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1

Patient satisfaction with single-tooth implant therapy in the esthetic zone.  

PubMed

This prospective study assessed patient satisfaction before and after single-tooth implant therapy in the esthetic zone. Before implant therapy, patients wore an acrylic resin tissue-supported removable partial denture (RPD). A total of 153 patients were included. Self-administered questionnaires regarding function, comfort, and esthetics were used to measure patient satisfaction with the RPD and with the implant at 6 and 18 months post-implant placement. Overall satisfaction was explored with a visual analog scale. It was suggested that patient satisfaction with a single-tooth implant in the esthetic zone is high and it improved when compared with an RPD that patients wore before implant treatment. PMID:24905262

Hartog, Laurens; Meijer, Henny J A; Santing, Hendrick J; Vissink, Arjan; Raghoebar, Gerry M

2014-01-01

2

Immediate loading of single-tooth implants in the anterior maxilla. Preliminary results after one year.  

PubMed

According to the standard protocol, a load-free healing period is one of the most emphasized requirements for implant integration. Recent studies have encouraged a progressive shortening of the healing period for single-tooth implants and immediate loading has been proposed for the aesthetic zone in the maxilla. The present study evaluated clinical outcomes of immediately loaded FRIALIT-2 Synchro implants 12 months after placement in the maxillary incisal region. In the course of our investigation, nine patients have been treated following an immediate loading protocol. The stepped-screw type implants were inserted with an increasing torque up to 45 Ncm, thus measuring the primary stability of the implants. All implants were immediately restored with unsplinted acrylic resin provisional crowns and the patients provided with occlusal splints. Regular controls were performed at monthly intervals, intraoral radiographs were taken directly after implant placement, 6 and 12 months post insertion. The survival rate, clinical stability (Periotest) and radiographic coronal bone defects (CBD) were evaluated at delivery of the definitive superstructures (CBD 6) and 6 months later (CBD 12). Twelve FRIALIT-2 Synchro stepped screws of 3.8, 4.5 and 5.5 mm diameter and 13 and 15 mm length were placed in the incisal maxillary region. The median Periotest value 6 months post insertion was -2 with a minimum of -5 and a maximum of +2. The mean coronal bone level changes (CBD) at 6 and 12 months were 0.45 and 0.75 mm. No implant failed up to 12 months after insertion, resulting in a 100% survival rate. The presented results showed promising data for immediately loaded single-tooth implants in the anterior maxilla. Periotest values were within the range published for submerged implants. The radiographic coronal bone resorption after 6 and 12 months was even less than evaluated for implants placed in a standard two-stage procedure. It is evident that successful immediate loading protocols require a careful and strict patient selection aimed at achieving the best primary stability and avoiding any excessive functional or non-functional loading. Additional research needs to be done to provide data in situations where problems of poor bone quality, multiple implants or augmentation procedures must be overcome. PMID:12656877

Lorenzoni, Martin; Pertl, Christof; Zhang, Kehao; Wimmer, Gernot; Wegscheider, Walther A

2003-04-01

3

Are predoctoral students able to provide single tooth implant restorations in the maxillary esthetic zone?  

PubMed

The objective of this study was to assess the ability of the University of Illinois at Chicago College of Dentistry (UIC-COD) predoctoral students to provide single tooth implant (STI) prostheses in the maxillary esthetic zone. The patient's esthetic satisfaction and the correlation between prosthodontists' and patients' perspectives were examined. Twenty-seven patients were recruited for recall examinations at the UIC-COD predoctoral implant program and underwent clinical and radiographic examination with clinical photographs of the implant sites. The patients completed a semantic differential scale questionnaire. The collected information was formulated into a PowerPoint presentation for two Diplomate of the American Board of Prosthodontists to use the Pink/White Esthetic Score (PES/WES) to evaluate the esthetic outcome. Descriptive analyses, Cohen kappa test, and Spearman rank correlation coefficient test were performed. The average PES/WES were above 6.0 (out of 10). The median for the patient satisfaction and esthetic outcome questionnaires were 10 and 9, respectively, on a scale with 10=highest. There was a medium and positive correlation between prosthodontists' and patients' perspectives in esthetic outcome. This study found that, with strict guidance and proper selection criteria, predoctoral students were able to provide esthetically acceptable STI prostheses in the maxillary esthetic zone and patients were satisfied with the treatment provided. PMID:24789838

Taylor, Emily J; Yuan, Judy Chia-Chun; Lee, Damian J; Harlow, Rand; Afshari, Fatemeh S; Knoernschild, Kent L; Campbell, Stephen D; Sukotjo, Cortino

2014-05-01

4

Treatment of a Class II Division 2 malocclusion with space reopening for a single-tooth implant  

Microsoft Academic Search

This case report describes the treatment of an adolescent girl with a skeletal Class II Division 2 malocclusion and impinging overbite. One of 2 previously extracted premolars had to be replaced by a single-tooth implant after adequate space reopening. An optimal overbite-overjet relationship was achieved through significant intrusion and proclination of maxillary and mandibular incisors. A horizontally impacted mandibular second

Roy Sabri

2001-01-01

5

Single-Tooth Morse Taper Connection Implant Placed in Grafted Site of the Anterior Maxilla: Clinical and Radiographic Evaluation  

PubMed Central

The aim of this study was to achieve aesthetically pleasing soft tissue contours in a severely compromised tooth in the anterior region of the maxilla. For a right-maxillary central incisor with localized advanced chronic periodontitis a tooth extraction followed by reconstructive procedures and delayed implant placement was proposed and accepted by the patient. Guided bone regeneration (GBR) technique was employed, with a biphasic calcium-phosphate (BCP) block graft placed in the extraction socket in conjunction with granules of the same material and a resorbable barrier membrane. After 6 months of healing, an implant was installed. The acrylic provisional restoration remained in situ for 3 months and then was substituted with the definitive crown. This ridge reconstruction technique enabled preserving both hard and soft tissues and counteracting vertical and horizontal bone resorption after tooth extraction and allowed for an ideal three-dimensional implant placement. Localized severe alveolar bone resorption of the anterior maxilla associated with chronic periodontal disease can be successfully treated by means of ridge reconstruction with GBR and delayed implant insertion; the placement of an early-loaded, Morse taper connection implant in the grafted site was effective to create an excellent clinical aesthetic result and to maintain it along time.

Mangano, Francesco Guido; Zecca, Piero; Luongo, Fabrizia; Iezzi, Giovanna; Mangano, Carlo

2014-01-01

6

Alumina-zirconia machinable abutments for implant-supported single-tooth anterior crowns.  

PubMed

Innovative materials and application techniques are constantly being developed in the ongoing search for improved restorations. This article describes a new material and the fabrication process of aesthetic machinable ceramic anterior implant abutments. The ceramic material utilized is a mixture of alumina (aluminum oxide) and ceria (cerium oxide) with partially stabilized zirconia (zirconium oxide). The initial core material is a cylinder with a 9-mm diameter and a 15-mm height, obtained by ceramic injection and presintering processes. The resultant alumina-zirconia core is porous and readily machinable. It is secured to the analog, and its design is customized by machining the abutment to suit the particular clinical circumstances. The machining is followed by glass infiltration, and the crown is finalized. The learning objective of this article is to gain a basic knowledge of the fabrication and clinical application of the custom machinable abutments. PMID:9573856

Sadoun, M; Perelmuter, S

1997-01-01

7

Single-Tooth Implants  

MedlinePLUS

... upper or lower jawbone. Gold custom abutment The abutment can be made of titanium, gold or porcelain. ... The crown is screwed or cemented onto the abutment. If the crown is screwed to the abutment, ...

8

A 5-year comparison of marginal bone level following immediate loading of single-tooth implants placed in healed alveolar ridges and extraction sockets in the maxilla  

PubMed Central

Purpose: The aim of present investigation was to evaluate marginal bone level after 5-year follow-up of implants placed in healed ridges and fresh extraction sockets in maxilla with immediate loading protocol. Materials and Methods: Thirty-six patients in need of a single-tooth replacement in the anterior maxilla received 42 Astra Tech implants (Astra Tech Implant system™, Dentsply Implants, Mölndal, Sweden). Implants were placed either in healed ridges (group I) or immediately into fresh extraction sockets (group II). Implants were restored and placed into functional loading immediately by using a prefabricated abutment. Marginal bone level relative to the implant reference point was recorded at implant placement, crown cementation, 12, 36, and 60 months following loading using intra-oral radiographs. Measurements were made on the mesial and distal sides of each implant. Results: Overall, two implants were lost from the group II, before final crown cementation: they were excluded from the study. The mean change in marginal bone loss (MBL) after implant placement was 0.26 ± 0.161 mm for 1 year, and 0.26 ± 0.171 mm for 3 years, and 0.21 ± 0.185 mm for 5 years in extraction sockets and was 0.26 ± 0.176 mm for 1 year and 0.21 ± 0.175 mm for 3 years, and 0.19 ± 0.172 mm for 5 years in healed ridges group. Significant reduction of marginal bone was more pronounced in implants inserted in healed ridges (P < 0.041) compared to fresh surgical extraction sockets (P < 0.540). Significant MBL was observed on the mesial side of the implant after cementation of the provisional (P < 0.007) and after 12 months (P < 0.034) compared to the distal side which remained stable for 3 and 5 years observation period. Conclusions: Within the limitations of this study, responses of local bone to immediately loaded implants placed either in extraction sockets or healed ridges were similar. Functional loading technique by using prefabricated abutment placed during the surgery time seems to maintain marginal bone around implant in both healed and fresh extraction sites. PMID:24550840

Berberi, Antoine N.; Sabbagh, Joseph M.; Aboushelib, Moustafa N.; Noujeim, Ziad F.; Salameh, Ziad A.

2014-01-01

9

Use of titanium mesh in implant site development for restorative-driven implant placement: case report. Part 2: surgical protocol for single-tooth esthetic zone sites.  

PubMed

There are many techniques in the dental implant literature to augment bone for implant site development. The use of rigid titanium mesh was first described by Boyne in the mid-1980s to maintain regenerative space and to aid in unimpeded bone healing. Ti-mesh was used in this case report to demonstrate the predictability of this technique in creating bone augmentation in both a lateral and vertical direction prior to the placement of a single implant in site No. 5. The article describes the surgical steps for the use of ti-mesh in a single esthetic zone site with a 3-year follow-up. PMID:24841037

Levine, Robert A; Manji, Aleem; Faucher, Joanie; Fava, Philip

2014-05-01

10

Use of titanium mesh in implant site development for restorative-driven implant placement: case report. Part 1--Restorative protocol for single-tooth esthetic zone sites.  

PubMed

Predictably augmenting alveolar bone is a significant challenge in implant site development. A restorative-driven approach to implant placement aids in achieving esthetic harmony in the final restoration. This case report demonstrates techniques for treating patients with significant bony defects using a titanium mesh scaffold along with prosthetic steps in molding and conditioning soft tissues with the provisional restoration and the fabrication of a custom impression coping. This case is part of a larger consecutive case series of 77 titanium mesh units in 62 patients treated in a private periodontal practice setting and restored in private restorative practices, which will be published subsequently. In this titanium mesh case series, 14 other cases (a total of 15) were treated in a similar fashion as described in this case report in the category of "single implant placement in the maxillary anterior region." This case illustrates the primary advantages of the use of titanium mesh in such clinical situations. PMID:24773252

Levine, Robert A; Manji, Aleem; Faucher, Joanie; Present, Steven

2014-04-01

11

FEM evaluation of cemented-retained versus screw-retained dental implant single-tooth crown prosthesis  

PubMed Central

Prosthetic rehabilitation of partial or total edentulous patients is today a challenge for clinicians and dental practitioners. The application of dental implants in order to recover areas of missing teeth is going to be a predictable technique, however some important points about the implant angulation, the stress distribution over the bone tissue and prosthetic components should be well investigated for having final long term clinical results. Two different system of the prosthesis fixation are commonly used. The screw retained crown and the cemented retained one. All of the two restoration techniques give to the clinicians several advantages and some disadvantages. Aim of this work is to evaluate all the mechanical features of each system, through engineering systems of investigations like FEM and Von Mises analyses. The FEM is today a useful tool for the prediction of stress effect upon material and biomaterial under load or strengths. Specifically three different area has been evaluated through this study: the dental crown with the bone interface; the passant screw connection area; the occlusal surface of the two different type of crown. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed an adequate response for both type of prostheses, although cemented retained one showed better results over the occlusal area. PMID:24955150

Cicciu, Marco; Bramanti, Ennio; Matacena, Giada; Guglielmino, Eugenio; Risitano, Giacomo

2014-01-01

12

Finite Element Analysis of Biomechanical Interactions of A Tooth-Implant Splinting System for Various Bone Qualities  

Microsoft Academic Search

Background: The splinting of an implant and tooth is a rational alternative in some clinical situations. The complex biomechanical aspects of a tooth-implant system are derived from the dissimilar mobility between the osseointegrated implant and the tooth. The aim of this study was to analyze the biomechanics in a tooth-implant splinting system for various bone qualities with different occlusal forces

Chun-Li Lin; Shih-Hao Chang; Jen-Chyan Wang

13

Timing of implant placement relative to tooth extraction.  

PubMed

In recent years, immediate or early implant placement after tooth extraction has becoming more common. The present review focuses on the clinical outcome of immediate or early implant placement. Only limited knowledge exists about most of the factors with particular significance for this treatment mode. Randomized controlled clinical studies comparing the various treatment protocols are scarce. With the background in the existing literature some conclusions can be drawn with caution. Survival rates for implants placed immediately, early, delayed, or late seem to be similar in the short perspective and amounts to approximately 95%. Successful immediate implant placement may be possible in all regions of the jaws, although replacement of molars is more challenging. Chronic infection is not an absolute contraindication for immediate implant placement. It is controversial whether immediate placement of implants may preserve the alveolar bone. Small gaps between implant surface and socket wall have a potential for spontaneous healing. No consensus exists on the need for bone augmentation in these situations. With the limited information available it may be stated that a good prognosis can be obtained following immediate/early functional or non-functional loading of immediately placed implants. However, higher risk of failures seems to exist compared with a delayed, conventional approach. It is advocated that this treatment modality should be restricted to skilled well-trained teams. Data on the aesthetic outcomes following immediate/early implant placement are inconclusive, but this treatment can offer high patient satisfaction with the aesthetic and functional outcomes. PMID:18181932

Schropp, L; Isidor, F

2008-01-01

14

Long-term clinical effectiveness of oral implants in the treatment of partial edentulism. Seven-year life table analysis of a prospective study with ITI dental implants system used for single-tooth restorations.  

PubMed

One hundred and eight-seven ITI implants were prospectively followed from November 1992 to July 2000, in order to evaluate the clinical efficiency and the long-term prognosis in 109 partially edentulous patients (69 women and 40 men; average age 41.3 years). Of these 187 implants, 69.5% were placed in the mandible and 30.5% in the maxilla. After a healing period that ranged from three to six months, the osseointegrated implants (n = 184) were restored with single crowns. Three implants were extracted prior to loading the fixture and were considered early failures. Each implant was reassessed on a yearly basis, both clinically and radiographically. The results of the investigation, which were evaluated according to predefined success criteria, were reviewed in accordance with a life table method. During the follow-up, six cases were deemed to be late failures. In each of these cases, a suppurative infection of the peri-implant tissue was diagnosed: in one implant, the infection could not be eradicated and the implant was removed. When 11 drop-outs were included in the analysis, the cumulative survival and success rates for the whole sample group were 96.77% and 93.6%, respectively. When only prosthetically loaded implants were considered, the results increased to 99.35% for the cumulative survival rate and 96.18% for the cumulative success rate. The analysis on disaggregated data showed better results for maxillary restorations (survival rate 100%) in comparison to mandible restorations (survival rate 95.11%). It was concluded that, under standard anatomic conditions (bone site height > 8 mm, thickness > 6 mm), prosthetic restoration of partially edentulous patients with the ITI system can be described as a reliable and efficient therapy in the long term. PMID:11952733

Romeo, Eugenio; Chiapasco, M; Ghisolfi, M; Vogel, G

2002-04-01

15

Theoretical study of the effects of tooth and implant mobility differences on occlusal force transmission in tooth\\/implant-supported partial prostheses  

Microsoft Academic Search

Statement of problem. Despite their mobility differences under occlusal loads, a natural tooth and an implant are often used together to support fixed prostheses. In some situations, tooth\\/implant-supported partial prostheses include cantilever extensions, especially in the posterior region where the bone is inadequate for placement of an additional implant.Purpose. In this study, engineering beam theory was used to study the

Ramazan Kayacan; Roberto Ballarini; Robert L. Mullen

1997-01-01

16

Orthodontic single tooth intrusion with a removable interocclusal device: A clinical report.  

PubMed

Interdisciplinary therapy was used to treat a patient missing a single posterior tooth opposing an extruded tooth. The simple technique used a removable interocclusal device and elastic band for orthodontic intrusion over a 2-month period after implant placement in the opposing arch to aid in prosthetic site development. This approach was designed to increase the interocclusal space needed to restore the implant, obtain a more consistent occlusal plane, and improve esthetics. Clinical and radiographic examinations at the 6-month follow-up revealed an acceptable occlusal relationship and improved esthetic appearance that was achieved with the documented course of treatment. PMID:23684276

Slighly, Corey; Ramos, Van; Brousseau, Steve

2013-05-01

17

Immediate functional loading of single-tooth TiO2 grit-blasted implant restoration. A controlled prospective study in a porcine model. Part II: Histology and histomorphometry  

Microsoft Academic Search

BACKGROUND: Evidently, there is a fast-moving shift from delayed to immediate implant loading. The hypothesis to be tested was that bone reactions adjacent to single TiO2-microthreaded implants exposed to immediate masticatory loading for 10 weeks after placement would modulate osseointegration. MATERIALS AND METHODS: Cylindrical- and tapered-designed implants (Astra Tech AB, Molndal, Sweden) replaced first and third mandibular premolars respectively in

Vasilios A. Bousdras; Frank Walboomers; John A. Jansen; James L. Cunningham; Gordon Blunn; Aviva Petrie; Siegfried Jaecques; Ignace E. Naert; Steen Sindet-Pedersen; Allen E. Goodship

2007-01-01

18

Nanofibers implant functionalized by neural growth factor as a strategy to innervate a bioengineered tooth.  

PubMed

Current strategies for jaw reconstruction require multiple procedures, to repair the bone defect, to offer sufficient support, and to place the tooth implant. The entire procedure can be painful and time-consuming, and the desired functional repair can be achieved only when both steps are successful. The ability to engineer combined tooth and bone constructs, which would grow in a coordinated fashion with the surrounding tissues, could potentially improve the clinical outcomes and also reduce patient suffering. A unique nanofibrous and active implant for bone-tooth unit regeneration and also the innervation of this bioengineered tooth are demonstrated. A nanofibrous polycaprolactone membrane is functionalized with neural growth factor, along with dental germ, and tooth innervation follows. Such innervation allows complete functionality and tissue homeostasis of the tooth, such as dentinal sensitivity, odontoblast function, masticatory forces, and blood flow. PMID:24124118

Eap, Sandy; Bécavin, Thibault; Keller, Laetitia; Kökten, Tunay; Fioretti, Florence; Weickert, Jean-Luc; Deveaux, Etienne; Benkirane-Jessel, Nadia; Kuchler-Bopp, Sabine

2014-03-01

19

Dimensional profile of oral mucosa around combined tooth-implant-supported bridgework in macaque mandible  

Microsoft Academic Search

Purpose: A stable oral mucosa is crucial for long-term survival and biofunctionality of implants. Most of this evidence is derived from clinical and animal studies based solely on implant-supported prosthesis. Much less is known about the dimensions and relationships of this soft tissue complex investing tooth-implant-supported bridgework (TISB). The aim here was to obtain experimental evidence on the dimensional characteristics

C. H. Siar; C. G. Toh; T. B. T. Ali; D. Seiz; S. T. Ong

2012-01-01

20

Relationship of tooth mortality and implant treatment in Type 2 diabetes mellitus patients in Korean adults  

PubMed Central

PURPOSE The purpose of this study was to to analyze the effect of Type 2 diabetes on tooth mortality, implant treatment and prosthetic status. MATERIALS AND METHODS 275 Type 2 diabetics and 300 non-diabetics, aged 40-80 years were selected for analysis. The assessment of number of teeth, missing teeth, fixed prostheses (bridge pontics), implants using panoramic radiographs and dental records were carried out. RESULTS Diabetes mellitus (DM) patients had a higher number of missing teeth (P<.05) and placed implants (P=.074), age (P<.05), male gender percentage (P=.042), smoker percentage (P<.05) than non-DM patients. In univariate analysis, the patients in older group showed significantly higher number of tooth loss rate at the first dental examination than the patients in younger group. Tooth loss rate of smokers did not show higher value than that of non-smokers. When multiple variables including DM, age, smoking, gender were considered together, diabetics and older group patients showed significantly higher tooth loss rate at the first dental examination than non-diabetics and younger group patients, respectively. Smokers and male group did not show a significant difference than non-smokers and female group, respectively. CONCLUSION Tooth mortality and implant treatment rate were significantly higher in the DM group as indicated by univariate and multivariate logistic regression analysis. Old age groups showed significantly higher odds ratios and tooth loss rate. As diabetics showed the higher tooth loss rate than non-diabetics, diabetics also had more implant restorations than non-diabetics. PMID:23508020

Jung, Hyun-Yub; Kim, Yong-Gun; Jin, Myoung-Uk

2013-01-01

21

Correction of esthetic and biomechanical outcomes after maxillary anterior single dental implant fracture: a case report.  

PubMed

Rehabilitation of the single anterior tooth in the esthetic region after a dental implant fracture requires management of contributing biomechanical and/or biological etiologic factors. The multidisciplinary treatment of a fractured maxillary anterior single dental implant with a staged, combined surgical and prosthetic approach is discussed. Alleviation of several, but not all, risk factors eliminated the need for replacement of gingiva with pink porcelain and maintained a stable post implant host complex. PMID:24571543

Beier, Ulrike Stephanie; Strobl, Heinrich; Dhima, Matilda

2014-02-01

22

Bonded provisional restorations for esthetic soft tissue support in single-implant treatment  

Microsoft Academic Search

During the early phases of single-implant treatment, clinician needs and patient expectations can be challenging. This article describes a technique for making a simple bonded provisional restoration. In addition to minimizing patient discomfort without increasing laboratory costs, the technique enables soft tissue preservation through all treatment phases, from tooth loss to implant loading. (J Prosthet Dent 2002;87:688-91.)

Carlo E. Poggio; Antonino Salvato

2002-01-01

23

Use of an Implant O-Ring Attachment for the Tooth Supported Mandibular Overdenture: A Clinical Report  

PubMed Central

Retention of a mandibular denture can be achieved by an implant-retained or natural tooth-retained bar and stud attachment in the anterior segment of the mandible. The same design principles holds true for both implant-retained and tooth-retained methods of anchoring the bar and stud attachment. A simple and cost effective treatment for more complex implant overdenture is the concept of conventional tooth-retained overdentures. When few firm teeth still remain in a compromised dentition, preservation of these teeth for overdentures can improve retention and stability. The authors present a clinical report of a patient treated with a mandibular tooth-borne overdenture with bar and O-ring attachment. A splinted bar supported the prosthesis and an O-ring retained the denture. PMID:21769276

Guttal, Satyabodh S.; Tavargeri, Anand K.; Nadiger, Ramesh K.; Thakur, Srinath L.

2011-01-01

24

A case report of a TPS dental implant rigidly connected to a natural tooth: 19-year follow-up  

PubMed Central

Summary Aim A partial edentulous area was restored with a tooth to implant fixed partial denture and a rigid connection between the two elements. Maintenance recalls were performed over a 19-year period of observation on a yearly basis. Methods The following parameters were collected during each examination over the entire period of observation: PD around the implant and natural tooth abutment, gingival index, modified gingival index, plaque index, modified plaque index, occlusal assessment, marginal bone loss. Radiographic assessment of peri-implant bone remodeling was performed in a retrospective way. The following reference points were assessed on each image: fixture-abutment junction, threads, first contact of the crestal bone with the implant on both mesial and distal side. This made possible, with the known values for implant diameter and length, to make linear measurements of remaining peri-implant bone measured from the mesial and distal marginal bone levels and the fixture-abutment junction. The amount of bone change over the baseline to a 19 years follow-up observation time was calculated for both the implant and the natural tooth. Results Clinical parameters showed healthy values over the entire period of observation with slight isolated positive bleeding on probing. Bone remodeling values were constant over the entire period with slight higher values around the tooth. Peri-apical radiographs did not show any intrusion of the tooth. Conclusions The present case report showed the complete functionality and stability of a tooth to implant rigidly connected FPD over a period of 19 years. PMID:24611092

Quaranta, Alessandro; Poli, Ottavia; Vozza, Iole

2013-01-01

25

Optimizing Maxillary Aesthetics of a Severe Compromised Tooth through Orthodontic Movement and Dental Implants  

PubMed Central

Treatment of severe compromised tooth in the maxillary anterior area still poses great challenge to the clinicians. Several treatment modalities have been proposed to restore the function and aesthetics in teeth with advanced periodontal disease. The present study aims to report a case of traumatic injury of a left-maxillary central incisor with ridge preservation, orthodontic movement, and implant therapy. A 45-year-old woman underwent the proposed treatment for her left central incisor: basic periodontal therapy, xenogenous bone graft, and guided bone regeneration (GBR). Six months after the graft procedure, orthodontic movement by means of alignment and leveling was made and a coronal displacement of the gingival margin and vertical bone apposition could be observed after 13 months of active movement. Afterwards, a dental implant was placed followed by a connective tissue graft and immediate provisionalization of the crown. In conclusion, orthodontic movement was effective to improve the gingival tissue and alveolar bone prior to implant placement favoring the aesthetic results. Six years postoperatively, the results revealed height and width alveolar bone gain indicating that the treatment proposed was able to restore all the functional and aesthetic parameters. PMID:24523969

de Avila, Erica Dorigatti; Cirelli, Joni Augusto; Cardoso, Mauricio de Almeida; Capelozza-Filho, Leopoldino; Borelli Barros, Luiz Antonio

2014-01-01

26

Functional tooth restoration by next-generation bio-hybrid implant as a bio-hybrid artificial organ replacement therapy  

PubMed Central

Bio-hybrid artificial organs are an attractive concept to restore organ function through precise biological cooperation with surrounding tissues in vivo. However, in bio-hybrid artificial organs, an artificial organ with fibrous connective tissues, including muscles, tendons and ligaments, has not been developed. Here, we have enveloped with embryonic dental follicle tissue around a HA-coated dental implant, and transplanted into the lower first molar region of a murine tooth-loss model. We successfully developed a novel fibrous connected tooth implant using a HA-coated dental implant and dental follicle stem cells as a bio-hybrid organ. This bio-hybrid implant restored physiological functions, including bone remodelling, regeneration of severe bone-defect and responsiveness to noxious stimuli, through regeneration with periodontal tissues, such as periodontal ligament and cementum. Thus, this study represents the potential for a next-generation bio-hybrid implant for tooth loss as a future bio-hybrid artificial organ replacement therapy. PMID:25116435

Oshima, Masamitsu; Inoue, Kaoru; Nakajima, Kei; Tachikawa, Tetsuhiko; Yamazaki, Hiromichi; Isobe, Tomohide; Sugawara, Ayaka; Ogawa, Miho; Tanaka, Chie; Saito, Masahiro; Kasugai, Shohei; Takano-Yamamoto, Teruko; Inoue, Takashi; Tezuka, Katsunari; Kuboki, Takuo; Yamaguchi, Akira; Tsuji, Takashi

2014-01-01

27

Single event upsets in implantable cardioverter defibrillators  

Microsoft Academic Search

Single event upsets (SEU) have been observed in implantable cardiac defibrillators. The incidence of SEUs is well modeled by upset rate calculations attributable to the secondary cosmic ray neutron flux. The effect of recent interpretations of the shape of the heavy ion cross-section curve on neutron burst generation rate calculations is discussed. The model correlates well with clinical experience and

P. D. Bradley; E. Normand

1998-01-01

28

In vivo reactions to particulate rhenanite and particulate hydroxylapatite after implantation in tooth sockets  

Microsoft Academic Search

To gain more information on the in vivo behaviour of rhenanite (CaNaPO4), particles of this material and of hydroxylapatite were mixed with gelatin or saline and inserted in tooth sockets of beagle dogs for periods of 3 and 6 months. Rhenanite appeared to transform into an apatite containing carbonate, sodium and magnesium. Resorption of both calcium phosphate particles was not

M. M. A. Ramselaar; P. J. VAN MULLEM; W. Kalk; F. C. M. Driessens; J. R. Wijn; A. L. H. Stols

1993-01-01

29

[Preoperative planning for the placement of a single implant].  

PubMed

Radiography is of primary importance for the preoperative planning of oral implant placement. Depending on the indication, various techniques are available, each with its own merits and drawbacks. In general, it can be stated that the intra-oral radiography using the paralleling technique is the method of choice for a solitary tooth replacement. Panoramic radiography is indicated for implant placement in the symphyseal area of the lower jaw. Cross-sectional imaging is performed when information is needed in the bucco-lingual dimension. Conventional tomography is recommended for preoperative planning of limited edentulous areas. CT-scan imaging is required for rehabilitation of extended edentulous areas or in complex maxillofacial surgery combined with implant placement. Choosing the optimal technique can be performed by weighing the radiation dosage and the diagnostic information required. PMID:11930365

Jacobs, R

1999-05-01

30

Single Glucose Biofuel Cells Implanted in Rats Power Electronic Devices  

E-print Network

Single Glucose Biofuel Cells Implanted in Rats Power Electronic Devices A. Zebda1,2 , S. Cosnier1 the first implanted glucose biofuel cell (GBFC) that is capable of generating sufficient power from a mammal further developments. Following recent developments in nano- and biotechnology, state-of-the-art biofuel

Boyer, Edmond

31

Single glucose biofuel cells implanted in rats power electronic devices.  

PubMed

We describe the first implanted glucose biofuel cell (GBFC) that is capable of generating sufficient power from a mammal's body fluids to act as the sole power source for electronic devices. This GBFC is based on carbon nanotube/enzyme electrodes, which utilize glucose oxidase for glucose oxidation and laccase for dioxygen reduction. The GBFC, implanted in the abdominal cavity of a rat, produces an average open-circuit voltage of 0.57 V. This implanted GBFC delivered a power output of 38.7??W, which corresponded to a power density of 193.5??W?cm(-2) and a volumetric power of 161??W?mL(-1). We demonstrate that one single implanted enzymatic GBFC can power a light-emitting diode (LED), or a digital thermometer. In addition, no signs of rejection or inflammation were observed after 110?days implantation in the rat. PMID:23519113

Zebda, A; Cosnier, S; Alcaraz, J-P; Holzinger, M; Le Goff, A; Gondran, C; Boucher, F; Giroud, F; Gorgy, K; Lamraoui, H; Cinquin, P

2013-01-01

32

Immediate Provisionalization and Nonfunctional Loading of a Single Implant in the Maxillary Esthetic Zone: A Clinical Presentation and Parameters for Consideration  

PubMed Central

Restoration of single tooth loss with implant supported prosthesis is now considered a highly predictable treatment. However, the maxillary anterior region still presents a challenge for both the prosthodontist and the periodontist because of the inherent difficulties encountered in the provisionalization and harmonic incorporation of the definitive prosthesis into patient's dentogingival complex. This paper presents a clinical case of a single implant placed immediately after the extraction of a maxillary central incisor, followed by immediate provisionalization and nonfunctional loading. The surgical and the restorative techniques are described, and the parameters of consideration for this approach are presented. PMID:24383012

Michalakis, Konstantinos X.; Kalpidis, Christos D. R.; Kirmanidou, Yvone; Hirayama, Hiroshi; Calvani, Pasquale Lino; Pissiotis, Argiris L.

2013-01-01

33

Single and Multiple Microphone Noise Reduction Strategies in Cochlear Implants  

PubMed Central

To restore hearing sensation, cochlear implants deliver electrical pulses to the auditory nerve by relying on sophisticated signal processing algorithms that convert acoustic inputs to electrical stimuli. Although individuals fitted with cochlear implants perform well in quiet, in the presence of background noise, the speech intelligibility of cochlear implant listeners is more susceptible to background noise than that of normal hearing listeners. Traditionally, to increase performance in noise, single-microphone noise reduction strategies have been used. More recently, a number of approaches have suggested that speech intelligibility in noise can be improved further by making use of two or more microphones, instead. Processing strategies based on multiple microphones can better exploit the spatial diversity of speech and noise because such strategies rely mostly on spatial information about the relative position of competing sound sources. In this article, we identify and elucidate the most significant theoretical aspects that underpin single- and multi-microphone noise reduction strategies for cochlear implants. More analytically, we focus on strategies of both types that have been shown to be promising for use in current-generation implant devices. We present data from past and more recent studies, and furthermore we outline the direction that future research in the area of noise reduction for cochlear implants could follow. PMID:22923425

Kokkinakis, Kostas; Azimi, Behnam; Hu, Yi; Friedland, David R.

2013-01-01

34

A technique for fabricating single screw-retained implant-supported interim crowns in conjunction with implant surgery.  

PubMed

This article presents an intraoral technique for fabricating single screw-retained implant-supported interim crowns immediately after surgical implant placement in extraction sites. The technique may be used with any implant system that provides a provisional abutment or an open-tray impression coping that can be modified for use as a provisional abutment. PMID:24461941

McRory, M Eric; Cagna, David R

2014-06-01

35

Process Performance of Optima XEx Single Wafer High Energy Implanter  

NASA Astrophysics Data System (ADS)

To meet the process requirements for well formation in future CMOS memory production, high energy implanters require more robust angle, dose, and energy control while maintaining high productivity. The Optima XEx high energy implanter meets these requirements by integrating a traditional LINAC beamline with a robust single wafer handling system. To achieve beam angle control, Optima XEx can control both the horizontal and vertical beam angles to within 0.1 degrees using advanced beam angle measurement and correction. Accurate energy calibration and energy trim functions accelerate process matching by eliminating energy calibration errors. The large volume process chamber and UDC (upstream dose control) using faraday cups outside of the process chamber precisely control implant dose regardless of any chamber pressure increase due to PR (photoresist) outgassing. An optimized RF LINAC accelerator improves reliability and enables singly charged phosphorus and boron energies up to 1200 keV and 1500 keV respectively with higher beam currents. A new single wafer endstation combined with increased beam performance leads to overall increased productivity. We report on the advanced performance of Optima XEx observed during tool installation and volume production at an advanced memory fab.

Kim, J. H.; Yoon, Jongyoon; Kondratenko, S.; David, J.; Rubin, L. M.; Jang, I. S.; Cha, J. C.; Joo, Y. H.; Lee, A. B.; Jin, S. W.

2011-01-01

36

Biomaterial Selection for Tooth Regeneration  

PubMed Central

Biomaterials are native or synthetic polymers that act as carriers for drug delivery or scaffolds for tissue regeneration. When implanted in vivo, biomaterials should be nontoxic and exert intended functions. For tooth regeneration, biomaterials have primarily served as a scaffold for (1) transplanted stem cells and/or (2) recruitment of endogenous stem cells. This article critically synthesizes our knowledge of biomaterial use in tooth regeneration, including the selection of native and/or synthetic polymers, three-dimensional scaffold fabrication, stem cell transplantation, and stem cell homing. A tooth is a complex biological organ. Tooth loss represents the most common organ failure. Tooth regeneration encompasses not only regrowth of an entire tooth as an organ, but also biological restoration of individual components of the tooth including enamel, dentin, cementum, or dental pulp. Regeneration of tooth root represents perhaps more near-term opportunities than the regeneration of the whole tooth. In the adult, a tooth owes its biological vitality, arguably more, to the root than the crown. Biomaterials are indispensible for the regeneration of tooth root, tooth crown, dental pulp, or an entire tooth. PMID:21699433

Yuan, Zhenglin; Nie, Hemin; Wang, Shuang; Lee, Chang Hun; Li, Ang; Fu, Susan Y.; Zhou, Hong

2011-01-01

37

Chromium single photon emitters in diamond fabricated by ion implantation  

E-print Network

Controlled fabrication and identification of bright single photon emitters is at the heart of quantum optics and materials science. Here we demonstrate a controlled engineering of a chromium bright single photon source in bulk diamond by ion implantation. The Cr center has fully polarized emission with a ZPL centered at 749 nm, FWHM of 4 nm, an extremely short lifetime of ~1 ns, and a count rate of 500 kcounts/s. By combining the polarization measurements and the vibronic spectra, a model of the center has been proposed consisting of one interstitial chromium atom with a transition dipole along one of the directions.

Igor Aharonovich; Stefania Castelletto; Brett C. Johnson; Jeffrey C. McCallum; David A. Simpson; Andrew D. Greentree; Steven Prawer

2010-01-25

38

Chromium single photon emitters in diamond fabricated by ion implantation  

E-print Network

Controlled fabrication and identification of bright single photon emitters is at the heart of quantum optics and materials science. Here we demonstrate a controlled engineering of a chromium bright single photon source in bulk diamond by ion implantation. The Cr center has fully polarized emission with a ZPL centered at 749 nm, FWHM of 4 nm, an extremely short lifetime of ~1 ns, and a count rate of 500 kcounts/s. By combining the polarization measurements and the vibronic spectra, a model of the center has been proposed consisting of one interstitial chromium atom with a transition dipole along one of the directions.

Aharonovich, Igor; Johnson, Brett C; McCallum, Jeffrey C; Simpson, David A; Greentree, Andrew D; Prawer, Steven

2010-01-01

39

Short implants supporting single crowns in atrophic jaws.  

PubMed

Data sourcesPubMed-Medline, Web of Science, Cochrane Library, ProQuest Dissertations and Theses, LILACS, Ebsco-Dentistry and Oral Sciences Source, Scirus, Embase, Scopus and Journal Ovid databases were searched. In addition hand searching of 14 relevant journals was undertaken along with screening of the reference lists of screened article and reviews.Study selectionRandomised controlled clinical trials (RCTs), controlled clinical trials (CCTs), prospective cohort studies and case series were included. Studies where short (<10 mm) implants were placed in non-augmented healed alveolar bone with a minimum of ten implants and follow up of one year were consideredData extraction and synthesisOne reviewer carried out the quality assessment. Implant level data were analysed. Meta-analyses were conducted and meta-regression analyses were run as fixed-effect models.ResultsTwenty-one articles reporting 16 studies (ten cohorts and six case series) were included. Seven hundred and sixty-two short implants were followed up for up to 120 months in 360 patients (mean follow-up: 44 ± 33.72 months; mean dropout rate: 5.1%). The means failure proportion (FP), biological failure proportion (BFP), prosthetic failure proportion (PFP) and radiographic marginal bone loss (MBL) were 5.9% (95% CI: 3.7-9.2%), 3.8% (95%CI: 1.9-7.4%), 2.8% (95%CI: 1.4-5.7%) and 0.83 mm (95%CI: 0.54-1.12 mm) respectively. Quantitative analysis showed that placement in the mandible (p = 0.0002) and implants with length ?8 mm (p = 0.01) increased FP, BFP and MBL, whereas qualitative assessment revealed that crown-to-implant ratio did not influence MBL.ConclusionsWithin the limitations of the present systematic review with meta-analysis, it is suggested that single crowns supported by short implants are an acceptable and predictable option in the short- and long-term treatment of the atrophic jaws. PMID:25343396

Al-Ansari, Asim

2014-09-01

40

Single Tooth Replacement Using InCeram Resin Bonded Fixed Partial Denture: A Clinical Report  

PubMed Central

This clinical report describes a treatment option for replacement of a missing mandibular anterior tooth using InCeram resin bonded fixed partial denture (RBFPD). The conventional approach for replacing mandibular incisors dictates the placement of either a conventional porcelain-fused-to-metal (PFM) bridge, Maryland bridge, or fiber-reinforced composite veneer bridge and several appearance-related disadvantages have been reported in the use of a prosthesis that incorporates a metal substructure. The InCeram bridge is a minimally invasive restoration and eliminates undesirable incisal graying frequently observed in metal RBFPDs. This method was successfully clinically applied to overcome shortcomings of other approaches that may require a minimal invasive technique to preserve lasting sound tooth structure. PMID:24910683

Moslehifard, Elnaz; Farid, Farzaneh

2014-01-01

41

Single Tooth Replacement Using InCeram Resin Bonded Fixed Partial Denture: A Clinical Report.  

PubMed

This clinical report describes a treatment option for replacement of a missing mandibular anterior tooth using InCeram resin bonded fixed partial denture (RBFPD). The conventional approach for replacing mandibular incisors dictates the placement of either a conventional porcelain-fused-to-metal (PFM) bridge, Maryland bridge, or fiber-reinforced composite veneer bridge and several appearance-related disadvantages have been reported in the use of a prosthesis that incorporates a metal substructure. The InCeram bridge is a minimally invasive restoration and eliminates undesirable incisal graying frequently observed in metal RBFPDs. This method was successfully clinically applied to overcome shortcomings of other approaches that may require a minimal invasive technique to preserve lasting sound tooth structure. PMID:24910683

Moslehifard, Elnaz; Farid, Farzaneh

2014-01-01

42

Advances in cross-contamination control using single-wafer, high-current implantation  

Microsoft Academic Search

The Varian VIISta 80 is a single-wafer high-current implanter, which uses a ribbon beam and a single-direction mechanical scan for implantation. The placement of the wafers on an electrostatic platen, and the absence of end station parts in the vicinity of the wafer during implant, translate into an expected advantage in implanter memory over batch tools. This paper focuses on

S. S. Todorov; A. Bertuch; W. Piscitello; R. Eddy; T. Robertson

2000-01-01

43

A Conservative Treatment Approach to Replacing a Missing Anterior Tooth  

PubMed Central

An implant-supported crown or conventionally fixed partial denture is the most common treatment modality to replace a missing anterior tooth but a more conservative approach, with a fiber reinforced composite resin FPD, can be used to replace a missing anterior tooth in young patients or when the patient does not agree for an implant, or conventional FPD or RPD therapy. It is an esthetic, conservative single sitting chairside procedure which can be used as a definitive treatment alternative in certain clinical situations for esthetic and functional replacement of a missing anterior tooth. To achieve desirable results, putty matrix was used for proper positioning of the pontic during direct fabrication of FRCFPD. PMID:25254122

Singh, Kunwarjeet; Gupta, Nidhi; Unnikrishnan, Nandini; Kapoor, Vikram; Arora, Dhruv; Khinnavar, Poonam K.

2014-01-01

44

Metal-reinforced single implant mandibular overdenture retained by an attachment: a clinical report.  

PubMed

Results of studies have shown that a single implant mandibular overdenture significantly increases the satisfaction and quality of life of patients with edentulism. The single implant-retained overdenture has the additional advantage of being less expensive and invasive than a 2-implant supported overdenture but has a high incidence of fracture of the acrylic resin base at the point of the implant. The treatment, design, and fabrication of a metal-reinforced single-implant mandibular overdenture with the Locator attachment as a retention device is described. PMID:24199604

Grageda, Edgar; Rieck, Bastian

2014-01-01

45

A single histrelin implant is effective for 2 years for treatment of central precocious puberty.  

PubMed

We investigated whether a "yearly" histrelin implant would provide pubertal suppression when left in place for 2 years. Equivalent suppression was observed when comparing 12 and 24 months in 33 children with central precocious puberty. A single implant for 2 years reduces cost and number of implant procedures. PMID:23809043

Lewis, Katherine A; Goldyn, Andrea K; West, Karen W; Eugster, Erica A

2013-10-01

46

Cochlear implantation and management of chronic suppurative otitis media: single stage procedure?  

PubMed

In a series of 360 patients who underwent cochlear implantation at our center, four patients (five procedures) had cochlear implantation with obliteration of the mastoid cavity and management of cholesteatoma as a single-staged procedure. Three patients were bilaterally deaf secondary to CSOM and had bilateral mastoid cavities, and in one patient congenital cholesteatoma was identified during cochlear implantation. A mastoidectomy or revision mastoidectomy with obliteration of the mastoid cavity and cochlear implantation was performed as a single stage procedure. Cholesteatoma reoccurred in one patient 9 years after cochlear implantation. Surgical procedures, complications, follow-up and outcomes are discussed. PMID:15756568

Basavaraj, S; Shanks, M; Sivaji, N; Allen, Agnes A

2005-10-01

47

Deep-level defects study of arsenic-implanted ZnO single crystal  

Microsoft Academic Search

Unintentionally doped n-type zinc oxide (ZnO) single crystal was implanted by arsenic ions with fluence of 1014cm?2 at room temperature followed by post-implantation annealing up to 900°C. Rectifying property was not observed in the As-implanted or the post-implantation annealed samples. Au Schottky contact was fabricated on the samples with the H2O2 pre-treatment. Deep-level transient spectroscopy measurements were performed on the

C. Y. Zhu; C. C. Ling; G. Brauer; W. Anwand; W. Skorupa

2009-01-01

48

Fatigue resistance of two implant\\/abutment joint designs  

Microsoft Academic Search

Statement of Problem. Because of reported mechanical failures, alternative implant system components with suggested optimized strength have been manufactured. However, the endurance of these products has not been well investigated. Purpose. This study was designed to assess the effect of joint design on the fatigue strength and failure mode of 2 single-tooth implant systems: Brånemark and ITI, in which a

Ameen Khraisat; Roxana Stegaroiu; Shuichi Nomura; Osamu Miyakawa

2002-01-01

49

Creating a Single-Visit, Fibre-Reinforced, Composite Resin Bridge by Using a Natural Tooth Pontic: A Viable Alternative to a PFM Bridge  

PubMed Central

Background: The rehabilitation of an anterior tooth space presents a confronting situation. Several modalities are presently available to address the challenge of an immediate replacement of a missing anterior tooth. These include a removable temporary acrylic prosthesis or resin-bonded bridges. Fibre-Reinforced Composite (FRC) bridges are preferable if they are fixed and if a cost-effective tooth replacement is desired. Also, they provide an aesthetic and a conservative treatment choice as the abutment teeth require a minimal or no preparation. Methods: This article is describing two cases with an immediate replacement of the maxillary incisor teeth by a single visit technique, with the use of FRC Resin (Ribbond) bridges and natural tooth crowns as pontics. Results and Conclusions: The procedure was completed at the chair side, thereby avoiding the laboratory costs. A two year follow up of the cases has shown a successful outcome. Creating an adhesive FRC bridge by using a natural tooth pontic is a successful treatment option for the direct aesthetic replacement of missing anterior teeth. PMID:23730674

Khetarpal, Ambica; Talwar, Sangeeta; Verma, Mahesh

2013-01-01

50

Different responses to muon implantation in single- and double-stranded DNA  

Microsoft Academic Search

A model-free analysis of the longitudinal muon spin relaxation of muons implanted into single- and double-stranded DNA samples is reported. These samples show distinctly different responses to implanted muons with discontinuities of the integrated asymmetries at temperatures where these molecules are likely to have onset of molecular and electron dynamics.

