol, ProRoot mineral trioxide aggregate or calcium-enriched mixture (CEM) cement. Teeth were restored with stainless steel crowns. Results Eighteen months clinical and radiographic follow-up revealed successful preservation of pulpal vitality with continued root development in all treated teeth. Conclusion Based on this case report, CEM cement may be an alternative option for pulpotomy treatment of immature permanent molars. PMID:23922578

  3. A New Orthodontic Appliance with a Mini Screw for Upper Molar Distalization

    PubMed Central

    2016-01-01

    The aim of this study is to present a new upper molar distalization appliance called Cise distalizer designed as intraoral device supported with orthodontic mini screw for upper permanent molar distalization. The new appliance consists of eight main components. In order to understand the optimum force level, the appliance under static loading is tested by using strain gage measurement techniques. Results show that one of the open coils produces approximately 300 gr distalization force. Cise distalizer can provide totally 600 gr distalization force. This range of force level is enough for distalization of upper first and second molar teeth. PMID:27528796

  4. [Analysis of divergent angle and length of CEJ to furcation entrance in extracted molars].

    PubMed

    Hou, G L; Chen, S F; Tsai, C C; Huang, J S

    1997-12-01

    The purposes of this study were to investigate the furcation entrance angle (FEA) and the distance between cemento-enamel junction (CEJ) and furcation entrance (FE) of the extracted maxillary and mandibular molars. Assay teeth comprised 89 maxillary molars and 93 mandibular molars. All the FEAs and CEJ-FEs of the molars were measured by a stereomicroscope at 2.5 x equipped with a Bioscan OPTIMAS Image Analyzer (BOIA). The results were summarized as follows: (1) The mean FEAs in the buccal, mesial and distal furcations were 96.3 +/- 10.0, 103.8 +/- 9.7, and 107.2 +/- 12.2 degrees in the maxillary molars, and 91.6 +/- 11.7, 101.7 +/- 11.5, and 97.1 +/- 10.7 degrees in the maxillary second molars, respectively. At the buccal and lingual furcations of mandibular first and second molars, they measured 100.5 +/- 9.7/102.7 +/- 8.5, and 93.3 +/- 11.5/91.7 +/- 10.8 degrees, respectively. (2) The mean distance of CEJ-FEs at the buccal, mesial and distal furcations of maxillary molars were 3.42 +/- 1.5mm, 3.55 +/- 0.97 mm, and 3.69 +/- 0.98mm for the first molars, and 3.01 +/- 1.04mm, 4.04 +/- 1.58mm and 3.00 +/- 1.14mm for the second molars. At the buccal and lingual furcations of the mandibular first and second molars, they were recorded as 1.90 +/- 0.08mm and 2.90 +/- 0.07mm, and 2.82 +/- 1.34mm and 3.46 +/- 1.03mm, respectively. It was concluded that buccal FEA of maxillary 2nd molar was the smallest (91.56 +/- 9.68 degrees) as compared to the mesial and distal FEAs; whereas the mean distance of CEJ-FEs at the buccal surface was the smallest (1.90mm +/- 0.08mm) when compared to the others. PMID:9436343

  5. Endodontic management of maxillary first molar with type I canal configuration- a rare case report.

    PubMed

    Desai, Niranjan; Jadhav, Ganesh Ranganath; Raghavendra, Srinidhi Surya; Mittal, Priya; Patil, Gururaj

    2015-04-01

    Thorough knowledge about the root canal variations is essential for the predictable endodontic treatment outcome. The root and root canal anatomy of maxillary first molar varies greatly. A Pub-med literature search about single rooted single canalled maxillary first molar was done to know its details such as incidence, diagnostic method used, age, sex and ethnic background of patient. This article presented report of a single rooted single canalled maxillary first molar in a 27-year-old healthy Asian female. PMID:26023655

  6. Paediatric dentistry in the new millennium: 4. Cost-effective restorative techniques for primary molars.

    PubMed

    Duggal, M S; Gautam, S K; Nichol, R; Robertson, A J

    2003-10-01

    In the fourth article in this series the techniques for carrying out pulp therapy and stainless steel restoration in primary molars are discussed. Early pulp involvement in primary molars means that pulp therapy and the use of appropriate coronal restoration, such as stainless steel crowns, are indispensable if repetitive restoration of primary molars is to be avoided. These techniques themselves are not difficult to carry out once the child's co-operation is established and should be well within the capability of any dentist with an interest in the dental care of children. PMID:14619729

  7. Accidental Displacement of Third Molar into the Sublingual Space: a Case Report

    PubMed Central

    Garcia, Robson Rodrigues; Botelho, Tessa Lucena; Franco, Ademir; Silva, Rhonan Ferreira

    2014-01-01

    ABSTRACT Background Successful extraction of third molars depends on preoperative diagnosis and planning. Gold standard preoperative examinations are performed through computed tomography, decreasing risks and avoiding potential accidents. The present report highlights the value of preoperative examinations in face of accidentally displaced third molars. Methods An 18-years-old female patient underwent a third mandibular molar extraction with a general dentist. Accidentally, the mandibular left third molar was displaced into the sublingual space, making necessary a second surgical step. The surgery was interrupted and the patient was referred to an expert in maxillofacial surgery. Results After 21 days awaiting an asymptomatic health status, the second surgical step was successfully performed using multislice computed tomography as preoperative imaging guide. Conclusions The present case report highlights the clinical usefulness of imaging planning and informed consents in face of legal and ethic potential complaints. PMID:25386232

  8. Management of Chronic Hyperplastic Pulpitis in Mandibular Molars of Middle Aged Adults- A Multidisciplinary Approach

    PubMed Central

    Lingeswaran, Somiya; Ari, Geetha; Thyagarajan, Ramakrishnan; Logaranjani, Anitha

    2016-01-01

    The molar tooth of children and young adults is a common site for chronic hyperplastic pulpitis (pulp polyp). It rarely occurs in middle aged adults. This condition is usually characterized by extensive involvement of the pulp, dictating the extraction of involved tooth. Extraction of permanent molars can lead to transient or permanent malocclusion, aesthetic, phonetic and functional problems. Here we report a case of pulp polyp in mandibular first molar of a 33-year-old woman that grew into the carious cavity. The aim of this case report is to describe the diagnosis of a chronic hyperplastic pulpitis involving the permanent molar as well as to describe its management in order to preserve them as a functional unit of the dentition. PMID:26894192

  9. Root Canal Configuration of Maxillary First Permanent Molars in an Iranian Population

    PubMed Central

    Shahi, Shahriar; Yavari, Hamid Reza; Rahimi, Saeed; Ahmadi, Ali

    2007-01-01

    Background and aims It is critical to have a proper knowledge of the normal anatomy of the pulp and its variations for the success of endodontic treatment. The purpose of this study was to investigate variations in the root canal system of maxillary first permanent molars in an Iranian population. Materials and methods In this study, 137 maxillary first molars were decalcified, dye-injected, cleared and studied. Results The results demonstrated that 37.96% of the maxillary first molars under study had three canals, 58.4% had four canals and 3.64% had five canals. Conclusion According to the results of this study and considering variations in the root canal systems of maxillary first molars, it seems that great care should be taken in the root canal treatment of these teeth. PMID:23277826

  10. Root Canal Morphology of Human Mandibular First Permanent Molars in an Iranian Population

    PubMed Central

    Shahi, Shahriar; Yavari, Hamid Reza; Rahimi, Saeed; Torkamani, Reza

    2008-01-01

    Background and aims The knowledge of variations in root canal morphology is critical for a successful endodontic treatment. The purpose of this study was to investigate variations in the root canal system of human mandibular first permanent molars in an Iranian population. Materials and methods In this study, 209 mandibular first molar teeth were decalcified, dye-injected, and cleared in order to determine the number and configuration of the root canals. Results The results demonstrated that 65.56% of the mandibular first molars under study had three, 31.57% had four and 2.87% had two canals. Conclusion According to the results of this study and considering variations in the root canal systems of the mandibular first molars, it seems that great care should be taken in the root canal treatment of these teeth. PMID:23285325

  11. Molar incisor hypomineralization: considerations about treatment in a controlled longitudinal case.

    PubMed

    de Oliveira, Daniela Cristina; Favretto, Carla Oliveira; Cunha, Robson Frederico

    2015-01-01

    Molar incisor hypomineralization (MIH) is a defect in the tooth enamel of systemic origin and may affect one or all four first permanent molars frequently associated with the permanent incisors. This case reports a 7-year-old child with severe MIH in the permanent molars associated with tooth decay and intense pain. In the first stage of treatment, therapy was performed with fluoride varnish and restoration with glass ionomer cement (GIC). After 6 years of clinical and radiographic follow-up, the restorations presented wear and fractures on the margins, indicating their replacement with composite resin. Severe cases of MIH in the early permanent molars can be treated with varnish and GIC to restore the patient's comfort and strengthen the hypomineralized dental structures. The clinical and radiographic monitoring frequently indicated when the restoration with composite resin should be performed. PMID:25872636

  12. How Many Digits Should We Use in Formula or Molar Mass Calculations?

    ERIC Educational Resources Information Center

    Svensson, Christer

    2004-01-01

    The calculations of uncertainties in the formula or molar masses of compounds are streamlined. Three rules of increasing complexity are proposed, which overestimate the uncertainty so there is little if any risk that the true values are missed.

  13. The effect of cellulose molar mass on the properties of palmitate esters.

    PubMed

    Willberg-Keyriläinen, Pia; Talja, Riku; Asikainen, Sari; Harlin, Ali; Ropponen, Jarmo

    2016-10-20

    Nowadays one of the growing trends is to replace oil-based products with cellulose-based materials. Currently most cellulose esters require a huge excess of chemicals and have therefore, not been broadly used in the industry. Here, we show that decreasing the molar mass of cellulose by ozone hydrolysis provides cellulose functionalization with less chemical consumption. To reveal the differences in reactivity and chemical consumption, we showed esterification of both native cellulose and ozone treated hydrolyzed cellulose. Based on the results, the molar mass of the starting cellulose has a significant effect on the end product's degree of substitution and properties. Furthermore, molar mass controlled palmitate esters form mechanically strong, flexible and optically transparent films with excellent water barrier properties. We anticipate that molar mass controlled cellulose will provide a starting point for the greater use of cellulose based materials, in various application, such as films and composites. PMID:27474646

  14. Periodontal healing after impacted lower third molar surgery in adolescents and adults. A prospective study.

    PubMed

    Kugelberg, C F; Ahlström, U; Ericson, S; Hugoson, A; Kvint, S

    1991-02-01

    The effects of impacted lower 3rd molar surgery on periodontal tissues in the adjacent 2nd molar area have been investigated in a prospective study comprising 176 cases from 2 age groups: less than or equal to 20 years (n = 93) and greater than or equal to 30 years (n = 83), respectively. The preoperative and 1-year postoperative examinations included both clinical and radiographic variables. All patients were subjected to a standardized surgical procedure and optimal plaque control pre-, intra- and postoperatively. Early removal of impacted lower 3rd molars with large angulation and close positional relationship to the adjacent 2nd molar proved to have a beneficial effect on periodontal health. PMID:2019777

  15. Simplifying Chemical Reactor Design by using Molar Quantities Instead of Fractional Conversion.

    ERIC Educational Resources Information Center

    Brown, Lee F.; Falconer, John L.

    1987-01-01

    Explains the advantages of using molar quantities in chemical reactor design. Advocates the use of differential versions of reactor mass balances rather than the integrated forms. Provides specific examples and cases to illustrate the principles. (ML)

  16. Management of Chronic Hyperplastic Pulpitis in Mandibular Molars of Middle Aged Adults- A Multidisciplinary Approach.

    PubMed

    Anilkumar, Kanakamedala; Lingeswaran, Somiya; Ari, Geetha; Thyagarajan, Ramakrishnan; Logaranjani, Anitha

    2016-01-01

    The molar tooth of children and young adults is a common site for chronic hyperplastic pulpitis (pulp polyp). It rarely occurs in middle aged adults. This condition is usually characterized by extensive involvement of the pulp, dictating the extraction of involved tooth. Extraction of permanent molars can lead to transient or permanent malocclusion, aesthetic, phonetic and functional problems. Here we report a case of pulp polyp in mandibular first molar of a 33-year-old woman that grew into the carious cavity. The aim of this case report is to describe the diagnosis of a chronic hyperplastic pulpitis involving the permanent molar as well as to describe its management in order to preserve them as a functional unit of the dentition. PMID:26894192

  17. Sexual dimorphism in crown units of mandibular deciduous and permanent molars in Australian Aborigines.

    PubMed

    Kondo, S; Townsend, G C

    2004-01-01

    Sexual differences in the crown units of mandibular molars were investigated in Australian Aborigines. The first and second deciduous molars (dm1 and dm2), and first to third permanent molars (M1, M2 and M3) were measured on dental casts using a sliding caliper. Measurements of tooth crowns included overall mesiodistal and buccolingual diameters, as well as the mesiodistal and buccolingual diameters of the trigonid and talonid. Percentage dimorphism values were greater in the talonid dimensions than the trigonid, indicating that sex differences tend to be larger in the later-developing crown units. Sex differences in mesiodistal diameters increased from dm1 to M2 but decreased for M3, the tooth that showed the least dimorphism of all the molars. This result seems to be due to the marked variability in size of the M3 between individuals. PMID:15553268

  18. Alternative approach to management of early loss of second primary molar: a clinical case report.

    PubMed

    Agarwal, Ravi; Chaudhry, Kalpna; Yeluri, Ramakrishna; Singh, Chanchal; Munshi, Autar K

    2014-05-01

    Preservation of space after premature loss of the second primary molar is essential to prevent mesial drifting of the permanent first molar. Various modifications of distal shoe space maintainers, which have been documented, are all nonfunctional in nature. This paper describes an innovative design of a functional distal shoe space maintainer that is intended to overcome the disadvantages of conventional non-functional space maintainers and that does not hamper the periodontal status of the abutment tooth. PMID:25087351

  19. Unilateral Maxillary First Molar Extraction in Class II Subdivision: An Unconventional Treatment Alternative

    PubMed Central

    Booij, J. W.; Livas, Christos

    2016-01-01

    The asymmetrical intra-arch relationship in Class II subdivision malocclusion poses challenges in the treatment planning and mechanotherapy of such cases. This case report demonstrates a treatment technique engaging unilateral extraction of a maxillary first molar and Begg fixed appliances. The outcome stability and the enhancing effect on the eruption of the third molar in the extraction segment were confirmed by a 4-year follow-up examination. PMID:27200194

  20. A geometric morphometric analysis of hominin lower molars: Evolutionary implications and overview of postcanine dental variation.

    PubMed

    Gómez-Robles, Aida; Bermúdez de Castro, José María; Martinón-Torres, María; Prado-Simón, Leyre; Arsuaga, Juan Luis

    2015-05-01

    Lower molars have been extensively studied in the context of hominin evolution using classic and geometric morphometric analyses, 2D and 3D approaches, evaluations of the external (outer enamel surface) and internal anatomy (dentine, pulp chamber, and radicular canals), and studies of the crown and root variation. In this study, we present a 2D geometric morphometric analysis of the crown anatomy of lower first, second, and third molars of a broad sample of hominins, including Pliocene and Lower, Middle, and Upper Pleistocene species coming from Africa, Asia, and Europe. We show that shape variability increases from first to second and third molars. While first molars tend to retain a relatively stable 5-cusped conformation throughout the hominin fossil record, second and third molars show marked distal reductions in later Homo species. This trend to distal reduction is similar to that observed in previous studies of premolars and upper second and third molars, and points to a correlated reduction of distal areas across the whole postcanine dentition. Results on lower molar variation, as well as on other postcanine teeth, show certain trends in European Pleistocene populations from the Atapuerca sites. Middle Pleistocene hominins from Sima de los Huesos show Neanderthal affinities and strong dental reduction, especially in the most distal molars. The degree of dental reduction in this population is stronger than that observed in classic Neanderthals. Homo antecessor hominins from Gran Dolina-TD6 have primitive lower teeth that contrast with their more derived upper teeth. The evolutionary implications of these dental affinities are discussed in light of recent paleogenetic studies. PMID:25840859

  1. Root Canal Therapy of a Mandibular First Molar with Five Root Canals: A Case Report

    PubMed Central

    Reyhani, Mohammad Frough; Rahimi, Saeed; Shahi, Shahriar

    2007-01-01

    A mandibular first molar requiring root canal therapy was found with five canals, three mesial canals, and two distal canals. Initially, four canals (mesiobuccal, mesiolingual, distobuccal, and distolingual) were identified. The mesiobuccal and mesiolingual canals were found in their normal locations, and a fifth canal was noted between these two. This case demonstrates a rare anatomical configuration and supplements previous reports of the existence of such configurations in mandibular first molars. PMID:24298291

  2. Unilateral Maxillary First Molar Extraction in Class II Subdivision: An Unconventional Treatment Alternative.

    PubMed

    Booij, J W; Livas, Christos

    2016-01-01

    The asymmetrical intra-arch relationship in Class II subdivision malocclusion poses challenges in the treatment planning and mechanotherapy of such cases. This case report demonstrates a treatment technique engaging unilateral extraction of a maxillary first molar and Begg fixed appliances. The outcome stability and the enhancing effect on the eruption of the third molar in the extraction segment were confirmed by a 4-year follow-up examination. PMID:27200194

  3. Comparison of sexual dimorphism of permanent mandibular canine with mandibular first molar by odontometrics

    PubMed Central

    Agrawal, Aditi; Manjunatha, Bhari Shranesha; Dholia, Bhavik; Althomali, Yousef

    2015-01-01

    Background and Objectives: Sexual dimorphism is one of important tool of forensic science. The objective of this study is to assess the dimorphic status of mesio-distal (MD) and bucco-lingual (BL) diameter of mandibular canine with mandibular first molar among the students of dental college. This study is of definite significance as sex chromosomes and hormonal production influenced tooth morphology. Materials and Methods: The descriptive study adopted the purposive sampling technique, of 50 male and 50 female aged 17-25 years, using study casts for mesio-distal and bucco-lingual dimensions of mandibular canine with mandibular first molar were taken using digital Vernier caliper. The data obtained were subjected to statistical analysis using descriptive statistics and t-test to compare MD and BL dimensions in male and female populations and P ≤ 0.05 was found statistically significant. Results: Sexual dimorphism can be predicted by measuring mesiodistal dimension of mandibular canine and mandibular first molar. The left mandibular canine showed more sexual dimorphism (12.66%) in comparison to left mandibular first molar (0.824%) only. Right mandibular canine showed greater dimorphism in MD dimensions (10.94%) in comparison to right mandibular first molar (6.96%). In bucco-lingual dimensions mandibular canine showed less variability when compared with mandibular first molar, thus our study showed more significance on mesio-distal dimensions of both teeth. Conclusion: The present study concludes statistically significant sexual dimorphism in mandibular canine over mandibular first molar on study casts. The MD dimensions in mandibular canine and mandibular first molar can help in determining sex and identification of unknown person. PMID:26816466

  4. Agenesis of premolar associated with submerged primary molar and a supernumerary premolar: An unusual case report

    PubMed Central

    Nirmala, S. V. S. G.; Sandeep, C.; Sivakumar, N.; Babu, M. S.; Lalitha, V.

    2012-01-01

    The combination of submerged primary molar, agenesis of permanent successor with a supernumerary in the same place is very rare. The purpose of this article is to report a case of submerged mandibular left second primary molar with supernumerary tooth in the same region along with agenesis of second premolar in an 11-year-old girl, its possible etiological factors, and a brief discussion on treatment options. PMID:22629079

  5. Spectrophotometric color evaluation of permanent incisors, canines and molars. A cross-sectional clinical study

    PubMed Central

    POP-CIUTRILA, IOANA-SOFIA; COLOSI, HORATIU ALEXANDRU; DUDEA, DIANA; BADEA, MANDRA EUGENIA

    2015-01-01

    Background and aims An accurate color reproduction represents the final validation level of an esthetic anterior or posterior restoration. The aim of this study was to evaluate the color of permanent maxillary incisors, canines and molars, using a clinical spectrophotometer. Methods The Vita Easyshade Advance 4.0® intraoral spectrophotometer was used by one clinician to determine the color of 369 permanent maxillary incisors, canines and molars. The best matches to Vitapan Classical® and 3D-Master® shade guides were recorded. A one-way analysis of variance and Kruskal-Wallis test were used to compare L*, a*, b*, c* and h* color coordinates among the 3 types of teeth. Differences between the mean values of all color coordinates were evaluated by use of Bonferroni corrections. Color difference (ΔE*) between incisors, canines and molars was calculated from ΔL*, Δa* and Δb* data and the results were compared to ΔE*=3.3 acceptability threshold. Results Except for Δa* and Δh* between canines and molars, statistically significant differences among the mean differences of all color coordinates were found when the 3 types of teeth were compared by pairs. The most frequently measured shades were A1 (48.4%), respectively 1M1 (31.5%) for incisors, B3 (36.6%), respectively 2M3 (39.8%) for canines and B3 (44.7%), respectively 2M3 (52%) for molars. Incisors had the highest lightness values, followed by canines and molars. Molars were the most chromatic with the highest a* and b* values. Conclusions Despite the limitations of this study, color differences among incisors, canines and molars were found to be statistically significant, above the clinical acceptability threshold established. In conclusion, successful esthetic restorations of permanent teeth of the same patient need an individual color assessment and reproduction of every type of tooth. PMID:26733753

  6. An in vitro assessment of type, position and incidence of isthmus in human permanent molars

    PubMed Central

    de LIMA, Fernando José Camello; MONTAGNER, Francisco; JACINTO, Rogério Castilho; AMBROSANO, Glaucia Maria Bovi; GOMES, Brenda Paula Figueiredo de Almeida

    2014-01-01

    Root canal anatomical complexities, such as isthmus, may limit the action of the endodontic instruments, irrigant solutions and intracanal medications, leading to endodontic treatment failure. Objectives This in vitro study assessed the type, position and incidence of isthmus in human permanent molars. Material and Methods One hundred and twenty eight upper and lower first and second permanent molars were analyzed. The roots were embedded in transparent resin, and then split at different distances from the apex (1.0-2.5-4.0-5.5-7.0 mm). Following the sample examination in stereomicroscope, the data were submitted to chi-square statistical test at a 5% significance level. Results The highest isthmus incidence was at 7.0 mm from the root apex in all samples, except the distal root of lower molars (at 5.5 mm). In upper and lower molars, type V (complete isthmus with a continuous opening between the two main root canals) was the most common classification of isthmus (28.8%). In the mesial root of first and second mandibular molars, type IV had the highest incidence (36% and 23.9%, respectively). Conclusion It was concluded that isthmus was widely found in flat roots, with a low percentage in areas close to the apex. In upper and lower molars, these structures were most frequently found at 7 mm from the apex. PMID:25141198

  7. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial.

    PubMed

    McNamara, Z; Findlay, G; O'Rourke, P; Batstone, M

    2016-05-01

    The treatment dilemma provided by asymptomatic third molars in mandibular angle fractures remains controversial. This prospective randomized controlled trial was undertaken to determine whether there is an advantage to extraction or retention of the third molar whilst repairing a mandibular angle fracture. Sixty-four patients were allocated randomly to the two treatment groups. All underwent open reduction and internal fixation (ORIF) with standard postoperative care. The primary outcome measure was uncomplicated fracture healing. Secondary measures were surgical duration, malocclusion, wound healing, nerve injury, and return to theatre. All patients had uncomplicated fracture healing. The incidence of nerve injury was 16% for the retention group compared with 39% for the removal group (P=0.038). The average operating time for ORIF and third molar retention cases was 58.5min and for ORIF and third molar removal cases was 66.3min (P=0.26). There was no statistically significant difference between groups for wound healing, occlusion outcomes, or return to theatre. Given the additional risk of nerve injury and the additional operating time required for removal of a third molar, in the absence of an absolute indicator for removal of the third molar, it appears justifiable to advise retaining the tooth in the line of a mandibular angle fracture. PMID:26867667

  8. Recommendations for Third Molar Removal: A Practice-Based Cohort Study

    PubMed Central

    Rothen, Marilynn; Spiekerman, Charles; Drangsholt, Mark; McClellan, Lyle; Huang, Greg J.

    2014-01-01

    Objectives. We investigated general dentists’ reasons for recommending removal or retention of third molars and whether patients adhered to dentists’ recommendations. Methods. In a 2-year prospective cohort study (2009–2011) in the Pacific Northwest, we followed 801 patients aged 16 to 22 years from 50 general dental practices. Generalized estimating equations logistic regressions related patient and dentist characteristics to dentists' recommendations to remove third molars and to patient adherence. Results. General dentists recommended removal of 1683 third molars from 469 (59%) participants, mainly to prevent future problems (79%) or because a third molar had an unfavorable orientation or was unlikely to erupt (57%). Dentists recommended retention and monitoring of 1244 third molars from 366 (46%) participants, because it was too early to decide (73%), eruption path was favorable (39%), or space for eruption was sufficient (26%). When dentists recommended removal, 55% of participants adhered to this recommendation during follow-up, and the main reason was availability of insurance (88%). Conclusions. General dentists frequently recommended removal of third molars for reasons not related to symptoms or pathology, but rather to prevent future problems. PMID:24524519

  9. A Novel Chitin Binding Crayfish Molar Tooth Protein with Elasticity Properties

    PubMed Central

    Tynyakov, Jenny; Bentov, Shmuel; Abehsera, Shai; Khalaila, Isam; Manor, Rivka; Katzir Abilevich, Lihie; Weil, Simy; Aflalo, Eliahu D.; Sagi, Amir

    2015-01-01

    The molar tooth of the crayfish Cherax quadricarinatus is part of the mandible, and is covered by a layer of apatite (calcium phosphate). This tooth sheds and is regenerated during each molting cycle together with the rest of the exoskeleton. We discovered that molar calcification occurs at the pre-molt stage, unlike calcification of the rest of the new exoskeleton. We further identified a novel molar protein from C. quadricarinatus and cloned its transcript from the molar-forming epithelium. We termed this protein Cq-M13. The temporal level of transcription of Cq-M13 in an NGS library of molar-forming epithelium at different molt stages coincides with the assembly and mineralization pattern of the molar tooth. The predicted protein was found to be related to the pro-resilin family of cuticular proteins. Functionally, in vivo silencing of the transcript caused molt cycle delay and a recombinant version of the protein was found to bind chitin and exhibited elastic properties. PMID:26010981

  10. A novel chitin binding crayfish molar tooth protein with elasticity properties.

    PubMed

    Tynyakov, Jenny; Bentov, Shmuel; Abehsera, Shai; Khalaila, Isam; Manor, Rivka; Katzir Abilevich, Lihie; Weil, Simy; Aflalo, Eliahu D; Sagi, Amir

    2015-01-01

    The molar tooth of the crayfish Cherax quadricarinatus is part of the mandible, and is covered by a layer of apatite (calcium phosphate). This tooth sheds and is regenerated during each molting cycle together with the rest of the exoskeleton. We discovered that molar calcification occurs at the pre-molt stage, unlike calcification of the rest of the new exoskeleton. We further identified a novel molar protein from C. quadricarinatus and cloned its transcript from the molar-forming epithelium. We termed this protein Cq-M13. The temporal level of transcription of Cq-M13 in an NGS library of molar-forming epithelium at different molt stages coincides with the assembly and mineralization pattern of the molar tooth. The predicted protein was found to be related to the pro-resilin family of cuticular proteins. Functionally, in vivo silencing of the transcript caused molt cycle delay and a recombinant version of the protein was found to bind chitin and exhibited elastic properties. PMID:26010981

  11. Prevalence of Third Molar Agenesis: Associated Dental Anomalies in Non-Syndromic 5923 Patients.

    PubMed

    Sujon, Mamun Khan; Alam, Mohammad Khursheed; Rahman, Shaifulizan Abdul

    2016-01-01

    The aim of this study was to investigate the prevalence of third molar agenesis and other associated dental anomalies in Bangladeshi population and to investigate the relationship of other dental anomalies with the third molar presence/agenesis. A retrospective study was performed using panoramic radiographs of 5923 patients, who ranged in age from 10 to 50 years. All radiographs were analyzed by Planmeca Romexis® 3.0 software (Planmeca Oy, Helsinki, Finland). Pearson chi-square and one way ANOVA (Post Hoc) test were conducted. The prevalence of third molar agenesis was 38.4%. The frequency of third molar agenesis was significantly higher in females than males (p <0.025). Third molar agenesis was significantly more prevalent in maxilla as compared to mandible (p <0.007). The prevalence of other dental anomalies was 6.5%, among them hypodontia was 3.1%. Prevalence of third molar agenesis varies in different geographic region. Among the other dental anomalies hypodontia was more prevalent. PMID:27580050

  12. A reliable method for evaluating upper molar distalization: Superimposition of three-dimensional digital models

    PubMed Central

    Nalcaci, Ruhi; Bicakci, Ali Altug; Ozturk, Firat; Babacan, Hasan

    2015-01-01

    Objective The aim of this study was to evaluate the reliability of measurements obtained after the superimposition of three-dimensional (3D) digital models by comparing them with those obtained from lateral cephalometric radiographs and photocopies of plaster models for the evaluation of upper molar distalization. Methods Data were collected from plaster models and lateral cephalometric radiographs of 20 Class II patients whose maxillary first molars were distalized with an intraoral distalizer. The posterior movements of the maxillary first molars were evaluated using lateral cephalometric radiographs (group CP), photocopies of plaster models (group PH), and digitized 3D models (group TD). Additionally, distalization and expansion of the other teeth and the degrees of molar rotation were measured in group PH and group TD and compared between the two groups. Results No significant difference was observed regarding the amount of molar distalization among the three groups. A comparison of the aforementioned parameters between group PH and group TD did not reveal any significant difference. Conclusions 3D digital models are reliable to assess the results of upper molar distalization and can be considered a valid alternative to conventional measurement methods. PMID:25798414

  13. 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

  14. Enamel-dentine junction (EDJ) morphology distinguishes the lower molars of Australopithecus africanus and Paranthropus robustus.

    PubMed

    Skinner, Matthew M; Gunz, Philipp; Wood, Bernard A; Hublin, Jean-Jacques

    2008-12-01

    Tooth crown morphology plays a central role in hominin systematics, but the removal of the original outer enamel surface by dental attrition often eliminates from consideration the type of detailed crown morphology that has been shown to discriminate among hominin taxa. This reduces the size of samples available for study. The enamel-dentine junction (EDJ) is the developmental precursor and primary contributor to the morphology of the unworn outer enamel surface, and its morphology is only affected after considerable attrition. In this paper, we explore whether the form of the EDJ can be used to distinguish between the mandibular molars of two southern African fossil hominins: Paranthropus (or Australopithecus) robustus and Australopithecus africanus. After micro-computed tomographic scanning the molar sample, we made high-resolution images of the EDJ and used geometric morphometrics to compare EDJ shape differences between species, in addition to documenting metameric variation along the molar row within each species. Landmarks were collected along the marginal ridge that runs between adjacent dentine horns and around the circumference of the cervix. Our results suggest that the morphology of the EDJ can distinguish lower molars of these southern African hominins, and it can discriminate first, second, and third molars within each taxon. These results confirm previous findings that the EDJ preserves taxonomically valuable shape information in worn teeth. Mean differences in EDJ shape, in particular dentine horn height, crown height, and cervix shape, are more marked between adjacent molars within each taxon than for the same molar between the two taxa. PMID:18824253

  15. A crayfish molar tooth protein with putative mineralized exoskeletal chitinous matrix properties.

    PubMed

    Tynyakov, Jenny; Bentov, Shmuel; Abehsera, Shai; Yehezkel, Galit; Roth, Ziv; Khalaila, Isam; Weil, Simy; Berman, Amir; Plaschkes, Inbar; Tom, Moshe; Aflalo, Eliahu D; Sagi, Amir

    2015-11-01

    Some crustaceans possess exoskeletons that are reinforced with calcium carbonate. In the crayfish Cherax quadricarinatus, the molar tooth, which is part of the mandibular exoskeleton, contains an unusual crystalline enamel-like apatite layer. As this layer resembles vertebrate enamel in composition and function, it offers an interesting example of convergent evolution. Unlike other parts of the crayfish exoskeleton, which is periodically shed and regenerated during the molt cycle, molar mineral deposition takes place during the pre-molt stage. The molar mineral composition transforms continuously from fluorapatite through amorphous calcium phosphate to amorphous calcium carbonate and is mounted on chitin. The process of crayfish molar formation is entirely extracellular and presumably controlled by proteins, lipids, polysaccharides, low-molecular weight molecules and calcium salts. We have identified a novel molar protein termed Cq-M15 from C. quadricarinatus and cloned its transcript from the molar-forming epithelium. Its transcript and differential expression were confirmed by a next-generation sequencing library. The predicted acidic pI of Cq-M15 suggests its possible involvement in mineral arrangement. Cq-M15 is expressed in several exoskeletal tissues at pre-molt and its silencing is lethal. Like other arthropod cuticular proteins, Cq-M15 possesses a chitin-binding Rebers-Riddiford domain, with a recombinant version of the protein found to bind chitin. Cq-M15 was also found to interact with calcium ions in a concentration-dependent manner. This latter property might make Cq-M15 useful for bone and dental regenerative efforts. We suggest that, in the molar tooth, this protein might be involved in calcium phosphate and/or carbonate precipitation. PMID:26385331

  16. Radiographic findings on 3rd molars removed in 20-year-old men.

    PubMed

    Rajasuo, Ari; Peltola, Jaakko; Ventä, Irja; Murtomaa, Heikki

    2003-10-01

    In this study we assess radiographic findings characteristic of mandibular 3rd molars that had required either routine or surgical extraction. X-ray findings relating to acute pericoronitis were also examined. The material was collected by investigating patient records and rotational panoramic radiographs of 20-year-old Finnish male conscripts (n = 738) treated during military service because of 3rd-molar-related problems. The follicle around the crown of mandibular 3rd molars with acute pericoronitis was enlarged in 19% of cases and in 13% of chronic symptom-free pericoronitis cases (not statistically significant difference). Mandibular 3rd molars extracted surgically were more often mesially inclined than those extracted routinely (61% vs. 23%; P < 0.001), partially or totally intrabony impacted (92% vs. 66%; P < 0.001) and deep situated (on average 4.2 mm vs. 2.5 mm under the occlusal plane). Surgical extraction was also associated with the roots completely developed [92% vs. 84% of the teeth routinely extracted, odds ratio (OR) 2.6, 95% confidence interval (CI) 1.2-5.5] and with the absence of radiographic pericoronitis [around 27% vs. 39% of the teeth routinely extracted (OR 0.5, 95% CI 0.3-0.8)]. In 86% of cases the space between 2nd molar and ramus of the mandible was narrower than the 3rd molar extracted surgically, whereas this was 62% in routine extraction cases (P < 0.001). We conclude that there are some typical 3rd-molar findings in rotational panoramic radiographs that show a need for surgical extraction. PMID:14763776

  17. Comparison of K-loop Molar Distalization with that of Pendulum Appliance - A Prospective Comparative Study

    PubMed Central

    Shashidhar, Nagam Reddy; Reddy, S.Rama Koteswara

    2016-01-01

    Introduction Molar distalization is the non extraction method of managing Class II malocclusions. Aim The purpose of this study was to evaluate the skeletal and dentoalveolar effects of maxillary molar distalization with K-loop appliance, and to compare these effects with that of pendulum group. Materials and Methods Class I and dental Class II malocclusions were divided into two groups of 15 each: In Group 1 (nine females and six males; mean age, 16.0±2.6 years) patients were treated with K-Loop molar distalization supported palatally by Nance button, while in Group 2 (seven females and eight males; mean age, 15.4±4.7 years), the patients were treated with conventional pendulum appliance. Standardized lateral cephalograms were taken at the beginning of treatment (T0) and at the end of molar distalization (T1) and the changes were statistically analyzed with paired t-test. Results The results showed no statistically significant difference in the amount of molar distalization in either of the appliance groups: the mean amount of molar distal movement of 5.1±0.8 mm and 4.93±1.68 mm was observed in the Group 1 and 2 respectively. The incisors moved mesially by 1.3±0.63 mm in Group 1 and 1.57±0.58 mm in Group 2. Conclusion K-Loop molar distalizing appliance has similar skeletal and dentoalveolar effects as that of pendulum appliance, with the advantages of simple yet efficient to control the moment-force ratio to produce all types of tooth movements and also requires minimal patient co-operation. PMID:27504403

  18. The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses

    SciTech Connect

    Reynolds, Jacob G.

    2013-01-11

    Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOH-NaAl(OH{sub 4}H{sub 2}O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H{sub 2}O, NaOH, and NaAl(OH){sub 4} are determined. The equivalence of the CSLM and the graphical method is verified by comparing results detennined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components.

  19. Evaluation of root canal morphology of human primary molars by using CBCT and comprehensive review of the literature.

    PubMed

    Ozcan, Gozde; Sekerci, Ahmet Ercan; Cantekin, Kenan; Aydinbelge, Mustafa; Dogan, Salih

    2016-05-01

    Objective Knowledge of primary tooth morphology is essential for clinical dentistry, especially for root canal treatment and dental traumatology. However, this has not been well documented to date with a large sample. This study was carried out to investigate the variation in number and morphology of the root canals of the primary molars, to study the applicability of cone beam computerized tomography (CBCT) in assessing the same and to provide a comprehensive review of the literature. Materials and methods A total of 343 primary molars, without any root resorption, were divided into four main groups including the maxillary first molars, maxillary second molars, mandibular first molars and mandibular second molars. All of them were analysed in CBCT images in the axial, sagittal and coronal planes. Various parameters such as the number of roots, number of canals, the root canal type, diameter of root and root canal and root canal curvature were studied. Results Primary molars in all four groups showed variability in the number of roots and root canals. As far as length of the roots was concerned, the palatal root of the maxillary molar was found to be longest, while the distobuccal root was shortest. In mandibular molars, the mesial root was longer than the distal root. The length of distobuccal root canal of the maxillary molars and the distolingual canal of the mandibular molars was found to be shortest. The number of roots and root canals varied from two to four and three to four, respectively. The maxillary molars exhibited more one-canal than two-canal roots. Conclusion The present study provides comprehensive information to the existing literature concerning the variation in root canal morphology of the maxillary and mandibular primary molar teeth. These data may help clinicians in the root canal treatment of these teeth. PMID:26523502

  20. Compositional dependent partial molar volume and compressibility of CO2 in rhyolite, phonolite and basalt glasses

    NASA Astrophysics Data System (ADS)

    Lerch, P.; Seifert, R.; Malfait, W. J.; Sanchez-Valle, C.