Penny L. Hubbard; Akiko Tani; Vasily S. Oganesyan; Julea N. Butt; Stephen P. Cottrell; Upali A. Jayasooriya

2006-01-01

51

Subcutaneous Single-Incision Implantation of Cardioverter-Defibrillators Under Local Anesthesia by Electrophysiologists in the Electrophysiology Laboratory  

Microsoft Academic Search

Implantable cardioverter-defibrillators (ICDs) have traditionally been implanted at the operating room under general anesthesia. Endocardial lead systems and downsized devices allowed implantation by electrophysiologists in the pectoral region. The present study evaluates the safety and efficacy of subcutaneous ICD implantation performed entirely by electrophysiologists using a single-incision approach for lead insertion and device placement under local anesthesia. Between June 1996

F. Paul van Rugge; Lucas H Savalle; Martin J Schalij

1998-01-01

52

Who Is an Implant Candidate?  

MedlinePLUS

Who Is an Implant Candidate? If you're interested in replacing a missing tooth or teeth, dental implants may be an option for you. Most people are good candidates for implants. A good candidate should have the following: Healthy ...

53

Mandibular overdentures anchored to single implants: A five-year prospective study  

Microsoft Academic Search

Statement of problem. It is unknown what minimum number of implants are required to satisfactorily support and retain a mandibular overdenture.Purpose. The purpose of this study was to evaluate a treatment modality by using mandibular overdentures anchored to single implants in a geriatric patient population.Material and methods. Twenty-one patients with a mean age of 74.2 years were treated with single

Giampiero Cordioli; Zeina Majzoub; Stefano Castagna

1997-01-01

54

Nanomechanical characterization of cavity growth and rupture in hydrogen-implanted single-crystal BaTiO3  

E-print Network

Nanomechanical characterization of cavity growth and rupture in hydrogen-implanted single formation is related to the measured mechanical properties to better understand hydrogen implantation- tions in capacitors and gate dielectrics for nonvolatile ran- dom access memory NVRAM devices, actuators

Atwater, Harry

55

Tooth Abrasion and Tooth Erosion  

MedlinePLUS

... protects the innermost part of the tooth, the pulp, which contains nerves and blood vessels. Abrasion and erosion also can affect how your teeth look. Diagnosis Your dentist can examine your teeth ...

56

Formation of oriented nickel aggregates in rutile single crystals by Ni implantation  

NASA Astrophysics Data System (ADS)

The magnetic and electrical properties of Ni implanted single crystalline TiO2 rutile were studied for nominal implanted fluences between 0.5×1017 cm-2 and 2.0×1017 cm-2 with 150 keV energy, corresponding to maximum atomic concentrations between 9 at% and 27 at% at 65 nm depth, in order to study the formation of metallic oriented aggregates. The results indicate that the as implanted crystals exhibit superparamagnetic behavior for the two higher fluences, which is attributed to the formation of nanosized nickel clusters with an average size related with the implanted concentration, while only paramagnetic behavior is observed for the lowest fluence. Annealing at 1073 K induces the aggregation of the implanted nickel and enhances the magnetization in all samples. The associated anisotropic behavior indicates preferred orientations of the nickel aggregates in the rutile lattice consistent with Rutherford backscattering spectrometry—channelling results. Electrical conductivity displays anisotropic behavior but no magnetoresistive effects were detected.

Cruz, M. M.; da Silva, R. C.; Pinto, J. V.; Borges, R. P.; Franco, N.; Casaca, A.; Alves, E.; Godinho, M.

2013-08-01

57

Evolution of hydrogen and helium co-implanted single-crystal silicon during annealing  

NASA Astrophysics Data System (ADS)

H+ was implanted into single-crystal silicon with a dose of 1×1016/cm2 and an energy of 30 KeV, and then He+ was implanted into the same sample with the same dose and an energy of 33 KeV. Both of the implantations were performed at room temperature. Subsequently, the samples were annealed in a temperature range from 200 to 450 °C for 1 h. Cross-sectional transmission electron microscopy, Rutherford backscattering spectrometry/channeling, elastic recoil detection, and high resolution x-ray diffraction were employed to characterize the strain, defects, and the distribution of H and He in the samples. The results showed that co-implantation of H and He decreases the total implantation dose, with which the surface could exfoliate during annealing. During annealing, the distribution of hydrogen did not change, but helium moved deeper and its distribution became sharper. At the same time, the maximum of the strain in the samples decreased a lot and also moved deeper. Furthermore, the defects introduced by ion implantation and annealing were characterized by slow positron annihilation spectroscopy, and two positron trap peaks were found. After annealing, the maximum of these two peaks decreased at the same time and their positions moved towards the surface. No bubbles or voids but cracks and platelets were observed by cross-sectional transmission electron microscopy. Finally, the relationship between the total implantation dose and the fraction of hydrogen in total implantation dose was calculated.

Duo, Xinzhong; Liu, Weili; Zhang, Miao; Wang, Lianwei; Lin, Chenglu; Okuyama, M.; Noda, M.; Cheung, Wing-Yiu; Wong, S. P.; Chu, Paul K.; Hu, Peigang; Wang, S. X.; Wang, L. M.

2001-10-01

58

Iridium 192 nomogram system for single plane implants  

SciTech Connect

Nomograms for square planar arrays spanning the range from 3 X 3 cm to 10 X 10 cm were developed. The nomograms are intended to be used for pretreatment planning of implant geometry, so that the therapist may enter the operating room with a plan for the optimal implant in mind. We show that clinically useful implants are those in which the reference isodoses are fully coupled. Decoupling occurs when ribbon spacing exceeds approximately 1.2 cm and leads to undesirable ''cold spots'' within the treatment volume. Ribbon spacing of 1.0 cm is recommended. This represents a trade-off between adequate ribbon coupling and minimum tissue damage from trocar placement. For clinically useful arrays, the area enclosed by the reference isodose contour (85% of the maximum dose rate) is approximately 50% of the array area. Reference isodose contour and its enclosed area are independent of seed strength for a given array, as long as all seeds within the array are of equal strength.

Murphy, D.J. Jr.; Memula, N.; Doss, L.L.

1986-02-01

59

Deep level transient spectroscopic study of oxygen-implanted ZnO single crystal  

Microsoft Academic Search

ZnO single crystal samples were implanted by oxygen with the energy of 150keV. After the pretreatment of hydrogen peroxide [1], Schottky contacts were fabricated with Au film deposited by thermal evaporation. Deep level defects were studied by deep level transient spectroscopy (DLTS). The activation energy of the 0.29eV deep trap was observed in the as-implanted sample and samples anneal at

Ziran Ye; Guangwei Ding; Jincheng Fan; Chi Chung Ling

2011-01-01

60

Tooth Discoloration  

MedlinePLUS

... remove the inner part of the tooth (the pulp) before it has a chance to decay and darken. However, teeth that have root canal treatment may darken anyway. To prevent intrinsic stains in children, avoid too much early exposure to fluorides. Once ...

61

Single crystalline BaTiO3 thin films synthesized using ion implantation induced layer transfer  

NASA Astrophysics Data System (ADS)

Layer transfer of BaTiO3 thin films onto silicon-based substrates has been investigated. Hydrogen and helium ions were co-implanted to facilitate ion-implantation-induced layer transfer of films from BaTiO3 single crystals. From thermodynamic equilibrium calculations, we suggest that the dominant species during cavity nucleation and growth are H2, H+, H2O, Ba2+ and Ba-OH, and that the addition of hydrogen to the Ba-Ti-O system can effectively suppress volatile oxide formation during layer transfer and subsequent annealing. After ion implantation, BaTiO3 layers contain microstructural defects and hydrogen precipitates in the lattice, but after layer transfer, the single crystal is found to be stoichiometric. Using direct wafer bonding and layer splitting, single crystal BaTiO3 thin films were transferred onto amorphous Si3N4 and Pt substrates. Micro-Raman spectroscopy indicated that the density of defects generated by ion implantation in BaTiO3 can be significantly reduced during post-transfer annealing, returning the transferred layer to its single crystal state. Characterization using piezoresponse force microscopy shows that the layer transferred thin films are ferroelectric, with domain structures and piezoresponse characteristics similar to that of bulk crystals.

Park, Young-Bae; Diest, Kenneth; Atwater, Harry A.

2007-10-01

62

Chromium single-photon emitters in diamond fabricated by ion implantation  

Microsoft Academic Search

Controlled fabrication and identification of bright single-photon emitters is at the heart of quantum optics. Here we demonstrate controlled engineering of a chromium bright single-photon source in bulk diamond by ion implantation. The Cr center has fully polarized emission with a zero-phonon line centered at 749 nm, full width at half maximum of 4 nm, an extremely short lifetime of

Igor Aharonovich; Stefania Castelletto; Brett C. Johnson; Jeffrey C. McCallum; David A. Simpson; Andrew D. Greentree; Steven Prawer

2010-01-01

63

Magnetic and transport properties of transition-metal implanted ZnO single crystals  

NASA Astrophysics Data System (ADS)

ZnO single crystals were implanted with Mn, Co and Ni with fluences between 1 × 1016 cm-2 and 1 × 1017 cm-2 and energy of 200 keV. Results indicate that aggregation of transition metal ions in the as implanted state occurs only in the case of Ni. After an annealing stage to recover the ZnO structure aggregation occurs for the higher fluences of all implanted species. For lower concentrations paramagnetic behaviour with magnetic moments close to those of individual ions is observed. No polarised impurity band is formed as a result of the presence of transition metal ions and all samples show electrical conduction by carriers in extended states of ZnO. Significant values of magnetoresistance are measured at low temperatures, where electrical transport is described by hopping mechanisms between localized states. The sign of the magnetoresistance is dependent of the doping ion and is correlated with the observed aggregation.

Borges, R. P.; Ribeiro, B.; Costa, A. R. G.; Silva, C.; da Silva, R. C.; Evans, G.; Gonçalves, A. P.; Cruz, M. M.; Godinho, M.

2011-01-01

64

Peroperative fractures in uncemented total hip arthrography: results with a single design of stem implant  

PubMed Central

The incidence of intraoperative femoral fractures with a single design of stem implant, the Meridian (Stryker-Howmedica, Rutherford, N.J.), has been assessed in a study of 117 implants in patients treated consecutively between 1996 and 2001. The aim of the study was to evaluate the risk factors for suffering an intraoperative fracture and to determine, based on a short-term follow-up, if there were radiographic signs of early loosening. The following variables were analysed: demographic factors of the patient, morphology of the femur, intraoperative factors and postoperative radiographic factors. The radiographic stability of the implant and the presence of early signs of loosening were evaluated 2 years after surgery. The incidence of femoral fractures was 11% (13 cases in 117 implants), which is higher that reported in earlier published studies, and there was an increased number of fractures when the proximal filling of the femoral canal was higher. Although there was no statistically significant relation between the variables studied and the appearance of an intraoperative fracture, we conclude that the appearance of a femoral intraoperative fracture did not affect the radiographic stability of the implant during the short-term follow-up of our study cohort. PMID:17237945

Garcia-Elias, Elena; Gil-Garay, Enrique

2007-01-01

65

Electrical and photoluminescence properties of carbon implanted ZnO bulk single crystals  

NASA Astrophysics Data System (ADS)

Carbon-ions, which are expected as an amphoteric impurity, are implanted into ZnO bulk single crystals with a fluence of 1.5 × 10 15 cm -2. The carbon-ion implanted ZnO shows the n-type conductivity and the resistivity varies from 6 × 10 4 ? cm (for unimplanted samples) to 3 × 10 -2 ? cm (for 800 °C-annealed ones). The Rutherford backscattering (RBS) studies show the existence of the displaced zinc atoms. In photoluminescence (PL) measurements, the broad emission at 2.34 eV observed in un-implanted and as-implanted samples is related to oxygen vacancy and zinc interstitial. After annealing, the weak PL-emission related to carbon donor is observed at 3.06 eV, indicating that the donor level lies at ˜310 meV below the conduction band. The carbon-ion implanted ZnO layer with the low resistivity achieved in the present study suggests the possibility of transparent conductive oxide.

Matsumoto, K.; Kuriyama, K.; Kushida, K.

2009-05-01

66

An overview of immediate root analogue zirconia implants.  

PubMed

Owing to its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia has the potential to become a substitute for titanium as dental implant material and to be successfully used as root-analogue implants by reproducing the contours of the extracted tooth. This article presents an overview of the technique of using root analogue zirconia dental implants as an immediate implantation material. These implants are replicas of the extracted tooth and therefore truly anatomically correct and socket friendly. PMID:21905912

Regish, K M; Sharma, Deeksha; Prithviraj, D R

2013-04-01

67

High-Sensitivity Temperature Sensing Using an Implanted Single Nitrogen-Vacancy Center Array in Diamond  

E-print Network

We presented a high-sensitivity temperature detection using an implanted single Nitrogen-Vacancy center array in diamond. The high-order Thermal Carr-Purcell-Meiboom-Gill (TCPMG) method was performed on the implanted single nitrogen vacancy (NV) center in diamond in a static magnetic field. We demonstrated that under small detunings for the two driving microwave frequencies, the oscillation frequency of the induced fluorescence of the NV center equals approximately to the average of the detunings of the two driving fields. On basis of the conclusion, the zero-field splitting D for the NV center and the corresponding temperature could be determined. The experiment showed that the coherence time for the high-order TCPMG was effectively extended, particularly up to 108 {\\mu}s for TCPMG-8, about 14 times of the value 7.7 {\\mu}s for thermal Ramsey method. This coherence time corresponded to a thermal sensitivity of 10.1 mK/Hz1/2. We also detected the temperature distribution on the surface of a diamond chip in three different circumstances by using the implanted NV center array with the TCPMG-3 method. The experiment implies the feasibility for using implanted NV centers in high-quality diamonds to detect temperatures in biology, chemistry, material science and microelectronic system with high-sensitivity and nanoscale resolution.

Junfeng Wang; Fupan Feng; Jian Zhang; Jihong Chen; Zhongcheng Zheng; Liping Guo; Wenlong Zhang; Xuerui Song; Guoping Guo; Lele Fan; Chongwen Zou; Liren Lou; Wei Zhu; Guanzhong Wang

2014-10-25

68

Chick tooth induction revisited.  

PubMed

Teeth have been missing from Aves for almost 100 million years. However, it is believed that the avian oral epithelium retains the molecular signaling required to induce odontogenesis, and this has been widely examined using heterospecific recombinations with mouse dental mesenchyme. It has also been argued that teeth can form from the avian oral epithelium owing to contamination of the mouse mesenchyme with mouse dental epithelial cells. To investigate the possibility of tooth formation from chick oral epithelium and the characteristics of possible chick enamel, we applied LacZ transgenic mice during heterospecific recombination and examined the further tooth formation. Transmission electron microscopy was used to identify the two tissues during development after heterospecific recombination. No mixing was detected between chick oral epithelium and mouse dental mesenchyme after 2 days, and secretory ameloblasts with Tomes' processes were observed after 1 week. Teeth were formed after 3 weeks with a single cusp pattern, possibly determined by epithelial factors, which is similar to that of the avian tooth in the late Jurassic period. These recombinant teeth were smaller than mouse molars, whereas perfect structures of both ameloblasts and enamel showed histological characteristics similar to those of mice. Together these observations consistent with previous report that odontogenesis is initially directed by species-specific mesenchymal signals interplaying with common epithelial signals. PMID:19226602

Cai, Jinglei; Cho, Sung-Won; Ishiyama, Mikio; Mikami, Masato; Hosoya, Akihiro; Kozawa, Yukishige; Ohshima, Hayato; Jung, Han-Sung

2009-07-15

69

Outcome of single-stage breast reconstruction using the natrelle 150 expander implant.  

PubMed

The Natrelle 150 offers the advantage of single-stage reconstruction. However, there is lack of published data on its long term outcomes, which does not allow for definitive conclusions as to whether it truly meets its design objective of a lasting single stage breast reconstruction. This is a retrospective review of all Natrelle 150 reconstructions by a single surgeon over 5 years. A total of 143 procedures were performed in 125 patients with a mean follow-up of 33 months (range, 3-65 months). Most (120, 84%) received the implant after oncological mastectomies, 22 (15%) after risk-reducing mastectomies, and 1 (0.8%) for hypoplasia. Fifty-one (35.7%) implants were explanted an average of 12.9 months after implantation. A Kaplan-Meier survival analysis demonstrates an explantation rate of 25% by 11 months. Explantation was more likely after subpectoral placement compared to reconstructions in combination with latissimus dorsi flaps (P < 0.05). Risk-reducing reconstructions were also more likely to undergo explantation (P < 0.05) compared to reconstructions for oncological reasons. Our data suggest that this prosthesis is only successful as a 1-stage procedure in certain patients, and has led to more careful patient selection and counseling. PMID:23856753

Teo, Isabel; Azmy, Iman A

2014-11-01

70

Implantation of a fully subcutaneous ICD in a patient with single ventricle morphology and Eisenmenger physiology.  

PubMed

Implantable cardioverter-defibrillator (ICD) therapy has been adopted increasingly in congenital heart disease. However, in patients with intracardiac right-to-left shunting the use of standard transvenous ICD lead systems is relatively contraindicated due to the increased risk of systemic thromboembolism. In this constellation, a recently introduced totally subcutaneous ICD system (S-ICD) seems to be a good and minimal invasive alternative to conventional epicardial ICD therapy. Here we describe the first use of this S-ICD in a patient with single ventricle and Eisenmenger physiology. In this unusual cardiac anatomy modification of the standard implantation technique by use of short sequences of fluoroscopy helped to ensure exact electrode and can placement and thus regular function of the S-ICD system. PMID:22998005

Peters, Bjoern; Will, Achim; Berger, Felix; Butter, Christian

2012-08-01

71

MIND+ system; More universal dose patterns by single-step ion implantation  

NASA Astrophysics Data System (ADS)

Electrical characteristics of semi-conductor devices within a wafer are expected to be uniform based on control of the dose pattern during the ion implant process. SEN developed the MIND system (Mapping of Intentional Non-uniform Dosage), to provide such dose pattern control. This capability has been enhanced with MIND+. The new system provides improved two-dimensional dose pattern control with more degrees of freedom and greater accuracy than the original MIND system. In addition, MIND+ can generate practical dose patterns (see below) while using a single step implant. As a result, MIND+ provides a very powerful tool for yield enhancement without sacrificing throughput. This paper will provide more detail on the capabilities and practical applications of the MIND+ system.

Okamoto, Yasuharu; Ninomiya, Shiro; Ochi, Akihiro; Ueno, Yusuke; Yamada, Tatsuya; Kimura, Yasuhiko; Kudo, Tetsuya; Koike, Masazumi; Suetsugu, Noriyuki; Ookita, Yoshiaki; Tsukihara, Mitsukuni; Sato, Fumiaki; Fuse, Genshu; Ueno, Kazuyoshi; Sugitani, Michiro

2012-11-01

72

Familial tooth bone graft for ridge and sinus augmentation: a report of two cases  

PubMed Central

Recently, clinical application of autogenous tooth bone-graft materials has been reported. Autogenous tooth bone graft has been used in implant surgery. Familial tooth bone graft is a more advanced procedure than autogenous teeth bone graft in that extracted teeth can be used for bone graft materials of implant and teeth donation between siblings is possible. We used autogenous tooth and familial tooth bone-graft materials for ridge augmentation and sinus bone graft and obtained satisfactory results. The cases are presented herein. PMID:24627842

Kim, Young-Kyun; Lim, Sung-Chul

2014-01-01

73

Single- and Multi-Channel Modulation Detection in Cochlear Implant Users  

PubMed Central

Single-channel modulation detection thresholds (MDTs) have been shown to predict cochlear implant (CI) users’ speech performance. However, little is known about multi-channel modulation sensitivity. Two factors likely contribute to multichannel modulation sensitivity: multichannel loudness summation and the across-site variance in single-channel MDTs. In this study, single- and multi-channel MDTs were measured in 9 CI users at relatively low and high presentation levels and modulation frequencies. Single-channel MDTs were measured at widely spaced electrode locations, and these same channels were used for the multichannel stimuli. Multichannel MDTs were measured twice, with and without adjustment for multichannel loudness summation (i.e., at the same loudness as for the single-channel MDTs or louder). Results showed that the effect of presentation level and modulation frequency were similar for single- and multi-channel MDTs. Multichannel MDTs were significantly poorer than single-channel MDTs when the current levels of the multichannel stimuli were reduced to match the loudness of the single-channel stimuli. This suggests that, at equal loudness, single-channel measures may over-estimate CI users’ multichannel modulation sensitivity. At equal loudness, there was no significant correlation between the amount of multichannel loudness summation and the deficit in multichannel MDTs, relative to the average single-channel MDT. With no loudness compensation, multichannel MDTs were significantly better than the best single-channel MDT. The across-site variance in single-channel MDTs varied substantially across subjects. However, the across-site variance was not correlated with the multichannel advantage over the best single channel. This suggests that CI listeners combined envelope information across channels instead of attending to the best channel. PMID:24918605

Galvin, John J.; Oba, Sandy; Fu, Qian-Jie; Ba?kent, Deniz

2014-01-01

74

Towards a single-chip, implantable RFID system: is a single-cell radio possible?  

PubMed Central

We present an overview of progress towards single-chip RFID solutions. To date heterogeneous integration has been appropriate for non-biological systems. However, for in-vivo sensors and even drug delivery systems, a small form factor is required. We discuss fundamental limits on the size of the form factor, the effect of the antenna, and propose a unified single-chip RFID solution appropriate for a broad range of biomedical in-vivo device applications, both current and future. Fundamental issues regarding the possibility of single cell RF radios to interface with biological function are discussed. PMID:19169827

Rutherglen, Christopher

2009-01-01

75

Irradiation-induced microstructural change in helium-implanted single crystal and nano-engineered SiC  

NASA Astrophysics Data System (ADS)

Microstructural evolution induced by helium implantation and subsequent heavy ion irradiation has been investigated in single crystal and nano-engineered (NE) 3C SiC. Implantation with 65 keV He+ ions was performed at 277 °C, and the helium depth distribution was determined by elastic recoil detection analysis (ERDA). Transmission electron microscopy (TEM) could not resolve the presence of bubbles in any of the helium-implanted single crystal SiC. However, helium platelets and small dislocation loops (?50 nm in diameter) were observed in the single crystal sample with the highest implantation fluence after 1 h annealing at 700 °C. Following irradiation with 9 MeV Au3+ ions at 700 °C, no bubbles were observed in the helium-implanted single crystal SiC, regardless of helium fluence. For the helium-implanted NE SiC, subsequent irradiation with 9 MeV Au ions to a dose of 10 dpa at 700 °C resulted in the formation and growth of bubbles, and a bimodal helium bubble size distribution was observed at the highest helium concentration (8000 appm) in the NE SiC.

Chen, C. H.; Zhang, Y.; Fu, E.; Wang, Y.; Crespillo, M. L.; Liu, C.; Shannon, S.; Weber, W. J.

2014-10-01

76

Seal Out Tooth Decay  

MedlinePLUS

... for getting sealants is to avoid tooth decay. Fluoride in toothpaste and in drinking water protects the ... other ways to prevent tooth decay? Yes. Using fluoride toothpaste and drinking fluoridated water can help protect ...

77

Perspective Molecular Tooth Decay  

E-print Network

Perspective Molecular Tooth Decay Rob DeSalle* American Museum of Natural History, New York, New.0), is used as an indicator of functionality. Brush Your Branches-- Molecular Tooth Decay When the branches in tooth structure, as it forms the outer cap of teeth. It preserves extremely well in the fossil record

DeSalle, Rob

78

Paramagnetism and antiferromagnetic interactions in single-phase Fe-implanted ZnO.  

PubMed

As the intrinsic origin of the high-temperature ferromagnetism often observed in wide-gap dilute magnetic semiconductors becomes increasingly debated, there is a growing need for comprehensive studies on the single-phase region of the phase diagram of these materials. Here we report on the magnetic and structural properties of Fe-doped ZnO prepared by ion implantation of ZnO single crystals. A detailed structural characterization shows that the Fe impurities substitute for Zn in ZnO in a wurtzite Zn(1-x)Fe(x)O phase which is coherent with the ZnO host. In addition, the density of beam-induced defects is progressively decreased by thermal annealing up to 900 ° C, from highly disordered after implantation to highly crystalline upon subsequent annealing. Based on a detailed analysis of the magnetometry data, we demonstrate that isolated Fe impurities occupying Zn-substitutional sites behave as localized paramagnetic moments down to 2 K, irrespective of the Fe concentration and the density of beam-induced defects. With increasing local concentration of Zn-substitutional Fe, strong nearest-cation-neighbor antiferromagnetic interactions favor the antiparallel alignment of the Fe moments. PMID:24025311

Pereira, L M C; Wahl, U; Correia, J G; Van Bael, M J; Temst, K; Vantomme, A; Araújo, J P

2013-10-16

79

A 48-month multicentric clinical investigation: implant design and survival.  

PubMed

This report is based on a total of 2,955 implants of 6 different designs, randomized and placed in 829 patients and followed for 48 months. Implant failure was defined as nonintegration at uncovering or removal due to mobility, persistent pain, infection, and evidence of radiographic bone loss. Failures were reported for 3 phases of treatment: implant placement to uncovering (phase 1), uncovering to loading (phase 2), and postloading (phase 3). Differences in survival were compared with Kaplan-Meier survival curves. The maxillary single tooth application resulted in 95.2% survival for the hydroxyapatite-coated grooved implants. In the maxillary completely edentulous application, survival of hydroxyapatite grooved and screw implants were considerably better compared with the titanium screw implants. The hydroxyapatite-coated cylinder had better survival than the titanium basket and screw designs in the mandibular completely edentulous application. The hydroxyapatite-coated cylinder and grooved implants in the maxillary posterior partially edentulous application had similar survival rates. The survival of the hydroxyapatite-coated cylinder exceeded that of the titanium basket in mandibular posterior partially edentulous applications. Analyses by phase of treatment indicated a pattern of early failure for nonhydroxyapatite-coated implants compared with hydroxyapatite-coated implants. The implant with the highest survival at all phases of treatment was the hydroxyapatite-coated press-fit cylinder. Two hydroxyapatite-coated implant designs performed well in the challenging posterior maxillary region. PMID:12500876

Morris, H F; Winkler, S; Ochi, S

2001-01-01

80

Dynamic influences of changing gear tooth stiffness  

SciTech Connect

One of the principal sources of vibratory excitation of gear a system is due to the angular speed fluctuation of meshing gears due to non-linearities and profile errors and tooth and supporting bearings flexibility. The transmission error is also influenced by the varying force at the contact point of the meshing gear teeth. The varying contact force itself is influenced by the varying tooth stiffness due to change of orientation of teeth relative to each other, during the contact phase of each pair. This paper presents a simplified single degree of freedom gear system. It is assumed that one member of the gear pair is rigid and flexibility of the gear tooth is attributed only to one section of the gear system. This enables the equation to be simplified to a single degree of freedom system. The resulting non-linear equation is solved iteratively by employing a method which combines piecewise linearization for the stiffness and resulting contact orientation shift due to shaft and tooth flexibility. The contact shift will be referred as the phase shift in this report. The early finding indicates that there are significant differences between the response of the system incorporating three different tooth stiffness, namely, constant tooth stiffness, rectangular wave tooth stiffness and sinusoidal tooth stiffness. The results also implies that any design specification associated with gears has to include gear tooth influences, especially if the excitation is of a major concern. The rectangular stiffness variation which most accurately describes the tooth stiffness gives a response fluctuation, studied in the frequency domain shows that the effective natural frequencies fluctuates between certain upper and lower limits. Thus the paper suggest that any design study should consider these limits.

Morguel, O.K. [Sakarya Univ. (Turkey). Dept. of Mechanical Engineering; Esat, I. [Brunel Univ., Uxbridge (United Kingdom). Dept. of Mechanical Engineering

1997-07-01

81

Implant over implant: An alternative method for solving malpositioned osseointegrated implants at the sinus floor.  

PubMed

An implant was malpositioned and osseointegrated at the maxillary sinus floor with no complications. However, unexpected bone formation over the implant made the implant nonfunctional. Because the patient rejected the removal of the implant, it was left in place while another short implant was placed into the newly formed bone in approximately the same position as the old implant to restore the posterior maxillary tooth. Within 6 months, the new implant over the old asymptomatic implant was functional. Radiographs revealed osseointegration and stable periimplant marginal bone level with no signs of infection or inflammation. PMID:24819533

Man, Yi; Wang, Tianlu; Mo, Anchun; Qu, Yili

2014-10-01

82

Stress analysis in bone tissue around single implants with different diameters and veneering materials: a 3-D finite element study.  

PubMed

The aim of this study was to evaluate the stress distribution on bone tissue with a single prosthesis supported by implants of large and conventional diameter and presenting different veneering materials using the 3-D finite element method. Sixteen models were fabricated to reproduce a bone block with implants, using two diameters (3.75×10 mm and 5.00×10 mm), four different veneering materials (composite resin, acrylic resin, porcelain, and NiCr crown), and two loads (axial (200 N) and oblique (100 N)). For data analysis, the maximum principal stress and von Mises criterion were used. For the axial load, the cortical bone in all models did not exhibit significant differences, and the trabecular bone presented higher tensile stress with reduced implant diameter. For the oblique load, the cortical bone presented a significant increase in tensile stress on the same side as the loading for smaller implant diameters. The trabecular bone showed a similar but more discreet trend. There was no difference in bone tissue with different veneering materials. The veneering material did not influence the stress distribution in the supporting tissues of single implant-supported prostheses. The large-diameter implants improved the transference of occlusal loads to bone tissue and decreased stress mainly under oblique loads. Oblique loading was more detrimental to distribution stresses than axial loading. PMID:24094178

Santiago Junior, Joel Ferreira; Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; de Carvalho, Paulo Sérgio Perri

2013-12-01

83

Evaluation of immediately loaded dental implants bioactivated with platelet-rich plasma placed in the mandibular posterior region: A clinico-radiographic study  

PubMed Central

Background and Objectives: The purpose of the present study was to clinically and radiographically assess the soft and hard tissue changes around the immediately loaded single tooth implants bioactivated with platelet-rich plasma (PRP), placed in the mandibular posterior region. Materials and Methods: A total of 11 patients having single tooth edentulous space in the mandibular posterior region were selected. An endosseous implant was placed after clinical and radiographic examination in each selected site using single stage surgical approach. The patients were followed up at 3, 6, 9, and at 12 months of post implant insertion. The patients were subjected to recording of clinical parameters like modified plaque index, modified gingival index, probing depth, and clinical implant mobility scale. Radiographs made at different intervals were subjected to assessment of bone level mesial and distal to each implant using computer assisted image analysis. Results: Scores for clinical parameters were minimal and comparable. The probing depth around the implant was measured during the follow-up period and the changes observed were statistically non-significant. None of the implants were clinically mobile during the follow-up period. Radiographically, the peri-implant bone resorption both on mesial and distal sides was within normal limit after one year of immediate loading. Finally, the overall success rate for the immediately loaded bioactivated implant placed in the mandibular posterior region was recorded as 100%. Interpretation and Conclusion: The use of platelet-rich plasma may lead to improved early bone apposition around the implant; and thus, results in increased rate of osseointegration. Single stage implant procedure with the adjunctive use of PRP enhances the ability of peri-implant healing tissue to create favorable soft and hard tissue relationships. It also gives the added advantage of psychological boost for the patient by getting fixed replacement of tooth within a short time period. PMID:22628970

Anand, Ullas; Mehta, D. S.

2012-01-01

84

Characterization of the beam transmission improvements for p- and n-LDD implantations on a single wafer high current spot beam implanter  

NASA Astrophysics Data System (ADS)

This paper focuses on the characterization of the biased beam guide option installed in the 200 mm Axcelis Optima HDx single wafer high current spot beam implanter and its use for energy contamination free, drift mode p-LDD and n-LDD implantations. Biased beam guide mode allows reduction of space charge potential and corresponding transmission loss from beam blow up, resulting in horizontally and vertically smaller ion beams. Smaller, highly focused beams have several advantages, such as improved beam transmission, higher dose rate, and require reduced overscan area. Higher beam transmission and higher beam current combined with reduced overscan are two factors that directly affect throughput and productivity. We demonstrate these improvements for several important logic processes. A characterization of the effects of beam guide bias voltage for a 90 nm CMOS logic is reported in detail. The p-LDD and n-LDD implantations investigated were BF2+, As+, and As2+ in the energy range between 3 keV and 5 keV, both with and without Germanium pre-amorphization. The presented and discussed results include beam parameters, throughput results, beam setup performance, and device data. The results have shown that the biased beam guide mode can significantly improve the throughput for the LDD implantations in the energy range of interest.

Schmeide, Matthias; Kondratenko, Serguei; Deichler, Josef

2012-11-01

85

Single dental implant retained mandibular complete dentures - influence of the loading protocol: study protocol for a randomized controlled trial  

PubMed Central

Background Over the years, there has been a strong consensus in dentistry that at least two implants are required to retain a complete mandibular denture. It has been shown in several clinical trials that one single median implant can retain a mandibular overdenture sufficiently well for up to 5 years without implant failures, when delayed loading was used. However, other trials have reported conflicting results with in part considerable failure rates when immediate loading was applied. Therefore it is the purpose of the current randomized clinical trial to test the hypothesis that immediate loading of a single mandibular midline implant with an overdenture will result in a comparable clinical outcome as using the standard protocol of delayed loading. Methods/design This prospective nine-center randomized controlled clinical trial is still ongoing. The final patient will complete the trial in 2016. In total, 180 edentulous patients between 60 and 89 years with sufficient complete dentures will receive one median implant in the edentulous mandible, which will retain the existing complete denture using a ball attachment. Loading of the median implant is either immediately after implant placement (experimental group) or delayed by 3 months of submerged healing at second-stage surgery (control group). Follow-up of patients will be performed for 24 months after implant loading. The primary outcome measure is non-inferiority of implant success rate of the experimental group compared to the control group. The secondary outcome measures encompass clinical, technical and subjective variables. The study was funded by the Deutsche Forschungsgemeinschaft (German research foundation, KE 477/8-1). Discussion This multi-center clinical trial will give information on the ability of a single median implant to retain a complete mandibular denture when immediately loaded. If viable, this treatment option will strongly improve everyday dental practice. Trial registration The trial has been registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00003730 since 23 August 2012. (http://www.germanctr.de). PMID:24884848

2014-01-01

86

Single-blind randomized clinical trial to evaluate clinical and radiological outcomes after one year of immediate versus delayed implant placement supporting full-arch prostheses  

PubMed Central

Purpose: To evaluate and compare peri-implant health, marginal bone loss and success of immediate and delayed implant placement for rehabilitation with full-arch fixed prostheses. Material and Methods: The present study was a prospective, randomized, single-blind, clinical preliminary trial. Patients were randomized into two treatment groups. In Group A implants were placed immediately post-extraction and in Group B six months after extraction. The following control time-points were established: one week, six months and twelve months after loading. Measurements were taken of peri-implant crevicular fluid volume, plaque index, gingival retraction, keratinized mucosa, probing depth, modified gingival index and presence of mucositis. Implant success rates were evaluated for the two groups. The study sample included fifteen patients (nine women and six men) with a mean average age of 63.7 years. One hundred and forty-four implants were placed: 76 placed in healed sites and 68 placed immediately. Results: At the moment of prosthetic loading, keratinized mucosa width and probing depth were higher in immediate implants than delayed implants, with statistically significant differences. However, after six and twelve months, differences between groups had disappeared. Bone loss was 0.54 ± 0.39 mm for immediate implants and 0.66 ± 0.25 mm for delayed implants (p=0.201). No implants failed in either group. Conclusions: The present study with a short follow-up and a small sample yielded no statistically significant differences in implant success and peri-implant marginal bone loss between immediate and delayed implants with fixed full-arch prostheses. Peri-implant health showed no statistically significant differences for any of the studied parameters (crevicular fluid volume, plaque index, gingival retraction, keratinized mucosa, probing depth, modified gingival index and presence of mucositis) at the twelve-month follow-up. Key words:Immediate implants, delayed implants, peri-implant health, success rate. PMID:24316712

Pellicer-Chover, Hilario; Penarrocha-Oltra, David; Bagan, Leticia; Fichy-Fernandez, Antonio J.; Canullo, Luigi

2014-01-01

87

Current challenges in successful rehabilitation with oral implants.  

PubMed

Very high survival/success rates have been reported for implant treatment, irrespective of the prosthetic type of reconstruction, be those full arcs, partial dentures, combined tooth implants or single crowns. However, survival/success is commonly reported in simple Cumulative Survival/Success Rate (CSR) tables only that may overestimate the true clinical outcome; furthermore, future challenges to clinical success may originate from too rapid launching of untested novelties or recommendations to apply too bold clinical procedures, potential problems that are summarised in the present paper. PMID:20969613

Wennerberg, A; Albrektsson, T

2011-04-01

88

Origins of low resistivity and Ge donor level in Ge ion-implanted ZnO bulk single crystals  

SciTech Connect

The energy level of Ge in Ge-ion implanted ZnO single crystals is studied by Hall-effect and photoluminescence (PL) methods. The variations in resistivity from ?10{sup 3} ?cm for un-implanted samples to ?10{sup ?2} ?cm for as-implanted ones are observed. The resistivity is further decreased to ?10{sup ?3} ?cm by annealing. The origins of the low resistivity are attributed to both the zinc interstitial (Zn{sub i}) related defects and the electrical activated Ge donor. An activation energy of Ge donors estimated from the temperature dependence of carrier concentration is 102 meV. In PL studies, the new peak at 372 nm (3.33 eV) related to the Ge donor is observed in 1000 °C annealed samples.

Kamioka, K.; Oga, T.; Izawa, Y.; Kuriyama, K. [College of Engineering and Research Center of Ion Beam Technology, Hosei University Koganei, Tokyo 184-8584 (Japan); Kushida, K. [Departments of Arts and Sciences, Osaka Kyoiku University Kashiwara, Osaka 582-8582 (Japan)

2013-12-04

89

Origins of low resistivity and Ge donor level in Ge ion-implanted ZnO bulk single crystals  

NASA Astrophysics Data System (ADS)

The energy level of Ge in Ge-ion implanted ZnO single crystals is studied by Hall-effect and photoluminescence (PL) methods. The variations in resistivity from ˜103 ?cm for un-implanted samples to ˜10-2 ?cm for as-implanted ones are observed. The resistivity is further decreased to ˜10-3 ?cm by annealing. The origins of the low resistivity are attributed to both the zinc interstitial (Zni) related defects and the electrical activated Ge donor. An activation energy of Ge donors estimated from the temperature dependence of carrier concentration is 102 meV. In PL studies, the new peak at 372 nm (3.33 eV) related to the Ge donor is observed in 1000 °C annealed samples.

Kamioka, K.; Oga, T.; Izawa, Y.; Kuriyama, K.; Kushida, K.

2013-12-01

90

Implantation strategy of the atrial dipole impacts atrial sensing performance of single lead VDD pacemakers.  

PubMed

Intermittent atrial undersensing is observed in a considerable percentage of patients with single lead VDD pacemakers. Analyzing the 2-year data of the Saphir Multicenter Follow-Up Study, the authors investigated predictors for the occurrence of undersensing. The study included 194 patients with high degree AV block who received a VDD pacemaker system with an identical sensing amplifier. Placement strategy of the atrial dipole was left to the discretion of the implanting physician. At the final position, atrial potential amplitudes were measured during deep and shallow respiration. Atrial dipole position was determined by intraoperativefluoroscopy subdividing the right atrium in a high, mid, and low portion. Undersensing was defined by evidence of at least one not sensed P wave during Holter monitoring or exercise testing and by the presence of 0.1-0.2 mV amplitudes in the P wave amplitude histogram of the pacemaker. Incidence of undersensing was 25.8%; 9.3% of patients showed frequent (> 5%) or symptomatic undersensing. Patients with undersensing were older (76.6 +/- 10.6 vs 64.2 +/- 14.8 years), showed a lower minimum of intraoperative atrial potential amplitude (P(min) 0.86 +/- 0.64 vs 1.43 +/- 0.77 mV), a wider range of potential amplitude (deltaP 1.71 +/- 1.44 vs 0.94 +/- 0.84 mV), and a higher incidence of dipole placement in the low right atrium (50.0% vs 11.1 %, P < 0.001 for all comparisons). In a multivariate regression analysis, patient age > 66 years, Pmin < 0.6 mV, > 1.3 mV and atrial dipol placement in the lowright atrium were independently predictive for undersensing. Minimal atrialpotential amplitude, range of potential amplitude, and atrial dipole position influence atrial sensing performance in single lead VDD pacing. Thus, implantation guidelines should reflect these rules to improve the outcome of VDD pacemaker recipients. PMID:11990661

Wiegand, Uwe K H; Nowak, Bernd; Reisp, Udo; Peiffer, Torsten; Bode, Frank; Potratz, Jürgen

2002-03-01

91

Implantable cardioverter defibrillator therapy in pediatric and congenital heart disease patients: a single tertiary center experience in Korea  

PubMed Central

Purpose The use of implantable cardioverter defibrillators (ICDs) to prevent sudden cardiac death is increasing in children and adolescents. This study investigated the use of ICDs in children with congenital heart disease. Methods This retrospective study was conducted on the clinical characteristics and effectiveness of ICD implantation at the department of pediatrics of a single tertiary center between 2007 and 2011. Results Fifteen patients underwent ICD implantation. Their mean age at the time of implantation was 14.5±5.4 years (range, 2 to 22 years). The follow-up duration was 28.9±20.4 months. The cause of ICD implantation was cardiac arrest in 7, sustained ventricular tachycardia in 6, and syncope in 2 patients. The underlying disorders were as follows: ionic channelopathy in 6 patients (long QT type 3 in 4, catecholaminergic polymorphic ventricular tachycardia [CPVT] in 1, and J wave syndrome in 1), cardiomyopathy in 5 patients, and postoperative congenital heart disease in 4 patients. ICD coils were implanted in the pericardial space in 2 children (ages 2 and 6 years). Five patients received appropriate ICD shock therapy, and 2 patients received inappropriate shocks due to supraventricular tachycardia. During follow-up, 2 patients required lead dysfunction-related revision. One patient with CPVT suffered from an ICD storm that was resolved using sympathetic denervation surgery. Conclusion The overall ICD outcome was acceptable in most pediatric patients. Early diagnosis and timely ICD implantation are recommended for preventing sudden death in high-risk children and patients with congenital heart disease. PMID:23559974

Jin, Bo Kyung; Bang, Ji Seok; Choi, Eun Young; Kim, Gi Beom; Kwon, Bo Sang; Noh, Chung Il; Choi, Jung Yun; Kim, Woong Han

2013-01-01

92

How a Tooth Decays  

MedlinePLUS

... 2. White Spots Enamel is the hard outer crystal-like layer. Dentin is the softer layer beneath ... carbohydrates can make acid. The acid attacks the crystal-like substance in the tooth's outer surface. This ...

93

Tooth Colored Fillings  

MedlinePLUS

... Feeling in the dentin is transmitted through the pulp , or nerve tissues , in the very center of the tooth. To mimic the natural dentin in the teeth, today’s dental composite resins are common in non- ...

94

Cracked Tooth Syndrome  

MedlinePLUS

... That's because these teeth absorb most of the forces of chewing. Some people grind or clench their ... Symptoms The tooth may hurt sometimes when you bite or chew. The sensitivity or pain can be ...

95

Tooth in oropharynx.  

PubMed

The incidence of ectopic teeth has increased. In many cases, the etiology of ectopic teeth cannot be identified. Ectopic tooth in deciduous dentition period is very rare and information is limited about its causes and characteristics. The conditions commonly associated with an increased prevalence of ectopic teeth include cleft lip and palate, cleidocranial dysplasia, and Gardner syndrome. The diagnosis is made by the clinical and radiological examinations. The indication for extraction in ectopic teeth cases is in general determined by the presence of symptomatology, or by the need for preventing future complications. We present a case of an ectopic maxillary tooth in a 4 year-old boy. In addition, this report also addresses a young patient with a tooth in the oropharynx with the objective of non traumatic etiology, and such a clinical presentation is extremely rare. The authors believe the case presented here is the first documented case of an ectopic supernumerary tooth seen in the oropharynx. PMID:22144844

Nagarajappa, D; Manjunatha, Bs

2011-09-01

96

A new etching method for single-crystal Al 2O 3 film on Si using Si ion implantation  

Microsoft Academic Search

A new etching method for a single-crystalline Al2O3 (100) film grown on Si (100) by chemical-vapour deposition (CVD) and a sapphire wafer is proposed for the first time using Si ion implantation and HF chemical etchant to develop potential applications of the silicon on insulator (SOI) structure. Line and space patterns of resist are transferred to sharp Al2O3 and Si

Makoto Ishida; Hoon Kim; Takayuki Kimura; Tetsuro Nakamura

1996-01-01

97

Surface characterization of Cu-ion implanted single crystal and thin film ZnO for catalytic applications  

Microsoft Academic Search

Single crystals and thin films of zinc oxide were implanted with copper ions in order to study the catalytic properties of a mixed Cu-ZnO system. ZnO is widely used as a catalyst in the methanol synthesis reaction, and copper has been noted to have a synergistic effect on the rates and yields of reaction. The samples were characterized by x-ray

J. S. Brodkin; D. Chadwick

1995-01-01

98

Effect of cyclic load on vertical misfit of prefabricated and cast implant single abutment  

PubMed Central

Objective The purpose of this in vitro study was to evaluate misfit alterations at the implant/abutment interface of external and internal connection implant systems when subjected to cyclic loading. Material and Methods Standard metal crowns were fabricated for 5 groups (n=10) of implant/abutment assemblies: Group 1, external hexagon implant and UCLA cast-on premachined abutment; Group 2, internal hexagon implant and premachined abutment; Group 3, internal octagon implant and prefabricated abutment; Group 4, external hexagon implant and UCLA cast-on premachined abutment; and Group 5, external hexagon implant and Ceraone abutment. For groups 1, 2, 3 and 5, the crowns were cemented on the abutments and in group 4 crowns were screwed directly on the implant. The specimens were subjected to 500,000 cycles at 19.1 Hz of frequency and non-axial load of 133 N in a MTS 810 machine. The vertical misfit (?m) at the implant/abutment interface was evaluated before (B) and after (A) application of the cyclic loading. Data were analyzed statistically by using two-away ANOVA and Tukey’s post-hoc test (p<0.05). Results Before loading values showed no difference among groups 2 (4.33±3.13), 3 (4.79±3.43) and 5 (3.86±4.60); between groups 1 (12.88±6.43) and 4 (9.67±3.08), and among groups 2, 3 and 4. However, groups 1 and 4 were significantly different from groups 2, 3 and 5. After loading values of groups 1 (17.28±8.77) and 4 (17.78±10.99) were significantly different from those of groups 2 (4.83±4.50), 3 (8.07±4.31) and 5 (3.81±4.84). There was a significant increase in misfit values of groups 1, 3 and 4 after cyclic loading, but not for groups 2 and 5. Conclusion The cyclic loading and type of implant/abutment connection may develop a role on the vertical misfit at the implant/abutment interface. PMID:21437464

DE JESUS TAVAREZ, Rudys Rodolfo; BONACHELA, Wellington Cardoso; XIBLE, Anuar Antônio

2011-01-01

99

Nanomechanical characterization of cavity growth and rupture in hydrogen-implanted single-crystal BaTiO3  

NASA Astrophysics Data System (ADS)

A thermodynamic model of cavity nucleation and growth in ion-implanted single-crystal BaTiO3 layer is proposed, and cavity formation is related to the measured mechanical properties to better understand hydrogen implantation-induced layer transfer processes for ferroelectric thin films. The critical radius for cavity nucleation was determined experimentally from blistering experiments performed under isochronal anneal conditions and was calculated using continuum mechanical models for deformation and fracture, together with thermodynamic models. Based on thermodynamic modeling, we suggest that cavities grow toward the cracking criteria at a critical blister size whereupon gas is emitted from ruptured cavities. The main driving force for layer splitting is the reduction of the overall elastic energy stored in the implanted region during the cavity nucleation and growth as the gaseous H2 entrapped within the cavities is released. Nanoindentation measurements reveal locally the mechanical property changes within the vicinity of a single cavity. Using the measured mechanical properties at the single-cavity level, we developed three-dimensional strain and stress profiles using finite element method.

Park, Young-Bae; Nardi, Patrick; Li, Xiaodong; Atwater, Harry A.

2005-04-01

100

Bone Substitutes for Peri-Implant Defects of Postextraction Implants  

PubMed Central

Placement of implants in fresh sockets is an alternative to try to reduce physiological resorption of alveolar ridge after tooth extraction. This surgery can be used to preserve the bone architecture and also accelerate the restorative procedure. However, the diastasis observed between bone and implant may influence osseointegration. So, autogenous bone graft and/or biomaterials have been used to fill this gap. Considering the importance of bone repair for treatment with implants placed immediately after tooth extraction, this study aimed to present a literature review about biomaterials surrounding immediate dental implants. The search included 56 articles published from 1969 to 2012. The results were based on data analysis and discussion. It was observed that implant fixation immediately after extraction is a reliable alternative to reduce the treatment length of prosthetic restoration. In general, the biomaterial should be used to increase bone/implant contact and enhance osseointegration. PMID:24454377

Santos, Pamela Leticia; Gulinelli, Jessica Lemos; Telles, Cristino da Silva; Betoni Junior, Walter; Chiacchio Buchignani, Vivian; Queiroz, Thallita Pereira

2013-01-01

101

Photoluminescence of Au - formed in 12CaO · 7Al 2O 3 single crystal by Au +-implantation  

NASA Astrophysics Data System (ADS)

Au + ion implantation with fluences from 1 × 10 14 to 3 × 10 16 cm -2 into 12CaO · 7Al 2O 3 (C12A7) single crystals was carried out at a sample temperature of 600 °C. The implanted sample with the fluence of 1 × 10 15 cm -2 exhibited photoluminescence (PL) bands peaking at ˜3.1 and ˜2.3 eV at ?150 K when excited by He-Cd laser (325 nm). This was the first observation of PL from C12A7. These two PL bands are possibly due to intra-ionic transitions of an Au - ion having the electronic configuration of 6 s2, judged from their similarities to those reported on Au - ions in alkali halides. However, when the concentration of the implanted Au ions exceeded the theoretical maximum value of anions encaged in C12A7 (˜2.3 × 10 21 cm -3), surface plasmon absorption appeared in the optical absorption spectrum, suggesting Au colloids were formed at such high fluences. These observations indicate that negative gold ions are formed in the cages of C12A7 by the Au + implantation if an appropriate fluence is chosen.

Miyakawa, M.; Kamioka, H.; Hirano, M.; Kamiya, T.; Hosono, H.

2006-09-01

102

Advanced predoctoral implant program at UIC: description and qualitative analysis.  

PubMed

Dental implant education has increasingly become an integral part of predoctoral dental curricula. However, the majority of implant education emphasizes the restorative aspect as opposed to the surgical. The University of Illinois at Chicago College of Dentistry has developed an Advanced Predoctoral Implant Program (APIP) that provides a select group of students the opportunity to place implants for single-tooth restorations and mandibular overdentures. This article describes the rationale, logistics, experiences, and perspectives of an innovative approach to provide additional learning experiences in the care of patients with partial and complete edentulism using implant-supported therapies. Student and faculty perspectives on the APIP were ascertained via focus group discussions and a student survey. The qualitative analysis of this study suggests that the select predoctoral dental students highly benefited from this experience and intend to increase their knowledge and skills in implant dentistry through formal education following graduation. Furthermore, the survey indicates that the APIP has had a positive influence on the students' interest in surgically placing implants in their future dental practice and their confidence level in restoring and surgically placing implants. PMID:24789837

Afshari, Fatemeh S; Yuan, Judy Chia-Chun; Quimby, Anastasiya; Harlow, Rand; Campbell, Stephen D; Sukotjo, Cortino

2014-05-01

103

Implant-Supported Bridge  

MedlinePLUS

... can be built up using bone augmentation or grafting before the actual implant procedure begins. How Does It Work? In some cases, ... the space created by the missing tooth. Second procedure Month 4 or 5 (no bone grafting, lower jaw) Month 6 or 7 (no bone ...

104

Functional tooth regenerative therapy: tooth tissue regeneration and whole-tooth replacement.  

PubMed

Oral and general health is compromised by irreversible dental problems, including dental caries, periodontal disease and tooth injury. Regenerative therapy for tooth tissue repair and whole-tooth replacement is currently considered a novel therapeutic concept with the potential for the full recovery of tooth function. Several types of stem cells and cell-activating cytokines have been identified in oral tissues. These cells are thought to be candidate cell sources for tooth tissue regenerative therapies because they have the ability to differentiate into tooth tissues in vitro and in vivo. Whole-tooth replacement therapy is regarded as an important model for the development of an organ regenerative concept. A novel three-dimensional cell-manipulation method, designated the organ germ method, has been developed to recapitulate organogenesis. This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions. A bioengineered tooth germ can generate a structurally correct tooth in vitro and erupt successfully with the correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was successfully engrafted into an adult jawbone through bone integration. Such bioengineered teeth were able to perform normal physiological tooth functions, such as developing a masticatory potential in response to mechanical stress and a perceptive potential for noxious stimuli. In this review, we describe recent findings and technologies underpinning tooth regenerative therapy. PMID:25052182

Oshima, Masamitsu; Tsuji, Takashi

2014-07-01

105

A technique to salvage endodontically compromised maxillary anterior tooth.  

PubMed

A complication of endodontic treatment is over-preparation of the tooth structure in an attempt to access calcified pulp chambers and root canals. This could result in thin root walls that might compromise the long-term prognosis of the tooth. There are various treatment options when such a complication occurs, among them, extraction of the compromised tooth and its replacement with a dental implant. This clinical report describes a nonsurgical, multidisciplinary treatment alternative where a maxillary anterior tooth with a thinned root wall was successfully saved by repairing the damaged root to its original thickness using a composite resin material and subsequently restoring with a cast post and core and a crown. PMID:24654367

Comut, Alper; Foran, Denise; Cunningham, Ralph P

2014-01-01

106

[Indications for oral implantology in a referral clinic. A three-year retrospective analysis of 737 patients with 1176 implants].  

PubMed

The following study reviews patients from the Department of Oral Surgery and Stomatology at the University of Berne undergoing implant therapy. Between 2000 and 2002, 737 patients received 1176 ITI screw-type implants. At least 70% of these patients were 50 years or older. The main reason for tooth loss in this group was often periodontitis, followed by carious, periapical infection and root fractures. Only 15% of the patients were younger than 30 years. They had lost their teeth mainly due to trauma or agenesis of teeth. This study reports a trend towards treatment of partially edentulous patients (>90%), with single tooth gaps (>50%) being the most frequent indication for implant therapy. The analysis also demonstrated the importance of augmentation procedures prior to implant placement. Almost 40% of the implant cases required either ridge augmentation or sinus lift procedures. The GBR technique was frequently utilized in the anterior maxilla, especially with bone defects resulting from dental trauma. Data also showed that with these augmentation procedures more implants were inserted in the maxilla (53%) than in the mandible. During the healing or early loading phase only six implants out of 1176 were lost, resulting in an early failure rate of 0.51%. Our study has demonstrated that a high level of implant success can be achieved with the ITI system when using a strict selection criteria and stringent operating protocols. PMID:15250175

Sulzer, Thomas H; Bornstein, Michael M; Buser, Daniel

2004-01-01

107

Morphological Features of Peri-Implant Tissue after Placement of Dental Implants into the Extraction Socket  

Microsoft Academic Search

In experiments on pigs, bone regeneration was studied after implantation of implants with four cylindrical roots and support\\u000a cone and laminar crest-shaped implants with shape memory effect. The implants were placed to the extraction socket (mandibular\\u000a canine) and through the socket immediately after tooth extraction using osteoplastic material or without using collapan-L.\\u000a The use of collapan-L accelerated regeneration of peri-implant

M. V. Kotenko; L. L. Meysner

108

Treatment of a patient with cleidocranial dysplasia using a single-stage implant protocol.  

PubMed

This patient report describes the treatment of a 45-year-old Caucasian woman with cleidocranial dysplasia who had significant dental problems that greatly affected her quality of life. The patient had orthodontic treatment in her earlier years along with surgical removal of supernumerary teeth. Using implants, the maxillary and mandibular arches were restored with fixed screw-retained prostheses. Eight implants and six implants were placed in the maxilla and mandible, respectively. Both arches were immediately loaded following the Teeth in a Day™ protocol using an all-acrylic resin provisional prosthesis. Five months later, definitive maxillary and mandibular prostheses were fabricated. The patient has been followed for a period of 5 years, and all postoperative evaluations have been uneventful. PMID:22003879

Petropoulos, Vicki C; Balshi, Thomas J; Wolfinger, Glenn J; Balshi, Stephen F

2011-10-01

109

Vital tooth whitening.  

PubMed

Vital tooth whitening, when administered correctly, is by all accounts one of the safest, most conservative, least expensive, and most effective aesthetic procedures currently available to patients. This article traces the evolution of the technology, describes what is known about the mechanism of action and explores such issues as toxicology and side effects associated with tooth whitening. The article also describes the various tooth-whitening systems, which include dentist-supervised night-guard bleaching, in-office or power bleaching, and bleaching with over-the-counter bleaching products. Combination treatments and light-activated treatments are also discussed. Finally, the article summarizes the areas of research needed in this field. PMID:17532915

Kihn, Patricia W

2007-04-01

110

Immediate bone augmentation after infected tooth extraction using titanium membranes.  

PubMed

Infectious process frequently results in extensive bone resorption and defect, periradicular or periapical lesions, or vertical fracture with infected sinus tract. When tooth extraction is mandated it typically results in additional bone loss in the buccal or lingual cortical plate. Immediate guided bone regeneration (GBR) and implant fixation at an infected site is frequently complicated by soft-tissue dehiscence, membrane exposure, and implant failure. The objective of this research is to assess the feasibility of immediate bone augmentation (IBA) after purulent tooth extraction, employing a dedicated titanium membrane. An intrasulcular incision was made around the tooth to be extracted and extended to 2 adjacent teeth while maintaining the papillae. Vertical releasing incisions were made to mobilize the mucoperiosteal flap. Cautious tooth extraction was executed utilizing conventional measures and was followed by meticulous curettage of the infected and granulated tissue in the socket. Titanium membranes were applied to the socket walls followed by socket filling with autologous platelet-rich fibrin and primary closure. Eight or more weeks later membrane removal and implant placement were performed. Of the 15 patients who underwent this procedure, 7 patients (47%) had early membrane exposure (between weeks 2 and 6), which was treated conservatively. No infection or early membrane removal was reported. All patients achieved sufficient bone augmentation, and 8 patients received implants without any additional GBR. IBA after infected tooth extraction, using titanium membrane application was feasible and safe and yielded adequate bone filling to support implant fixation at > or =8 weeks. Further studies need to evaluate if the titanium membrane helped in any way to inhibit plaque accumulation or resist infection in cases of early membrane exposure. PMID:17674679

Kfir, Efraim; Kfir, Vered; Kaluski, Edo

2007-01-01

111

Photoluminescence from Au ion-implanted nanoporous single-crystal 12CaO•7Al2O3  

NASA Astrophysics Data System (ADS)

Implantation of Au+ ions into a single crystalline 12CaO•7Al2O3 (C12A7) was performed at high temperatures with fluences from 1×1014 to 3×1016cm-2 . This material is composed of positively charged sub-nanometer-sized cages compensated by extra-framework negatively charged species. The depth profile of concentrations of Au species was analyzed using Rutherford backscattering spectrometry. The measured optical spectra and ab initio embedded cluster calculations show that the implanted Au species are stabilized in the form of negative Au- ions below the fluences of ˜1×1016cm-2 (Au volume concentration of ˜2×1021cm-3 ). These ions are trapped in the cages and exhibit photoluminescence (PL) bands peaking at 3.05 and 2.34eV at temperatures below 150K . At fluences exceeding ˜3×1016cm-2 , the implanted Au atoms form nano-sized clusters. This is manifested in quenching of the PL bands and creation of an optical absorption band at 2.43eV due to the surface plasmon of free carriers in the cluster. The PL bands are attributed to the charge transfer transitions (Au0+e-?Au-) due to recombination of photo-excited electrons (e-) , transiently transferred by ultraviolet excitation into a nearby cages, with Au0 atoms.

Miyakawa, Masashi; Kamioka, Hayato; Hirano, Masahiro; Kamiya, Toshio; Sushko, Peter V.; Shluger, Alexander L.; Matsunami, Noriaki; Hosono, Hideo

2006-05-01

112

The Tooth, the Whole Tooth and Nothing But the Tooth: How Belief in the Tooth Fairy Can Engender False Memoriesy  

Microsoft Academic Search

SUMMARY To examine how children's fantasy beliefs can affect memory for their experiences, 5- and 6-year-olds with differing levels of belief in the reality of the Tooth Fairy were prompted to recall their most recent primary tooth loss in either a truthful or fun manner. Many of the children who fully believed in the existence of the Tooth Fairy reported

GABRIELLE F. PRINCIPE; ERIC SMITH

113

What Are Tooth Preservation Kits?  

MedlinePLUS

... kits — what are they and should all parents have one? - Cara Active kids do run the risk of losing a tooth ... permanent tooth, it's a dental emergency. Permanent teeth have the best chance of ... immediately . For older kids and teens, try placing the tooth back in ...

114

LVAD Implant as a Bridge to Heart Transplantation is Associated with Allosensitization as Measured by Single Antigen Bead Assay  

PubMed Central

Background Left ventricular assist devices (LVAD) as a bridge (BTT) to heart transplantation (HTX) may be limited by the formation of anti-HLA antibodies. Whether sensitization occurs with continuous axial flow LVAD implant as assessed by Single Antigen Bead (SAB) assay is unknown. Methods Cytotoxic panel reactive antibody (PRA) and SAB assays were analyzed in HTX recipients undergoing LVAD implant as a BTT. Sensitization was defined as peak anti-HLA antibody values of >2000 mean fluorescent intensity as these values have been found to correlate with flow cytometric crossmatch results. Results LVADs were implanted as BTT in 30 patients. There were 7% (2/30) of patients prior to and no patients after LVAD implant with PRA >10%. However, 20% (6/30) of patients prior to and 53% (16/30) after LVAD were sensitized as measured by SAB (p=0.024). At HTX, 47% (14/30) of patients remained sensitized. A positive virtual crossmatch was observed in 28% (4/14) of the sensitized patients at HTX. There was no difference between the sensitized and non-sensitized groups (p>0.4 for all) in usage of blood products (64 11 vs. 63 39 units), time to HTX (286 63 vs. 257 48 days) and 1 year after HTX, there were no differences in rejection (total rejection score 0.30 vs. 0.37) and survival (93% vs. 88%). Conclusion Allosensitization after LVAD is common despite cytotoxic PRA being negative. One year after HTX, this sensitization does not translate into increased acute cellular or antibody mediated rejection or reduced survival. PMID:23743727

Shankar, Nisha; Daly, Richard; Geske, Jennifer; Kushwaha, Sudhir K; Timmons, Michael; Joyce, Lyle; Stulak, John; Gandhi, Manish; Kremers, Walter; Park, Soon; Pereira, Naveen L

2013-01-01

115

Immediate and early replacement implants and restorations.  

PubMed

There have been rapid developments in dental implant treatment protocols to reduce the time between implant placement and restoration. Implants may be placed immediately following tooth extraction or following a period of healing to allow resolution of residual infection or sufficient bone and soft tissue healing. Early restoration and loading of implants has to be carefully controlled to avoid increased failure and complications. Advantages and disadvantages of the various techniques are described. PMID:18561804

Palmer, R M; Palmer, P J; Baker, P

2008-03-01

116

The rachitic tooth.  

PubMed

Teeth are mineralized organs composed of three unique hard tissues, enamel, dentin, and cementum, and supported by the surrounding alveolar bone. Although odontogenesis differs from osteogenesis in several respects, tooth mineralization is susceptible to similar developmental failures as bone. Here we discuss conditions fitting under the umbrella of rickets, which traditionally referred to skeletal disease associated with vitamin D deficiency but has been more recently expanded to include newly identified factors involved in endocrine regulation of vitamin D, phosphate, and calcium, including phosphate-regulating endopeptidase homolog, X-linked, fibroblast growth factor 23, and dentin matrix protein 1. Systemic mineral metabolism intersects with local regulation of mineralization, and factors including tissue nonspecific alkaline phosphatase are necessary for proper mineralization, where rickets can result from loss of activity of tissue nonspecific alkaline phosphatase. Individuals suffering from rickets often bear the additional burden of a defective dentition, and transgenic mouse models have aided in understanding the nature and mechanisms involved in tooth defects, which may or may not parallel rachitic bone defects. This report reviews dental effects of the range of rachitic disorders, including discussion of etiologies of hereditary forms of rickets, a survey of resulting bone and tooth mineralization disorders, and a discussion of mechanisms, known and hypothesized, involved in the observed dental pathologies. Descriptions of human pathology are augmented by analysis of transgenic mouse models, and new interpretations are brought to bear on questions of how teeth are affected under conditions of rickets. In short, the rachitic tooth will be revealed. PMID:23939820

Foster, Brian L; Nociti, Francisco H; Somerman, Martha J

2014-02-01

117

Charcot Marie Tooth Disease  

Microsoft Academic Search

Charcot Marie Tooth (CMT) disease was first described in 1886. It describes a spectrum of genetic disorders that affects peripheral nerves, either by slowing action potential transmission along the axons, or by reducing the amplitude, or both.It is this variety of underlying genetic findings and subtleties of clinical presentation that has resulted in the varying nomenclature over the years. Patients

D. W. J. Howcroft; S. Kumar; N. Makwana

2009-01-01

118

Current trends in dental implants  

PubMed Central

Tooth loss is very a very common problem; therefore, the use of dental implants is also a common practice. Although research on dental implant designs, materials and techniques has increased in the past few years and is expected to expand in the future, there is still a lot of work involved in the use of better biomaterials, implant design, surface modification and functionalization of surfaces to improve the long-term outcomes of the treatment. This paper provides a brief history and evolution of dental implants. It also describes the types of implants that have been developed, and the parameters that are presently used in the design of dental implants. Finally, it describes the trends that are employed to improve dental implant surfaces, and current technologies used for the analysis and design of the implants. PMID:24868501

Gaviria, Laura; Salcido, John Paul; Guda, Teja

2014-01-01

119

Revisiting Triple Antibiotic Irrigation of Breast Implant Pockets: A Placebo-controlled Single Practice Cohort Study  

PubMed Central

Background: Capsular contracture is the most common complication following primary augmentation mammoplasty. It remains poorly understood but is attributed to subclinical infection, immunologic response to breast implants, and chronic inflammatory changes caused by the presence of the implants. The infectious theory of contracture has lead to the practice of irrigating implant pockets with a triple antibiotic solution. The purpose of this study was to determine if antibiotic irrigation reduced the incidence and severity of capsular contracture compared with saline irrigation. Methods: A cohort study enrolling all patients having undergone primary augmentation mammoplasty performed by surgeon A and surgeon B between 2011 and 2012 for all women satisfying inclusion and exclusion criteria was conducted. The only difference in surgical technique was the use of antibiotic irrigation by surgeon B. A chi-square test and analysis of variance with predetermined 95% confidence intervals were performed. Results: Fifty-five patients were operated on. Twenty-eight of surgeon A’s patients were included, ranging in age from 22 to 50 with a mean follow-up time of 1.8 years. Twenty-seven of surgeon B’s patients were included, ranging in age from 22 to 56 with a mean follow-up time of 1.6 years. Rate of capsular contracture was 3.6% (surgeon A) and 3.7% (surgeon B). Chi-square statistic was found to be 0.0014 (P = 0.97) and analysis of variance F value was 1 (P = 0.39). Conclusions: Triple antibiotic breast irrigation is not associated with a significant reduction in the incidence or severity of capsular contracture compared with sterile saline when high-quality surgical technique is used.

Bergman, Ronald S.; Folkers, Bryan L.; Kortes, Matthew J.

2013-01-01

120

Three tooth kinematic coupling  

DOEpatents

A three tooth kinematic coupling based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

Hale, Layton C. (Livermore, CA)

2000-01-01

121

Effect of Abutment Height on Retention of Single Cement-retained, Wide- and Narrow-platform Implant-supported Restorations  

PubMed Central

Background and aims In contrast to prepared natural dentin abutments,little is known concerning factors influencing the retention of fixed prostheses cemented to implant abutments. The aim of this study was to investigate the effect of im-plant abutment height on the retention of single castings cemented to wide and narrow platform implant abutments. Materials and methods Thirty-six parallel-sided abutments (Biohorizon Straight Abutment) of narrow platform (NP) and wide platform (WP) sizes with their analogs were used. In each group of platform size, abutments were prepared with axial wall heights of 5, 4, 3, 2 mm (n=9). On the whole 72 castings were constructed, which incorporated an attachment to allow removal. Castings were cemented to abutments with TempBond®. A uniaxial tensile force was applied to the crown using an Instron machine until cement failure occurred. Analysis of variance of the models were fit to determine the effect of height of abutment of the restorations on the mean tensile strength (?=0.05). Results The mean peak removal force for corresponding abutments was significantly different (P < 0.05): (1) with plat-form sizes: WP > NP; (2) with alteration of axial wall height for NP: 5 mm > 4 mm > 3 mm = 2 mm and for WP: 5 mm > 4 mm = 3 mm = 2 mm. Conclusion The retention of NP cement-retained restorations is influenced by the wall height but not in same manner as WP. Restorations of narrow-platform size with longer abutment exhibited higher tensile resistance to dislodgement. PMID:22991646

Saleh Saber, Fariba; Abolfazli, Nader; Nuroloyuni, Sara; Khodabakhsh, Sohleh; Bahrami, Mehran; Nahidi, Reza; Zeighami, Somaieh

2012-01-01

122

Two stage gear tooth dynamics program  

NASA Technical Reports Server (NTRS)

The epicyclic gear dynamics program was expanded to add the option of evaluating the tooth pair dynamics for two epicyclic gear stages with peripheral components. This was a practical extension to the program as multiple gear stages are often used for speed reduction, space, weight, and/or auxiliary units. The option was developed for either stage to be a basic planetary, star, single external-external mesh, or single external-internal mesh. The two stage system allows for modeling of the peripherals with an input mass and shaft, an output mass and shaft, and a connecting shaft. Execution of the initial test case indicated an instability in the solution with the tooth paid loads growing to excessive magnitudes. A procedure to trace the instability is recommended as well as a method of reducing the program's computation time by reducing the number of boundary condition iterations.

Boyd, Linda S.

1989-01-01

123

Comparative stress analysis of delayed and immediate loading of a single implant in an edentulous maxilla model  

PubMed Central

Stress distribution in peri-implant bone in an edentulous maxilla following delayed and immediate loading implant and the effect of implant length on the maximum stress were evaluated by using two kinds of finite element analyses. A threaded implant was loaded with a 100 N vertical force, either immediately or delayed, and examined by finite element analysis with a simple contact relation or a bonding interaction between the implant and the bone, respectively. Higher stresses were observed in cortical bone around the implant neck following delayed loading and in the trabecular bone around the implant threading in the immediate loading model. The maximum stress in the immediate loading model was dramatically higher than in delayed loading. Increased implant length caused decrease in bone stresses in both loading models. Though the stress level was higher, the decrease in the maximum trabecular bone stress in immediate loading was profound. PMID:25342982

Gao, Jie; Esaki, Daisuke; Matsuzaki, Tatsuya; Koyano, Kiyoshi

2014-01-01

124

Comparison of Success of Implants versus Endodontically Treated Teeth  

Microsoft Academic Search

Implants verses root canal therapy is a current controversy in dentistry. The purpose of this investigation was to compare the success of each treatment, with minimal subjective grading. Outcome was determined by clinical chart notes and radiographs. Failure was defined as removal of the implant or tooth. Uncertain findings for implants were defined as mobility class I or greater, radiographic

James Porter Hannahan; Paul Duncan Eleazer

2008-01-01

125

The management of an endodontically abscessed tooth: patient health state utility, decision-tree and economic analysis  

PubMed Central

Background A frequent encounter in clinical practice is the middle-aged adult patient complaining of a toothache caused by the spread of a carious infection into the tooth's endodontic complex. Decisions about the range of treatment options (conventional crown with a post and core technique (CC), a single tooth implant (STI), a conventional dental bridge (CDB), and a partial removable denture (RPD)) have to balance the prognosis, utility and cost. Little is know about the utility patients attach to the different treatment options for an endontically abscessed mandibular molar and maxillary incisor. We measured patients' dental-health-state utilities and ranking preferences of the treatment options for these dental problems. Methods Forty school teachers ranked their preferences for conventional crown with a post and core technique, a single tooth implant, a conventional dental bridge, and a partial removable denture using a standard gamble and willingness to pay. Data previously reported on treatment prognosis and direct "out-of-pocket" costs were used in a decision-tree and economic analysis Results The Standard Gamble utilities for the restoration of a mandibular 1st molar with either the conventional crown (CC), single-tooth-implant (STI), conventional dental bridge (CDB) or removable-partial-denture (RPD) were 74.47 [± 6.91], 78.60 [± 5.19], 76.22 [± 5.78], 64.80 [± 8.1] respectively (p < 0.05). Their respective Willingness-to-Pay ($CDN) were 1,782.05 [± 361.42], 1,871.79 [± 349.44], 1,605.13 [± 348.10], 1,351.28 [± 368.62] (p < 0.05). The standard gamble utilities for the restoration of a maxillary central incisor with a CC, STI, CDB and RPD were 88.50 [± 6.12], 90.68 [± 3.41], 89.78 [± 3.81] and 91.10 [± 3.57] respectively (p > 0.05). Their respective willingness-to-pay ($CDN) were: 1,782.05 [± 361.42], 1,871.79 [± 349.44], 1,605.13 [± 348.10] and 1,351.28 [± 368.62]. A statistical difference was found between the utility of treating a maxillary central incisor and mandibular 1st-molar (p < 0.05). The expected-utility-value for a 5-year prosthetic survival was highest for the CDB and the STI treatment of an abscessed mandibular molar (74.75 and 71.47 respectively) and maxillary incisor (86.24 and 84.91 respectively). This held up to a sensitivity analysis when the success of root canal therapy and the risk of damage to the adjacent tooth were varied. The RPD for both the molar and incisor was the favored treatment based on a cost-utility (3.85 and 2.74 CND$ per year of tooth saved respectively) and cost-benefit analysis (0.92 to 0.60 CND$ of cost per $ of benefit, respectively) for a prosthetic clinical survival of 5-years. Conclusion The position of the abscessed tooth and the amount of insurance coverage influences the utility and rank assigned by patients to the different treatment options. STI and CDB have optimal EUVs for a 5-year survival outcome, and RPD has significantly lower cost providing the better cost:benefit ratio. PMID:18053267

Balevi, Ben; Shepperd, Sasha

2007-01-01

126

Effect of bone density on the damping behavior of dental implants: An in vitro method  

Microsoft Academic Search

For normal healthy teeth the percussive energy generated by mastication is attenuated by the periodontal ligament at the healthy bone–natural tooth interface. However when the natural tooth must be replaced by an implant due to damage or disease the ligament is lost and the implant will transmit the percussive forces directly into the bone. Studies have been carried out to

Lindsey R. VanSchoiack; Jean C. Wu; Cherilyn G. Sheets; James C. Earthman

2006-01-01

127

Smoking and dental implants  

PubMed Central

Smoking is a prevalent behaviour in the population. The aim of this review is to bring to light the effects of smoking on dental implants. These facts will assist dental professionals when implants are planned in tobacco users. A search of “PubMed” was made with the key words “dental implant,” “nicotine,” “smoking,” “tobacco,” and “osseointegration.” Also, publications on tobacco control by the Government of India were considered. For review, only those articles published from 1988 onward in English language were selected. Smoking has its influence on general as well as oral health of an individual. Tobacco negatively affects the outcome of almost all therapeutic procedures performed in the oral cavity. The failure rate of implant osseointegration is considerably higher among smokers, and maintenance of oral hygiene around the implants and the risk of peri-implantitis are adversely affected by smoking. To increase implant survival in smokers, various protocols have been recommended. Although osseointegrated dental implants have become the state of the art for tooth replacement, they are not without limitations or complications. In this litigious era, it is extremely important that the practitioner clearly understands and is able and willing to convey the spectrum of possible complications and their frequency to the patients. PMID:24478965

Kasat, V.; Ladda, R.

2012-01-01

128

Methods for implantation of micro-wire bundles and optimization of single/multi-unit recordings from human mesial temporal lobe  

NASA Astrophysics Data System (ADS)

Objective. The authors report methods developed for the implantation of micro-wire bundles into mesial temporal lobe structures and subsequent single neuron recording in epileptic patients undergoing in-patient diagnostic monitoring. This is done with the intention of lowering the perceived barriers to routine single neuron recording from deep brain structures in the clinical setting. Approach. Over a 15 month period, 11 patients were implanted with platinum micro-wire bundles into mesial temporal structures. Protocols were developed for (A) monitoring electrode integrity through impedance testing, (B) ensuring continuous 24-7 recording, (C) localizing micro-wire position and ‘splay’ pattern and (D) monitoring grounding and referencing to maintain the quality of recordings. Main results. Five common modes of failure were identified: (1) broken micro-wires from acute tensile force, (2) broken micro-wires from cyclic fatigue at stress points, (3) poor in vivo micro-electrode separation, (4) motion artifact and (5) deteriorating ground connection and subsequent drop in common mode noise rejection. Single neurons have been observed up to 14 days post-implantation and on 40% of micro-wires. Significance. Long-term success requires detailed review of each implant by both the clinical and research teams to identify failure modes, and appropriate refinement of techniques while moving forward. This approach leads to reliable unit recordings without prolonging operative times, which will help increase the availability and clinical viability of human single neuron data.

Misra, A.; Burke, J. F.; Ramayya, A. G.; Jacobs, J.; Sperling, M. R.; Moxon, K. A.; Kahana, M. J.; Evans, J. J.; Sharan, A. D.

2014-04-01

129

Tooth portion profile in criminology  

Microsoft Academic Search

Up to date the mineralized tissue is the only option, in many extreme forensic conditions, to achieve a genetic profile. In several samples, both tooth type and portion were studied in order to optimize the methodology and to reduce time and costs.Results from a wisdom tooth (a natural degraded sample), a case of the National Institute Legal Medicine of Portugal,

A. Corte-Real; A. Serra; M. J. Anjos; M. Carvalho; J. Gamero; D. N. Vieira

130

Inter and intra-tooth variation in the oxygen isotope composition of mammalian tooth enamel phosphate: implications for palaeoclimatological and palaeobiological research  

Microsoft Academic Search

Significant differences in the ?18Op value between teeth, and even within a single tooth were observed in a detailed study of the oxygen isotope composition of tooth enamel phosphate (?18Op) of hypsodont teeth from bison and sheep jaws. The permanent molars and premolars of a fossil adult bison from eastern Wyoming (?500 yr B.P.) and a modern sheep from California

Henry C. Fricke; James R. O'Neil

1996-01-01

131

Partial tooth gear bearings  

NASA Technical Reports Server (NTRS)

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Vranish, John M. (Inventor)

2010-01-01

132

Dental Implant Systems  

PubMed Central

Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. PMID:20480036

Oshida, Yoshiki; Tuna, Elif B.; Aktoren, Oya; Gencay, Koray

2010-01-01

133

Using a fiber-reinforced composite fixed partial denture to restore a missing posterior tooth: a case report.  

PubMed

With the advent of new adhesive technologies, fiber-reinforced composite fixed partial dentures (FRC-FPDs) have become an inexpensive, esthetic and useful restorative option for patients missing a single tooth. This article describes a case involving an inlay-retained FRC-FPD with a prefabricated fiber-reinforced pontic substructure. In addition, a 6-year follow-up is presented. The FRC-FPD fully restored the single missing molar with simple and conservative intracoronal preparations in the proximal teeth and was deemed clinically acceptable after the evaluation period. The clinical procedures to build a FRC-FPD with a prefabricated fiber-reinforced pontic substructure typically are finished by the clinician in 1 or 2 visits without laboratory assistance, making it a viable alternative for patients who cannot afford implant-based treatment or a conventional metal-ceramic FPD. PMID:23649577

Soares, Carlos Jose; Barreto, Bruno Castro Ferreira; Santos-Filho, Paulo Cesar de Freitas; Raposo, Luis Henrique de Araujo; Martins, Luis Roberto Marcondes

2013-01-01

134

Role of multiple cusps in tooth fracture.  

PubMed

The role of multiple cusps in the biomechanics of human molar tooth fracture is analysed. A model with four cusps at the bite surface replaces the single dome structure used in previous simulations. Extended finite element modelling, with provision to embed longitudinal cracks into the enamel walls, enables full analysis of crack propagation from initial extension to final failure. The cracks propagate longitudinally around the enamel side walls from starter cracks placed either at the top surface (radial cracks) or from the tooth base (margin cracks). A feature of the crack evolution is its stability, meaning that extension occurs steadily with increasing applied force. Predictions from the model are validated by comparison with experimental data from earlier publications, in which crack development was followed in situ during occlusal loading of extracted human molars. The results show substantial increase in critical forces to produce longitudinal fractures with number of cuspal contacts, indicating a capacity for an individual tooth to spread the load during mastication. It is argued that explicit critical force equations derived in previous studies remain valid, at the least as a means for comparing the capacity for teeth of different dimensions to sustain high bite forces. PMID:24755003

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

2014-07-01

135

Need of implant dentistry at undergraduate dental curriculum in Indian dental colleges.  

PubMed

Edentulism is the major problem in the developing countries, and is widely spread in the current population, although the prevalence is declining and incidence of tooth loss is decreasing in the developed nations. The prevalence of edentulism in India varies from 60% to 69% of 25 years and above age group. It is obvious that the number of lost teeth increases with age leading to an increase in prevalence of partially edentulous patients. From a biological point of view, the replacement of a single missing tooth with an implant rather than a three-unit fixed partial denture, and the implant-supported complete denture has been proved more efficient in improving the mastication and maintaining the bone for a longer time and also more cost-effective treatment. Many dental schools throughout Europe and America have to a various extent introduced implant dentistry as part of the compulsory undergraduate curriculum. Thus, it becomes more essential to introduce implant dentistry at undergraduate level in Indian dental schools to manage the higher percentage of edentulism. PMID:22048585

Chowdhary, Ramesh; Chowdhary, Nagalakshmi

2011-01-01

136

A device for the implantation of multiple cellular deposits into a large volume of brain from a single cannula site.  

PubMed

Current grafting techniques for the treatment of Parkinson's disease incompletely restore the dopaminergic innervation of the caudate/putamen and while, in successful cases, bradykinesia and rigidity are reduced, tremor is largely unaffected. Increasing the number of cellular deposits would allow grafted neurons to be dispersed more widely within the host brain. This might be expected to lead to a more complete reinnervation of the caudate/putamen and therefore a better clinical result. In order to increase the volume of brain accessible to reinnervation without increasing the number of needle passages through the cortex, we have designed a device which allows a Teflon tube to be extruded sideways from the end of a stainless steel cannula. Through this tube, cells can be implanted at some distance in any radial direction from the axis of the cannula. Using such a device we have made up to 12 deposits of lac-z-labeled cells via a single cannula entry into the rat brain, at distances of up to 5 mm from the axis of the cannula. We propose that a similar device could be used to graft embryonic neurons into the human brain. PMID:8620932

Brecknell, J E; Fawcett, J W

1996-04-01

137

Osseointegrated implant failures.  

PubMed

This article discusses the criteria used for implant success and failure, the classification of implant failures, the causative factors, and diagnosis of the failing and failed implant. In spite of the impressive success rates of osseointegrated dental implants, failures occur and in some studies the incidence of failure is high. Many studies do not use objective criteria to define success and confuse survival with success. The criteria used affect reported success rates. Implant failures may occur early (primary) after implant placement or after the implant is loaded (secondary). There is no single aetiological factor and failures have been attributed to poor surgical technique, host factors that impair healing, poor bone quality, peri-implant infections, poor prosthesis design and traumatic loading conditions. Early diagnosis of problems is critical and every effort should be made to treat the problem while the damage can still be managed or even reversed. PMID:10686922

O'Mahony, A; Spencer, P

1999-01-01

138

[Tooth eruption disturbances and syndromes].  

PubMed

In the tooth eruption mechanism, various disturbances can appear as a result of gene mutations, a consequence of which can be that tooth eruption does not occur. There are 5 syndromes which involve the complete failure of several or even all teeth to erupt, specifically: cleidocranial dysplasia, Gardner's syndrome, osteopetrosis, mucopolysaccharidosis and GAPO syndrome. Some are very rare and will seldom be encountered in a dental practice, but they show how vulnerable the tooth eruption mechanism is. Dentists are generally the ones who identify a tooth eruption problem in a patient. Since syndromes can be associated with other disorders, additional investigation by a clinical geneticist is always important when a syndrome is suspected. PMID:24881265

Oosterkamp, B C M; Ockeloen, C W; Carels, C E L; Kuijpers-Jagtman, A M

2014-04-01

139

New Perspectives on Tooth Wear  

PubMed Central

Some of the efforts that have been made to document tooth wear are reviewed here with an emphasis on nonhuman mammals, literature with which dentists may not be very familiar. We project a change in research strategy from the description of wear at various scales of measurement towards investigation of the mechanical mechanisms that actually create the texture of a worn surface. These studies should reveal exactly how tooth tissue is lost and what aspects of the structure of dental tissues affect this. The most important aspects of the interaction between the tooth surface and wear particles would appear to be particle size, particle shape, their mechanical properties with respect to those of tooth tissues, and the influence of saliva. PMID:22536239

Lucas, Peter W.; Omar, Ridwaan

2012-01-01

140

STEM CELLS FOR TOOTH ENGINEERING  

Microsoft Academic Search

Tooth development results from sequential and reciprocal interactions between the oral epithelium and the underlying neural crest-derived mesenchyme. The generation of dental structures and\\/or entire teeth in the laboratory depends upon the manipulation of stem cells and requires a synergy of all cellular and molecular events that finally lead to the formation of tooth-specific hard tissues, dentin and enamel. Although

G. Bluteau; H. U. Luder; C. De Bari; T. A. Mitsiadis; Aberdeen AB

2008-01-01

141

A novel root analogue dental implant using CT scan and CAD/CAM: selective laser melting technology.  

PubMed

Direct laser metal forming (DLMF) is a new technique which allows solids with complex geometry to be produced by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model. For dental implants, the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer by layer, the desired object. Modern computed tomography (CT) acquisition and 3D image conversion, combined with the DLMF process, allows the fabrication of custom-made, root-analogue implants (RAI), perfect copies of the radicular units that need replacing. This report demonstrates the successful clinical use of a custom-made, root-analogue DLMF implant. CT images of the residual non-restorable root of a right maxillary premolar were acquired and modified with specific software into a 3D model. From this model, a custom-made, root-analogue, DLMF implant was fabricated. Immediately after tooth extraction, the root-analogue implant was placed in the extraction socket and restored with a single crown. At the 1-year follow-up examination, the custom-made implant showed almost perfect functional and aesthetic integration. The possibility of fabricating custom-made, root-analogue DLMF implants opens new interesting perspectives for immediate placement of dental implants. PMID:22377004

Figliuzzi, M; Mangano, F; Mangano, C

2012-07-01

142

Detecting gear tooth fracture in a high contact ratio face gear mesh  

NASA Technical Reports Server (NTRS)

This paper summarized the results of a study in which three different vibration diagnostic methods were used to detect gear tooth fracture in a high contact ratio face gear mesh. The NASA spiral bevel gear fatigue test rig was used to produce unseeded fault, natural failures of four face gear specimens. During the fatigue tests, which were run to determine load capacity and primary failure mechanisms for face gears, vibration signals were monitored and recorded for gear diagnostic purposes. Gear tooth bending fatigue and surface pitting were the primary failure modes found in the tests. The damage ranged from partial tooth fracture on a single tooth in one test to heavy wear, severe pitting, and complete tooth fracture of several teeth on another test. Three gear fault detection techniques, FM4, NA4*, and NB4, were applied to the experimental data. These methods use the signal average in both the time and frequency domain. Method NA4* was able to conclusively detect the gear tooth fractures in three out of the four fatigue tests, along with gear tooth surface pitting and heavy wear. For multiple tooth fractures, all of the methods gave a clear indication of the damage. It was also found that due to the high contact ratio of the face gear mesh, single tooth fractures did not significantly affect the vibration signal, making this type of failure difficult to detect.

Zakrajsek, James J.; Handschuh, Robert F.; Lewicki, David G.; Decker, Harry J.

1995-01-01

143

The Human Sweet Tooth  

PubMed Central

Humans love the taste of sugar and the word "sweet" is used to describe not only this basic taste quality but also something that is desirable or pleasurable, e.g., la dolce vita. Although sugar or sweetened foods are generally among the most preferred choices, not everyone likes sugar, especially at high concentrations. The focus of my group's research is to understand why some people have a sweet tooth and others do not. We have used genetic and molecular techniques in humans, rats, mice, cats and primates to understand the origins of sweet taste perception. Our studies demonstrate that there are two sweet receptor genes (TAS1R2 and TAS1R3), and alleles of one of the two genes predict the avidity with which some mammals drink sweet solutions. We also find a relationship between sweet and bitter perception. Children who are genetically more sensitive to bitter compounds report that very sweet solutions are more pleasant and they prefer sweet carbonated beverages more than milk, relative to less bitter-sensitive peers. Overall, people differ in their ability to perceive the basic tastes, and particular constellations of genes and experience may drive some people, but not others, toward a caries-inducing sweet diet. Future studies will be designed to understand how a genetic preference for sweet food and drink might contribute to the development of dental caries. PMID:16934118

Reed, Danielle R; McDaniel, Amanda H

2006-01-01

144

Intense intrashell luminescence of Eu-doped single ZnO nanowires at room temperature by implantation created Eu-Oi complexes.  

PubMed

Successful doping and excellent optical activation of Eu(3+) ions in ZnO nanowires were achieved by ion implantation. We identified and assigned the origin of the intra-4f luminescence of Eu(3+) ions in ZnO by first-principles calculations to Eu-Oi complexes, which are formed during the nonequilibrium ion implantation process and subsequent annealing at 700 °C in air. Our targeted defect engineering resulted in intense intrashell luminescence of single ZnO:Eu nanowires dominating the photoluminescence spectrum even at room temperature. The high intensity enabled us to study the luminescence of single ZnO nanowires in detail, their behavior as a function of excitation power, waveguiding properties, and the decay time of the transition. PMID:24972185

Geburt, Sebastian; Lorke, Michael; da Rosa, Andreia L; Frauenheim, Thomas; Röder, Robert; Voss, Tobias; Kaiser, Uwe; Heimbrodt, Wolfram; Ronning, Carsten

2014-08-13

145

Reproducibility of the Pink Esthetic Score-Rating Soft Tissue Esthetics Around Single-Implant Restorations with Regard to Dental Observer Specialization  

Microsoft Academic Search

Purpose: The pink esthetic score (PES) evaluates the esthetic outcome of soft tissue around implant-supported single crowns in the anterior zone by awarding seven points for the mesial and distal papilla, soft-tissue level, soft-tissue contour, soft-tissue color, soft-tissue texture, and alveolar process deficiency. The aim of this study was to measure the reproducibility of the PES and assess the influence

PETER GEHRKE; MARKUS LOBERT; GÜNTER DHOM

2008-01-01

146

Characterization of the lattice defects in Ge-ion implanted ZnO bulk single crystals by Rutherford Backscattering: Origins of low resistivity  

NASA Astrophysics Data System (ADS)

A Ge ion implantation using a multiple-step energy into ZnO bulk single crystals is performed (net concentration: 2.6 × 1020 cm-3). The origins of low resistivity of the Ge implanted ZnO samples are studied by Rutherford backscattering spectroscopy (RBS), photoluminescence (PL). The resistivity measured by Van der Pauw method decreases from ˜103 ?cm for the un-implanted samples to 1.45 × 10-2 ?cm for the as-implanted samples, originating from the lattice displacement of Zn (Zni) (˜30 meV [Look et al., Phys. Rev. Lett. 82, 2552 (1999)]), the existence of which is revealed by the RBS measurements. In contrast, the 1000 °C annealed samples show the higher resistivity of 6.26 × 10-1 ?cm, indicating that the Zni related defects decrease but still remain despite the annealing. A new PL emission appears at around 372 nm (3.33 eV) in the annealed samples, suggesting a Ge donor with an activation energy of 100 meV. This value corresponds to the activation energy (102 meV) of a Ge donor estimated from the temperature dependence of carrier concentration. These results suggest that the resistivity in the 1000 °C annealed samples results from both the Zni related defects and the electrically activated Ge donor.