    2012-12-01

    Carbon dioxide is the second most abundant volatile in magmatic systems and plays an important role in many magmatic processes, e.g. partial melting, volatile saturation, outgassing. Despite this relevance, the volumetric properties of carbon-bearing silicates at relevant pressure and temperature conditions remain largely unknown because of considerable experimental difficulties associated with in situ measurements. Density and elasticity measurements on quenched glasses can provide an alternative source of information. For dissolved water, such measurements indicate that the partial molar volume is independent of compositions at ambient pressure [1], but the partial molar compressibility is not [2, 3]. Thus the partial molar volume of water may depend on melt composition at elevated pressure. For dissolved CO2, no such data is available. In order to constrain the effect of magma composition on the partial molar volume and compressibility of dissolved carbon, we determined the density and elasticity for three series of carbon-bearing basalt, phonolite and rhyolite glasses, quenched from 3.5 GPa and relaxed at ambient pressure. The CO2 content varies between 0 to 3.90 wt% depending on the glass composition. Glass densities were determined using the sink/float method in a diiodomethane (CH2I2) - acetone mixture. Brillouin measurements were conducted on relaxed and unrelaxed silicate glasses in platelet geometry to determine the compressional (VP) and shear (VS) wave velocities and elastic moduli. The partial molar volume of CO2 in rhyolite, phonolite and basalt glasses is 25.4 ± 0.9, 22.1 ± 0.6 and 26.6 ±1.8 cm3/mol, respectively. Thus, unlike for dissolved water, the partial molar volume of CO2 displays a resolvable compositional effect. Although the composition and CO2/carbonate speciation of the phonolite glasses is intermediate between that of the rhyolite and basalt glasses, the molar volume is not. Similar to dissolved water, the partial molar bulk modulus

  1. Pathological (late) fractures of the mandibular angle after lower third molar removal: a case series

    PubMed Central

    2013-01-01

    Introduction Pathological (late) fracture of the mandibular angle after third molar surgery is very rare (0.005% of third molar removals). There are 94 cases reported in the literature; cases associated with osseous pathologies such as osteomyelitis or any local and systemic diseases that may compromise mandibular bone strength have not been included. We describe three new cases of pathological (late) fracture of the mandibular angle after third molar surgery. Case presentations The first patient was a 27-year-old Caucasian man who had undergone surgical removal of a 3.8, mesioangular variety, class II-C third molar 20 days before admission to our clinic. The fracture of his left mandibular angle, complete and composed, occurred during chewing. The second patient was a 32-year-old Caucasian man. He had undergone surgical removal of a 3.8, mesioangular variety, class II-B third molar 22 days before his admission. The fracture, which occurred during mastication, was studied by computed tomography that showed reparative tissue in the fracture site. The third patient was a 36-year-old Caucasian man who had undergone surgical removal of a 3.8, vertical variety, class II-C third molar 25 days before the observation. In this case the fracture of his mandibular angle was oblique (unfavorable), complete and composed. The fracture had occurred during chewing. We studied the fracture by optical projection tomography and computed tomography. All of the surgical removals of the 3.8 third molars, performed by the patients’ dentists who had more than 10 years of experience, were difficult. We treated the fractures with open surgical reduction, internal fixation by titanium miniplates and intermaxillary elastic fixation removed after 6 weeks. Conclusions The literature indicates that the risk of pathological (late) fracture of the mandibular angle after third molar surgery for total inclusions (class II-III, type C) is twice that of partial inclusions due to the necessity of

  2. Mandibular molar displacement secondary to the use of forces to retract the maxilla.

    PubMed

    Ben-Bassat, Y; Baumrind, S; Korn, E L

    1986-01-01

    Using previously described computer-aided techniques, we have been able to characterize quantitatively the displacements of the lower first molar associated with the use of several different therapeutic modalities that are conventionally employed to retract the maxilla in the treatment of Class II malocclusion. The total displacement of the molar has been partitioned into two components associated respectively with displacement of the entire mandible and with local interosseous migration (dental compensation) of the molar within the mandible. A further attempt has been made to partition treatment-associated effects from nontreatment-associated effects. While considerable variability in effect was observed within each sample on a case-by-case basis, some important normative trends did emerge. Contrary to our expectations, it was found that in each of the treatment groups, the mean local intraosseous rotational effect (Table IIB.2) was of greater magnitude than the mean effect of mandibular rotation (Table IIB.1). The character of the intraosseous rotation differed significantly (P less than 0.05) between the control group and each of the treatment groups. In the control group, a mean mesial crown tipping (that is, "proclination") was noted. In each of the treatment groups, a mean distal crown tipping ("uprighting") was noted. In both the cervical and intraoral groups, the lower molar tended to displace mesially more than in the control or high-pull groups. This mesial displacement derived from the mesial displacement of the mandible (Table IIC.3), rather than from displacement of the tooth within the bone (Table IIC.4). In both the high-pull and the intraoral groups, the lower molar erupted within the mandible significantly more than in the control and cervical groups (Table IIC.6). The statistically significant supereruption/extrusion of the upper molar in the cervical group (Table IIC.2) was not accompanied by an associated inhibition of the eruption of the lower

  3. Containing the cost of third-molar extractions: a dilemma for health insurance.

    PubMed Central

    Friedman, J W

    1983-01-01

    No known scientific studies support the extraction of third molars (wisdom teeth) to prevent future disease. Yet, third-molar surgery for this purpose has become so common that in at least one major U.S. health insurance plan, the cumulative cost exceeds that for every other kind of major surgery. Many third molars that are developing normally in adolescents are classified as impacted and removed before they erupt, a practice that results in large expenditures for unnecessary surgery. In addition, the difficulty of the extractions is frequently exaggerated, so that patients and insurance plans are overcharged. Third molar surgery is not without risk of iatrogenic injury. Fracture of the jaw, permanent numbness of the lip (paresthesia), and injury to other teeth may occur. This paper presents a mechanism for containing the cost of third-molar surgery by elimination of payment for nonessential extractions and of the related overcharges. Adoption of this policy by administrators of dental insurance plans would save millions of dollars each year, money that could be better used in providing care for more people with real dental disease. PMID:6611824

  4. Anatomical Relationship of Lingual Nerve to the Region of Mandibular Third Molar

    PubMed Central

    de Carvalho Leite Leal Nunes, Carla Maria; de Almeida Lopes, Maria Cândida

    2013-01-01

    ABSTRACT Objectives This study evaluated the relationship of the lingual nerve with the adjacent anatomical structures of the mandibular third molar region, influencing the dentist to be aware of the variability of these relationships. Material and Methods Samples of 24 human corpse half-heads were selected and divided according with the presence or absence of the mandibular third molars. The lingual nerve (LN) was explored, showing its run from the oblique line until its crossing with the submandibular gland duct. The measurements along the LN and the adjacent anatomical structures were taken at the retromolar, molar and sublingual region with the use of a digital caliper. Results The distance from the LN and the third molar socket, which represents the horizontal distance of the lingual plate to the nerve, on average, was 4.4 mm (SD 2.4 mm). The distance from the LN and the lingual alveolar rim, which represents the vertical relationship between the nerve and the lingual alveolar rim of the third molar socket, on average, was 16.8 mm (SD 5.7 mm). The LN has a varied topography that leaves it very vulnerable during any procedure executed in this region. Conclusions Unless adequate protection of the lingual nerve is acquired by following an adequate surgical technique, the lingual nerve will always be vulnerable to damage during surgical intervention or manipulation in this region. PMID:24478912

  5. Ectopic third molar in the mandibular condyle: A review of the literature

    PubMed Central

    Iglesias-Martin, Fernando; Torres-Carranza, Eusebio; Prats-Golczer, Victoria-Eugenia; Garcia-Perla-Garcia, Alberto

    2012-01-01

    Objectives: To evaluate the etiopathogenesis, clinical features, therapeutic options, and surgical approaches for removal of ectopic third molars in the mandibular condyle. Study design: MEDLINE search of articles published on ectopic third molars in the mandibular condyle from 1980 to 2011. 14 well-documented clinical cases from the literature were evaluated together with a new clinical case provided by the authors, representing a sample of 15 patients. Results: We found a mean age at diagnosis of 48.6 years and a higher prevalence in women. In 14 patients, associated radiolucent lesions were diagnosed on radiographic studies and confirmed histopathologically as odontogenic cysts. Clinical symptoms were pain and swelling in the jaw or preauricular region, trismus, difficulty chewing, cutaneous fistula and temporomandibular joint dysfunction. Treatment included conservative management in one case and in the other cases, surgical removal by intra- or extraoral approaches, the latter being the most common approach carried out. In most reported cases, serious complications were not outlined. Conclusions: The etiopathogenic theory involving odontogenic cysts in the displacement of third molars to the mandibular condyle seems to be the most relevant. They must be removed if they cause symptoms or are associated with cystic pathology. The surgical route must be planned according to the location and position of the ectopic third molar, and the possible morbidity associated with surgery. Key words:Third molar, ectopic tooth, condyle, mandible. PMID:22926463

  6. Prevalence of cysts and tumors around the retained and unerupted third molars in the Indian population

    PubMed Central

    Patil, Santosh; Halgatti, Vishal; Khandelwal, Suneet; Santosh, B.S.; Maheshwari, Sneha

    2014-01-01

    Aim Tooth impaction is a frequent phenomena and surgical removal of these teeth are the commonest of the dental surgical procedures. The debate over the removal of asymptomatic impacted third molars still continues. The aim of this retrospective study was to determine the incidence of development of cysts and tumors around the retained and unerupted third molars in the Indian population. Material and methods 5486 impacted third molars of 4133 patients were studied through the panoramic radiographs for the presence of associated cysts and tumors. The ages of the patients ranged from 17 to 67 years, with a mean of 33.7 years. The results were evaluated using the Pearson chi-square test. P-values less than 0.05 were considered to be statistically significant. Results There were 134 cysts (2.24%) and 63 tumors (1.16%) found that were associated with impacted third molars, of which 3 were malignant (0.05%). 143 patients had symptoms such as swelling or pain due to cystic or neoplastic lesions. The remainder 54 patients had no symptoms suggestive of pathology. The most common cyst was dentigerous cyst and the most common tumor was ameloblastoma. Conclusion The results indicate that cysts and tumors do develop in a relatively small but still considerable minority of patients. The fact that a considerable number of patients had no signs or symptoms indicating pathology is certainly worth considering. Consultation should be sought from dental specialists if there are symptoms in the third molar region. PMID:25737923

  7. Cysts in Periradicular Region of Deciduous Molars in Mixed Dentition: Retrospective Study of Five Cases

    PubMed Central

    Chavan, Ankush; Wadde, Kavita; Dewalwar, Vishal

    2014-01-01

    ABSTRACT% The cyst in mixed dentition stage cause expansion of buccal cortex, displacement of teeth and may present as case of infection. The cyst in periradicular region of deciduous molar are of frequent occurrence. The differential diagnosis of this lesion is radicular cysts of deciduous molar: developmental or infammatory dentigerous cyst of corresponding unerupted premolar. After going through the available literature of radicular cyst of deciduous molars and dentigerous cysts of developing premolars in mixed dentition we studied the five cases of cyst in periradicular region of deciduous molars in mixed dentition retrospectively for the diagnostic dilemma of radicular cyst verses dentigerous cyst. In conclusion, we can set some criteria for the diagnosis which is particularly important for treatment and for conservation of developing premolar. How to cite this article: Manekar VS, Chavan A, Wadde K, Dewalwar V. Cysts in Periradicular Region of Deciduous Molars in Mixed Dentition: Retrospective Study of Five Cases. Int J Clin Pediatr Dent 2014;7(3):229-235. PMID:25709310

  8. Structural Morphology of Molars in Large Mammalian Herbivores: Enamel Content Varies between Tooth Positions

    PubMed Central

    Winkler, Daniela E.; Kaiser, Thomas M.

    2015-01-01

    The distribution of dental tissues in mammalian herbivores can be very different from taxon to taxon. While grazers tend to have more elaborated and complexly folded enamel ridges, browsers have less complex enamel ridges which can even be so far reduced that they are completely lost. The gradient in relative enamel content and complexity of structures has so far not been addressed within a single species. However, several studies have noted tooth position specific wear rates in small mammals (rabbits, guinea pigs) which may be related to individual tooth morphology. We investigate whether differentiated enamel content by tooth position is also to be found in large herbivores. We use CT-scanning techniques to quantify relative enamel content in upper and lower molar teeth of 21 large herbivorous mammal species. By using a broad approach and including both perissodactyls and artiodactyls, we address phylogenetic intraspecific differences in relative enamel content. We find that enamel is highly unevenly distributed among molars (upper M1, M2, M3 and lower m1, m2, m3) in most taxa and that relative enamel content is independent of phylogeny. Overall, relative enamel content increases along the molar tooth row and is significantly higher in lower molars compared to upper molars. We relate this differential enamel content to prolonged mineralisation in the posterior tooth positions and suggest a compensatory function of m3 and M3 for functional losses of anterior teeth. PMID:26313359

  9. Third molar observations in a sample of British male young offenders.

    PubMed

    Andrews, Sally E

    2015-07-01

    Development, morphology and eruption of third molars are highly variable, and it is generally accepted that the emergence time is between the ages of 17 and 21 years. This study reports on variation in timing encountered in a sample of 155 young males (15-18 years) of British nationality who were detained at Her Majesty's Prison and Young Offenders Institution (HMP&YOI) Ashfield as young offenders. All 155 participants were self-reported in terms of their chronological age and their ethnic origin. Of the 17 year-olds, 68% of Black males displayed one or more erupted third molars compared to 39% of the White males. For those who were of mixed ancestry, 50% showed evidence of eruption of at least one third molar in this age group. This difference between Black and White ethnicity was further supported when missing first or second molars were taken into consideration. Whilst it has been suggested in the literature that ethnicity plays no major part in eruption timings for the third molars, this clinical observation poses some interesting questions about the accuracy of dental age assessment. PMID:26087875

  10. The incidence of cysts and tumors associated with impacted third molars

    PubMed Central

    Vigneswaran, A. T.; Shilpa, S.

    2015-01-01

    Incidence of cysts and tumors associated with lower impacted third molars are very low prevalence, which might be because of the fact that most pathologies go unnoticed as many practitioners discard the erupted tissue after surgical removal of the impacted teeth rather than sending the tissue for histopathological examination. Our aim was to evaluate the patients who came for third molar surgical removal with due therapeutic prophylacis and an incidental finding. A proper study protocol both inclusion and exclusion criteria was strictly followed for all the cases, which were included in the study. The period of study was 6 years and the total number of cases assessed were 2778 patients out of which 70 cases reported pathology associated with the impacted third molars. Among 70 cases 61.4% were reported as cyst and tumors and 38.6% of the cases had chronic inflammatory reaction, including two cases with normal dental follicle. High incidence rate of pathology associated with third molar occurred between age group of 20 and 30 years older age groups showed very low incidence. Most common site of impaction was found to be left side of mandible and positions were vertical and distoangular impactions. Thus was male predominance in the younger groups. The examination is necessary whether the third molars impacted cases were symptomatic or asymptomatic PMID:26015725

  11. Efficacy of fentanyl transdermal patch in pain control after lower third molar surgery: A preliminary study

    PubMed Central

    Vasovic, Miroslav; Andric, Miroslav; Todorovic, Ljubomir; Kokovic, Vladimir

    2016-01-01

    Background Surgical removal of impacted lower third molars is a common oral surgical procedure, generally followed by moderate to severe postoperative pain. Transdermal drug delivery as a concept offers interesting possibilities for postoperative pain control. The aim of this study was to evaluate the efficacy of transdermal system with fentanyl in relieving pain following impacted lower third molar surgery. Material and Methods Seventeen patients with bilateral impacted lower third molars were included in this preliminary study. For postoperative pain control, patients randomly received a fentanyl patch plus placebo tablet after the first operation and regular (placebo) patch and an analgesic, after the second operation. Analgesia was evaluated during first 24 hours postoperatively according to patients’ reports about time of first pain appearance and additional analgesic consumption. Pain severity was rated using a 10 cm long visual analogue scale (VAS). Results Intensity of postoperative pain and postoperative analgesic consumption were significantly lower after the Fentanyl Transdermal System (FTS) was applied (p<0.05). Duration of postoperative analgesia was significantly higher with FTS when compared to control treatment (p<0.05). Conclusions Based on the results of this preliminary study, transdermal system with fentanyl significantly reduced postoperative pain after third molar surgery. Key words:Analgesia, fentanyl, transdermal administration, third molar surgery, acute pain, postoperative care. PMID:27475691

  12. [Application of composite resin inlays to deciduous molars--a clinical observation of the resin onlay].

    PubMed

    Yamamoto, H; Iyori, H; Kanomi, R; Yao, K; Hieda, T

    1990-01-01

    Although composite resin has been used as an aesthetic restorative material, wear and fracture of the resin of fracture of the tooth structure are likely to occur when the size of the dental cavities are large. In addition to the lack of the aesthetic value, clinical results of prefabricated metal crown revealed several problems which were caused by the wear of the metal and the ill-adaptation of the cervical margin. In the present study, 50 devitalized deciduous molars were treated with composite resin onlays which were designed to cover the entire occlusal surface of the deciduous molar, and the clinical results were evaluated for a 6 month period. Additionally, for the purpose of simplification of the laboratory process for making resin onlays, ready-made occlusal shells were fabricated. The variety of the prepared shell size consisted of 7 sizes for the first deciduous molar, 9 sizes for the upper second deciduous molar and 10 sizes for the lower deciduous molar. The following results were obtained. 1) A partial resin fracture at the peripheral area of the mesio-buccal cuspid was found in five cases out of 50. 2) A glossy appearance on the surface of the onlay which was created by coated unfilled resin disappeared after 6 months of observation. 3) In relation to the resin onlay, when the antagonistic tooth was restored with prefabricated metal crowns, holes were made by attrition on all the crowns within a 3-4 month period.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2133972

  13. Molar Incisor Hypomineralization: An Epidemiological Study with Prevalence and Etiological Factors in Indian Pediatric Population

    PubMed Central

    Pandey, Ramesh K

    2016-01-01

    ABSTRACT Aims: To determine the prevalence of molar incisor hypomineralization (MIH) in Indian children and to analyze the possible etiological factors. Materials and methods: First permanent molars and all permanent incisors were examined in 1,369 children aged 8 to 12 years. Examinations were performed by two calibrated observers. The subjects were evaluated using judgment criteria proposed by Weerheijm et al in 2003. The parents accompanying children were given a questionnaire regarding pre- and postnatal history of the children. Results: A total of 191 children were diagnosed with MIH with a prevalence of 13.9%. Chi-square/Fisher exact test was used to compare the dichotomous variables. The relative risk with its 95% confidence interval was calculated to find the risk of clinical infections, such as chicken pox, jaundice, renal disorders, cardiac disorders, and affected molars with sex and type of delivery. Pre- and postnatal history of infection in a child was significantly correlated with the prevalence of MIH. Conclusion: The prevalence of MIH was 13.9% in the age group of 8 to 12 years. Prenatal and postnatal infections play an important role in hypomineralization of molars and incisors. How to cite this article: Mishra A, Pandey RK. Molar Incisor Hypomineralization: An Epidemiological Study with Prevalence and Etiological Factors in Indian Pediatric Population. Int J Clin Pediatr Dent 2016;9(2):167-171. PMID:27365942

  14. Treatment of 3rd molar-induced periodontal defects with guided tissue regeneration.

    PubMed

    Oxford, G E; Quintero, G; Stuller, C B; Gher, M E

    1997-07-01

    Recent reports provide evidence of increased attachment levels when using guided tissue regeneration (GTR) techniques for the treatment of periodontal defects. Periodontal defects frequently occur at the distal aspect of mandibular 2nd molars which are next to mesioangular impacted 3rd molars that have oral communication. The purpose of this study was to determine whether the use of GTR can enhance probing attachment levels (PALs) following extraction of mesioangular impacted third molars. 12 patients with bilateral soft tissue impacted mandibular 3rd molars entered this split mouth study. After extractions, the previously exposed distal root surface of the 2nd molars were debrided. The defects on the randomly selected experimental sites were covered with expanded polytetraflouro-ethylene (e-PTFE) membrane and the tissue was replaced to cover the membrane. Membranes were removed after 6 weeks. Control sites were treated identically except no membrane was placed. GI, P1I, PD, PAL and BOP records were obtained at 0, 3 and 6 months. The use of barrier material did not provide statistically-significant differences in PAL when comparing experimental versus control sites. Nevertheless, PAL gain was consistently greater at 3 and 6 months when GTR techniques were used in sites with deep impactions. PMID:9226386

  15. The incidence of cysts and tumors associated with impacted third molars.

    PubMed

    Vigneswaran, A T; Shilpa, S

    2015-04-01

    Incidence of cysts and tumors associated with lower impacted third molars are very low prevalence, which might be because of the fact that most pathologies go unnoticed as many practitioners discard the erupted tissue after surgical removal of the impacted teeth rather than sending the tissue for histopathological examination. Our aim was to evaluate the patients who came for third molar surgical removal with due therapeutic prophylacis and an incidental finding. A proper study protocol both inclusion and exclusion criteria was strictly followed for all the cases, which were included in the study. The period of study was 6 years and the total number of cases assessed were 2778 patients out of which 70 cases reported pathology associated with the impacted third molars. Among 70 cases 61.4% were reported as cyst and tumors and 38.6% of the cases had chronic inflammatory reaction, including two cases with normal dental follicle. High incidence rate of pathology associated with third molar occurred between age group of 20 and 30 years older age groups showed very low incidence. Most common site of impaction was found to be left side of mandible and positions were vertical and distoangular impactions. Thus was male predominance in the younger groups. The examination is necessary whether the third molars impacted cases were symptomatic or asymptomatic. PMID:26015725

  16. Coronectomy of impacted mandibular third molars: A meta-analysis and systematic review of the literature

    PubMed Central

    Cervera-Espert*, Juan; Pérez-Martínez*, Sara; Cervera-Ballester, Juan; Penarrocha-Oltra, David

    2016-01-01

    Background Coronectomy is an alternative to complete removal of an impacted mandibular third molar. Most authors have recommended coronectomy to prevent damage to the inferior alveolar nerve during surgical extraction of lower third molars. The present study offers a systematic review and metaanalysis of the coronectomy technique. Material and Methods A systematic review and meta-analysis was performed based on a PubMed and Cochrane databases search for articles published from 2014 and involving coronectomy of mandibular third molars located near the inferior alveolar nerve canal, with a minimum of 10 cases and a minimum follow-up period of 6 months. After application of the inclusion and exclusion criteria, a total of 12 articles were included in the study. Results and Discussion Coronectomy results in significantly lesser loss of sensitivity of the inferior alveolar nerve and prevents the occurrence of dry socket. No statistically significant differences were observed in the incidence of pain and infection between coronectomy and complete surgical extraction. After coronectomy, the remaining tooth fragment migrates an average of 2 mm within two years. Conclusions Coronectomy is indicated when the mandibular third molar is in contact with the inferior alveolar nerve and complete removal of the tooth may cause nerve damage. Key words:Coronectomy, included third molar, inferior alveolar nerve injury. PMID:27031064

  17. [An 18 month evaluation of MM-MTA pulpotomy on primary decayed molars].

    PubMed

    Abou Chedid, J C; Mchayleh, N; Khalil, I; Melki, B; Hardan, L S

    2015-12-01

    Pulpotomy is the most performed and controversial therapeutic in pediatric dentistry. Formocresol is known to have a toxic effect on living tissues, a mutagenic and carcinogenic potential with a systemic uptake of formocresol via pulpotomized teeth, other alternative products have been investigated. 40 molars were pulpotomized using Micro Mega Mineral Trioxide Aggregate (MM-MTA), which eliminates the need for the use of formocresol. The effects of this material were evaluated both clinically and radiographically. Post-operative control examinations were performed at 1, 6, 12, and 18 months trying to detect spontaneous or stimulated pain, pathological tooth mobility, abscesses or fistulas, internal or external pathological tooth resorption, periapical bone destruction, or canal obliteration. Pain was absent at 18 months post operatively. Thirty six molar treated with the MM-MTA didn't show any mobility or pain, one molar presented a pathological resorption and one molar presented an abscess without a fistula at 12 month. The observations were compared to others related to formocresol, ferric sulfate, MTA, and laser pulpotomies, using the Chi-square test x2. The abundance of positive result strongly demonstrate that the MM-MTA pulpotomy on carious temporary molars is a promising technique. PMID:26939217

  18. Molar tooth structures in calcareous nodules, early Neoproterozoic Burovaya Formation, Turukhansk region, Siberia

    NASA Astrophysics Data System (ADS)

    Pope, Michael C.; Bartley, Julie K.; Knoll, Andrew H.; Petrov, Peter Yu.

    2003-05-01

    Molar tooth structures are abundant in large (1-2 m diameter) carbonate nodules within fine-grained, subtidal carbonates of the early Neoproterozoic (lower Upper Riphean) Burovaya Formation along the Sukhaya Tunguska River, Turukhansk Uplift, northwestern Siberia. Although molar tooth structures are regionally abundant in this unit, here they occur only within the nodules. Stable isotopic compositions of molar-tooth-filling dolomicrospar cements and of thinly bedded dolomicrite within and surrounding the nodules are indistinguishable from one another. The carbon isotopic compositions (mean δ13C=+2.8‰ PDB±0.4) reflect mean average oceanic surface water composition during their formation; the light oxygen isotopic compositions (mean δ18O=-6.4‰ PDB±2.2) are generally similar to those of other little-altered Meso- to Neoproterozoic limestones and dolostones. These molar tooth structures have no features that would support a tectonic origin; they more likely formed through bacterial processes. Carbonate cement filling of these voids occurred soon after their formation, but the mechanism responsible for this carbonate precipitation is currently uncertain. Local restriction of molar tooth structures to early diagenetic nodules suggests that penecontemporaneous lithification was required for the formation, or at least preservation, of these widespread Mesoproterozoic to Neoproterozoic features.

  19. Demirjian's method in the estimation of age: A study on human third molars

    PubMed Central

    Lewis, Amitha J.; Boaz, Karen; Nagesh, K. R; Srikant, N; Gupta, Neha; Nandita, K. P; Manaktala, Nidhi

    2015-01-01

    Aim: The primary aim of the following study is to estimate the chronological age based on the stages of third molar development following the eight stages (A to H) method of Demirjian et al. (along with two modifications-Orhan) and secondary aim is to compare third molar development with sex and age. Materials and Methods: The sample consisted of 115 orthopantomograms from South Indian subjects with known chronological age and gender. Multiple regression analysis was performed with chronological age as the dependable variable and third molar root development as independent variable. All the statistical analysis was performed using the SPSS 11.0 package (IBM ® Corporation). Results: Statistically no significant differences were found in third molar development between males and females. Depending on the available number of wisdom teeth in an individual, R2 varied for males from 0.21 to 0.48 and for females from 0.16 to 0.38. New equations were derived for estimating the chronological age. Conclusion: The chronological age of a South Indian individual between 14 and 22 years may be estimated based on the regression formulae. However, additional studies with a larger study population must be conducted to meet the need for population-based information on third molar development. PMID:26005306

  20. Morphologic and Demographic Predictors of Third Molar Agenesis: A Systematic Review and Meta-analysis.

    PubMed

    Carter, K; Worthington, S

    2015-07-01

    We aimed to consolidate all available data on worldwide third molar agenesis frequencies, with a particular emphasis on exploring the factors leading authors to find contradictory results for the demographic and morphologic predictors of this anomaly. A total of 12,376 studies were originally identified, then narrowed down to 1,312 for title/abstract screening. On the basis of our inclusion and exclusion criteria, we selected 92 studies, containing 100 effect sizes and 63,314 subjects, for systematic review and metaregression. The worldwide rate of agenesis was found to be 22.63% (95% confidence interval = 20.64% to 24.76%), although the estimates ranged from 5.32% to 56.0%. Our subgroup analyses revealed that women are 14% more likely than men to have agenesis of ≥1 third molars and that maxillary agenesis was 36% more likely than mandibular agenesis in both sexes. Furthermore, we found that having agenesis of 1 or 2 molars was most common, while agenesis of 3 or 4 molars was least common. Finally, we found large differences among agenesis frequency depending on geographic region. This information is expected to be of use not only to clinicians and patients but also to policy makers, given the implications for third molar extraction protocols. PMID:25883107

  1. Accuracy of scanography using storage phosphor plate systems and film for assessment of mandibular third molars

    PubMed Central

    Matzen, LH; Christensen, J; Wenzel, A

    2011-01-01

    Objectives The aim of this study was to compare the diagnostic accuracy of two digital photostimulable storage phosphor (PSP) systems and film for assessment of mandibular third molars before surgery. Methods 110 patients were referred to have both their mandibular third molars removed. Each patient underwent a radiographic examination with scanography using either Digora (Soredex, Helsinki, Finland) and film or VistaScan (Dürr Dental, Beitigheim-Bissingen, Germany) and film in a randomized paired design. Two observers examined the following variables on the scanograms: bone coverage, angulation of the tooth in the bone, number of roots, root morphology and the relationship to the mandibular canal. In 75 of the pairs (Digora/film pair = 38 and Vista/film pair = 37) both third molars were eventually removed. During and after surgery the same variables were assessed, which served as reference standard for the radiographic assessments. The Wilcoxon signed-rank test tested differences in accuracy (radiographic compared with surgical findings) between Digora/film and between Vista/film. Results There was no statistically significant difference between the diagnostic accuracy of film and either of the two digital receptors for assessment of mandibular third molars before surgery (P > 0.05), although Digora obtained a higher accuracy than film. Conclusions Scanography is a valuable method for examination of mandibular third molars before removal and the PSP digital receptors in this study were equal to film for this purpose. PMID:21697156

  2. The Diagnosis of Choriocarcinoma in Molar Pregnancies: A Revised Approach in Clinical Testing

    PubMed Central

    Duffy, Lisa; Zhang, Liangtao; Sheath, Karen; Love, Donald R.; George, Alice M.

    2015-01-01

    Background Hydatidiform moles occur in approximately 1 in 1,500 pregnancies; however, early miscarriages or spontaneous abortions may not be correctly identified as molar pregnancies due to poor differentiation of chorionic villi. Methods The current clinical testing algorithm used for the detection of hydatidiform moles uses a combination of morphological analysis and p57 immunostaining followed by ploidy testing to establish a diagnosis of either a complete or partial molar pregnancy. We review here 198 referrals for fluorescence in situ hybridization (FISH) ploidy testing, where the initial diagnosis based on morphology is compared to the final diagnosis based on a combination of morphology, FISH and p57 immunohistochemical (IHC) staining. Results Approximately 40% of cases were determined to be genetically abnormal, but only 28.8% of cases were diagnosed as molar pregnancies. The underestimation of complete molar pregnancies and those with androgenetic inheritance was also found to be likely using conventional diagnostic methods, as atypical p57 staining was observed in approximately 10% of cases. Conclusions Our findings suggest that a revised approach to testing products of conception is necessary, with cases screened according to their clinical history in order to distinguish molar pregnancy referrals from hydropic pregnancies. PMID:26566410

  3. Kissing molars: report of three cases and new prospective on aetiopathogenetic theories

    PubMed Central

    Menditti, Dardo; Laino, Luigi; Cicciù, Marco; Mezzogiorno, Antonio; Perillo, Letizia; Menditti, Marco; Cervino, Gabriele; Muzio, Lorenzo Lo; Baldi, Alfonso

    2015-01-01

    Kissing molars (KMs) is an extremely rare condition of impacted third molars, pointed in the opposite direction in a single follicular space; it consists exactly in a full impacted of permanent molars which occurs only in the lower jaw. Actually, about less than thirty cases have been reported in scientific literatures. The aetiology and pathogenesis of this pathological double dental inclusion remain unknown; above all events that lead two molars to appear, as KMs remain mysterious. The association to metabolic connective diseases such as mucopolysaccharidosis was emphasized. KMs considered as an isolated event, may be associated to an abnormal position of the tooth-bud from lower permanent molars, or fourth supernumerary tooth (distomolar). Recently, hyperplastic dental follicle (HDF), with a down regulation of matrix metal-proteinases and up regulation of several genes of collagens, has been mentioned in association with KMs. In this paper, after having analyzed three new cases of KMs that have been treated, we report a new hypothesis. This last is based on the failure in the dental follicle’s ability to initiate or continue properly resorption of the overlying alveolar bone, by many exogenous factors which may act on eruptive phase that would lead to its rotation with its contents coming out a pathological situation of KMs. The therapy of choice is related to the surgical removal of KMs through a double odontectomy with transalveolar method. Other treatments can be, eventually, orthodontic therapy of the impacted teeth and a radiological follow-up without surgery. PMID:26884840

  4. Anatomical study of C-shaped canals in mandibular second molars by analysis of computed tomography.

    PubMed

    Jin, Guang-Chun; Lee, Seong-Jong; Roh, Byoung-Duck

    2006-01-01

    The aim of this study was to investigate the prevalence and configuration of the C-shaped canal using serial axial computed tomography images of the mandibular second molars that had not been restored severely or treated endodontically, and to compare the thickness of the remaining tooth structure from the center of the canal to the outer surface of the deepest groove area in C-shaped mandibular second molar to that of "danger zone of perforation" in normal mandibular second molar. This distance was measured at the cervical, middle, and apical third level each. From 220 teeth, C-shaped canals were found in 98 teeth (44.5%). Almost all the grooves were directed lingual (99%). The continuous C-shaped canal was the most frequently found (49%) and the separated canal was the least (17.4%). The thinnest remaining tooth structure in the groove area of the C-shaped mandibular second molar was not different from that of the danger zone of normal mandibular second molar at the three levels (p > 0.05). PMID:16410060

  5. Displacement of lower third molar into the lateral pharyngeal space in a case of mandibular angle fracture: An unusual complication

    PubMed Central

    Kasatwar, Akash; Bhola, Nitin; Borle, Rajiv; Rajanikanth, K.

    2016-01-01

    Fracture of the angle of the mandible accounts for nearly one-third of all fractures involved. The presence of lower third molar increases the risk of fracture in angle region. The third molar acts as an area of weakness leading to fracture lines passing medially, distally, and occasionally through it. Angle fracture leads to the mobility of the third molar and sometimes its displacement. Third molars maintain its position in favorable fracture and can be displaced in unfavorable fractures. Displacement of lower third molar in lateral pharyngeal space due to mandibular fracture is not seen commonly. To our knowledge, this is the first reported incidence of displacement of the third molar into lateral pharyngeal space in a case of mandibular fracture. PMID:27307673

  6. Value of Computed Tomography (CT) in Imaging the Morbidity of Submerged Molars: A Case Report

    PubMed Central

    Kırzıoḡlu, Zuhal; Karayılmaz, Hüseyin; Baykal, Bahattin

    2007-01-01

    Submerged primary molars can be difficult to manage due to the developing dentition. Rarely in some severe cases, may the surgical interventions be required while ensuring the vital structures are protected. Therefore these cases require sophisticated imaging techniques in order to locate the vital structures. In this case report, a 17 year old girl who had a retained and submerged deciduous molar which caused impaction of the second premolar and tipping of the first molar was presented. In addition, value of computed tomography (CT) for locating the vital anatomic structures was discussed. In our case, CT has been supplied effective information about localization of the vital structures and amount of bone volume during the diagnosis and treatment planning period in addition to the routine dental radiographies. PMID:19212475

  7. Lingual nerve injury after third molar removal: Unilateral atrophy of fungiform papillae

    PubMed Central

    de-Pablo-Garcia-Cuenca, Alba; Bescós-Atín, Maria S.

    2014-01-01

    Background: Pain and sensory changes due to lingual nerve injury are one of the most common alterations that follow surgical removal of third molar. They are usually transient but other less common complications, such as the atrophy of fungiform papillae, have an uncertain prognosis. Case Description: We report a case of a 34-year-old woman who presented a unilateral lingual atrophy of fungiform papillae after third molar extraction accompanied by severe dysesthesia that altered her daily life significantly during the following months and how this complication evolved over time. We conducted a literature review on the different factors that can lead to a lingual nerve injury. Clinical Implications: The clinical evolution of temporary and permanent somatosensitve injuries is an important fact to take into consideration during the postoperative management because it will indicate the lesion prognosis. Key words:Lingual nerve, third molar removal, somatosensitive alteration, papillae atrophy, permanent injury, temporary injury. PMID:24790723

  8. Molar proportions of volatile fatty acids in the gastrointestinal tract of East African wild ruminants.

    PubMed

    Clemens, E T; Maloiy, G M; Sutton, J D

    1983-01-01

    The molar proportions of seven individual VFA's were determined at select sites along the gastrointestinal tract of sixteen species of East African wild ruminants. The resulting data were statistically analyzed for species effect, and for effects due to major feeding groups (browsers, grazers, fresh grass grazers, etc.) and for body weight groups (5-750 kg animals). Present data suggest that body weight, rather than diet, is the more influential factor in reticulo-rumen fermentation rate, and in the molar proportion of fatty acids present. The molar proportions of VFA's observed in the mid and hindgut of these wild ruminants appeared more responsive to diet and body weight of the animal than did foregut VFA values. PMID:6139202

  9. Holocellulose Nanofibers of High Molar Mass and Small Diameter for High-Strength Nanopaper.

    PubMed

    Galland, Sylvain; Berthold, Fredrik; Prakobna, Kasinee; Berglund, Lars A

    2015-08-10

    Wood cellulose nanofibers (CNFs) based on bleached pulp are different from the cellulose microfibrils in the plant cell wall in terms of larger diameter, lower cellulose molar mass, and modified cellulose topochemistry. Also, CNF isolation often requires high-energy mechanical disintegration. Here, a new type of CNFs is reported based on a mild peracetic acid delignification process for spruce and aspen fibers, followed by low-energy mechanical disintegration. Resulting CNFs are characterized with respect to geometry (AFM, TEM), molar mass (SEC), and polysaccharide composition. Cellulose nanopaper films are prepared by filtration and characterized by UV-vis spectrometry for optical transparency and uniaxial tensile tests. These CNFs are unique in terms of high molar mass and cellulose-hemicellulose core-shell structure. Furthermore, the corresponding nanopaper structures exhibit exceptionally high optical transparency and the highest mechanical properties reported for comparable CNF nanopaper structures. PMID:26151837

  10. Continuously growing rodent molars result from a predictable quantitative evolutionary change over 50 million years.

    PubMed

    Tapaltsyan, Vagan; Eronen, Jussi T; Lawing, A Michelle; Sharir, Amnon; Janis, Christine; Jernvall, Jukka; Klein, Ophir D

    2015-05-01

    The fossil record is widely informative about evolution, but fossils are not systematically used to study the evolution of stem-cell-driven renewal. Here, we examined evolution of the continuous growth (hypselodonty) of rodent molar teeth, which is fuelled by the presence of dental stem cells. We studied occurrences of 3,500 North American rodent fossils, ranging from 50 million years ago (mya) to 2 mya. We examined changes in molar height to determine whether evolution of hypselodonty shows distinct patterns in the fossil record, and we found that hypselodont taxa emerged through intermediate forms of increasing crown height. Next, we designed a Markov simulation model, which replicated molar height increases throughout the Cenozoic and, moreover, evolution of hypselodonty. Thus, by extension, the retention of the adult stem cell niche appears to be a predictable quantitative rather than a stochastic qualitative process. Our analyses predict that hypselodonty will eventually become the dominant phenotype. PMID:25921530

  11. Comment on ``Hydrophobic effects on partial molar volume'' [J. Chem. Phys. 122, 094509 (2005)

    NASA Astrophysics Data System (ADS)

    Graziano, Giuseppe

    2005-10-01

    It is pointed out that the results obtained by Imai and Hirata [ J. Chem. Phys.122, 094509 (2005)] for the partial molar volume of benzene in a detailed model of water and in a hypothetical nonpolar water model should be interpreted with care. By turning off the electrostatic interactions among water molecules, keeping fixed the molar volume and so the liquid number density, in order to produce the hypothetical nonpolar water without H bonds, the size of water molecules increases from about 2.8 to about 3.2Å. This fact is due to the bunching-up effect of H bonds. The consequences of this fact are clarified by means of calculations performed using the analytical expression of the partial molar volume derived by Lee [J. Phys. Chem.87, 112 (1983)] from the scaled particle theory equation of state for hard-sphere mixtures.

  12. Peri-operative concerns in a patient with thyroid storm secondary to molar pregnancy

    PubMed Central

    Samra, Tanvir; Kaur, Ranvinder; Sharma, Neha; Chaudhary, Lalita

    2015-01-01

    Awareness of the presence of thyroid function abnormalities in patients with molar pregnancy is important for its prompt diagnosis and management. We report the development of thyroid storm in the immediate post-operative period in a 25-year-old female who underwent evacuation of her molar pregnancy under saddle spinal block after being controlled for her thyrotoxicosis with a combination of antithyroid drugs, iodine, steroids and adrenergic blocking agents. We advocate the use of esmolol infusions up to a maximum dose of 200 μg/kg/min for immediate haemodynamic management of the patient. Optimum time needed for stabilisation of the hyper metabolic state after initiation of antithyroid drugs is still not known and evacuation of molar pregnancy remains the only definitive management of the thyrotoxic state. PMID:26755840

  13. Survival and success rate of one-piece implant inserted in molar sites

    PubMed Central

    Carinci, Francesco

    2012-01-01

    Background: Recently, the use of one-piece implants (OPI) has become more popular. Since no reports specifically focus on OPIs inserted in molar areas, a retrospective study has been performed. Materials and Methods: A series of 36 OPIs (Diamond; BIOIMPLANT, Milan, Italy) were inserted into the molar area of patients admitted at the Dental Clinic, University of Chieti, Italy, for oral rehabilitation between January and December 2010. Results: In our series survival rate (SVR) and success rate (SCR) were 91.7% and 97%, respectively. Statistical analysis demonstrated that no studied variable has an impact on survival (i.e., lost implants) as well as on clinical success (i.e., crestal bone resorption). Conclusion: OPIs are reliable devices for oral rehabilitation in the molar areas. PMID:23814575

  14. Peri-operative concerns in a patient with thyroid storm secondary to molar pregnancy.

    PubMed

    Samra, Tanvir; Kaur, Ranvinder; Sharma, Neha; Chaudhary, Lalita

    2015-11-01

    Awareness of the presence of thyroid function abnormalities in patients with molar pregnancy is important for its prompt diagnosis and management. We report the development of thyroid storm in the immediate post-operative period in a 25-year-old female who underwent evacuation of her molar pregnancy under saddle spinal block after being controlled for her thyrotoxicosis with a combination of antithyroid drugs, iodine, steroids and adrenergic blocking agents. We advocate the use of esmolol infusions up to a maximum dose of 200 μg/kg/min for immediate haemodynamic management of the patient. Optimum time needed for stabilisation of the hyper metabolic state after initiation of antithyroid drugs is still not known and evacuation of molar pregnancy remains the only definitive management of the thyrotoxic state. PMID:26755840

  15. Correlating molar masses of nitrocelluloses with their intrinsic viscosities measured using capillary electrophoresis instrumentation.

    PubMed

    Alinat, Elodie; Delaunay, Nathalie; Archer, Xavier; Gareil, Pierre

    2015-09-01

    Specific viscosities for a set of six nitrocellulose (NC) standards comprising three different mass-average molar masses (between 20,000 and 300,000 g mol(-1)) of two different nitrogen contents (11.2 and 12.1%) were measured at 20 °C in tetrahydrofuran, using capillary electrophoresis instrumentation as a bench-top viscometer in frontal mode. Intrinsic viscosities were derived applying Huggins' and Kraemer's models, showing excellent convergence of both models at infinitely diluted polymer concentration. Good overall consistency was shown between viscosity data experimentally acquired by this new protocol and the mass-average molar masses provided by the manufacturers. This simple protocol should be of interest for a better understanding of the solvent interaction given by this complex polymer, and beyond this, for tailoring NC solutions devoted to film deposition, and for the determination of mass-average molar masses of unknown NC samples. PMID:26005144

  16. Estimation of molar absorptivities and pigment sizes for eumelanin and pheomelanin using femtosecond transient absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Piletic, Ivan R.; Matthews, Thomas E.; Warren, Warren S.

    2009-11-01

    Fundamental optical and structural properties of melanins are not well understood due to their poor solubility characteristics and the chemical disorder present during biomolecular synthesis. We apply nonlinear transient absorption spectroscopy to quantify molar absorptivities for eumelanin and pheomelanin and thereby get an estimate for their average pigment sizes. We determine that pheomelanin exhibits a larger molar absorptivity at near IR wavelengths (750nm), which may be extended to shorter wavelengths. Using the molar absorptivities, we estimate that melanin pigments contain ˜46 and 28 monomer units for eumelanin and pheomelanin, respectively. This is considerably larger than the oligomeric species that have been recently proposed to account for the absorption spectrum of eumelanin and illustrates that larger pigments comprise a significant fraction of the pigment distribution.

  17. An Evaluation of Pathologic Changes in the Follicle of Impacted Mandibular Third Molars

    PubMed Central

    Tambuwala, Aruna Azhar; Oswal, Rakesh Gulabchand; Desale, Rushikesh Suresh; Oswal, Nitin Prakash; Mall, Prashant Edwin; Sayed, Aatif Riyaz; Pujari, Aniket Tarachand

    2015-01-01

    Background: The purpose of this study was to evaluate the early pathologic changes in the follicular tissue of completely impacted mandibular third molar. Materials and Methods: 52 patients, between 18 and 52 years of age of which 25 were males and 27 were females, were selected. They had impacted mandibular third molars, which were indicated for extraction. After extraction, the follicle was sent for a histopathological evaluation to two different oral pathologists. Results: The results showed that 80.8% of the specimen had normal follicles. 11.5% specimen suggested cystic changes while 7.7% suggested infected follicle. Conclusion: It is desirable to consider prophylactic removal of impacted mandibular third molar presenting at a younger age, whereas their removal remains an enigma for the older age group and should only be considered appropriate in those cases where frank causes for its removal are established. PMID:25954073

  18. Analysis of masseter and temporal muscles during surgical extraction of impacted third molars.

    PubMed

    Moraes, Michelle B; Naclerio-Homem, Maria G; Nascimento, Rodrigo D; Oliveira Amorim, Jose Benedito; Raldi, Fernando V

    2015-01-01

    With the aim of contributing to the discussion on stomatognathic system dysfunction after surgical procedures, this study compared the electromyographic activity of the superficial masseter and temporal masticatory muscles before, during, and after impacted mandibular third molar extractions. Muscular activity was recorded presurgery, transsurgery, immediately postoperatively, and on postoperative days 7, 15, and 30. Twenty patients requiring extraction of impacted mandibular third molars were selected and evaluated. In 20 patients who underwent mandibular third molar extractions, electromyography showed no alterations in muscle tone, and no statistically significant differences were observed in the left and right temporal and masseter muscles at any of the experimental periods at either mandibular rest or isometric contraction position. However, the degree of mouth opening increased 11.76% from pretreatment to 30 days after surgery. These results may reflect the shorter, careful extraction procedure performed by the surgeon. PMID:26325653

  19. Risks and benefits of removal of impacted third molars. A critical review of the literature.

    PubMed

    Mercier, P; Precious, D

    1992-02-01

    A critical review of the literature about risks and benefits of the removal of impacted 3rd molar teeth is presented in 4 categories: risk of non-intervention, risk of intervention, benefit of non-intervention and benefit of intervention. There are well-defined criteria for removal of impacted 3rd molar teeth. Absolute indications and contra-indications for the removal of asymptomatic 3rd molar teeth cannot be established because no long-term studies exist which validate the benefit to the patient either of early removal or of deliberate retention of these teeth. The prudent course of action for the clinician to follow is based on rational clinical decision-making using traditional methods of evaluation to effect the optimal outcome, keeping the interests of the individual patient above all else. PMID:1569360

  20. Endodontic management of mandibular first molar with seven canals using cone-beam computed tomography

    PubMed Central

    Banode, Ankur Mahesh; Gade, Vandana; Patil, Sanjay; Gade, Jaykumar

    2016-01-01

    The endodontic treatment of a mandibular molar with aberrant canal configuration can be diagnostically and clinically challenging. Successful endodontic therapy thus depends on the clinician's ability to anticipate and look for these aberrant variations. A mandibular first molar with seven canals represents a rare anatomical variant, particularly when four canals are found in distal root. Based on in vitro studies, its incidence is reported to be between 0.2% and 3%. With the advent of cone-beam computed tomography (CBCT) as an adjunctive diagnostic aid, the determination of root canal anatomy in teeth with complex canal configurations has become more precise. The present case report discusses successful nonsurgical management of radix entomolaris along with middle mesial canal and middle distal canal in mandibular first molar with seven canals (four canals in distal and three in mesial) employing CBCT as an adjunctive diagnostic aid to conventional radiography. PMID:27307680

  1. Long-term Stability of Autotransplanted Premolars as a Substitute for Molars in Adults.

    PubMed

    Kim, Sunil; Shin, Su-Jung; Park, Jeong-Won; Kim, Sunjai; Hwang, Soonshin; Kim, Kyung-Ho; Chung, Chooryung J

    2016-08-01

    Autotransplantation is a viable treatment option for tooth replacement when a suitable donor tooth is available. This case report presents 2 cases that describe successful treatment outcome and prognosis after autotransplantation of a mature premolar as a missing molar. The first premolar was extracted for orthodontic purposes and transplanted to the missing first molar site in the mandible. The transplanted tooth was monitored up to 7 years. The transplant was functional and maintained a normal bone level throughout the follow-up period. Clinical examination showed normal physiologic movement without any signs of ankylosis and root resorption. Autotransplantation of a mature premolar to a molar site is a viable treatment option showing successful results. The selection of a functional donor tooth, adequate surgical procedures, and timely application of orthodontic movement may have positively contributed to the favorable prognosis. PMID:27374818

  2. Continuously growing rodent molars result from a predictable quantitative evolutionary change over 50 million years

    PubMed Central

    Mushegyan, Vagan; Eronen, Jussi T.; Lawing, A. Michelle; Sharir, Amnon; Janis, Christine; Jernvall, Jukka; Klein, Ophir D.

    2015-01-01

    Summary The fossil record is widely informative about evolution, but fossils are not systematically used to study the evolution of stem cell-driven renewal. Here, we examined evolution of the continuous growth (hypselodonty) of rodent molar teeth, which is fuelled by the presence of dental stem cells. We studied occurrences of 3500 North American rodent fossils, ranging from 50 million years ago (mya) to 2 mya. We examined changes in molar height to determine if evolution of hypselodonty shows distinct patterns in the fossil record, and we found that hypselodont taxa emerged through intermediate forms of increasing crown height. Next, we designed a Markov simulation model, which replicated molar height increases throughout the Cenozoic, and, moreover, evolution of hypselodonty. Thus, by extension, the retention of the adult stem-cell niche appears to be a predictable quantitative rather than a stochastic qualitative process. Our analyses predict that hypselodonty will eventually become the dominant phenotype. PMID:25921530

  3. Endodontic management of mandibular first molar with seven canals using cone-beam computed tomography.

    PubMed

    Banode, Ankur Mahesh; Gade, Vandana; Patil, Sanjay; Gade, Jaykumar

    2016-01-01

    The endodontic treatment of a mandibular molar with aberrant canal configuration can be diagnostically and clinically challenging. Successful endodontic therapy thus depends on the clinician's ability to anticipate and look for these aberrant variations. A mandibular first molar with seven canals represents a rare anatomical variant, particularly when four canals are found in distal root. Based on in vitro studies, its incidence is reported to be between 0.2% and 3%. With the advent of cone-beam computed tomography (CBCT) as an adjunctive diagnostic aid, the determination of root canal anatomy in teeth with complex canal configurations has become more precise. The present case report discusses successful nonsurgical management of radix entomolaris along with middle mesial canal and middle distal canal in mandibular first molar with seven canals (four canals in distal and three in mesial) employing CBCT as an adjunctive diagnostic aid to conventional radiography. PMID:27307680

  4. Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect.

    PubMed

    Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

    2014-11-26

    The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. PMID:25256478

  5. Classification of impacted mandibular third molars on cone-beam CT images

    PubMed Central

    Maglione, Michele; Bazzocchi, Gabriele

    2015-01-01

    Background Neurological involvement is a serious complication associated to the surgical removal of impacted mandibular third molars and the radiological investigation is the first mandatory step to assess the risk of a possible post-operative injury to the inferior alveolar nerve (IAN). The aim of this study was to introduce a new radiological classification that could be normally used in clinical practice to assess the relationship between an impacted third molar and mandibular canal on cone beam CT (CBCT) images. Material and Methods CBCT images of 80 patients (133 mandibular third molars) were independently studied by three members of the surgical team to draw a classification that could describe all the possible relationships between third molar and IAN on the cross-sectional images. Subsequently, the study population was subdivided according to this classification. The SPSS software, version 15.0 (SPSS® Inc., Chicago, Illinois, USA) was used for the statistical analysis. Results Eight different classes were proposed (classes 0-7) and six of them (classes 1-6) were subdivided in two subtypes (subtypes A-B). The distribution of classes showed a prevalence of buccal or apical course of the mandibular canal followed by lingual position and inter-radicular one. No differences have resulted in terms of anatomic relationship between males and females apart from a higher risk of real contact without corticalization of the canal when the IAN had a lingual course for female group. Younger patients showed an increased rate of direct contact with a reduced calibre of the canal and/or without corticalization. Conclusions The use of this classification could be a valid support in clinical practice to obtain a common language among operators in order to define the possible relationships between an impacted third molar and the mandibular canal on CBCT images. Key words:CBCT, classification, inferior alveolar nerve, third molars. PMID:26155337

  6. Efficacy of the technique of piezoelectric corticotomy for orthodontic traction of impacted mandibular third molars.

    PubMed

    Ma, Zhigui; Xu, Guangzhou; Yang, Chi; Xie, Qianyang; Shen, Yuqing; Zhang, Shanyong

    2015-04-01

    Our aim was to assess the efficacy of piezoelectric corticotomy for orthodontic traction of mandibular third molars close to the inferior alveolar nerve. Thirty patients with impacted third molars close to the nerve were included in the study, 15 of whom were treated with conventional orthodontic traction and 15 with piezoelectric corticotomy. We recorded duration of treatment including exposure and orthodontic traction, and time to the final extraction. Postoperative complications including trismus, swelling, and pain were also noted. Alveolar bone levels mesial and distal to the second molars were evaluated on cone-beam computed tomographic (CT) images. Student's t test was used to assess the significance of differences between the groups. After orthodontic treatments all impacted third molars were successfully removed from the inferior alveolar nerve without neurological damage. The mean (SD) duration of surgical exposure in the piezoelectric corticotomy group was significantly longer than that in the conventional group (p=0.01). The mean (SD) duration of traction was 4 (2.3) months after piezoelectric corticotomy, much shorter than the 7.5 (1.3) months in the conventional group (p=0.03). There were no significant differences in postoperative complications between the groups. There was a significant increase in the distal alveolar height of second molars after treatment in both groups (p<0.01). We conclude that the use of piezoelectric corticotomy allows more efficient and faster traction of third molars with a close relation between the root and the inferior alveolar nerve, although it took longer than the traditional technique. PMID:25638568

  7. Prevention of localized osteitis in mandibular third-molar sites using platelet-rich fibrin.

    PubMed

    Hoaglin, Donald R; Lines, Gary K

    2013-01-01

    Purpose. To review our experience utilizing platelet rich fibrin (PRF), which is reported to aid in wound healing of extraction sites, for the prevention of localized osteitis following lower third-molar removal. Materials and Methods. PRF was placed in the mandibular third-molar extraction sites, 200 sites total, on 100 consecutive patients treated in our practice, by the authors. The patients were managed with standard surgical techniques, intraoperative IV antibiotic/steroid coverage, and routine postoperative narcotic analgesics/short-term steroid coverage. All patients were reevaluated for localized osteitis within 7-10 days of the surgery. A comparison group consisted of 100 consecutive patients who underwent bilateral removal of indicated mandibular wisdom teeth and did not receive PRF placement within the lower third molar surgical sites. Results. The incidence of localized osteitis (LO) following removal of 200 lower third molars with simultaneous PRF placement within the extraction site was 1% (2 sites out of 200). The group of patients whose mandibular 3rd molar sockets were not treated with PRF demonstrated a 9.5% (19 sites out of 200) incidence of localized osteitis. The latter group also required 6.5 hours of additional clinical time to manage LO than the study group who received PRF. Conclusions. This retrospective review demonstrated that preventative treatment of localized osteitis can be accomplished using a low cost, autogenous, soluble, biologic material, PRF, that PRF enhanced third-molar socket healing/clot retention and greatly decreased the clinical time required for postoperative management of LO. PMID:23653648

  8. [An unusual jugal abscess after third molar extraction: a complication of hemostatic wax].

    PubMed

    Brignol, L; Guyot, L; Richard, O; Chossegros, C

    2007-04-01

    Bleeding is a common complication after third molar extraction. Hemostatic agents can be helpful in controlling intraoperative bleeding. Infection is another common complication. Horseley's wax is frequently used for bone surgery and less often for dental surgery. We report an unusual case of abscess formation in the jaw after third molar extraction. Surgical exploration of the abscess disclosed the presence of surgical wax in the center of a foreign body granuloma. We discuss the use of surgical wax and other local hemostatic agents and the subsequent risk of complications. PMID:17350058

  9. A monitoring and evaluation study of third molar surgery complications at a major medical center.

    PubMed

    Herpy, A K; Goupil, M T

    1991-01-01

    This monitoring and evaluation study of third molar surgery complications took place over a 6-month period of time. The goal of the study was to determine complication rates following third molar extraction. A comparison was made between the staff's and residents' post-operative complication rates and patients receiving tetracycline powder in the extraction sockets vs. no antibiotics. Complication rates were compared in males vs. females, and in four different age groups. The study helped improve patient care by showing that alveolar osteitis rates decreased when all patients received topical tetracycline. It also confirmed that the experience of the surgeon, patient age, and gender influence complication rates. PMID:1900107

  10. [Radiographic and histological study of a case of apexification in a human molar].

    PubMed

    Sahli, C C

    1989-01-01

    A case of apexification in a lower right second molar is described. Radiographs demonstrate apical closure with a different morphological pattern from that of the lower left second molar. Following extraction, after 15 months, serial histologic sections show calcified tissue obturating the apical foramen, well adapted to the initial dentin and cementum walls. Inside some small areas containing connective tissue with capillaries can be observed. The histologic and radiographic observations indicate that apical closure occurs as a result of differentiation of periodontal apical cells. PMID:2640033

  11. Coronectomy of mandibular teeth other than third molars: a case series.

    PubMed

    Samani, Meera; Henien, Marianne; Sproat, Christopher

    2016-09-01

    Coronectomy is gaining popularity for the management of mandibular third molars that pose a risk of injury to the inferior dental nerve, as it considerably reduces the risk when compared with extraction. The technique could also be beneficial to other teeth. We report 17 patients who had coronectomy of mandibular teeth that were not third molars. Clinical and radiographic follow up for a median (range) of 12 (1-79) months showed satisfactory healing and no transient or permanent injury to the nerve. None of the retained roots have required retrieval. PMID:27256801

  12. Paramolar – A supernumerary molar: A case report and an overview

    PubMed Central

    Nayak, Gurudutt; Shetty, Shashit; Singh, Inderpreet; Pitalia, Deepti

    2012-01-01

    Paramolar is a supernumerary molar usually small and rudimentary, most commonly situated buccally or palatally to one of the maxillary molars. Paramolar is a developmental anomaly and has been argued to arise from a combination of genetic and environmental factors. Reports of this entity are rarely found in the dental literature. This article presents a case report of an unusual occurrence of a paramolar in the maxilla in otherwise a healthy individual. In addition, literature review, prevalence, classification, etiology, complications, diagnosis, and therapeutic strategies that may be adopted when supernumeraries occurs have been discussed. PMID:23559961

  13. Management of Grossly Decayed Mandibular Molar with Different Designs of Split Cast Post and Core

    PubMed Central

    Bansal, Rashmi; Mehrotra, Nakul; Chowdhary, Priyanka; Gurtu, Anuraag

    2016-01-01

    Mandibular molar with extensive loss of tooth structure, especially where no cavity wall is remaining, and insertion of posts in both the roots appear necessary so as to achieve proper retention for the core material. A single unit metal casting with two posts, one in the mesial root and the other in the distal divergent root, is difficult to fabricate due to difference in the path of insertion of the two posts. Multisection post and core or single cast post and core with auxiliary post can be an effective design to manage grossly decayed mandibular molars. PMID:27144038

  14. Modified lingual split technique for extraction of impacted mandibular third molars.

    PubMed

    Lewis, J E

    1980-08-01

    Critical evaluation of existing chisel and bur techniques for removal of impacted mandibular third molars reveals a high incidence of complications. Both approaches require creation of a buccal defect immediately distal to the second molar for the insertion of an elevator, which may cause pocketing to occur postoperatively. The method described here minimizes periosteal reflection, almost completely avoids loss of bone, and effectively reduces the use of rotary instrumentation. The planning of the soft tissue flaps and bony cuts assists in primary wound closure, obliteration of dead space, and reduction of postoperative morbidity. PMID:6930459

  15. The magnitude of a human bite measured exactly at the molar Intercuspidation using FBG

    NASA Astrophysics Data System (ADS)

    Marin, Gabriela Costa; Milczewski, Maura S.; Abe, Ilda; Lopes, Stephani C. P. S.; Camargo, Elisa S.; Kalinowski, Hypolito J.

    2014-05-01

    The aim of the study is to develop a new punctual method to determine the human bite force, between uppers and lowers first molars, at the moment of occlusion in maximum intercuspation. Fibre optic Bragg gratings are encapsulated in an acetate splint made by casting of a volunteer lower dentition. Splint sensor was positioned into the mouth to be pressured with minimal occlusal interference. The transversal pressure on the FBG was acquired at the moment of before occlusion (free), occlusion and biting. The measured forces were 12N during occlusion and 28N bite force, between right uppers and lowers first molars.

  16. Pseudo-critical behavior on the partial molar volume of solutes in the isotropic phase of liquid crystal

    NASA Astrophysics Data System (ADS)

    Matsuoka, Tatsuro; Nakamura, Shunsuke; Yamaguchi, Tsuyoshi; Koda, Shinobu

    2012-01-01

    Temperature dependence of partial molar volume of 4-amino-4‧-nitrobiphenyl (ANB) and 4,4‧-dinitrobiphenyl (DNB) in the isotropic phase of 4-n-pentyl-4‧-cyanobiphenyl (5CB) was determined. Addition of ANB to 5CB causes increase of isotropic-nematic phase transition temperature (TIN) [1]. The decrease of partial molar volume of ANB was observed while the increase of partial molar volume of DNB and triphenyl phosphite (TPP) [8] was observed with approaching TIN. The anomalous behavior of partial molar volume was discussed using treatments similar to that of other thermodynamic derivatives in the I-N transition.

  17. Evaluation of skeletal maturation using mandibular third molar development in Indian adolescents

    PubMed Central

    Mehta, Nishit; Patel, Dolly; Mehta, Falguni; Gupta, Bhaskar; Zaveri, Grishma; Shah, Unnati

    2016-01-01

    Objective: This study was done with the following objectives: to estimate dental maturity using the Demirjian Index (DI) for the mandibular third molar; to investigate the relationship between dental maturity and skeletal maturity among growing patients; to evaluate the use of the mandibular third molar as an adjunctive tool for adolescent growth assessment in combination with the cervical vertebrae; to evaluate the clinical value of the third molar as a growth evaluation index. Materials and Methods: Samples were derived from panoramic radiographs and lateral cephalograms of 615 subjects (300 males and 315 females) of ages ranging 9-18 years, and estimates of dental maturity (DI) and skeletal maturity [cervical vertebrae maturation indicators (CVMI)] were made. Results: A highly significant association (r = 0.81 for males and r = 0.72 for females) was found between DI and CVMI. DI Stage B corresponded to Stage 2 of CVMI (prepeak of pubertal growth spurt) in both sexes. In males, DI stages C and D represent the peak of the pubertal growth spurt. In females, stages B and C show that the peak of the pubertal growth spurt has not been passed. DI stage E in females and DI Stage F in males correlate that the peak of the pubertal growth spurt has been passed. Conclusion: A highly significant association exists between DI and CVMI. Mandibular third molar DI stages are reliable adjunctive indicators of skeletal maturity. PMID:27555733

  18. Determination of the Molar Volume of Hydrogen from the Metal-Acid Reaction: An Experimental Alternative.

    ERIC Educational Resources Information Center

    de Berg, Kevin; Chapman, Ken

    1996-01-01

    Describes an alternative technique for determining the molar volume of hydrogen from the metal-acid reaction in which the metal sample is encased in a specially prepared cage and a pipette filler is used to fill an inverted burette with water. Eliminates some difficulties encountered with the conventional technique. (JRH)

  19. Prediction of postoperative facial swelling, pain and trismus following third molar surgery based on preoperative variables

    PubMed Central

    de Souza-Santos, Jadson A.; Martins-Filho, Paulo R.; da Silva, Luiz C.; de Oliveira e Silva, Emanuel D.; Gomes, Ana C.

    2013-01-01

    Objective: This paper investigates the relationship between preoperative findings and short-term outcome in third molar surgery. Study design: A prospective study was carried out involving 80 patients who required 160 surgical extractions of impacted mandibular third molars between January 2009 and December 2010. All extractions were performed under local anesthesia by the same dental surgeon. Swelling and maximal inter-incisor distance were measured at 48 h and on the 7th day postoperatively. Mean visual analogue pain scores were determined at four different time periods. Results: One-hundred eight (67.5%) of the 160 extractions were performed on male subjects and 52 (32.5%) were performed on female subjects. Median age was 22.46 years. The amount of facial swelling varied depending on gender and operating time. Trismus varied depending on gender, operating time and tooth sectioning. The influence of age, gender and operating time varied depending on the pain evaluation period (p < 0.05). Conclusions: Short-term outcomes of third molar operations (swelling, trismus and pain) differ depending on the patients’ characteristics (age, gender and body mass index). Moreover, surgery characteristics such as operating time and tooth sectioning were also associated with postoperative variables. Key words:Third molar extraction, pain, swelling, trismus, postoperative findings, prediction. PMID:23229245

  20. Morphological measurements of anatomic landmarks in human maxillary and mandibular molar pulp chambers.

    PubMed

    Deutsch, Allan S; Musikant, Barry Lee

    2004-06-01

    The aim of this in vitro study was to measure critical morphology of molar pulp chambers. One hundred random human maxillary and mandibular molars (200 teeth in total) were used. Each molar was radiographed mesiodistally on a millimeter grid. Using a stereomicroscope, the measurements were read to the nearest 0.5 mm. Results were as follows (mean, mm): pulp chamber floor to furcation, maxillary = 3.05 +/- 0.79, mandibular = 2.96 +/- 0.78; pulp chamber ceiling to furcation, maxillary = 4.91 +/- 1.06, mandibular = 4.55 +/- 0.91; buccal cusp to furcation, maxillary = 11.15 +/- 1.21, mandibular = 10.90 +/- 1.21; buccal cusp to pulp chamber floor, maxillary = 8.08 +/- 0.88, mandibular = 7.95 +/- 0.79; buccal cusp to pulp chamber ceiling, maxillary = 6.24 +/- 0.88, mandibular = 6.36 +/- 0.93; and pulp chamber height, maxillary = 1.88 +/- 0.69, mandibular = 1.57 +/- 0.68. The pulp chamber ceiling was at the level of the cementoenamel junction in maxillary, 98%, and mandibular, 97% of the specimens. The measurements showing the lowest percentage variance were buccal cusp to furcation (approximately 11%) and buccal cusp to pulp chamber ceiling (approximately 14%). The measurements were similar for both maxillary and mandibular molars. PMID:15167463

  1. Parasymphyseal fracture associated with fracture of a maxillary primary molar in a child: case report.

    PubMed

    Abdelnur, Juliana Pires; da Rosa Götze, Gabriela; Barreira, Alice Kelly; Maia, Lucianne Cople

    2009-04-01

    Bone and posterior tooth fractures can be serious injuries that are difficult to diagnose, particularly in emergencies. The aim of this study was to report a case of a parasymphyseal fracture associated with the fracture of a maxillary primary molar in a child. PMID:19290889

  2. Ovarian Malignant Mixed Germ Cell Tumor: A Case of Unusual Presentation as Molar Pregnancy

    PubMed Central

    Aminimoghaddam, Soheila; Mohseni, Iman; Afzalzadeh, Azadeh; Esmaeeli, Shooka

    2016-01-01

    Background: This research was conducted to introduce a patient with rare ovarian mixed germ cell tumor, presented as molar pregnancy. Case Presentation: The patient was a 16 year old woman admitted with diagnosis of molar pregnancy. Abdominal enlargement was the only complaint. She had a large pelvic mass in physical examination. The first diagnosis was molar pregnancy due to previous ultrasonic reports and positive βeta HCG. Urine pregnancy test was positive. As suction curettage was performed for her, surprisingly, the size of uterus was normal and no molar tissue was found in pathologic examination. At intraoperative ultrasound exam, an extra-uterine heterogeneous mass was found. Extra-uterine mass was confirmed by CT and MRI done after suction curettage. Mixed germ cell tumor was confirmed by histological examination after laparatomy and removing tumoral mass. Finally, she received Bleomycin, Etoposide and Cisplatin (BEP) regimen in four courses and Vincristine, Actinomycin D (Dactinomycin) and Cyclophosphamide (VAC) regimen in two courses and Diphereline for saving the other ovary. Conclusion: Some young patients misinterpret the early symptoms of an ovarian neoplasm as those of pregnancy which can lead to a delay in the diagnosis. PMID:27141469

  3. Three-dimensional molar enamel distribution and thickness in Australopithecus and Paranthropus.

    PubMed

    Olejniczak, A J; Smith, T M; Skinner, M M; Grine, F E; Feeney, R N M; Thackeray, J F; Hublin, J-J

    2008-08-23

    Thick molar enamel is among the few diagnostic characters of hominins which are measurable in fossil specimens. Despite a long history of study and characterization of Paranthropus molars as relatively 'hyper-thick', only a few tooth fragments and controlled planes of section (designed to be proxies of whole-crown thickness) have been measured. Here, we measure molar enamel thickness in Australopithecus africanus and Paranthropus robustus using accurate microtomographic methods, recording the whole-crown distribution of enamel. Both taxa have relatively thick enamel, but are thinner than previously characterized based on two-dimensional measurements. Three-dimensional measurements show that P. robustus enamel is not hyper-thick, and A. africanus enamel is relatively thinner than that of recent humans. Interspecific differences in the whole-crown distribution of enamel thickness influence cross-sectional measurements such that enamel thickness is exaggerated in two-dimensional sections of A. africanus and P. robustus molars. As such, two-dimensional enamel thickness measurements in australopiths are not reliable proxies for the three-dimensional data they are meant to represent. The three-dimensional distribution of enamel thickness shows different patterns among species, and is more useful for the interpretation of functional adaptations than single summary measures of enamel thickness. PMID:18522924

  4. 40 CFR 1066.610 - Mass-based and molar-based exhaust emission calculations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... specified in 40 CFR 86.144 or 40 CFR part 1065, subpart G. (b) For composite emission calculations over... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Mass-based and molar-based exhaust... (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Calculations § 1066.610 Mass-based and...

  5. 40 CFR 1066.610 - Mass-based and molar-based exhaust emission calculations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specified in 40 CFR 86.144 or 40 CFR part 1065, subpart G. (b) For composite emission calculations over... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Mass-based and molar-based exhaust... (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Calculations § 1066.610 Mass-based and...

  6. Differential Evolvability Along Lines of Least Resistance of Upper and Lower Molars in Island House Mice

    PubMed Central

    Renaud, Sabrina; Pantalacci, Sophie; Auffray, Jean-Christophe

    2011-01-01

    Variation within a population is a key feature in evolution, because it can increase or impede response to selection, depending on whether or not the intrapopulational variance is correlated to the change under selection. Hence, main directions of genetic variance have been proposed to constitute “lines of least resistance to evolution” along which evolution would be facilitated. Yet, the screening of selection occurs at the phenotypic level, and the phenotypic variance is not only the product of the underlying genetic variance, but also of developmental processes. It is thus a key issue for interpreting short and long term evolutionary patterns to identify whether main directions of phenotypic variance indeed constitute direction of facilitated evolution, and whether this is favored by developmental processes preferably generating certain phenotypes. We tackled these questions by a morphometric quantification of the directions of variance, compared to the direction of evolution of the first upper and lower molars of wild continental and insular house mice. The main phenotypic variance indeed appeared as channeling evolution between populations. The upper molar emerged as highly evolvable, because a strong allometric component contributed to its variance. This allometric relationship drove a repeated but independent evolution of a peculiar upper molar shape whenever size increased. This repeated evolution, together with knowledge about the molar development, suggest that the main direction of phenotypic variance correspond here to a “line of least developmental resistance” along which evolution between population is channeled. PMID:21589657

  7. Biodiesel from Canola Oil using a 1:1 Molar Mixture of Methanol and Ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canola oil was transesterified using an equimolar mixture of ethanol and methanol with potassium hydroxide (KOH) catalyst. Effect of catalyst concentration (0.5 to 1.5% wt/wt), molar ratio of equimolar mixture of ethanol and methanol (EMEM) to canola oil (3:1 to 12:1) and reaction temperature (25 t...

  8. Maxillary molar distalization with MGBM-system in class II malocclusion

    PubMed Central

    Maino, Giuliano; Mariani, Lisa; Bozzo, Ida; Maino, Giovanna; Caprioglio, Alberto

    2013-01-01

    Aims: Objective of this retrospective study was to evaluate the treatment effects of the MGBM-System (G.B Maino, A. Giannelly, R. Bernard, P. Mura), a new intraoral device to treat Class II malocclusions Materials and Methods: A retrospective study was conducted to compare the pre-distalization and post-distalization cephalograms and dental model casts of 30 patients (15 male, 15 female) with Class II malocclusion treated with MGBM-System. Mean age at the beginning of treatment was 13.3 years (standard deviation 3.3). Angular, horizontal and vertical measurements were recorded to monitor skeletal and dental-alveolar changes. Molar movements in horizontal plane were monitored by making dental measurements on dental model casts. Results: The MGBM-System produced a rapid molar distalization and Class II relationship was corrected in 8 months ± 2.05, on average. The maxillary first molars were distalized of 4.14 (PTV-6 cemento-enamel junction), associated with a significant distal axis incline of 10. 5° referred to SN and a significant intrusion of 1.3 mm (PP). As for anchorage loss, the first premolar exhibited a significant mesial movement of 0.86 mm, associated with a significant mesial axis incline of 2.46°. No significative changes in either sagittal or vertical skeletal relationship were observed. Conclusion: The results suggest that the MGBM-System is an efficient and reliable device for distalizing the maxillary permanent first and second molars. PMID:24987649

  9. Ovulation stimulation after treatment for a molar pregnancy for or against?

    PubMed

    Gojnic, M; Dugalic, V; Brankovic, M; Pervulov, M; Vasiljevic, B; Fazlagic, A

    2009-01-01

    The case of a 29-year-old patient who underwent invitro fertilization due to secondary sterility, after a spontaneous but molar pregnancy, is described. Afterwards there was no spontaneous conception for five years. With the couple's consent, we decided to perform in vitro fertilization, i.e., ovulation induction and the ICSI (intracytoplasmic sperm injection) method. PMID:19317269

  10. Endodontic management of a mandibular second molar with radix entomolaris: a case report

    PubMed Central

    Kandaswamy, Deivanayagam; Jayaprakash, Nachimuthu

    2014-01-01

    The presence of radix entomolaris (RE) in a mandibular first molar is a common occurrence in certain ethnic groups, but the presence of RE in a mandibular second molar is a rare occurrence. In the present case, RE was identified from preoperative radiographs and confirmed using cone-beam computed tomography (CBCT). The access cavity was modified to locate the RE. Cleaning and shaping were performed with nickel-titanium rotary instruments. Obturation was completed with gutta-percha cones using AH Plus (Dentsply Detrey GmbH) as sealer. From the CBCT axial images, the RE was determined to have a Type III curvature by the De Moor classification, Type B separate RE by the Carlsen and Alexandersen classification, and radiographically, a Type i image by the Wang classification. The presence of RE in the mandibular second molar makes it essential to anticipate and treat the distolingual root canal. This case report highlights the usefulness of CBCT for assessing RE in the mandibular second molar, which can help the clinician in making a confirmatory diagnosis and assessing the morphology of the root canal. PMID:24790927

  11. Molar Functional Relations and Clinical Behavior Analysis: Implications for Assessment and Treatment

    ERIC Educational Resources Information Center

    Waltz, Thomas J.; Follette, William C.

    2009-01-01

    The experimental analysis of behavior has identified several molar functional relations that are highly relevant to clinical behavior analysis. These include matching, discounting, momentum, and variability. Matching provides a broader analysis of how multiple sources of reinforcement influence how individuals choose to allocate their time and…

  12. Evaluation of third molar development in the estimation of chronological age.

    PubMed

    Soares, Caio Belém Rodrigues Barros; Figueiroa, José Natal; Dantas, Renata Moura Xavier; Kurita, Lúcio Mitsuo; Pontual, Andréa dos Anjos; Ramos-Perez, Flávia Maria de Moraes; Perez, Danyel Elias da Cruz; Pontual, Maria Luiza dos Anjos

    2015-09-01

    The purpose of this study was to evaluate the correlation between chronological age and the degree of third molar mineralization by Demirjian's developmental stages (Demirjian et al., 1973) using panoramic radiography. From a total of 11.396 digital panoramic radiographs of patients from three oral radiology private clinics from the northeast region of Brazil, obtained from January to June 2009, 2097 radiographic images from patients aged between 6 and 22 years were selected. The images were analyzed individually by two obsevers using a 21-inch computer screen and Windows Picture and Fax Viewer. Reliability was achieved by intra- and interobserver evaluation, using the Kappa test. Chronological age, calcification stage, gender and third molar were interrelated using a multiple linear regression model, considering age as a response variable. There was reliability with Demirjian et al.'s developmental stage assesment, displaying a significant relationship between mineralization stages and patients' age (P<0.05). There was no significant difference between the average age and the calcification stage taking gender and localization of the third molar into consideration. It is possible to estimate chronological age based on Demirjian's stage of a third molar, regardless of gender and location. PMID:26164359

  13. Comparative trial between the use of amoxicillin and amoxicillin clavulanate in the removal of third molars

    PubMed Central

    Iglesias-Martín, Fernando; García-Perla-García, Alberto; Yañez-Vico, Rosa; Rosa, Elena; Arjona-Gerveno, Esther; González-Padilla, Juan D.; Gutierrez-Pérez, Jose L.

    2014-01-01

    Objectives: The purpose of this study was to compare the use of amoxicillin (1g) vs amoxicillin and clavulanate (875/125mg) after extraction of retained third molars for prevention of infectious complications. Study Design: The study involved 546 patients attending for removal a retained third molar and divided in to two groups: Group 1 - amoxicillin and clavunate (875/125mg) group (n=257) and Group 2 - amoxicillin (1g) group (n=289). All patients were recalled for investigating the possibility of infection, presence of diarrhea and further analgesic intake. Results: From a total of 546 patients, the frequency of infection was 1.4%, without no statistically differences between the two groups. Group 1 showed statistically higher presence of patients with gastrointestinal complications (p>0.05). In 546 patients, 2.7% of patients reported severe pain that would not relieve with medication. Conclusions: The results of our study show that the use of amoxicillin (1g) and amoxicillin and clavunate (875/125mg) is similar efficacious in preventing infection after retained third molar extraction but amoxicillin and clavunate (875/125mg) produces more gastrointestinal discomfort. Key words:Amoxicillin, clavulanate, third molars, complications. PMID:24880449

  14. Genetic and Environmental Molarity and Modularity of Cognitive Functioning in 2-Year-Old Twins.

    ERIC Educational Resources Information Center

    Petrill, Stephen A.; Saudino, Kimberly S.; Wilkerson, Bessie; Plomin, Robert

    2001-01-01

    Investigated genetic and environmental influences on the similarity and differences among five tests of cognitive abilities in 1,958 pairs of same-sex twins born in 1994 in the United Kingdom. Results suggest a developmental trend from modularity to molarity when considered in relation to multivariate genetic results later in life that show that…

  15. Periodontal healing two and four years after impacted lower third molar surgery. A comparative retrospective study.

    PubMed

    Kugelberg, C F

    1990-12-01

    The long-term effects on periodontal tissues of impacted lower 3rd molar surgery have been investigated in a retrospective study comprising 51 cases. The postoperative examinations took place 2 and 4 years after the surgical treatment and included both clinical and radiographic variables. Assessments were made regarding the oral hygiene status, gingival condition and periodontal tissue breakdown in terms of increased probing depths and intrabony defects. Comparing the results of the two examinations, no significant changes of the incidence of plaque and gingivitis were seen on the distal surface of the 2nd molar, nor any significant change concerning the probing depth. The proximal bone level distal to the second molar was recorded by radiographic examination with a cut-off periodontal probe as indicator. Two years postoperatively, 16.7% of the cases aged less than or equal to 25 years showed intrabony defects exceeding 4 mm, compared with 40.7% in the age group greater than or equal to 26 years. At the 4-year re-examination, the corresponding figures were 4.2% and 44.4%, respectively. The improvement concerning the alveolar bone level was mainly seen in individuals under 25 years. Some factors affecting the periodontal healing after impacted lower 3rd molar surgery are discussed. PMID:2128310

  16. Sensibility and taste alterations after impacted lower third molar extractions. A prospective cohort study

    PubMed Central

    Ridaura-Ruiz, Lourdes; Valmaseda-Castellón, Eduard; Berini-Aytés, Leonardo; Gay-Escoda, Cosme

    2012-01-01

    Objectives: To determine the incidence, severity and duration of lingual tactile and gustatory function impairments after lower third molar removal. Study Design: Prospective cohort study with intra-subject measures of 16 patients undergoing lower third molar extractions. Sensibility and gustatory functions were evaluated in each subject preoperatively, one week and one month after the extraction, using Semmes-Weinstein monofilaments and 5 different concentrations of NaCl, respectively. Additionally, all patients filled a questionnaire to assess subjective perceptions. Results: Although patients did not perceive any sensibility impairments, a statistically significant decrease was detected when Semmes-Weinstein monofilaments. This alteration was present at one week after the surgical procedure and fully recovered one month after the extraction. There were no variations regarding the gustatory function. Conclusions: Lower third molar removal under local anesthesia may cause light lingual sensibility impairment. Most of these alterations remain undetected to patients. These lingual nerve injuries are present one week after the extraction and recover one month after surgery. The taste seems to remain unaffected after these procedures. Key words:Lingual nerve, third molar, nerve injury, paresthesia, surgical extraction PMID:22322520

  17. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  18. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  19. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  20. 40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642...

  1. Characterization of Alternan, a high molar mass polysaccharide from Leuconostoc mesenteroides, by FFF-MALS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Native alternan is a high molar mass homopolymer of D-glucose produced by some strains of the bacterium Lueconostoc mesenteroides. It consists of glucose units that alternate their linkages between alpha-(1-6) and alpha-(1-3) between glucosyl units. The glucose units contained in the polysaccharid...

  2. Rotation of the upper first molar in Class I, II, and III patients

    PubMed Central

    de Oliveira Viganó, Cristiane; da Rocha, Viviane Ekerman; Junior, Laerte Ribeiro Menezes; Paranhos, Luiz Renato; Ramos, Adilson Luiz

    2016-01-01

    Objective: The aim of this study was to evaluate the mean rotation of the upper first molar (U1st M) in cast models from nontreated patients presenting: Class I, skeletal Class II, dental Class II, and skeletal Class III, comparing with Class I orthodontically treated patients. Materials and Methods: One hundred cast models were evaluated with five groups, composed of nontreated Class I (n = 20), dental Class II (n = 20), skeletal Class II (n = 20), skeletal Class III (n = 20), and treated Class I (n = 20). Measurements were taken from photocopies of the upper arches. The angle formed between a line crossing the mesiopalatal and the distal-buccalcusps of the U1st M and a line traced on mid palatal junction were measured in all samples. Results: One-way variance analysis showed that dental Class II group presented great mean rotation of the 1st molar (x = 78.95°, SD = 6.19) (P < 0.05), and in 85% of the patients from this group this angle was higher than 73°. Conclusions: The skeletal Class II and skeletal Class III groups showed similar mean position of the 1st molar, presenting rotation in approximately 50% of the patients. It can be concluded that upper molar rotation occurs mainly in dental Class II patients and shows higher mesial rotation angle. PMID:27011741

  3. A COMPARISON OF LIME AND ORANGE PECTIN BY HPSGC WITH MOLAR MASS AND VISCOSITY DETECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pectin was acid extracted from lime albedo by microwave heating under pressure. Extraction times ranged from 1 to 10 minutes. Solubilized pectin was characterized for molar mass (M), rms radius of gyration (Rg) and intrinsic viscosity (IV) by HPSEC with online light scattering and viscosity detect...

  4. Caveats when Analyzing Ultra-high Molar Mass Polymers by SEC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The analysis of ultra-high molar mass (M > 1 million g/mol) polymers via size-exclusion chromatography (SEC) presents a number of non-trivial challenges. Dissolution and full solvation may take days, as is the case for cellulose dissolution in non-complexing non degrading solvents; very low concent...