Kamioka, K.; Oga, T.; Izawa, Y.; Kuriyama, K.; Kushida, K.

2013-07-01

147

Measurements of the diffusion of iron and carbon in single crystal NiAl using ion implantation and secondary ion mass spectrometry  

SciTech Connect

Classical diffusion measurements in intermetallic compounds are often complicated by low diffusivities or low solubilities of the elements of interest. Using secondary ion mass spectrometry for measurements over a relatively shallow spatial range may be used to solve the problem of low diffusivity. In order to simultaneously obtain measurements on important impurity elements with low solubilities, the authors have used ion implantation to supersaturate a narrow layer near the surface. Single crystal NiAl was implanted with either {sup 12}C or both {sup 56}Fe and {sup 12}C in order to investigate the measurement of substitutional (Fe) versus interstitial (C) tracer diffusion and the cross effect of both substitutional and interstitial diffusion. When C alone was implanted negligible diffusion was observed over the range of times and temperatures investigated. When both Fe and C were implanted together significantly enhanced diffusion of the C was observed, which is apparently associated with the movement of Fe. This supports one theory of dynamic strain aging in Fe alloys NiAl.

Hanrahan, R.J. Jr. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.; Withrow, S.P. [Oak Ridge National Lab., TN (United States). Solid State Div.; Puga-Lambers, M. [Univ. of Florida, Gainesville, FL (United States)

1998-12-31

148

Cochlear Implants  

MedlinePLUS

... Need to Know Before, During, & After Implant Surgery Recalls and Safety Cochlear Implants View movie of the ... cochlear implants, and provide news about cochlear implant recalls and safety issues. You can find information here ...

149

[Aftercare for durability and profitability of single-unit and multi-unit fixed dental prostheses].  

PubMed

An important aim ofa treatment with single-unit and multi-unit fixed dental prostheses is a durable and profitable treatment outcome. That requires aftercare, too. First, the frequency of routine oral examinations should be assessed, using an individual risk profile. The objectives of the routine oral examinations are the prevention and, when necessary, the treatment of pathological conditions and complications. With regard to prevention, attention should be paid to information and instruction, oral biofilm and calculus, non-functional activities, hard tooth tissues, periodontal and peri-implant tissues, and saliva. Subsequently, it can be determined whether the intended durability and profitability have been achieved or can still be achieved, whether or not through indicated adjustments. Special attention should be paid to endodontically treated teeth. Restorative, repair or replacement treatments may be indicated in case ofcomplications, such as loose single- or multi-unitfixed dental prosthesis, fracture of a fixed dental prosthesis unit, lost tooth pulp vitality, tooth root fracture, and implant or implant abutment problems. PMID:23923444

de Baat, C; van Loveren, C; van der Maarel-Wierink, C D; Witter, D J; Creugers, N H J

2013-01-01

150

Interleukin-1? level in peri-implant crevicular fluid and its correlation with the clinical and radiographic parameters  

PubMed Central

Background and Objectives: Assessing only the clinical and radiographic parameters for evaluation of dental implants may not be enough as they often reflect extensive inflammatory changes in the periodontal tissues. As peri-implant crevicular fluid (PICF) can give us a more prompt and objective measure of the disease activity, the purpose of this case series is to assess the peri-implant health status of single tooth dental implants not only clinically and radiographically but also biochemically. Materials and Methods: Thirteen patients were subjected to dental implants at single edentulous sites using a conventional surgical approach. At baseline, 6 months, and 12 months after implant placement, the clinical and radiographic parameters were recorded. Additionally, IL-1? in PICF was estimated using the ELISA kit at 6th and 12th month. Results: The clinical and radiographic parameters differed significantly around the implants at different time intervals with IL-1? levels showing highly significant differences between 6 months (31.79 ± 12.26 pg/?l) and 12 months (113.09 ± 51.11 pg/?l). However, Spearman's correlation coefficient showed no correlation with the clinical and radiographic parameters. Interpretation and Conclusion: Assessment of the various parameters confirmed that all the implants had a healthy peri-implant status. Although the levels of IL-1? in PICF were elevated at the 12th month, they were well within the healthy range as observed by previous studies. This indicates that IL-1?, a biochemical marker, can be used as an adjunct to clinical and radiographic parameters in the assessment of EARLY inflammatory changes around implants. PMID:24872632

Kajale, Aniruddha M.; Mehta, Dhoom S.

2014-01-01

151

Molecular Genetics of Tooth Development  

PubMed Central

Organogenesis depends upon a well-ordered series of inductive events involving coordination of molecular pathways that regulate the generation and patterning of specific cell types. Key questions in organogenesis involve the identification of the molecular mechanisms by which proteins interact to organize distinct pattern formation and cell fate determination. Tooth development is an excellent context for investigating this complex problem because of the wealth of information emerging from studies of model organisms and human mutations. Since there are no obvious sources of stem cells in adult human teeth, any attempt to create teeth de novo will likely require the re-programming of other cell types. Thus, the fundamental understanding of the control mechanisms responsible for normal tooth patterning in the embryo will help us understand cell fate specificity and may provide valuable information towards tooth organ regeneration. PMID:19875280

Bei, Marianna

2009-01-01

152

Has tooth structure been replaced?  

PubMed

In my opinion, there is an obvious trend in the dental literature and in continuing education courses to promote overcutting teeth when preparing them for restorations. There are many reasons for overcutting. Some feel that there is a more optimum esthetic potential when the teeth are prepared more deeply, which is a debatable view. Others are using all-ceramic crowns or polymer crowns when other types of less radical crowns could be used. There also is a significant tendency to prepare teeth for crowns instead of for onlays or inlays, thereby removing more tooth structure than is necessary. High-speed dental air rotor or electric handpieces can cause inadvertent removal of more tooth structure than is necessary. Using large burs can overcut tooth structure, and teeth should be reversed. PMID:11811729

Christensen, Gordon J

2002-01-01

153

Characterization of single-sided gate-to-drain non-overlapped implantation nMOSFETs for multi-functional non-volatile memory applications  

NASA Astrophysics Data System (ADS)

Novel single-sided non-overlapped implantation (SNOI) nMOSFETs are characterized for their capability of multiple programmable memory functions. These devices can be operated as mask ROMs, EEPROMs or anti-fuses by using a pure logic processing. To function as mask ROMs, they can be mask-coded with the source drain extension (SDE) implantation. They can also be used as EEPROM devices by trapping charges in the side-wall nitride spacers. Furthermore, SNOI devices can be used as antifuses by introducing the punch-through stress at the drain side. The SNOI devices were successfully demonstrated for antifuse operations with an extremely high program/initial readout current ratio exceeding 10 9 and a program speed as high as 1 ?s. These novel SNOI devices not only provide non-volatile memory solutions in standard CMOS processing but also give a flexible choice among mask ROM, antifuse and EEPROM functions.

Jeng, E. S.; Chen, Y. F.; Chang, C. C.; Peng, K. M.; Chou, S. W.; Ho, C. W.; Huang, C. F.; Gong, J.

2012-02-01

154

Detecting Gear Tooth Fatigue Cracks in Advance of Complete Fracture  

NASA Technical Reports Server (NTRS)

Results of using vibration-based methods to detect gear tooth fatigue cracks are presented. An experimental test rig was used to fail a number of spur gear specimens through bending fatigue. The gear tooth fatigue crack in each test was initiated through a small notch in the fillet area of a tooth on the gear. The primary purpose of these tests was to verify analytical predictions of fatigue crack propagation direction and rate as a function of gear rim thickness. The vibration signal from a total of three tests was monitored and recorded for gear fault detection research. The damage consisted of complete rim fracture on the two thin rim gears and single tooth fracture on the standard full rim test gear. Vibration-based fault detection methods were applied to the vibration signal both on-line and after the tests were completed. The objectives of this effort were to identify methods capable of detecting the fatigue crack and to determine how far in advance of total failure positive detection was given. Results show that the fault detection methods failed to respond to the fatigue crack prior to complete rim fracture in the thin rim gear tests. In the standard full rim gear test all of the methods responded to the fatigue crack in advance of tooth fracture; however, only three of the methods responded to the fatigue crack in the early stages of crack propagation.

Zakrajsek, James J.; Lewicki, David G.

1996-01-01

155

Tooth whitening: concepts and controversies.  

PubMed

Today's society dictates that it is the norm for people to have straight, white teeth. The demand therefore for tooth whitening in dental practice has increased exponentially over the last decade. A common approach to achieving this goal is by bleaching. This article discusses clinical aspects of dental bleaching by providing an evidence-based review of current literature. Topics covered include aetiology of tooth discolouration, indications for bleaching, its mode of action, different types of bleaching regimes, indications and potential side effects. PMID:17948744

Fearon, Johnny

2007-01-01

156

Safety controversies in tooth bleaching.  

PubMed

Tooth bleaching using peroxide-based materials is an effective procedure in dentistry. Studies provide evidence on the safety of bleaching by dental professionals. However, concerns and controversy remain regarding the safety of bleaching systems that do not involve dental professionals, especially those available at mall kiosks, salons, spas, and cruise ships. Bleaching causes tooth sensitivity and/or gingival irritation in a significant portion of patients. Bleaching requires proper examination, diagnosis, and treatment plan, which can be performed appropriately only by dental professionals; therefore, involvement of dental professionals in bleaching is necessary to maximize the efficacy and minimize potential risks. PMID:21473992

Li, Yiming

2011-04-01

157

Totally implantable venous access devices: retrospective analysis of different insertion techniques and predictors of complications in 796 devices implanted in a single institution  

PubMed Central

Background The aim of this study was to assess the efficacy and safety of totally implanted vascular devices (TIVAD) using different techniques of insertion. Methods We performed a retrospective study using a prospective collected database of 796 consecutive oncological patients in which TIVADs were inserted. We focused on early and late complications following different insertion techniques (surgical cutdown, blind and ultrasound guided percutaneous) according to different techniques. Results Ultrasound guided technique was used in 646 cases, cephalic vein cutdown in 102 patients and percutaneous blind technique in 48 patients. The overall complication rate on insertion was 7.2% (57 of 796 cases). Early complications were less frequent using the ultrasound guided technique: arterial puncture (p?=?0.009), technical failure (p?=?0.009), access site change after first attempt (p?=?0.002); pneumothorax occurred in 4 cases, all using the blind percutaneus technique. Late complications occurred in 49 cases (6.1%) which required TIVAD removal in 43 cases and included: sepsis (29 cases), thrombosis (3 cases), dislocation (7 cases), skin dehiscence (3 cases), and severe pain (1 case). Conclusion Ultrasound guided technique is the safest option for TIVAD insertion, with the lowest rates of immediate complications. PMID:24886342

2014-01-01

158

Biology of tooth replacement in amniotes  

PubMed Central

Tooth replacement is a common trait to most vertebrates, including mammals. Mammals, however, have lost the capacity for continuous tooth renewal seen in most other vertebrates, and typically have only 1–2 generations of teeth. Here, we review the mechanisms of tooth replacement in reptiles and mammals, and discuss in detail the current and historical theories on control of timing and pattern of tooth replacement and development. PMID:23788284

Whitlock, John A; Richman, Joy M

2013-01-01

159

Charcot-Marie-Tooth Disease  

Microsoft Academic Search

Charcot-Marie-Tooth disease (CMT) or hereditary motor and sensory neuropathy constitutes a genetically heterogeneous group of diseases that affect the peripheral nervous system. CMT is characterized by degeneration or abnormal development of the peripheral nerve and is transmitted with different genetic patterns. In most cases, the disease starts in infancy. Its symptoms, among others, are an awkward gait; muscular atrophy of

Carlos Casasnovas; Luis Miguel Cano; Antonia Albertí; Maria Céspedes; Gillem Rigo

2008-01-01

160

A two DOF simulation of meshing in spur gear sets with modelling of the effect of individual tooth mass  

NASA Astrophysics Data System (ADS)

A Two-Degree Of Freedom analytical model of meshing in a single-stage spur gear set was developed and used for time-domain dynamic simulation. Apart from the time-varying tooth stiffness, the individual tooth mass, reduced to the meshing point, was also taken into consideration and modeled. The simulations that were performed by means of MatLab software using numerical methods highlight the effect of the individual tooth mass in the dynamic response of the gear stage.

Komitopoulos, Nikolaos; Vakouftsis, Christos

2014-10-01

161

Immediate placement of implant in fresh extraction socket with early loading  

PubMed Central

Implant placement in maxillary anterior region has most aesthetic challenges in implant dentistry because tooth loss lead to bone resorption and collapse of gingival architecture, which lead to aesthetic compromise and inadequate bone for implant placement. Immediate implant placement into fresh extraction socket reduces the treatment time, cost, preserved the gingival aesthetic and increases the comfort of the patient. This article describes the procedure for immediate implant placement in fresh extraction socket and early loading of implant with zirconia crown. Clinical and radiographic examination revealed width and length of the tooth for selecting implant size and design. Cement retained zirconia crown was used for early loading. Implant was successfully loaded and was functional during 36 months follow up period. Immediate placement and early loading of dental implant provides advantages like fewer surgical procedures, shorter treatment time, and improved aesthetic and psychological confidence. PMID:23230368

Singh, Archana; Gupta, Aratee; Yadav, Ashish; Chaturvedi, T. P.; Bhatnagar, Atul; Singh, B. P.

2012-01-01

162

Sequential provisional implant prosthodontics therapy.  

PubMed

The fabrication and long-term use of first- and second-stage provisional implant prostheses is critical to create a favorable prognosis for function and esthetics of a fixed-implant supported prosthesis. The fixed metal and acrylic resin cemented first-stage prosthesis, as reviewed in Part I, is needed for prevention of adjacent and opposing tooth movement, pressure on the implant site as well as protection to avoid micromovement of the freshly placed implant body. The second-stage prosthesis, reviewed in Part II, should be used following implant uncovering and abutment installation. The patient wears this provisional prosthesis until maturation of the bone and healing of soft tissues. The second-stage provisional prosthesis is also a fail-safe mechanism for possible early implant failures and also can be used with late failures and/or for the necessity to repair the definitive prosthesis. In addition, the screw-retained provisional prosthesis is used if and when an implant requires removal or other implants are to be placed as in a sequential approach. The creation and use of both first- and second-stage provisional prostheses involve a restorative dentist, dental technician, surgeon, and patient to work as a team. If the dentist alone cannot do diagnosis and treatment planning, surgery, and laboratory techniques, he or she needs help by employing the expertise of a surgeon and a laboratory technician. This team approach is essential for optimum results. PMID:23220306

Zinner, Ira D; Markovits, Stanley; Jansen, Curtis E; Reid, Patrick E; Schnader, Yale E; Shapiro, Herbert J

2012-01-01

163

Axial relationship between dental implants and teeth/implants: a radiographic study.  

PubMed

The relationship of dental implants with neighboring teeth will affect both occlusal relationship and distribution of forces; thus, the purpose of this study was to examine implants' axial relationship with adjacent and opposing teeth/implants. Data of dental implants patients was retrieved. Panoramic X rays were digitized. Computer-based software was used to measure the angular relationship between the implants and adjacent/opposing teeth and implants. Data was further sorted by the mode of placement and implants position. 50 patients (219 implants) were included. Mean angle to adjacent tooth/implant was 178.71° ± 9.18° (range 129.7°-206°). Implants were more parallel to adjacent teeth (180.99° ± 1.06°) than to adjacent implants (176.32° ± 0.54°; P = .0001). Mean angular relationship to opposite tooth was 167.88° ± 8.92° (range 137.7°-179.8°). Implants that were placed freehand or with positional guide had similar intra-arch relationship (178.22° and 178.81°, respectively) and similar inter-arch angulations (164.46° and 167.74°). Molars had greater deviation of the angular relationship (175.54°) compared to premolars (181.62°) and incisors (180.55°, P = .0001). Implants placed in the maxilla had smaller axial deviation compared to implants in the mandible (180.41° ± 0.64 vs 177.14° ± 1.02; P = .0081). Good axial relationship may be obtained in most implants placed by an experienced clinician, even when placed freehand. The mandibular posterior region is more prone to axial deviation and as such requires special attention. PMID:25106006

Machtei, Eli E; Oettinger-Barak, Orit; Horwitz, Jacob

2014-08-01

164

Continuous tooth generation in mouse is induced by activated epithelial Wnt/?-catenin signaling  

PubMed Central

The single replacement from milk teeth to permanent teeth makes mammalian teeth different from teeth of most nonmammalian vertebrates and other epithelial organs such as hair and feathers, whose continuous replacement has been linked to Wnt signaling. Here we show that mouse tooth buds expressing stabilized ?-catenin in epithelium give rise to dozens of teeth. The molar crowns, however, are typically simplified unicusped cones. We demonstrate that the supernumerary teeth develop by a renewal process where new signaling centers, the enamel knots, bud off from the existing dental epithelium. The basic aspects of the unlocked tooth renewal can be reproduced with a computer model on tooth development by increasing the intrinsic level of activator production, supporting the role of ?-catenin pathway as an upstream activator of enamel knot formation. These results may implicate Wnt signaling in tooth renewal, a capacity that was all but lost when mammals evolved progressively more complicated tooth shapes. PMID:17121988

Jarvinen, Elina; Salazar-Ciudad, Isaac; Birchmeier, Walter; Taketo, Makoto M.; Jernvall, Jukka; Thesleff, Irma

2006-01-01

165

Paddle versus cylindrical leads for percutaneous implantation in spinal cord stimulation for failed back surgery syndrome: a single-center trial.  

PubMed

Objective?Spinal cord stimulation is an interventional treatment for chronic pain syndromes such as failed back surgery syndrome (FBSS), and it utilizes either cylindrical or paddle electrodes placed percutaneously into the epidural space. This prospective nonrandomized single-center study investigated the specific advantages and disadvantages of percutaneously implanted paddle and cylindrical leads in patients with FBSS. Methods?Over a 2-year period, 100 patients with FBSS (43 men; 57 women; mean age: 56.3 years) were included. Paddle leads were placed percutaneously under local anesthesia in 50 patients; conventional percutaneous cylindrical lead implantation was performed in the other 50 patients (one lead permitted per patient). Follow-up included the Visual Analog Scale (VAS) assessment of pain and administration of the Oswestry Disability Questionnaire. Results?Similar significant pain reduction (69%) was demonstrated in both groups (VAS pre/post: paddle: 8.8/3.7; cylindrical: 8.5/3.8). Using the same perioperative protocol for each group, we observed higher dislocation and infection rates for the cylindrical group (14% and 10%, respectively) than for the paddle group (6% and 2%, respectively). Conclusion?Minimally invasive percutaneous paddle and cylindrical leads are safe and effective, have low complication rates, and perform well in patients with FBSS. Both devices can be implanted using a local anesthetic, so that intraoperative and reproducible testing stimulation can be performed for sufficient paresthesia overlap prior to permanent device fixation. PMID:24793061

Kinfe, Thomas M; Quack, Florian; Wille, Christian; Schu, Stefan; Vesper, Jan

2014-11-01

166

In vitro comparison of resistance to implant failure in unstable trochanteric fractures fixed with intramedullary single screw versus double screw device  

PubMed Central

Background: The purpose of this study was to compare the resistance of intramedullary single screw device (Gamma nail) and double screw device proximal femoral nail (PFN) in unstable trochanteric fractures in terms of the number of cycles sustained, subsidence and implant failure in an axial loading test in cadaveric femora. Materials and Methods: The study was conducted on 18 dry cadaveric femoral specimens, 9 of these were implanted with a Gamma nail and 9 with PFN. There was no significant difference found in average dual energy X-ray absorptiometry value between both groups. The construct was made unstable (AO type 31A3.3) by removing a standard sized posteromedial wedge. These were tested on a cyclic physiological loading machine at 1 cycle/s with a load of 200 kg. The test was observed for 50,000 loading cycles or until implant failure, whichever occurred earlier. Peak displacements were measured and analysis was done to determine construct stiffness and gap micromotion in axial loading. Result: It was observed that there was statistically significant difference in terms of displacement at the fracture gap and overall construct stiffness of specimens of both groups. PFN construct group showed a mean subsidence of 1.02 mm and Gamma nail construct group showed mean subsidence of 2.36 mm after cycling. The average stiffness of Gamma nail group was 62.8 ± 8.4 N/mm which was significantly lower than average stiffness of the PFN group (80.4 ± 5.9 N/mm) (P = 0.03). In fatigue testing, 1 out of 9 PFN bone construct failed, while 5 of 9 Gamma nail bone construct failed. Conclusion: When considering micromotion (subsidence) and incidence of implant/screw failure, double screw device (PFN) had statistically significant lower micromotion across the fracture gap with axial compression and lower incidence of implant failure. Hence, double screw device (PFN) construct had higher stability compared to single screw device (GN) in an unstable trochanteric fracture femur model. PMID:24932039

Rastogi, Amit; Arun, GR; Singh, Vakil; Singh, Anant; Singh, Ashutosh K; Kumaraswamy, Vinay

2014-01-01

167

An automatic and effective tooth isolation method for dental radiographs  

NASA Astrophysics Data System (ADS)

Tooth isolation is a very important step for both computer-aided dental diagnosis and automatic dental identification systems, because it will directly affect the accuracy of feature extraction and, thereby, the final results of both types of systems. This paper presents an effective and fully automatic tooth isolation method for dental X-ray images, which contains up-per-lower jaw separation, single tooth isolation, over-segmentation verification, and under-segmentation detection. The upper-lower jaw separation mechanism is based on a gray-scale integral projection to avoid possible information loss and incorporates with the angle adjustment to handle skewed images. In a single tooth isolation, an adaptive windowing scheme for locating gap valleys is proposed to improve the accuracy. In over-segmentation, an isolation-curve verification scheme is proposed to remove excessive curves; and in under-segmentation, a missing-teeth detection scheme is proposed. The experimental results demonstrate that our method achieves the accuracy rates of 95.63% and 98.71% for the upper and lower jaw images, respectively, from the test database of 60 bitewing dental radiographs, and performs better for images with severe teeth occlusion, excessive dental works, and uneven illumination than that of Nomir and Abdel-Mottaleb's method. The method without upper-lower jaw separation step also works well for panoramic and periapical images.

Lin, P.-L.; Huang, P.-W.; Cho, Y. S.; Kuo, C.-H.

2013-03-01

168

Single phase formation of Co-implanted ZnO thin films by swift heavy ion irradiation: Optical studies  

SciTech Connect

Low temperature photoluminescence and optical absorption studies on 200 MeV Ag{sup +15} ion irradiated Co-implanted ZnO thin films were studied. The Co clusters present in as implanted samples were observed to be dissolved using 200 MeV Ag{sup +15} ion irradiation with a fluence of 1x10{sup 12} ions/cm{sup 2}. The photoluminescence spectrum of pure ZnO thin film was characterized by the I{sub 4} peak due to the neutral donor bound excitons and the broad green emission. The Co-doped ZnO films show three sharp levels and two shoulders corresponding to 3t{sub 2g} and 2e{sub g} levels of crystal field splitted Co d orbitals, respectively. The ultraviolet-visible absorption spectroscopy also shows the systematic variation of band gap after 200 MeV Ag{sup +15} ion irradiation.

Kumar, Ravi; Singh, Fouran; Angadi, Basavaraj; Choi, Ji-Won; Choi, Won-Kook; Jeong, Kwangho; Song, Jong-Han; Khan, M. Wasi; Srivastava, J. P.; Kumar, Ajay; Tandon, R. P. [Materials Science Division, Inter-University Accelerator Centre, P.O. Box 10502, Aruna Asaf Ali Marg, New Delhi 110067 (India); Thin Films Materials Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Institute of Physics and Applied Physics, Yonsei University, Shincheon-dong 134, Seoul 120-749 (Korea, Republic of); Advanced Analysis Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Department of Physics, Aligarh Muslim University, Aligarh 202002 (India); Department of Physics and Astrophysics, Delhi University, Delhi 110007 (India)

2006-12-01

169

Anatomically Shaped Tooth and Periodontal Regeneration by Cell Homing  

PubMed Central

Tooth regeneration by cell delivery encounters translational hurdles. We hypothesized that anatomically correct teeth can regenerate in scaffolds without cell transplantation. Novel, anatomically shaped human molar scaffolds and rat incisor scaffolds were fabricated by 3D bioprinting from a hybrid of poly-?-caprolactone and hydroxyapatite with 200-µm-diameter interconnecting microchannels. In each of 22 rats, an incisor scaffold was implanted orthotopically following mandibular incisor extraction, whereas a human molar scaffold was implanted ectopically into the dorsum. Stromal-derived factor-1 (SDF1) and bone morphogenetic protein-7 (BMP7) were delivered in scaffold microchannels. After 9 weeks, a putative periodontal ligament and new bone regenerated at the interface of rat incisor scaffold with native alveolar bone. SDF1 and BMP7 delivery not only recruited significantly more endogenous cells, but also elaborated greater angiogenesis than growth-factor-free control scaffolds. Regeneration of tooth-like structures and periodontal integration by cell homing provide an alternative to cell delivery, and may accelerate clinical applications. PMID:20448245

Kim, K.; Lee, C.H.; Kim, B.K.; Mao, J.J.

2010-01-01

170

Aggregatibacter Actinomycetemcomitans - A Tooth Killer?  

PubMed Central

Strong evidence is available on Aggregatibacter actinomycetemcomitans (A.a) on its role as the causative agent of localised juvenile periodontitis (LJP), a disease characterised by rapid destruction of the tooth-supporting tissues. This organism possesses a large number of virulence factors with a wide range of activities which enable it to colonise the oral cavity, invade periodontal tissues, evade host defences, initiate connective tissue destruction and interfere with tissue repair. Adhesion to epithelial and tooth surfaces is dependent on the presence of surface proteins and structures such as microvesicles and fimbriae. Invasion has been demonstrated in vivo and in vitro. The organism has a number of means of evading host defences which include: (i) production of leukotoxin; (ii) producing immunosuppressive factors; (iv) secreting proteases capable of cleaving IgG; and (v) producing Fc-binding. PMID:25302290

Ummer, Fajar; Dhivakar, C.P

2014-01-01

171

Towards tooth friendly soft drinks.  

PubMed

Most soft drinks contain high concentration of simple carbohydrates and have a pH of 3 or even lower. Therefore, they are harmful for tooth structure. A tooth friendly soft drink (T.F.S.D) should have the following characteristics and elements; fluoride (approximately 1 ppm), casein phosphopeptide-amorphous calcium phosphate (2%), xylitol (4-6g/serving), tea polyphenols (2-4 mg/ml), cranberry extract (250 mg/ml of the flavonoids quercetin and myricetin), sugar free, pH close to 5.5 and super oxygenation (240,000 ppm) vs. carbonation. T.F.S.D can be packaged in a container which gaseous oxygen is dissolved in a liquid in the form of bubbles. However, looking at opportunities for so-called sophisticated soft drinks, T.F.S.D will be an example for a functional and health oriented soft drink. PMID:19570614

Kolahi, Jafar; Fazilati, Mohamad; Kadivar, Mahdi

2009-10-01

172

Optical spectroscopy and tooth decay  

NASA Astrophysics Data System (ADS)

Optical spectroscopy in the ultraviolet, visible and mid-infrared spectral regions has been used to discriminate between healthy and diseased teeth of patients in the age range 15-75 years. Spectral scans of absorbance versus wavenumber and fluorescence intensity versus wavelength have been recorded and investigated for caries and periodontal disease. Such optical diagnostics can prove very useful in the early detection and treatment of tooth decay.

Misra, P.; De, T.; Singh, R.

2005-11-01

173

Epithelial histogenesis during tooth development.  

PubMed

This paper reviews the current understanding of the progressive changes mediating dental epithelial histogenesis as a basis for future collaborative studies. Tooth development involves morphogenesis, epithelial histogenesis and cell differentiation. The consecutive morphological stages of lamina, bud, cap and bell are also characterized by changes in epithelial histogenesis. Differential cell proliferation rates, apoptosis, and alterations in adhesion and shape lead to the positioning of groups of cells with different functions. During tooth histo-morphogenesis changes occur in basement membrane composition, expression of signalling molecules and the localization of cell surface components. Cell positional identity may be related to cell history. Another important parameter is cell plasticity. Independently of signalling molecules, which play a major role in inducing or modulating specific steps, cell-cell and cell-matrix interactions regulate the plasticity/rigidity of particular domains of the enamel organ. This involves specifying in space the differential growth and influences the progressive tooth morphogenesis by shaping the epithelial-mesenchymal junction. Deposition of a mineralized matrix determines the final shape of the crown. All data reviewed in this paper were investigated in the mouse. PMID:18656852

Lesot, H; Brook, A H

2009-12-01

174

Evaluation of crestal bone loss and stability of immediate functional loading versus immediate non-functional loading of single-mandibular posterior implants: A pilot randomized controlled clinical trial  

PubMed Central

Background: The aim of this study is to evaluate and compare the crestal bone loss and stability of single mandibular posterior dental implants placed in immediate functional loading (IFL) and immediate nonfunctional loading (INFL) during 6 months after placement. Materials and Methods: Forty single piece root form titanium implants were placed in 20 patients using IFL and INFL techniques. The change in the level of crestal bone was measured on standardized digital periapical radiographs using SOPRO imaging software and stability of implants using resonance frequency analyser taken at the baseline, 1, 3, and 6 months. The measurements were statistically analyzed using the independent and paired t-test (P < 0.05, statistically significant). Results: The mean change in the crestal bone level from baseline to 6 months was significant in both techniques. The implant stability quotient (ISQ) values at first and third months were lower than those at the baseline for both the groups. However, the ISQ values at the sixth month were similar to baseline for both the groups. The crestal bone changes and the ISQ values when compared between the groups showed no statistically significant difference. Conclusion: IFL of dental implants have equivalent results and success rate as that of immediately provisionalized implants within the limitations of this study.

Mantena, Satyanarayana Raju; Sivagami, G.; Gottumukkala, Sruthima NVS

2014-01-01

175

Cochlear implants in children.  

PubMed

In recent years, the House single-electrode cochlear implant has proven to be a clinically feasible prosthesis for profoundly deaf adults. Based on these findings, the decision was made to begin implanting those children who could not benefit from hearing aids. As of August 1982, 23 profoundly deaf children (ranging in age from 3.4 to 17.5 yrs) have received the cochlear implant. The majority were deafened by meningitis. Results to date indicate that children demonstrate sound field thresholds and receive timing/intensity information comparable to that of adult implant patients. Results have been extremely encouraging, but only long-term experience will determine the ultimate benefit of the implant in children. PMID:6687579

Eisenberg, L S; Berliner, K I; Thielemeir, M A; Kirk, K I; Tiber, N

1983-01-01

176

Optical mode confinement and selection in single-crystal sapphire fibers by formation of nanometer scale cavities with hydrogen ion implantation  

NASA Astrophysics Data System (ADS)

The excellent material properties of single crystal sapphire fibers promise great advantages in applications related to harsh environment optical sensing, high laser power delivery, and high-resolution/sensitivity optical spectroscopy. However, the lack of viable cladding for confining light propagation in sapphire fibers with negligible transmission loss has restricted their practical applications. Despite great efforts in engineering either a low-refractive-index cladding layer or highly reflective mirror layer as sapphire fiber surface coatings, confining light propagation within sapphire fibers remains difficult in practice since such surface coatings fail to function due to increased thermal stress and fast erosion in environments with extremely high temperatures (>1000 °C) and chemically reactive species/gases. Here, we demonstrate a method for creating nanoscale cavities/voids in sapphire as effective fiber cladding structures that are thermally robust even at 1700 °C using hydrogen ion implantation. Material analysis of implanted sapphire crystals indicates that such nanoscale cavities play a key role in reducing the refractive index in sapphire crystals.

Spratt, William; Huang, Mengbing; Murray, Thomas; Xia, Hua

2013-11-01

177

Esthesioneuroblastoma presenting as tooth pain.  

PubMed

Esthesioneuroblastoma, also called olfactory neuroblastoma, is a rare malignant tumor originating in the olfactory epithelium in the upper nasal cavity with intracranial extension and may also be associated with secondary sinus diseases. Esthesioneuroblastoma has been observed to cause death by distant metastasis or by invasion through the cribriform plate and secondary meningitis. It usually produces nasal obstruction, epistaxis and less commonly anosmia, headache and pain. We report a case of esthesioneuroblastoma in a 50-year-old female who reported with tooth pain as a presenting symptom. PMID:25364164

Devi, Parvathi; Bhavle, Radhika; Aggarwal, Avanti; Walia, Cherry

2014-09-01

178

Charcot-Marie-Tooth disease  

PubMed Central

Charcot-Marie-Tooth (CMT) disease is a heterogeneous group of genetic disorders presenting with the phenotype of a chronic progressive neuropathy affecting both the motor and sensory nerves. During the last decade over two dozen genes have been identified in which mutations cause CMT. The disease illustrates a multitude of genetic principles, including diverse mutational mechanisms from point mutations to copy number variation (CNV), allelic heterogeneity, age-dependent penetrance and variable expressivity. Population based studies have determined the contributions of the various genes to disease burden enabling evidence-based approaches to genetic testing. PMID:19277060

Szigeti, Kinga; Lupski, James R

2009-01-01

179

Long-term orthodontic tooth movement response to short-term force in the rat.  

PubMed

Both the amount of force applied and the duration of the application affect tooth movement. To study the effect of duration, adult male Sprague-Dawley rats were fitted with orthodontic appliances delivering a 40-gm initial mesial tipping force to the maxillary molars. The animals were divided into two longitudinal groups (I: 1 hour and II: 24 hours; N = 15). Sham-treated control (III) and 14 day (IV) continuous cross-sectional force tooth movement data were also included for comparison (72 rats per group). Extraoral cephalometric radiographs were obtained at appliance placement and at 1, 3, 5, 7, 10, & 14 days. Tooth movement was determined with respect to palatal implants. ANOVA indicated significant differences existed over time in each group (p = 0.0001). Continuous force applied for 14 days generated a classic three-part tooth movement curve. Short-term forces were characterized by initial mesial movement, a distal relapse period (d3-d5), and a late mesial movement period (d7-d14). The results suggest short-term forces of 1 and 24 hours initiate remodeling events, which result in tooth movement 7 to 14 days later and that the minimum effective duration of a 40-gm activation is less than 1 hour in this animal model. PMID:1416241

Gibson, J M; King, G J; Keeling, S D

1992-01-01

180

High-Dose-Rate Brachytherapy of a Single Implant With Two Fractions Combined With External Beam Radiotherapy for Hormone-Naive Prostate Cancer  

SciTech Connect

Purpose: To evaluate the preliminary outcomes of high-dose-rate (HDR) brachytherapy of a single implant with two fractions and external beam radiotherapy (EBRT) for hormone-naive prostate cancer. Methods and Materials: Between March 2000 and Sept 2003, a total of 53 patients with tumor Stage T1c-T3b N0 M0 prostate cancer were treated with HDR brachytherapy boost doses (7.5 Gy/fraction) and 50-Gy EBRT during a 5.5-week period. Median follow-up was 61 months. Patients were divided into groups with localized (T1c-T2b) and advanced disease (T3a-T3b). We used the American Society for Therapeutic Radiology and Oncology (ASTRO) definition for biochemical failure. According to recommendations of the Radiation Therapy Oncology Group-ASTRO Phoenix Consensus Conference, biochemical failure-free control rates (BF-FCRs) at 3 years were investigated as 2 years short of the median follow-up. Results: Between April 2000 and Sept 2007, Common Terminology Criteria for Adverse Events Version 2.0 late Grade 2 genitourinary and gastrointestinal toxicity rates were 0% and 3.8%, respectively. Erectile preservation was 25% at 5 years. Overall survival was 88.1% and cause-specific survival was 100%. At 3 years, ASTRO BF-FCRs of the localized and advanced groups were 100% and 42%, respectively (p = 0.001). Conclusions: The HDR brachytherapy of a single implant with two fractions plus EBRT is effective in treating patients with localized hormone-naive prostate cancer, with the least genitourinary and gastrointestinal toxicities; however, longer median BF-FCR follow-up is required to assess these findings.

Sato, Morio [Department of Radiology, Wakayama Medical University, Wakayama (Japan)], E-mail: morisato@mail.wakayama-med.ac.jp; Mori, Takashi [Department of Urology, Wakayama Medical University, Wakayama (Japan); Shirai, Shintaro; Kishi, Kazushi [Department of Radiology, Wakayama Medical University, Wakayama (Japan); Inagaki, Takeshi; Hara, Isao [Department of Urology, Wakayama Medical University, Wakayama (Japan)

2008-11-15

181

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2013-04-01

182

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2010-04-01

183

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2012-04-01

184

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2011-04-01

185

21 CFR 872.3580 - Preformed gold denture tooth.  

...2014-04-01 2014-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2014-04-01

186

Genotype, Phenotype, and Developmental Biology of Molar Tooth Characters  

E-print Network

may constrain as well as facilitate evolution of new tooth shapes, affecting how reliable dental among different organs, including teeth, limbs, and feathers. Furthermore, within a tooth ........................................ 172 Tooth Shape Development and Evolution

Jernvall, Jukka

187

Functional loads on freestanding and connected implants in three-unit mandibular prostheses opposing complete dentures: an in vivo study.  

PubMed

In vivo measurements of vertical forces and bending moments during biting and chewing were carried out on 10 three-unit prostheses in the posterior mandibles of five patients. Each patient had two prostheses, one supported by two implants and the other supported by one implant and one tooth. The results demonstrated no major difference in functional load magnitudes related to the support type. The distribution of load between the abutments was influenced more by the prosthesis geometry and implant placement than by the difference in load characteristics of tooth and implant. This conclusion, however, is limited to one implant connected to a tooth, because multiple implants form a considerably stiffer unit than do teeth. An increase in vertical load resulting from cantilever extensions on the prostheses was documented, both at bite fork measurements and during chewing. No substantial lateral bending was registered, probably because the flat occlusal surfaces and the presence of the opposing complete denture reduced lateral forces. PMID:9197098

Gunne, J; Rangert, B; Glantz, P O; Svensson, A

1997-01-01

188

Immunomodulation Stimulates the Innervation of Engineered Tooth Organ  

PubMed Central

The sensory innervation of the dental mesenchyme is essential for tooth function and protection. Sensory innervation of the dental pulp is mediated by axons originating from the trigeminal ganglia and is strictly regulated in time. Teeth can develop from cultured re-associations between dissociated dental epithelial and mesenchymal cells from Embryonic Day 14 mouse molars, after implantation under the skin of adult ICR mice. In these conditions however, the innervation of the dental mesenchyme did not occur spontaneously. In order to go further with this question, complementary experimental approaches were designed. Cultured cell re-associations were implanted together with trigeminal ganglia for one or two weeks. Although axonal growth was regularly observed extending from the trigeminal ganglia to all around the forming teeth, the presence of axons in the dental mesenchyme was detected in less than 2.5% of samples after two weeks, demonstrating a specific impairment of their entering the dental mesenchyme. In clinical context, immunosuppressive therapy using cyclosporin A was found to accelerate the innervation of transplanted tissues. Indeed, when cultured cell re-associations and trigeminal ganglia were co-implanted in cyclosporin A-treated ICR mice, nerve fibers were detected in the dental pulp, even reaching odontoblasts after one week. However, cyclosporin A shows multiple effects, including direct ones on nerve growth. To test whether there may be a direct functional relationship between immunomodulation and innervation, cell re-associations and trigeminal ganglia were co-implanted in immunocompromised Nude mice. In these conditions as well, the innervation of the dental mesenchyme was observed already after one week of implantation, but axons reached the odontoblast layer after two weeks only. This study demonstrated that immunodepression per se does stimulate the innervation of the dental mesenchyme. PMID:24465840

Kokten, Tunay; Becavin, Thibault; Keller, Laetitia; Weickert, Jean-Luc; Kuchler-Bopp, Sabine; Lesot, Herve

2014-01-01

189

Charcot-Marie-Tooth disease  

PubMed Central

Objectives: To determine the genetic distribution and the phenotypic correlation of an extensive series of patients with Charcot-Marie-Tooth disease in a geographically well-defined Mediterranean area. Methods: A thorough genetic screening, including most of the known genes involved in this disease, was performed and analyzed in this longitudinal descriptive study. Clinical data were analyzed and compared among the genetic subgroups. Results: Molecular diagnosis was accomplished in 365 of 438 patients (83.3%), with a higher success rate in demyelinating forms of the disease. The CMT1A duplication (PMP22 gene) was the most frequent genetic diagnosis (50.4%), followed by mutations in the GJB1 gene (15.3%), and in the GDAP1 gene (11.5%). Mutations in 13 other genes were identified, but were much less frequent. Sixteen novel mutations were detected and characterized phenotypically. Conclusions: The relatively high frequency of GDAP1 mutations, coupled with the scarceness of MFN2 mutations (1.1%) and the high proportion of recessive inheritance (11.6%) in this series exemplify the particularity of the genetic distribution of Charcot-Marie-Tooth disease in this region. PMID:24078732

Sivera, Rafael; Vilchez, Juan Jesus; Martinez-Rubio, Dolores; Chumillas, Maria Jose; Vazquez, Juan Francisco; Muelas, Nuria; Bataller, Luis; Millan, Jose Maria; Palau, Fancesc; Espinos, Carmen

2013-01-01

190

Tooth Time: MT AHEC/MORH  

E-print Network

1) Tooth decay is the most prevalent chronic disease affecting children 2) Oral disease impactsTooth Time: MT AHEC/MORH Elementary School Oral Health Screening Program #12;Oral Health in America as a plug for the February screenings #12;The Presentation Objectives: · Dental Decay and Gingivitis: what

Maxwell, Bruce D.

191

Addressing Tooth Decay in Head Start Children  

Microsoft Academic Search

Tooth decay is the most prevalent chronic disease of childhood. Oral health education and dental services are crucial to reducing the number of children afflicted with dental cavities. Due to limited access to preventative care, Head Start children are particularly vulnerable to tooth decay. This article outlines practical implications of a research study (Knowlden, Hill, Alles-White, & Cottrell, 2012\\/this issue)

Adam P. Knowlden; Lawrence F. Hill; Monica L. Alles-White; Randall R. Cottrell

2012-01-01

192

Addressing Tooth Decay in Head Start Children  

ERIC Educational Resources Information Center

Tooth decay is the most prevalent chronic disease of childhood. Oral health education and dental services are crucial to reducing the number of children afflicted with dental cavities. Due to limited access to preventative care, Head Start children are particularly vulnerable to tooth decay. This article outlines practical implications of a…

Knowlden, Adam P.; Hill, Lawrence F.; Alles-White, Monica L.; Cottrell, Randall R.

2012-01-01

193

ISS protocol for EPR tooth dosimetry  

Microsoft Academic Search

The accuracy in Electron Paramagneetic Resonance (EPR) dose reconstruction with tooth enamel is affected by sample preparation, dosimetric signal amplitude evaluation and unknown dose estimate. Worldwide efforts in the field of EPR dose reconstruction with tooth enamel are focused on the optimization of the three mentioned steps in dose assessment. In the present work, the protocol implemented at ISS in

S. Onori; D. Aragno; P. Fattibene; E. Petetti; M. C. Pressello

2000-01-01

194

Biologically Based Restorative Management of Tooth Wear  

PubMed Central

The prevalence and severity of tooth wear is increasing in industrialised nations. Yet, there is no high-level evidence to support or refute any therapeutic intervention. In the absence of such evidence, many currently prevailing management strategies for tooth wear may be failing in their duty of care to first and foremost improve the oral health of patients with this disease. This paper promotes biologically sound approaches to the management of tooth wear on the basis of current best evidence of the aetiology and clinical features of this disease. The relative risks and benefits of the varying approaches to managing tooth wear are discussed with reference to long-term follow-up studies. Using reference to ethical standards such as “The Daughter Test”, this paper presents case reports of patients with moderate-to-severe levels of tooth wear managed in line with these biologically sound principles. PMID:22315608

Kelleher, Martin G. D.; Bomfim, Deborah I.; Austin, Rupert S.

2012-01-01

195

Effects of tooth damage on spur gear vibrations  

NASA Astrophysics Data System (ADS)

The geared servomechanism is an important device used in many industrial applications for transferring power and motion. Over time, the meshing of gear teeth will lead to wear and damage. In this paper, the dynamics of a spur gear pair with damage to a single tooth will be instigated. Damage associated with the formation of a fillet crack and spalling will be simulated. The dynamic forces induced often result in a higher level of noise and vibration within the gear system. The prime direction of the present work is to study the effects of damage on the transient and steady-state vibration response of a spur gear pair. Simulation results indicate that damage significantly affects the response of the system and may accelerate tooth failure.

Richards, Donald A.; Pines, Darryll J.

2000-06-01

196

Cochlear Implants  

MedlinePLUS

... clinic for an evaluation. The implant team (otolaryngologist, audiologist, nurse, and others) will determine your candidacy for ... for the implant procedure. Hearing (audiologic) evaluation: The audiologist performs extensive hearing tests to find out how ...

197

Breast Implants  

MedlinePLUS

... Safety Data on Silicone Gel-Filled Breast Implants (Press Announcement) [ARCHIVED] Breast Implant Guidance for Industry (2006) Post Approval Studies Webpage Freedom of Information Requests Page Last Updated: 09/17/ ...

198

Cochlear Implants  

MedlinePLUS

A cochlear implant is a small, complex electronic device that can help to provide a sense of sound. People who are ... of-hearing can get help from them. The implant consists of two parts. One part sits on ...

199

A Retrospective Analysis of Ruptured Breast Implants  

PubMed Central

Background Rupture is an important complication of breast implants. Before cohesive gel silicone implants, rupture rates of both saline and silicone breast implants were over 10%. Through an analysis of ruptured implants, we can determine the various factors related to ruptured implants. Methods We performed a retrospective review of 72 implants that were removed for implant rupture between 2005 and 2014 at a single institution. The following data were collected: type of implants (saline or silicone), duration of implantation, type of implant shell, degree of capsular contracture, associated symptoms, cause of rupture, diagnostic tools, and management. Results Forty-five Saline implants and 27 silicone implants were used. Rupture was diagnosed at a mean of 5.6 and 12 years after insertion of saline and silicone implants, respectively. There was no association between shell type and risk of rupture. Spontaneous was the most common reason for the rupture. Rupture management was implant change (39 case), microfat graft (2 case), removal only (14 case), and follow-up loss (17 case). Conclusions Saline implants have a shorter average duration of rupture, but diagnosis is easier and safer, leading to fewer complications. Previous-generation silicone implants required frequent follow-up observation, and it is recommended that they be changed to a cohesive gel implant before hidden rupture occurs.