  5. Effect of restorative procedures on the strength of endodontically treated molars.

    PubMed

    Linn, J; Messer, H H

    1994-10-01

    Endodontically treated molar teeth are considered susceptible to fracture because of loss of tooth bulk. This study evaluated the significance of retaining intact marginal ridges and selective cusp coverage in preserving tooth stiffness during restoration. Strain gauges were bonded to four cusps of 36 intact extracted human lower molars. Teeth were loaded mesially and distally in a closed-loop servohydraulic system to measure stiffness. Endodontic access was followed by mesio-occlusal or mesio-occluso-distal preparation. Teeth were restored with either amalgam (no overlay), amalgam overlay, or gold overlay with partial or complete cusp coverage. Relative stiffness was calculated for all test conditions. Preserving a marginal ridge in molars did not fully conserve the strength of adjacent cusps; selective cusp coverage reinforced only the capped cusps; full occlusal coverage with gold or amalgam strengthened all cusps, but gold did so more consistently. It is more important to cover cusps than to preserve tooth structure (including a marginal ridge) in endodontically treated molar teeth. PMID:7714419

  6. Third molar development by measurements of open apices in an Italian sample of living subjects.

    PubMed

    De Luca, Stefano; Pacifici, Andrea; Pacifici, Luciano; Polimeni, Antonella; Fischetto, Sara Giulia; Velandia Palacio, Luz Andrea; Vanin, Stefano; Cameriere, Roberto

    2016-02-01

    The aim of this study is to analyse the age-predicting performance of third molar index (I3M) in dental age estimation. A multiple regression analysis was developed with chronological age as the independent variable. In order to investigate the relationship between the I3M and chronological age, the standard deviation and relative error were examined. Digitalized orthopantomographs (OPTs) of 975 Italian healthy subjects (531 female and 444 male), aged between 9 and 22 years, were studied. Third molar development was determined according to Cameriere et al. (2008). Analysis of covariance (ANCOVA) was applied to study the interaction between I3M and the gender. The difference between age and third molar index (I3M) was tested with Pearson's correlation coefficient. The I3M, the age and the gender of the subjects were used as predictive variable for age estimation. The small F-value for the gender (F = 0.042, p = 0.837) reveals that this factor does not affect the growth of the third molar. Adjusted R(2) (AdjR(2)) was used as parameter to define the best fitting function. All the regression models (linear, exponential, and polynomial) showed a similar AdjR(2). The polynomial (2nd order) fitting explains about the 78% of the total variance and do not add any relevant clinical information to the age estimation process from the third molar. The standard deviation and relative error increase with the age. The I3M has its minimum in the younger group of studied individuals and its maximum in the oldest ones, indicating that its precision and reliability decrease with the age. PMID:26706411

  7. The molar hydrodynamic volume changes of factor VIIa due to GlycoPEGylation.

    PubMed

    Plesner, Bitten; Westh, Peter; Hvidt, Søren; Nielsen, Anders D

    2011-06-01

    The effects of GlycoPEGylation on the molar hydrodynamic volume of recombinant human rFVIIa were investigated using rFVIIa and two GlycoPEGylated recombinant human FVIIa derivatives, a linear 10kDa PEG and a branched 40kDa PEG, respectively. Molar hydrodynamic volumes were determined by capillary viscometry and mass spectrometry. The intrinsic viscosities of rFVIIa, its two GlycoPEGylated compounds, and of linear 8kDa, 10kDa, 20kDa and branched 40kDa PEG polymers were determined. The measured intrinsic viscosity of rFVIIa is 6.0mL/g, while the intrinsic viscosities of 10kDa PEG-rFVIIa and 40kDa PEG-rFVIIa are 29.5mL/g and 79.0mL/g, respectively. The intrinsic viscosities of the linear PEG polymers are 20, 22.6 and 41.4mL/g for 8, 10, and 20kDa, respectively, and 61.1mL/g for the branched 40kDa PEG. From the results of the intrinsic viscosity and MALDI-TOF measurements it is evident, that the molar hydrodynamic volume of the conjugated protein is not just an addition of the molar hydrodynamic volume of the PEG and the protein. The molar hydrodynamic volume of the GlycoPEGylated protein is larger than the volume of its composites. These results suggest that both the linear and the branched PEG are not wrapped around the surface of rFVIIa but are chains that are significantly stretched out when attached to the protein. PMID:21429688

  8. No evidence for apoptosis of decidual leucocytes in normal and molar pregnancy: implications for immune privilege

    PubMed Central

    PONGCHAROEN, S; BULMER, J N; SEARLE, R F

    2004-01-01

    Complete hydatidiform moles are totally paternally derived and represent complete allografts that might be expected to provoke maternal immune rejection. Our previous and other studies have shown expression of Fas by increased numbers of activated decidual CD4+ T cells in both complete and partial molar pregnancy as well as increased FasL+ expression by molar trophoblasts compared with trophoblasts in normal pregnancies. As the Fas/FasL system represents a major apoptotic pathway that can play a role in immune privilege, the aim of this study was to investigate whether apoptosis of decidual immune cells, particularly T cells, could be responsible for maternal immune tolerance in molar pregnancy. Using terminal deoxynucleotidyl transferase (TdT)-mediated nick end-labelling (TUNEL), a significant increase in TUNEL+ cells was demonstrated in decidua associated with partial (P = 0·0052) and complete (P = 0·0096) hydatidiform mole compared with normal early pregnancy. Co-labelling immunoperoxidase studies showed that the TUNEL+ cells in both normal and molar pregnancies were not activated CD45RO+ immune cells, CD3+ T cells, CD56+ uterine natural killer (NK) cells or CD14+ CD68+ macrophages. Double immunohistochemical labelling with antiactive caspase-3 and leucocyte markers confirmed the lack of leucocyte apoptosis. Double immunostaining with anticytokeratin to detect trophoblast and M30 CytoDeath, which detects a neoepitope of cytokeratin 18 revealed after caspase-mediated cleavage, revealed apoptotic extravillous trophoblast cells within decidual tissue. We conclude that there is no evidence that apoptosis of decidual leucocytes plays a role in maintaining maternal tolerance in either normal or molar pregnancy. PMID:15498045

  9. Negotiability of Second Mesiobuccal Canals in Maxillary Molars Using a Reciprocating System.

    PubMed

    Zuolo, Mario Luis; Carvalho, Maria Cristina; De-Deus, Gustavo

    2015-11-01

    The aim of this prospective case series report was to assess the frequency in which the Reciproc R25 instrument (VDW, Munich, Germany) is able to scout and reach the full working length (WL) in second mesiobuccal (MB2) canals from maxillary molars. Conventional hand file negotiation was used as the reference technique for comparison. Maxillary molars (270 first molars and 71 second molars) were included in this study. After local anesthesia, the tooth was isolated with a rubber dam, and traditional straight-line access was made. After locating both first mesiobuccal and MB2 canals, patients were randomly assigned to one of the experimental groups (conventional hand filing preparation or R25 Reciproc preparation). All cases in which the hand files (G1) and R25 instrument (G2) were able to reach the fully electronically determined WL were classified as "reaching full WL" (RFWL). All cases in which the hand files (G1) and R25 instrument (G2) were unable to negotiate the full-length canal were classified as "not reaching full WL" (NRFWL). The number of root canals classified as RFWL and NRFWL from both groups were recorded and tabulated on an Excel data sheet (Microsoft, Redmond, WA). The frequency distributions (%) of root canals classified as RFWL and NRFWL were compared with overall-treated canals and for each treatment approach (hand file and R25 instrument) using a Pearson chi-square test. In group 1, the hand file approach reached the full WL in 57.48% of cases, whereas in group 2 the R25 instrument reached the full WL in 85.63% of cases. Three file separations occurred in each group while negotiating the MB2 canal. According to this study, the R25 instrument was 32% more effective when compared with hand files in scouting and negotiating MB2 canals in maxillary first and second molars. There was no difference with regard to file separation when comparing both preparation techniques. PMID:26443438

  10. A Cone-Beam Computed Tomographic Study on Mandibular First Molars in a Chinese Subpopulation

    PubMed Central

    Ma, Yue; Han, Ting; Chen, Xinyu; Wan, Fang; Lu, Yating; Yan, Songhe; Wang, Yan

    2015-01-01

    The purpose of this study was to conduct a cone-beam computed tomographic (CBCT) investigation on the root and canal configuration of the mandibular first molars, especially the morphology of the disto-lingual (DL) root, in a Chinese subpopulation. A total of 910 CBCT images of the mandibular first molars were collected from 455 patients who underwent CBCT examinations as a preoperative assessment for implants or orthodontic treatment. The following information was analyzed and evaluated: tooth position, gender, root and root canal number per tooth, root canal type of the mesial root(s) and distal root(s), angle of the DL root canal curvature, distance between two distal canal orifices in the teeth with DL root, and angle of disto-buccal canal orifice–disto-lingual canal orifice–mesio-lingual canal orifice (DB-DL-ML). Most of the mandibular first molars (64.9%, n = 591) had two roots with three root canals, and most of the mesial root canals (87.7%, n = 798) were type VI. The prevalence of the DL root was 22.1% (n = 201). The right side had a higher prevalence of DL root than the left side (p<0.05). Additionally, the curvature of the DL root canal were greater in the bucco-lingual (BL) orientation (30.10°±14.02°) than in the mesio-distal (MD) orientation (14.03°± 8.56°) (p<0.05). Overall there was a high prevalence of DL root in the mandibular first molars, and most of the DL roots were curved in different degrees. This study provided detailed information about the root canal morphology of the mandibular first molars in a Chinese subpopulation. PMID:26241480

  11. Evolution and function of the upper molar talon and its dietary implications in microbats.

    PubMed

    Gutzwiller, Sarah C; Hunter, John P

    2015-11-01

    The evolution of mammalian molars has been marked by transitions representing significant changes in shape and function. One such transition is the addition and elaboration of the talon, the distolingual region of the ancestral tribosphenic upper molar of therian mammals and some extinct relatives. This study uses suborder Microchiroptera as a case study to explore the adaptive implications of the expansion of the talon on the tribosphenic molar, specifically focusing on the talon's role in the compression and shear of food during breakdown. Three-dimensional computer renderings of casts of the upper left first molars were created for microbat species of a variety of dietary categories (frugivore, etc.) and physical properties of food (hard and soft). Relief Index (RFI) was measured to estimate the topography and function of the whole tooth and of the talon and trigon (the remaining primitive tribosphenic region) individually, in order to examine 1) how the shape of the whole tooth, trigon, and talon reflects the compromise between their crushing and shearing functions, 2) how whole tooth, trigon, and talon function differs according to diet, and 3) how the presence of the talon affects overall molar function. Results suggest that RFI of both the whole tooth and the trigon varies according to dietary groups, with frugivores having greater crushing function when compared with the other groups. The talon, however, consistently has low RFI (a flatter topography), and its presence lowers the RFI of the whole tooth across all dietary categories, suggesting that the talon is primarily functioning in crushing during food breakdown. The potential benefits of a crushing talon for microbats of various dietary groups are discussed. PMID:26473768

  12. Sex assessment efficacy of permanent maxillary first molar cusp dimensions in Indians

    PubMed Central

    Yadav, Achla Bharti; Angadi, Punnya V.; Yadav, Sumit Kumar

    2015-01-01

    Background: The human first maxillary molar provides clues about evolution and is functionally important. It has four main cusps, and each cusp has an independent growth pattern and different evolutionary background. Though less explored, the analysis based on measurement of each cusp appears to be more meaningful biologically than conventional measurements of the whole crown. Aim: This study aimed to demonstrate the extent of sexual dimorphism in permanent maxillary first molar cusp diameters and their potential utility in sex prediction among Indians using logistic regression analysis (LRA). Materials and Methods: The mesiodistal and buccolingual (BL) crown diameters along with cusp dimensions and cusp indices of right maxillary first molar were measured in an Indian sample (149 males, 151 females; age range of 18–30 years). The possible sex dimorphism in these parameters was evaluated, and LRA was performed to ascertain their usefulness in sex prediction. Results: BL crown dimension and the hypocone (distolingual) cusp showed the highest sexual dimorphism. The combination of metacone and hypocone, i.e., distal cusp diameters among cusp parameters showed the highest accuracy (61.3%). While, on combining all the crown and cusp diameters together the overall accuracy was raised (64.3%). Conclusion: This study supports the ontogeny hypothesis suggesting that early-forming mesial cusps demonstrate less sexual variation as compared to subsequently formed distal cusps in the maxillary molar. Though the sex identification accuracy for cusp diameters of the permanent maxillary first molar in Indians is relatively moderate (≈61%), it can be used as an adjunct for sexing of adult Indians in forensic contexts. PMID:26681853

  13. Impacted Mandibular Third Molars: Review of Literature and a Proposal of a Combined Clinical and Radiological Classification

    PubMed Central

    Santosh, P

    2015-01-01

    Tooth impaction is a pathological situation where a tooth fails to attain its normal functional position. Impacted third molars are commonly encountered in routine dental practice. The impaction rate is higher for third molars when compared with other teeth. The mandibular third molar impaction is said to be due to the inadequate space between the distal of the second mandibular molar and the anterior border of the ascending ramus of the mandible. Impacted teeth may remain asymptomatic or may be associated with various pathologies such as caries, pericoronitis, cysts, tumors, and also root resorption of the adjacent tooth. Even though various classifications exist in the literature, none of those address the combined clinical and radiologic assessment of the impacted third molar. Literature search using the advanced features of various databases such as PubMed, Scopus, Embase, Google Scholar, Directory of Open Access Journals and Cochrane electronic databases was carried out. Keywords like impaction, mandibular third molar, impacted mandibular third molar, complications, anatomy, inferior alveolar nerve injury, lingual nerve injury were used to search the databases. A total of 826 articles were screened, and 50 articles were included in the review which was obtained from 1980 to February 2015. In the present paper, the authors have proposed a classification based on clinical and radiological assessment of the impacted mandibular third molar. PMID:26229709

  14. Impacted Mandibular Third Molars: Review of Literature and a Proposal of a Combined Clinical and Radiological Classification.

    PubMed

    Santosh, P

    2015-01-01

    Tooth impaction is a pathological situation where a tooth fails to attain its normal functional position. Impacted third molars are commonly encountered in routine dental practice. The impaction rate is higher for third molars when compared with other teeth. The mandibular third molar impaction is said to be due to the inadequate space between the distal of the second mandibular molar and the anterior border of the ascending ramus of the mandible. Impacted teeth may remain asymptomatic or may be associated with various pathologies such as caries, pericoronitis, cysts, tumors, and also root resorption of the adjacent tooth. Even though various classifications exist in the literature, none of those address the combined clinical and radiologic assessment of the impacted third molar. Literature search using the advanced features of various databases such as PubMed, Scopus, Embase, Google Scholar, Directory of Open Access Journals and Cochrane electronic databases was carried out. Keywords like impaction, mandibular third molar, impacted mandibular third molar, complications, anatomy, inferior alveolar nerve injury, lingual nerve injury were used to search the databases. A total of 826 articles were screened, and 50 articles were included in the review which was obtained from 1980 to February 2015. In the present paper, the authors have proposed a classification based on clinical and radiological assessment of the impacted mandibular third molar. PMID:26229709

  15. Analysis of midpalatal miniscrew-assisted maxillary molar distalization patterns with simultaneous use of fixed appliances: A preliminary study

    PubMed Central

    Mah, Su-Jung; Kim, Ji-Eun; Ahn, Eun Jin; Nam, Jong-Hyun; Kim, Ji-Young

    2016-01-01

    Skeletal anchorage-assisted upper molar distalization has become one of the standard treatment modalities for the correction of Class II malocclusion. The purpose of this study was to analyze maxillary molar movement patterns according to appliance design, with the simultaneous use of buccal fixed orthodontic appliances. The authors devised two distinct types of midpalatal miniscrew-assisted maxillary molar distalizers, a lingual arch type and a pendulum type. Fourteen patients treated with one of the two types of distalizers were enrolled in the study, and the patterns of tooth movement associated with each type were compared. Pre- and post-treatment lateral cephalograms were analyzed. The lingual arch type was associated with relatively bodily upper molar distalization, while the pendulum type was associated with distal tipping with intrusion of the upper molar. Clinicians should be aware of the expected tooth movement associated with each appliance design. Further well designed studies with larger sample sizes are required. PMID:26877983

  16. Prevalence of molar incisor hypomineralization in 7–9-year-old children of Bengaluru City, India

    PubMed Central

    Subramaniam, Priya; Gupta, Tulika; Sharma, Akhilesh

    2016-01-01

    Background: Molar incisor hypomineralization (MIH) is a developmental defect. The prevalence of MIH ranges widely from 2.4% to 40.2%. Aim: This study was under taken to determine the prevalence of MIH in 7–9-year-old children of Bengaluru City, India. Materials and Methods: A cross-sectional epidemiological study was conducted in a representative sample of 2500 school children aged 7–9 years of Bengaluru, India. Oral examination was carried out by a single trained calibrated examiner under natural daylight. Results: Twelve children (0.48%) were diagnosed with MIH. A total of 68 teeth were observed with MIH. All four first permanent molars were affected in 50% of children. In the molar group, mandibular molars (29.41%) were more frequently affected than maxillary molars (27.94%). Conclusion: The prevalence of MIH in 7–9-year-old children of Bengaluru was 0.48%, with no gender predilection. PMID:27041893

  17. Analysis of midpalatal miniscrew-assisted maxillary molar distalization patterns with simultaneous use of fixed appliances: A preliminary study.

    PubMed

    Mah, Su-Jung; Kim, Ji-Eun; Ahn, Eun Jin; Nam, Jong-Hyun; Kim, Ji-Young; Kang, Yoon-Goo

    2016-01-01

    Skeletal anchorage-assisted upper molar distalization has become one of the standard treatment modalities for the correction of Class II malocclusion. The purpose of this study was to analyze maxillary molar movement patterns according to appliance design, with the simultaneous use of buccal fixed orthodontic appliances. The authors devised two distinct types of midpalatal miniscrew-assisted maxillary molar distalizers, a lingual arch type and a pendulum type. Fourteen patients treated with one of the two types of distalizers were enrolled in the study, and the patterns of tooth movement associated with each type were compared. Pre- and post-treatment lateral cephalograms were analyzed. The lingual arch type was associated with relatively bodily upper molar distalization, while the pendulum type was associated with distal tipping with intrusion of the upper molar. Clinicians should be aware of the expected tooth movement associated with each appliance design. Further well designed studies with larger sample sizes are required. PMID:26877983

  18. Rescue therapy with orthodontic traction to manage severely impacted mandibular second molars and to restore an alveolar bone defect.

    PubMed

    Choi, Yoon Jeong; Huh, Jong-Ki; Chung, Chooryung J; Kim, Kyung-Ho

    2016-08-01

    This case report describes the successful treatment of severely impacted mandibular second molars with severe apical root resorption of the mandibular first molars. The vertically impacted second molars were orthodontically moved (using orthodontic mini-implants) without additional root resorption of the first molars. The orthodontic treatment provided a satisfactory and stable outcome by improving the periodontium surrounding the first and second molars. The treatment also eliminated the need for prosthetic treatment by preserving the first and second molars. PMID:27476369

  19. Proximity of the mandibular molar root apex from the buccal bone surface: a cone-beam computed tomographic study

    PubMed Central

    Kim, Dokyung; Jin, Myoung-Uk

    2016-01-01

    Objectives The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. Materials and Methods Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. Results The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). Conclusions For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration. PMID:27508159

  20. Impact of Aprotinin - A Proteolytic Enzyme on Postsurgical Symptoms in Patients Undergoing Third Molar Surgeries

    PubMed Central

    Jegadeesan, Visakan

    2016-01-01

    Introduction Dealing with postoperative pain and inflammation remains an arena for never ending research. Different agents have been the subject of many studies to prevent the occurrence of unpleasant postoperative sequel. Extraction of third molars is often associated with significant deterioration in oral health related quality of life (physical, social and psychological) in immediate postoperative period. The complaints of pain, swelling and limitation of mouth opening, which ensue as a result of acute inflammatory response, are frequent consequences of postsurgical procedures involving extraction of impacted 3rd molars. Aim Aprotinin, a naturally occurring protease inhibitor was assessed for its effectiveness in plummeting postsurgical pain and swelling, after surgical removal of impacted 3rd molars. Materials and Methods Thirty randomly selected adult patients age ranging from 16-35 years, who required simultaneous surgical removal of bilateral impacted mandibular third molars were recruited. Before the surgical procedure, randomly selected side of the patient was injected with 1 m of 10,000 Kallikrein Inactivator Units (KIU) of aprotinin sub-mucosally around the surgical site and the contra lateral side with 1ml of isotonic saline as a control following which adequate local anaesthesia was obtained. The surgical removal of impacted 3rd molars was conducted in a similar manner on both test and control sides on all patients. Postoperatively, the patients were evaluated for pain and swelling for one week i.e., 1st, 2nd and 7th day. Results It was observed that there was marked clinical reduction in postoperative pain and swelling. There were no adverse affects observed after using aprotinin. Conclusion Since, the current pharmacologic agents being used have adverse effects and associated morbidity which still pose a problem, aprotinin a naturally occurring agent could be efficiently used after surgical extraction of 3rd molars in management of postsurgical

  1. Acute cervical artery dissection after a dental procedure due to a second inferior molar infection.

    PubMed

    Delgado, Montserrat G; Riesco, Nuria; Murias, Eduardo; Calleja, Sergio

    2015-01-01

    Periodontal infections might represent one of the causative factors for cervical artery dissection. We present a case of a 49-year-old woman admitted due to headache. The patient had been suffering from a right second inferior molar infection with a cervical phlegmon for 1 week prior to admission. On 2 October 2014, the patient went to the dentist and a molar extraction was performed in the morning. In the afternoon, the patient began to experience right hemifacial pain that progressed towards an intense and bilateral headache. Neurological status at the time of admission revealed right miosis, ptosis and conjuntival hyperaemia. A CT angiography showed a right internal carotid artery dissection provoking a high-degree stenosis. The relationship between periodontal infection and vascular disease has been previously presented. Microbial agents may directly, and inflammatory and immunological host response indirectly, influence inflammatory changes in cervical arteries favouring dissections with minor traumas. PMID:26038385

  2. Deciduous teeth of the Neandertal mandible from Molare Shelter, near Scario (Salerno, Italy).

    PubMed

    Mallegni, F; Ronchitelli, A T

    1989-08-01

    Excavations at hearth levels at the Molare Shelter in 1985 yielded the mandible of a 3-4-year-old child. The associated lithic artifacts recovered with it are Mousterian. Its features, although quite archaic, are within the known range of variation of Neandertals. Four deciduous molars are still preserved in the mandible. They were compared with other known specimens, which date to the Middle and Upper Pleistocene. The metrical characteristics are surprisingly primitive, within the range of variation of Homo erectus, or at least within that of European Pre-Neandertals, more so than within the variability of typical Neandertal specimens. On the other hand, the morphological characteristics, except for a few that are decidedly plesiomorph, are predominantly Neandertal. PMID:2672830

  3. Delayed removal of a maxillary third molar from the infratemporal fossa.

    PubMed

    Gómez-Oliveira, Guillermo; Arribas-García, Ignacio; Alvarez-Flores, Modesto; Gregoire-Ferriol, Johanna; Martínez-Gimeno, Carlos

    2010-05-01

    Removal of an impacted superior third molar is usually a simple and uncomplicated procedure for an Oral and Maxillofacial Surgeon. Nevertheless, complications are possible and include infection, facial swallowing, trismus, wound dehiscence, root fracture or even orosinusal fistula. Iatrogenic displacement into the infratemporal fossa is frequently mentioned but rarely reported. This anatomical fossa includes several important structures such as the internal maxillary artery, the venous pterygoid plexus, the sphenopalatine nerve, the coronoid process of the mandible and the pterygoid muscles. Recommended treatment includes immediate surgical removal if possible or initial observation and secondary removal, as necessary, because of infection, limited mandibular movement, inability to extract the tooth, or the patient's psychological unease. Sometimes, the displaced tooth may spontaneously migrate inferiorly and becomes accessible intraorally. This report describes the location and secondary surgical removal of a left maxillary third molar displaced into the infratemporal fossa, two weeks after first attempt at extraction. PMID:20038889

  4. First molar size and wear within and among modern hunter-gatherers and agricultural populations.

    PubMed

    Górka, Katarzyna; Romero, Alejandro; Pérez-Pérez, Alejandro

    2015-08-01

    Apart from reflecting modern human dental variation, differences in dental size among populations provide a means for studying continuous evolutionary processes and their mechanisms. Dental wear, on the other hand, has been widely used to infer dietary adaptations and variability among or within diverse ancient human populations. Few such studies have focused on modern foragers and farmers, however, and diverse methods have been used. This research aimed to apply a single, standardized, and systematic quantitative procedure to measure dental size and dentin exposure in order to analyze differences among several hunter-gatherer and agricultural populations from various environments and geographic origins. In particular, we focused on sexual dimorphism and intergroup differences in the upper and lower first molars. Results indicated no sexual dimorphism in molar size and wear within the studied populations. Despite the great ethnographic variation in subsistence strategies among these populations, our findings suggest that differences in sexual division of labor do not affect dietary wear patterns. PMID:26032341

  5. Morphologic analysis of third-molar maturity by digital orthopantomographic assessment.

    PubMed

    Introna, Francesco; Santoro, Valeria; De Donno, Antonio; Belviso, Maura

    2008-03-01

    Accurate timing of the eruption of first and permanent teeth is an important parameter in forensic odontology to establish the age of dead or live individuals. Determination of adulthood may determine, for example, whether an individual convicted of a crime is sentenced as an adult and incarcerated in a state penal institution or as a juvenile and sent to a juvenile camp. At present, there is a large immigrant population in Italy, and young foreign criminals sometimes have false passports bearing a later birth date, with the aim of evading punishment. In such circumstances, age determination is becoming a significant forensic issue.Late in adolescence, after formation of the premolars and canines, only the third molars continue to develop. According to several studies, although the third molars are the most variable teeth in the dentition, they remain the most reliable biologic indicator available for estimation of age during the middle teens and early twenties.In this study, the authors test the possibilities offered by orthopantomography executed by means of digital technology, with the aim of exploiting the advantages of the computerized digital technique compared with the conventional technique, to determine adult age on the basis of root development of the third molar.Digital radiography is simple to use, quick, and effective, allowing superimposition and enlargement; the images can be electronically stored and transported. In comparison with traditional orthopantomography, the digital technique features greater diagnostic accuracy of some anatomic structures: upper and lower front teeth, root apexes, floor of the nasal fossa and maxillary sinus, nasal septum, mandibular condylus. Moreover, digital orthopantomography suffers less from artifacts.The digital orthopantomographies of 83 Caucasian subjects (43 females and 40 males) aged between 16 and 22 years were analyzed in standard conditions, assessing the degree of maturation of the upper and lower third

  6. Rare Root Canal Configuration of Bilateral Maxillary Second Molar Using Cone-beam Computed Tomographic Scanning.

    PubMed

    Zeng, Chang; Shen, Ya; Guan, Xiaoyue; Wang, Xin; Fan, Mingwen; Li, Yuhong

    2016-04-01

    The aim of this article was to present a right maxillary second molar with an unusual root canal morphology of 4 roots and 5 canals as confirmed by cone-beam computed tomographic (CBCT) imaging. The tooth had a C-shaped mesiobuccal root (CBCT imaging revealed that the root was closer to the palate than the buccal side) with 2 canals, 2 fused distobuccal roots with 2 separate canals, and 1 normal bulky palatal root with 1 canal. After thoroughly examining the rare anatomy, root canal treatment was applied on the tooth. This article shows the complexity of maxillary second molar variation and shows the significance of CBCT imaging in the confirmation of the 3-dimensional anatomy of teeth and endodontic treatment. PMID:26920931

  7. Coronectomy of mandibular third molars: A clinical protocol to avoid inferior alveolar nerve injury.

    PubMed

    Monaco, Giuseppe; Vignudelli, Elisabetta; Diazzi, Michele; Marchetti, Claudio; Corinaldesi, Giuseppe

    2015-10-01

    Coronectomy is a surgical procedure for the treatment of mandibular third molars in close proximity to the mandibular canal. Unfortunately, often the surgical protocol is not described step by step and it is difficult for the clinician to assess the key factors that are important for the success of this procedure. The aim of this paper is to propose and describe a standardized surgical protocol to improve the success of the technique. The treatment approach, for the most common types of third molars impaction is analysed. Each step of the surgical procedure is described in details and a new type of crown section is proposed. The presented protocol is proposed in order to define a clinical practitioner's guide that could help the surgeon who approaches coronectomy for the first times. PMID:26321069

  8. Molar mass and temperature dependence of the thermodiffusion of polyethylene oxide in water/ethanol mixtures

    NASA Astrophysics Data System (ADS)

    Wang, Zilin; Afanasenkau, Dzmitry; Dong, Minjie; Huang, Danni; Wiegand, Simone

    2014-08-01

    In this work, we study the molar mass dependence of the thermodiffusion of polyethylene oxide at different temperatures in ethanol, water/ethanol mixture (cwater = 0.7), and water in a molar mass range up to Mw = 180 000 g/mol. Due to the low solubility of polyethylene oxide oligomers in ethanol the measurements are limited up to Mw = 2200 g/mol. The specific water/ethanol concentration 0.7 has been chosen, because at this weight fraction the thermal diffusion coefficient, DT, of water/ethanol vanishes so that the system can be treated as a pseudo binary mixture. The addition of ethanol will degrade the solvent quality, so that we expect a change of the interaction energies between polymer and solvent. The analysis of the experimental data within a theoretical model shows the need of a refined model, which takes specific interactions into account.

  9. INDIRECT PULP TREATMENT IN A PERMANENT MOLAR: CASE REPORT OF 4-YEAR FOLLOW-UP

    PubMed Central

    Fagundes, Ticiane Cestari; Barata, Terezinha Jesus Esteves; Prakki, Anuradha; Bresciani, Eduardo; Pereira, José Carlos

    2009-01-01

    This case report describes the Indirect Pulp Treatment (IPT) of deep caries lesion in a permanent molar. A 16-year-old male patient reported discomfort associated with thermal stimulation on the permanent mandibular left first molar. The radiographs revealed a deep distal caries lesion, very close to the pulp, absence of radiolucencies in the periapical region, and absence of periodontal space thickening. Pulp sensitivity was confirmed by thermal pulp vitality tests. Based on the main complaint and the clinical and radiographic examinations, the treatment plan was established to preserve pulp vitality. Clinical procedures consisted of removing the infected dentin and lining the caries-affected dentin with calcium hydroxide paste. The tooth was provisionally sealed for approximately 60 days. After this period, tooth vitality was confirmed, the remaining carious dentin was removed, and the tooth was restored. At 4-year follow-up, no clinical or radiographic pathological findings were found. PMID:19148410

  10. Severe Impaction of the Primary Mandibular Second Molar Accompanied by Displacement of the Permanent Second Premolar

    PubMed Central

    Matsuyama, Junko; Kinoshita-Kawano, Shoko; Hayashi-Sakai, Sachiko; Mitomi, Tomoe; Sano-Asahito, Tomiko

    2015-01-01

    Tooth impaction is defined as any tooth that fails to erupt into a normal functional position and remains unerupted beyond the time at which it should normally erupt. Reports of impaction and eruption failure in primary teeth are relatively rare compared to permanent teeth. We report 2 rare cases where the second premolar was located on the occlusal side of the impacted mandibular second primary molar. In the first case, the succedaneous permanent tooth erupted after extraction of the primary tooth, fenestration, and traction. In the second case, the succedaneous permanent tooth erupted without fenestration or traction. Although the etiology of the tooth displacement was unknown in both cases, inhibition of the eruptive movement of the primary molar may have been associated with displacement of the succedaneous permanent premolar. PMID:25810929

  11. [Using Metronidazole and Hydroxyapatite for preventing dry socket after extraction of impacted mandibular 3rd molar

    PubMed

    Xue, Z X; Mao, T Q

    1993-03-01

    Dry socket is one of the most frequent complications after teeth extraction,especially in impacted mandibular third molars.The etilogy and prevention is not clear.This study id based on principles of clinical epidemiology.Randomized double-blind method was carried out in 549 patients to test the value of the prophylactic use of Hydroxyapatite,to test the value of the prophylactic use of Hydroxyapatite and Metronidazole,placed in the sockets of extracted impacted mandibular third molars.The results of the incidence of DS was 7.1% of Metronidazole treated sockets,and 2.1% of Hydroxyapatite treated sockets,It is concluded that Hydroxyapatite is an effective preventive factor for dry socket,The possible mechanism of Hydroxyapatite and the dry socket etiology were discussed. PMID:15159869

  12. Cuspal deflection in molars in relation to endodontic and restorative procedures.

    PubMed

    Panitvisai, P; Messer, H H

    1995-02-01

    The extent of cuspal flexure following endodontic and restorative procedures has important consequences for potential fracture. This study was undertaken to determine the extent to which cusps of molars are weakened by progressively larger restorative preparations and endodontic access. Cuspal flexure of 13 extracted, intact human mandibular molars was measured under controlled occlusal loading. A ramped load of 100 N was applied to the mesial cusps via a steel sphere, using a closed-loop servohydraulic testing machine. Lateral cuspal displacement was recorded by linear measuring devices (direct current differential transformers) accurate to 1 micron. Increasingly extensive MO or MOD cavity preparations followed by endodontic access were cut in each tooth. Cuspal deflection increased with increasing cavity size and was greatest following endodontic access. Cuspal deflections of more than 10 microns were observed. These findings reinforce the importance of cuspal coverage to minimize the danger of marginal leakage and cuspal fracture in endodontically treated teeth. PMID:7714437

  13. Suspected ovarian molar pregnancy after assisted reproductive technology conception: a diagnostic challenge.

    PubMed

    Obeidi, Nedaa; Tchrakian, Nairi; Abu Saadeh, Feras; Mocanu, Edgar

    2015-01-01

    A 32-year-old patient with primary infertility received in vitro fertilisation (IVF) therapy. Four weeks later she developed intermittent left iliac fossa pain. Transvaginal ultrasound showed an empty uterus and an adnexal mass adjacent to the right ovary. Serum β-human chronic gonadotropin was 33,492 IU/L. At laparoscopy a mass attached to right ovary, suggestive of a right ovarian ectopic pregnancy, was excised. Histological examination confirmed an ovarian ectopic gestation, but noted enlarged chorionic villi and trophoblastic atypia, which raised the suspicion of molar pregnancy. Subsequent p57 immunohistochemistry and DNA ploidy studies excluded a mole, however. Cases of suspected molar disease in ectopic pregnancy present a diagnostic challenge for both clinicians and histopathologists, and establishing a definitive diagnosis may be difficult. PMID:25837656

  14. A geometric morphometric analysis of hominin upper second and third molars, with particular emphasis on European Pleistocene populations.

    PubMed

    Gómez-Robles, Aida; Bermúdez de Castro, José María; Martinón-Torres, María; Prado-Simón, Leyre; Arsuaga, Juan Luis

    2012-09-01

    The study of dental morphology by means of geometric morphometric methods allows for a detailed and quantitative comparison of hominin species that is useful for taxonomic assignment and phylogenetic reconstruction. Upper second and third molars have been studied in a comprehensive sample of Plio- and Pleistocene hominins from African, Asian and European sites in order to complete our analysis of the upper postcanine dentition. Intraspecific variation in these two molars is high, but some interspecific trends can be identified. Both molars exhibit a strong reduction of the distal cusps in recent hominin species, namely European Homo heidelbergensis, Homo neanderthalensis and Homo sapiens, but this reduction shows specific patterns and proportions in the three groups. Second molars tend to show four well developed cusps in earlier hominin species and their morphology is only marginally affected by allometric effects. Third molars can be incipiently reduced in earlier species and they evince a significant allometric component, identified both inter- and intraspecifically. European Middle Pleistocene fossils from Sima de los Huesos (SH) show a very strong reduction of these two molars, even more marked than the reduction observed in Neanderthals and in modern human populations. The highly derived shape of SH molars points to an early acquisition of typical Neanderthal dental traits by pre-Neanderthal populations and to a deviation of this population from mean morphologies of other European Middle Pleistocene groups. PMID:22840714

  15. Probing the homogeneity of the isotopic composition and molar mass of the ‘Avogadro’-crystal

    NASA Astrophysics Data System (ADS)

    Pramann, Axel; Lee, Kyoung-Seok; Noordmann, Janine; Rienitz, Olaf

    2015-12-01

    Improved measurements on silicon crystal samples highly enriched in the 28Si isotope (known as ‘Si28’ or AVO28 crystal material) have been carried out at PTB to investigate local isotopic variations in the original crystal. This material was used for the determination of the Avogadro constant NA and therefore plays an important role in the upcoming redefinition of the SI units kilogram and mole, using fundamental constants. Subsamples of the original crystal have been extensively studied over the past few years at the National Research Council (NRC, Canada), the National Metrology Institute of Japan (NMIJ, Japan), the National Institute of Standards and Technology (NIST, USA), the National Institute of Metrology (NIM, People’s Republic of China), and multiple times at PTB. In this study, four to five discrete, but adjacent samples were taken from three distinct axial positions of the crystal to obtain a more systematic and comprehensive understanding of the distribution of the isotopic composition and molar mass throughout the crystal. Moreover, improved state-of-the-art techniques in the experimental measurements as well as the evaluation approach and the determination of the calibration factors were utilized. The average molar mass of the measured samples is M  =  27.976 970 12(12) g mol-1 with a relative combined uncertainty uc,rel(M)  =  4.4 ×10-9. This value is in astounding agreement with the values of single samples measured and published by NIST, NMIJ, and PTB. With respect to the associated uncertainties, no significant variations in the molar mass and the isotopic composition as a function of the sample position in the boule were observed and thus could not be traced back to an inherent property of the crystal. This means that the crystal is not only ‘homogeneous’ with respect to molar mass but also has predominantly homogeneous distribution of the three stable Si isotopes.

  16. Spontaneous complete resolution of a radiolucent shadow associated with an impacted mandibular third molar.

    PubMed

    Naqvi, Ambareen; Steel, Clare; Koshal, Sonita

    2016-02-01

    Impacted third molars are commonly associated with areas of radiolucency, and treatment can damage the adjacent structures, specifically the inferior alveolar nerve. We report a rare and interesting case of a large radiolucent area associated with an impacted mandibular wisdom tooth that resolved over 7 years with no intervention. We postulate that the unexpected movement of the tooth over this time caused spontaneous resolution of the cystic space, a natural decompression, which highlights the option of monitoring. PMID:26657717

  17. Effects of localmelatonin application on post-extraction sockets after third molar surgery. A pilot study

    PubMed Central

    Fernández-Tresguerres, Isabel; Ortega-Aranegui, Ricardo; López-Quiles, Juan

    2014-01-01

    Objectives: The purpose of this study was to assess the anti-inflammatory, analgesic and osteogenic early effects of melatonin on post-extraction sockets ofpatients requiring third molars extraction. Study Design: A randomized, triple-blind clinical trial was made using a split-mouth design. Both lower third molars of 10 patients were extracted and 3 mg of local melatonin or placebo were applied. Concentrations of interleukin-6 and nitrotyrosine were determined on samples of the clot from the socket by independent ELISA tests. Radiographic bone density was evaluated by measuring Hounsfield Units in panoramic and cross sections obtained by digital scanner. Statistycal analysis by Kolmogorov-Smirnov test was performed for ELISA data. Bone density was analyzed by Shapiro-Wilk test. Subsequently t test was applied. P<0.05 was considered to be significant. Results: The concentration of interleukin-6 increased with the application of melatonin without statistically significance (361.32 ± 235.22 pg/ml vs 262.58 ± 233.92 pg/ml). Nitrotyrosine concentrations showed values below to the detectability pattern (<0.001 nM) in Optic Density curve. Bone density in panoramic sections at socket after melatonin application showed no significant difference (561.98 ± 105.92 HU vs 598.82 ± 209.03 HU). In cross sections, bone density in the alveolar region showed no significant difference(377.42 ± 125.67 HU vs 347.56 ± 97.02 HU). Conclusions: Within the limitations of this pilot study, no differences with the application of melatonin were found in terms of the concentration of interleukin-6 and bone density in post-extraction socket of retained mandibular third molars. Key words:Melatonin, inflammation, pain, bone density, third molar surgery. PMID:25350595

  18. Indications and Risk Factors for Complications of Lower Third Molar Surgery in a Nigerian Teaching Hospital

    PubMed Central

    Osunde, OD; Saheeb, BD; Bassey, GO

    2014-01-01

    Background: The surgical extraction of impacted third molars is a common oral surgical procedure, and it is often associated with complications such as sensory nerve damage, dry socket, pain, swelling, trismus, infection and hemorrhage. Aim: The aim of this study was to determine the surgical indications and risk factors for complications of third molar surgery at a Nigerian teaching hospital. Materials and Methods: Medical records of patients referred to the Oral Surgery Clinic of our institution for surgical extraction of their impacted mandibular third molars from January 2008 to December 2010 were retrospectively examined. Information on patients’ demography, types of impaction, operative parameters and complications were obtained and analyzed using Statistical Package for Social Sciences (SPSS Version 13), Chicago, IL, USA. A P < 0.0.5 was considered significant. Results: A total of 330 impacted teeth were extracted from 250 patients. Male comprises (104/250 [41.6%]) and female (146/250 [58.4%]). The mesioangular (176/330 [53.4%]) and distoangular (73/330 [22.1%]) impactions were the commonest types. Recurrent pericoronitis (154/330 [46.7%]) was the most common indication for extraction. The complications were delayed healing (19/330 [5.8%]), alveolar, osteitis (9/330 [2.7%]) and injury to alveolar nerve (2/330 [0.6%]). Cigarette smoking (P < 0.001), Oral contraceptives use (P = 0.01), age of the patient (P = 0.03) and the surgeon's experience (P = 0.04) were found to be significantly associated with the development of alveolar osteitis; nerves injuries were significantly associated with the raising of a lingual flap (P < 0.001) and the technique of surgery (P ≤ 0.001). Conclusion: The age of the patient, cigarette smoking and oral contraceptive use at the time of surgery are some of the factors affecting outcome in third molar surgery. PMID:25506490

  19. Comparative evaluation of molar distalization therapy using pendulum and distal screw appliances

    PubMed Central

    Cafagna, Alessandra; Fontana, Mattia; Cozzani, Mauro

    2015-01-01

    Objective To compare dentoalveolar and skeletal changes produced by the pendulum appliance (PA) and the distal screw appliance (DS) in Class II patients. Methods Forty-three patients (19 men, 24 women) with Class II malocclusion were retrospectively selected for the study. Twenty-four patients (mean age, 12.2 ± 1.5 years) were treated with the PA, and 19 patients (mean age, 11.3 ± 1.9 years) were treated with the DS. The mean distalization time was 7 months for the PA group and 9 months for the DS group. Lateral cephalograms were obtained at T1, before treatment, and at T2, the end of distalization. A Mann-Whitney U test was used for statistical comparisons of the two groups between T1 and T2. Results PA and DS were equally effective in distalizing maxillary molars (4.7 mm and 4.2 mm, respectively) between T1 and T2; however, the maxillary first molars showed less distal tipping in the DS group than in the PA group (3.2° vs. 9.0°, respectively). Moreover, significant premolar anchorage loss (2.7 mm) and incisor proclination (5.0°) were noted in the PA group, whereas premolar distal movement (1.9 mm) and no significant changes at the incisor (0.1°) were observed in the DS group. No significant sagittal or vertical skeletal changes were detected between the two groups during the distalization phase. Conclusions PA and DS seem to be equally effective in distalizing maxillary molars; however, greater distal molar tipping and premolar anchorage loss can be expected using PA. PMID:26258063

  20. Odontoblast response to cavity preparation with Er:YAG laser in rat molars: an immunohistochemical study.

    PubMed

    Shigetani, Yoshimi; Suzuki, Hironobu; Ohshima, Hayato; Yoshiba, Kunihiko; Yoshiba, Nagako; Okiji, Takashi

    2013-07-01

    This study aimed to examine the dynamics of odontoblast-lineage cells following cavity preparation with erbium:yttrium-aluminum-garnet (Er:YAG) laser in rat molars. Cavity preparation was made with Er:YAG laser in the mesial surface of the maxillary left first molar of 8-week-old Wistar rats. Contralateral first molar served as unirradiated control. Immediately, 6 and 12 h and 1, 2, 3, 5 and 7 days after the lasing (n = 5, each), specimens were collected and processed for immunohistochemistry for heat-shock protein (HSP)-25 and nestin as markers for odontoblast-lineage cells. Cell proliferation assay using bromodeoxyuridine (BrdU) labeling was also performed. Unirradiated teeth showed HSP-25- and nestin-immunoreactivity in odontoblasts. At 6-12 h after irradiation, the odontoblastic layer was disorganized and some of odontoblasts lost the immunoreactivity to HSP-25 and nestin. At 1-2 days, however, HSP-25- and nestin-immunoreactivities in the odontoblast layer showed a noticeable recovery, resulting in the rearrangement of odontoblast-like cells intensely immunoreactive to HSP-25 and nestin at 3-7 days. BrdU-positive cells showed a significant increase at 2 days (P < 0.05 vs. immediate previous time point; one-way analysis of variance and Scheffé post hoc test), peaked at 3 days and then decreased significantly (P < 0.05). It was concluded that under the present experimental condition in rat molars, cavity preparation with Er:YAG laser induced mild and reversible damage to odontoblasts. The reparative process was characterized by the rearrangement of HSP-25- and nestin-immunoreactive odontoblast-like cells, which took place subsequent to the odontoblastic layer disorganization with partial loss of these immunoreactivities. PMID:22736273

  1. Endodontic Treatment of Hypertaurodontic Mandibular Molar Using Reciprocating Single-file System: A Case Report.

    PubMed

    C do Nascimento, Adriano; A F Marques, André; C Sponchiado-Júnior, Emílio; F R Garcia, Lucas; M A de Carvalho, Fredson

    2016-01-01

    Taurodontism is a developmental tooth disorder characterized by lack of constriction in the cementoenamel junction and consequent vertical stretch of the pulp chamber, accompanied by apical displacement of the pulpal floor. The endodontic treatment of teeth with this type of morpho-anatomical anomaly is challenging. The purpose of this article is to report the successful endodontic treatment of a hypertaurodontic mandibular molar using a reciprocating single-file system. PMID:27320297

  2. Physiological distal drift in rat molars contributes to acellular cementum formation.

    PubMed

    Tsuchiya, Shinobu; Tsuchiya, Masahiro; Nishioka, Takashi; Suzuki, Osamu; Sasano, Yasuyuki; Igarashi, Kaoru

    2013-08-01

    Occlusal forces may induce the physiological teeth migration in humans, but there is little direct evidence. Rat molars are known to migrate distally during aging, possibly caused by occlusal forces. The purpose of this study was to determine if a reduction in occlusion would decrease teeth migration and affect associated periodontal structures such as cementum. To reduce occlusal forces, the right upper first molar (M1) in juvenile rats was extracted. The transition of the position of upper second molar (M2) and formation of M2 cementum was followed during aging. From the cephalometric analyses, upper M2 was located more anterior compared with the original position with aging after M1 extraction. Associated with this "slowing-down" of the physiological drift, cementum thickness on distal surface, but not on mesial surface, of M2 root was significantly increased. The accumulation of alizarin red as vital stain indicative of calcification, was observed in the distal cementum of M2 root only on the side of M1 extraction. Extraction of M1 that results in less functional loading, distinctly attenuates the physiological drift only in the upper dentition. The decreased physiological drift appears to activate acellular cementum formation only on distal surface of M2 root, perhaps due to reduced mechanical stress associated with the attenuated distal drift. In conclusion, the physiological distal drift in rat molars appears to be largely driven by the occlusal force and also affects the formation of acellular cementum. These findings provide additional direct evidence for an important role of occlusal forces in tooth migration. PMID:23775928

  3. Administration of bisphosphonate (ibandronate) impedes molar tooth movement in rabbits: A radiographic assessment

    PubMed Central

    Venkataramana, V.; Kumar, S. Sathesh; Reddy, B. Vishnuvardhan; Cherukuri, A. Sreekanth; Sigamani, K. Raja; Chandrasekhar, G.

    2014-01-01

    Introduction: Bisphosphonate (Bp)-ibandronate is a pharmacological agent, exhibits antiosteoclastic or antiresorptive activity and used to treat osteolytic or osteopenic disorders. BP-ibandronate may also interfere during orthodontic tooth movement. The aim of this study was to examine the influence of locally administered Bp-ibandronate on experimental tooth movement in rabbits. Materials and Methods: Twenty rabbits were divided into two groups- “10” served as Group-1 (control) and other “10” as Group-2 (experimental). Both groups received nickel-titanium closed coil springs with 100 g force between mandibular molar and incisors. Group-1 animals received 1 ml normal saline and Group-2 animals received ibandronate solution (0.3 mg/kg body weight) locally, mesial to the mandibular molar on the 1st, 7th, and 14th day of the experiment. A total of “40” lateral cephalograms were taken from both groups on the 1st and 21st day using a digital X-ray unit (Siemens X-ray systems, 300 mA Pleomophos analog, 2008, Germany). Individually, each animal's radiograph was traced manually and superimposed. The molar tooth movement was measured with the help of a standard metric scale. Results: The Student's t-test has been done to compare the mean values of Group-1 (4.650 ± 0.363) and Group-2 (2.030 ± 0.291) and the difference was statistically significant (P < 0.001). Conclusion: The retarded molar tooth movement was noticed in local drug administered rabbits, which could be beneficial in orthodontics to control the undesired tooth movement. PMID:25210364

  4. The Use of Intraosseous Screw for Upper Molar Distalization: A Case Report

    PubMed Central

    Polat-Özsoy, Ömür

    2008-01-01

    The use of implants has made a major change in orthodontic treatment mechanics. They have replaced conventional unaesthetic and compliance dependent extraoral appliances with well accepted intraoral mechanics. Implants can be used in molar and canine distalization, intrusion and in extraoral force applications. In the present case report, treatment of a case using an intermaxillary fixation screw (IMF) will be presented. The treatment results will be evaluated using pretreatment, post distalization and post treatment cephalometric radiographs and dental casts. PMID:19212521

  5. Piezosurgery for the Lingual Split Technique in Lingual Positioned Impacted Mandibular Third Molar Removal

    PubMed Central

    Ge, Jing; Yang, Chi; Zheng, Jiawei; Qian, Wentao

    2016-01-01

    Abstract The aim of this study was to evaluate the effect and safety of lingual split technique using piezosurgery for the extraction of lingual positioned impacted mandibular 3rd molars with the goal of proposing a more minimally invasive choice for this common surgery. Eighty-nine consecutive patients with 110 lingual positioned impacted mandibular 3rd molars requiring extraction were performed the lingual split technique using piezosurgery. One sagittal osteotomy line and 2 transverse osteotomy line were designed for lingual and occlusal bone removal. The success rate, operative time, postoperative outcome, and major complications (including nerve injury, mandible fracture, severe hematoma or edema, and severe pyogenic infection) were documented and analyzed. All impacted mandibular 3rd molars were successfully removed (110/110). The average time of operation was 14.6 minutes (ranged from 7 to 28 minutes). One hundred and seven extraction sites (97.3%) were primary healing. Pain, mouth opening, swelling, and PoSSe scores on postoperative 7-day were 0.34 ± 0.63, 3.88 ± 0.66(cm), 2.4 ± 0.2(cm), and 23.7 ± 5.9, respectively. There were 6 cases (5.5%) had lingual nerve disturbance and 3 cases (2.7%) developed inferior alveolar nerve impairment, and achieved full recovery within 2 months by neurotrophic drug treatment. Our study suggested piezosurgery for lingual split technique provided an effective way for the extraction of lingual positioned and deeply impacted mandibular 3rd molar. PMID:27015214

  6. High-Temperature CO2 Sorption on Hydrotalcite Having a High Mg/Al Molar Ratio.

    PubMed

    Kim, Suji; Jeon, Sang Goo; Lee, Ki Bong

    2016-03-01

    Hydrotalcites having a Mg/Al molar ratio between 3 and 30 have been synthesized as promising high-temperature CO2 sorbents. The existence of NaNO3 in the hydrotalcite structure, which originates from excess magnesium nitrate in the precursor, markedly increases CO2 sorption uptake by hydrotalcite up to the record high value of 9.27 mol kg(-1) at 240 °C and 1 atm CO2. PMID:26927529

  7. Unusual occurrence of accessory central cusp in the maxillary second primary molar.

    PubMed

    Nirmala, S V S G; Challa, Ramasubbareddy; Velpula, Lalitha; Nuvvula, Sivakumar

    2011-04-01

    Accessory cusp present on the occlusal surface may seldom pose problems. While its presence may not be a cause for alarm in most instances, it can sometimes lead to serious consequences if it is damaged. This case presents a rare finding of unilateral central accessory cusp seen on the occlusal surface of the maxillary left second primary molar and discusses the need for continuous dental surveillance and preventive measures. PMID:21957391

  8. Unusual occurrence of accessory central cusp in the maxillary second primary molar

    PubMed Central

    Nirmala, S.V.S.G; Challa, Ramasubbareddy; Velpula, Lalitha; Nuvvula, Sivakumar

    2011-01-01

    Accessory cusp present on the occlusal surface may seldom pose problems. While its presence may not be a cause for alarm in most instances, it can sometimes lead to serious consequences if it is damaged. This case presents a rare finding of unilateral central accessory cusp seen on the occlusal surface of the maxillary left second primary molar and discusses the need for continuous dental surveillance and preventive measures. PMID:21957391

  9. Ameloblastoma after surgical removal of an impacted mandibular molar. A case report.

    PubMed

    Chindia, M L; Guthua, S W; Mwaniki, D L

    1991-04-01

    A case of an ameloblastoma diagnosed about 3 1/2 years after removal of an impacted mandibular 3rd molar is presented. The pre-operative radiographs, though poor in quality, showed an ill-defined radiolucency in relation to the tooth. This feature was not apparent to the examiners at the time of first presentation. Despite unfavourable working conditions in developing countries, a high level of suspicion should be maintained to avoid serious sequelae at a later stage. PMID:2051052

  10. Non surgical predicting factors for patient satisfaction after third molar surgery

    PubMed Central

    Balaguer-Martí, José-Carlos; Aloy-Prósper, Amparo; Peñarrocha-Oltra, David

    2016-01-01

    Background In the third molar surgery, it is important to focus not only on surgical skills, but also on patient satisfaction. Classically studies have been focused on surgery and surgeon’s empathy, but there are non-surgical factors that may influence patient satisfaction. Material and Methods A cross-sectional study was performed on 100 patients undergoing surgical extractions of impacted mandibular third molars treated from October 2013 to July 2014 in the Oral Surgery Unit of the University of Valencia. A questionnaire (20 questions) with a 10-point Likert scale was provided. The questionnaire assessed the ease to find the center, the ease to get oriented within the center, the burocratic procedures, the time from the first visit to the date of surgical intervention, waiting time in the waiting room, the comfort at the waiting room, the administrative staff (kindness and efficiency to solve formalities), medical staff (kindness, efficiency, reliability, dedication), personal data care, clarity in the information received (about the surgery, postoperative care and resolution of the doubts), available means and state of facilities. Outcome variables were overall satisfaction, and recommendation of the center. Statistical analysis was made using the multiple linear regression analysis. Results Significant correlations were found between all variables and overall satisfaction. The multiple regression model showed that the efficiency of the surgeon and the clarity of the information were statistically significant to overall satisfaction and recommendation of the center. The kindness of the administrative staff, available means, the state of facilities and the comfort at the waiting room were statistically significant to the recommendation of the center. Conclusions Patient satisfaction directly depends on the efficiency of the surgeon and clarity of the clinical information received about the procedure. Appreciation of these predictive factors may help clinicians

  11. Molar Pregnancy Presents as Tubal Ectopic Pregnancy: A Rare Case Report

    PubMed Central

    Teerthanath, S; Jose, Varsha; Shetty, Jayaprakash

    2016-01-01

    The incidence of hydatidiform mole is 1 per 1000 pregnancies. The occurrence of hydatidiform mole in ruptured tubal pregnancy is very rare. We report an unusual case of molar pregnancy in the right fallopian tube which presented as an adherent adnexal mass. The present case conveys the importance of histological examination of products of conception which helps the pathologist to provide an appropriate diagnosis, thereby the clinician can offer appropriate counseling and follow up to the patient. PMID:26894078

  12. Molar Pregnancy Presents as Tubal Ectopic Pregnancy: A Rare Case Report.

    PubMed

    Beena, Devi; Teerthanath, S; Jose, Varsha; Shetty, Jayaprakash

    2016-01-01

    The incidence of hydatidiform mole is 1 per 1000 pregnancies. The occurrence of hydatidiform mole in ruptured tubal pregnancy is very rare. We report an unusual case of molar pregnancy in the right fallopian tube which presented as an adherent adnexal mass. The present case conveys the importance of histological examination of products of conception which helps the pathologist to provide an appropriate diagnosis, thereby the clinician can offer appropriate counseling and follow up to the patient. PMID:26894078

  13. Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars

    PubMed Central

    Sharma, Pranjal; Swamy, Dinesh Francis; Shashidara, R; Swamy, Elaine Barretto

    2015-01-01

    ABSTRACT Need for the study: The most important procedure for a successful endodontic treatment is the cleaning and shaping of the canal system. Understanding the internal anatomy of teeth provides valuable information to the clinician that would help him achieve higher clinical success during endodontic therapy. Aims: To evaluate by computed tomography—the internal anatomy of mandibular second primary molars with respect to the number of canals, cross-sectional shape of canals, cross-sectional area of canals and the root dentin thickness. Materials and methods: A total of 31 mandibular second primary molars were subjected to computed-tomographic evaluation in the transverse plane, after mounting them in a prefabricated template. The images, thus, obtained were analyzed using De-winter Bio-wizard® software. Results: All the samples demonstrated two canals in the mesial root, while majority of the samples (65.48%) demonstrated two canals in the distal root. The cross-sectional images of the mesial canals demonstrated a round shape, while the distal canals demonstrated an irregular shape. The root dentin thickness was highly reduced on the distal aspect of mesial and mesial aspect of distal canals. Conclusion: The mandibular second primary molars demonstrated wide variation and complexities in their internal anatomy. A thorough understanding of the complexity of the root canal system is essential for understanding the principles and problems of shaping and cleaning, determining the apical limits and dimensions of canal preparations, and for performing successful endodontic procedures. How to cite this article: Kurthukoti AJ, Sharma P, Swamy DF, Shashidara R, Swamy EB. Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars. Int J Clin Pediatr Dent 2015;8(3):202-207. PMID:26628855

  14. Molecular representation of molar domain (volume), evolution equations, and linear constitutive relations for volume transport.

    PubMed

    Eu, Byung Chan

    2008-09-01

    In the traditional theories of irreversible thermodynamics and fluid mechanics, the specific volume and molar volume have been interchangeably used for pure fluids, but in this work we show that they should be distinguished from each other and given distinctive statistical mechanical representations. In this paper, we present a general formula for the statistical mechanical representation of molecular domain (volume or space) by using the Voronoi volume and its mean value that may be regarded as molar domain (volume) and also the statistical mechanical representation of volume flux. By using their statistical mechanical formulas, the evolution equations of volume transport are derived from the generalized Boltzmann equation of fluids. Approximate solutions of the evolution equations of volume transport provides kinetic theory formulas for the molecular domain, the constitutive equations for molar domain (volume) and volume flux, and the dissipation of energy associated with volume transport. Together with the constitutive equation for the mean velocity of the fluid obtained in a previous paper, the evolution equations for volume transport not only shed a fresh light on, and insight into, irreversible phenomena in fluids but also can be applied to study fluid flow problems in a manner hitherto unavailable in fluid dynamics and irreversible thermodynamics. Their roles in the generalized hydrodynamics will be considered in the sequel. PMID:19044872

  15. Accuracy of Cameriere's third molar maturity index in assessing legal adulthood on Serbian population.

    PubMed

    Zelic, Ksenija; Galic, Ivan; Nedeljkovic, Nenad; Jakovljevic, Aleksandar; Milosevic, Olga; Djuric, Marija; Cameriere, Roberto

    2016-02-01

    At the moment, a large number of asylum seekers from the Middle East are passing through Serbia. Most of them do not have identification documents. Also, the past wars in the Balkan region have left many unidentified victims and missing persons. From a legal point of view, it is crucial to determine whether a person is a minor or an adult (≥18 years of age). In recent years, methods based on the third molar development have been used for this purpose. The present article aims to verify the third molar maturity index (I3M) based on the correlation between the chronological age and normalized measures of the open apices and height of the third mandibular molar. The sample consisted of 598 panoramic radiographs (290 males and 299 females) from 13 to 24 years of age. The cut-off value of I3M=0.08 was used to discriminate adults and minors. The results demonstrated high sensitivity (0.96, 0.86) and specificity (0.94, 0.98) in males and females, respectively. The proportion of correctly classified individuals was 0.95 in males and 0.91 in females. In conclusion, the suggested value of I3M=0.08 can be used on Serbian population with high accuracy. PMID:26773223

  16. Inferior Alveolar Nerve Injury after Mandibular Third Molar Extraction: a Literature Review

    PubMed Central

    Juodzbalys, Gintaras

    2014-01-01

    ABSTRACT Objectives The purpose of this study was to systematically review the comprehensive overview of literature data about injury to the inferior alveolar nerve after lower third molar extraction to discover the prevalence of injury, the risk factors, recovery rates, and alternative methods of treatment. Material and Methods Literature was selected through a search of PubMed electronic databases. Articles from January 2009 to June 2014 were searched. English language articles with a minimum of 6 months patient follow-up and injury analysis by patient’s reporting, radiographic, and neurosensory testing were selected. Results In total, 84 literature sources were reviewed, and 14 of the most relevant articles that are suitable to the criteria were selected. Articles were analyzed on men and women. The influence of lower third molar extraction (especially impacted) on the inferior alveolar nerve was clearly seen. Conclusions The incidence of injury to the inferior alveolar nerve after lower third molar extraction was about 0.35 - 8.4%. The injury of the inferior alveolar nerve can be predicted by various radiological signs. There are few risk factors that may increase the risk of injury to the nerve such as patients over the age of 24 years old, with horizontal impactions, and extraction by trainee surgeons. Recovery is preferable and permanent injury is very rare. PMID:25635208

  17. Histopathological and radiographic evaluation of rat molar teeth after traumatic injury-a pilot study

    PubMed Central

    Prasanth, T; Saraswathi, TR

    2012-01-01

    Objective: Radiographic and histopathological evaluation of mechanical trauma on the development of maxillary molars in rat. Materials and Methods: Experimental study with 7-day-old five new born Wistar rats. Trauma induced on 7th postnatal day with #55 K file. Right first molar region of the maxilla was the experimental side, and the left side as control. Each animal was sacrificed for histopathological observation on 8th day (immediately next day of injury), 10th day (after 3 days of injury), 13th day (Enamel completion), 19th day (Emergence into oral cavity) and 42nd day when all the teeth came into functional occlusion. Results: On the 42nd day experimental side of the study, the 1st molar tooth had not erupted and the radiographs taken revealed conglomerate mass suggestive of complex odontome. Reduced tooth size, altered enamel and dentin formation, abscess formation and complex odontome like structure were observed histopathologically. Conclusion: The diversity of morphlogical and histopathological changes to intrusive force implies intricate mechanism involved in tooth development. PMID:23248457

  18. Replantation of Displaced Underlying Successor and Marsupialization of Radicular Cyst associated with a Primary Molar

    PubMed Central

    Ravi, GR

    2015-01-01

    ABSTRACT Radicular cysts are by far the most common cystic lesions of the jaw. However, those arising from primary teeth are comparatively rare, comprising only 0.5 to 3.3%. The aim of this paper is to present clinical, radiographic and histopathological characteristics of radicular cyst associated with a primary mandibular molar causing unusual displacement of the permanent successor. Extraction of primary tooth along with extirpation of cyst was done under local anesthesia. The displaced premolar was also extracted and then replanted in the socket after proper alignment. Healing was uneventful and the space of missing primary molar was maintained by band and loop space maintainer. The relationship between intracanal medicaments and rapid growth of cyst, as mentioned in literature was observed in our case too. Thus, pulpotomy treated primary teeth should receive periodic postoperative radiographic examination and absence of clinical symptoms does not mean that a pulpotomy treated tooth is healthy. How to cite this article: Lamba G, Ravi GR. Replantation of Displaced Underlying Successor and Marsupialization of Radicular Cyst associated with a Primary Molar. Int J Clin Pediatr Dent 2015;8(1):70-74. PMID:26124586

  19. Histological evaluation of pulp tissue from second primary molars correlated with clinical and radiographic caries findings

    PubMed Central

    Gopinath, Vellore Kannan; Anwar, Khurshid

    2014-01-01

    Background: Managing dental caries in young children is demanding due to the elusions present on the right diagnostic criteria for treatment. The present study evaluated the histological status of pulp tissues extracted from primary second molar with caries involvement. Histological findings are correlated with clinical and radiographic assessment. Materials and Methods: Simple experimental study was conducted on upper or lower second primary molars with occlusal (22 teeth) or proximal (22 teeth) dental caries. Selected children were below 6 years of age. Percentage of caries involvement, residual dentin thickness (RDT), radiographic assessment of interradicular and periapical areas, clinical caries depth and signs and symptoms are the parameters considered for comparing with the histological findings. The specimens were grouped based on the nature of the inflammatory process as acute or chronic. The data were analyzed by Student t-test to compare histological types of inflammation with clinical parameters. P value < 0.05 was considered as significant. Results: Four cases revealed severe acute inflammation in coronal and relatively mild acute inflammation in radicular pulp. In the rest of the specimen coronal and radicular pulp had similar acute or chronic inflammatory changes. Histological evidence of pulpitis correlated with dental caries depth of ≥80%, RDT of ≤1 mm, radiographic rarefactions in the interradicular regions and symptoms of pain. Conclusion: Primary second molars with more than two-third caries involvement with symptoms of pain histologically showed inflammation of both coronal and radicular pulp tissues in all cases. PMID:24932190

  20. Histopathology of the pulp of primary molars with active and arrested dentinal caries.

    PubMed

    Di Nicolo, R; Guedes-Pinto, A C; Carvalho, Y R

    2000-01-01

    The purpose of this study was to compare the histological appearance of the pulp of human primary molars with active and arrested lesions. The sample consisted of 36 primary molars (18 with active lesions and 18 with arrested lesions) extracted from 35 children between 5 to 9 years of age. The histological diagnosis was classified in normal pulp, transitional stage, partial pulpitis, total pulpitis and total necrosis, and then subdivided in three subgroups: treatable, untreatable and questionable. Results showed that normal pulp or transitional stage (treatable category) was diagnosed in 50% of teeth with arrested lesions, compared to 11.1% of teeth with active lesions. Partial pulpitis (questionable category) was present in 38.8% with arrested lesions compared to 22.2% with active lesions. Total pulpitis and total necrosis (untreatable category) was diagnosed in 11.2% with arrested lesions compared to 66.7% with active lesions. The observed frequencies of histological categories between both groups were statistically significant (P < 0.05). Histologically, pulp reaction under active and arrested lesions in primary molars revealed the formation of a basophilic calcio-traumatic line at the junction of the primary and reparative dentin, formation of reparative dentin and a regular odontoblastic layer in 60% of the cases. Results indicated that the type of lesion (active or arrested) is a good indicator of the histological status of the pulp. PMID:11314352

  1. Retrieval of mandibular third molar tooth accidentally displaced in submandibular space: Series of two cases.

    PubMed

    Solanki, Ravinder; Khangwal, Monika; Kumar, Davender; Goel, Mahesh

    2016-01-01

    Displacement of tooth or root in submandibular or parapharyngeal spaces is one of the serious complications while extracting mandibular third molar by the general practitioners. Possibilities enhance in cases with extremely thin lingual plates. Moreover, there are no posterior fascial borders limiting the sublingual and submandibular spaces. In addition, no fascial border separates these spaces from the inferior parapharyngeal space. Thus, there is free communication between these spaces and tooth easily may dislodge into further spaces and lead to serious complications ahead. Patients may represent with pain and swelling of the submandibular region and sometimes the limitation in mouth opening when the patient had undergone an unsuccessful surgical procedure and third molar displacement into submandibular space. Two cases of such complications are presented ahead. On clinical examination, submandibular area on the left side of the mandible was tender on palpation. Panoramic radiographs elicited presence of a radiopaque mass similar to that of a tooth root. The computed tomography (CT) scan confirmed the presence of a high-density area in the submandibular region. Orthopantomography and cone beam CT in another patient revealed the displaced third molar in submandibular space. Patients were planned to retrieve the tooth under local anesthesia and the postoperative course was uneventful. PMID:27433055

  2. PrPc is temporospatially expressed in molar development of rats.

    PubMed

    Yoo, H I; Jang, S M; Kang, J H; Kim, M S; Koh, J T; Jung, J Y; Kim, W J; Oh, W M; Kim, S H

    2013-12-01

    Odontogenesis, tooth development, is derived from two tissue components: ectoderm and neural crest-derived mesenchyme. Cyto-differentiation of odontogenic cells during development involves time-dependent and sequential regulation of genetic programs. This study was conducted to detect molecules implicated in cyto-differentiation of developing molar germs of rats. Differential display-PCR revealed that PrP(c) was differentially expressed between cap/early bell-staged germs (maxillary 3rd molar germs) and root formation-staged germs (maxillary 2nd molar germs) at postnatal day 9. Both levels of PrP(c) mRNA and protein expression were higher in the root formation stage than the cap/early bell stage and increased in a time-dependent manner. Immunofluorescence revealed for the first time that PrP(c) was not localized in the enamel organ, but localized in dental follicular cells for the development of the periodontal ligament and cementum as well as odontoblasts, both of which are of neural crest origin. These results suggest that the physiological functions of the PrP(c) in tooth development may be implicated in the differentiation of neural crest-derived mesenchyme including the periodontal tissues for root formation rather than epithelial tissue. PMID:24127188

  3. Buccal Injection of 2% Lidocaine With Epinephrine for the Removal of Maxillary Third Molars

    PubMed Central

    Yadav, Sunil; Verma, Ajay; Sachdeva, Akash

    2013-01-01

    The aim of the study was to demonstrate if 2% lidocaine hydrochloride with 1 : 200,000 epinephrine could provide palatal anesthesia in maxillary tooth removal with a single buccal injection. The subjects included in the clinical study were those requiring extraction of the maxillary third molar of either side. For the purpose of comparison, the sample was randomly divided into 2 main groups: group 1 (study group) included 100 subjects who were to receive a single injection before extraction, and group 2 (control group) included 100 subjects who were to receive a single buccal injection and a single palatal injection before extraction. After 5 minutes the extraction was performed. All patients were observed for Faces Pain Scale during extraction and asked for the same on a 100-mm visual analog scale after extraction. According to visual analog scale and Faces Pain Scale scores, when maxillary third molar removal without palatal injection (study group) and with palatal injection (control group) were compared the difference was not statistically significant (P > .05). Removal of maxillary third molars without palatal injection is possible by depositing 2 mL of 2% lidocaine hydrochloride with 1 : 200,000 epinephrine to the buccal vestibule of the tooth. PMID:24010986

  4. Comparative evaluation of pro-inflammatory cytokine levels in pulpotomized primary molars.

    PubMed

    Ozdemir, Yasemin; Kutukculer, Necil; Topaloglu-Ak, Asli; Kose, Timur; Eronat, Cemal

    2015-06-01

    The present in vivo study was performed to investigate the levels of the pro-inflammatory cytokines, interleukin (IL)-1α, IL-6, and IL-8, in primary molars for which pulpotomy was clinically indicated, and to evaluate the success rates of three different pulpotomy agents employed for cariously (CExp) or mechanically exposed (MExp) primary molars. Forty-seven primary molars were classified as MExp or CExp according to the type of pulpal exposure. Pulp tissue was harvested and analyzed using enzyme-linked immunosorbent assay (ELISA). Subsequently, three pulpotomy agents-calcium hydroxide (CH), mineral trioxide aggregate (MTA), and formocresol (FC)-were applied randomly, and the outcome was observed radiographically for 18 months. Levels of IL-6 and IL-8 were significantly higher in CExp pulp than in MExp pulp (P < 0.05). In the CH pulpotomy group, MExp teeth showed a higher success rate than CExp teeth. There was no significant difference in success rate between MExp and CExp teeth in both the FC and MTA groups. The levels of IL-6 and IL-8 have the potential to become indicators of pulp status and can be monitored by researchers to make the prognosis of vital pulp therapies less uncertain. As MTA and FC yielded higher rates of success than CH in CExp teeth, the choice of pulpotomy agent appears to be important in this context. PMID:26062864

  5. Replantation of Displaced Underlying Successor and Marsupialization of Radicular Cyst associated with a Primary Molar.

    PubMed

    Lamba, Gagandeep; Ravi, G R

    2015-01-01

    Radicular cysts are by far the most common cystic lesions of the jaw. However, those arising from primary teeth are comparatively rare, comprising only 0.5 to 3.3%. The aim of this paper is to present clinical, radiographic and histopathological characteristics of radicular cyst associated with a primary mandibular molar causing unusual displacement of the permanent successor. Extraction of primary tooth along with extirpation of cyst was done under local anesthesia. The displaced premolar was also extracted and then replanted in the socket after proper alignment. Healing was uneventful and the space of missing primary molar was maintained by band and loop space maintainer. The relationship between intracanal medicaments and rapid growth of cyst, as mentioned in literature was observed in our case too. Thus, pulpotomy treated primary teeth should receive periodic postoperative radiographic examination and absence of clinical symptoms does not mean that a pulpotomy treated tooth is healthy. How to cite this article: Lamba G, Ravi GR. Replantation of Displaced Underlying Successor and Marsupialization of Radicular Cyst associated with a Primary Molar. Int J Clin Pediatr Dent 2015;8(1):70-74. PMID:26124586

  6. Periodontal Effects of a Transposed Versus a Conventional Flap in Mandibular Third Molar Extractions.

    PubMed

    Laurito, Domenica; Lollobrigida, Marco; Graziani, Filippo; Guerra, Fabrizio; Vestri, Annarita; De Biase, Alberto

    2016-05-01

    The aim of this study was to compare a transposed with a repositioned flap by assessing the periodontal effects on the second molar and primary healing after extraction of partially impacted lower third molars. A total of 24 patients requiring partially impacted mandibular wisdom tooth removal were enrolled in the study. The test group (n = 12) underwent a transposed flap procedure, whereas the control group (n = 12) underwent a repositioned flap procedure. Plaque index, probing depth, bleeding on probing, and width of keratinized tissue were recorded the day of surgery (T1) and after 60 days (T4). Wound dehiscence was assessed on the mesio-distal and bucco-lingual directions at days 2 (T2), 7 (T3), and T4. No significant differences have been observed in the periodontal parameters between the groups at T1 and T4 (P > 0.05). Similarly, no difference was found at T2, T3, and T4 in wound dehiscence incidence (P > 0.05). To date, no data exists on the use of transposed flaps in third molar surgery; thus a comparison of results cannot be done. Further studies with larger population are needed to investigate the potential advantages of this type of flap. PMID:27054424

  7. Effect of submucosal application of tramadol on postoperative pain after third molar surgery.

    PubMed

    Gönül, Onur; Satılmış, Tülin; Bayram, Ferit; Göçmen, Gökhan; Sipahi, Aysegül; Göker, Kamil

    2015-01-01

    The aim of this study was to evaluate the effectiveness of submucosal application of tramadol, for acute postoperative facial pain, following the extraction of impacted third molar teeth. This prospective, double-blind, randomised placebo-controlled study included 60 ASA I-II patients undergoing impacted third molar surgery under local anaesthesia. Following the surgical procedure, patients were randomly divided into two groups; group T (1 mg/kg tramadol) and group S (2-mL saline). Treatments were applied submucosally after surgery. Pain after extraction was evaluated using a visual analogue scale (VAS) 0.5, 1, 2, 4, 6, 12, 24, and 48 h postoperatively. The time at which the first analgesic drug was taken, the total analgesic dose used, and adverse tissue reactions were also evaluated. In group T, postoperative VAS scores were significantly lower compared to that in group S (p < 0.05). This study demonstrated that post-operative submucosal application of tramadol is an effective method for reducing acute post-operative facial pain after impacted third molar surgery. PMID:26467984

  8. Chemical characterization of high-molar-mass fractions in a Norway spruce knotwood ethanol extract.

    PubMed

    Smeds, Annika I; Eklund, Patrik C; Willför, Stefan M

    2016-10-01

    The low-molar-mass (LMM) fraction, only, i.e., the GC-eluting compounds, which are mainly lignans, has been characterized in Norway spruce knotwood hydrophilic extracts previously. Of this fraction, many lignans and sesquilignans and all GC peaks supposedly representing dilignans remain unidentified. In this work, dilignans and the GC non-eluting compounds (the high-molar mass fractions, HMM) were characterized in a 7-hydroxymatairesinol-reduced knotwood ethanol extract of Norway spruce by using several fractionation and analytical techniques. A methyl tert-butyl ether (MTBE) insoluble fraction of the extract contained mainly HMM material, of which the main part was shown to consist of lignan oligomers. The oligolignans (with a molar mass up to approximately 3700 Da) seemed to be linked by 55' bonds, some of them containing one or two guaiacylglycerol ether units linked to the lignan by βO4 or β5 bonds. Several oligolignans were identified or tentatively identified. The MTBE soluble fraction, which accounted for the major part (81%) of the extract, contained mainly LMM material (lignans, sesqui- and dilignans). The part of the HMM material in the MTBE soluble fraction that was easily isolable (2%) seemed to contain polymers of fatty acids and alcohols, resin acids, and sterols. PMID:27256310

  9. Nonsyndromic Bilateral Multiple Impacted Supernumerary Mandibular Third Molars: A Rare and Unusual Case Report

    PubMed Central

    Reddy, G. Siva Prasad; Reddy, G. V.; Krishna, I. Venkata; Regonda, Shravan Kumar

    2013-01-01

    A supernumerary tooth is that which is present additionally to the normal series and can be found in any region of the dental arch. An impacted tooth is defined as the one which is embedded in the alveolus, so that its eruption is prevented, or the tooth is locked in position by bone or the adjacent teeth. The occurrence of multiple supernumerary teeth in only one patient in the absence of an associated systemic condition or syndrome is considered as a rare phenomenon. The occurrence of supernumerary teeth in the lower molar region is rare. A prevalence of less than 2% of cases occurring in this region has been estimated. Their occurrence presents a clinical problem for orthodontists and oral surgeons. The cause, frequency, complications, and surgical operation of impacted teeth are always interesting subjects for study and research. An impacted tooth can result in caries, pulp disease, periapical and periodontal disease, temporomandibular joint disorder, infection of the fascial space, root resorption of the adjacent tooth, and even oral and maxillofacial tumours. The management of impacted wisdom teeth has changed over the past 20 years from removal of nonsymptomatic third molars to simple observation. The aim of this paper is to present a rare case of bilateral multiple impacted supernumerary mandibular third molars. PMID:23476818

  10. A new method for determining the 3D spatial orientation of molar microwear.

    PubMed

    Tausch, Jeremy; Kullmer, Ottmar; Bromage, Timothy G

    2015-01-01

    Many types of behavioral and dietary information can be extracted from studies of tooth microwear. Some studies have even been successful at determining the overall directionality of microwear in order to establish gross masticatory movement (Williams et al., 2009, PNAS, 106, 11194-11199). However, microwear has never been successfully visualized in situ in 3 dimensions (3D), visualized virtually and quantified. The ability to accomplish this yields information on exact masticatory movement which can then be used to address any number of eco-biological and physiological questions in extant and extinct organisms. In order to create 3D virtual reality (VR) representation of microwear, fossil molars from the Javanese Sangiran 7 (S7) Homo erectus tooth collection and from historic hunter/gatherer meta-populations were imaged, the microwear in 3 dimensions was extracted, this information was then placed back on VR representations of the molars and quantified. The methodology contained herein demonstrates the efficacy and importance of such a technique in determining gross masticatory movement in fossil and recent hominin molars. This methodology could, in theory, be applied to any organism which produces microwear on its dentition. Applications in the fields of dentistry, orthodontics, climatology and dietary and habitat reconstructions can also be envisioned. PMID:26114579

  11. Retrieval of mandibular third molar tooth accidentally displaced in submandibular space: Series of two cases

    PubMed Central

    Solanki, Ravinder; Khangwal, Monika; Kumar, Davender; Goel, Mahesh

    2016-01-01

    Displacement of tooth or root in submandibular or parapharyngeal spaces is one of the serious complications while extracting mandibular third molar by the general practitioners. Possibilities enhance in cases with extremely thin lingual plates. Moreover, there are no posterior fascial borders limiting the sublingual and submandibular spaces. In addition, no fascial border separates these spaces from the inferior parapharyngeal space. Thus, there is free communication between these spaces and tooth easily may dislodge into further spaces and lead to serious complications ahead. Patients may represent with pain and swelling of the submandibular region and sometimes the limitation in mouth opening when the patient had undergone an unsuccessful surgical procedure and third molar displacement into submandibular space. Two cases of such complications are presented ahead. On clinical examination, submandibular area on the left side of the mandible was tender on palpation. Panoramic radiographs elicited presence of a radiopaque mass similar to that of a tooth root. The computed tomography (CT) scan confirmed the presence of a high-density area in the submandibular region. Orthopantomography and cone beam CT in another patient revealed the displaced third molar in submandibular space. Patients were planned to retrieve the tooth under local anesthesia and the postoperative course was uneventful. PMID:27433055

  12. Gross enamel hypoplasia in molars from subadults in a 16th-18th century London graveyard.

    PubMed

    Ogden, A R; Pinhasi, R; White, W J

    2007-07-01

    Dental Enamel Hypoplasia has long been used as a common nonspecific stress indicator in teeth from archaeological samples. Most researchers report relatively minor linear and pitted hypoplastic defects on tooth crown surfaces. In this work we report a high prevalence and early age of onset of extensive enamel defects in deciduous and permanent molars in the subadults from the post-medieval cemetery of Broadgate, east central London. Analysis of the dentition of all 45 subadults from the cemetery, using both macroscopic and microscopic methods, reveals disturbed cusp patterns and pitted, abnormal and arrested enamel formation. Forty-one individuals from this group (93.2%) showed some evidence of enamel hypoplasia, 28 of them showing moderate or extensive lesions of molars, deciduous or permanent (63.6% of the sample). Scanning Electron Microscope images reveal many molars with grossly deformed cuspal architecture, multiple extra cusps and large areas of exposed Tomes' process pits, where the ameloblasts have abruptly ceased matrix production, well before normal completion. This indented, rough and poorly mineralized surface facilitates both bacterial adhesion and tooth wear, and when such teeth erupt fully into the mouth they are likely to wear and decay rapidly. We suggest that this complex combination of pitted and plane-form lesions, combined with disruption of cusp pattern and the formation of multiple small cusps, should henceforth be identified as "Cuspal Enamel Hypoplasia." PMID:17492667

  13. Diagnosis and Management of a Patient with Congenitally Missing Maxillary First Permanent Molars: A Rare Case Report.