Baek, Woo Yeol; Lew, Dae Hyun

2014-01-01

200

Laser ultrasonic techniques for assessment of tooth structure  

NASA Astrophysics Data System (ADS)

Dental health care and research workers require a means of imaging the structures within teeth in vivo. For example, there is a need to image the margins of a restoration for the detection of poor bonding or voids between the restorative material and the dentin. With conventional x-ray techniques, it is difficult to detect cracks and to visualize interfaces between hard media. This due to the x-ray providing only a 2 dimensional projection of the internal structure (i.e. a silhouette). In addition, a high resolution imaging modality is needed to detect tooth decay in its early stages. If decay can be detected early enough, the process can be monitored and interventional procedures, such as fluoride washes and controlled diet, can be initiated which can help the tooth to re-mineralize itself. Currently employed x-ray imaging is incapable of detecting decay at a stage early enough to avoid invasive cavity preparation followed by a restoration with a synthetic material. Other clinical applications include the visualization of periodontal defects, the localization of intraosseous lesions, and determining the degree of osseointegration between a dental implant and the surrounding bone. A means of assessing the internal structure of the tooth based upon use of high frequency, highly localized ultrasound (acoustic waves) generated by a laser pulse is discussed. Optical interferometric detection of ultrasound provides a complementary technique with a very small detection footprint. Initial results using laser-based ultrasound for assessment of dental structures are presented. Discussion will center on the adaptability of this technique to clinical applications.

Blodgett, David W.; Baldwin, Kevin C.

2000-06-01

201

Ultrasonic assessment of tooth structure  

NASA Astrophysics Data System (ADS)

A means of assessing the internal structure of teeth based upon use of high frequency, highly localized ultrasound (acoustic waves) generated by a short laser pulse is discussed. Some key advantages of laser-generated ultrasound over more traditional contact transducer methods are that it is noncontact and nondestructive in nature and requires no special surface preparation. Optical interferometric detection of ultrasound provides a complementary nondestructive, noncontact technique with a very small detection footprint. This combination of techniques, termed laser-based ultrasonics, holds promise for future in-vivo diagnostics of tooth health. In this paper, initial results using laser-based ultrasound for assessment of dental structures are presented on an extracted human incisor. Results show the technique to be sensitive to the enamel/dentin, dentin/pulp, and dentin/cementum junctions as well as a region of dead tracts in the dentin.

Blodgett, David W.

2002-06-01

202

Spectroscopic investigations of carious tooth decay  

Microsoft Academic Search

We report on the elemental composition of healthy and infected part of human tooth using laser induced breakdown spectroscopy (LIBS). We have used prominent constituent transitions in laser-excited tooth to diagnose the state of the tooth. A nanosecond laser pulse (355nm, 5ns) was used as an ablating pulse and the sodium (3s2S–3p2P) at 588.99 and (3s2S–3p2P) at 589.99nm, strontium (5s21S–1s5P)

R. K. Thareja; A. K. Sharma; Shobha Shukla

2008-01-01

203

Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs  

PubMed Central

Background Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. Methodology/Principal Findings We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. Conclusions/Significance Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently evolved the highest known tooth replacement rates among archosaurs. PMID:23874921

Smith, Kathlyn M.; Fisher, Daniel C.; Wilson, Jeffrey A.

2013-01-01

204

Page 1 of 2 Traditional belief in "tooth worms" could  

E-print Network

believed in "tooth worms" had a reduced likelihood of extensive tooth decay. In addition, these children. They also gave questionnaires to parents, of whom 1716 answered a question on the main cause of tooth decay-fifths (39.8%) showed any signs of tooth decay--that is, one or more of their teeth were decayed, missing

Tam, Vincent W. L.

205

Biomaterials in Tooth Tissue Engineering: A Review  

PubMed Central

Biomaterials play a crucial role in the field of tissue engineering. They are utilized for fabricating frameworks known as scaffolds, matrices or constructs which are interconnected porous structures that establish a cellular microenvironment required for optimal tissue regeneration. Several natural and synthetic biomaterials have been utilized for fabrication of tissue engineering scaffolds. Amongst different biomaterials, polymers are the most extensively experimented and employed materials. They can be tailored to provide good interconnected porosity, large surface area, adequate mechanical strengths, varying surface characterization and different geometries required for tissue regeneration. A single type of material may however not meet all the requirements. Selection of two or more biomaterials, optimization of their physical, chemical and mechanical properties and advanced fabrication techniques are required to obtain scaffold designs intended for their final application. Current focus is aimed at designing biomaterials such that they will replicate the local extra cellular environment of the native organ and enable cell-cell and cell-scaffold interactions at micro level required for functional tissue regeneration. This article provides an insight into the different biomaterials available and the emerging use of nano engineering principles for the construction of bioactive scaffolds in tooth regeneration. PMID:24596804

Sharma, Sarang; Srivastava, Dhirendra; Grover, Shibani; Sharma, Vivek

2014-01-01

206

A longitudinal comparison of tooth whitening resulting from dentifrice use.  

PubMed

The effect of twice-daily brushing with one of three different dentifrices (Arm & Hammer Dental Care, Arm & Hammer Dental Care Extra Whitening, Crest) on stain removal and tooth whitening was examined in 115 volunteers over a period of 12 weeks. The facial surfaces of 12 anterior teeth were assessed for stain using a published, modified version of a standard stain index. Whiteness was measured on teeth 8 and 9 using a single Vita Lumin-Vaccum Shade Guide for consistency. At baseline, the mean facial stain scores were significantly higher (p < 0.05-0.01) for both Arm & Hammer dentifrices than for Crest. In addition, the tooth shades, as indicated by the stain guide, specifically the b* values representing yellowness, were quantified using a Minolta spectrophotometer. Arm & Hammer Dental Care Extra Whitening formula was found to be significantly better than Crest at removing naturally occurring extrinsic stain. The difference between Arm & Hammer Dental Care Extra Whitening and Crest became significant (p < 0.01) after two weeks of use, and remained intact during the balance of the study, achieving p values of 0.0002 for at least one of the three assessed parameters (total stain, proximal, and facial) at weeks 4 and 12. The study also found that Arm & Hammer Dental Care produced a significant increase in tooth whiteness by week 12, whereas Crest showed no such increase at any time during the study. These results suggest that the two Arm & Hammer Baking Soda products are more effective in reducing stain and increasing whiteness than the standard silica-based dentifrice. Their effectiveness is not related to abrasivity since they are less abrasive to tooth enamel than the silica-based product tested. PMID:10518865

Koertge, T E; Brooks, C N; Sarbin, A G; Powers, D; Gunsolley, J C

1998-01-01

207

[Fundamental and practical study for DNA analysis using tooth as a source of DNA].  

PubMed

Degree of degradation and the yield of DNA extracted from dental pulp tissues were examined on the tooth samples (n = 50) stored at room temperature and the method of DNA extraction from tooth hard tissues was also investigated. The DNA samples obtained were also applied to forensic odontological material examination including DNA fingerprinting using a probe Myo and VNTR (variable number of tandem repeat) analysis in D4S43 locus by PCR. The amount of DNA obtained from the dental pulp tissue of a single tooth varied approximately from 3 to 40 micrograms. In most cases, high molecular weight DNA was still present in samples stored at room temperature for at least 336 days. When the dental pulp tissue samples were less than 5 mg in weight, the amount DNA extracted was usually less than 10 micrograms, however when the samples were more than 5 mg in weight, the amount of DNA extracted was more than 10 micrograms. No correlation was observed between the storage period of the tooth samples and the DNA extraction ratio (the amount of extracted DNA weight, micrograms/pulp weight, mg). The efficiency of DNA extraction from tooth hard tissues was investigated under different conditions using 0.005 M and 0.5 M EDTA solutions for decalcification. DNA was efficiently extracted from the tooth samples which were decalcified for one week without changing the 0.5 M EDTA solution or by changing the solution once within a week. Rapid decalcification using formic acid buffer was not suitable for DNA extraction from tooth hard tissues. Southern blot hybridization of DNA samples extracted from pulp tissues using Myo probe gave multiple bands. Finger print patterns obtained from DNA recovered from dental pulp and tooth hard tissues samples were identical, however, the number of hybridizing bands obtained from tooth hard tissues was less than that obtained from blood and dental pulp tissues. The D4S43 typing using DNA recovered from blood stains, dental pulp tissues and tooth hard tissues of the same individuals was in agreement with each other and the 184bp fragment was efficiently amplified in all the samples tested. The DNA obtained from dental pulp tissues usually contains high molecular weight DNA and was suitable for multilocus probe and PCR analysis. However, the DNA obtained from tooth hard tissues was suitable only for PCR analysis. PMID:7723194

Hanaoka, Y; Inoue, M; Tsai, T H; Minaguchi, K

1995-02-01

208

Newer Technologies Find Tooth Decay Early  

MedlinePLUS

Newer Technologies Find Tooth Decay Early Digital Imaging Fiber-Optic Trans-Illumination (DIFOTI) Digital Imaging: DIAGNOdent Quantitative Light-Induced ... early damage. Now some dentists are using newer technologies. Do these devices really do a better job ...

209

Computer simulation of gear tooth manufacturing processes  

NASA Technical Reports Server (NTRS)

The use of computer graphics to simulate gear tooth manufacturing procedures is discussed. An analytical basis for the simulation is established for spur gears. The simulation itself, however, is developed not only for spur gears, but for straight bevel gears as well. The applications of the developed procedure extend from the development of finite element models of heretofore intractable geometrical forms, to exploring the fabrication of nonstandard tooth forms.

Mavriplis, Dimitri; Huston, Ronald L.

1990-01-01

210

Dental Implants  

MedlinePLUS Videos and Cool Tools

... create a structure for the face and their loss can shift the surrounding teeth, creating esthetic issues and bite problems. A lost tooth can also affect facial structures such as the jaw, muscles, jaw joints, and even the skin. If several ...

211

Clinical evaluation of a single-pass implantable electrode for all modes of pacing. The "Crown of Thorns" lead.  

PubMed

Physiological pacing was instituted in 17 patients (11 men and 6 women), mean age 67 years (range 33-77 years), using a variety of multiprogramable generators attached to a permanent single-pass dual chamber electrode. Eleven patients were paced in VAT mode (Cordis 208A or Siemens-Elema 625 generator), two patients in DVI mode (Intermedics Cyberlith IV generator) and four patients in DDD mode (Siemens-Elema 664/P33 or Telectronics Autima unit). Mean intracardiac P wave amplitude was 2.0 mV +/- 0.78/SD, range 0.7-3.6 mV. and mean atrial and ventricular pacing thresholds were 1.0 V and 0.5 V, respectively. Fourteen patients had completely successful A-V pacing during a follow-up period of 4-13 months (mean 7 +/- 2.7 months). Two failures were associated with malposition of the atrial crown and occurred exclusively with the Cordis 208A generator. In both patients generator replacement using a more sensitive unit (Siemens-Elema 625) resulted in successful VAT pacing for most of the time. Complete failure of A-V pacing occurred in only one patient who died from coronary artery disease after four months of follow-up. Thus, all of the remaining 16 patients achieved long-term (6 months) satisfactory physiological pacing using this new lead. We conclude that the "Crown of Thorns" electrode is a successful single-pass unipolar lead and can be used with all types of dual chamber generator for all modes of pacing. PMID:6189059

Wainwright, R; Crick, J; Sowton, E

1983-03-01

212

Implantable Microimagers  

PubMed Central

Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications.

Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun

2008-01-01

213

Comparison of the benefits of cochlear implantation versus contra-lateral routing of signal hearing aids in adult patients with single-sided deafness: study protocol for a prospective within-subject longitudinal trial  

PubMed Central

Background Individuals with a unilateral severe-to-profound hearing loss, or single-sided deafness, report difficulty with listening in many everyday situations despite having access to well-preserved acoustic hearing in one ear. The standard of care for single-sided deafness available on the UK National Health Service is a contra-lateral routing of signals hearing aid which transfers sounds from the impaired ear to the non-impaired ear. This hearing aid has been found to improve speech understanding in noise when the signal-to-noise ratio is more favourable at the impaired ear than the non-impaired ear. However, the indiscriminate routing of signals to a single ear can have detrimental effects when interfering sounds are located on the side of the impaired ear. Recent published evidence has suggested that cochlear implantation in individuals with a single-sided deafness can restore access to the binaural cues which underpin the ability to localise sounds and segregate speech from other interfering sounds. Methods/Design The current trial was designed to assess the efficacy of cochlear implantation compared to a contra-lateral routing of signals hearing aid in restoring binaural hearing in adults with acquired single-sided deafness. Patients are assessed at baseline and after receiving a contra-lateral routing of signals hearing aid. A cochlear implant is then provided to those patients who do not receive sufficient benefit from the hearing aid. This within-subject longitudinal design reflects the expected care pathway should cochlear implantation be provided for single-sided deafness on the UK National Health Service. The primary endpoints are measures of binaural hearing at baseline, after provision of a contra-lateral routing of signals hearing aid, and after cochlear implantation. Binaural hearing is assessed in terms of the accuracy with which sounds are localised and speech is perceived in background noise. The trial is also designed to measure the impact of the interventions on hearing- and health-related quality of life. Discussion This multi-centre trial was designed to provide evidence for the efficacy of cochlear implantation compared to the contra-lateral routing of signals. A purpose-built sound presentation system and established measurement techniques will provide reliable and precise measures of binaural hearing. Trial registration Current Controlled Trials http://www.controlled-trials.com/ISRCTN33301739 (05/JUL/2013) PMID:25152694

2014-01-01

214

Patterns in ritual tooth avulsion at Roonka.  

PubMed

Tooth avulsion is the intentional removal of one or more teeth for ritual or aesthetic reasons, or to denote group affiliation. Typically the maxillary incisors are the teeth most often selected for removal. Previous authors have discussed the presence of tooth avulsions in several individuals recovered from Roonka, but those papers did not examine any patterns in those removals that might be present. Analysis of the tooth avulsions at Roonka reveals a change in the practice over time, with the older burials from phase II typically showing removal of both maxillary central incisors with a left side bias when only one tooth is removed, and the more recent phase III burials showing only one incisor avulsed and a right side bias for removal. Frequencies in the practice also changed over time, with avulsions being much more common in the older phase II burials. Historical evidence suggests that any particular regional or social group would have its own particular pattern of tooth avulsion, so these changes in tooth avulsions at Roonka suggest that the site was either used by multiple groups of people for burials, or that there was significant cultural change during the occupation of the site. PMID:24827419

Durband, Arthur C; Littleton, Judith; Walshe, Keryn

2014-08-01

215

Present and future technologies of tooth whitening.  

PubMed

Dental stains can be broadly classified as intrinsic or extrinsic. Intrinsic stains are a result of defects in tooth development, fluorosis, or acquired through the use of tetracycline. Extrinsic stains are localized mainly in the pellicle and are generated by the reaction between sugars and amino acids or acquired from the retention of exogenous chromophores in the pellicle. Three clinical methods are currently used for measuring stain removal and tooth whitening in the development of new whitening technologies: Lobene Stain Index, Shade Guide Color Change, and Minolta ChromaMeter. Professional tooth whitening products rely on proven technologies--35% hydrogen peroxide for in-office power bleaching or 10% to 15% carbamide peroxide for at-home bleaching--to reduce intrinsic stain and change the inherent tooth color. Over-the-counter tooth whitening products use a combination of surfactants, abrasives, anticalculus agents, and low levels of hydrogen peroxide to reduce extrinsic stain and help maintain tooth whiteness after professional treatment. Future technologies for whitening teeth could involve the use of activating agents to enhance the performance of hydrogen peroxide and natural enzymes. PMID:11908346

Viscio, D; Gaffar, A; Fakhry-Smith, S; Xu, T

2000-01-01

216

Determination of lattice site locations of erbium ions implanted into LiNbO 3 single crystals after annealing at moderate and high temperature  

NASA Astrophysics Data System (ADS)

X-ray absorption spectroscopy (XAS) has been applied to study the local structure around erbium ions implanted at 300 keV (2×10 16 Er+ ions/cm2) in LiNbO 3 Y-cut single crystals annealed for 20 h in air at 500 and 1100 °C, respectively. For both samples, the data clearly reveal that Er 3+ has neither formed metallic aggregates in the matrix nor precipitated in the form of the oxide. The data for the sample annealed at 500 °C for 20 h show that Er 3+ is probably incorporated at the Nb site of the reconstructed LiNbO 3 host lattice, or more precisely surrounded by a similar local atomic arrangement. For the sample annealed at 1100 °C for 20 h, the XAS results show that Er 3+ is probably located on both Li and Nb sites of the LiNbO 3 host, but there remain puzzling points. These can be understood from wide angle X-ray spectroscopy (WAXS) data, which indicate the formation of a phase similar to ErVO 3, a perovskite-type compound where the trivalent vanadium is replaced by a mixture of lithium and niobium ions. This result then is in excellent agreement with the ionic radii values of lithium and of niobium ions (0.69 and 0.68 Å, respectively), which are also nearly equal to that of trivalent vanadium (0.68 Å).

Mignotte, C.

2001-12-01

217

Tooth Sensitivity in Fluorotic Teeth  

PubMed Central

Objectives: The aim of this study was to compare the demographic and clinical features of tooth sensitivity (TS) in subjects with and without fluorosis. Methods: A total of 2249 subjects (378 subjects with fluorosis and 1871 subjects without fluorosis) were examined for TS during a study period of one year and TS was determined in 122 subjects. The level of TS was evaluated on a visual analogue scale (VAS). The sensitivity evaluation was made by applying tactile and cold air stimuli. In teeth sensitive to any stimuli, the plaque index (PI), gingival index (GI), gingival recession (GR) and periodontal pocket depth (PPD) were recorded. Fluorosis was assessed using the Dean Index. Results: One hundred and twenty-two participants were found to have TS (5.42%). The frequency of TS in subjects with fluorosis was 9.26%, while the frequency of TS in subjects without fluorosis was 4.65%. There was a statistically significant difference between the groups in terms of TS frequency (P=0.0003). In contrast, there were no significant differences between the groups for periodontal parameters except PI. Conclusions: The results of the study showed that the subjects with fluorosis may have been suffering from TS more than the subjects with normal dentition. Further studies are necessary to determine the factors that contribute to sensitivity of teeth with fluorosis. PMID:21769268

Tonguc, Mine Ozturk; Ozat, Yener; Sert, Tugba; Sonmez, Yonca; Kirzioglu, F. Yesim

2011-01-01

218

Charcot-Marie-Tooth disease.  

PubMed

The family of hereditary peripheral neuropathies that makes up Charcot-Marie-Tooth disease (CMT) comprises some of the most common neuromuscular disorders. Over the past decade, understanding of the molecular basis of CMT has increased enormously. In addition, the neurophysiologic deficits and clinical problems associated with CMT are more clearly delineated, and the precise genetic cause of many types of CMT has now been determined. Advances in molecular biology and genetic manipulation techniques have allowed the development of animal models of some of these CMT types, allowing more productive scientific exploration of possible treatments. Recent treatment advances that have been effective in animal models include oral supplementation with curcumin and vitamin C (ascorbic acid), and the use of onapristone, a progesterone antagonist. Human trials with vitamin C are currently in progress. While ongoing molecular genetic research continues to identify more of the mutant genes and proteins that cause the various disease subtypes, clinical research should continue to focus on developing pharmaceutical and rehabilitative therapies to ameliorate nerve degeneration and ultimately improve function for patients with CMT. These patients optimally should be managed in a comprehensive, multidisciplinary setting involving neurologists, physiatrists, orthopedic surgeons, physical and occupational therapists, and orthotists. Treatment should be aimed at maximizing independence and quality of life. PMID:18334132

Carter, Gregory T; Weiss, Michael D; Han, Jay J; Chance, Phillip F; England, John D

2008-03-01

219

Ion Implantation  

NASA Astrophysics Data System (ADS)

In this tutorial we describe the basic principles of the ion implantation technique and we demonstrate that emission Mössbauer spectroscopy is an extremely powerful technique to investigate the atomic and electronic configuration around implanted atoms. The physics of dilute atoms in materials, the final lattice sites and their chemical state as well as diffusion phenomena can be studied. We focus on the latest developments of implantation Mössbauer spectroscopy, where three accelerator facilities, i.e., Hahn-Meitner Institute Berlin, ISOLDE-CERN and RIKEN, have intensively been used for materials research in in-beam and on-line Mössbauer experiments immediately after implantation of the nuclear probes.

Langouche, G.; Yoshida, Y.

220

Endodontic implants  

PubMed Central

Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities.

Yadav, Rakesh K.; Tikku, A. P.; Chandra, Anil; Wadhwani, K. K.; Ashutosh kr; Singh, Mayank

2014-01-01

221

Peri-implantitis. Part 3: Current modes of management.  

PubMed

Peri-implantitis is an inflammatory condition fuelled by the presence of bacteria on the implant surface. As such, in a similar manner to periodontal disease management, the removal of biofilm from the implant surface should result in regression of the disease process. The optimal manner with which this is achieved has yet to be realised. This may be unsurprising due to the relative surface complexity of the implant surface when compared to natural tooth root. Other management strategies include surface decontamination, the removal of implant threads known as implantoplasty, and in severe cases the need to explant. Favourable defects can be reconstructed utilising guided bone regeneration techniques. The current review appraises some of the techniques for the management of peri-implantitis. PMID:25303581

Alani, A; Bishop, K

2014-10-10

222

Oxygen implanter for simox  

Microsoft Academic Search

Interest in silicon or) insulator (SOI) technology has led to the development of several alternatives to silicon on sapphire. One of the most promising techniques makes use of an ion implanter to form a buried oxide layer directly in the silicon substrate. To have useful single crystalline silicon on top of the oxide layer, it is necessary to do the

M. Guerra; V. Benveniste; G. Ryding; D. H. Douglas-Hamilton; M. Reed; G. Gagne; A. Armstrong; M. Mack

1985-01-01

223

Immediate implants in anterior maxillary arch  

PubMed Central

Aim: The aim of the study was to evaluate the osseo-integration and soft tissue status of the endosseous implants placed in immediate extraction socket. Methodology: Seven patients (4 males and 3 females) aged 20-30 years were selected for the study. Nine implants were placed in seven patients in the maxillary arch. All the patients were clinically ?nd thoroughly examined. Under local anesthesia, the indicated tooth was extracted. The extracted socket was prepared using standard drills with palatal wall as guide. The longest and widest implants were placed (Hi-Tec Implants). All implants showed good primary stability. The implants used in the study were tapered design endosseous implants with Threaded implants (TI) unit plasma-sprayed surface. Surgical re-entry (secondary surgery) was performed to remove the healing cap after 6 months for supra crestal fabrication. All patients were reviewed periodically at 3rd and 6th month interval and the following clinical parameters including modified plaque index (mPlI), modified bleeding index (mBI), probing depth (PD), attachment level (AL), and distance between the implant shoulder and mucosal margin (DIM), distance between the implant shoulder and first bone-implant contact, and Clinical Mobility Index were recorded. The results were computed and subjected to statistical evaluation. Results: The mPlI, mBI, PD, AL, and DIM were evaluated around the implants at baseline, 3rd and 6th month intervals and analyzed statistically by Friedman T-test. The results of the above were shown to be statistically non-significant. The distance between the implant shoulder and first bone implant contact was evaluated around the implants at base line, 3rd and 6th month intervals. The results proved to be statistically significant (0.01) implying that there was a bone apposition around the implants. Conclusion: During the course of the study, soft tissue status around implants was found to be healthy. Osseointegration as assessed by clinical and radiographic findings was found to be sound. PMID:24678203

Anitha, K.; Kumar, S. Senthil; Babu, M. R. Ramesh; Candamourty, Ramesh; Thirumurugan

2014-01-01

224

Multiferroic nanoparticulate thin film composites by Co implantation of ferroelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal targets  

NASA Astrophysics Data System (ADS)

Two-phase magnetostrictive-piezoelectric thin film composites are key materials to the development of a range of potentially disruptive magnetoelectric technologies, such as electrical-writing magnetic-reading random access memories. However, multiferroic thin film composites prepared so far show neither magnetoelectric switching nor magnetoelectric responses comparable to those of related bulk ceramic materials and cermets. Here we show that ion implantation of magnetic species into ferroelectric single crystal targets can be an effective alternative means of obtaining nanoparticulate thin film composites of this type. Concept is proved by the implantation of Co into a Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal with ultrahigh piezoelectricity. Formation of an ensemble of ferromagnetic nanoparticles embedded in an amorphized layer within the ferroelectric crystal is clearly shown.

Torres, María; Ricote, Jesús; Amorín, Harvey; Jaafar, Miriam; Holgado, Susana; Piqueras, Juan; Asenjo, Agustina; García-Hernández, Mar; Algueró, Miguel

2011-12-01

225

Adhesion of Dental Materials to Tooth Structure  

NASA Astrophysics Data System (ADS)

The understanding and proper application of the principles of adhesion has brought forth a new paradigm in the realm of esthetic dentistry. Modern restorative tooth procedures can now conserve the remaining tooth-structure and also provide for the strengthening of the tooth. Adhesive restorative techniques call for the application and curing of the dental adhesive at the interface between the tooth tissue and the filling material. Hence the success of the restoration depends largely on the integrity of this interface. The mechanism of adhesion of the bonding materials to the dental hard tissue will be discussed in this paper. There are four main steps that occur during the application of the dental adhesive to the oral hard tissues: 1) The first step is the creation of a microstructure in the tooth enamel or dentin by means of an acidic material. This can be through the application of a separate etchant or can be accomplished in situ by the adhesive/primer. This agent has to be effective in removing or modifying the proteinaceous “smear” layer, which would otherwise act as a weak boundary layer on the surface to be bonded. 2) The primer/adhesive must then be able to wet and penetrate the microstructure created in the tooth. Since the surface energies of etched enamel and that of etched dentin are different finding one material to prime both types of dental tissues can be quite challenging. 3) The ionomer types of materials, particularly those that are carboxylate ion-containing, can chemically bond with the calcium ions of the hydroxyapatite mineral. 4) Polymerization in situ allows for micromechanical interlocking of the adhesive. The importance of having the right mechanical properties of the cured adhesive layer and its role in absorbing and dissipating stresses encountered by a restored tooth will also be discussed.

Mitra, Sumita B.

2000-03-01

226

Direct cord implantation in brachial plexus avulsions: revised technique using a single stage combined anterior (first) posterior (second) approach and end-to-side side-to-side grafting neurorrhaphy  

Microsoft Academic Search

BACKGROUND: The superiority of a single stage combined anterior (first) posterior (second) approach and end-to-side side-to-side grafting neurorrhaphy in direct cord implantation was investigated as to providing adequate exposure to both the cervical cord and the brachial plexus, as to causing less tissue damage and as to being more extensible than current surgical approaches. METHODS: The front and back of

Sherif M Amr; Ahmad M Essam; Ahmad M Kholeif; Ashraf N Moharram; Rashed ER El-Sadek

2009-01-01

227

Is Dual-Chamber Programming Inferior to Single-Chamber Programming in an Implantable Cardioverter-Defibrillator? Results of the INTRINSIC RV (Inhibition of Unnecessary RV Pacing With AVSH in ICDs) Study  

Microsoft Academic Search

Background—The INTRINSIC RV (Inhibition of Unnecessary RV Pacing with AVSH in ICDs) study tested the hypothesis that dual-chamber rate-responsive (DDDR) with atrioventricular search hysteresis (AVSH) 60-130 programming is not inferior to single-chamber (VVI)-40 programming in an implantable cardioverter defibrillator with respect to all-cause mortality and heart failure hospitalizations using an equivalence margin of 5%. Methods and Results—At 108 centers, 1530

Brian Olshansky; John D. Day; Stephen Moore; Lawrence Gering; Murray Rosenbaum; Maureen McGuire; Scott Brown; Darin R. Lerew

228

Guided implant surgery with placement of a presurgical CAD/CAM patient-specific abutment and provisional in the esthetic zone.  

PubMed

Parallel use of implant treatment planning software and cone-beam computed tomography (CBCT) can, using certain criteria, consolidate steps and streamline tooth replacement strategies. The authors describe such a case in the esthetic zone whereby flapless extraction and immediate implant placement using CT-guided surgery were performed simultaneously, with placement of a computer-aided design/computer-aided manufactured (CAD/CAM) patient-specific abutment and non-occlusal function provisional in a single visit (supporting the "one-abutment, one-time" concept). An over-retained primary cuspid in a periodontally healthy woman with well-controlled type-2 diabetes was replaced with an implant and CAD/CAM patient-specific abutment in the No. 11 position. A necessary implant-axis angle correction was customized using digital information from a CBCT scan and implant treatment planning software, without the need for site development or a conventional impression. This data integration and streamlined workflow enabled fabrication of a CAD/CAM patient-specific abutment before surgical treatment. The abutment remained in place from implant surgery to the prosthetic phase, with minimal soft-tissue changes, enabling preservation of pink esthetics and expediting treatment. The result was a preserved emergence profile in the presence of high esthetic demands. However, due to slight post-extraction soft-tissue changes, digital reformatting of the abutment was required when the final crown was fabricated, thus limiting the disruption of the biologic width to a one-time occurrence. The importance of case selection for this treatment protocol in the esthetic zone cannot be overemphasized. A thick crestal dentoalveolar bone phenotype (> 1 mm, approaching 2 mm in this case), broad zone of attached and keratinized gingiva (3 mm to 4 mm in this case), adequate peri-implant soft-tissue thickness (> 1 mm in this case), and high primary implant stability (ISQ = 80 in this case) were all critical factors influencing outcome. PMID:25198877

Mandelaris, George A; Vlk, Scott D

2014-01-01

229

Conversion of an existing metal ceramic crown to an interim restoration and nonfunctional loading of a single implant in the maxillary esthetic zone: A clinical report.  

PubMed

Implant placement and immediate placement of an interim restoration can be a safe therapeutic approach with high survival rates. The technique is often used in the anterior esthetic area because of the better preservation of the periimplant soft tissue contours. Traditionally this procedure involves the fabrication of an acrylic resin implant-supported interim restoration. This clinical report describes the modification of an existing metal ceramic crown to be used as an implant-supported interim restoration for immediate nonfunctional loading to achieve an improved esthetic result and optimal support of the adjacent soft tissues. PMID:24231435

Michalakis, Konstantinos; Kalpidis, Christos D R; Hirayama, Hiroshi

2014-01-01

230

Small tooth sizes in a nineteenth century South Carolina plantation slave series.  

PubMed

Sub-Saharan African (and derived) populations typically exhibit larger mean tooth crown diameters than whites in spite of considerable population variability. We report on a 19th century series of American black slaves from a single cemetery near Charleston, South Carolina, that possessed notably smaller crown sizes. Analysis identifies a characteristic set of differences compared to caucasians, including retention of large maxillary lateral incisors and disproportionately large premolars and molars. Regression of principal components scores (derived from the mesiodistal diameters) on the sum of all diameters (used here as a measure of overall tooth mass) confirms a basic ethnic difference between black and white odontometrics: significantly more of the tooth mass is apportioned to the cheek teeth (premolars, molars) in blacks than whites. The difference (expressed as residuals from linear regression on tooth mass) holds for the several groups assessed here despite considerable intergroup variability in tooth sizes. Potential explanations for the notably small diameters of this plantation series are speculative, but may involve kin-based divergences and/or reflect the natural intergroup differences extant in the African slave sources. PMID:2648862

Harris, E F; Rathbun, T A

1989-03-01

231

Treatment planning: implant-supported partial overdentures.  

PubMed

When multiple anterior teeth are missing, many options of replacement are available. Traditionally, the choice was between a fixed or removable prostheses. Today, with the predictability of dental implants, the options of tooth replacement range from removable partial dentures to implant-supported fixed prostheses. The choice of which restoration that will best provide occlusion and esthetics depends on multiple factors including the number and location of missing teeth, the residual ridge form in relation to the replacement teeth, the relationship of the maxillary and mandibular anterior teeth, the condition of teeth adjacent to the edentulous span, the amount of bone available for implant placement, the patients "smile line" and display of teeth, lip support, and financial constraints. When there is minimal loss of the ridge contour, restorations that emerge from the ridge are the most functional and esthetic restorations, adhesive-type fixed partial dentures, conventional fixed partial dentures, and implant-supported restorations can be indicated with the choice of restoration dependent on a risk benefit and cost benefit analysis. When there is a loss of ridge contour due to residual ridge resorption or trauma, the decision becomes more complex as not only does the tooth structure need to be replaced, the ridge form also has to be replaced. (Figures 1 and 2). This can be assessed clinically as illustrated by Figures 1 and 2 where a dis crepancy in arch form and ridge form in relation to the adjacent teeth and/or opposing arch can be observed. Other considerations are lip support and display of the teeth when smiling. This article presents a case and rationale for implant-supported par tial overdentures. Many authors have written on the merits of com plete overdentures. The complete overdenture has proven to be an improvement over conventional complete prostheses with respect to chewing efficiency, patient comfort and satisfaction. In partial edentulism, the implant-supported overdenture has several advantages, some in common with a removable partial denture. PMID:15915882

Chee, Winston W L

2005-04-01

232

Simplifying fixed implant dental prosthetics.  

PubMed

Through following the FPPD protocol for multiple adjacent implants, and delivering final abutments, picking up the metal framework, and delivering provisionals, many benefits are gained. The benefits of following the FPPD protocol are as follows: The restorative dentist is trying-in and delivering the final abutments in one visit as opposed to removing them and placing them multiple times. This requires less chair time and time for the patient. It also reduces the mechanical stress on the abutment screw and implant body due to the elimination of multiple try-in appointments. When the metal framework is tried-in and verified for fit, the restorative dentist has the opportunity check the retention, check the margins, and make any corrections that might be needed. The abutments will be staying in the mouth when the framework is picked up. This metal try-in allows for a verification of the bite to be given to the dental lab. The delivery of provisionals manufactured by the dental laboratory offers many advantages in the FPPD technique. The patient has a form of tooth much earlier in the traditional appointment sequence. The patient can now offer feedback to the doctor and laboratory for fabrication of the permanent prosthesis with regards to shape and color. The laboratory-fabricated provisionals offer progressive loading to the implants through having a reduced occlusion yet allowing food to stimulate the implants. Overall, the FPPD technique offers shorter appointment times, more rapid delivery of fixed supported teeth, improved doctor-technician communication, and less mechanical wear on the implant parts. PMID:21306074

Tischler, Michael

2011-01-01

233

The Ontogeny of Tooth Succession in Lacerta vivipara Jacquin (1787)  

Microsoft Academic Search

Edmund (1960) has shown that in the dentitions of almost all non-mammalian vertebrates, teeth are replaced in waves which regularly sweep through alternate tooth positions. He explained the ontogeny of these patterns of tooth replacement in terms of biological units called Zahnreihen whose existence has been accepted by nearly all workers studying tooth replacement. In the present paper it is

J. W. Osborn

1971-01-01

234

REVIEW ARTICLE Fibroblast growth factor signaling in mammalian tooth  

E-print Network

in tooth number, morphology or enamel structure. The parallel roles of FGF signaling in mouse and humanREVIEW ARTICLE Fibroblast growth factor signaling in mammalian tooth development Chun-Ying Li · Jan In this review, we discuss the central role of fibroblast growth factor (FGF) signaling in mammalian tooth

Klein, Ophir

235

The Importance of Tooth Decay Prevention in Children under Three  

ERIC Educational Resources Information Center

Tooth decay and tooth loss was once the norm but public health interventions have led to major improvements for most people. Nevertheless, not all children have benefited. Dental disease in young children is unacceptably high. Tooth decay is preventable. Early childhood educators are often the first to notice the problem. Professional…

Milgrom, Peter; Huebner, Colleen; Chi, Donald

2010-01-01

236

The mystery of declining tooth decay  

Microsoft Academic Search

Large temporal reductions in tooth decay, which cannot be attributed to fluoridation, have been observed in both unfluoridated and fluoridated areas of at least eight developed countries over the past thirty years. It is now time for a scientific re-examination of the alleged enormous benefits of fluoridation.

Mark Diesendorf

1986-01-01

237

Healthy teeth can last a lifetime! Tooth  

Microsoft Academic Search

decay and loss from oral diseases lead to costly dental work and dentures, was once accepted as a natural part of aging. Today more adults than ever are keeping their teeth well into their advanced years, presenting challenges for long-term and community caregivers. In spite of improvements in oral health, the elderly who are disadvantaged suffer severe tooth destruction and

Mary Kaplan; Donna Jacobi; Terry Dolan

238

Computed tomography to quantify tooth abrasion  

NASA Astrophysics Data System (ADS)

Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

2010-09-01

239

The art and science of tooth whitening.  

PubMed

Although tooth whitening is one of the most popular dental procedures, it is also one of the least understood. We are still unclear as to its mechanism of action. There is little data as to the effects of both concentration and dose on outcome. The techniques for measuring color change have been brought into question. The cause(s) of sensitivity and the effects of long-term exposure to hydrogen peroxide are not clear. The issue of rebound in color has not been well examined, and issues related to maintenance of the whitening effect are also poorly understood. The immediate placement of composite resin on bleached teeth has been controversial. According to a study evaluating the shear bond strength of composite restorations placed on bleached and nonbleached teeth, there was no statistically significant difference when the composites were placed at 24 hours, 48 hours, four days, or six days. A different study, which evaluated the effects of take-home bleaching systems on enamel surfaces, suggests that a period of four days must elapse before bonding to a tooth bleached with a peroxide material, while no delay is necessary for a non-peroxide-based bleaching system. Most recently, there has been a push to find ways to accelerate and improve the delivery of the whitening process. These include the application of a number of different light sources believed to accelerate the breakdown of peroxide and thus speed up the whitening process. However, the research in this area has been controversial, with publications having quite different conclusions as to the efficacy of light-activated bleaching. Finally, the issues of adverse events and possible side effects were reviewed. The toxicological side effects of tooth bleaching systems seem to be minimal. However, tooth sensitivity can be quite significant. Although its causes are poorly understood, tooth sensitivity is most often seen as the result of tooth dehydration. So while patient demand for tooth whitening is at an all-time high, and dentists have more options for treatment, it's important that dentists evaluate which of these options is most ideal for their patients, factoring in the patients' cost and time issues, as well as sensitivity to the procedure. PMID:15828604

Kugel, Gerard; Ferreira, Susana

2005-01-01

240

A comparison of single-suture and double-suture incision closures in seaward-migrating juvenile Chinook salmon implanted with acoustic transmitters: implications for research in river basins containing hydropower structures  

SciTech Connect

Reductions in the size of acoustic transmitters implanted in migrating juvenile salmonids have resulted in the ability to make shorter incisions that may warrant using only a single suture for closure. However, it is not known if one suture will sufficiently hold the incision closed, particularly when outward pressure is placed on the surgical site such as when migrating fish experience pressure changes associated with passage at hydroelectric dams. The objective of this research was to evaluate the effectiveness of single-suture incision closures on juvenile Chinook salmon (Oncorhynchus tshawytscha). Juvenile Chinook salmon were surgically implanted with a 2012 Juvenile Salmon Acoustic Telemetry System (JSATS) transmitter (0.30 g) and a passive integrated transponder tag (0.10 g) and incisions were closed with either one suture or two sutures. Mortality and tag retention were monitored and fish were examined after 7 and 14 days to evaluate tissue responses. In a separate experiment, surgically implanted fish were exposed to simulated turbine passage and then examined for expulsion of transmitters, expulsion of viscera through the incision, and mortal injury. With incisions closed using a single suture, there was no mortality or tag loss and similar or reduced tissue reaction compared to incisions closed with two sutures. Further, surgery time was significantly reduced when one suture was used, which leads to less handling and reduced stress. No tags were expelled during pressure scenarios and expulsion of viscera only occurred in two non-mortally injured fish (5%) with single sutures that were also exposed to very high pressure changes. No viscera expulsion was present in fish exposed to pressure scenarios likely representative of hydroturbine passage at many Columbia River dams (e.g. <2.7 ratio of pressure change; an acclimation pressure of 146.2 absolute kpa and a lowest exposure pressure of ~ 53.3 absolute kpa). Based on these results, we recommend the use of a single suture for surgical implantation of transmitters with incisions that are approximately 5 1/2 mm long after tag insertion.

Brown, Richard S.; Deters, Katherine A.; Cook, Katrina V.; Eppard, M. B.

2013-07-15

241

Generation of a crowned pinion tooth surface by a plane  

NASA Technical Reports Server (NTRS)

The topology of a crowned spur pinion tooth surface that reduces the level of transmission errors due to misalignment is described. The geometry of the modified pinion tooth surface and of the regular involute gear tooth surface is discussed. The tooth contact analysis between the meshing surfaces is also described. Generating a modified pinion tooth surface by a plane whose motion is controlled by a 5-degree-of-freedom system is investigated. The numerical results included indicate that the transmission error remains low as the gears are misaligned.

Litvin, F. L.; Zhang, J.; Handschuh, R. F.

1988-01-01

242

Detecting Inter-Cusp and Inter-Tooth Wear Patterns in Rhinocerotids  

PubMed Central

Extant rhinos are the largest extant herbivores exhibiting dietary specialisations for both browse and grass. However, the adaptive value of the wear-induced tooth morphology in rhinos has not been widely studied, and data on individual cusp and tooth positions have rarely been published. We evaluated upper cheek dentition of browsing Diceros bicornis and Rhinoceros sondaicus, mixed-feeding R. unicornis and grazing Ceratotherium simum using an extended mesowear method adapted for rhinos. We included single cusp scoring (EM(R)-S) to investigate inter-cusp and inter-tooth wear patterns. In accordance with previous reports, general mesowear patterns in D. bicornis and R. sondaicus were attrition-dominated and C. simum abrasion-dominated, reflecting their respective diets. Mesowear patterns for R. unicornis were more attrition-dominated than anticipated by the grass-dominated diet, which may indicate a low intake of environmental abrasives. EM(R)-S increased differentiation power compared to classical mesowear, with significant inter-cusp and inter-tooth differences detected. In D. bicornis, the anterior cusp was consistently more abrasion-dominated than the posterior. Wear differences in cusp position may relate to morphological adaptations to dietary regimes. Heterogeneous occlusal surfaces may facilitate the comminution of heterogeneous browse, whereas uniform, broad grinding surfaces may enhance the comminution of physically more homogeneous grass. A negative tooth wear gradient was found in D. bicornis, R. sondaicus and R. unicornis, with wear patterns becoming less abrasion-dominated from premolars to molars. No such gradients were evident in C. simum which displayed a uniform wear pattern. In browsers, premolars may be exposed to higher relative grit loads, which may result in the development of wear gradients. The second premolar may also have a role in food cropping. In grazers, high absolute amounts of ingested abrasives may override other signals, leading to a uniform wear pattern and dental function along the tooth row, which could relate to the observed evolution towards homodonty. PMID:24312507

Taylor, Lucy A.; Kaiser, Thomas M.; Schwitzer, Christoph; Muller, Dennis W. H.; Codron, Daryl; Clauss, Marcus; Schulz, Ellen

2013-01-01

243

Detecting inter-cusp and inter-tooth wear patterns in rhinocerotids.  

PubMed

Extant rhinos are the largest extant herbivores exhibiting dietary specialisations for both browse and grass. However, the adaptive value of the wear-induced tooth morphology in rhinos has not been widely studied, and data on individual cusp and tooth positions have rarely been published. We evaluated upper cheek dentition of browsing Diceros bicornis and Rhinoceros sondaicus, mixed-feeding R. unicornis and grazing Ceratotherium simum using an extended mesowear method adapted for rhinos. We included single cusp scoring (EM(R)-S) to investigate inter-cusp and inter-tooth wear patterns. In accordance with previous reports, general mesowear patterns in D. bicornis and R. sondaicus were attrition-dominated and C. simum abrasion-dominated, reflecting their respective diets. Mesowear patterns for R. unicornis were more attrition-dominated than anticipated by the grass-dominated diet, which may indicate a low intake of environmental abrasives. EM(R)-S increased differentiation power compared to classical mesowear, with significant inter-cusp and inter-tooth differences detected. In D. bicornis, the anterior cusp was consistently more abrasion-dominated than the posterior. Wear differences in cusp position may relate to morphological adaptations to dietary regimes. Heterogeneous occlusal surfaces may facilitate the comminution of heterogeneous browse, whereas uniform, broad grinding surfaces may enhance the comminution of physically more homogeneous grass. A negative tooth wear gradient was found in D. bicornis, R. sondaicus and R. unicornis, with wear patterns becoming less abrasion-dominated from premolars to molars. No such gradients were evident in C. simum which displayed a uniform wear pattern. In browsers, premolars may be exposed to higher relative grit loads, which may result in the development of wear gradients. The second premolar may also have a role in food cropping. In grazers, high absolute amounts of ingested abrasives may override other signals, leading to a uniform wear pattern and dental function along the tooth row, which could relate to the observed evolution towards homodonty. PMID:24312507

Taylor, Lucy A; Kaiser, Thomas M; Schwitzer, Christoph; Müller, Dennis W H; Codron, Daryl; Clauss, Marcus; Schulz, Ellen

2013-01-01

244

Ion Implant  

NSDL National Science Digital Library

This website includes an animation which illustrates the ion implant process. Objective: Name the three common dopants used in implantation processes and explain the process of generating an ion beam from source to wafer. You can find this animation under the heading "Process & Equipment III." This simulation is from Module 026 of the Process & Equipment III Cluster of the MATEC Module Library (MML). To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey

2012-10-04

245

Epidemiology and Risk Factors of Tooth Loss among Iranian Adults: Findings from a Large Community-Based Study  

PubMed Central

Objectives. To investigate the prevalence of tooth loss and different prosthetic rehabilitations among Iranian adults, as well as the potential determinants of tooth loss. Methods. In a cross-sectional community-based study conducted among 8094 Iranian adults living in Isfahan province, a self-administered questionnaire was used to assess epidemiologic features of tooth loss. Results. Thirty-two percent of subjects had all their teeth, 58.6% had lost less than 6, and 7.2% of participants had lost more than 6 teeth. One hundred and sixty-nine individuals (2.2%) were edentulous. Among participants, 2.3% had single jaw removable partial denture, 3.6% had complete removable denture in both jaws, and 4.6% had fixed prosthesis. Others reported no prosthetic rehabilitation (89.5%). In the age subgroup analysis (?35 and >35 years old) tooth loss was more prevalent among men than women (OR = 2.8 and 1.9, resp., P < 0.01). Also, in both age groups, current and former smokers had higher levels of tooth loss than nonsmokers (P < 0.001 and P < 0.05, resp.). In addition, tooth loss was positively related to metabolic abnormality for age group >35 years (adjusted OR = 1.29, P < 0.01). Conclusions. Tooth loss is highly prevalent in Iranian adult population. Community programs promoting oral health for prevention of tooth loss should be considered taking into account its major determinants including lower educational level, male gender, smoking, and metabolic abnormality. PMID:24228259

Keshteli, A. H.; Feizi, Awat; Savabi, Omid; Adibi, Peyman

2013-01-01

246

Microgrooved silicone subcutaneous implants in guinea pigs.  

PubMed

Cell-substratum interactions are of fundamental importance for the reaction of body tissues to surgically implanted foreign materials. In our study we investigated the influence of 2 microm wide microgrooves, with various depths (0.5-6 microm), on capsule formation around subcutaneous silicone implants, in an animal experiment. Silicone sheets with microtexture were glued around silicone tubes. These implants were placed subcutaneously in eight guinea pigs for 10 weeks. The implanted tubes were removed including all surrounding tissues, and processed for light microscopy and subsequent histomorphometrical evaluation. All removed implants were surrounded by a thin fibrous capsule, and it was observed that this capsule was separated from the implants by a thin, single layer of mono- and multinucleated phagocytotic cells. In histomorphometry no significant differences were seen in relation to the reaction towards the various textures. We conclude that microtextures do not have an effect on the morphological characteristics of capsule formation around silicone implants in soft tissue. PMID:10701463

Walboomers, X F; Jansen, J A

2000-03-01

247

An overview of zirconia dental implants: basic properties and clinical application of three cases.  

PubMed

Due to the possible aesthetic problems of titanium implants, the developments in ceramic implant materials are increasing. Natural tooth colored ceramic implants may be an alternative to overcome aesthetic problems. The purpose of this article is to give information about the basic properties of dental zirconia implants and present 3 cases treated with two-piece zirconia implants. Two-piece zirconia dental implants, 4.0 mm diameter and 11.5 mm in length, were inserted into maxillary incisor region. They were left for 6 months to osseointegrate. Panoramic and periapical radiographs were obtained and examined for bone-implant osseointegration. During the follow-up period the patients were satisfied with their prosthesis and no complication was observed. PMID:25106014

Banko?lu Güngör, Merve; Ayd?n, Cemal; Y?lmaz, Handan; Gül, Esma Ba?ak

2014-08-01

248

Comparison of a Slanted-Tooth See-Through Labyrinth Seal to a Straight-Tooth See-Through Labyrinth Seal for Rotordynamic Coefficients and Leakage  

E-print Network

This research compares the leakage and rotordynamic characteristics of a slanted-tooth labyrinth seal to a conventional straight-tooth labyrinth. Detailed results comparing the rotordynamic coefficients and leakage parameters of a slanted-tooth see...

Mehta, Naitik

2012-07-16

249

Tooth configuration for an earth boring bit  

SciTech Connect

A polycrystalline diamond cutting element in a earth boring bit is affixed to the bit face by an improved tooth. The tooth includes a prepad extending from the face of the mining bit contiguous to and substantially congruous with that portion of a polycrystalline diamond element also extending from the bit face. A trailing support is provided behind the polycrystalline diamond element and is similarly contiguous and substantially congruous therewith so that a generally singular geometrically shaped body is formed by the prepad, the polycrystalline diamond element and the trailing support. The prepad and trailing support are integrally formed from the matrix material of the rotary bit and are generally arcuate about a radius centered on the bit face. The polycrystalline diamond element is thus securely retained on the bit face while exposing a maximum extent of the polycrystalline diamond element sandwiched between the prepad and trailing support.

Grappendorf, R. H.; Brown, J. L.

1985-02-19

250

Verification of the mechanostat theory in mandible remodeling after tooth extraction: animal study and numerical modeling.  

PubMed

Bone tissue is capable of remodeling in response to environmental and physiological conditions. Mechanical loading is thought to be one of the most important environmental factors, affecting bone status. Mechanostat theory, which classifies bone behavior on the basis of the mechanical strain, has been vastly applied in cases of long bones. The present study surveyed the applicability of mechanostat theory in interpretation and anticipation of structural changes of the mandible due to tooth extraction, through experimental measurements and numerical modeling. The mandibular left first molar tooth of a 2-year-old male mongrel dog was extracted. Computed tomography (CT) images of the mandible were taken before, immediately after, and 1 year after extraction. Finite element models were constructed from the CT images and analyzed to evaluate the von Mises strain distribution within the mandible, specifically near the extraction site. Marked resorption around the extraction site and significant height reductions in the buccal and lingual ridges around the socket were observed one year after tooth removal. The deep socket made by extraction was filled and replaced by a smooth surface through bone remodeling in response to masticatory loading. Resultant strain analyses revealed a noticeable decline in strain level around the socket after tooth extraction, which activated bone remodeling according to mechanostat theory. At 1-year post-extraction, the strain magnitudes had increased significantly to near pre-extraction values. Alterations in the strain magnitudes along the mesio-distal axis were quantified for each stage and compared with the Mechanostat predefined regions. The FE results were surveyed in combination with the ridge height reductions, along the mesio-distal direction. Strain contours of the post-extraction stages were compatible with predictions by mechanostat theory. These findings validate the ability of mechanostat theory to describe mandible remodeling and predict post-extraction structural changes that occur near the extraction site. These results could be applied in dental treatment planning and implant design. PMID:23523125

Mahnama, Ali; Tafazzoli-Shadpour, Mohammad; Geramipanah, Farideh; Mehdi Dehghan, Mohammad

2013-04-01

251

Regulation of CCN2 gene expression and possible roles in developing tooth germs.  

PubMed

CCN proteins are extracellular and cell-associated molecules involved in several developmental processes, but their expression patterns and regulation in tooth development remain unclear. Here we first determined the expression patterns of CCN genes in mouse tooth germs. We found that at early stages CCN2 was detected in dental lamina, dental mesenchyme, and primary enamel knot, while other CCN family members were expressed broadly. By the bell stage, all members were expressed in differentiating odontoblasts and ameloblasts, but CCN1 and CCN2 transcripts were conspicuous in differentiating osteoblasts in dental follicle. Next, we asked what signalling molecules regulate CCN2 expression and what roles CCN2 may have. We found that upon surgical removal of dental epithelium CCN2 was not longer expressed in dental mesenchyme in cultured bud stage germs. Implantation of beads pre-coated with BMPs and FGFs onto E12-13 mandibular explants induced CCN2 expression in dental mesenchyme. There was a dose-dependent effect of BMP-4 on CCN2 induction; a concentration of 100 ng/?l was able to induce strong CCN2 expression while a minimum concentration of 25 ng/?l was needed to elicit appreciable expression. Importantly, Noggin treatment inhibited endogenous and BMP-induced CCN2 expression, verifying that CCN2 expression in developing tooth germs requires BMP signalling. Lastly, we found that rCCN2 stimulated proliferation in dental mesenchyme in a dose-dependent manner. Together, the data indicate that expression of CCN genes is spatio-temporally regulated in developing tooth germs. CCN2 expression appears to depend on epithelial and mesenchymal-derived signalling factors, and CCN2 can elicit strong proliferation in dental mesenchyme. PMID:24112732

Kanyama, Manabu; Shimo, Tsuyoshi; Sugito, Hiroki; Nagayama, Motohiko; Kuboki, Takuo; Pacifici, Maurizio; Koyama, Eiki

2013-11-01

252

Stem cells and tooth tissue engineering  

Microsoft Academic Search

The notion that teeth contain stem cells is based on the well-known repairing ability of dentin after injury. Dental stem\\u000a cells have been isolated according to their anatomical locations, colony-forming ability, expression of stem cell markers,\\u000a and regeneration of pulp\\/dentin structures in vivo. These dental-derived stem cells are currently under increasing investigation\\u000a as sources for tooth regeneration and repair. Further

Amanda H.-H. Yen; Paul T. Sharpe

2008-01-01

253

Magnesium in tooth enamel and synthetic apatites  

Microsoft Academic Search

Summary  The literature on how Mg is present in tooth enamel and on the incorporation of Mg in synthetic apatites is reviewed. Then\\u000a a theoretical consideration is given on the basis of ionic radii about the incorporation of Mg in F-, Cl- and OH-apatite.\\u000a Finally, the results are given of experiments on the incorporation of Mg in fluor, chlor, hydroxy, and

R. A. Terpstra; F. C. M. Driessens

1986-01-01

254

Update on Charcot-Marie-Tooth Disease  

Microsoft Academic Search

Charcot-Marie-Tooth disease (CMT) disease encompasses a genetically heterogeneous group of inherited neuropathies, also known\\u000a as hereditary motor and sensory neuropathies. CMT results from mutations in more than 40 genes expressed in Schwann cells\\u000a and neurons causing overlapping phenotypes. The classic CMT phenotype reflects length-dependent axonal degeneration characterized\\u000a by distal sensory loss and weakness, deep tendon reflex abnormalities, and skeletal deformities.

Ágnes Patzkó; Michael E. Shy

2011-01-01

255

Iron implantation in ?-Al2O3  

Microsoft Academic Search

Single crystal and ceramic ?-Al2O3 samples were implanted with 57Fe ions at different fluences, and different charge states of Fe were determined. The hyperfine interaction data showed that implanted ions are in Fe0, Fe2+, and Fe3+ states depending on the fluence. It is shown that after the annealing of the implanted sample in a 2.5CO 1CO2 atmosphere Fe spinel forms.

I. De´zsi; Cs. Fetzer

2008-01-01

256

[Dental implantations of ceramics-coated metals].  

PubMed

Recent studies and personal experience of the Authors in the field of dental implants have encountered the same fundamental problem which arises with orthopedic prosthesis procedures. The basic problem is that of adhesion between the bone tissue and the metal implant. Chrome-cobalt alloy, Tantalum and Titanium are the metals of most recent use. The Authors therefore proceeded to investigate the behaviour of alveolar bone tissue in the proximity of artificial teeth made of alloy (platinum-gold) covered with ceramic, as used in prosthetic dentistry. The experiment was carried out in a dog and a man. In the dog, two of its mandibular teeth were substituted with the same ceramic-gold implants: the first, a replica of natural tooth, was placed in the socket and held in place by metal splint and mandibular circumferential wirings. The other implant, without a replicated crown, was left free, within the alveolus, without contacting the near or opposing teeth. A solid smooth surfaced alumina device, shaped like a small cylinder, was implanted in the upper femoral epiphysis of the same animal. PMID:1105133

Cini, L; Gasparini, F; Michieli, S; Pizzoferrato, A; Sandrolini-Cortesi, S

1975-01-01

257

Influence of Abutment Design on Clinical Status of Peri-Implant Tissues  

Microsoft Academic Search

Objective: To compare the clinical soft tissue responses around implant tooth-supported 3-unit bridges using tapered abutments with those using butt-joint abutments. Methods: In a split-mouth design study, 8 mm Ankylos (Dentsply Friadent, Germany) implants were placed in the second mandibular molar region of 8 adult Macaca fascicularis monkeys about I month after extraction of all mandibular molars. After 3 months

T. B. Taiyeb-Ali; C. G. Toh; C. H. Siar; D. Seiz; S. T. Ong

2009-01-01

258

Simulated Single Tooth Bending of High Temperature Alloys  

NASA Technical Reports Server (NTRS)

Future unmanned space missions will require mechanisms to operate at extreme conditions in order to be successful. In some of these mechanisms, very high gear reductions will be needed to permit very small motors to drive other components at low rotational speed with high output torque. Therefore gearing components are required that can meet the mission requirements. In mechanisms such as this, bending fatigue strength capacity of the gears is very important. The bending fatigue capacity of a high temperature, nickel-based alloy, typically used for turbine disks in gas turbine engines and two tool steel materials with high vanadium content, were compared to that of a typical aerospace alloy-AISI 9310. Test specimens were fabricated by electro-discharge machining without post machining processing. Tests were run at 24 and at 490 C. As test temperature increased from 24 to 490 C the bending fatigue strength was reduced by a factor of five.

Handschuh, Robert, F.; Burke, Christopher

2012-01-01

259

Biomechanics of incisor retraction with mini-implant anchorage.  

PubMed

Mini-implants have been successfully incorporated into orthodontic practice all over the world. One of the most popular applications of mini-implant anchorage is to facilitate retraction of the anterior teeth. This article reviews the mechanics involved in anterior tooth retraction with mini-implant supported anchorage. An attempt has been made to synthesize information available in the literature and present it in a manner that is easily understandable from a clinical perspective. We discuss the fundamental differences mini-implant based incisor retraction has when compared to conventional techniques, mechanical factors affecting this process and provide a step-by-step analysis of incisor retraction. In addition, various models of space closure are discussed that have evolved through careful evaluation of in vitro and in vivo experiments. PMID:25138361

Upadhyay, Madhur; Yadav, Sumit; Nanda, Ravindra

2014-09-01

260

Implant Chips  

NSDL National Science Digital Library

A group of eight people, including all members of one Florida family, had an implant chip, roughly the size of a grain of rice, injected under their skin on Friday, May 10. Manufactured by Applied Digital Solutions (ADS), the chips store a special identification number that enables the retrieval of personal and medical information. In the event of a medical emergency, a special handheld scanner activates the dormant digital implant, which provides identification data with which medical personnel can query ADS's database, the location of the patient's medical records. Alzheimer's patients seem to be the most promising market for this technology, even though other people, like the Florida family, hope to benefit from it as well. Another product that ADS offers is called Digital Angel, a wearable global positioning system (GPS) device that, among other things, can track in real time the wearer's physical movements. In the future, ADS is planning to release a product that will utilize both of these technologies: an implanted GPS-enabled chip. Unlike VeriChip, though, the GPS-enabled implant would require Food and Drug Administration (FDA) approval, meaning the US market won't see its introduction until after FDA testing. Many organizations, ranging from privacy advocates to religious groups, have already denounced VeriChip and its eventually successors, associated them with "Big Brother" and the biblical "Mark of the Beast."To read about the eight people that received their implants, look at the first and second sites, articles from the Los Angeles Times and Miami Herald respectively. For a non-US perspective, view the news story posted by the British Broadcasting Company (BBC). The fourth site, an extensive analysis of the subject from ABC News, should give readers a broader understanding of implanted chips and their potential uses. Two sites from ADS are next -- VeriChip's product pages and the press release that details a FDA's decision regarding VeriChip in April, 2002. Finally, the last two sites give more information on Digital Angel and a sample of GPS technology already in use.

Schroeder, Ted.

2002-01-01

261

Local Synthesis and Tooth Contact Analysis of Face-Milled, Uniform Tooth Height Spiral Bevel Gears  

NASA Technical Reports Server (NTRS)

Face-milled spiral bevel gears with uniform tooth height are considered. An approach is proposed for the design of low-noise and localized bearing contact of such gears. The approach is based on the mismatch of contacting surfaces and permits two types of bearing contact either directed longitudinally or across the surface to be obtained. Conditions to avoid undercutting were determined. A Tooth Contact Analysis (TCA) was developed. This analysis was used to determine the influence of misalignment on meshing and contact of the spiral bevel gears. A numerical example that illustrates the theory developed is provided.

Litvin, F. L.; Wang, A. G.

1996-01-01

262

Tooth form design supporting system in module design  

NASA Astrophysics Data System (ADS)

A lot of time was spent in designing the tooth form because there was no Computer Aided Design (CAD) system suitable for designing the tooth form of gears. A CAD system to support the tooth form design to promote efficiency of the tooth form design of gears for a wristwatch was developed. This system can perform calculation of torque transmission factor of gears, automatic drawing of tooth form drawing, and engagement simulation, and by utilizing this system the tooth form can be designed in less than one fourth of the time required by the conventional method. The characteristics of the system used to calculate the torque transmission factor of a pair of gears are summarized and the displayed results are shown.

Nagasawa, Junji; Namiki, Ryou; Tanaka, Souichi; Aoyama, Shigeru

263

Contraceptive Implants  

Microsoft Academic Search

Subdermal contraceptive implants offer women long-acting, controlled release of progestins. Over the past 20 years, they have\\u000a been approved in more than 60 countries and used by more than 11 million women worldwide. Their high efficacy along with ease\\u000a of use make them a good contraceptive option for women who require progestin-only methods because they should not use estrogen,\\u000a teens

Philip D. Darney

264

Effective sealing of a disk cavity using a double-toothed rim seal  

Microsoft Academic Search

The sealing characteristics of an advanced air-cooled turbo-expander disk cavity are examined employing laser sheet flow visualization and static pressure measurements. Tests are conducted on a simplified half-scale model of an actual low pressure turbo-expander first-stage disk cavity. The superior performance of the seal studied is confirmed by comparison with a single-toothed rim seal and a simple axial rim seal.

S. H. Bhavnani; V. I. Khilnani; L.-C. Tsai; J. M. Khodadadi; J. S. Goodling; J. Waggott

1992-01-01

265

Effective sealing of a disk cavity using a double-toothed rim seal  

NASA Astrophysics Data System (ADS)

The sealing characteristics of an advanced air-cooled turbo-expander disk cavity are examined employing laser sheet flow visualization and static pressure measurements. Tests are conducted on a simplified half-scale model of an actual low pressure turbo-expander first-stage disk cavity. The superior performance of the seal studied is confirmed by comparison with a single-toothed rim seal and a simple axial rim seal.

Bhavnani, S. H.; Khilnani, V. I.; Tsai, L.-C.; Khodadadi, J. M.; Goodling, J. S.; Waggott, J.

1992-06-01

266

[Large dentigerous cyst caused by retained tooth 25].  

PubMed

Follicular cysts are benign, non-inflammatory odontogenic cysts, usually painless and discovered during routine radiographic examination. The article describes a case of a large follicular cyst with retained tooth 25. Pantomographic x ray showed the presence of a large follicular cyst located on the side of the impacted 25 tooth. The cyst has been enucleated and the tooth extracted surgically with subsequent closure of oro-antral communication. After 3 months orthodontic treatment was initiated. PMID:25182400

Janas, Anna; Stelmach, Rafa?; Osica, Piotr

2014-01-01

267

Neurovascular disturbances after implant surgery.  

PubMed

With a steadily increasing impact of oral implant placement in daily practice, the number of reported surgical complications has also been growing. Recent studies reveal significant variation in the occurrence and morphology of neurovascular canal structures in the jaw bone. All those structures contain a neurovascular bundle, the diameter of which may be large enough to cause clinically significant damage. Therefore, it has become obvious that presurgical radiographic planning of jaw-bone surgery should pay attention to the neurovascular structures and their likely variations, in addition to examining many other factors, such as jaw-bone morphology and volume, bone trabecular structure and the absence of bone or tooth pathology. A critical review is accomplished to explore the potential risks for neurovascular complications after implant placement, with evidence derived from histologic, anatomic, clinical and radiologic studies. In this respect, cross-sectional imaging can often be advocated, as it is obvious that the inherent three-dimensional nature of jaw-bone anatomy may clearly benefit from a detailed spatial image analysis. Although this could initially be realized by conventional computed tomography, in current practice, dentomaxillofacial cone beam computed tomography might be used, as it offers high-quality images at low radiation dose levels and costs. PMID:25123768

Jacobs, Reinhilde; Quirynen, Marc; Bornstein, Michael M

2014-10-01

268

Tooth positioners and their effects on treatment outcome.  

PubMed

Malocclusion can also be corrected by means of clear removable appliances called as "tooth positioners" or "aligners". A tooth positioner is used to control settling and to minimize or eliminate relapse of the teeth after an orthodontic treatment. In this article, a complete review of the objectives, course of treatment, fabrication, and the materials used for fabrication of tooth positioners along with their importance and disadvantages were discussed. Tooth positioners did improve the overall orthodontic treatment outcome as quantified by the ABO (American Board of orthodontics) objective scoring method. But once the initial occlusal contact was achieved, the vertical movement of teeth was found to be inhibited. PMID:24082720

Pravindevaprasad, A; Therese, Beena Agnes

2013-07-01

269

The role of the dental lamina in mammalian tooth replacement.  

PubMed

We have applied the ferret, Mustela putorius furo, as a model for tooth replacement. Ferret has a heterodont dentition, which includes all tooth families, and all antemolar teeth are replaced. Compared with mouse, the ferret therefore has a less derived mammalian dentition resembling that of humans. We have studied tooth replacement in serial histological sections in embryonic and young postnatal ferrets. Our observations indicate that the replacement teeth form from the dental lamina that is intimately connected to the lingual aspect of the deciduous tooth enamel organ. It grows as an offshoot from the enamel organ, elongates in cervical direction and later buds to give rise to the replacement tooth. The extent of the dental lamina growth, preceding replacement tooth budding, varied between different teeth. The dynamic gene expression patterns of Sostdc1, Shh and Axin2 brought new insight into the signal networks regulating the tooth replacement process. The distinct expression of Sostdc1 at the interface between the dental lamina and the deciduous tooth is the first indication of a specific tissue identity of the dental lamina. We suggest that the reactivation of a competent dental lamina is pivotal for the replacement tooth formation. PMID:19137538

Järvinen, Elina; Tummers, Mark; Thesleff, Irma

2009-06-15

270

‘Elephant’ graft to assist implant-retained nasal prosthesis  

Microsoft Academic Search

Large rhinectomy defects can be reconstructed with endosseous craniofacial implants and an alloplastic implant-retained prosthesis. The survival of the implants and prosthesis is aided by the placement of split skin grafts. A simple and effective technique is described to enable accurate placement of a split skin graft in a single piece, by shaping it ‘like an elephant’.

M. Ethunandan; I. P. Downie

2008-01-01

271

Effect of Multiple Adhesive Coating on Microshear Bond Strength to Primary Tooth Dentin  

PubMed Central

Objective: Multiple adhesive coating is a controversial topic, especially in primary dentition that should be clarified. We evaluated the effect of multiple consecutive adhesive resin coatings on the microshear bond strength (?SBS) of composite resin to primary tooth dentin utilizing a filled (Adper Single Bond Plus) and an unfilled (Adper Single Bond) adhesive resin. Materials and Methods: Thirty extracted primary canines were randomly allocated into two groups based on the adhesive used. Dentin occlusal surfaces were exposed and further polished on 400, 600 and 800-grit silicon-carbide paper. The surfaces were divided into two halves in the labial-lingual orientation. After etching, the adhesives were used either in double coats, or four coats on the halves of the same tooth followed by air evaporation for each layer and finally light curing. Cylinders of composite were bonded to the dentin surfaces. After 24 h shear bond testing was evaluated by Bisco tensile tester. ANOVA, Student t test and paired t test were used for statistical analysis. Results: The mean (standard deviation) for double coats or four coats in single bond were 31.99 (2.94) and 30.25 (2.69), while they were 29.18 (3.35) and 31.26 (2.07) in single bond plus, respectively. No significant differences were found between the double coated specimens and those receiving four coatings with both adhesives (p>0.05). Micro SBS values of Single Bond double coated specimens were significantly higher than Single Bond Plus (p=0.02). In four-coated specimens, there were no significant differences between Single Bond and Single Bond Plus (p=0.26). Conclusion: Applying four coats of adhesive did not improve the ?SBS to primary tooth dentin. PMID:23724217

Malekafzali, Beheshteh; Ghasemi, Amir; Torabzadeh, Hassan; Hamedani, Reza; Tadayon, Nekoo

2013-01-01

272

Gene Expression Profiling during Murine Tooth Development  

PubMed Central

The aim of this study was to describe the expression of genes, including ameloblastin (Ambn), amelogenin X chromosome (Amelx), and enamelin (Enam) during early (pre-secretory) tooth development. The expression of these genes has predominantly been studied at post-secretory stages. Deoxyoligonucleotide microarrays were used to study gene expression during development of the murine first molar tooth germ at 24?h intervals, starting at the 11th embryonic day (E11.5), and up to the 7th day after birth (P7). The profile search function of Spotfire software was used to select genes with similar expression profile as the enamel genes (Ambn, Amelx, and Enam). Microarray results where validated using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR), and translated proteins identified by Western-blotting. In situ localization of the Ambn, Amelx, and Enam mRNAs were monitored from E12.5 to E17.5 using deoxyoligonucleotide probes. Bioinformatics analysis was used to associate biological functions with differentially expressed (DE; p???0.05) genes. Microarray results showed a total of 4362 genes including Ambn, Amelx, and Enam to be significant DE throughout the time-course. The expression of the three enamel genes was low at pre-natal stages (E11.5–P0) increasing after birth (P1–P7). Profile search lead to isolation of 87 genes with significantly similar expression to the three enamel proteins. These mRNAs were expressed in dental epithelium and epithelium derived cells. Although expression of Ambn, Amelx, and Enam were lower during early tooth development compared to secretory stages enamel proteins were detectable by Western-blotting. Bioinformatic analysis associated the 87 genes with multiple biological functions. Around 35 genes were associated with 15 transcription factors. PMID:22866057

Landin, Maria A. dos Santos Silva; Shabestari, Maziar; Babaie, Eshrat; Reseland, Janne E.; Osmundsen, Harald

2012-01-01

273

Canine tooth in hand - A rare entity  

PubMed Central

The hand plays an important role in day to day activities and is more prone for accidental injuries. Injuries to the hand are frequently associated with foreign body penetration. Many a times the foreign body is not detected at the initial visit and can later present with other complications. We present a case of canine tooth presenting as a retained foreign body in the hand following a dog bite. The article stresses the importance of looking for foreign bodies in penetrating hand injuries, even in wounds that seem to be minor in nature.

Ranganatha, B.T.; Pawan Kumar, K.M.

2014-01-01

274

Measurement of Gear Tooth Dynamic Friction  

NASA Technical Reports Server (NTRS)

Measurements of dynamic friction forces at the gear tooth contact were undertaken using strain gages at the root fillets of two successive teeth. Results are presented from two gear sets over a range of speeds and loads. The results demonstrate that the friction coefficient does not appear to be significantly influenced by the sliding reversal at the pitch point, and that the friction coefficient values found are in accord with those in general use. The friction coefficient was found to increase at low sliding speeds. This agrees with the results of disc machine testing.

Rebbechi, Brian; Oswald, Fred B.; Townsend, Dennis P.

1996-01-01

275

Critical buccal bone dimensions along implants.  

PubMed

The buccal bone plate is a component of the alveolar process tightly related to the tooth it supports. A plethora of physiological and pathological events can induce its remodeling. Understanding this remodeling process and its extent is of major importance for the practitioner as it can affect the functional and esthetic outcome of implant surgery at the involved sites. Bone remodeling and resorption of the buccal bone plate are inevitable after tooth loss or extraction. To limit resorption, several ridge-preservation techniques of varying efficacy have been described. Bone resorption is equally found to occur upon implant placement and is thought to be a result of the surgical trauma inflicted as well as an adaptation process of the tissues to the new foreign body. Because of the implications of bone resorption on the soft-tissue levels and the general esthetic outcome, it is of primary importance for the practitioner to be able to evaluate the hard tissues and the inherent resorption risks in an effort to optimize the treatment strategies. Based on limited short-term data, the present general opinion advises the need for a 2-mm-thick buccal bone plate in order to avoid vertical bone resorption. PMID:25123763

Merheb, Joe; Quirynen, Marc; Teughels, Wim

2014-10-01

276

The study of damage produced by H-ion and He-ion implantation in Lithium tantalate crystal  

NASA Astrophysics Data System (ADS)

LiTaO3 single crystals were implanted by 100keV H-ion or He-ion. The results indicate that H-ion implantation creates a lower damage level than the He-ion implantation does, but the yield of oxygen vacancy produced by H-ion implantation is far higher than by He-ion implantation.

Pang, L. L.; Wang, Z. G.; Yao, C. F.; Sun, J. R.; Cui, M. H.; Wei, K. F.; Shen, T. L.; Sheng, Y. B.; Zhu, Y. B.; Li, Y. F.; Chang, H. L.; Wang, J.; Zhu, H. P.

2014-04-01

277

Auditory Midbrain Implant: A Review  

PubMed Central

The auditory midbrain implant (AMI) is a new hearing prosthesis designed for stimulation of the inferior colliculus in deaf patients who cannot sufficiently benefit from cochlear implants. The authors have begun clinical trials in which five patients have been implanted with a single shank AMI array (20 electrodes). The goal of this review is to summarize the development and research that has led to the translation of the AMI from a concept into the first patients. This study presents the rationale and design concept for the AMI as well a summary of the animal safety and feasibility studies that were required for clinical approval. The authors also present the initial surgical, psychophysical, and speech results from the first three implanted patients. Overall, the results have been encouraging in terms of the safety and functionality of the implant. All patients obtain improvements in hearing capabilities on a daily basis. However, performance varies dramatically across patients depending on the implant location within the midbrain with the best performer still not able to achieve open set speech perception without lip-reading cues. Stimulation of the auditory midbrain provides a wide range of level, spectral, and temporal cues, all of which are important for speech understanding, but they do not appear to sufficiently fuse together to enable open set speech perception with the currently used stimulation strategies. Finally, several issues and hypotheses for why current patients obtain limited speech perception along with several feasible solutions for improving AMI implementation are presented. PMID:19762428

Lim, Hubert H.; Lenarz, Minoo; Lenarz, Thomas

2009-01-01

278

Common developmental pathways link tooth shape to regeneration  

PubMed Central

In many non-mammalian vertebrates, adult dentitions result from cyclical rounds of tooth regeneration wherein simple unicuspid teeth are replaced by more complex forms. Therefore and by contrast to mammalian models, the numerical majority of vertebrate teeth develop shape during the process of replacement. Here, we exploit the dental diversity of Lake Malawi cichlid fishes to ask how vertebrates generally replace their dentition and in turn how this process acts to influence resulting tooth morphologies. First, we used immunohistochemistry to chart organogenesis of continually replacing cichlid teeth and discovered an epithelial down-growth that initiates the replacement cycle via a labial proliferation bias. Next, we identified sets of co-expressed genes from common pathways active during de novo, lifelong tooth replacement and tooth morphogenesis. Of note, we found two distinct epithelial cell populations, expressing markers of dental competence and cell potency, which may be responsible for tooth regeneration. Related gene sets were simultaneously active in putative signaling centers associated with the differentiation of replacement teeth with complex shapes. Finally, we manipulated targeted pathways (BMP, FGF, Hh, Notch, Wnt/?-catenin) in vivo with small molecules and demonstrated dose-dependent effects on both tooth replacement and tooth shape. Our data suggest that the processes of tooth regeneration and tooth shape morphogenesis are integrated via a common set of molecular signals. This linkage has subsequently been lost or decoupled in mammalian dentitions where complex tooth shapes develop in first generation dentitions that lack the capacity for lifelong replacement. Our dissection of the molecular mechanics of vertebrate tooth replacement coupled to complex shape pinpoints aspects of odontogenesis that might be re-evolved in the lab to solve problems in regenerative dentistry. PMID:23422830

Fraser, Gareth J.; Bloomquist, Ryan F.; Streelman, J. Todd

2013-01-01

279

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

2011-04-01

280

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

2010-04-01

281

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

... 2014-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

2014-04-01

282

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

2012-04-01

283

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

2013-04-01

284

Hierarchical structure and biomineralization in cricket tooth  

E-print Network

Cricket is a truculent insect with stiff and sharp teeth as a fighting weapon. The structure and possible biomineralization of the cricket teeth are always interested. Synchrotron radiation X-ray fluorescence, X-ray diffraction and small angle X-ray scattering techniques were used to probe the element distribution, possible crystalline structures and size distribution of scatterers in cricket teeth. Scanning electron microscope was used to observe the nanoscaled structure. The results demonstrate that Zn is the main heavy element in cricket teeth. The surface of the cricket teeth has a crystalline compound like ZnFe2(AsO4)2(OH)2(H2O)4. While, the interior of the teeth has a crystalline compound like ZnCl2, which is from the biomineralization. The ZnCl2-like biomineral forms nanoscaled microfibrils and their axial direction points at the top of tooth cusp. The microfibrils aggregate random into intermediate filaments, forming a hierarchical structure. A sketch map of the cricket tooth cusp was proposed and a d...

Xing, Xueqing; Cai, Quan; Mo, Guang; Du, Rong; Chen, Zhongjun; Wu, Zhonghua

2012-01-01

285

Hierarchical structure and biomineralization in cricket tooth  

E-print Network

Cricket is a truculent insect with stiff and sharp teeth as a fighting weapon. The structure and possible biomineralization of the cricket teeth are always interested. Synchrotron radiation X-ray fluorescence, X-ray diffraction and small angle X-ray scattering techniques were used to probe the element distribution, possible crystalline structures and size distribution of scatterers in cricket teeth. Scanning electron microscope was used to observe the nanoscaled structure. The results demonstrate that Zn is the main heavy element in cricket teeth. The surface of the cricket teeth has a crystalline compound like ZnFe2(AsO4)2(OH)2(H2O)4. While, the interior of the teeth has a crystalline compound like ZnCl2, which is from the biomineralization. The ZnCl2-like biomineral forms nanoscaled microfibrils and their axial direction points at the top of tooth cusp. The microfibrils aggregate random into intermediate filaments, forming a hierarchical structure. A sketch map of the cricket tooth cusp was proposed and a detailed discussion was given in this paper.

Xueqing Xing; Yu Gong; Quan Cai; Guang Mo; Rong Du; Zhongjun Chen; Zhonghua Wu

2012-03-20

286

On the Gap-Tooth direct simulation Monte Carlo method  

E-print Network

This thesis develops and evaluates Gap-tooth DSMC (GT-DSMC), a direct Monte Carlo simulation procedure for dilute gases combined with the Gap-tooth method of Gear, Li, and Kevrekidis. The latter was proposed as a means of ...

Armour, Jessica D

2012-01-01

287

[Tooth decay and its complication prognosis in smokers].  

PubMed

The study focuses on complicated and non-complicated tooth decay course and prognosis in smokers. Oral status, prevention and treatment effectiveness was assessed in 330 non-smokers and 345 smoking patients. The results allowed concluding with guidelines for tooth decay prevention and treatment in smokers. PMID:24576962

Orekhova, L Iu; Osipova, M V

2014-01-01

288

Nonplanar trapezoidal tooth log-periodic antennas: Design and electromagnetic  

E-print Network

Nonplanar trapezoidal tooth log-periodic antennas: Design and electromagnetic modeling O¨ zgu 2005. [1] Nonplanar trapezoidal tooth log-periodic (LP) antennas are investigated by combining log-periodic antennas: Design and electromagnetic modeling, Radio Sci., 40, RS5010, doi:10.1029/2004RS

Gürel, Levent

289

Optimization of Rotor Tooth Shape of Aerospace Homopolar Alternators  

Microsoft Academic Search

In the first part of the optimization process, the width and depth of the rotor tooth are incrementally varied for two airgap radial lengths and two field excitations. In the second part the tooth shape that would yield a sinusoidal voltage is investigated. The numerical results are represented by curves for the no-load radial flux density in a 95 KVA,

R. E. Hopkins; E. A Erdelyi

1965-01-01

290

Dietary plasticity in ungulates: Insight from tooth microwear analysis  

Microsoft Academic Search

In recent years, tooth microwear has been used as a powerful tool for investigating mammalian diets in paleontological or archaeological contexts. Tooth microwear techniques were applied to a number of late Pleistocene assemblages of bison (Bison antiquus) from North America to analyze bison dietary traits, but more particularly, to test for dietary plasticity of the fossil species compared to their modern

Florent Rivals; Gina M. Semprebon

2011-01-01

291

3D Statistical Models for Tooth Surface Reconstruction  

E-print Network

, they only provide information about the crowns of the teeth but none of the roots, which are hidden of a tooth given partial information about its shape. A statistical model comprising a mean shape to the deformation modes. The method is shown to be efficient for the recovery of tooth shape given crown information

Boyer, Edmond

292

Bone physiology of tooth movement, ankylosis, and osseointegration  

Microsoft Academic Search

Tooth movement is a highly conserved physiologic mechanism for continuous adaptation of the dentition. Physiologic drift of teeth is essential for maintaining appropriate stomatognathic function over a lifetime. Orthodontics is a therapeutic exploitation of this physiologic mechanism. The relative position of a tooth is dictated by the equilibrium of forces acting on it. The periodontium is an “organ” of functionally

W. Eugene Roberts

2000-01-01

293

Laser application in tooth bleaching: an update review.  

PubMed

Since the development of laser, a variety of potential applications for lasers in endodontics such as pulp diagnosis, disinfection of the root canal system, canal shaping, obturation of the root canal, apicoectomy, treatment of dentin hypersensitivity, and tooth bleaching have been proposed. The aim of this paper was to review the benefits and drawbacks of laser tooth bleaching. PMID:21471940

Mohammadi, Z; Palazzi, F; Giardino, L

2011-04-01

294

Functional fixation of autotransplanted tooth germs by using bioresorbable membranes  

Microsoft Academic Search

Objective. The purpose of this study was to evaluate the contribution of a bioresorbable membrane placement to the healing of immature teeth after autotransplantation of tooth buds. Study Design. Six cases were selected: 2 transplantations of wisdom teeth, 2 for premolar agenesis, 1 for ectopia, and 1 premolar in an incisor position. The crown of each tooth germ and the

Eric Gérard; Hervé Membre; Jean-François Gaudy; Patrick Mahler; Pierre Bravetti

2002-01-01

295

[Comperative study of implant surface characteristics].  

PubMed

The osseointegration between the implant and its' bone environment is very important. The implants shall meet the following requirements: biocompatibility, rigidity, resistance against corrosion and technical producibility. In our present study surface morphology and material characteristics of different implants (Denti Bone Level, Denti Zirconium C, Bionika CorticaL, Straumann SLA, Straumann SLA Active, Dentsply Ankylos and Biotech Kontact implant) were investigated with scanning electron microscopy and energy-dispersive X-ray spectroscopy. The possible surface alterations caused by the manufacturing technology were also investigated. During grit-blasting the implants' surface is blasted with hard ceramic particles (titanium oxide, alumina, calcium phosphate). Properties of blasting material are critical because the osseointegration of dental implants should not be hampered. The physical and chemical features of blasting particles could importantly affect the produced surfaces of implants. Titanium surfaces with micro pits are created after immersion in mixtures of strong acids. On surfaces after dual acid-etching procedures the crosslinking between fibrin and osteogenetic cells could be enhanced therefore bone formation could be directly facilitated on the surface of the implant. Nowadays there are a number of surface modification techniques available. These can be used as a single method or in combination with each other. The effect of the two most commonly used surface modifications (acid-etching and grit-blasting) on different implants are demonstrated in our investigation. PMID:24551957

Katona, Bernadett; Daróczi, Lajos; Jenei, Attila; Bakó, József; Hegedus, Csaba

2013-12-01

296

Short implant in limited bone volume.  

PubMed

Rehabilitation of severely resorbed jaws with dental implants remains a surgical and prosthetic challenge for clinicians. The purpose of this review was to evaluate the available data on short-length implants and discuss their indications and limitations in daily clinical practice. A structured review of MEDLINE and a manual search were conducted. Thirty-two case series devoted to short-length implants, 14 reviews and 3 randomized controlled trials were identified. Of this group of papers, we can conclude that short-length implants can be successfully used to support single and multiple fixed reconstructions in posterior atrophied jaws, even in those with increased crown-to-implant ratios. The use of short-length implants allows treatment of patients who are unable to undergo complex surgical techniques for medical, anatomic or financial reasons. Moreover, the use of short-length implants in daily clinical practice reduces the need for complex surgeries, thus reducing morbidity, cost and treatment time. The use of short implants promotes the new concept of stress-minimizing surgery, allowing the surgeon to focus more on the correct three-dimensional positioning of the implant. PMID:25123762

Nisand, David; Renouard, Franck

2014-10-01

297

Patients' knowledge and awareness of dental implants in a Turkish subpopulation  

PubMed Central

PURPOSE The purpose of this study was to evaluate the patients' knowledge on dental implants in a Turkish subpopulation. MATERIALS AND METHODS Five hundred twenty seven Turkish adults referred to Yeditepe University Faculty of Dentistry, Istanbul, Turkey, were presented with a questionnaire including 20 questions regarding the level of information and awareness about the dental implants. The data were collected and statistical analyses were performed with Chi square test to compare the descriptive data. RESULTS Among 527 subjects, 54% were female and 46% were male with a mean age of 42.2 years. The rate of patients' implant awareness was 27.7%. When the patients were questioned about the treatment options for rehabilitation of tooth missing, 60.9% of patients were informed about fixed partial denture, followed by conventional complete denture (32.5%) and removable partial denture (24.9%). Six percent reported that they were very well informed about the dental implants whereas 48.2% were poorly informed. The information sources of the implants were from the dentist (44.5%), printed media (31.6%) and friends and acquaintances (17.3%), respectively. Sixteen percent of the population believed that their implants would last forever. CONCLUSION The dentists should give more detailed information to the patients about dental implants and tooth-supported fixed partial dentures in the future. PMID:24843399

Ozcak?r Tomruk, Ceyda; Sencift, Kemal

2014-01-01

298

MRI artefacts after Bonebridge implantation.  

PubMed

The new transcutaneous bone conduction implant (BCI) Bonebridge (BB, MED-EL) allows the skin to remain intact and therefore overcomes some issues related to percutaneous systems, such as skin reaction around the external screw and cosmetic complaints. According to manufacturer, BB is MRI conditional up to 1,5 Tesla (T). The artefact of the neurocranium after BB implantation is extensive as shown in the present report. This has to be taken into account when patients suffering conductive, mixed or single-sided hearing loss with candidacy for a BCI are counselled. In patients with comorbid intracranial tumour or other diseases of the brain that require imaging control scans with MRI percutaneous, BCI should be the implant of choice considering the very small artefact of the percutaneous screw in MRI. PMID:24639341

Steinmetz, C; Mader, I; Arndt, S; Aschendorff, A; Laszig, R; Hassepass, F

2014-07-01

299

Update on Charcot-Marie-Tooth Disease  

PubMed Central

Charcot-Marie-Tooth disease (CMT) disease encompasses a genetically heterogeneous group of inherited neuropathies, also known as hereditary motor and sensory neuropathies. CMT results from mutations in more than 40 genes expressed in Schwann cells and neurons causing overlapping phenotypes. The classic CMT phenotype reflects length-dependent axonal degeneration characterized by distal sensory loss and weakness, deep tendon reflex abnormalities, and skeletal deformities. Recent articles have provided insight into the molecular pathogenesis of CMT, which, for the first time, suggest potential therapeutic targets. Although there are currently no effective medications for CMT, multiple clinical trials are ongoing or being planned. This review will focus on the underlying pathomechanisms and diagnostic approaches of CMT and discuss the emerging therapeutic strategies. PMID:21080241

Patzko, Agnes; Shy, Michael E.

2011-01-01

300

Update on Charcot-Marie-Tooth disease.  

PubMed

Charcot-Marie-Tooth disease (CMT) disease encompasses a genetically heterogeneous group of inherited neuropathies, also known as hereditary motor and sensory neuropathies. CMT results from mutations in more than 40 genes expressed in Schwann cells and neurons causing overlapping phenotypes. The classic CMT phenotype reflects length-dependent axonal degeneration characterized by distal sensory loss and weakness, deep tendon reflex abnormalities, and skeletal deformities. Recent articles have provided insight into the molecular pathogenesis of CMT, which, for the first time, suggest potential therapeutic targets. Although there are currently no effective medications for CMT, multiple clinical trials are ongoing or being planned. This review will focus on the underlying pathomechanisms and diagnostic approaches of CMT and discuss the emerging therapeutic strategies. PMID:21080241

Patzkó, Agnes; Shy, Michael E

2011-02-01

301

Healing pattern of the mucous membrane after tooth extraction in the maxillary sinus  

PubMed Central

Purpose To investigate the healing pattern of the mucous membrane after tooth extraction necessitated by periodontal disease in the maxillary sinus. Methods One hundred and three patients with 119 maxillary sinuses were investigated. Before implant placement, cone-beam computed tomography (CT) scanning was performed. The causes of extraction, the time elapsed since extraction, smoking, periodontal disease in adjacent teeth, and gender were recorded. In addition, the thickness of the mucous membrane of the maxillary sinus and the height of residual alveolar bone at the extracted area were calculated from CT images. Results The thickness of the mucous membrane in the periodontal disease group (3.05±2.71 mm) was greater than that of the pulp disease group (1.92±1.78 mm) and the tooth fracture group (1.35±0.55 mm; P<0.05). The causes of extraction, the time elapsed since extraction, and gender had relationships with a thickening of the mucous membrane of the maxillary sinus (P<0.05). In contrast, the height of the residual alveolar bone at the extracted area, periodontal disease in adjacent teeth, and smoking did not show any relation to the thickening of the mucous membrane of the maxillary sinus. Conclusions The present study revealed distinct differences in healing patterns according to the causes of extraction in the maxillary sinus, especially periodontal disease, which resulted in more severe thickening of the mucous membrane. PMID:21394294

Yoo, Ji-Young; Pi, Sung-Hee; Kim, Yun-Sang; Jeong, Seong-Nyum

2011-01-01

302

Prevention of Streptococcus mutans infection of tooth surfaces by salivary antibody in Irus monkeys (Macaca fascicularis).  

PubMed Central

Four irus monkeys (Macaca fascicularis) were immunized with Streptococcus mutans 6715 killed cells and cell products by injection in the vicinity of the major salivary glands and by instillation into the parotid glands via the ducts. After immune group and a sham-immunized control group of monkeys were infected orally with viable strain 6715 organisms. Dental plaque samples were taken at intervals from the buccal and lingual grooves of the first permanent molars. These samples were evaluated for recovery of strain 6715 by cultural methods. In addition, individual samples were taken from 10 representative tooth surfaces and were evaluated by indirect immunofluorescent staining for strain 6715. Results showed that immune monkeys had fewer infected surfaces and fewer organisms on the infected surfaces than the control animals. These studies indicate that salivary antibody to cariogenic streptococci inhibits implantation of these organisms in dental plaque and may be protective against dental caries. PMID:1097337

Evans, R T; Emmings, F G; Genco, R J

1975-01-01

303

Investigating tooth loss and associated factors among older Taiwanese adults.  

PubMed

The aim of this study was to evaluate factors associated with tooth loss in older Taiwanese adults with different numbers of remaining teeth. This study evaluated oral health status and tooth loss among 2286 adults aged over 65. Subjects were classified according to number of teeth (Group 1 <20 teeth vs. Group 2 ?20 teeth). Tooth loss and oral health data were collected from the National Health Interview Survey (NHIS), compared between groups and analyzed by multivariate modeling. Group 1 subjects were older and had more partial dentures. Tooth loss was associated with self-limited food choices due to oral health status, and malnutrition. Tooth loss in Group 2 subjects was significantly associated with lower mental status. Tooth loss may predict cognitive status (odds ratio (OR) 1.30) and physical-disability (OR 1.79). Our results suggested that tooth loss was associated with age, more partial dentures, self-limited food choices, malnutrition, and lower mental and cognitive status and physical disability. PMID:24568967

Wang, Tze-Fang; Chen, Ying-Yu; Liou, Yiing-Mei; Chou, Chyuan

2014-01-01

304

Tooth-Binding Micelles for Dental Caries Prevention?  