    PubMed

    Gupta, Megha; Panda, Suman; Mutawwam, Fahad Ahmed; Kariri, Fahad Musawi Mohammed

    2016-01-01

    Congenitally missing teeth are the most commonly seen dental anomalies. Agenesis of the permanent first molar has the least frequency of all the tooth types, and it usually occurs in association with oligodontia or anodontia. Thus, agenesis of the bilateral maxillary first permanent molar is an extremely rare occurrence, and no such case has been reported in ethnic Saudi Arabian population. We hereby report a case of nonsyndromic bilateral congenitally missing maxillary first permanent molar in an eight-year-old Saudi female patient. Comprehensive oral rehabilitation was done for the patient. The implications of the tooth agenesis are also discussed. The prognosis of this case is presented. PMID:27525130

  14. Does the Relationship between Retained Mandibular Third Molar and Mandibular Angle Fracture Exist? An Assessment of Three Possible Causes

    PubMed Central

    Duarte, Bruno G.; Assis, Diogo; Ribeiro-Júnior, Paulo; Gonçales, Eduardo Sanches

    2012-01-01

    The objective of this study is to discuss problems associated with dental retention through three clinical cases of mandible fractures related to the presence of retained lower third molars, emphasizing the possibility of mandible fractures resulting from this or from the extraction procedure. The three evaluated patients had a fracture in the mandible angle. The third molars were present in all the cases, as was the relationship of the fracture with the teeth. After evaluating the three cases and reviewing literature, it is believed that the presence of the retained lower third molars and the surgical procedures for their extraction increase the risk of mandible angle fractures. PMID:23997857

  15. Intraoral management of iatrogenically displaced lower third molar roots in the sublingual space: a report of 2 cases

    PubMed Central

    Zhao, Sufeng; Huang, Zheng; Geng, Tengyu; Huang, Lanzhu

    2015-01-01

    Surgical removal of the mandibular third molars is one of the most common procedures performed by dentists, as well as by oral and maxillofacial surgeons. Accidental displacement of teeth or roots into the fascial spaces, during surgical removal of the mandibular third molars, is a rare, but serious complication. Herein, we present 2 cases of iatrogenically displaced mandibular third molar roots into the sublingual space, which were successfully removed under local anesthesia intraorally. In addition to methods to minimize the risk of accidental tooth or root displacement, the importance of recognizing this complication and the methods of retrieval are also discussed. PMID:26770616

  16. Diagnosis and Management of a Patient with Congenitally Missing Maxillary First Permanent Molars: A Rare Case Report

    PubMed Central

    Panda, Suman; Kariri, Fahad Musawi Mohammed

    2016-01-01

    Congenitally missing teeth are the most commonly seen dental anomalies. Agenesis of the permanent first molar has the least frequency of all the tooth types, and it usually occurs in association with oligodontia or anodontia. Thus, agenesis of the bilateral maxillary first permanent molar is an extremely rare occurrence, and no such case has been reported in ethnic Saudi Arabian population. We hereby report a case of nonsyndromic bilateral congenitally missing maxillary first permanent molar in an eight-year-old Saudi female patient. Comprehensive oral rehabilitation was done for the patient. The implications of the tooth agenesis are also discussed. The prognosis of this case is presented. PMID:27525130

  17. Shape covariation between the craniofacial complex and first molars in humans

    PubMed Central

    Polychronis, Georgios; Halazonetis, Demetrios J

    2014-01-01

    The occurrence of mutual genetic loci in morphogenesis of the face and teeth implies shape covariation between these structures. However, teeth finalize their shape at an early age, whereas the face grows and is subjected to environmental influences for a prolonged period; it is therefore conceivable that covariation might modulate with age. Here we investigate the extent of this covariation in humans by measuring the 3D shape of the occlusal surface of the permanent first molars and the shape of the craniofacial complex from lateral radiographs, at two maturations stages. A sample of Greek subjects was divided into two groups (110 adult, 110 prepubertal) with equally distributed gender. The occlusal surfaces of the right first molars were 3D scanned from dental casts; 265 and 274 landmarks (including surface and curve semilandmarks) were digitized on the maxillary and mandibular molars, respectively. The corresponding lateral cephalometric radiographs were digitized with 71 landmarks. Geometric morphometric methods were used to assess shape variation and covariation. The vertical dimension of the craniofacial complex was the main parameter of shape variation, followed by anteroposterior deviations. The male craniofacial complex was larger (4.0–5.7%) and was characterized by a prominent chin and clockwise rotation of the cranial base (adult group only). Allometry was weak and statistically significant only when examined for the sample as a whole (percent variance explained: 2.1%, P = 0.0002). Covariation was statistically significant only between the lower first molar and the craniofacial complex (RV = 14.05%, P = 0.0099, and RV = 12.31%, P = 0.0162, for the prepubertal and adult groups, respectively). Subtle age-related covariation differences were noted, indicating that environmental factors may influence the pattern and strength of covariation. However, the main pattern was similar in both groups: a class III skeletal pattern (relative maxillary retrusion and

  18. A partial molar volume for ZnO in silicate melts.

    NASA Astrophysics Data System (ADS)

    Ledda, B.; Potuzak, M.; Dingwell, D. B.; Courtial, P.

    2004-12-01

    Trace elements in igneous petrology have, in comparison with major elements, a relevance in the petrogenetic modelling of magmatic differentiation that far outweighs their relative abundance. Optimal use of the information contained in trace element variations within igneous phases requires an accurate description of their partitioning behaviour as a function of phase composition and structure, as well as temperature and pressure. In this manner, the partial molar thermodynamic properties of trace elements in silicate melts may contribute to the petrogenetic modelling of such systems. With this in mind, a series of investigations into the partial molar properties of trace elements in silicate melts have been carried out in recent years. Here we extend this work to the analysis of the volumetric properties of ZnO in silicate melts. Densities of 8 Zn-bearing silicate melts have been determined in air in the temperature range of 1363 to 1850 K. The compositional joins investigated (sodium disilicate (NS2) - ZnO; anorthite-diopside 1 bar eutectic (AnDi) - ZnO; and diopside - petedunnite) were chosen based on the pre-existing experimental density data set, their petrological relevance and to provide a test for significant compositionally induced variations in the structural role of ZnO. The ZnO concentrations investigated range up to 25 mol% for sodium disilicate, 20 mol% for the anorthite-diopside 1 atm eutectic and 100 mol% petedunnite. Molar volumes and expansivities of all melts have been derived. The molar volumes of the present liquids all decrease with increasing ZnO content. The partial molar volume of ZnO derived here from the volumetric measurements for each binary system is the same within error. A multicomponent fit to the volumetric data for all compositions yields a value of 14.141(0.730) cm3.mol-1 at 1300 K. We find, herewith, no volumetric evidence for compositionally-induced coordination number variations for ZnO in alkali-bearing versus alkali

  19. Mouse molar morphogenesis revisited by three-dimensional reconstruction. II. Spatial distribution of mitoses and apoptosis in cap to bell staged first and second upper molar teeth.

    PubMed

    Lesot, H; Vonesch, J L; Peterka, M; Turecková, J; Peterková, R; Ruch, J V

    1996-10-01

    Tooth morphogenesis is a complex multifactorial process in which differential mitotic activities and cell death play important roles. Upper first (m1) and second (m2) molars from mouse embryos were investigated from early cap to bell stage. m2 differed from m1 by delayed origin of the enamel grooves delimiting the protrusion of the cap bottom towards the dental papilla, and retardation of the enamel knot formation. The width of the m2 enamel organ was conspicuously smaller during cap formation and length remained smaller throughout the period of observation. Formation of the cap depression was comparable in m1 and m2, however margins delimiting the enamel organ cavity arose in m1 and m2 as mirror images. Attempts were made to correlate changes in the distribution of apoptotic cells and bodies and/or mitoses with morphogenesis. These cellular activities were recorded from histological sections and represented in space using computer-assisted three-dimensional reconstructions. Mitoses in the epithelial compartment were associated with the development of the cervical loop. In the mesenchyme of m1 at early bell stage, a postero-anterior increasing gradient of mitoses was observed which might be correlated with the anterior growth of the molar. Cells in the enamel knot demonstrated a high level of apoptosis, retarded in m2, but absolutely no division. Apoptotic processes were also involved in the anterior delimitation of the m1 epithelium. Apoptosis might correspond to the programmed destruction of cells whose function had to be suppressed or whose potential activity had to be avoided. PMID:8946249

  20. Essentiality of Early Diagnosis of Molar Incisor Hypomineralization in Children and Review of its Clinical Presentation, Etiology and Management

    PubMed Central

    Jain, Abhay Kumar; Saha, Sonali; Singh, Jaspal

    2012-01-01

    Abstract Molar incisor hypomineralization (MIH) is a common developmental condition resulting in enamel defects in first permanent molars and permanent incisors. It presents at eruption of these teeth. One to four molars, and often also the incisors, could be affected. Since first recognized, the condition has been puzzling and interpreted as a distinct phenomenon unlike other enamel disturbances. Early diagnosis is essential since, rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. The purpose of this article is to review MIH and illustrate its diagnosis and clinical management in young children. How to cite this article: Garg N, Jain AK, Saha S, Singh J. Essentiality of Early Diagnosis of Molar Incisor Hypomineralization in Children and Review of its Clinical Presentation, Etiology and Management. Int J Clin Pediatr Dent 2012;5(3):190-196. PMID:25206166

  1. Comparison of antibacterial efficacy of intracanal medicaments in multiple visit pulpectomies in primary molars-an in vivo study.

    PubMed

    Lele, G S; Subba Reddy, V V

    2010-01-01

    Antibacterial efficacy of formocresol, 2% gluteraldehyde and iodine-potassium iodide was assessed by obtaining cultures at consecutive appointments in multiple visit pulpectomies in primary molars. Formocresol and 2% gluteraldehyde were more effective as intracanal medicaments and caused significant reduction in the counts of aerobic and anaerobic microorganisms, thereby supporting the need for placing intracanal medicaments with antibacterial properties, in multiple visit pulpectomies in primary molars. PMID:20215667

  2. Scanning electron microscopy of the three different types of cementum in the molar teeth of the guinea pig.

    PubMed

    Moriyama, Keita; Sahara, Noriyuki; Kageyama, Toru; Misawa, Yasuko; Hosoya, Akihiro; Ozawa, Hidehiro

    2006-06-01

    The aim of this study was to observe the three-dimensional distribution and structural characteristics of the three different types of cementum in the molar teeth of guinea pig by means of scanning electron microscopy. Twenty-five 4-week-old male guinea pigs were used in this study. Using decalcified and undecalcified specimens with or without NaOH maceration, we examined the mandibles, maxillae and extracted molars by scanning electron microscopy. Guinea pig molars consist of two longitudinal, deeply folded lamina cores covered by enamel on all surfaces, except the buccal surface of the upper molars and the lingual surface of the lower molars. In the regions without enamel, we observed continuous thin belt-like layers of conventional acellular cementum on the dentin surface. On the enamel-covered surfaces, two different types of coronal cementum were found: small circular islands of coronal cementum called cementum pearls, which were distributed widely at almost regular intervals on the peripheral enamel surface from the apical fifth to the occlusal surface; and cartilage-like cementum, which occupied almost all of the occlusal half of the two longitudinally folded grooves. The present study demonstrated the unique distribution pattern of the three different types of cementum in guinea pig molars. These cementum types may contribute to the requirements for many different functions such as mastication, anchorage and continuous tooth eruption. PMID:16620777

  3. 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

  4. Efficacy of CBCT for assessment of impacted mandibular third molars: a review – based on a hierarchical model of evidence

    PubMed Central

    Wenzel, A

    2015-01-01

    A radiographic examination of mandibular third molars is meant to support the surgeon in establishing a treatment plan. For years panoramic (PAN) imaging has been the first choice method; however, where an overprojection is observed between the third molar and the mandibular canal and when specific signs suggest a close contact between the molar and the canal, CBCT may be indicated. The present review provides an evaluation of the efficacy of CBCT for assessment of mandibular third molars using a six-tiered hierarchical model by Fryback and Thornbury in 1991. Levels 1–3 include studies on low evidence levels mainly regarding the technical capabilities of a radiographic method and the diagnostic accuracy of the related images. Levels 4–6 include studies on a higher level of evidence and assess the diagnostic impact of a radiographic method on the treatment of the patient in addition to the outcome for the patient and society including cost calculations. Only very few high-evidence studies on the efficacy of CBCT for radiographic examination of mandibular third molars exist and, in conclusion, periapical or PAN examination is sufficient in most cases before removal of mandibular third molars. However, CBCT may be suggested when one or more signs for a close contact between the tooth and the canal are present in the two-dimensional image—if it is believed that CBCT will change the treatment or the treatment outcome for the patient. Further research on high-evidence levels is needed. PMID:25135317

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

    PubMed

    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

  6. Comparative studies between mice molars and incisors are required to draw an overview of enamel structural complexity

    PubMed Central

    Goldberg, Michel; Kellermann, O.; Dimitrova-Nakov, S.; Harichane, Y.; Baudry, A.

    2014-01-01

    In the field of dentistry, the murine incisor has long been considered as an outstanding model to study amelogenesis. However, it clearly appears that enamel from wild type mouse incisors and molars presents several structural differences. In incisor, exclusively radial enamel is observed. In molars, enamel displays a high level of complexity since the inner part is lamellar whereas the outer enamel shows radial and tangential structures. Recently, the serotonin 2B receptor (5-HT2BR) was shown to be involved in ameloblast function and enamel mineralization. The incisors from 5HT2BR knockout (KO) mice exhibit mineralization defects mostly in the outer maturation zone and porous matrix network in the inner zone. In the molars, the mutation affects both secretory and maturation stages of amelogenesis since pronounced alterations concern overall enamel structures. Molars from 5HT2BR KO mice display reduction in enamel thickness, alterations of inner enamel architecture including defects in Hunter-Schreger Bands arrangements, and altered maturation of the outer radial enamel. Differences of enamel structure were also observed between incisor and molar from other KO mice depleted for genes encoding enamel extracellular matrix proteins. Thus, upon mutation, enamel analysis based exclusively on incisor defects would be biased. In view of the functional relationship between enamel structure and tooth morphogenesis, identification of molecular actors involved in amelogenesis requires comparative studies between mice molars and incisors. PMID:25285079

  7. Efficiency of noncompliance simultaneous first and second upper molar distalization: a three-dimensional tooth movement analysis.

    PubMed

    Mavropoulos, Anestis; Karamouzos, Andreas; Kiliaridis, Stavros; Papadopoulos, Moschos A

    2005-07-01

    Objective of this prospective study was the three-dimensional (3D) analysis of tooth movements after the noncompliance simultaneous distalization of the first and second maxillary molars. Ten patients (five girls and five boys; mean age: 13.2 years) with bilateral Class II molar relationships were treated with a noncompliance, fixed intraoral appliance. Upper second molars had already erupted in all cases. Dental casts and lateral cephalometric radiographs were taken immediately before placement and after removal of the appliance. The casts were 3D digitized and superimposed on a predefined area in the palate. The resulting holograms, as well as the cephalometric radiographs, were digitized and analyzed by means of customized cephalometric software. The whole procedure was repeated after a two- to four-week interval to estimate the error of both methods. The cast assessment of 3D sagittal and vertical tooth movements was more reliable than the cephalometric record. The average maxillary first molar distal movement was 2.8 mm. Anchorage loss was expressed by a 1.9-mm proclination of the central incisors. A substantial variation among patients and among the right and left side in the same patient was observed. Noncompliance simultaneous distalization of the first and second maxillary molars can be an efficient treatment option for the correction of Class II molar relationship. However, anchorage loss and individual variation have to be seriously considered. Bilaterally symmetrical effectiveness should not be relied upon. PMID:16097221

  8. Unique inhibitory cascade pattern of molars in canids contributing to their potential to evolutionary plasticity of diet

    PubMed Central

    Asahara, Masakazu

    2013-01-01

    Developmental origins that guide the evolution of dental morphology and dental formulae are fundamental subjects in mammalian evolution. In a previous study, a developmental model termed the inhibitory cascade model was established. This model could explain variations in relative molar sizes and loss of the lower third molars, which sometimes reflect diet, in murine rodents and other mammals. Here, I investigated the pattern of relative molar sizes (inhibitory cascade pattern) in canids, a taxon exhibiting a wide range of dietary habits. I found that interspecific variation in canid molars suggests a unique inhibitory cascade pattern that differs from that in murine rodents and other previously reported mammals, and that this variation reflects dietary habits. This unique variability in molars was also observed in individual variation in canid species. According to these observations, canid species have greater variability in the relative sizes of first molars (carnassials), which are functionally important for dietary adaptation in the Carnivora. In conclusion, an inhibitory cascade that differs from that in murine rodents and other mammals may have contributed to diverse dietary patterns and to their parallel evolution in canids. PMID:23467478

  9. Effect of non-erupted 3rd molars on distal roots and supporting structures of approximal teeth. A radiographic survey of 202 cases.

    PubMed

    Nemcovsky, C E; Libfeld, H; Zubery, Y

    1996-09-01

    Root resorption of 2nd molars in proximity to non-erupted 3rd molars has been widely reported. The purpose of this study was to determine the prevalence of root resorption in second molars adjacent to non-erupted third molars. Its association to age and gender of the patient, location and inclination of the non-erupted third molar and to distal bone support of the 2nd molars was analyzed. A radiographic survey of 202 periapical radiographs taken in patients with clinically missing third molars was conducted. 3 examiners independently evaluated the radiographs and only those cases where at least 2 observers agreed were included in this report. Statistical analysis was performed on 186 radiographs. Associations were analyzed with the Pearson chi 2 test. Radiographic evidence of root resorption was found in 45 2nd molars (24.2%) of which 12 (6.5%) showed moderate to complete root resorption. Non-erupted tooth apical position and mesio-inclination of 60 degrees or more relative to the distal root of the second molar were significantly associated with root resorption (p = 0.01368 and p = 0.0194, respectively). Resorption was positively associated with age of patient (p = 0.00606). These results may support early extraction of impacted 3rd molars especially in cases with a mesio-angulation of 60 degrees or more and an apical location in proximity to the distal root of the 2nd molar. PMID:8891930

  10. Retrospective study of root canal configurations of maxillary third molars in Central India population using cone beam computed tomography Part- I

    PubMed Central

    Rawtiya, Manjusha; Somasundaram, Pavithra; Wadhwani, Shefali; Munuga, Swapna; Agarwal, Manish; Sethi, Priyank

    2016-01-01

    Objective: The aim of this study was to investigate the root and canal morphology of maxillary third molars in Central India population using cone-beam computed tomography (CBCT) analysis. Materials and Methods: CBCT images of 116 maxillary third molars were observed, and data regarding the number of roots, the number of canals, and Vertucci's Classification in each root was statistically evaluated. Results: Majority of Maxillary third molars had three roots (55.2%) and three canals (37.9%). Most MB root (43.8%), DB root (87.5%), and palatal root (100%) of maxillary third molars had Vertucci Type I. Mesiobuccal root of three-rooted maxillary third molars had Vertucci Type I (43.8%) and Type IV (40.6%) configuration. Overall prevalence of C-shaped canals in maxillary third molars was 3.4%. Conclusion: There was a high prevalence of three-rooted maxillary molars with three canals. PMID:27011747

  11. Age estimation using lower permanent first molars on a panoramic radiograph: A digital image analysis

    PubMed Central

    Talabani, Ranjdar M.; Baban, Mohammed T.; Mahmood, Mohammed A.

    2015-01-01

    Objective: A study was carried out to analyze the efficacy and practical application for age estimation using digital panoramic radiograph to exploit image analysis to obtain metric measurement of morphological parameters of permanent mandibular first molar on Sulaimani population. Materials and Methods: In the present study a population of known age and sex was studied and subjected to digital panoramic radiographic examination. The correlation between the reduction of coronal pulp cavity and chronological age was examined in a sample of 96 individuals distributed into four age groups: 20-29 years (29 cases), 30-39 years (29 cases), 40-49 years (26 cases) and 50-59 years (12 cases). The height (mm) of the crown (CH = coronal height) and the height (mm) of coronal pulp cavity (CPCH = coronal pulp cavity height) of 96 of first molars from all subjects was measured. The tooth–coronal index (TCI) after Ikeda et al. was computed for each tooth and regressed on real age. Results: ANOVA was used to show the strength of relation between the age and TCI (P = 0.0000). The correlation coefficient (r2) was 0.49, which mean there is strong negative linear regression between age and TCI with the r2, regarding predicting age using TCI value, after the following equation calculated, Predicted age = 3.78 – (0.064 TCI) showed that there is no significant difference between real age and estimated age. Conclusion: There is a strong negative liner relationship between TCIs of mandibular first molars with chronological age of Sulaimani population, and age of individuals can therefore be estimated with a good degree of accuracy using regression equations. PMID:26005307

  12. Hyaluronan and hyaluronan synthases expression and localization in embryonic mouse molars.

    PubMed

    Yang, Guofeng; Jiang, Beizhan; Cai, Wenping; Liu, Shangfeng; Zhao, Shouliang

    2016-08-01

    Hyaluronan (HA) and hyaluronan synthases (HASs) have been shown to play critical roles in embryogenesis and organ development. However, there have not been any studies examining HA and HAS expression and localization during tooth development. The present study was designed to investigate the expression of HA and three isoforms of HASs (HAS1, 2, 3) in embryonic mouse molars. The first mandibular embryonic mouse molars were examined by immunohistochemistry at E11.5, E13.5, E14.5, E16.5, and E18.5. PCR and western blot analyses were performed on RNA and proteins samples from E13.5 to E18.5 tooth germs. At the initial stage (E11.5), HA and HASs were expressed in the dental epithelium but not the underlying dental mesenchyme. HA immunostaining gradually increased in the enamel organ from the bud stage (E13.5) to the late bell stage (E18.5), and HA and HASs were highly expressed in the stellate reticulum and stratum intermedium. HA immunostaining was also enhanced in the dental mesenchyme and its derived tissues, but it was not expressed in the ameloblast and odontoblast regions. The three HAS isoforms had distinct expression patterns, and they were expressed in the dental mesenchyme and odontoblast at various levels. Furthermore, HAS1 and HAS2 expression decreased, while HAS3 expression increased from E13.5 to E18.5. These results suggested that HA synthesized by different HASs is involved in embryonic mouse molar morphogenesis and cytodifferentiation. PMID:27318667

  13. Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation.

    PubMed

    Schultz, Julia A; Martin, Thomas

    2014-10-01

    Appearance of the tribosphenic molar in the Late Jurassic (160 Ma) is a crucial innovation for food processing in mammalian evolution. This molar type is characterized by a protocone, a talonid basin and a two-phased chewing cycle, all of which are apomorphic. In this functional study on the teeth of Late Jurassic Dryolestes leiriensis and the living marsupial Monodelphis domestica, we demonstrate that pretribosphenic and tribosphenic molars show fundamental differences of food reduction strategies, representing a shift in dental function during the transition of tribosphenic mammals. By using the Occlusal Fingerprint Analyser (OFA), we simulated the chewing motions of the pretribosphenic Dryolestes that represents an evolutionary precursor condition to such tribosphenic mammals as Monodelphis. Animation of chewing path and detection of collisional contacts between virtual models of teeth suggests that Dryolestes differs from the classical two-phased chewing movement of tribosphenidans, due to the narrowing of the interdental space in cervical (crown-root transition) direction, the inclination angle of the hypoflexid groove, and the unicuspid talonid. The pretribosphenic chewing cycle is equivalent to phase I of the tribosphenic chewing cycle, but the former lacks phase II of the tribosphenic chewing. The new approach can analyze the chewing cycle of the jaw by using polygonal 3D models of tooth surfaces, in a way that is complementary to the electromyography and strain gauge studies of muscle function of living animals. The technique allows alignment and scaling of isolated fossil teeth and utilizes the wear facet orientation and striation of the teeth to reconstruct the chewing path of extinct mammals. PMID:25091547

  14. Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation

    NASA Astrophysics Data System (ADS)

    Schultz, Julia A.; Martin, Thomas

    2014-10-01

    Appearance of the tribosphenic molar in the Late Jurassic (160 Ma) is a crucial innovation for food processing in mammalian evolution. This molar type is characterized by a protocone, a talonid basin and a two-phased chewing cycle, all of which are apomorphic. In this functional study on the teeth of Late Jurassic Dryolestes leiriensis and the living marsupial Monodelphis domestica, we demonstrate that pretribosphenic and tribosphenic molars show fundamental differences of food reduction strategies, representing a shift in dental function during the transition of tribosphenic mammals. By using the Occlusal Fingerprint Analyser (OFA), we simulated the chewing motions of the pretribosphenic Dryolestes that represents an evolutionary precursor condition to such tribosphenic mammals as Monodelphis. Animation of chewing path and detection of collisional contacts between virtual models of teeth suggests that Dryolestes differs from the classical two-phased chewing movement of tribosphenidans, due to the narrowing of the interdental space in cervical (crown-root transition) direction, the inclination angle of the hypoflexid groove, and the unicuspid talonid. The pretribosphenic chewing cycle is equivalent to phase I of the tribosphenic chewing cycle, but the former lacks phase II of the tribosphenic chewing. The new approach can analyze the chewing cycle of the jaw by using polygonal 3D models of tooth surfaces, in a way that is complementary to the electromyography and strain gauge studies of muscle function of living animals. The technique allows alignment and scaling of isolated fossil teeth and utilizes the wear facet orientation and striation of the teeth to reconstruct the chewing path of extinct mammals.

  15. Inactivation of Tgfbr2 in Osterix-Cre expressing Dental Mesenchyme Disrupts Molar Root Formation

    PubMed Central

    Coricor, George; MacDougall, Mary; Serra, Rosa

    2013-01-01

    It has been difficult to examine the role of TGF-ß in post-natal tooth development due to perinatal lethality in many of the signaling deficient mouse models. To address the role of Tgfbr2 in postnatal tooth development, we generated a mouse in which Tgfbr2 was deleted in odontoblast-and bone-producing mesenchyme. Osx-Cre;Tgfbr2fl/fl mice were generated (Tgfbr2cko) and postnatal tooth development was compared in Tgfbr2cko and control littermates. X-ray and μCT analysis showed that in Tgfbr2cko mice radicular dentin matrix density was reduced in the molars. Molar shape was abnormal and molar eruption was delayed in the mutant mice. Most significantly, defects in root formation, including failure of the root to elongate, were observed by postnatal day 10. Immunostaining for Keratin-14 (K14) was used to delineate Hertwig's epithelial root sheath (HERS). The results showed a delay in elongation and disorganization of the HERS in Tgfbr2cko mice. In addition, the HERS was maintained and the break up into epithelial rests was attenuated suggesting that Tgfbr2 acts on dental mesenchyme to indirectly regulate the formation and maintenance of the HERS. Altered odontoblast organization and reduced Dspp expression indicated that odontoblast differentiation was disrupted in the mutant mice likely contributing to the defect in root formation. Nevertheless, expression of Nfic, a key mesenchymal regulator of root development, was similar in Tgfbr2cko mice and controls. The number of osteoclasts in the bone surrounding the tooth was reduced and osteoblast differentiation was disrupted likely contributing to both root and eruption defects. We conclude that Tgfbr2 in dental mesenchyme and bone is required for tooth development particularly root formation. PMID:23933490

  16. Dentoskeletal features in individuals with ectopic eruption of the permanent maxillary first molar

    PubMed Central

    Rozzi, Matteo; Cardoni, Giulia; Ricchiuti, Maria Rosaria; Cozza, Paola

    2015-01-01

    Objective The aim of the study was to analyze the prevalence and distribution of ectopic eruption of the permanent maxillary first molar (EEM) in individuals scheduled for orthodontic treatment and to investigate the association of EEM with dental characteristics, maxillary skeletal features, crowding, and other dental anomalies. Methods A total of 1,317 individuals were included and randomly divided into two groups. The first 265 subjects were included as controls, while the remaining 1,052 subjects included the sample from which the final experimental EEM group was derived. The mesiodistal (M-D) crown width of the deciduous maxillary second molar and permanent maxillary first molar, maxillary arch length (A-PML), maxillomandibular transverse skeletal relationships (anterior and posterior transverse interarch discrepancies, ATID and PTID), maxillary and mandibular tooth crowding, and the presence of dental anomalies were recorded for each subject, and the statistical significance of differences in these parameters between the EEM and control groups was determined using independent sample t-tests. Chi-square tests were used to compare the prevalence of other dental anomalies between the two groups. Results The prevalence of maxillary EEM was 2.5%. The M-D crown widths, ATID and PTID, and tooth crowding were significantly greater, while A-PML was significantly smaller, in the EEM group than in the control group. Only two subjects showed an association between EEM and maxillary lateral incisor anomalies, which included agenesis in one and microdontia in the other. Conclusions EEM may be a risk factor for maxillary arch constriction and severe tooth crowding. PMID:26258065

  17. Mineral Trioxide Aggregate vs. Calcium Hydroxide in Primary Molar Pulpotomy: A Systematic Review

    PubMed Central

    Shirvani, Armin; Hassanizadeh, Raheleh; Asgary, Saeed

    2014-01-01

    Introduction: The aim of this quantitative systematic review/meta-analysis was to compare the treatment outcomes of mineral trioxide aggregate (MTA) and calcium hydroxide (CH) in pulpotomy of human primary molars. The focused PICO question was “in case of pulp exposure in vital primary molars, how does MTA pulpotomy compare to CH in terms of clinical/radiographic success?” Methods and Materials: We retrieved published randomized clinical trials (RCTs) of at least 6-month duration; our search included articles published up to March 2013 in five following databases: PubMed (Medline), Cochrane database of systematic reviews, Science Citation Index, EMBASE, and Google Scholar. Mantel Haenszel and Inverse Variance-weighted methods were applied by STATA; the relative risk (RR) was calculated with 95% confidence intervals (CI). Results: A total of 282 English articles were collected. Two authors independently screened the articles and five RCTs were selected; data extraction and quality assessment were then carried out. Four RCTs were appropriate for meta-analysis according to their follow-up times by Mantel Haenszel method. Statistically significant difference was found between success rate of MTA compared to CH, with RR=0.08 (95% CI, 0.02-0.39), RR=0.19 (95% CI, 0.08-0.46), and RR=0.38 (95% CI, 0.21-0.68) for 6-, 12-, and 24-month follow-ups, respectively. A significant difference was also observed for all included RCTs after analyses using the Inverse Variance-weighted method (RR=0.44; 95% CI, 0.27-0.72). Conclusions: Systematic review/meta-analysis of included RCTs revealed that for pulpotomy of vital primary molars, MTA has better treatment outcomes compared to CH. PMID:24688575

  18. Lipogenesis in Huh7 cells is promoted by increasing the fructose: Glucose molar ratio

    PubMed Central

    Windemuller, Fernando; Xu, Jiliu; Rabinowitz, Simon S; Hussain, M Mahmood; Schwarz, Steven M

    2016-01-01

    AIM: To determine whether hepatocyte lipogenesis, in an in vitro cell culture model, is modulated by adjusting culture media monosaccharide content and concentration. METHODS: Hepatocytes (Huh7), demonstrating glucose and fructose uptake and lipid biosynthesis, were incubated in culture media containing either glucose alone (0.65-0.72 mmol/L) or isosmolar monosaccharide (0.72 mmol/L) comprising fructose:glucose (F:G) molar ratios ranging from 0.58-0.67. Following a 24-h incubation, cells were harvested and analyzed for total protein, triglyceride (TG) and cholesterol (C) content. Significant differences (P < 0.05) among groups were determined using analysis of variance followed by Dunnett’s test for multiple comparisons. RESULTS: After a 24 h incubation period, Huh7 cell mass and viability among all experimental groups were not different. Hepatocytes cultured with increasing concentrations of glucose alone did not demonstrate a significant change either in C or in TG content. However, when the culture media contained increasing F:G molar ratios, at a constant total monosaccharide concentration, synthesis both of C and of TG increased significantly [F:G ratio = 0.58, C/protein (μg/μg) = 0.13; F:G = 0.67, C/protein = 0.18, P < 0.01; F:G ratio = 0.58, TG/protein (μg/μg) = 0.06; F:G ratio = 0.67, TG/protein = 0.11, P < 0.01]. CONCLUSION: In an in vitro hepatocyte model, glucose or fructose plus glucose support total cell mass and lipogenic activity. Increasing the fructose:glucose molar ratio (but not glucose alone) enhances triglyceride and cholesterol synthesis. These investigations demonstrate fructose promotes hepatocellular lipogenesis, and they provide evidence supporting future, in vivo studies of fructose’s role in the development of hepatic steatosis and non-alcoholic fatty liver disease. PMID:27458503

  19. Absolute silicon molar mass measurements, the Avogadro constant and the redefinition of the kilogram

    NASA Astrophysics Data System (ADS)

    Vocke, R. D., Jr.; Rabb, S. A.; Turk, G. C.

    2014-10-01

    The results of an absolute silicon molar mass determination of two independent sets of samples from the highly 28Si-enriched crystal (AVO28) produced by the International Avogadro Coordination are presented and compared with results published by the Physikalisch-Technische Bundesanstalt (PTB, Germany), the National Research Council (NRC, Canada) and the National Metrology Institute of Japan (NMIJ, Japan). This study developed and describes significant changes to the published protocols for producing absolute silicon isotope ratios. The measurements were made at very high resolution on a multi-collector inductively coupled plasma mass spectrometer using tetramethylammonium hydroxide (TMAH) to dissolve and dilute all samples. The various changes in the measurement protocol and the use of TMAH resulted in significant improvements to the silicon isotope ratio precision over previously reported measurements and in particular, the robustness of the 29Si/30Si ratio of the AVO28 material. These new results suggest that a limited isotopic variability is present in the AVO28 material. The presence of this variability is at present singular and therefore its significance is not well understood. Fortunately, its magnitude is small enough so as to have an insignificant effect on the overall uncertainty of an Avogadro constant derived from the average molar mass of all four AVO28 silicon samples measured in this study. The NIST results confirm the AVO28 molar mass values reported by PTB and NMIJ and confirm that the virtual element-isotope dilution mass spectrometry approach to calibrated absolute isotope ratio measurements developed by PTB is capable of very high precision as well as accuracy. The Avogadro constant NA and derived Planck constant h based on these measurements, together with their associated standard uncertainties, are 6.02214076(19) × 1023 mol-1 and 6.62607017(21) × 10-34 Js, respectively.

  20. Efficacy and Safety of 2% and 4% Articaine for Lower Third Molar Surgery.

    PubMed

    Senes, A M; Calvo, A M; Colombini-Ishikiriama, B L; Gonçalves, P Z; Dionísio, T J; Sant'ana, E; Brozoski, D T; Lauris, J R P; Faria, F A C; Santos, C F

    2015-09-01

    This double-blind crossover randomized clinical trial compared the efficacy of 2 concentrations of articaine, 2% (A2) and 4% (A4), with 1:200,000 epinephrine, for lower third molar removal. During 2 separate appointments with either A2 or A4, both similarly positioned lower third molars in 46 volunteers were extracted. The following were evaluated: onset and duration of anesthetic action on soft tissues, intraoperative bleeding, hemodynamic parameters, postoperative analgesia, and mouth opening and wound healing during the 7th postoperative day, along with the incidence, type, and severity of adverse reactions. Nearly identical volumes of both anesthetic solutions were used for each appointment: 3.4 ± 0.9 mL ≈ 68 mg of articaine (A2) and 3.3 ± 0.8 mL ≈ 132 mg of articaine (A4). Statistical analysis indicated no differences in onset or duration of anesthetic action on soft tissues or duration of postoperative analgesia evoked by A2 and A4 anesthetic solutions (P > 0.05). The surgeon's rating of intraoperative bleeding was considered minimal throughout all surgery with both anesthetic solutions. While transient changes in blood pressure, heart rate, and oxygen saturation were observed, these factors were clinically insignificant and were uninfluenced by articaine concentration (P > 0.05). No systemic or local adverse reactions were observed in the preoperative and postoperative periods due to A2 or A4, but 1 case of bilateral paresthesia was observed. There were no significant differences between preoperative and postoperative (7th day) values of mouth opening and wound healing whether volunteers received A2 or A4 (P > 0.05). In conclusion, both A2 and A4, administered in equal volumes, were effective and safe during lower third molar surgery, and no significant differences were found between their efficacy and safety (ClinicalTrials.gov NCT02457325). PMID:26202994

  1. Accuracy of an equation for estimating age from mandibular third molar development in a Thai population

    PubMed Central

    Verochana, Karune; Prapayasatok, Sangsom; Mahasantipiya, Phattaranant May; Korwanich, Narumanas

    2016-01-01

    Purpose This study assessed the accuracy of age estimates produced by a regression equation derived from lower third molar development in a Thai population. Materials and Methods The first part of this study relied on measurements taken from panoramic radiographs of 614 Thai patients aged from 9 to 20. The stage of lower left and right third molar development was observed in each radiograph and a modified Gat score was assigned. Linear regression on this data produced the following equation: Y=9.309+1.673 mG+0.303S (Y=age; mG=modified Gat score; S=sex). In the second part of this study, the predictive accuracy of this equation was evaluated using data from a second set of panoramic radiographs (539 Thai subjects, 9 to 24 years old). Each subject's age was estimated using the above equation and compared against age calculated from a provided date of birth. Estimated and known age data were analyzed using the Pearson correlation coefficient and descriptive statistics. Results Ages estimated from lower left and lower right third molar development stage were significantly correlated with the known ages (r=0.818, 0.808, respectively, P≤0.01). 50% of age estimates in the second part of the study fell within a range of error of ±1 year, while 75% fell within a range of error of ±2 years. The study found that the equation tends to estimate age accurately when individuals are 9 to 20 years of age. Conclusion The equation can be used for age estimation for Thai populations when the individuals are 9 to 20 years of age. PMID:27051633

  2. Evaluation of diagnostic accuracy and dimensional measurements by using CBCT in mandibular first molars

    PubMed Central

    Asgary, Saeed; Nikneshan, Sima; Akbarzadeh-Bagheban, Alireza

    2016-01-01

    Background This study aimed to assess the diagnostic accuracy of cone beam computed tomography (CBCT) and quantitatively evaluate the morphology of mandibular first molars using CBCT. Material and Methods Twenty-four double-rooted mandibular first molars were evaluated by NewTom VGi CBCT. The distance from the furcation and apex to the cementoenamel junction (CEJ), diameter and thickness of canal walls, the buccolingual (BL) to mesiodistal (MD) ratio (ΔD), prevalence of oval canals at different sections and taper of the canals were all determined. In order to assess the diagnostic accuracy of CBCT, distance from the furcation and apex to the CEJ and thickness of canal walls at the CEJ and apex were compared with the gold standard values (caliper and stereomicroscope). Statistical analyses were carried out using intraclass correlation coefficient (ICC), paired t-test and repeated measures ANOVA. Results A high correlation existed between the CBCT and gold standard measurements (P<0.001). In dimensional measurements, length of mesial root was higher than the distal root and lingual furcation was farther from the CEJ than the buccal furcation (P<0.001). An important finding of this study was the mesiodistal taper of the mesiobuccal (MB) and mesiolingual (ML) canals; which was equal to 0.02. Conclusions CBCT has acceptable diagnostic accuracy for measurement of canal wall thickness. Cleaning and shaping of the canals should be performed based on the unique anatomy of the respective canal; which necessitates the use of advanced imaging techniques for thorough assessment of root canal anatomy in a clinical setting. Key words:Permanent mandibular first molar, accuracy, cone-beam computed tomography, dimensional measurement. PMID:26855697

  3. Morphometric evaluation and planning of anticurvature filing in roots of maxillary and mandibular molars.

    PubMed

    Oliveira, Maria Antonieta Veloso Carvalho; Venâncio, Jessyca Figueira; Raposo, Luís Henrique Araújo; Barbosa Júnior, Nelson; Biffi, João Carlos Gabrielli

    2015-01-01

    This study aimed to guide the planning of anticurvature filing using pre-determined anatomical points on teeth to establish directions for proper implementation of the technique. Two hundred digital periapical radiographs of human molar teeth were selected and divided into two groups (n = 100): MX (maxillary) and MD (mandibular) molars. Mesiobuccal roots were considered for the MX group and mesial roots for the MD group. Pre-determined anatomical points required for planning the anticurvature filing on the root canal path were located, and the distances between these points obtained. The anticurvature filing was simulated in two different protocols for each group, and the region of dentin removal and the remaining dentin thickness were measured in the safety and danger zones of the root canals. Statistical analysis was carried out at a significance level of 5%. The distances between the anatomical points and the thickness of remaining dentin showed significant differences when the two groups were compared (p < 0.001). No significant differences were found between the two experimental groups regarding the area of dentin removal at the root region, but differences were detected in comparison with dentin removal at the crown (p < 0.001). In terms of wear produced after simulation of both anticurvature filing protocols, significant differences were verified for all regions, except for the dentin remaining at the danger zone. The radiographic location of anatomical points allows for planning and implementation of controlled and efficient anticurvature filing and can be performed in the same manner for maxillary and mandibular molars. PMID:25466326

  4. First molar eruption, weaning, and life history in living wild chimpanzees

    PubMed Central

    Smith, Tanya M.; Machanda, Zarin; Bernard, Andrew B.; Donovan, Ronan M.; Papakyrikos, Amanda M.; Muller, Martin N.; Wrangham, Richard

    2013-01-01

    Understanding dental development in chimpanzees, our closest living relatives, is of fundamental importance for reconstructing the evolution of human development. Most early hominin species are believed to show rapid ape-like patterns of development, implying that a prolonged modern human childhood evolved quite recently. However, chimpanzee developmental standards are uncertain because they have never been based on living wild individuals. Furthermore, although it is well established that first molar tooth emergence (movement into the mouth) is correlated with the scheduling of growth and reproduction across primates broadly, its precise relation to solid food consumption, nursing behavior, or maternal life history is unknown. To address these concerns we conducted a photographic study of subadult chimpanzees (Pan troglodytes schweinfurthii) in Kanyawara, Kibale National Park, Uganda. Five healthy infants emerged their lower first molars (M1s) by or before 3.3 y of age, nearly identical to captive chimpanzee mean ages (∼3.2 y, n = 53). First molar emergence in these chimpanzees does not directly or consistently predict the introduction of solid foods, resumption of maternal estrous cycling, cessation of nursing, or maternal interbirth intervals. Kanyawara chimpanzees showed adult patterns of solid food consumption by the time M1 reached functional occlusion, spent a greater amount of time on the nipple while M1 was erupting than in the preceding year, and continued to suckle during the following year. Estimates of M1 emergence age in australopiths are remarkably similar to the Kanyawara chimpanzees, and recent reconstructions of their life histories should be reconsidered in light of these findings. PMID:23359695

  5. Effect of submucosal and intramuscular dexamethasone on postoperative sequelae after third molar surgery: comparative study.