PubMed Central

Maintenance of the effective local concentration of antimicrobials on the tooth surface is critical for the management of cariogenic bacteria in the oral cavity. We report on the design of a simple tooth-binding micellar drug delivery platform that would effectively bind to tooth surfaces. To achieve tooth-binding ability, the chain termini of biocompatible Pluronic copolymers were modified with a biomineral-binding moiety (i.e., alendronate). The micelles formulated with this polymer were shown to be able to swiftly (<1 min) bind to hydroxyapatite (HA; a model tooth surface) and gradually release the encapsulated model antimicrobial (farnesol). These tooth-binding micelles were negatively charged and had an average effective hydrodynamic diameter of less than 100 nm. In vitro biofilm inhibition studies demonstrated that the farnesol-containing tooth-binding micelles were able to provide significantly stronger inhibition of Streptococcus mutans UA159 biofilm formation on HA discs than the untreated blank control micelles (P < 0.0001). Upon further optimization, this delivery platform could provide an effective tool for caries prevention and treatment. PMID:19704121

Chen, Fu; Liu, Xin-Ming; Rice, Kelly C.; Li, Xue; Yu, Fang; Reinhardt, Richard A.; Bayles, Kenneth W.; Wang, Dong

2009-01-01

305

Endosseous dental implant vis-?-vis conservative management: Is it a dilemma?  

PubMed Central

To overview the current prospective of endosseous dental implant and conservative management. Although emphasis has been made in reinstating the oral functions, less consideration has been given to formulate the best treatment tactics in a particular situation. Properly restored, root canal treated natural teeth surrounded by healthy periodontium tissues yield a very high longevity, and periodontally compromised teeth that are treated and maintained regularly may have longer survival rate. Current trends in implantology have weakened the conservative paradigm, and practitioner's objectivity has been inclined more toward providing the tooth substitutes often flaunted as equal or even superior to conservation of natural tooth PMID:22442546

Chandra, Ramesh; Bains, Rhythm; Loomba, Kapil; Pal, U. S.; Ram, Hari; Bains, Vivek K.

2010-01-01

306

Odontogenic cell culture in PEGDA hydrogel scaffolds for use in tooth regeneration protocols.  

PubMed

In order to obtain a tooth-like structure, embryonic oral ectoderm cells (EOE) and bone marrow-derived stem cells (BMSC) were stratified within a synthetic hydrogel matrix (PEGDA) and implanted in the ileal mesentery of adult male Lewis rats. Whole-mount in situ hybridization was used to evaluate the expression of Pitx2, Shh and Wnt10a signals indicative of tooth initiation. In rats, expression of the three markers was present in the oral ectoderm starting at embryonic stage E12.5. which was therefore selected for cell harvesting. Embryos were obtained by controlled service of young female Lewis rats in which estrus was detected by impedance reading. At E12.5, pregnant rats were humanely euthanized and embryos were collected. The mandibular segment of the first branchial arch was dissected and the mesenchyme separated from the ectoderm by enzymatic digestion with pancreatin trypsin solution. BMSCs were collected by flushing the marrow of tibiae and femurs of adult Lewis rats with alpha-MEM and cultured in alpha-MEM in 25 cm2 flasks. Second passage BMSC's were recombined with competent oral ectoderm (E12.5-E13) stratifying them within a 3D PEGDA scaffold polymerized by exposure to UV (365 nm) inside a pyramidal polypropylene mold. Constructs were incubated from 24 to 48 hrs in alpha-MEM and then implanted for four to six weeks in the mesentery of adult male (3-6 month old) Lewis rats. 76 constructs were implanted (37 experimental, 27 negative controls and 12 positive controls). Upon maturation, constructs were harvested, fixed in buffered formalin, processed and stained with hematoxylin eosin (HE). Histological evaluation of the experimental and negative constructs showed that BMSCs underwent an apoptotic process due to lack of matrix interactions, known as anoikis, and were thus incapable of interacting with the competent ectoderm. In contrast, embryonic oral ectoderm was able to proliferate during the mesenteric implantation. In conclusion, PEGDA scaffolds are incompatible with BMSCs, therefore it is essential to continue the search for an ideal scaffold that allows proper tissue interactions. PMID:23798070

Jaramillo, Lorenza; Briceño, Ignacio; Durán, Camilo

2012-01-01

307

Tooth bleaching--a critical review of the biological aspects.  

PubMed

Present tooth-bleaching techniques are based upon hydrogen peroxide as the active agent. It is applied directly, or produced in a chemical reaction from sodium perborate or carbamide peroxide. More than 90% immediate success has been reported for intracoronal bleaching of non-vital teeth, and in the period of 1-8 years' observation time, from 10 to 40% of the initially successfully treated teeth needed re-treatment. Cervical root resorption is a possible consequence of internal bleaching and is more frequently observed in teeth treated with the thermo-catalytic procedure. When the external tooth-bleaching technique is used, the first subjective change in tooth color may be observed after 2-4 nights of tooth bleaching, and more than 90% satisfactory results have been reported. Tooth sensitivity is a common side-effect of external tooth bleaching observed in 15%-78% of the patients, but clinical studies addressing the risk of other adverse effects are lacking. Direct contact with hydrogen peroxide induced genotoxic effects in bacteria and cultured cells, whereas the effect was reduced or abolished in the presence of metabolizing enzymes. Several tumor-promoting studies, including the hamster cheek pouch model, indicated that hydrogen peroxide might act as a promoter. Multiple exposures of hydrogen peroxide have resulted in localized effects on the gastric mucosa, decreased food consumption, reduced weight gain, and blood chemistry changes in mice and rats. Our risk assessment revealed that a sufficient safety level was not reached in certain clinical situations of external tooth bleaching, such as bleaching one tooth arch with 35% carbamide peroxide, using several applications per day of 22% carbamide peroxide, and bleaching both arches simultaneously with 22% carbamide peroxide. The recommendation is to avoid using concentrations higher than 10% carbamide peroxide when one performs external bleaching. We advocate a selective use of external tooth bleaching based on high ethical standards and professional judgment. PMID:12907697

Dahl, J E; Pallesen, U

2003-01-01

308

Functional constraints on tooth morphology in carnivorous mammals  

PubMed Central

Background The range of potential morphologies resulting from evolution is limited by complex interacting processes, ranging from development to function. Quantifying these interactions is important for understanding adaptation and convergent evolution. Using three-dimensional reconstructions of carnivoran and dasyuromorph tooth rows, we compared statistical models of the relationship between tooth row shape and the opposing tooth row, a static feature, as well as measures of mandibular motion during chewing (occlusion), which are kinetic features. This is a new approach to quantifying functional integration because we use measures of movement and displacement, such as the amount the mandible translates laterally during occlusion, as opposed to conventional morphological measures, such as mandible length and geometric landmarks. By sampling two distantly related groups of ecologically similar mammals, we study carnivorous mammals in general rather than a specific group of mammals. Results Statistical model comparisons demonstrate that the best performing models always include some measure of mandibular motion, indicating that functional and statistical models of tooth shape as purely a function of the opposing tooth row are too simple and that increased model complexity provides a better understanding of tooth form. The predictors of the best performing models always included the opposing tooth row shape and a relative linear measure of mandibular motion. Conclusions Our results provide quantitative support of long-standing hypotheses of tooth row shape as being influenced by mandibular motion in addition to the opposing tooth row. Additionally, this study illustrates the utility and necessity of including kinetic features in analyses of morphological integration. PMID:22899809

2012-01-01

309

A 3-year prospective multicenter follow-up report on the immediate and delayed-immediate placement of implants.  

PubMed

A total of 264 implants was placed in 143 patients using different immediate or delayed-immediate implant placement techniques in 12 different centers participating in a prospective multicenter study. The reason for tooth extraction was evaluated; bone quality and quantity were classified; socket depths were registered; and data on implant type, size, and position were collected. One hundred thirty-nine suprastructures were placed on 228 implants in 126 patients. A follow-up evaluation was done on 125 patients after 1 year of loading and on 107 patients after 3 years of loading. Clinical parameters (bleeding or not bleeding, pocket depth, and implant mobility) were evaluated after 1 and 3 years, and the marginal bone level after 1 year of loading was measured on radiographs. Clinical comparisons were performed to evaluate implant loss in relation to implant type, size, position, bone quality and quantity, socket depth, reason for tooth extraction, and placement method. In addition, life table analysis was done for cumulative implant survival rates. There was no clinical difference with respect to socket depth or when comparing the different placement methods. A higher failure rate was found for short implants in the posterior region of the maxilla and when periodontitis was cited as a reason for tooth extraction. Mean marginal bone resorption from the time of loading to the 1-year follow-up was 0.8 mm in the maxilla and 0.5 mm in the mandible. Over a period of 3 years, the implant survival rate was 92.4% in the maxilla and 94.7% in the mandible. PMID:10212537

Grunder, U; Polizzi, G; Goené, R; Hatano, N; Henry, P; Jackson, W J; Kawamura, K; Köhler, S; Renouard, F; Rosenberg, R; Triplett, G; Werbitt, M; Lithner, B

1999-01-01

310

Surface modification of sapphire by ion implantation  

SciTech Connect

The range of microstructures and properties of sapphire (single crystalline Al{sub 2}O{sub 3}) that are produced by ion implantation are discussed with respect to the implantation parameters of ion species, fluence, irradiation temperature and the orientation of the ion beam relative to crystallographic axes. The microstructure of implanted sapphire may be crystalline with varying concentrations of defects or it may be amorphous perhaps with short-range order. At moderate to high fluences, implanted metallic ions often coalesce into pure metallic colloids and gas ions form bubbles. Many of the implanted microstructural features have been identified from studies using transmission electron microscopy (TEM), optical spectroscopy, Moessbauer spectroscopy, and Rutherford backscattering-channeling. The chemical, mechanical, and physical properties reflect the microstructures.

McHargue, C.J.

1998-11-01

311

Increased Crown-To-Implant Ratio May Not Be a Risk Factor for Dental Implant Failure under Appropriate Plaque Control  

PubMed Central

Objective The aim of this study was to evaluate whether increased crown-to-implant (C/I) ratio influences implant stability or not under proper healthy control of peri-implant mucosa. The hypothesis of this study is that implant stability can be maintained despite High C/I, under appropriate plaque control. Materials and Methods Five male Beagle-Labrador hybrid dogs (2 years old) were used. Their bilateral mandibular premolar extraction was performed. After allowing 12 weeks for bone healing, 3 types of vertical marginal bone loss were simultaneously prepared randomly. Then, 30 titanium implants were placed in the edentulous areas and defined as High C/I, Mid C/I and Low C/I groups. This time point was designated as the baseline (0 Week). Twelve weeks after implant placement, metal superstructures were cemented to the implants and an occlusal plate was set at the opposite side. At the same time, Calcein green was injected for remodeling evaluation. Implants were loaded by feeding the dogs a hard pellet diet. Tooth brushing was performed 5 days per week during the study to maintain healthy peri-implant mucosa. Twenty-four weeks following implant placement, the interface structure was evaluated clinically, radiologically, and histologically. Result Implant stability quotient (ISQ) increased with time in all 3 groups, without any significant correlation with the C/I value (p>0.05). Moreover, mean marginal bone loss adjacent around implants in all 3 groups ranged between 0.11 and 0.19 mm, with no significant difference (p>0.05). Many fluorescence-labeled bones are shown in the High C/I group. It is considered that high remodeling activity prevent marginal bone loss in the High C/I group and this may provide favorable implant stability under proper plaque control. Conclusion These findings suggest that increased C/I may not be a risk factor for implant failure if the peri-implant mucosa is kept healthy, as was the case in this animal model. PMID:23737960

Okada, Shinsuke; Koretake, Katsunori; Miyamoto, Yasunari; Oue, Hiroshi; Akagawa, Yasumasa

2013-01-01

312

Psychological effects of permanently implanted false teeth: A 2-year follow-up and comparison with dentate patients  

Microsoft Academic Search

The treatment of patients who have suffered total tooth loss (edentulism) has always posed many problems in dental care, since removable dentures cannot restore function completely and can often result in pain and mouth ulcers. An important recent advance is the development of “osseointegrated implants”. This technique involves the insertion of titanium screws into the jawbone and the denture is

Gerry Kent; Richard Johns

1993-01-01

313

Soft tissue dehiscence coverage around dental implants following an acellular dermal matrix allograft: a case report.  

PubMed

Acellular dermal matrix allograft (ADMA) is an alternative to a free gingival graft for keratinized tissue augmentation and root coverage. Soft tissue dehiscence is one of the major complications that can occur after replacing a missing tooth with a dental implant; it can lead to esthetic problems and have a negative impact on the long-term success of the implant. Soft tissue dehiscence coverage is not as predictable around dental implants as it is on root surfaces. This article describes a case involving soft tissue dehiscence, in which an ADMA was used to increase the width of keratinized mucosa around an implant-supported prosthesis, resulting in complete implant surface coverage due to the phenomenon of creeping attachment. PMID:24983177

Ayobianmarkazi, Nader

2014-01-01

314

Assessment of Tooth Structure using an Alternative Electrical Bioimpedance Spectroscopy Method.  

PubMed

In the past few years bioimpedance has been used in many applications in dentistry, such as estimating the length of root canals and the physical properties of enamel. Despite the significant number of studies using bioimpedance to investigate the dental structure, many of them use only the real component of bioimpedance, i.e., the resistance, disregarding the information provided by the imaginary one, i.e., the reactance. Moreover, in different studies that investigate both parts of bioimpedance, the data are obtained by using single frequency or multifrequency methods based on sinusoidal sweep. The aim of this study was to investigate the use of an alternative bioimpedance spectroscopy (BIS) method based on step response in the assessment of tooth structure. To test the feasibility of the studied method we performed in vitro experiments that considered the successive removal of enamel layers of 22 healthy teeth, the accomplishment of the BIS method, and the estimate of bioimpedance parameter that were associated with the changes in the tooth structure. To deal with the variability of bioimpedance parameters a dental health index (DHI) is proposed. The findings include the behavior of bioimpedance parameters of intact teeth, as well as those associated with the successive removal of the enamel layer, and indicate that DHI is sensitive enough to detect changes of the enamel layer. The results point to the feasibility of the studied BIS method in evaluating tooth structure and that it might be used to assess dental health. PMID:25140720

Morais, Andréa Pereira; Pino, Alexandre Visintainer; Souza, Marcio Nogueira

2014-04-01

315

Adhesion to tooth structure: a critical review of "micro" bond strength test methods.  

PubMed

The objective of this paper is to critically review the literature regarding the mechanics, geometry, load application and other testing parameters of "micro" shear and tensile adhesion tests, and to outline their advantages and limitations. The testing of multiple specimens from a single tooth conserves teeth and allows research designs not possible using conventional 'macro' methods. Specimen fabrication, gripping and load application methods, in addition to material properties of the various components comprising the resin-tooth adhesive bond, will influence the stress distribution and consequently, the nominal bond strength and failure mode. These issues must be understood; as should the limitations inherent to strength-based testing of a complicated adhesive bond joining dissimilar substrates, for proper test selection, conduct and interpretation. Finite element analysis and comprehensive reporting of test conduct and results will further our efforts towards a standardization of test procedures. For the foreseeable future, both "micro" and "macro" bond strength tests will, as well as various morphological and spectroscopic investigative techniques, continue to be important tools for improving resin-tooth adhesion to increase the service life of dental resin-based composite restorations. PMID:20045179

Armstrong, Steve; Geraldeli, Saulo; Maia, Rodrigo; Raposo, Luís Henrique Araújo; Soares, Carlos José; Yamagawa, Junichiro

2010-02-01

316

Effect of zinc ions on improving implant fixation in osteoporotic bone.  

PubMed

The application of titanium (Ti) and its alloys in tooth restoration and joint replacement for aged patients with unfavorable conditions is gaining popularity. Therefore, strategies aiming at improving the fixation of Ti-based implants are worth investigating. This study was designed to observe whether modification of Ti implants by zinc (Zn) could enhance the fixation capability in osteoporotic bone. Two kinds of implants, hydroxyapatite (HA) coated Ti and Zn-incorporated HA (ZnHA) coated Ti, were inserted into the femoral metaphysis longitudinally in ovariectomized (OVX) rats. Specimens were harvested and subjected to double fluorescence labeling examination at week 6 after surgery. At week 12, samples were evaluated with histomorphometry, micro-CT (?CT) analysis and biomechanical test. Compared to the HA coated implants, ZnHA coating improved mineral apposition rate (MAR) of peri-implant bone, which was revealed by double fluorescence labeling; bone area ratio (BA) and bone-to-implant contact (BIC) were also higher for the latter group by histomorphometry. ?CT images suggested that more bone mass was formed around the ZnHA coated implants as compared to the HA coated implants. Biomechanical push-out test showed that the ZnHA coated implants demonstrated higher strength of osseointegration than the HA group. The current study suggested that Zn ions could enhance bone formation and improve implant fixation in OVX rats. PMID:23971976

Li, Xudong; Li, Yunfeng; Peng, Shengcheng; Ye, Bin; Lin, Wei; Hu, Jing

2013-01-01

317

Clinical X-Ray Image Based Tooth Decay Diagnosis using SVM  

Microsoft Academic Search

Automatic tooth decay diagnosis achieved the satisfying results on the extracted tooth diagnosis by rule-based system and Artificial Neural Network (ANN). This paper, focusing on clinical tooth decay detection, introduces a Support Vector Machine (SVM) based diagnosis method. For comparison, an additional back propagation neural network (BPNN) tooth decay diagnosis experiment is reported. Comparative results indicate that SVM based method

Wei Li; Wei Kuang; Yun Li; Yu-Jing Li; Wei-Ping Ye

2007-01-01

318

ORIGINAL ARTICLE Force modeling for tooth preparation in a dental training system  

E-print Network

Tooth preparation is the process of re-shaping a decayed tooth to restore it. The shapeORIGINAL ARTICLE Force modeling for tooth preparation in a dental training system Guanyang Liu Ã?-Verlag London Limited 2008 Abstract Feedback force is very important for novices to simulate tooth preparation

319

Irregular tooth spacing reduces roller cone bit tracking problems  

SciTech Connect

On tungsten carbide insert bits, irregularly spaced teeth can help stop tracking problems, leading to increased penetration rates and longer bit runs. Tracking, which occurs when teeth fall into the craters formed during previous bit rotations, severely affects the performance of roller cone rock bits. The tracking tendencies of tungsten carbide insert (TCI) bits are generally considered once the bit is built and tested, rather than during the design process. Once tracking is initiated, crater depth quickly reaches the full projection of the teeth, bringing the cone steel in contact with the rock. This tracking increases the contact area while reducing contact stresses beneath the inserts. Tracking increases the likelihood that neighboring rows of cutters will line up on the hole bottom, forcing the bit to rotate about a point other than its geometric center. This phenomenon is termed off-center rotation or forward whirl. Off-center rotation produces rings of uncut bottom and a further reduction in contact stresses. This article covers laboratory and field data used in the development and validation of a proprietary algorithm that determines the optimal tooth spacing to eliminate tracking. This study confirms that an algorithm can be applied effectively in the roller cone bit design process to improve coverage of the rock surface during drilling. In addition, these laboratory tests improve the understanding of a single gear-like wheel, a key to understanding total bit behavior.

Kenner, J.V. [Hughes Christensen Co., Houston, TX (United States); Boylan, T.P. [Transatlantic Technical Services, Houston, TX (United States)

1996-05-13

320

Osseointegrated dental implants in growing children: a literature review.  

PubMed

Edentulism is usually associated with the aging patient. However, total or partial tooth loss also affects young individuals, mainly as a result of trauma, decay, anodontia, or congenital and acquired jaw defects involving the alveolar processes. For elderly patients, the use of oral implants has become an accepted treatment modality for edentulism, and most of today's knowledge regarding implants is based on such practice. There has been hesitation to perform implant therapy for growing children; hence, few children to date have been provided with implant-supported construction. Consequently, little is known about the outcome of the osseointegration procedure in young patients, and until now, only a limited number of case presentations have been reported. This article reviews the current literature to discuss the use of dental implants in growing patients and the influence of maxillary and mandibular skeletal and dental growth on the stability of those implants. The literature review was performed through Science Direct, Wileys Blackwell Synergy, PubMed, Google, Embase, Medknow publications, and Springer for references published from 1963 to 2011. It is recommended to wait for the completion of dental and skeletal growth, except for severe cases of ectodermal dysplasia. PMID:22214484

Mankani, Nivedita; Chowdhary, Ramesh; Patil, Brijesh A; Nagaraj, E; Madalli, Poornima

2014-10-01

321

12. Interior view showing main section, mezzanine and saw tooth ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Interior view showing main section, mezzanine and saw tooth truss roof with skylight, looking west. - College Heights Lemon Packing House, 519-532 West First Street, Claremont, Los Angeles County, CA

322

Silica nanoparticles to polish tooth surfaces for caries prevention.  

PubMed

Although silica particles have been used for tooth polishing, polishing with nanosized particles has not been reported. Here we hypothesize that such polishing may protect tooth surfaces against the damage caused by cariogenic bacteria, because the bacteria can be easily removed from such polished surfaces. This was tested on human teeth ex vivo. The roughness of the polished surfaces was measured with atomic force microscopy (AFM). A considerably lower nanometer-scale roughness was obtained when silica nanoparticles were used to polish the tooth surfaces, as compared with conventional polishing pastes. Bacterial attachment to the dental surfaces was studied for Streptococcus mutans, the most abundant cariogenic bacteria. We demonstrated that it is easier to remove bacteria from areas polished with silica nanoparticles. The results demonstrate the advantage of using silica nanoparticles as abrasives for tooth polishing. PMID:18809755

Gaikwad, R M; Sokolov, I

2008-10-01

323

Neuregulin-1 alleviates Charcot-Marie-Tooth disease in rats.  

PubMed

Disrupted differentiation of Schwann cells contributes to axonal loss in a rat model of Charcot-Marie-Tooth 1A neuropathy. Early neuregulin-1 treatment promotes Schwann cell differentiation, preserves axons and restores nerve function in this model. PMID:25198045

Martini, Rudolf

2014-09-01

324

Implant success!!!.....simplified.  

PubMed

The endeavor towards life-like restoration has helped nurture new vistas in the art and science of implant dentistry. The protocol of "restoration-driven implant placement" ensures that the implant is an apical extension of the ideal future restoration and not the opposite. Meticulous pre-implant evaluation of soft and hard tissues, diagnostic cast and use of aesthetic wax-up and radiographic template combined with surgical template can simplify the intricate roadmap for appropriate implant treatment.By applying the harmony of artistic skill, scientific knowledge and clinical expertise, we can simply master the outstanding implant success in requisites of aesthetics, phonetics and function. PMID:20376237

Luthra, Kaushal K

2009-01-01

325

Norplant implants.  

PubMed

This letter to the editor is in response to 3 articles on the use of the Norplant implant contraceptive in The Indian Health Service (IHS) Provider. Norplant and the FDA-approved Depo-Provera now expand contraceptive options for women. All IHS and 638 sites might be able to offer both options. Several of the authors expressed concern regarding decreased Norplant effectiveness in heavier patients. Norplant is still more effective than any other currently available reversible contraceptive in the US at all weights. Many experts feel the current silastic capsule provides adequate hormone levels even in heavier women. The Crow Service Unit has initiated their Norplant program, although the Wyeth consent form seems unnecessarily extensive. The Albuquerque Service Unit consent form simply describes the procedure and confirms that patients have read and understand the fact sheet. The theoretical risk of thromboembolism is vastly outweighed by the potential benefit of reliable contraception in high risk alcoholic women, except perhaps in women with severe liver disease. While Norplant is expensive, programs need to consider the actual cost of a pregnancy, potential complications, and the financial and social costs of unintended pregnancy. For those in difficult straits, the manufacturer has set up a foundation for obtaining Norplant free of charge. Depo-Provera comes in a 150 mg dose vial that is given every 3 months. The mean time to ovulation is 4.5 months from the last dose. The adverse reaction spectrum is similar to Norplant as they are both progesterone-related agents. Providers and clinics should reduce barriers to family planning by giving out more pill packs at a time; letting adolescents who wish to delay their first pelvic exam have 3 months of pills without an exam; making condoms available in exam rooms rather than through pharmacy prescriptions; and increasing patient accessibility to the morning-after pill. PMID:12288838

Henley, E

1993-06-01

326

Branched afferent nerves supplying tooth-pulp in the cat.  

PubMed Central

1. Recordings have been made from nerve terminals in canine and third incisor teeth of cats. 2. Ninety-three tooth-pulp units in ten cats could be excited either by mechanical or electrical stimulation of adjacent mucous membrane or by electrical stimulation of the pulp of a nearby tooth. 3. Section of the trigeminal nerve centrally did not abolish these responses. 4. Results for twelve out of thirteen units tested with collision techniques indicated that the nerves were branched. PMID:671361

Lisney, S J; Matthews, B

1978-01-01

327

3D-Geomorphometrics tooth shape analysis in hypodontia  

PubMed Central

Assessment of tooth morphology is an important part of the diagnosis and management of hypodontia patients. Several techniques have been used to analyze tooth form in hypodontia patients and these have shown smaller tooth dimensions and anomalous tooth shapes in patients with hypodontia when compared with controls. However, previous studies have mainly used 2D images and provided limited information. In the present study, 3D surface-imaging and statistical shape analysis were used to evaluate tooth form differences between hypodontia and control patients. Eighteen anatomical landmarks were recorded on the clinical crown of the lower left first permanent molar of 3D scanned study models of hypodontia and control subjects. The study sample group comprised of 120 hypodontia patients (40 mild, 40 moderate, and 40 severe hypodontia patients) and 40 age- and sex-matched controls. Procrustes coordinates were utilized to scale and superimpose the landmark coordinate data and then were subjected to principal component analysis (PCA). Subsequently, differences in shape as well as size were tested statistically using allometric analysis and MANOVA. Significant interaction was found between the two factor variables “group” and “sex” (p < 0.002). Overall expected accuracies were 66 and 56% for females and males, respectively, in the cross-validated discriminant-analysis using the first 20 PCs. Hypodontia groups showed significant shape differences compared with the control subjects (p < 0.0001). Significant differences in tooth crown shape were also found between sexes (p < 0.0001) within groups. Furthermore, the degree of variation in tooth form was proportional to the degree of the severity of the hypodontia. Thus, quantitative measurement of tooth shape in hypodontia patients may enhance the multidisciplinary management of those patients. PMID:24795649

Al-Shahrani, Ibrahim; Dirks, Wendy; Jepson, Nicholas; Khalaf, Khaled

2014-01-01

328

Evaluation of Steam Turbines Triangular Tooth on Stator Labyrinth Seal  

E-print Network

.4. Association of discharge coefficient with Re at different tooth location (compressible flow, case 11 ). ........................................... 84? Fig. 4.5. Streamlines and axial velocity distribution in four teeth... .......................... 85? Fig. 4.6. Discharge coefficient of the seal with four teeth ...................................... 86? xvi Fig. 4.7. Deviation of Cd values at different tooth position for Re ........................ 87? Fig. 4.8. Association of Cd...

Tanvir, Hossain Ahmed

2012-07-16

329

Is there a link between ovarian cancer and tooth agenesis?  

PubMed

An epidemiologic study from the year 2008 found a highly significant increase of congenital tooth agenesis in women with ovarian cancer suggesting that a common genetic etiology may predispose women to both conditions. The finding was reminiscent of a previously described family harboring an AXIN2 mutation which could be shown to segregate with both the tooth agenesis and the predisposition to colon cancer transmitted in this family. Since tooth agenesis as a marker for susceptibility to ovarian cancer would be of great relevance to both oncologists and women with inborn missing teeth, the relationship between the two disorders requires a thorough assessment. We examined DNA samples from the ovarian cancer patients who participated in the original study, to look for a possible genetic connection between their ovarian malignancies and tooth agenesis. MSX1, PAX9, AXIN2, EDA, WNT10A, BARX and BRCA1 genes were selected for sequence analysis as they may cause tooth agenesis, are expressed in the female reproductive system, and/or are involved in tumorigenesis in general or specifically in the ovary. Our study revealed evidence that one half of the dually affected patients had an independent causation of the two conditions, thus reducing the previously estimated ovarian cancer risk for women with congenital tooth agenesis quite significantly. PMID:24631698

Bonds, John; Pollan-White, Sarah; Xiang, Lilin; Mues, Gabriele; D'Souza, Rena

2014-04-01

330

Urinary incontinence - injectable implant  

MedlinePLUS

Injectable implants are injections of material into the urethra to help control urine leakage ( urinary incontinence ) caused by a ... into the tissue next to the sphincter. The implant procedure is usually done in the hospital. Or ...

331

ESR of CO2- in X-irradiated tooth enamel and A-type carbonated apatite.  

PubMed

Using both low microwave power and weak magnetic field modulation, we have shown that the asymmetric signal arising in X-irradiated tooth enamel as well as in A-type carbonated apatite exposed to X-rays or to excited oxygen has an orthorhombic character and must be attributed to CO2-. Effectively, the mean values found for the three g-tensor components are comparable to those quoted for this defect in single-crystal specimens of calcite and sodium formate. PMID:6260310

Bacquet, G; Truong, V Q; Vignoles, M; Trombe, J C; Bonel, G

1981-01-01

332

Use of ultrasound Doppler to determine tooth vitality in a discolored tooth after traumatic injury: its prospects and limitations  

PubMed Central

When a tooth shows discoloration and does not respond to the cold test or electric pulp test (EPT) after a traumatic injury, its diagnosis can be even more difficult due to the lack of proper diagnostic methods to evaluate its vitality. In these case reports, we hope to demonstrate that ultrasound Doppler might be successfully used to evaluate the vitality of the tooth after trauma, and help reduce unnecessary endodontic treatments. In all three of the present cases, the teeth were discolored after traumatic injuries and showed negative responses to the cold test and EPT. However, they showed distinctive vital reactions in the ultrasound Doppler test during the whole observation period. In the first case, the tooth color returned to normal, and the tooth showed a positive response to the cold test and EPT at 10 wk after the injury. In the second case, the tooth color had returned to its normal shade at 10 wk after the traumatic injury but remained insensitive to the cold test and EPT. In the third case, the discoloration was successfully treated with vital tooth bleaching. PMID:24516833

Cho, Yong-Wook

2014-01-01

333

Shading of ceramic crowns using digital tooth shade matching devices.  

PubMed

In the 1990s, there was great optimism due to the development of devices for measuring tooth shade. The frequently not so simple, visual determination of the shade of a tooth was to be done with the aid of a device which recognizes the shade and describes it accurately by reference to a color chart. However, the skepticism towards such devices was also great. It is known that the color effect frequently differs strongly when comparing a tooth from the shade guide with a metal ceramic crown, despite identical shade designation. Anyone who considers visual shade determination to be inadequate and places his hopes in digital shade matching devices will be disappointed. It is the shade-generating structures of the metal ceramic and frequently of the veneer layers that turn out to be too thin which, despite correct shade selection, cause a different color perception. Such problems have been reduced decisively with the development of fracture-proof hard porcelain caps (Vita In-Ceram) with optical characteristics similar to teeth. In addition, the Vita System 3D-Master tooth shade system developed in 1998 by Vita in cooperation with Dr. Hall from Australia, leads the practitioner to a better understanding of the primary tooth shade characteristics of "brightness (value)", "color intensity (chroma)" and "color (wave length of the visible light, hue)". These two innovations allow a more accurate estimate of the basic shade of a natural tooth (reference tooth) and the imitation in the laboratory of its natural, shade-generating structures. If digital shade measurement supplements the visual shade estimate, then a further improvement can be expected--especially in the recognition of the basic shade. Qualitative descriptions of subjective shade measurement of a natural tooth and of its imitation in the dental laboratory by ceramics can be found frequently in professional journals and publications. With digital tooth shade matching devices, which apart from the color code of the color chart also reproduce exact, colorimetric values, such work processes can be recorded quantitatively and objectively. Reports about this type of controlled shade determination and generation are found rarely in the literature, which is surprising in view of the large number of tooth shade matching devices and dental ceramic systems available. In the present paper, the influence of the individual ceramic layers on color perception is measured and described under standardized conditions. The creation of the basic shade as it results from the composition of the various ceramic layers is traced with a spectrophotometer. The Vita In-Ceram Alumina infiltration ceramic and the VitaVM7 veneer ceramic were selected as the ceramic system. MHT-SpectroShade and Vita Easyshade were used as shade matching devices. PMID:16201397

Baltzer, A; Kaufmann-Jinoian, V

2005-04-01

334

A no bleed implant  

Microsoft Academic Search

Breast implants have evolved from the original saline-filled, smooth-surfaced silicone rubber bag to silicone gel-filled smooth-walled sacs to a combination of a silicone gel-filled bag within a saline-filled sac, and, most recently, a reversed, double-lumen implant with a saline bag inside of a gel-filled bag. Texture-surfaced implants were first used in 1970 when the standard silicone gelfilled implant was covered

Robert A. Ersek; Jose Alberto Navarro; Dora Zsofia Nemeth; George Sas

1993-01-01

335

Implantable Heart Aid  

NASA Technical Reports Server (NTRS)

CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

1984-01-01

336

Experimental investigation of fatigue behavior of spur gear in altered tooth-sum gearing  

NASA Astrophysics Data System (ADS)

This paper deals with the contact stress, power loss, and pitting of spur gear tooth in altered tooth-sum gearing for a tooth-sum of 100 teeth when altered by ±4% tooth-sum. Analytical and experimental methods were performed to investigate and compare the altered tooth-sum gearing against the standard tooth-sum gearing. The experiments were performed using a power recirculating type test rig. The tooth loads for the experimental investigations were determined considering the surface durability of gears. A clear picture of the surface damage was obtained using a scanning electron microphotograph. The negative alteration in the tooth-sum performed better than the positive alteration in a tooth-sum operating between specified center distances.

Sachidananda, H. K.; Gonsalvis, Joseph; Prakash, H. R.

2012-09-01

337

N-ion implantation assisted by preparative and closing implantation for surface modification of tool steel  

NASA Astrophysics Data System (ADS)

The study aims at investigating the effect of auxiliary preparative and closing implantations in hardened tool steels on surface tribology modification. Samples of a martensitic tool steel, SKD11, are triply implanted with ions of N or Ar at higher energies, N at the normal energy, and N, BF and CO 2 at lower energies. The ion implantations result in dramatic increases of hardness and wear resistance to the samples in comparison with single N-ion implantation and double ion implantation. Analysis of ion depth profiles and surface compositions and microstructures is performed to reveal the mechanisms. It can be concluded that the improvement of the mechanical properties can be attributed to the deepening in the ion penetration and the forming of compound covers at the near surface region.

Vilaithong, T.; Yu, L. D.; Vichaisirimongkol, P.; Rujijanagul, G.; Sonkaew, T.

1999-01-01

338

Magnetism in Ar-implanted ZnO  

NASA Astrophysics Data System (ADS)

ZnO single crystals were implanted with Ar ions with an energy of 100 keV and different fluences. Ferromagnetic behaviour is observed at room temperature after implantation. This behaviour is suppressed after consecutive annealings at 400 and 500 °C. Although trace transition metal impurities have been identified in the virgin samples, it is shown that they cannot account for the observed magnetic behaviour that is assigned to the presence of implantation-induced lattice defects.

Borges, R. P.; da Silva, R. C.; Magalhães, S.; Cruz, M. M.; Godinho, M.

2007-11-01

339

Trends in Cochlear Implants  

PubMed Central

More than 60,000 people worldwide use cochlear implants as a means to restore functional hearing. Although individual performance variability is still high, an average implant user can talk on the phone in a quiet environment. Cochlear-implant research has also matured as a field, as evidenced by the exponential growth in both the patient population and scientific publication. The present report examines current issues related to audiologic, clinical, engineering, anatomic, and physiologic aspects of cochlear implants, focusing on their psychophysical, speech, music, and cognitive performance. This report also forecasts clinical and research trends related to presurgical evaluation, fitting protocols, signal processing, and postsurgical rehabilitation in cochlear implants. Finally, a future landscape in amplification is presented that requires a unique, yet complementary, contribution from hearing aids, middle ear implants, and cochlear implants to achieve a total solution to the entire spectrum of hearing loss treatment and management. PMID:15247993

Zeng, Fan-Gang

2004-01-01

340

Tooth loss, chewing ability and quality of life  

PubMed Central

Objectives: The aim of this study was to observe the tooth loss over age in a sample of Brazilian patients and analyze their ability to chew, relating it to how much is the loss of oral function impact over the quality of life (QoL). Materials and Methods: This is a single center, observational study and the data were collected through clinical examination followed of questionnaires to obtain sociodemographic information, the ability to chew (through the index of chewing ability [ICA]) and QoL (through Oral Health Impact Profile, OHIP-14). Results: The sample was composed by 171 random volunteers with mean age of 47 (SD 15.2). Low number of natural teeth was associated with an increase of age (Spearman's rho correlation coefficient-0.7, P < 0.001, 2-tailed) and chew disability (ICA: chew's ability vs. disability) (Mann-Whitney U-Test, P < 0.001). Chew disability showed a negative impact over the QoL (overall OHIP; Mann-Whitney U Test P < 0.001) and in five of seven OHIP domains (Functional Limitation, Physical Pain, Psychological Discomfort, Physical Disability, Psychological Disability). Age over than 40 years, was also associated with chewing disability (Pearson Chi-Square P < 0.001) and poorer QoL (Mann-Whitney U test P = 0.01). Conclusion: This study observed that the chewing disability produces a significant and negative impact over oral-health related QoL and both, poor QoL and chewing disability are related with the decrease of the number of natural teeth. PMID:23633796

Bortoluzzi, Marcelo Carlos; Traebert, Jefferson; Lasta, Renata; Da Rosa, Thaiany Naila; Capella, Diogo Lenzi; Presta, Andreia Antoniuk

2012-01-01

341

Increased preventive practices lead to greater tooth retention.  

PubMed

Prior research has rarely examined the impact of ADA-recommended preventive practices on tooth retention. We hypothesized that better oral hygiene leads to increased tooth retention. We examined the association of cross-sectional and long-term assessments of preventive practices, as well as various combinations of hygiene practices, with tooth retention. Among 736 male participants in the VA Dental Longitudinal Study, we utilized cross-sectional and longitudinal self-reports of toothbrushing, dental floss use, annual prophylaxis, and combinations of such behaviors, and examined their association with clinically assessed numbers of teeth. Baseline and long-term hygiene behaviors (except brushing) were associated with an increased baseline number of teeth and decreased subsequent tooth loss. Use of multiple hygiene behaviors was associated with greater tooth retention, cross-sectionally and longitudinally. Adherence to ADA recommendations for preventive care leads to better oral health, and consistently practicing preventive behaviors over the long term confers greater benefits than doing so over the short term. PMID:12598553

Kressin, N R; Boehmer, U; Nunn, M E; Spiro, A

2003-03-01

342

The development of complex tooth shape in reptiles.  

PubMed

Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development. PMID:24611053

Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S

2014-01-01

343

Performance of laser fluorescence at tooth surface and histological section.  

PubMed

This study aimed to evaluate a laser fluorescence device (the DIAGNOdent) and a visual classification system (ICDAS-II) for occlusal caries diagnosis. It also aimed to determine whether fluorescence measurements taken at the tooth surface correlate with the fluorescence measurements taken within the body of the lesion. The occlusal surfaces of 100 extracted permanent teeth were examined using ICDAS-II and DIAGNOdent (LF-tooth). Serial sections were made and lesion depth was assessed histologically. DIAGNOdent readings were also taken from the sections (LF-section). There were significant positive strong correlations between ICDAS-II and histology (r(S)?=?0.71) and LF-section and histology (r(S)?=?0.70), and only moderate correlations between LF-tooth and histology (r(S)?=?0.51) and LF-tooth and LF-section (r(S)?=?0.60). Diagnostic accuracy for ICDAS-II was generally better than for LF-tooth. While the DIAGNOdent device provides an objective reading for detection and monitoring of carious lesions, using the cut-off ranges previously suggested leads to inferior performance. PMID:20221781

Jablonski-Momeni, Anahita; Ricketts, David N J; Rolfsen, Stefanie; Stoll, Richard; Heinzel-Gutenbrunner, Monika; Stachniss, Vitus; Pieper, Klaus

2011-03-01

344

The effect of light-activation sources on tooth bleaching  

PubMed Central

Vital bleaching is one of the most requested cosmetic dental procedures asked by patients who seek a more pleasing smile. This procedure consists of carbamide or hydrogen peroxide gel applications that can be applied in-office or by the patient (at-home/overnight bleaching system). Some in-office treatments utilise whitening light with the objective of speeding up the whitening process. The objective of this article is to review and summarise the current literature with regard to the effect of light-activation sources on in-office tooth bleaching. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2003 to 2013 searching for articles relating to effectiveness of light activation sources on in-office tooth bleaching. This study found conflicting evidence on whether light truly improve tooth whitening. Other factors such as, type of stain, initial tooth colour and subject age which can influence tooth bleaching outcome were discussed. Conclusions: The use of light activator sources with in-office bleaching treatment of vital teeth did not increase the efficacy of bleaching or accelerate the bleaching.

Baroudi, Kusai; Hassan, Nadia Aly

2014-01-01

345

Monte Carlo modeling of human tooth optical coherence tomography imaging  

NASA Astrophysics Data System (ADS)

We present a Monte Carlo model for optical coherence tomography (OCT) imaging of human tooth. The model is implemented by combining the simulation of a Gaussian beam with simulation for photon propagation in a two-layer human tooth model with non-parallel surfaces through a Monte Carlo method. The geometry and the optical parameters of the human tooth model are chosen on the basis of the experimental OCT images. The results show that the simulated OCT images are qualitatively consistent with the experimental ones. Using the model, we demonstrate the following: firstly, two types of photons contribute to the information of morphological features and noise in the OCT image of a human tooth, respectively. Secondly, the critical imaging depth of the tooth model is obtained, and it is found to decrease significantly with increasing mineral loss, simulated as different enamel scattering coefficients. Finally, the best focus position is located below and close to the dental surface by analysis of the effect of focus positions on the OCT signal and critical imaging depth. We anticipate that this modeling will become a powerful and accurate tool for a preliminary numerical study of the OCT technique on diseases of dental hard tissue in human teeth.

Shi, Boya; Meng, Zhuo; Wang, Longzhi; Liu, Tiegen

2013-07-01

346

Monte Carlo simulation for light propagation in 3D tooth model  

NASA Astrophysics Data System (ADS)

Monte Carlo (MC) simulation was implemented in a three dimensional tooth model to simulate the light propagation in the tooth for antibiotic photodynamic therapy and other laser therapy. The goal of this research is to estimate the light energy deposition in the target region of tooth with given light source information, tooth optical properties and tooth structure. Two use cases were presented to demonstrate the practical application of this model. One case was comparing the isotropic point source and narrow beam dosage distribution and the other case was comparing different incident points for the same light source. This model will help the doctor for PDT design in the tooth.

Fu, Yongji; Jacques, Steven L.

2011-03-01

347

An alternative multiple pontic design for a fixed implant-supported prosthesis.  

PubMed

In situations of moderate residual ridge resorption where multiple tooth replacement is needed, and where the patient desires a fixed implant-supported restoration, it is challenging to design a pontic-tissue interface. The semiconvex multiple pontic design described in this article, with its mucosal contact exerted with moderate pressure, is proposed to circumvent the problems encountered with the plaque accumulation, maintenance conditions, phonetics, and compromised esthetics frequently encountered in these patients. The use of a screw-retained, implant-supported restoration is also emphasized to allow for sufficient tissue contact during placement of the prosthesis and for prosthesis retrievability for maintenance or technical reasons. PMID:21889007

Del Castillo, Rafael; Ercoli, Carlo; Delgado, Juan Carlos; Alcaraz, Jaime

2011-09-01

348

Implant Supported Mandibular Overdenture: A Viable Treatment Option for Edentulous Mandible  

PubMed Central

The prosthetic management of the edentulous patient has long been a major challenge. Complete maxillary and mandibular dentures have been the traditional standard of care. However, most of the patients report problems adapting to their mandibular denture due to a lack of comfort, retention, stability and inability to masticate. Implant-supported overdentures have been a common treatment for edentulous patients for the past 20 years and predictably achieve good clinical results. Implant supported overdentures offer many practical advantages over conventional complete dentures and removable partial dentures. These include decreased bone resorption, reduced prosthesis movement, better esthetics, improved tooth position, better occlusion, increased occlusal function and maintenance of the occlusal vertical dimension. This article presents a design and fabrication technique of the implant-retained overdenture that uses four freestanding mandibular implants. PMID:24995252

Lambade, Pravin; Gundawar, Sham

2014-01-01

349

Endoscopic Removal of a Supernumerary Premolar in the Mandible during a Dental Implant Placement  

PubMed Central

The surgical removal of supernumerary teeth is necessary in some cases, especially before the commencement of any orthodontic or implant treatment procedure. In the mandibular supernumerary premolar, a more conservative approach is required because of the presence of complications associated with conventional surgery due to the close proximity of the said premolar to the alveolar inferior and mental nerves, and the need for bone conservation for implant placement. The endoscopic surgical approach has been used for the removal of the maxillary supernumerary tooth, impacted third molar, and implants. In this case report, we present an endoscopically assisted surgical technique for the removal of an unerupted supernumerary premolar in the mandible associated with a dental implant placement procedure. PMID:24772355

Beltran, Victor; Cantin, Mario; Fuentes, Ramon; Engelke, Wilfried

2014-01-01

350

Implant supported mandibular overdenture: a viable treatment option for edentulous mandible.  