    PubMed

    Majid, Omer Waleed; Mahmood, Waseem Khalid

    2011-12-01

    We compared the effects of dexamethasone sodium phosphate given submucosally and intramuscularly on postoperative complications after removal of impacted lower third molars in a preliminary randomised prospective clinical trial. Thirty patients, each of whom required removal of a single impacted mandibular third molar under local anaesthesia, were randomly allocated to one of 3 groups of 10 each. The 2 experimental groups were given dexamethasone 4 mg submucosally or intramuscularly, and the control group had no steroid. Facial swelling and maximal interincisal distance were measured by an independent examiner at baseline (preoperatively), and at 1, 3, and 7 days postoperatively. Pain was measured by counting the number of rescue analgesic tablets taken, and from the patients' response to a visual analogue scale (VAS). The mean age of the 16 men and 14 women was 27 years (range 20-48). Both dexamethasone groups showed significant reductions in swelling (p<0.001) and in pain (p<0.05) compared with the control group at all intervals. Submucosal dexamethasone resulted in significantly less trismus than controls on day 1 postoperatively (p=0.04), but there were no significant differences among the groups at the other times. The effects of the two routes of dexamethasone were comparable for all variables. There were no cases of alveolar osteitis or wound infection. Dexamethasone 4 mg given submucosally is an effective way of minimising swelling, trismus, and pain after removal of impacted lower third molars, and is comparable with the intramuscular route. It offers a simple, safe, painless, non-invasive, and cost-effective treatment in moderate and severe cases. PMID:21035237

  6. Stepwise Excavation Allows Apexogenesis in Permanent Molars with Deep Carious Lesions and Incomplete Root Formation.

    PubMed

    Hernandéz-Gatón, Patrícia; Serrano, César Ruiz; Nelson Filho, Paulo; De Castañeda, Esther Ruiz; Lucisano, Marília P; Silva, Raquel A B da; Silva, Léa A B da

    2015-01-01

    This study evaluated the stepwise excavation technique in 138 permanent molars with deep carious lesions and incomplete root formation within a 24-month clinical and radiographic follow-up period. In 96.7% of the cases, success was observed (no pain, integrity of restoration margins, absence of radiographic alterations and apexogenesis). The cases of failure (3.3%) were due to the loss of the temporary restoration. In conclusion, the stepwise excavation is a promising technique for permanent teeth with deep carious lesions and incomplete root formation as a minimally invasive approach because it allows the preservation of pulp vitality and occurrence of apexogenesis. PMID:26655853

  7. Note: Nonpolar solute partial molar volume response to attractive interactions with water

    NASA Astrophysics Data System (ADS)

    Williams, Steven M.; Ashbaugh, Henry S.

    2014-01-01

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  8. Note: Nonpolar solute partial molar volume response to attractive interactions with water

    SciTech Connect

    Williams, Steven M.; Ashbaugh, Henry S.

    2014-01-07

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  9. Endodontic management of a mandibular first molar with six root canal systems

    PubMed Central

    Jain, Dilip; Reddy, Smitha; Venigalla, Bhuvan Shome; Kamishetty, Shekhar

    2015-01-01

    Internal anatomy of pulp is complex. The first mandibular molars typically have two roots, one mesial with two root canals and another distal root, which contains one or two canals. A 20-year-old female patient reported with intermittent pain and incomplete root canal treatment in left lower back region since 1-week. Refined access cavity revealed initially two canals in mesial and two canals in the distal root. With operating microscope and cone beam computerized tomography, two additional canals (L-mesio-buccal and B-mesio-lingual) were identified in mesial root. One-year follow-up showed patient was asymptomatic and complete healing of periapical radiolucency. PMID:26430309

  10. Sinus floor augmentation at the time of maxillary molar extraction: technique and report of preliminary results.

    PubMed

    Fugazzotto, P A

    1999-01-01

    A technique is described for accomplishing both localized sinus augmentation and guided bone regeneration at the time of maxillary molar extraction. One hundred nine sites were treated in 92 patients. Of these, 102 procedures (94.0%) were successful and 7 (6.0%) were partially successful. Success was defined as the ability to ideally position an implant at least 10 mm in length and 4.8 mm in width without perforating the floor of the sinus or generating an implant fenestration or dehiscence. Partially successful procedures required an additional osteotome sinus lift at the time of implant placement. PMID:10453669

  11. Molar Volume Modeling of Ti-Al-Nb and Ti-Al-Mo Ternary Systems

    NASA Astrophysics Data System (ADS)

    Zhu, Jun; Zhang, Chuan; Cao, Weisheng; Chen, Shuanglin; Zhang, Fan; Park, Joon Sik; Yi, Seonghoon

    2015-08-01

    Molar volume modeling was performed for both Ti-Al-Nb and Ti-Al-Mo ternary systems based on the thermodynamic modeling of these two systems. Comparison between the calculated phase equilibria and the experimental data proved the accuracy of thermodynamic modeling. With the calculated density contour curves superimposed on the equilibrium phase diagram, it provides a map for alloy developers to identify the promising alloy compositions that satisfy both the phase stability and density requirements and rule out those that fail to meet the requirements.

  12. [Combined analgetic drug treatment with ibuprofen after 3rd molar osteotomy].

    PubMed

    Schmelzeisen, R; Buchweitz, I K; Fricke, A; Frölich, J

    1990-01-01

    In a placebo-controlled double-blind study using 3 x 400 mg ibuprofen during the surgical removal of impacted and dislocated third molars, a pain reduction of 64% (p = 0.05) as against the placebo control group could be demonstrated on the day of surgery and the first postoperative day. In view of the published results of a double-blind study on the reduction of cheek swelling using dexamethasone, the perioperative combination of 3 x 600 mg ibuprofen with 2 x 6 mg dexamethasone seems to be helpful in reliably preventing pain and swelling after dental surgery. PMID:2135254

  13. Endodontic management of a mandibular first molar with six root canal systems.

    PubMed

    Jain, Dilip; Reddy, Smitha; Venigalla, Bhuvan Shome; Kamishetty, Shekhar

    2015-01-01

    Internal anatomy of pulp is complex. The first mandibular molars typically have two roots, one mesial with two root canals and another distal root, which contains one or two canals. A 20-year-old female patient reported with intermittent pain and incomplete root canal treatment in left lower back region since 1-week. Refined access cavity revealed initially two canals in mesial and two canals in the distal root. With operating microscope and cone beam computerized tomography, two additional canals (L-mesio-buccal and B-mesio-lingual) were identified in mesial root. One-year follow-up showed patient was asymptomatic and complete healing of periapical radiolucency. PMID:26430309

  14. A clinical and histopathological study of radicular cysts associated with primary molars.

    PubMed

    Mass, E; Kaplan, I; Hirshberg, A

    1995-11-01

    Radicular cysts originating from primary teeth are considered rare. The study analyzed 49 primary molars with radiolucent lesions ranging from 4-15 mm in diameter. 73.5% of the lesions were diagnosed as radicular cysts, and 26.5% as granulomas. The lesions were more frequent in the mandible. All lesions were associated with severely decayed teeth and only 4 had previous pulp therapy. The present study and the survey of the literature suggest that radicular cysts associated with primary teeth are not rare. PMID:8600282

  15. Robotic-assisted Laparoscopic Management of Chemoresistant Myoinvasive Complete Molar Pregnancy.

    PubMed

    Riley, Kristin; Newell, Jordan; Zaino, Richard; Kesterson, Joshua

    2015-01-01

    Postmolar malignant conditions are rare after evacuation of a complete molar pregnancy. Both medical and surgical management have a role in the treatment of persistent gestational trophoblastic neoplasia. Treatment decisions must account for the natural history of the disease, previous therapies, site of disease, and the patient's desire for uterine preservation. We report on a woman who presented with chemotherapy-refractory persistent gestational trophoblastic disease (GTD). She was found to have isolated, persistent trophoblastic tissue within the uterine myometrium. She underwent a robotic-assisted laparoscopic hysterectomy with curative results. Minimally invasive surgical management may be an option for treatment of women with isolated myoinvasive GTD. PMID:26009277

  16. Danger zone in mandibular molars before instrumentation: an in vitro study.

    PubMed

    Garcia Filho, Paulo Ferreira; Letra, Ariadne; Menezes, Renato; Carmo, Antônio Márcio Rezende do

    2003-12-01

    The aim of this work was to measure the danger zone in mandibular molars, relating to strip perforations that might affect the mesial root during canal instrumentation. One hundred mesial roots were sectioned 2mm below the furcation and the distal concavities were measured with a microscope from the border of the canals to the outer dentin of the root. The average thickness of the danger zone of the mesial roots was 0.789 +/- 0.182mm. No significant statistical differences were observed comparing the danger zone of mesiobuccal and mesiolingual canals. PMID:21394408

  17. Significance of Radiological Variables Studied on Orthopantamogram to Pridict Post-Operative Inferior Alveoler Nerve Paresthesia After Third Molar Extraction

    PubMed Central

    Mishra, Nitin; Rastogi, Madhur Kant; Sharma, Shalini

    2014-01-01

    Context: Removal of impacted third molar is a procedure that is often associated with post-operative complications. The rate of complications is somewhat high because of its proximity to the vital structures. Inferior alveolar nerve paresthesia is one of the common complications of impacted their molar surgery. This is due to intimate relationship between roots of mandibular third molar and inferior alveolar canal. To access the proximity of inferior alveolar canal to third molar many diagnostic methods are suggested but in conventional radiography orthopantamogram is considered as the best. There are many findings onorthopantamogram that are suggestive of close proximity of nerve to the canal. In this study authors reviewed seven radiographic findings related to proximity of roots to the inferior alveolar nerve as seen on orthopantamogram and try to find a relationship between these radiographic variables and presence of post-operative paresthesia. Study Design: The study containd 100 impacted third molars need to be removed. Presence of radiographic findings on orthopantamogram were noted and analyzed, to find a relationship with occurrence of post-operative inferior alveolar nerve paresthesia. Materials and Methods: This study comprises of 100 impacted third molar teeth indicated for extraction. Cases were randomly selected from the patients, needs to undergo extraction of impacted mandibular third molar. After extraction cases were evaluated for occurrence of inferior alveolar nerve paresthesia. Stastical Analyisis: Data was transferred to SPss 21 software for frequency calculation, and two tailed p-values were obtained betweens these variables and post-operative paresthesia, by applying Fischer’s exact test (GRAPH PAD SOFTWARE). Results: Out of seven, four radiological findings that are grooving of roots, hooked roots, bifid roots and obliteration of white line are significantly related to post-operative paresthesia while bending of canal, narrow canal and

  18. Economic and health implications of routine CBCT examination before surgical removal of the mandibular third molar in the Danish population

    PubMed Central

    Olsen, K R; Matzen, L H; Vaeth, M; Wenzel, A

    2015-01-01

    Objectives: This epidemiological study aimed to analyse economical and societal consequences in Denmark if CBCT is used routinely as a diagnostic method before removal of the mandibular third molar. Furthermore, the aim was to calculate the excess cancer incidence from this practice. Methods: 17 representative dental clinics in the regions of Denmark were visited by two observers, who registered the total number of patients in each clinic, the number of removed mandibular third molars from patients' files together with the age and gender of these patients. The data were collected from 2008 to 2014. The total number of removed mandibular third molars in Denmark each year was derived from the collected data and information on patients' contacts with dentists from Statistics Denmark as a sum of contributions from each region. The contribution of a region was obtained as the number of removed mandibular third molars in the selected clinics in the region times the ratio of the number of patients in the selected clinics in the region to the total number of patients with contact to a general practitioner in the region in 2011. Existing knowledge on the costs for panoramic and CBCT imaging was used to calculate total costs. The cancer incidence was calculated from lifetime attributable risk curves based on linear risk assumptions. Results: The selected clinics included 109,686 patients, and 1369 mandibular third molars had been surgically removed. Using data from Statistics Denmark gave an estimated annual number of removed mandibular third molars of 36,882 at a total cost of €6,633,400. The additional cancer incidence was estimated to be approximately 0.46 per year. Conclusions: The data should be used in a cost-effectiveness analysis of the clinical efficacy of CBCT imaging before removal of mandibular third molars. PMID:25785820

  19. The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses and Aluminate Solutions - 13099

    SciTech Connect

    Reynolds, Jacob G.

    2013-07-01

    Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOHNaAl(OH){sub 4}-H{sub 2}O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H{sub 2}O, NaOH, and NaAl(OH){sub 4} are determined. The equivalence of the CSLM and the graphical method is verified by comparing results determined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components. (authors)

  20. Abrasive, Silica Phytoliths and the Evolution of Thick Molar Enamel in Primates, with Implications for the Diet of Paranthropus boisei

    PubMed Central

    Rabenold, Diana; Pearson, Osbjorn M.

    2011-01-01

    Background Primates—including fossil species of apes and hominins—show variation in their degree of molar enamel thickness, a trait long thought to reflect a diet of hard or tough foods. The early hominins demonstrated molar enamel thickness of moderate to extreme degrees, which suggested to most researchers that they ate hard foods obtained on or near the ground, such as nuts, seeds, tubers, and roots. We propose an alternative hypothesis—that the amount of phytoliths in foods correlates with the evolution of thick molar enamel in primates, although this effect is constrained by a species' degree of folivory. Methodology/Principal Findings From a combination of dietary data and evidence for the levels of phytoliths in plant families in the literature, we calculated the percentage of plant foods rich in phytoliths in the diets of twelve extant primates with wide variation in their molar enamel thickness. Additional dietary data from the literature provided the percentage of each primate's diet made up of plants and of leaves. A statistical analysis of these variables showed that the amount of abrasive silica phytoliths in the diets of our sample primates correlated positively with the thickness of their molar enamel, constrained by the amount of leaves in their diet (R2 = 0.875; p<.0006). Conclusions/Significance The need to resist abrasion from phytoliths appears to be a key selective force behind the evolution of thick molar enamel in primates. The extreme molar enamel thickness of the teeth of the East African hominin Paranthropus boisei, long thought to suggest a diet comprising predominantly hard objects, instead appears to indicate a diet with plants high in abrasive silica phytoliths. PMID:22163299

  1. The component slope linear model for calculating intensive partial molar properties /application to waste glasses and aluminate solutions

    SciTech Connect

    Reynolds, Jacob G.

    2013-01-11

    Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOH-NaAl(OH){sub 4}-H{sub 2}O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H{sub 2}O, NaOH, and NaAl(OH){sub 4} are determined. The equivalence of the CSLM and the graphical method is verified by comparing results determined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components.

  2. Quadrupole terms in the Maxwell equations: Born energy, partial molar volume, and entropy of ions

    NASA Astrophysics Data System (ADS)

    Slavchov, Radomir I.; Ivanov, Tzanko I.

    2014-02-01

    A new equation of state relating the macroscopic quadrupole moment density {seriesshape Q} to the gradient of the field ∇E in an isotropic fluid is derived: {seriesshape Q} = αQ(∇E - {series U}∇.E/3), where the quadrupolarizability αQ is proportional to the squared molecular quadrupole moment. Using this equation of state, a generalized expression for the Born energy of an ion dissolved in quadrupolar solvent is obtained. It turns out that the potential and the energy of a point charge in a quadrupolar medium are finite. From the obtained Born energy, the partial molar volume and the partial molar entropy of a dissolved ion follow. Both are compared to experimental data for a large number of simple ions in aqueous solutions. From the comparison the value of the quadrupolar length LQ is determined, LQ = (αQ/3ɛ)1/2 = 1-4 Å. Data for ion transfer from aqueous to polar oil solution are analyzed, which allowed for the determination of the quadrupolarizability of nitrobenzene.

  3. MOLAR: Modular Linux and Adaptive Runtime Support for HEC OS/R Research

    SciTech Connect

    Frank Mueller

    2009-02-05

    MOLAR is a multi-institution research effort that concentrates on adaptive, reliable,and efficient operating and runtime system solutions for ultra-scale high-end scientific computing on the next generation of supercomputers. This research addresses the challenges outlined by the FAST-OS - forum to address scalable technology for runtime and operating systems --- and HECRTF --- high-end computing revitalization task force --- activities by providing a modular Linux and adaptable runtime support for high-end computing operating and runtime systems. The MOLAR research has the following goals to address these issues. (1) Create a modular and configurable Linux system that allows customized changes based on the requirements of the applications, runtime systems, and cluster management software. (2) Build runtime systems that leverage the OS modularity and configurability to improve efficiency, reliability, scalability, ease-of-use, and provide support to legacy and promising programming models. (3) Advance computer reliability, availability and serviceability (RAS) management systems to work cooperatively with the OS/R to identify and preemptively resolve system issues. (4) Explore the use of advanced monitoring and adaptation to improve application performance and predictability of system interruptions. The overall goal of the research conducted at NCSU is to develop scalable algorithms for high-availability without single points of failure and without single points of control.

  4. Ex vivo evaluation of caries infiltration after different application times in primary molars.

    PubMed

    Soviero, V M; Paris, S; Leal, S C; Azevedo, R B; Meyer-Lueckel, H

    2013-01-01

    Low viscosity resins (infiltrants) have been shown to penetrate the lesion body of natural caries lesions almost completely in vitro. However, penetration depths (PD) have not been evaluated in vivo. Therefore, the aim of the present study was to evaluate the penetration of an infiltrant into proximal caries lesions in primary molars after different application times using an ex vivo model. 59 proximal lesions from 34 children were randomly allocated to one of the application times and were infiltrated under clinical conditions for 1, 3, or 5 min. After extraction or exfoliation (n = 48), teeth were sectioned perpendicular to their surfaces and lesion depths (LD) as well as lesion areas (LA) were evaluated using polarized light microscopy. PD and penetration areas (PA) were measured on scanning electron microscopic images. Percentage penetration depth (PPD) and percentage penetration area (PPA) were calculated. The mean (±SD) LD and LA were 596 ± 203 µm and 4.03 ± 2.75 × 10(5) µm(2), respectively. PPD ranged from 70 to 80% and PPA from 54 to 60%. Longer application times did not result in significantly deeper or more complete penetration (p > 0.05; ANOVA). In conclusion, proximal caries lesions in primary molars can be infiltrated in vivo to a similar extent as observed previously in vitro. Moreover, 1-min application of the infiltrant led to PD and homogeneity similar to those observed with longer application times up to 5 min. PMID:23207512

  5. Primary and secondary closure technique following removal of impacted mandibular third molars: A comparative study

    PubMed Central

    Chaudhary, Manoj; Singh, Manpreet; Singh, Sanjay; Singh, S. P.; Kaur, Gagandeep

    2012-01-01

    Aim: The purpose of this study was to evaluate and compare the post operative healing, using primary versus second closure techniques after impacted mandibular third molar removal. Materials and Methods: The study consisted of twelve patients, Seven males and five females under 30 years of age were divided into two groups as Group A and Group B in the randomized fashion. In the Group A, closure was done by primary intention and in the Group B, by secondary closure. A comparison between both groups was done with a follow-up period of 6 h to 6 days with regards to postoperative pain and swelling. Results: The statistical analysis (analysis of variance for repeated measures, P < 0.05) showed that pain was greater in Group A, although it decreased over time similarly in the two groups. Pain and swelling was less severe with secondary healing than with primary healing. Conclusion: The outcome of this study suggested that secondary closure technique is better than primary closure technique for removal of impacted mandibular third molar with regards to postoperative pain and swelling. PMID:23251051

  6. Bubble curves and saturated liquid molar volumes for chlorofluorohydrocarbon-hydrocarbon mixtures: Experimental data and modeling

    SciTech Connect

    Laugier, S. ); Richon, D.; Renon, H. . Lab. de Thermodynamique)

    1994-01-01

    Vapor-liquid equilibria and liquid densities were obtained using a static apparatus fitted with a variable-volume cell which was described in detail by Valtz et al. (1). Results are given at four temperatures for the binary systems butane--1,2,2-trichlorotrifluoroethane, pentane--1,2-dichloro-1,1,2,2-tetrafluoroethane, hexane--1,2-dichloro-1,1,2,2-tetrafluoroethane, heptane--1,12-trichloro-1,2,2-trifluoromethane, heptane--1,2-dichloro-1,1,2,2-tetrafluoroethane, and benzene--1,2-dichloro-1,1,2,2-tetrafluoroethane and the ternary system 1,2-dichloro-1,1,2,2-tetrafluoroethane--1,1,2-trichloro-1,2,2-trifluoromethane--heptane. The best simultaneous representation of pressures and saturated liquid molar volumes at a given temperature and liquid composition for these mixtures is obtained using either the Patel-Teja or Trebble-Bishnoi-Salim equation of state (TBS EOS) in either their standard or generalized form (maximum deviation 0.7% in pressure and 3.1% in saturated liquid molar volume with the TBS EOS).

  7. Hydrophobic hydration and the anomalous partial molar volumes in ethanol-water mixtures

    NASA Astrophysics Data System (ADS)

    Tan, Ming-Liang; Miller, Benjamin T.; Te, Jerez; Cendagorta, Joseph R.; Brooks, Bernard R.; Ichiye, Toshiko

    2015-02-01

    The anomalous behavior in the partial molar volumes of ethanol-water mixtures at low concentrations of ethanol is studied using molecular dynamics simulations. Previous work indicates that the striking minimum in the partial molar volume of ethanol VE as a function of ethanol mole fraction XE is determined mainly by water-water interactions. These results were based on simulations that used one water model for the solute-water interactions but two different water models for the water-water interactions. This is confirmed here by using two more water models for the water-water interactions. Furthermore, the previous work indicates that the initial decrease is caused by association of the hydration shells of the hydrocarbon tails, and the minimum occurs at the concentration where all of the hydration shells are touching each other. Thus, the characteristics of the hydration of the tail that cause the decrease and the features of the water models that reproduce this type of hydration are also examined here. The results show that a single-site multipole water model with a charge distribution that mimics the large quadrupole and the p-orbital type electron density out of the molecular plane has "brittle" hydration with hydrogen bonds that break as the tails touch, which reproduces the deep minimum. However, water models with more typical site representations with partial charges lead to flexible hydration that tends to stay intact, which produces a shallow minimum. Thus, brittle hydration may play an essential role in hydrophobic association in water.

  8. Effect of Fluoride and Simplified Adhesive Systems on the Bond Strength of Primary Molars and Incisors.

    PubMed

    Firoozmand, Leily Macedo; Noleto, Lawanne Ellen Carvalho; Gomes, Isabella Azevedo; Bauer, José Roberto de Oliveira; Ferreira, Meire Coelho

    2015-01-01

    The aim of this study was evaluate in vitro the influence of simplified adhesive systems (etch-and-rinse and self-etching) and 1.23% acidulated phosphate fluoride (APF) on the microshear bond strength (μ-SBS) of composite resins on primary molars and incisors. Forty primary molars and forty incisors vestibular enamel was treated with either the self-etching Clearfil SE Bond (CSE, Kuraray) or etch-and-rinse Adper Single Bond 2 (SB2, 3M/ESPE) adhesive system. Each group was subdivided based on the prior treatment of the enamel with or without the topical application of 1.23% APF. Thereafter, matrices were positioned and filled with composite resin and light cured. After storage in distilled water at 37 ± 1°C for 24 h, the specimens were submitted to μ-SBS in a universal testing machine. Kruskal-Wallis and Mann-Whitney tests (p < 0.05) showed that the prior application of 1.23% APF led to a significant reduction in bond strength. The type of adhesive exerted no significant influence bond strength. In the inter-group analysis, however, significantly bond strength reduction was found for the incisors when CSE was employed with APF. Adhesive failure was the most common type of fracture. The bond strength was affected by the prior application of 1.23% APF and type of tooth. PMID:26312974

  9. The Anxiolytic Effect of Midazolam in Third Molar Extraction: A Systematic Review

    PubMed Central

    Chen, Qi; Wang, Lufei; Ge, Lina; Gao, Yuan; Wang, Hang

    2015-01-01

    Purpose To assess the efficacy of midazolam for anxiety control in third molar extraction surgery. Methods Electronic retrievals were conducted in Medline (via PubMed, 1950-2013.12), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 3), Embase (via OVID 1974-2013.12), and the System for Information on Grey Literature in Europe (SIGLE). The bibliographies of relevant clinical trials were also checked. Randomized controlled trials satisfying the inclusion criteria were evaluated, with data extraction done independently by two well-trained investigators. Disagreements were resolved by discussion or by consultation with a third member of the review team. Results Ten studies were included, but meta-analysis could not be conducted because of the significant differences among articles. All but one article demonstrated that midazolam could relieve anxiety. One article demonstrated that propofol offered superior anxiolysis, with more rapid recovery than with midazolam. Compared with lorazepam and diazepam, midazolam did not distinctly dominate in its sedative effect, but was safer. Two articles used midazolam in multidrug intravenous sedation and proved it to be more effective than midazolam alone. Conclusion It was found, by comparison and analysis, that midazolam might be effective for use for anxiety control during third molar extraction and can be safely administered by a dedicated staff member. It can also be used with other drugs to obtain better sedative effects, but the patient’s respiratory function must be monitored closely, because multidrug sedation is also more risky. PMID:25849859

  10. A two-short-implant-supported molar restoration in atrophic posterior maxilla: A finite element analysis

    PubMed Central

    2016-01-01

    PURPOSE The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implants. Three 2SI models (NP-oblique, NP-vertical, and NP-horizontal) and four single implant models (RP and WP in a centered or cantilevered position) were used. Axial and oblique loadings were applied on the occlusal surface of the crown. The von Mises stress values were measured at the bone-implant, peri-implant bone, and implant/abutment complex. RESULTS The highest stress distribution at the bone-implant interface and the peri-implant bone was noticed in the RP group, and the lowest stress distribution was observed in the 2SI groups. Cantilevered position showed unfavorable stress distribution with axial loading. 2SI types did not affect the stress distribution in oblique loading. The number and installation positions of the implant, rather than the bone level, influenced the stress distribution of 2SIs. The implant/abutment complex of WP presented the highest stress concentration while that of 2SIs showed the lowest stress concentration. CONCLUSION 2SIs may be useful for achieving stable stress distribution on the surrounding bone and implant-abutment complex in the atrophic posterior maxilla. PMID:27555900

  11. A determination of the molar gas constant R by acoustic thermometry in helium

    NASA Astrophysics Data System (ADS)

    Gavioso, R. M.; Madonna Ripa, D.; Steur, P. P. M.; Gaiser, C.; Truong, D.; Guianvarc'h, C.; Tarizzo, P.; Stuart, F. M.; Dematteis, R.

    2015-10-01

    We have determined the acoustic and microwave frequencies of a misaligned spherical resonator maintained near the temperature of the triple point of water and filled with helium with carefully characterized molar mass M=≤ft(4.002 6032+/- 0.000 0015\\right) g mol-1, with a relative standard uncertainty {{u}\\text{r}}(M)=0.37× {{10}-6} . From these data and traceable thermometry we estimate the speed of sound in our sample of helium at {{T}\\text{TPW}}=273.16  K and zero pressure to be u02=≤ft(\\text{945} \\text{71}0.45+/- 0.85\\right)  m2 s-2 and correspondingly deduce the value R=≤ft(8.314 4743+/- 0.000 0088\\right)  J mol-1 K-1 for the molar gas constant. We estimate the value k=R/{{N}\\text{A}}=≤ft(1.380 650 8+/- 0.000 0015\\right)× {{10}-23}  J K-1 for the Boltzmann constant using the currently accepted value of the Avogadro constant NA. These estimates of R and k, with a relative standard uncertainty of 1.06  ×  10-6, are 1.47 parts in 106 above the values recommended by CODATA in 2010.

  12. A Structural Molar Volume Model for Oxide Melts Part III: Fe Oxide-Containing Melts

    NASA Astrophysics Data System (ADS)

    Thibodeau, Eric; Gheribi, Aimen E.; Jung, In-Ho

    2016-04-01

    As part III of this series, the model is extended to iron oxide-containing melts. All available experimental data in the FeO-Fe2O3-Na2O-K2O-MgO-CaO-MnO-Al2O3-SiO2 system were critically evaluated based on the experimental condition. The variations of FeO and Fe2O3 in the melts were taken into account by using FactSage to calculate the Fe2+/Fe3+ distribution. The molar volume model with unary and binary model parameters can be used to predict the molar volume of the molten oxide of the Li2O-Na2O-K2O-MgO-CaO-MnO-PbO-FeO-Fe2O3-Al2O3-SiO2 system in the entire range of compositions, temperatures, and oxygen partial pressures from Fe saturation to 1 atm pressure.

  13. Accuracy of Cameriere's cut-off value for third molar in assessing 18 years of age.

    PubMed

    De Luca, S; Biagi, R; Begnoni, G; Farronato, G; Cingolani, M; Merelli, V; Ferrante, L; Cameriere, R

    2014-02-01

    Due to increasingly numerous international migrations, estimating the age of unaccompanied minors is becoming of enormous significance for forensic professionals who are required to deliver expert opinions. The third molar tooth is one of the few anatomical sites available for estimating the age of individuals in late adolescence. This study verifies the accuracy of Cameriere's cut-off value of the third molar index (I3M) in assessing 18 years of age. For this purpose, a sample of orthopantomographs (OPTs) of 397 living subjects aged between 13 and 22 years (192 female and 205 male) was analyzed. Age distribution gradually decreases as I3M increases in both males and females. The results show that the sensitivity of the test was 86.6%, with a 95% confidence interval of (80.8%, 91.1%), and its specificity was 95.7%, with a 95% confidence interval of (92.1%, 98%). The proportion of correctly classified individuals was 91.4%. Estimated post-test probability, p was 95.6%, with a 95% confidence interval of (92%, 98%). Hence, the probability that a subject positive on the test (i.e., I3M<0.08) was 18 years of age or older was 95.6%. PMID:24365729

  14. Determination of sexual dimorphism via maxillary first molar teeth in Himachali population

    PubMed Central

    Singla, Swati; Gupta, Rakhi; Puri, Abhiney; Bansal, Sucheta; Singla, Smita; Nangia, Rajat

    2015-01-01

    Context: Sex determination of skeletal remains forms part of archaeological and medicolegal examinations. It is an aspect of forensic odontology. Forensic odontology primarily deals with identification, based on recognition of unique features present in an individual's dental structures. Correct sex determination limits the pool of missing persons to just one half of the population. Aim of Study: Purpose of this study is to evaluate the existence of sexual dimorphism and variation in left and right maxillary first molars using bucco-lingual and mesio-distal dimensions in population of Sirmour District, H.P. Materials and Methods: Base sample comprised 100 subjects (50 males and 50 females) of an age group ranging from 17 to 25 years. Statistical Analysis Used: Unpaired t-test. Results: It was observed that the comparison of mean values of bucco-lingual and mesio-distal parameters showed highly statistically significant differences between males and females, measured both intraorally and on study casts. There were no significant differences between the mean values of both the parameters on the left side as compared to right side. Conclusion: The study concludes that sexual dimorphism is population specific. Among Himachali people, mesio-distal dimensions and bucco-lingual dimensions of first molar can aid in sex determination. PMID:26005295

  15. The Prx1 Homeobox Gene is Critical for Molar Tooth Morphogenesis

    PubMed Central

    Mitchell, J.M.; Hicklin, D.M.; Doughty, P.M.; Hicklin, J.H.; Dickert, J.W.; Tolbert, S.M.; Peterkova, R.; Kern, M.J.

    2008-01-01

    The paired-related homeobox genes, Prx1 and Prx2, encode transcription factors critical for orofacial development. Prx1-/-/Prx2-/- neonates have mandibular hypoplasia and malformed mandibular incisors. Although the mandibular incisor phenotype has been briefly described (ten Berge et al., 1998, 2001; Lu et al., 1999), very little is known about the role of Prx proteins during tooth morphogenesis. Since the posterior mandibular region was relatively normal, we examined molar tooth development in Prx1-/-/Prx2-/- embryos to determine whether the tooth malformation is primary to the loss of Prx protein or secondary to defects in surrounding tissues. Three-dimensional (3D) morphological reconstructions demonstrated that Prx1-/-/Prx2-/- embryos had molar malformations, including cuspal changes and ectopic epithelial projections. Although we demonstrate that Prx1 protein is expressed only mesenchymally, 3D reconstructions showed important morphological defects in epithelial tissues at the cap and bell stages. Analysis of these data suggests that the Prx homeoproteins are critical for mesenchymal-epithelial signaling during tooth morphogenesis. PMID:16998126

  16. Morphological changes related to age in mesial root canals of permanent mandibular first molars.

    PubMed

    Gani, Omar A; Boiero, Claudio F; Correa, Carolina; Masin, Ivana; Machado, Ricardo; Silva, Emmanuel J N L; Vansan, Luiz Pascoal

    2014-01-01

    The aim of this study was to evaluate age-related morphological canal changes in mesial root canals of mandibular first molars of known ages. Fifty-six specimens were selected for this study and distributed into the following four age groups (n. 14): a) Group of children under 13 years, b) Group of adolescents (from 14 to 19 years), c) Group of young adults (from 20 to 39 years) and d) Group of older adults (over 40 years). The specimens were in perfect condition because after extraction they were carefully cleaned, sterilized, identified and stored in water. In order to improve the cleaning, they were placed in 1% sodium hypochlorite solution for four hours and rinsed in 10 vol. hydrogen peroxide for 8 hours. After that, a clearing technique was performed to illustrate root canal anatomy. Digitalized images of all samples were obtained by use of a stereomicroscope. Canals were noticeably simpler in older adults: they were sharply defined and narrow, sometimes too narrow. Calcification nuclei were not found and there were only a few remains of internuclear spaces. The canal system appeared cleaner, clearer and more sharply defined than in the other age groups. It may be concluded that there is a correlation between aging and morphological changes in the mesial root canals of mandibular first molars. PMID:25560687

  17. The chronology of second molar development in Brazilians and its application to forensic age estimation

    PubMed Central

    Pontual, Andrea dos Anjos; Beltrão, Rejane Targino; Beltrão, Ricardo Villar; Pontual, Maria Luiza dos Anjos

    2013-01-01

    Purpose This study investigated the possible correlation between the mineralization of the second molars and the chronological age of a sample population of the state of Paraiba, Brazil. Materials and Methods One thousand eight hundred fifty-four digitized panoramic images using a scanner of a private dental radiology service were obtained in six months. Of these, 457 were selected from patients aged 4.6 to 16 years who met certain criteria. The images were assessed twice by a radiologist with 5 years experience. A minimum interval of 30 days between the evaluations of the same patient was established. To analyze the relationship between chronological age, calcification level proposed by Demirjian et al in 1973, gender, and tooth, a multiple linear regression model was adjusted, taking age as the response variable (p<0.05). Results The gender and calcification level were significantly correlated with the age of the patients (p<0.05). There was a significant difference between the average age of the patients' upper teeth compared to the lower ones in both genders (p<0.05). The dental development occurred earlier in female individuals than in male ones, and there was no significant difference between the right and left second permanent molars. Conclusion It was observed that ethnic variables are related to certain parameters of age and sex identification in the Brazilian population, providing important information for forensic evaluations. PMID:23524859

  18. Health Technology Assessment of CEM Pulpotomy in Permanent Molars with Irreversible Pulpitis

    PubMed Central

    Yazdani, Shahram; Jadidfard, Mohammad-Pooyan; Tahani, Bahareh; Kazemian, Ali; Dianat, Omid; Alim Marvasti, Laleh

    2014-01-01

    Introduction: Teeth with irreversible pulpitis usually undergo root canal therapy (RCT). This treatment modality is often considered disadvantageous as it removes vital pulp tissue and weakens the tooth structure. A relatively new concept has risen which suggests vital pulp therapy (VPT) for irreversible pulpitis. VPT with calcium enriched mixture (VPT/CEM) has demonstrated favorable treatment outcomes when treating permanent molars with irreversible pulpitis. This study aims to compare patient related factors, safety and organizational consideration as parts of health technology assessment (HTA) of the new VPT/CEM biotechnology when compared with RCT. Materials and Methods: Patient related factors were assessed by looking at short- and long-term clinical success; safety related factors were evaluated by a specialist committee and discussion board involved in formulating healthcare policies. Organizational evaluation was performed and the social implications were assessed by estimating the costs, availability, accessibility and acceptability. The impact of VPT/CEM biotechnology was assessed by investigating the incidence of irreversible pulpitis and the effect of this treatment on reducing the burden of disease. Results: VPT/CEM biotechnology was deemed feasible and acceptable like RCT; however, it was more successful, accessible, affordable, available and also safer than RCT. Conclusion: When considering socioeconomic implications on oral health status and oral health-related quality of life of VPT/CEM, the novel biotechnology can be more effective and more efficient than RCT in mature permanent molars with irreversible pulpitis. PMID:24396372

  19. Evaluation of formocresol, calcium hydroxide, ferric sulfate, and MTA primary molar pulpotomies

    PubMed Central

    Yildiz, Esma; Tosun, Gul

    2014-01-01

    Objective: The aim of this study is to evaluate four different pulpotomy medicaments in primary molars. Materials and Methods: A total of 147 primary molars with deep caries were treated with four different pulpotomy medicaments (FC: formocresol, FS: ferric sulfate, CH: calcium hydroxide, and MTA: mineral trioxide aggregate) in this study. The criteria for tooth selection for inclusion were no clinical and radiographic evidence of pulp pathology. During 30 months of follow-up at 6-month intervals, clinical and radiographic success and failures were recorded. The differences between the groups were statistically analyzed using the Chi-square test and Kaplan-Meier analysis. Results: At 30 months, clinical success rates were 100%, 95.2%, 96.4%, and 85% in the FC, FS, MTA, and CH groups, respectively. In radiographic analysis, the MTA group had the highest (96.4%), and the CH group had the lowest success rate (85%). There were no clinical and radiographic differences between materials (P > 0.05). Conclusions: Although there were no differences between materials, only in the CH group did three teeth require extraction due to further clinical symptoms of radiographic failures during the 30-month follow-up period. None of the failed teeth in the other groups required extraction during the 30-month follow-up period. PMID:24966776

  20. Coronectomy of the mandibular third molar: Respect for the inferior alveolar nerve.

    PubMed

    Kouwenberg, A J; Stroy, L P P; Rijt, E D Vree-V D; Mensink, G; Gooris, P J J

    2016-05-01

    The aim of this study was to evaluate the outcomes of coronectomy as an alternative surgical procedure to complete removal of the impacted mandibular third molar in patients with a suspected close relationship between the tooth root(s) and the mandibular canal. A total of 151 patients underwent coronectomy and were followed up with clinical examinations and panoramic radiographs for a minimum of 6 months after surgery. None of the patients exhibited inferior alveolar nerve injury. Eruption of the retained root(s) was more frequent in younger patients (18-35 years). Thirty-six patients (23.8%) exhibited insufficient growth of new bone in the alveolar defect, and 11.3% required a second surgical procedure to remove the root remnant(s). Our results indicate that coronectomy can be a reliable alternative to complete removal of the impacted mandibular third molar in patients exhibiting an increased risk of damage to the inferior alveolar nerve on panoramic radiographs. PMID:26976696

  1. Evaluation of intra-alveolar chlorhexidine dressings after removal of impacted mandibular third molars.

    PubMed

    Fotos, P G; Koorbusch, G F; Sarasin, D S; Kist, R J

    1992-03-01

    Chlorhexidine gluconate (CHX) has been investigated for its possible benefit in the prevention of alveolar osteitis complicating third molar removal. In a double-blind, placebo-controlled clinical study, 70 randomly selected healthy patients were subjected to uncomplicated mandibular third molar removal followed by CHX-gelatin sponge and saline solution-gelatin sponge intra-alveolar dressings. Each patient was followed for 6 days for postoperative discomfort and complications, and scored accordingly. The results demonstrated that patients receiving 0.2% CHX intra-alveolar dressings exhibited a significant reduction in postoperative discomfort and complications when compared with saline solution-treated control sites (p less than 0.005). Further, this phenomenon was not found to be related to patient factors including age, sex, and race, nor did any correlation exist between treated or control sites, and surgical factors including performing surgeon, surgeon's dominant hand, time of surgery, surgical site, and difficulty of the removal. These findings warrant further studies concerning the apparent clinical benefit of postextraction intra-alveolar CHX dressings for the reduction of postoperative alveolar osteitis. PMID:1545974

  2. Efficiency of gaseous ozone in reducing the development of dry socket following surgical third molar extraction

    PubMed Central

    Ahmedi, Jehona; Ahmedi, Enis; Sejfija, Osman; Agani, Zana; Hamiti, Vjosa

    2016-01-01

    Objective: The objective of this study was to assess the efficacy of ozone gas (O3) on the reduction of dry socket (DS) occurrence following surgical extraction of lower jaw third molars, influence of the indication for the extraction, and the difficulty of extraction on the incidence of DS. Materials and Methods: This study included thirty patients with bilaterally impacted third molars of mandible requiring surgical procedure for extraction. Following extraction, in the control group, saline solution was used for irrigation of extraction sockets and in the experimental group, intra-alveolar O3 was applied for 12 s (Prozone, W and H, UK, Ltd.). The surgeries were performed by the same oral surgeon. The follow-up visits were performed at 48 h and on day seven, postsurgery where the symptoms of DS were evaluated and intensity of pain has been recorded using visual analog scale 0–100. Results: In this pilot study, DS was present in 16.67% and 3.33% of cases in the control and experimental groups, respectively (P = 0.20). Conclusion: The application of O3 may reduce the incidence of DS and accelerates the recovery period after the surgery. Prophylactic use of O3 may be suggested in all patients, especially in the patients at a risk of development of DS. PMID:27403058

  3. Comparison of platelet rich plasma and synthetic graft material for bone regeneration after third molar extraction

    PubMed Central

    Nathani, Dipesh B.; Sequeira, Joyce; Rao, B. H. Sripathi

    2015-01-01

    Aims: To compare the efficacy of Platelet rich plasma and synthetic graft material for bone regeneration after bilateral third molar extraction. Material and Methods: This study was conducted in 10 patients visiting the outpatient department of Oral & Maxillofacial Surgery, Yenepoya Dental College & Hospital. Patients requiring extraction of bilateral mandibular third molars were taken for the study. Following extraction, PRP (Platelet Rich Plasma) was placed in one extraction socket and synthetic graft material in form granules [combination of Hydroxyapatite (HA) and Bioactive glass (BG)] in another extraction socket. The patients were assessed for postoperative pain and soft tissue healing. Radiological assessment of the extraction site was done at 8, 12 and 16 weeks interval to compare the change in bone density in both the sockets. Results: Pain was less on PRP site when compared to HA site. Soft tissue evaluation done using gingival healing index given by Landry et al showed better healing on PRP site when compared to HA site. The evaluation of bone density by radiological assessment showed the grey level values calculated at 4 months at the PRP site were comparatively higher than HA site. Conclusion: The study showed that the platelet rich plasma is a better graft material than synthetic graft material in terms of soft tissue and bone healing. However a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of both the materials. PMID:26981473

  4. Morphological and clinical considerations of first and second permanent molar eruption disorders.

    PubMed

    Proff, Peter; Bayerlein, Thomas; Fanghänel, Jochen; Allegrini, Sergio; Gedrange, Tomas

    2006-07-01

    Tooth eruption is a complex biological process which starts from the site of development in the jaw bone until the teeth reach their final functional position in the chewing plane. Various factors can disturb this process. Besides mechanical obstacles on the eruption path, a pathological position or axial orientation of the tooth germ, morphological aberrations of the tooth or pathological alterations of the periodontium, primary disorders of the eruption mechanism may lead to complete or partial retention of the tooth in the jaw bone. These morphological features bear upon the prognosis of orthodontic correction which is dependent upon the underlying cause. First and second molars are rarely affected by eruption disorders, with a prevalence of 0.01 to 0.08 per cent, however, marked consequences for function such as posterior open bite or elongation of the antagonists may result. Following an overview of pathogenetic factors of tooth eruption disorders, selected cases of impacted first and second permanent molars are presented with respect to their morphological causes. PMID:16856600

  5. [Evaluation of postoperative mucosa and skin temperature after surgery for impacted third molar].

    PubMed

    Sortino, F; Messina, G; Pulvirenti, G

    2003-01-01

    Surgery for impacted third molar is often characterized, in the postoperative period, by pain, trismus and swelling. The study evaluates temperature variations of mucosa and skin after application of ice packs, in three different modalities, to the region overlying the surgical site. The goal was to identify any correlation between variations of temperature and postoperative clinical symptoms. For this purpose we selected 54 patients programmed for impacted third molar surgery. The patients were divided into three groups of 18. Time and frequency of application of the ice pack varied in the three groups; 5'/30' (group 1); 10'/60' (group 2); 20'/60' (group 3). During the four hours following surgery, temperatures of mucosa and of skin at the surgical site were measured with high-precision thermocouples, maximum response 5". The results indicate that application of an ice pack for 5'/30' or for 10'/60' controls the temperature of the mucosa post-surgery more effectively, and that the duration of surgery appears not to influence temperature variations. In the postoperative phase we recommend a rational application of ice packs appropriate to the constitution of each patient. PMID:14608260

  6. Calcium-Enriched Mixture Pulpotomy of Primary Molar Teeth with Irreversible Pulpitis. A Clinical Study

    PubMed Central

    Memarpour, Mahtab; Fijan, Soleiman; Asgary, Saeed; Keikhaee, Marzieh

    2016-01-01

    Objectives: To evaluate the outcome of vital pulp therapy in primary teeth with irreversible pulpitis by using calcium-enriched mixture (CEM) cement according to clinical and radiographic assessment. Participants and Methods: Fifty primary molar teeth with irreversible pulpitis in 50 children aged 6-8 years underwent pulpotomy using CEM cement as the dressing material. Following pulpotomy, pain intensity was evaluated by use of a visual analog scale at 1 and 7 days from the treatment and in clinical appointments at 3, 6 and 12 months after baseline. Radiographic evaluation was performed at 6 and 12 months. Data were analyzed using the McNemar test. Results: A total of 42 children (mean age 7.26 ± 0.82 year) completed the study. After one day treatment 56 % of children reported complete relief of pain and after 7 days 62% reported the same. However, two children complained of increased pain 1 day after treatment. None of the children reported pain in the subsequent appointments. One child complained of tenderness in percussion after 6 months. Pulp canal obliteration was the most common change in the radiographic assessment. There was no significant difference between clinical (92.8%) and radiographic (90.4%) success (p=0.990). Conclusion: Pulpotomy using CEM cement could present a successful treatment in primary molar teeth with irreversible pulpitis. PMID:27326265

  7. [Half-molar sodium-lactate: The osmotic agent we are looking for?].

    PubMed

    Aramendi, I; Manzanares, W; Biestro, A

    2016-03-01

    Intracranial hypertension (ICH) is the most important modifiable factor with predictive negative value in brain injury patients. Osmotherapy is the most important first level specific measure in the treatment of ICH. Mannitol 20%, and 3, 7.5, 10, and 23% hypertonic sodium chloride are the most commonly used osmotic agents in the neurocritical care setting. Currently, controversy about the best osmotic agent remains elusive. Therefore, over the past few years, half-molar sodium lactate has been introduced as a new osmotic agent to be administered in the critically ill. Lactate is able to prevent hyperchloremia, as well as its adverse effects such as hyperchloremic acidosis, systemic inflammation, and acute kidney injury. Furthermore, lactate may also be used by glia as energy substrate in brain injury patients. Half-molar sodium lactate would also have a more potent and long-lasting effect decreasing intracellular osmolarity and by inhibiting neuronal volume control mechanisms. Pioneering researches in patients with traumatic brain injury have shown a more significant effect than mannitol on the control of ICH. In addition, in this group of patients this solution appears to be beneficial in preventing episodes of ICH. However, future research is necessary to corroborate or not these promising results. PMID:26655973

  8. The maxillary molar endodontic access opening: A microscope-based approach

    PubMed Central

    Mamoun, John Sami

    2016-01-01

    This article reviews the basic clinical techniques of performing a maxillary molar endodontic access opening, starting from the initial access opening into the pulp chamber, to the point where a size #10 file has been advanced to the apices of all three or four (or more) canals. The article explains how the use of the dental surgical operating microscope or microscope-level loupes magnification of ×6–8 or greater, combined with head-mounted or coaxial illumination, improve the ability of a dentist to identify microscopic root canal orifices, which facilitates the efficient creation of conservative access openings with adequate straight-line access in maxillary molars. Magnified photos illustrate various microscopic anatomical structures or landmarks of the initial access opening. Techniques are explored for implementing an access opening for teeth with vital versus necrotic pulpal tissues. The article also explores the use of piezoelectric or ultrasonic instruments for revealing root canal orifices and for removing pulp stones or calcified pulpal tissue inside the pulp chamber. PMID:27403069

  9. Complication rate of molar crowns: a practice-based clinical evaluation.

    PubMed

    Rinke, S; Schäfer, S; Roediger, M

    2011-01-01

    This practice-based study evaluates the initial clinical performance of conventionally luted metal-ceramic and zirconia molar crowns fabricated with a prolonged cooling period of the veneering porcelain. Forty-nine patients were treated (group A: high precious alloy + low fusing porcelain; group B: zirconia crowns). All zirconia crowns were veneered with a modified porcelain firing cycle including a 6-minute cooling period. Ninety-two restorations (74 vital abutments/18 nonvital abutments) were evaluated after a mean observation period of 18.2 +/- 4.6 months. No complete failures or loss of vitality were recorded in either group. Two events were recorded in group A (1 loss of retention/1 minor ceramic chipping < 2 mm2). The third event occurred in group B (minor ceramic chipping <2 mm2). All ceramic defects could be polished intraorally. Statistical analysis revealed non-significant differences in success rates (p = 0.91) of metal-ceramic and zirconia crowns fabricated with a modified porcelain firing. The modified firing of the zirconia porcelain seems to decrease the risk for early ceramic chipping in the molar area, leading to a technical complication rate comparable to that of metal-ceramic crowns. PMID:22141230

  10. Patterns and rates of enamel growth in the molar teeth of early hominids.

    PubMed

    Beynon, A D; Wood, B A

    A recent study of the surface manifestation of incremental lines associated with enamel formation suggested that the crowns of early hominid incisor teeth were formed more rapidly than those of modern humans. In the absence of comparative data, the authors were forced to assume that enamel increments in fossil teeth were similar to those in modern humans. We have used evidence from the fractured surfaces of molar teeth to deduce estimates for both long- and short-period incremental growth markers within enamel in east African 'robust' australopithecine and early Homo teeth. We conclude that in these early hominids, crown formation times in posterior teeth, particularly in the large thick enamelled molar teeth of the east African 'robust' australopithecines, were shorter than those of modern humans. This evidence, considered together with data on crown and root formation times in modern apes, suggests that the posterior teeth in these hominids both formed and erupted more rapidly than those of modern man. These results have implications for attempts to assess dental and skeletal maturity in hominids. PMID:3104794

  11. Risk factors in the occurrence of molar-incisor hypomineralization amongst a group of Iraqi children.

    PubMed

    Ghanim, Aghareed; Manton, David; Bailey, Denise; Mariño, Rodrigo; Morgan, Michael

    2013-05-01

    BACKGROUND.  Despite the worldwide increasing interest in the prevalence studies of molar-incisor hypomineralization (MIH), there is still insufficient evidence to verify the aetiological factors of this condition. AIMS.  To investigate risk factors involved in the development of MIH in a group of school-aged Iraqi children. DESIGN.  Seven- to nine-year-old school children (823 of 1000 eligible, response rate of 82.3%) had their first permanent molars and incisors evaluated using the European Academy of Paediatric Dentistry evaluation criteria for MIH. Mothers completed a medical history questionnaire-based interview performed in the schools by a trained examiner. RESULTS.  For children with MIH, 6% reported no relevant medical history; the remaining 94% reported various medical conditions putatively associated with MIH compared with 70% for the non-affected group. Post-natal medical conditions (33.3%) were most frequently reported. When data were split into the possible risk effect groups, maternal psychological stress (OR, 3.24), frequent exposure to ultrasonic scans during the last gestational trimester (OR, 2.51) and birth order as a fourth sibling or later (OR, 3.17 and 5.73, respectively) were previously unreported significant risk factors and postulated as contributing to, or causing the defect. CONCLUSIONS.  Children with MIH had experienced a greater number of medical conditions than their unaffected peers with no single health event identified as a risk factor. PMID:22646757

  12. The maxillary molar endodontic access opening: A microscope-based approach.

    PubMed

    Mamoun, John Sami

    2016-01-01

    This article reviews the basic clinical techniques of performing a maxillary molar endodontic access opening, starting from the initial access opening into the pulp chamber, to the point where a size #10 file has been advanced to the apices of all three or four (or more) canals. The article explains how the use of the dental surgical operating microscope or microscope-level loupes magnification of ×6-8 or greater, combined with head-mounted or coaxial illumination, improve the ability of a dentist to identify microscopic root canal orifices, which facilitates the efficient creation of conservative access openings with adequate straight-line access in maxillary molars. Magnified photos illustrate various microscopic anatomical structures or landmarks of the initial access opening. Techniques are explored for implementing an access opening for teeth with vital versus necrotic pulpal tissues. The article also explores the use of piezoelectric or ultrasonic instruments for revealing root canal orifices and for removing pulp stones or calcified pulpal tissue inside the pulp chamber. PMID:27403069

  13. Randomized Controlled Trial to Evaluate the Efficacy of Oral Dexamethasone and Intramuscular Dexamethasone in Mandibular Third Molar Surgeries

    PubMed Central

    Kenjale, Prachi; Mony, Deepthi; Khatri, Isha; Kumar, Pratiksha

    2015-01-01

    Introduction Surgical removal of impacted third molar is the most commonly performed dento-alveolar procedure and is associated with post-operative pain, swelling and trismus. Aim The aim of the study was to compare the efficacy of dexamethasone administered orally with that of dexamethasone administered as an intra-masseteric injection in surgical removal of mandibular third molars. Materials and Methods Sixty patients with impacted mandibular third molars were selected to undergo surgical removal of mandibular third molars. They were divided into three groups of twenty each, viz., Control Group, Group taking Oral dexamethasone and Group taking Intra-masseteric dexamethasone. Evaluation was done over a period of seven days postoperatively to study the effects of the drug in terms of swelling, trismus and pain. Results ANOVA test was done and comparisons were made. It was found that there was a statistically significant difference with respect to the group taking oral dexamethasone in terms of resolution of trismus. It was also found that there was no statistical significance with respect to reduction in swelling in either of the groups. Conclusion Thus, it can be concluded that the oral route is superior compared to the intramuscular route when administering dexamethasone in surgical removal of mandibular third molars, with respect to drug dosage, bio-availability and resolution of trismus. PMID:26675081

  14. Anaesthesia Techniques for Maxillary Molars – A Questionnaire-Based Retrospective Field Survey of Dentist in Western India

    PubMed Central

    Mittal, Priya

    2016-01-01

    Introduction Clinicians use various anaesthesia techniques like Posterior Superior Alveolar (PSA) nerve block, buccal infiltration with or without supplemental anaesthesia like palatal and intraligamentary infiltrations for root canal treatment in maxillary molars. However there is no general consensus regarding which technique is enough for performing endodontic treatment in maxillary molars. Aim The aim of this questionnaire-based survey is to compare and evaluate the various techniques used to anaesthetize the maxillary molars and its effect on postoperative pain. Materials and Methods The data were obtained from 290 dental practitioners using a specially prepared questionnaire survey conducted anonymously. The questionnaire contained questions covering data such as years in dentistry, acquired specialty, techniques used for anaesthetizing maxillary molars, success of anaesthesia, and postoperative pain, etc. Results Buccal infilteration with supplemental anaesthesia in the form of palatal (82%) and intra-ligamentary infilteration (88%) show higher success rate compared to only buccal infilteration (69%). However, intra-ligamentary infilteration group showed highest rate (75%) of postoperative pain. General practitioners (62% of clinicians) prefer to give both buccal and palatal infilterations and specialists opt for only buccal infilteration (66-74% of specialists). Conclusion Only buccal infilteration is sufficient during root canal treatment of maxillary molars. Routine use of supplemental anaesthesia in the form of palatal and intra-ligamentary infilteration is not necessary unless patient experiences discomfort during endodontic treatment. However, intra-ligamentary infilteration may lead to postoperative discomfort in the form of pain. PMID:27134993

  15. Selenium:mercury molar ratios in freshwater fish from Tennessee: individual, species, and geographical variations have implications for management.

    PubMed

    Burger, Joanna; Gochfeld, Michael; Jeitner, C; Donio, M; Pittfield, T

    2012-06-01

    Vertebrates, including humans, can experience adverse effects from mercury consumed in fish. Humans often prefer large predatory fish that bioaccumulate high mercury levels. Recent attention has focused on the role of selenium countering mercury toxicity, but there is little research on the selenium:mercury molar ratios in freshwater fish. We examine selenium:mercury molar ratios in freshwater fish from Tennessee at Poplar Creek which receives ongoing inputs of mercury from the Department of Energy's Oak Ridge Y-12 facility. Our objective was to determine variation of the ratios within species that might affect the protectiveness of selenium against mercury toxicity. Within species, the ratio was correlated significantly and positively with fish length only for two species. There was great individual variation in the selenium:mercury molar ratio within each species, except striped bass. The lack of a clear relationship between the selenium:mercury molar ratio and fish length, and the intraspecific variation, suggests that it would be difficult to use the molar ratio in predicting either the risk from mercury toxicity or in devising consumption advisories. PMID:22456727

  16. Selenium:Mercury Molar Ratios in Freshwater Fish from Tennessee: Individual, Species, and Geographical Variations have Implications for Management

    PubMed Central

    Burger, Joanna; Gochfeld, Michael; Jeitner, C.; Donio, M.; Pittfield, T.

    2014-01-01

    Vertebrates, including humans, can experience adverse effects from mercury consumed in fish. Humans often prefer large predatory fish that bioaccumulate high mercury levels. Recent attention has focused on the role of selenium countering mercury toxicity, but there is little research on the selenium:mercury molar ratios in freshwater fish. We examine selenium:mercury molar ratios in freshwater fish from Tennessee at Poplar Creek which receives ongoing inputs of mercury from the Department of Energy’s Oak Ridge Y-12 facility. Our objective was to determine variation of the ratios within species that might affect the protectiveness of selenium against mercury toxicity. Within species, the ratio was correlated significantly and positively with fish length only for two species. There was great individual variation in the selenium:mercury molar ratio within each species, except striped bass. The lack of a clear relationship between the selenium:mercury molar ratio and fish length, and the intraspecific variation, suggests that it would be difficult to use the molar ratio in predicting either the risk from mercury toxicity or in devising consumption advisories. PMID:22456727

  17. Approach for determination of ATP:ADP molar ratio in mixed solution by surface-enhanced Raman scattering.

    PubMed

    Fang, Hui; Yin, Hong Jun; Lv, Ming Yang; Xu, Hai Jun; Zhao, Yong Mei; Zhang, Xin; Wu, Zheng Long; Liu, Luo; Tan, Tian Wei

    2015-07-15

    The ATP:ADP molar ratio is an important physiological factor. However, in previous literatures, ATP and ADP could not be distinguished by Raman spectroscopy due to the high similarity of molecular structure. To challenge this problem, also considering that the γ phosphate group may interact with adenine group and cause a different variation of the Raman spectrum than that of ADP, a highly sensitive, low-cost, environment protecting, flexible and super-hydrophobic Au nanoparticles/cicada wing (Au/CW) substrate with three-dimension structure was fabricated and employed as an active surface-enhanced Raman scattering (SERS) substrate to detect the ATP:ADP molar ratios. The concentration as low as 10(-8)M for ATP and ADP was analyzed to determine the limit of detection. This SERS study on various ATP:ADP molar ratios demonstrates that ATP:ADP could be distinguished and the quantitative determination of ATP content was achieved. Moreover, a principle was speculated based on the molecular structures of ATP and ADP of the Raman peaks centered at ~685 and ~731cm(-1) to explain the linear relationship between the area ratio and the molar ratio. A new method has been developed for quantitative determination of ATP:ADP molar ratio based on Au/CW substrate by the SERS method. PMID:25703730

  18. Extremely Rare Form of Impaction Bilateral Kissing Molars: Report of a Case and Review of the Literature

    PubMed Central

    Bayar, Gurkan Rasit; Altug, Hasan Ayberk; Kiran, Serkan

    2016-01-01

    Kissing molars (KM) or rosette formation is a term that is used to describe impacted teeth contacting occlusal surfaces in a single follicular space and their roots pointing in opposite directions. In some cases kissing molars can be seen but occurrence of bilateral kissing molars is extremely rare phenomenon in the dental literature and the aetiology of this phenomenon is still unknown. In this paper we describe a case and review of the literature and discuss the management of this pathology. In our case, extremely rare form of impacted bilateral kissing molars was extracted surgically. The decision of extraction of asymptomatic kissing molars represents surgical dilemma. There may be many surgical complications; on the other hand in some cases surgical intervention is unavoidable. Few treatment options were described in the literature. This phenomenon can be sign of various medical conditions that may require further investigation. In this paper, our treatment option is in agreement with the literature suggesting the surgical removal of both teeth at either side of the mandible. PMID:27403349

  19. Partial molar volumes and viscous properties of glycine-aqueous urea solutions at 298.15 K

    NASA Astrophysics Data System (ADS)

    Deosarkar, S. D.; Ban, A. R.; Tawde, P. D.; Sawale, R. T.

    2015-07-01

    Density (ρ) and viscosity (η) of glycine ( c = 0.02-0.22 mol dm-3) in aqueous urea ( c = 0.5, 1.5, and 3.0 mol dm-3) solutions were measured at 298.15 K. Experimental density data has been used to calculate apparent molar volumes (φv) of glycine in aqueous and aqueous-urea solutions at 298.15 K. The dependence of apparent molar volumes on concentration of glycine was fitted to the Massons relation and apparent molar volume of glycine at infinite dilution (partial molar volume, φ{v/0}) was determined graphically. The partial molar volumes of transfer (Δtrφ{v/0}) of glycine at infinite dilution from pure water to aqueous-urea solutions at 298.15 K were calculated and interpreted in terms of various interactions and structural fittings in studied solutions. The relative viscosity data has been analyzed by Jones-Dole relation and viscosity B-coefficients were determined graphically. Viscosity B-coefficient of transfer (Δ B) was also calculated and compared with Δtrφ{v/0}.

  20. Pulp/tooth ratio of mandibular first and second molars on panoramic radiographs: An aid for forensic age estimation

    PubMed Central

    Shah, Palak H.; Venkatesh, Rashmi

    2016-01-01

    Objective: To determine and compare the accuracy of pulp/tooth ratio method in mandibular first and second molar teeth in forensic age estimation. Materials and Methods: A total 300 panoramic radiographs of the Gujarati population (187 males and 113 females) were studied. The measurements of Pulp Chamber Height (PCH) and Crown Root Trunk Height (CRTH) were performed on the mandibular first and second molar teeth. The acquired data was subjected to correlation and regression. Results: The pulp chamber crown root trunk height ratios (PCTHR) of both the first (r = −0.609) and second molars (r = −0.422) were significantly correlated with the age of the individual. Individual regression formulae were derived for both the teeth which were then used separately to calculate the age. The standard errors estimate (SEE) for the first and second molars were 8.84 years and 10.11 years, respectively. There was no statistically significant difference between chronological and calculated age by both the teeth (P = 1.000). Conclusion: The mandibular first and second molar is a potential tool for age estimation in forensic dentistry. The pulp/tooth ratio of both the teeth is a useful method for forensic age prediction with reasonable accuracy in the Gujarati population.

  1. Radicular anatomy of permanent mandibular second molars in an Iranian population: A preliminary study

    PubMed Central

    Akhlaghi, Nahid M.; Abbas, Fatemeh Mashadi; Mohammadi, Mostafa; Shamloo, Mohammad Reza Karami; Radmehr, Orkideh; Kaviani, Ramin; Rakhshan, Vahid

    2016-01-01

    Background: Root morphology is of utmost importance to endodontic sciences. Since there are a few studies on the morphology of mandibular second molars' roots, and some anatomical variables are not evaluated before, the aim of this study was to investigate thoroughly radicular anatomy of this tooth. Materials and Methods: This ex vivo study was performed on 150 intact mandibular second molars. After access cavity preparation and ensuring canal patency, Indian ink was injected into root canals from the orifices. The teeth became transparent using methyl salicylate storage. Then, they were inspected by an endodontist under a ×10 stereomicroscope regarding numerous root morphological variables. Data were analyzed using chi-square test and analysis of variance (α = 0.05). Results: About 86.7% of teeth had two roots and 13.3% were single-rooted (P = 0.0001), of which, 50% were C-shaped (6.7% of all teeth, P = 0.0001). 86.7% of mesial roots were double canalled, whereas 75.3% of distal roots were single canalled (P = 0.0001). 71.45% and 95.3% of the mesial and distal roots had one apical foramen, respectively (P = 0.0001). Apical foramens were mostly central followed by lingual in most cases. Distances between apical foramen and apical constriction ranged between 0.27 and 0.40 mm (P = 0.0545). Distances between apical foramen and root apices ranged between 0.30 and 0.47 mm (P = 0.0001). Vertucci classifications of mesial canals were Type II in 62.6% and Type IV in 37.4%. 86.2% of single-canal distal roots were Type I. 66.7% of double-canal distal roots were Type II and 33.3% were Type IV (P = 0.0001). The mean root lengths from cervical to apex of mesial, distal, and single roots were 14.02 ± 0.85 (95% confidence interval [CI] = 13.87–14.17), 13.35 ± 0.91 (95% CI = 13.19–13.50), and 14.25 ± 0.72 mm (95% CI = 13.91–14.58), respectively. The extents of canal curvatures varied between 20° and 31° buccolingually (P = 0.0000), and between 19° and 27

  2. Economic Modeling of Sealing Primary Molars Using a “Value of Information” Approach

    PubMed Central

    Ney, J.P.; van der Goes, D.N.; Chi, D.L.

    2014-01-01

    The objective was to evaluate 2 primary molar sealant strategies for publicly insured children using an “expected value of perfect information” (EVPI) approach. We converted a 10,000-observation tooth-level cost-effectiveness simulation model comparing 2 primary molar sealant strategies – always seal (AS) and standard care (SC) – with a 1,250-observation child-level model. Costs per child per restoration or extraction averted were estimated. Opportunity losses under the AS strategy were determined for children for whom SC was the optimal choice. We determined the EVPI by multiplying mean opportunity losses by the projected incident population of publicly insured 3-year-olds in the US over 10 years with costs discounted at 2%. All analyses were conducted under assumptions of high and low intrachild correlations between at-risk teeth. The AS strategy cost $43.68 over SC (95% CI: −$5.50, $92.86) per child per restoration or extraction averted under the high intrachild correlation assumption and $15.54 (95% CI $7.86, $23.20) under the low intrachild correlation. Under high intrachild correlation, mean opportunity losses were $80.28 (95% CI: $76.39, $84.17) per child, and AS was the optimal strategy in 31% of children. Under low correlation, mean opportunity losses were $14.61 (95% CI: $12.20, $17.68) and AS was the optimal strategy in 87% of children. The EVPI was calculated at $530,813,740 and $96,578,389 (for high and low intrachild correlation, respectively), for a projected total incident population of 8,059,712 children. On average, always sealing primary molars is more effective than standard care, but widespread implementation of this preventive approach among publicly insured children would result in large opportunity losses. Additional research is needed to identify the subgroups of publicly insured children who would benefit the most from this effective and potentially cost-saving public health intervention. PMID:25056993

  3. A comparison of the effects of methylprednisolone and tenoxicam on pain, edema, and trismus after impacted lower third molar extraction

    PubMed Central

    Ilhan, Ozgur; Agacayak, Kamil Serkan; Gulsun, Belgin; Koparal, Mahmut; Gunes, Nedim

    2014-01-01

    Background The aim of the present study was to compare the effects of preemptive intravenous tenoxicam and methylprednisolone administrations on extraction of impacted third molars. Material/Methods This was a placebo-controlled, randomized, double-blind, clinical trial. A total of 60 adult patients ages 18–40 years with the complaints of impacted third molar teeth were included in the study. Results The postoperative swelling ratios (p<0.05) and pain scores (p<0.05) were significantly better in both study groups than in the control group and there was no statistically significant difference between methylprednisolone and tenoxicam groups with regards to the edema and pain relief. Conclusions Preoperative administration of 80 mg methylprednisolone achieves better control of trismus than tenoxicam without any significant differences in edema and pain control in impacted third molar teeth extraction. PMID:24473372

  4. Endodontic Microsurgical Treatment of a Three-rooted Mandibular First Molar with Separate Distolingual Root: Report of One Case.

    PubMed

    Wang, Han Guo; Xu, Ning; Yu, Qing

    2016-01-01

    The separate distolingual (DL) roots of three-rooted mandibular first molars are thought to be too difficult for performing apical surgery. This article represents microsurgical treatment of a three-rooted mandibular first molar with a separate DL root. The procedure includes incision and flap retraction, osteotomy, apicoectomy, retropreparation and retrofilling of the root canal, using micro instruments, ultrasonic retrotips and mineral trioxide aggregate (MTA) under a dental operating microscope. Two mm in length of apical root resection, 2 mm in depth of root canal retropreparation with a personalised ultrasonic retrotip, and 2 mm in length of retrofilling with MTA are the key points for accomplishment of apical surgery on separate DL roots. The case was followed up for 15 months after surgery. Clinical and radiographic examinations revealed complete healing of periapical tissue. Separate DL roots of three-rooted mandibular first molars can be treated by endodontic microsurgery with modifications from standard protocol. PMID:27622221

  5. Mineral trioxide aggregate pulpotomy in autotransplanted immature mandibular third molar with a 4-year follow-up.

    PubMed

    Dharmani, Umesh; Jadhav, Ganesh Ranganath; Kaur Dharmani, Charan Kamal; Devi, Takhellambam Premlata

    2016-01-01

    Autotransplantation is the surgical transposition of a tooth from its original site to another, replacing a lost or a compromised tooth by another tooth, usually the third molar in the same individual. This technique is considered a viable method due to its high success rate, well-grounded treatment option, provided the case selection and the procedure followed is within the acceptable limits. Autotransplantation is considered as an alternative approach of oral rehabilitations in a conservative manner mainly in young patients with compromised financial conditions to perform a high cost treatment. It is a fast way to recover function and aesthetic properties without interfering with the orofacial growth. This report describes a successful 4-year follow-up of a case of immediately performed mineral trioxide aggregate (MTA) pulpotomy in autotransplantated mandibular left immature third molar to replace the mandibular left first molar that was extracted due to extensive carious lesion. PMID:27217648

  6. Is Pederson Index a True Predictive Difficulty Index for Impacted Mandibular Third Molar Surgery? A Meta-analysis.

    PubMed

    Bali, Amit; Bali, Deepika; Sharma, Ashutosh; Verma, Gaurav

    2013-09-01

    The aim of this meta-analysis was to find out the clinical reliability of Pederson index in assessing the difficulty of surgery for impacted mandibular 3rd molar. The relevant articles were selected by Hand search and electronic media (Medline, Pubmed, Embase Cochrane library, ISI web of science) from Jan 2000 to Dec 2010. All the relevant articles were properly screened and findings were extracted from the articles. Pederson index had shown low sensitivity and specificity in predicting the difficulty of surgery for impacted mandibular 3rd molar. Positive and negative likelihood ratio had also shown the unreliability of Pederson index. The meta-analysis of the current literature concluded that Pederson index is not a reliable test to predict the surgical difficulty of impacted mandibular 3rd molar. PMID:24431870

  7. Mineral trioxide aggregate pulpotomy in autotransplanted immature mandibular third molar with a 4-year follow-up

    PubMed Central

    Dharmani, Umesh; Jadhav, Ganesh Ranganath; Kaur Dharmani, Charan Kamal; Devi, Takhellambam Premlata

    2016-01-01

    Autotransplantation is the surgical transposition of a tooth from its original site to another, replacing a lost or a compromised tooth by another tooth, usually the third molar in the same individual. This technique is considered a viable method due to its high success rate, well-grounded treatment option, provided the case selection and the procedure followed is within the acceptable limits. Autotransplantation is considered as an alternative approach of oral rehabilitations in a conservative manner mainly in young patients with compromised financial conditions to perform a high cost treatment. It is a fast way to recover function and aesthetic properties without interfering with the orofacial growth. This report describes a successful 4-year follow-up of a case of immediately performed mineral trioxide aggregate (MTA) pulpotomy in autotransplantated mandibular left immature third molar to replace the mandibular left first molar that was extracted due to extensive carious lesion. PMID:27217648

  8. Influence of Ni/Co molar ratio on electromagnetic properties and microwave absorption performances for Ni/Co paraffin composites

    NASA Astrophysics Data System (ADS)

    Yan, S. J.; Dai, S. L.; Ding, H. Y.; Wang, Z. Y.; Liu, D. B.

    2014-05-01

    Ni and Co metallic microparticles with submicron size were synthesized with a simple wet chemical reduction method at a relatively low temperature. Then their morphologies and structures were characterized by SEM and XRD. Ni metallic microparticles have spherical-shape morphology with fcc crystalline structure, however, Co has a distinct leaf-like morphology with the fcc and hcp mixed phases crystalline structures. For the characterization of their electromagnetic properties, paraffin matrix composites containing different molar ratio Ni and Co mixture powder as fillers were prepared. It was found that both the electromagnetic properties and electromagnetic microwave absorption performances of absorber layer were remarkably influenced by Ni/Co molar ratio. The electromagnetic microwave absorption performances were significantly improved by blending Ni and Co metallic microparticles into paraffin matrix with changing Ni/Co molar ratio, and enhanced mechanism were discussed.

  9. Molar-mass measurement of a 28Si-enriched silicon crystal for determination of the Avogadro constant

    NASA Astrophysics Data System (ADS)

    Narukawa, Tomohiro; Hioki, Akiharu; Kuramoto, Naoki; Fujii, Kenichi

    2014-06-01

    The molar mass of a 28Si-enriched crystal was measured at the National Metrology Institute of Japan to determine the Avogadro constant by the x-ray crystal density method as part of the International Avogadro Coordination project. The molar mass was determined by isotope ratio measurements using a multicollector inductively coupled plasma mass spectrometer combined with an isotope dilution technique. The 28Si-enriched crystal was dissolved in tetramethylammonium hydroxide and three different blended solutions were used to correct for mass bias in the measurement. The molar mass of the 28Si-enriched crystal was determined to be 27.976 970 09 g mol-1 with a standard uncertainty of 0.000 000 14 g mol-1. This corresponds to a relative standard uncertainty of 5.2 × 10-9. This result is consistent with measurements reported by the Physikalisch-Technische Bundesanstalt, Germany.

  10. Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation

    SciTech Connect

    Schnell, Sondre K.; Skorpa, Ragnhild; Bedeaux, Dick; Kjelstrup, Signe; Vlugt, Thijs J. H.; Simon, Jean-Marc

    2014-10-14

    We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtained with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation.

  11. Demineralization of enamel in primary second molars related to properties of the enamel.

    PubMed

    Sabel, N; Robertson, A; Nietzsche, S; Norén, J G

    2012-01-01

    Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel. Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher. PMID:22629152

  12. Immunohistochemical demonstration of exocytosis-regulating proteins within rat molar dentinal tubules.

    PubMed

    Norlin, T; Hilliges, M; Brodin, L

    1999-03-01

    No morphologically defined synaptic structures have so far been detected between nerve terminals and the dentine-producing odontoblasts. Recent studies of the molecular mechanisms in neuronal exocytosis have identified several proteins that participate in synaptic-vesicle exocytosis. By localizing these proteins with immunohistochemical methods, information about the capacity for synaptic exocytosis should be obtained. Here, antibodies directed against some of the exocytosis-related proteins were used to investigate whether they are present in nerve fibers within the dentinal tubules in rat molars. Antibodies against synaptosome-associated protein of 25 kDa, Rab 3, synaptotagmin and synapsin all produced a punctuate staining pattern, suggesting that the proteins are accumulated in bouton-like elements. The results demonstrate that a set of exocytosis-related proteins is accumulated in the dentinal tubules, most probably within the intradentinal nerves. This finding is consistent with the hypothesis that intradentinal nerves can mediate efferent signals. PMID:10217513

  13. Infected Dentigerous Cyst of Maxillary Sinus Arising from an Ectopic Third Molar

    PubMed Central

    Guruprasad, Yadavalli; Chauhan, Dinesh Singh; Kura, Umashankar

    2013-01-01

    A dentigerous cyst or follicular cyst is a form of odontogenic cyst. It is believed that it forms during the development of the tooth and is associated with pressure exerted by the crown of an unerupted (or partially erupted) tooth on the fluid within the follicular space. Typically, dentigerous cysts are painless and discovered during routine radiographic examination. However, they may be large and result in a palpable mass. Additionally, as they grow they displace adjacent teeth. They almost exclusively occur in permanent dentition. The cyst is lined by stratified squamous non-keratinizing epithelium. About 70% of dentigerous cysts occur in the mandible and 30% in the maxilla. Dentigerous cysts associated with ectopic teeth within the maxillary sinus are very rare. We report radiologic and pathologic features in a rare case of infected dentigerous cyst of maxillary sinus arising from an ectopic third molar in a 21-year-old female patient. PMID:24516770

  14. Removal of impacted third molars by oral/maxillofacial surgery and general dentistry residents.

    PubMed

    Handelman, S L; Black, P M; Desjardins, P; Gatlin, L; Simmons, L

    1993-01-01

    The post-operative symptoms of patients who had undergone third molar extractions by Oral/Maxillofacial Surgery (OMS) residents were compared with those of patients whose extractions were performed by General Dentistry (GD) residents. The OMS group had more extractions per visit and were more likely to use intravenous sedation than the GD-treated group. No significant differences were found when the provider groups were compared by post-operative symptoms such as osteitis, infection, trismus, or paresthesia/dysthesia. The pain relief due to postoperative analgesics during the immediate 12-hour period was higher for patients treated by GD residents. Multiple regression analysis revealed that this difference was due to the number of teeth extracted and the complexity of the surgical procedure, independent of type of provider. PMID:8153854

  15. Viable Intrauterine Pregnancy and Coexisting Molar Pregnancy in a Bicornuate Uterus: A Rare Presentation

    PubMed Central

    Krishnamoorthy, Kavitha; Gerkowicz, Sabrina; Verma, Usha

    2016-01-01

    A complete hydatidiform mole with a viable coexisting fetus (CMCF) is a rare occurrence. Similarly, Mullerian anomalies such as a bicornuate uterus are uncommon variants of normal anatomy. We report a case of a 40-year-old female with a known bicornuate uterus presenting at 13 weeks gestation with vaginal bleeding. Ultrasound findings showed a healthy viable pregnancy in the right horn with complete molar pregnancy in the left horn. After extensive counseling, the patient desired conservative management, however, was unable to continue due to profuse vaginal bleeding. The patient underwent suction dilation and curettage under general anesthesia and evacuation of the uterine horns. Postoperatively, the patient was followed until serum beta-human chorionic gonadotropin (β-hCG) level dropped to <5 mU. This is the first case of a CMCF reported in a bicornuate uterus, diagnosed with the use of ultrasound imaging. PMID:27403404

  16. Cone Beam Computed Tomographic Evaluation and Diagnosis of Mandibular First Molar with 6 Canals

    PubMed Central

    Pasha, Shiraz; Chaitanya, Bathula Vimala; Somisetty, Kusum Valli

    2016-01-01

    Root canal treatment of tooth with aberrant root canal morphology is very challenging. So thorough knowledge of both the external and internal anatomy of teeth is an important aspect of root canal treatment. With the advancement in technology it is imperative to use modern diagnostic tools such as magnification devices, CBCT, microscopes, and RVG to confirm the presence of these aberrant configurations. However, in everyday endodontic practice, clinicians have to treat teeth with atypical configurations for root canal treatment to be successful. This case report presents the management of a mandibular first molar with six root canals, four in mesial and two in distal root, and also emphasizes the use and importance of Cone Beam Computed Tomography (CBCT) as a diagnostic tool in endodontics. PMID:26904310

  17. Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Schnell, Sondre K.; Skorpa, Ragnhild; Bedeaux, Dick; Kjelstrup, Signe; Vlugt, Thijs J. H.; Simon, Jean-Marc

    2014-10-01

    We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtained with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation.

  18. Molar microwear of subfossil lemurs: improving the resolution of dietary inferences.

    PubMed

    Rafferty, K L; Teaford, M F; Jungers, W L

    2002-11-01

    In this study we use molar microwear analyses to examine the trophic distinctions among various taxa of Malagasy subfossil lemurs. High resolution casts of the teeth of Megaladapis, Archaeolemur, Palaeopropithecus, Babakotia, and Hadropithecus were examined under a scanning electron microscope. Megaladapis was undoubtedly a browsing folivore, but there are significant differences between species of this genus. However, dietary specialists appear to be the exception; for example, Palaeopropithecus and Babakotia probably supplemented their leaf-eating with substantial amounts of seed-predation, much like modern indrids. Hadropithecus was decidedly not like the modern gelada baboon, but probably did feed on hard objects. Evidence from microwear and coprolites suggests that Archaeolemur probably had an eclectic diet that differed regionally and perhaps seasonally. Substantial trophic diversity within Madgascar's primate community was diminished by the late Quaternary extinctions of the large-bodied species (>9 kg). PMID:12457853

  19. Endodontic management of permanent mandibular molars with 6 root canals: report of 3 cases.

    PubMed

    Malhotra, Amit; Ahlawat, Jyoti; Bansal, Chirag; Tahiliani, Divya

    2016-01-01

    Aberrations in the internal dental anatomy present challenges for clinicians performing endodontic therapy. These challenges have been partly resolved in recent years by a more comprehensive knowledge of root canal anatomy as well as advancements in the endodontic armamentarium. The aim of this case series is to describe successful root canal treatment, under magnification, in 3 cases of mandibular first molars with 6 root canals. Two of these teeth had 2 roots (mesial and distal) with 3 canals in each root; the third tooth had 3 root canals located mesially and 3 present distally as well as a radix entomolaris. A distal root with 3 canals is rare; however, it is important to look for such anatomical variations to ensure successful endodontic therapy. PMID:27599288

  20. Facial Pain Associated with CPAP Use: Intra-Sinusal Third Molar

    PubMed Central

    Mermod, Maxime; Broome, Martin; Hoarau, Remy; Zweifel, Daniel

    2014-01-01

    Objective. This paper describes a patient with left hemifacial pain elicited by the use of a CPAP mask. Case Report. A 74-year-old man was referred with a history of pain in the left maxillary sinus related to the use of his CPAP interface, thereby prohibiting the use of the latter. Computed tomography revealed an intra-sinusal ectopic third molar in the left maxillary sinus floor corresponding to the painful area. After removal of the ectopic tooth under local anesthesia by a Caldwell-Luc approach, the patient was relieved of his symptoms. Conclusion. Although an ectopic tooth in the maxillary sinus is rare, this case points out the importance of actively looking for a regional problem if patients cannot tolerate the CPAP interface since this can lead to issues of incompliance and medical complications due to the untreated obstructive sleep apnoea syndrome. PMID:25002982