PubMed

The prosthetic management of the edentulous patient has long been a major challenge. Complete maxillary and mandibular dentures have been the traditional standard of care. However, most of the patients report problems adapting to their mandibular denture due to a lack of comfort, retention, stability and inability to masticate. Implant-supported overdentures have been a common treatment for edentulous patients for the past 20 years and predictably achieve good clinical results. Implant supported overdentures offer many practical advantages over conventional complete dentures and removable partial dentures. These include decreased bone resorption, reduced prosthesis movement, better esthetics, improved tooth position, better occlusion, increased occlusal function and maintenance of the occlusal vertical dimension. This article presents a design and fabrication technique of the implant-retained overdenture that uses four freestanding mandibular implants. PMID:24995252

Lambade, Dipti; Lambade, Pravin; Gundawar, Sham

2014-05-01

351

Shadowing of lightly doped drain implants due to gate etch profiles and implanter configurations  

NASA Astrophysics Data System (ADS)

Shadowing of lightly doped drain (LDD) implants at the gate edge can cause shifts in effective electrical channel length (Leff), drive current (Ids) and transistor asymmetry. Process integration of gate etch and LDD implant processing and equipment in Motorola has led to the discovery of a unique type of implant shadowing. The increased vertical profile of the gate etch on modern single wafer etch systems obviously increases the potential to shadow implants and some amount of shadowing is not detrimental to the devices. In LDD processes which both the N-type and P-type LDD implants are masked separately, the gate etch profile and implant angle and rotation will determine the amount of shadowing for each transistor orientation. In processes that use a blanket N-LDD and a masked P-LDD adjusted to compensate for the N-dopant in the P-channel devices, an interaction between different implanter rotations has been shown to drastically increase the shadowing affects and leave uncompensated N-LDD dopant. It is necessary to carefully match the implant angles and rotations for proper performance of these LDD structures.

Henis, Neil B.; Abercrombie, David; Brownson, Rickey

1996-09-01

352

Amorphous clusters in Co implanted ZnO induced by boron pre-implantation  

SciTech Connect

We demonstrate the formation of superparamagnetic/ferromagnetic regions within ZnO(0001) single crystals sequently implanted with B and Co. While the pre-implantation with B plays a minor role for the electrical transport properties, its presence leads to the formation of amorphous phases. Moreover, B acts strongly reducing on the implanted Co. Thus, the origin of the ferromagnetic ordering in local clusters with large Co concentration is itinerant d-electrons as in the case of metallic Co. The metallic amorphous phases are non-detectable by common X-ray diffraction.

Potzger, K.; Shalimov, A.; Zhou, S.; Schmidt, H.; Mucklich, A.; Helm, M.; Fassbender, J.; Liberati, M.; Arenholz, E.

2009-02-09

353

Multidisciplinary Treatment Options of Tooth Avulsion Considering Different Therapy Concepts  

PubMed Central

Background: Avulsion of permanent front teeth is a rare accident, mostly affecting children between seven and nine years of age. Replanted and splinted, these teeth often develop inflammation, severe resorption or ankylosis affecting alveolar bone development and have to be extracted sooner or later. Objectives: The purpose of this study was to evaluate different therapy concepts to create a structured concept for the treatment of avulsions. Results: Based on existing therapy concepts, a concept for different initial conditions (dry time, age, growth, tooth, hard and soft tissues) was developed and is presented here. Conclusion: A great deal of research has been performed during recent years and guidelines for the management of avulsions have been published. With the help of this literature it is possible to identify the best treatment procedure for each tooth. Clinical Relevance: The prognosis of avulsed teeth can be improved by considering evidence-based therapy concepts. Resorption, ankylosis and tooth loss could be minimized. PMID:25352922

Kostka, Eckehard; Meissner, Simon; Finke, Christian H; Mandirola, Manlio; Preissner, Saskia

2014-01-01

354

Tooth agenesis patterns in bilateral cleft lip and palate.  

PubMed

Individuals with cleft lip and palate present significantly more dental anomalies, even outside the cleft area, than do individuals without clefts. Our aim was to evaluate the prevalence of tooth agenesis and patterns of hypodontia in a large sample of patients with complete bilateral cleft lip and palate (BCLP). Serial panoramic radiographs (the first radiograph was taken at 10.5-13.5 yr of age) of 240 patients with BCLP (172 male patients, 68 female patients) were examined. Third molars were not included in the evaluation. Agenesis of at least one tooth was present in 59.8% of patients. Upper laterals and upper and lower second premolars were missing most frequently. Using the tooth agenesis code (TAC), 52 different agenesis patterns were identified, of which simultaneous agenesis of 12, 22, 15, 25, 35, and 45 was the most frequent pattern. Nine of the 240 patients showed combined BCLP and oligodontia. PMID:20156264

Bartzela, Theodosia N; Carels, Carine E L; Bronkhorst, Ewald M; Rønning, Elisabeth; Rizell, Sara; Kuijpers-Jagtman, Anne Marie

2010-02-01

355

Assessing tooth color differences in digital facial portraits.  

PubMed

Although a large body of scientific literature shows that background color and luminance affect color perception, previous measurements of tooth color difference thresholds have not taken the effects of viewing context into account. The present study tested the hypothesis that differences in skin/gingival color influence individuals' judgments of tooth color differences. Perceptibility and acceptability thresholds were determined in 10 individuals using a signal detection paradigm. They evaluated 500 pseudo-random presentations of two facial portraits: an African-American and a Caucasian. These portraits varied trial-to-trial only in the direction (CIELAB +L*, +a*, or +b*) or magnitude of the color difference between a portrait's two central incisors. The individuals were significantly less sensitive to tooth color differences in the +L* direction in the Caucasian portrait than for any other combination of color direction or portrait type. Furthermore, comparable perceptibility and acceptability thresholds were generally not statistically significant from each other. PMID:20739690

Lindsey, D T; Wee, A G

2010-11-01

356

Peroxide-containing tooth whiteners: an update on safety.  

PubMed

The efficacy of peroxide-containing tooth whiteners has been well accepted; however, controversy concerning their safety has continued. Recently, a court ruling resulted in a ban on peroxide-containing tooth whiteners in the United Kingdom. While the decision was based on the classification of whiteners, there were issues with specious concerns about the safety, particularly carcinogenicity, of hydrogen peroxide (H2O2). This article reviews and discusses available scientific data on the carcinogenicity of H2O2 and consequently, their implications in the use of whiteners. An update on the effect of whiteners on the enamel surface is also included because controversial results were reported in recent studies. Based on current information, it is concluded that the proper use of dentist-monitored, at-home tooth whiteners containing 10% carbamide peroxide imposes no risk of carcinogenicity and does not cause irreversible damage to enamel. PMID:11908347

Li, Y

2000-01-01

357

Tooth crown morphogenesis and cytodifferentiations: candid questions and critical comments.  

PubMed

Teeth are probably meristic units and crown morphogenesis leads to tooth specific distribution of functional cells. Since heterodonty is derived from homodonty, one way to understand tooth morphogenesis would be to unravel the involved phenomena in homodont species and then to characterize the "put up job" of evolution leading to species specific dentitions with particular functional abilities. Interaction of paleontologists and developmental biologists should be initiated. My naive "developmental" point of view will illustrate only one facet of mouse tooth morphogenesis and cytodifferentiation. The main concern will be to try to discriminate between known facts and speculations, between hypotheses and anticipated or deduced certitudes, to call attention to conflicting data, to suggest some further investigations and to advocate the point of view that molecular interpretations should be founded on indisputable morphological data. PMID:7554904

Ruch, J V

1995-01-01

358

[Research on the development of image guided oral implant system].  

PubMed

In this paper is introduced an image guided oral implant system (IGOIS), including the 3D surface-model generation through Marching Cubes algorithm and large-scale triangular mesh simplification, the realization of pre-operative planning module with computer graphics and image processing technology, the non-invasive point-to-point registration with the fabrication of tooth-supported polymer resin templates and ICP algorithm, and the development of the real-time navigation system software by programming in VTK and VC+ +6.0. The experimental test for a patient's rapid prototype model shows that with the support of IGOIS, the precision achieved in the planning phase can be transferred to the patient so that the accuracy of the oral implant surgery under difficult conditions is improved. PMID:18610636

Chen, Xiaojun; Lin, Yanping; Wu, Yiqun; Wang, Chengtao

2008-04-01

359

Bilateral Cochlear Implants in Children: Localization Acuity Measured with Minimum  

E-print Network

- tal arc with a radius of 1.5 m. Stimuli were spondaic words recorded with a male voice. Stimulus. Minimum audible angle thresholds were mea- sured in the BI (cochlear implant cochlear im- plant cochlear implant) but not significantly different when listening with a single cochlear im- plant

Litovsky, Ruth

360

Cataract surgery combined with implantation of an artificial iris  

Microsoft Academic Search

We describe 6 patients who presented with cataract or aphakia and absent or nonfunctional irides. The etiologies included congenital aniridia, traumatic iris loss, and chronic mydriasis secondary to recurrent herpetic uveitis. In 5 eyes, a prosthetic iris was successfully implanted in combination with small incision cataract surgery. In 2 eyes, a single-piece iris diaphragm and optical lens was implanted. Artificial

Robert H Osher; Scott E Burk

1999-01-01

361

Generation of gear tooth surfaces by application of CNC machines  

NASA Technical Reports Server (NTRS)

This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

Litvin, F. L.; Chen, N. X.

1994-01-01

362

Tooth resorption part II - external resorption: Case series  

PubMed Central

External tooth resorption usually follows trauma to the periodontal ligament. It can be classified into five categories based on its clinical and histological manifestations. Calcium hydroxide has long been used as an intracanal medicament to slow down the resorption process due to its alkaline pH. A combination of both external and internal resorptions can also occur on the same tooth, making the management more complex. Five case reports of external resorption have been presented in this article along with pertinent review of literature. Successful management was possible in two cases, while extractions had to be advised in 3 cases due to advanced nature of the lesions. PMID:23716975

Fernandes, Marina; de Ataide, Ida; Wagle, Rahul

2013-01-01

363

Turner's tooth with unique radiographic presentation: a case report.  

PubMed

Hypoplasia--the result of a disruption in the enamel matrix formation process--causes a defect in the quality and thickness of enamel. Enamel formation is a complex and highly regulated process. Enamel defects have been associated with a broad spectrum of etiologies, including genetic, epigenetic, systemic, local, and environmental factors. An enamel defect in the permanent teeth caused by periapical inflammatory disease in the overlying primary tooth is referred to as Turner's tooth (also known as Turner's hypoplasia). This article presents a case of Turner's hypoplasia of the first mandibular premolar, with an unusual radiographic presentation. PMID:25184717

Lakshman, Anusha Rangare; Kanneppady, Sham Kishor; Castelino, Renita Lorina

2014-01-01

364

Impression techniques for implant dentistry  

Microsoft Academic Search

The object of making an impression in implant dentistry is to accurately relate an analogue of the implant or implant abutment to the other structures in the dental arch. This is affected by use of an impression coping which is attached to the implant or implant abutment. This impression coping is incorporated in an impression – much as a metal

S Jivraj; W Chee

2006-01-01

365

Longitudinal implant stability measurements based on resonance frequency analysis after placement in healed or regenerated bone.  

PubMed

Primary stability is an indicator of subsequent osseointegration of dental implants. However, few studies have compared the implant stability among anatomical regions and bone types; thus, not enough data exist regarding the stability of implants placed in regenerated bone (RB). The present study evaluated primary and long-term stability of implants placed in RB and non-regenerated healed bone (HB). A total of 216 screw cylinder implants were placed in 216 patients (98 in HB and 118 in RB, 6 [RB6, N = 68] or 12 [RB12, N = 50] months after tooth extraction). Implant stability was evaluated using resonance frequency analysis (RFA) measured at the time of implant placement (E1), at the time of loading (4 months after placement, E2), and 4 months after loading (E3). Various clinically relevant measurements were obtained, such as implant diameter, length, and location, as well as bone quality. At E1, implant location, bone quality, and experimental group significantly affected implant stability (all at P < .05). At E2, implant location, diameter, length, and experimental group significantly affected implant stability (all at P < .05). At E3, bone quality, implant diameter, length, and experimental group significantly affected implant stability (all at P < .01). Stability for the RB12 group was significantly higher than all other corresponding values; further, the values did not change significantly over time. For the HB and RB6 groups, stability was significantly higher at E2 than at E1 (P < .001) and was no different between E2 and E3. Implant location, length, and experimental group were associated with these differences (all at P < .05). Compared with HB and RB6, higher implant stability may be achieved in regenerated bone 12 months post-extraction (RB12). This stability was achieved at E1 and maintained for at least 8 months. Variables such as implant length, diameter, and bone quality affected the stability differently over time. Implant stability varied in different anatomic regions and with regard to different healing processes in the bone. PMID:25106008

Deli, Giorgio; Petrone, Vincenzo; De Risi, Valeria; Tadic, Drazen; Zafiropoulos, Gregory-George

2014-08-01

366

Scales and Tooth Whorls of Ancient Fishes Challenge Distinction between External and Oral 'Teeth'  

PubMed Central

The debate about the origin of the vertebrate dentition has been given fresh fuel by new fossil discoveries and developmental studies of extant animals. Odontodes (teeth or tooth-like structures) can be found in two distinct regions, the ‘internal’ oropharyngeal cavity and the ‘external’ skin. A recent hypothesis argues that regularly patterned odontodes is a specific oropharyngeal feature, whereas odontodes in the external skeleton lack this organization. However, this argument relies on the skeletal system of modern chondrichthyans (sharks and their relatives), which differ from other gnathostome (jawed vertebrate) groups in not having dermal bones associated with the odontodes. Their external skeleton is also composed of monoodontode 'placoid scales', whereas the scales of most early fossil gnathostomes are polyodontode, i.e. constructed from several odontodes on a shared bony base. Propagation phase contrast X-ray Synchrotron microtomography (PPC-SRµCT) is used to study the polyodontode scales of the early bony fish Andreolepis hedei. The odontodes constructing a single scale are reconstructed in 3D, and a linear and regular growth mechanism similar to that in a gnathostome dentition is confirmed, together with a second, gap-filling growth mechanism. Acanthodian tooth whorls are described, which show that ossification of the whorl base preceded and probably patterned the development of the dental lamina, in contrast to the condition in sharks where the dental lamina develops early and patterns the dentition.The new findings reveal, for the first time, how polyodontode scales grow in 3D in an extinct bony fish. They show that dentition-like odontode patterning occurs on scales and that the primary patterning unit of a tooth whorl may be the bony base rather than the odontodes it carries. These results contradict the hypothesis that oropharyngeal and external odontode skeletons are fundamentally separate and suggest that the importance of dermal bone interactions to odontode patterning has been underestimated. PMID:23951264

Qu, Qingming; Sanchez, Sophie; Blom, Henning; Tafforeau, Paul; Ahlberg, Per Erik

2013-01-01

367

A Journey from Dental Pulp Stem Cells to a Bio-tooth  

Microsoft Academic Search

The ultimate goal of tooth regeneration is to replace the lost teeth. Stem cell-based tooth engineering is deemed as a promising\\u000a approach to the making of a biological tooth (bio-tooth). Dental pulp stem cells (DPSCs) represent a kind of adult cell colony\\u000a which has the potent capacity of self-renewing and multilineage differentiation. The exact origin of DPSCs has not been

Ming Yan; Yan Yu; Guangdong Zhang; Chunbo Tang; Jinhua Yu

2011-01-01

368

Occlusal concepts application in resolving implant prosthetic failure: case report.  

PubMed

The prosthetic management of a poor implant treatment is presented in this case report. The recommended occlusion concepts for implant-supported prostheses were applied for the resolution of the case. The rehabilitation of the posterior segments provided a mutually protected occlusion with adequate distribution of the axial and lateral bite forces with stable posterior occlusion. The clinical exam indicated the need for modification in the vertical dimension of occlusion. Sufficient interocclusal rest space was present to test the alteration in the vertical dimension. The aim was to achieve an occlusion scheme that followed four specific criteria: (1) centric contacts and centric relation of the jaw-to-jaw position; (2) anterior guidance only; (3) shallow anterior angle of tooth contact; and (4) vertical dimension of occlusion with acceptable tooth form and guidance. The success of an oral rehabilitation relies in following the aforementioned criteria, appropriate interaction between the dental laboratory technician and the clinician, careful elaboration of the provisional rehabilitation with all the desired details to be reproduced in the final prosthetic restoration and sufficient follow-up time of the provisional prostheses before placing the final restoration. PMID:22251257

Jamcoski, Vanessa Helena; Faot, Fernanda; de Mattias Sartori, Ivete Aparecida; Vieira, Rogéria Acedo; Tiossi, Rodrigo

2014-04-01

369

Simple, Effective—and Inexpensive— Strategies to Reduce Tooth Decay in Children  

Microsoft Academic Search

Access to primary preventive dental care will likely decrease in a poor economy, challenging all health care providers to identify inexpensive ways to help families prevent tooth decay. The incidence of tooth decay in very young children is increasing. Tooth decay can result in death in children if the subsequent infection is untreated. However, easy, inexpensive, and effective strategies exist

Jennifer Holtzman

2009-01-01

370

Tooth development in a scincid lizard, Chalcides viridanus (Squamata), with particular attention to enamel formation  

Microsoft Academic Search

Comparative analysis of tooth development in the main vertebrate lineages is needed to determine the various evolutionary routes leading to current dentition in living vertebrates. We have used light, scanning and transmission electron microscopy to study tooth morphology and the main stages of tooth development in the scincid lizard, Chalcides viridanus, viz., from late embryos to 6-year-old specimens of a

Sidney Delgado; Tiphaine Davit-Béal; Françoise Allizard; Jean-Yves Sire

2005-01-01

371

A review of heat transfer in human tooth—Experimental characterization and mathematical modeling  

Microsoft Academic Search

With rapid advances in modern dentistry, high-energy output instruments (e.g., dental lasers and light polymerizing units) are increasingly employed in dental surgery for applications such as laser assisted tooth ablation, bleaching, hypersensitivity treatment and polymerization of dental restorative materials. Extreme high temperature occurs within the tooth during these treatments, which may induce tooth thermal pain (TTP) sensation. Despite the wide

Min Lin; Feng Xu; Tian Jian Lu; Bo Feng Bai

2010-01-01

372

Properties of tooth enamel in great apes James J.-W. Lee a,*, Dylan Morris a  

E-print Network

Properties of tooth enamel in great apes James J.-W. Lee a,*, Dylan Morris a , Paul J. Constantino tooth enamel. Nanoindentation tech- niques are used to map profiles of elastic modulus and hardness across sections from the enamel­dentin junction to the outer tooth surface. The measured data profiles

Smith, Tanya M.

373

Decomposition of the laboratory gamma irradiation component of angular ESR spectra of fossil tooth enamel fragments  

E-print Network

of fossil tooth enamel fragments using an automated simulated annealing (SA) procedure shows that the mix and transfer processes that leads to the observed mix of COÃ? 2 radicals in fossil tooth enamel is essential follows our earlier studies on the spectrum decomposition of fossil tooth enamel fragments (Joannes

Bodin, Thomas

374

Isotopic analysis of tooth enamel carbonate from modern North American feral horses  

E-print Network

Isotopic analysis of tooth enamel carbonate from modern North American feral horses: implications and oxygen isotope values (N13 C and N18 O) of tooth enamel carbonate and the N13 C values of fecal samples isotope analyses of fecal material and tooth enamel suggest that horses consumed primarily grass, but some

Amundson, Ronald

375

Continuous tooth generation in mouse is induced by activated epithelial Wnt/ -catenin signaling  

E-print Network

as an upstream activator of enamel knot formation. These results may implicate Wnt signaling in tooth re- newalContinuous tooth generation in mouse is induced by activated epithelial Wnt/ -catenin signaling and feathers, whose continuous replacement has been linked to Wnt signaling. Here we show that mouse tooth buds

Jernvall, Jukka

376

Dependencies of the radiation sensitivity of human tooth enamel in EPR dosimetry  

Microsoft Academic Search

The EPR dose response of tooth enamel was determined for human molars collected in Egypt. The influence of age, gender and residence of the tooth donors as well as tooth position and sample preparation on EPR sensitivity and its variability over the enamel samples was investigated. The EPR sensitivity and its variability were found to depend only on the sample

A. Wieser; N. El-Faramawy; R. Meckbach

2001-01-01

377

The reconstruction of mammal individual history: refining high-resolution isotope record in bovine tooth dentine  

E-print Network

) of tooth enamel for several reasons. First, because of its larger, more tightly packed and highly organized tooth dentine Antoine Zazzo a,b,*, Marie Balasse c , William P. Patterson a a Department of Geological performed on tooth dentine from five steers (Bos taurus) initially fed C3 and subsequently C4-dominant food

Patterson, William P.

378

UNCORRECTEDPROOF 2 Mitochondrial fusion and function in CharcotMarieTooth type  

E-print Network

UNCORRECTEDPROOF 1 2 Mitochondrial fusion and function in Charcot­Marie­Tooth type 3 2A patient January 2008; accepted 11 January 2008 16 Abstract 17 Charcot­Marie­Tooth Type 2A is a dominantly, 2007, Chen and Chan, 2006). 38Charcot­Marie­Tooth disease Type 2A (CMT2A) is an 39autosomal dominant

Shaw, Janet M.

379

Comparison of intermaxillary tooth size discrepancies among different malocclusion groups  

Microsoft Academic Search

The purpose of this study was to determine whether there is a prevalent tendency for intermaxillary tooth size discrepancies among different malocclusion groups. This study consisted of 60 subjects who served as the normal occlusion group and 300 patients divided into 5 malocclusion groups (ie, Class I with bimaxillary protrusion, Class II Division 1, Class II Division 2, Class III,

Qiong Nie; Jiuxiang Lin

1999-01-01

380

Neuroblastoma and tooth abnormalities: a common history? ABADIE Caroline1  

E-print Network

the hypothesis of a common underlying genetic defect because of common cell origin. Dental data were obtained via) treated with chemotherapy and autologous stem cell transplantation but at age 10. inserm-00825411,version1, arises from embryonic neural crest cells. Tooth development begins before birth and continues for 12

Paris-Sud XI, Université de

381

Reducing Baby Bottle Tooth Decay. A SERVE Research Brief.  

ERIC Educational Resources Information Center

This pamphlet discusses strategies for reducing baby bottle tooth decay (BBTD) among Native American children. BBTD in infants and toddlers is a painful disease characterized by extensive decay of the upper front and side teeth. It is caused by prolonged exposure of teeth to carbohydrates, such as those contained in infant formula, milk, and fruit…

Southeastern Regional Vision for Education (SERVE), Tallahassee, FL.

382

Identification of tooth decay using terahertz imaging and spectroscopy  

Microsoft Academic Search

Terahertz (THz) frequency spectroscopic imaging studies of teeth are reported. The aim is to establish the characteristic properties of the enamel and dentine at these high frequencies. Changes to the THz characteristics as a result of various types of tooth decay are reported showing the potential of this technique for dental diagnosis.

N. N. Zinov'ev; A. F. Fitzgerald; S. M. Strafford; D. J. Wood; F. A. Carmichael; R. E. Miles; M. A. Smith; J. M. Chamberlain

2002-01-01

383

Tooth Decay Diagnosis using Back Propagation Neural Network  

Microsoft Academic Search

Artificial neural network (ANN), with its high performances in handling complex problems, has been widely used in medical image processing for clinical diagnostic application. In this paper, an ANN tooth decay diagnostic strategy was proposed and carefully experimented. A back propagation (BP) neural network was formed to analyze the X-ray image of patient's teeth. With inter-pixel autocorrelation coefficients as its

Yang Yu; Yun Li; Yu-Jing Li; Jian-Ming Wang; Dong-Hui Lin; We-Ping Ye

2006-01-01

384

Changes in maternal attitudes toward baby bottle tooth decay  

Microsoft Academic Search

Several studies have shown that a significant number of parents whose children have baby bottle tooth decay (BBTD) admit prior knowledge regarding the harmful ef- fects of putting their children to bed with a bottle. The Elaboration Likelihood Model of Persuasion (ELM) offers a theoretical framework for better understanding why knowledge and attitude are often not predictive of behav- ior.

Michael J. Kanellis; Henrietta L. Logan; Jane Jakobsen

1997-01-01

385

Intra-oral PTH administration promotes tooth extraction socket healing.  

PubMed

Intermittent parathyroid hormone (PTH) administration increases systemic and craniofacial bone mass. However, the effect of PTH therapy on healing of tooth extraction sites is unknown. The aims of this study were to determine the effect of PTH therapy on tooth extraction socket healing and to examine whether PTH intra-oral injection promotes healing. The mandibular first molars were extracted in rats, and subcutaneous PTH was administered intermittently for 7, 14, and 28 days. In a second study, maxillary second molars were extracted, and PTH was administered by either subcutaneous or intra-oral injection to determine the efficacy of intra-oral PTH administration. Healing was assessed by micro-computed tomography and histomorphometric analyses. PTH therapy accelerated the entire healing process and promoted both hard- and soft-tissue healing by increasing bone fill and connective tissue maturation. PTH therapy by intra-oral injection was as effective as subcutaneous injection in promoting tooth extraction socket healing. The findings suggest that PTH therapy promotes tooth extraction socket healing and that intra-oral injections can be used to administer PTH. PMID:23611925

Kuroshima, S; Kovacic, B L; Kozloff, K M; McCauley, L K; Yamashita, J

2013-06-01

386

Biomimetic hybrid scaffolds for engineering human tooth-ligament interfaces  

Microsoft Academic Search

A major clinical challenge in the reconstruction of large oral and craniofacial defects is the neogenesis of osseous and ligamentous interfacial structures. Currently, oral regenerative medicine strategies are unpredictable for repair of tooth-supporting tissues destroyed as a consequence of trauma, chronic infection or surgical resection. Here, we demonstrate multi-scale computational design and fabrication of composite hybrid polymeric scaffolds for targeted

Chan Ho Park; Hector F. Rios; Qiming Jin; Megan E. Bland; Colleen L. Flanagan; Scott J. Hollister; William V. Giannobile

2010-01-01

387

Comparison of intermaxillary tooth size discrepancies among different malocclusion groups.  

PubMed

The purpose of this study was to determine whether there is a prevalent tendency for intermaxillary tooth size discrepancies among different malocclusion groups. This study consisted of 60 subjects who served as the normal occlusion group and 300 patients divided into 5 malocclusion groups (ie, Class I with bimaxillary protrusion, Class II Division 1, Class II Division 2, Class III, and Class III surgery). Tooth size measurements were performed on the models of normal occlusion and pretreatment models of patients by the Three Dimension Measuring Machine. Moreover, tooth size ratios, analyzed as described by Bolton and the Student t test showed no sexual dimorphism for these ratios in each of 6 groups, so the sexes were combined for each group. Then these ratios were compared among different malocclusion groups. The results showed no significant difference between subcategories of malocclusion, so these groups were combined. There were now 120 cases in each of 3 categories: Class I, Class II, and Class III. A significant difference was found for all the ratios between the groups, the ratios showing that Class III > Class I > Class II. It demonstrated that intermaxillary tooth size discrepancy may be one of the important factors in the cause of malocclusions, especially in Class II and Class III malocclusions. Thus this study proved the fact that Bolton analysis should be taken into consideration during orthodontic diagnosis and therapy. PMID:10547514

Nie, Q; Lin, J

1999-11-01

388

Periodontal Disease, Tooth Loss, and Incidence of Ischemic Stroke  

Microsoft Academic Search

Background and Purpose—Periodontal and other infections have been suggested as potential risk factors for stroke. This study evaluates periodontal disease and tooth loss as risk factors for ischemic stroke. Methods—The study population consisted of 41 380 men who were free of cardiovascular disease and diabetes at baseline. Periodontal disease history was assessed by mailed validated questionnaires. During 12 years of

Kaumudi J. Joshipura; Hsin-Chia Hung; Eric B. Rimm; Walter C. Willett; Alberto Ascherio

389

Making a tooth: growth factors, transcription factors, and stem cells  

Microsoft Academic Search

Mammalian tooth development is largely dependent on sequential and reciprocal epithelial-mesenchymal interactions. These processes involve a series of inductive and permissive interactions that result in the determination, differentiation, and organization of odontogenic tissues. Multiple signaling molecules, including BMPs, FGFs, Shh, and Wnt proteins, have been implicated in mediating these tissue interactions. Transcription factors participate in epithelial-mesenchymal interactions via linking the

Yan Ding ZHANG; Zhi CHEN; Yi Qiang SONG; Chao LIU; Yi Ping CHEN

2005-01-01

390

Fetal age estimation using MSCT scans of deciduous tooth germs.  

PubMed

Evaluation of fetal age is an essential element in many fields such as anthropology, odontology, paleopathology, and forensic sciences. This study examines the correlation between fetal age, femoral diaphyseal length (considered as the gold standard), and deciduous tooth germs of fetuses aged 22 to 40 weeks amenorrhea (WA) based on computed tomography (MSCT) reconstructions. Qualitative and quantitative studies of femoral and deciduous tooth germ lengths were performed on 81 fetuses (39 females and 42 males). R software was used for statistical analyses. Intra-observer and inter-observer variabilities and the interclass correlation coefficient (ICC) were calculated. Correlation coefficients (R (2)) and linear regression equations were calculated. Intra- and inter-observer variabilities were very satisfactory (intra-observer ICC???0.96, inter-observer ICC???0.95). Femoral length was significantly correlated with age (R (2)?=?0.9). The correlation coefficient between age and height, width, and dental volume was R (2)???0.73. Tooth germs were good indicators of fetal age. Our method appears to be reliable and reproducible, and the results of this study agreed with those of the literature. The dental formula provided a precise estimation of fetal age between 25 and 32 WA. Tooth germs were reliable indicators of fetal age, and multislice computed tomography was shown to be an innovative and reliable technology for this purpose. PMID:23828625

Minier, Marie; Maret, Delphine; Dedouit, Fabrice; Vergnault, Marion; Mokrane, Fathima-Zohra; Rousseau, Hervé; Adalian, Pascal; Telmon, Norbert; Rougé, Daniel

2014-01-01

391

Are You Feeding Your Kids Tooth-Friendly Foods?  

MedlinePLUS

... what's a parent to do? Experts agree that a child needs foods from all the major food groups in order to grow properly and stay healthy. When ... the teeth. This can contribute to tooth decay. Choosing milk or water will help ... only nutritious foods in the house. Offer lots of fruits and vegetables. ...

392

Charcot-Marie-Tooth Disease as a Disabling Disorder  

PubMed Central

The author looks at Charcot-Marie-Tooth disease and the disabling effects that it can have on the patient. A course of action is outlined to help the patient cope more fully with this fairly common but little understood disorder. ImagesFigure 1Figure 2Figure 3 PMID:21248895

Crabtree, Linda

1989-01-01

393

Paramagnetic resonance in tooth enamel created by ultraviolet light  

Microsoft Academic Search

Paramagnetic centres are present in human tooth enamel after irradiation with ultraviolet light. Their thermal stability and electron spin resonance spectrum coincide with those of the ion radicals created with ?-rays are used in geological or archaeological dating and accident dosimetry. The long wavelength tail of their creation spectrum intersects with the short wavelength tail of the solar spectrum reaching

Georg Liidja; Jaan Past; Jüri Puskar; Endel Lippmaa

1996-01-01

394

Current issues on EPR dose reconstruction in tooth enamel  

Microsoft Academic Search

This paper focuses on the opportunities to gain risk assessment information from populations exposed to ionizing radiation. Details are presented on the scale of the nuclear events in several areas within the former Soviet Union. An overview of the issues associated with dose reconstruction by electron paramagnetic resonance (EPR) is given. Principles and outline of the EPR tooth enamel dose

Alexander A. Romanyukha; Marc F. Desrosiers; Dieter F. Regulla

2000-01-01

395

Tooth enamel EPR dosimetry: sources of errors and their correction  

Microsoft Academic Search

Some of the most important sources of systematic errors in dose determination using tooth enamel EPR spectroscopy and ways of reducing those errors are discussed. Enamel from the outside of the front teeth should not be used for dose determination because of induction of paramagnetic centers by solar light. The accuracy of the method in the low dose range is

A. I. Ivannikov; V. G. Skvortsov; V. F. Stepanenko; A. F. Tsyb; L. G. Khamidova; D. D. Tikunov

2000-01-01

396

Fabrication and anti-microbial evaluation of drug loaded polylactide space filler intended for ridge preservation following tooth extraction  

PubMed Central

Background: The preservation or reduction of alveolar ridge resorption following tooth extraction is important in patients especially for those intended for implants at a later stage. One way to achieve this is by using membranes, graft materials, and biodegradable space fillers to prevent alveolar bone resorption and promote regeneration. A major attraction for using biodegradable and biocompatible polymers as space fillers for ridge preservation is their safety profile in comparison to xenograft materials like lyophilized bone and collagen. Materials and Methods: Biocompatible polylactide space fillers were fabricated by fusing porous polylactide particles. The sponges were loaded with drugs by placing them in the respective solutions. Pseudomonas aeruginosa was isolated from a chronic periodontitis patient and in vitro anti-microbial evaluation was done with the drug loaded sponges. Results: Chlorhexidine loaded space filler showed significant anti microbial effect against multiple drug resistant Pseudomonas aeruginosa isolated from a patient with chronic periodontitis. Conclusion: The results of this study indicate that biodegradable drug releasing polylactide space fillers has the potential to be used for ridge preservation following tooth extraction. Release of drugs in the socket may prove useful in preventing development of alveolar osteitis post extraction which can interfere with normal healing of the socket. Synthetic biodegradable polymers also exhibit a controlled degradation rate to achieve complete resorption within the intended time. PMID:22028514

Thomas, Nebu George; Sanil, George P.; Rajmohan, Gopimohan; Prabhakaran, Jayachandran V.; Panda, Amulya K.

2011-01-01

397

Dental patterning in the earliest sharks: Implications for tooth evolution.  

PubMed

Doliodus problematicus is the oldest known fossil shark-like fish with an almost intact dentition (Emsian, Lower Devonian, c. 397Ma). We provide a detailed description of the teeth and dentition in D. problematicus, based on tomographic analysis of NBMG 10127 (New Brunswick Museum, Canada). Comparisons with modern shark dentitions suggest that Doliodus was a ram-feeding predator with a dentition adapted to seizing and disabling prey. Doliodus provides several clues about the early evolution of the "shark-like" dentition in chondrichthyans and also raises new questions about the evolution of oral teeth in jawed vertebrates. As in modern sharks, teeth in Doliodus were replaced in a linguo-labial sequence within tooth families at fixed positions along the jaws (12-14 tooth families per jaw quadrant in NBMG 10127). Doliodus teeth were replaced much more slowly than in modern sharks. Nevertheless, its tooth formation was apparently as highly organized as in modern elasmobranchs, in which future tooth positions are indicated by synchronized expression of shh at fixed loci within the dental epithelium. Comparable dental arrays are absent in osteichthyans, placoderms, and many "acanthodians"; a "shark-like" dentition, therefore, may be a synapomorphy of chondrichthyans and gnathostomes such as Ptomacanthus. The upper anterior teeth in Doliodus were not attached to the palatoquadrates, but were instead supported by the ethmoid region of the prechordal basicranium, as in some other Paleozoic taxa (e.g., Triodus, Ptomacanthus). This suggests that the chondrichthyan dental lamina was originally associated with prechordal basicranial cartilage as well as jaw cartilage, and that the modern elasmobranch condition (in which the oral dentition is confined to the jaws) is phylogenetically advanced. Thus, oral tooth development in modern elasmobranchs does not provide a complete developmental model for chondrichthyans or gnathostomes. PMID:24347366

Maisey, John G; Turner, Susan; Naylor, Gavin J P; Miller, Randall F

2014-05-01

398

Prevalence and patterns of tooth agenesis among Malay children.  

PubMed

Tooth agenesis in Malay children, hitherto unreported, was assessed retrospectively from orthopantomograms of 834 healthy children aged 12-16 years who attended the Dental Clinic of Universiti Sains Malaysia. All teeth, including third molars, were assessed for agenesis. On an average, 2.3 teeth were missing per child. Missing third molars were found in 25.7% of children with one or two third molars found to be missing in 18.3% of children. Three point two percent of children had missing teeth other than third molars. After third molars, the upper lateral incisors were found to be the most common missing tooth (1.7%), followed by upper and lower second premolars (1.5%). Eight missing upper canines were also seen (1%). Bilateral agenesis was more common than unilateral agenesis. There were no significant differences between males and females. There was a significant difference between missing teeth between the maxilla and the mandible and right and left side, with more missing teeth in the maxilla and on the right side. The odds of any 3rd molar missing were increased 3.3 times when there was any other missing tooth. In conclusion, the prevalence of tooth agenesis among the studied population was within the normal range, but less than some Asian countries. Unlike other Asian countries, the upper lateral incisor was the most common missing tooth. The prevalence of maxillary canine agenesis was higher than most previous reports. Missing teeth were associated with missing third molars, which is likely due to a genetic abnormality. PMID:24968691

Mani, Shani Ann; Mohsin, Wan Salmah Yang; John, Jacob

2014-03-01

399

Sea urchin tooth mineralization: Calcite present early in the aboral plumula  

PubMed Central

In both vertebrate bone, containing carbonated hydroxyapatite as the mineral phase, and in invertebrate hard tissue comprised of calcium carbonate, a popular view is that the mineral phase develops from a long-lived amorphous precursor which later transforms into crystal form. Important questions linked to this popular view are: When and where is the crystallized material formed, and is amorphous solid added subsequently to the crystalline substrate? Sea urchin teeth, in which the earliest mineral forms within isolated compartments, in a time and position dependent manner, allow direct investigation of the timing of crystallization of the calcite primary plates. Living teeth of the sea urchin Lytechinus variegatus, in their native coelomic fluid, were examined by high-energy synchrotron x-ray diffraction. The diffraction data show that calcite is present in the most aboral portions of the plumula, representing the very earliest stages of mineralization, and that this calcite has the same crystal orientation as in the more mature adoral portions of the same tooth. Raman spectroscopy of the aboral plumula confirms the initial primary plate mineral material is calcite and does not detect amorphous calcium carbonate; in the more mature adoral incisal flange, it does detect a broader calcite peak, consistent with two or more magnesium compositions. We hypothesize that some portion of each syncytial membrane in the plumula provides the information for nucleation of identically oriented calcite crystals that subsequently develop to form the complex geometry of the single crystal sea urchin tooth. PMID:22940703

Stock, Stuart R.; Veis, Arthur; Xiao, Xianghui; Almer, Jonathan D.; Dorvee, Jason R.

2012-01-01

400

ERK is involved in tooth-pressure-induced Fos expression in Vc neurons.  

PubMed

Discomfort and pain encountered during orthodontic treatment are major problems for patients, but the details of the underlying neural processes and molecular mechanisms are not well-understood. Here we show that noxious tooth mechanical pressure induced by orthodontic elastics resulted in a rapid and transient activation of extracellular signal-regulated protein kinase (ERK) in the trigeminal spinal subnucleus interpolaris and caudalis transition zone (Vi/Vc), trigeminal spinal subnucleus caudalis (Vc), and upper cervical spinal cord (Vc/C2). The phosphorylated ERK (pERK) was observed in neurons but not in astroglia and microglia. Single-plane scanning analysis indicated that the pERK was localized to the nucleus of Vc neurons. In addition, the tooth mechanical pressure led to Fos expression in the pERK-positive Vc neurons that would be suppressed by intrathecal administration of an MEK1/2 inhibitor (PD98059). Taken together, these findings suggest that activation of the ERK signaling cascade following noxious mechanical pressure on the teeth regulates Fos expression in Vc neurons and may thereby contribute to pain associated with orthodontic treatment. PMID:23018815

Hasegawa, M; Kondo, M; Suzuki, I; Shimizu, N; Sessle, B J; Iwata, K

2012-12-01

401

Giant-toothed White Sharks and Wide-toothed Mako (Lamnidae) from the Venezuela Neogene: Their Role in the Caribbean, Shallow-water Fish Assemblage  

Microsoft Academic Search

The role of Neogene giant-toothed lamnid sharks in the Caribbean neritic fish assemblage is discussed based on predator-prey relationships in three different tropical paleoenvironments from the Lower Miocene to Lower Pliocene. New records of extinct giant-toothed white sharks Carcharodon megalodon (Agassiz), Carcharodon subarticulatus (Agassiz), and wide-toothed mako Isurus xiphodon (Agassiz) from coastal shallow waters, coastal upwelling, swampy, coastal lagoon, and

ORANGEL AGUILERA; DIONE RODRIGUES DE AGUILERA

402

Use of intraoral welding to stabilize dental implants in augmented sites for immediate provisionalization: a case report.  

PubMed

Immediate implant rehabilitation of edentulous arches may be somewhat problematic because of anatomic situations involving insufficient bone thickness or height and tooth position. The aim of this report was to present a retrospective case series of dental implants placed into augmented sites (split crest or sinus augmentation) that were stabilized with an intraorally welded framework at the time of immediate provisionalization. An intraoral welding unit was used to join and stabilize implants as an orthopedic splint to break down forces applied on provisional restorations during healing and osseointegration. This approach allows for the immediate provisionalization of implants in bone-defective areas where multiple implant systems have been enacted. Forty-eight implants in 16 patients were inserted, welded together to a titanium framework, and immediately provisionalized during the same surgery in which split-crest or sinus augmentation procedures were performed. After removing the welded frameworks, 1 of 48 implants failed; the failed implant was associated with a sinus augmentation procedure. Intraoral welding stabilization may be a predictable procedure to allow immediate loading in augmented areas during healing time and to stabilize implants against nonaxial forces, thereby reducing the number of surgical and prosthetic sessions and making patients comfortable and accustomed to immediate fixed provisional and definitive restorations. PMID:20932150

Avvanzo, Pierluigi; Fabrocini, Lelio A; Ciavarella, Domenico; Avvanzo, Andrea; Lo Muzio, Lorenzo; De Maio, Raffaele A

2012-02-01

403

Platform switching and abutment emergence profile modification on peri-implant soft tissue.  

PubMed

Although the peri-implant hard tissue advantages of platform switching abutments have been well documented by many authors, the peri-implant soft tissue advantages of platform switching abutments has had limited mention. This article illustrates how the amount of peri-implant soft tissue volume is influenced by the dimensional extent of platform switching and the degree that an abutment's sulcular emergence profile has been modified. This article also introduces the term "abutment sulcular emergence profile enhancement" (ASEPE) to describe the combined effect of platform switching and abutment emergence profile modification. Three unrecognized clinical advantages of ASEPE are described by different clinical cases. First, elimination of excessive abutment impingement on gingival tissue adjacent to implants is achieved. Second, allowance for sufficient interproximal space between implant and adjacent tooth/implant for the entry of interproximal toothbrush is made possible. Third, excessive soft tissue blanching during abutment seating at prosthesis delivery is eliminated. Together, the combined application of platform switching and abutment emergence profile modification represents the opening of a new realm for managing soft tissue around implants to resolve dimensional problems. PMID:25269220

Dornbush, Jeffrey R; Reiser, Gary M; Ho, Daniel K

2014-01-01

404

Assessment of Tooth Preparation via Er:YAG Laser and Bur on Microleakage of Dentin Adhesives  

PubMed Central

Objective Microleakage can be responsible for tooth hypersensitivity, secondary caries, and the possibility of pathological pulp alterations in restored teeth. Recently, alternative methods for tooth preparation such as laser irradiation have been studied; but there are limited studies on primary teeth. The aim of this in vitro study was to compare the degree of microleakage of composite restorations prepared by Er:YAG laser and conventional bur preparation with two adhesive systems in primary teeth. Materials and Methods: Eighty primary canine teeth were randomly divided into 4 groups. Class V cavities were prepared by Er:YAG laser or diamond bur on buccal surface. The groups were as follows: group1: High speed drill + self-etching adhesive Adper Prompt-L-Pop, group 2: Er:YAG laser + etch & rinse adhesive Adper Single Bond, group 3: High speed drill + Adper Single Bond, group 4: Er:YAG laser + Adper Prompt-L-Pop. Cavities were restored with Filtek Z250 composite resin. Then all of the specimens were polished, thermocycled, immersed in 2% methylene blue solution and sectioned longitudinally. Degree of microleakage was evaluated by two evaluators who assigned the micrleakage score (0 to 3). The original data were analyzed by the Kruskal-Wallis and Dunn’s tests. Results: There were significant differences between bur-prepared cavities in the Adper Single Bond and other groups. There were no statistically significant differences between other groups. Conclusion: Laser-prepared cavities showed higher microleakage scores than cavities prepared with diamond bur with etch and rinse adhesive system. No significant difference was revealed between the laser and bur-prepared cavities using self-etch primers. PMID:24910693

Bahrololoomi, Zahra; Heydari, Elham

2014-01-01

405

Peri-implant mucositis and peri-implantitis: bacterial infection.  

PubMed

Osseointegrated dental implants have a ong-term success rate of over 90%, but may be threatened by peri-implant mucostis and peri-implantitis, bacteria biofilm-induced inflammatory conditions. While peri-implant mucositis is a reversible inflammatory condition confined to the peri-implant soft-tissue unit, peri-implantitis is characterised by progressive inflammatory destruction of the crest of the alveolar bone supporting the implant, by increased peri-implant probing depths, and by bleeding and/or suppuration on probing. Effective treatment of peri-implant mucositis will prevent the development of peri-implantitis. Plaque accumulation on the implant/abutment surface juxtaposed to the junctional epithelium and to the connective tissue zone of the peri-implant soft-tissue unit induces the development of peri-implant mucositis which can subsequently progress to peri-implantitis. The aim of this paper is to review some aspects of bacterial infection of the tissue supporting dental implants, and to explore how to maintain the healthy peri-implant soft-tissue unit. PMID:23189895

Khammissa, R A G; Feller, L; Meyerov, R; Lemmer, J

2012-03-01

406

Dietary and environmental reconstruction with stable isotope analyses of herbivore tooth enamel from the Miocene locality of Fort Ternan, Kenya  

Microsoft Academic Search

Tooth enamel of nine Middle Miocene mammalian herbivores from Fort Ternan, Kenya, was analyzed for ?13C and ?18O. The ?18O values of the tooth enamel compared with pedogenic and diagenetic carbonate confirm the use of stable isotope analysis of fossil tooth enamel as a paleoenvironmental indicator. Furthermore, the ?18O of tooth enamel indicates differences in water sources between some of

Thure E. Cerling; John M. Harris; Stanley H. Ambrose; Meave G. Leakey; Nikos Solounias

1997-01-01

407

Clinical Features: Charcot Marie Tooth Disease is a group of inherited neuropathies characterized by chronic motor and sensory  

E-print Network

1/13 Clinical Features: Charcot Marie Tooth Disease is a group of inherited neuropathies-499-9264 Email: info@charcot-marie-tooth.org http://www.charcot-marie-tooth.org/ The Muscular Dystrophy Association 3300 E. Sunrise Drive Tucson, AZ 85718 800-572-1717 http://www.mda.org/ European Charcot-Marie-Tooth

Ober, Carole

408

Clinical Features: Charcot Marie Tooth Disease is a group of inherited neuropathies characterized by chronic motor and sensory  

E-print Network

10/08 Clinical Features: Charcot Marie Tooth Disease is a group of inherited neuropathies-499-9264 Email: info@charcot-marie-tooth.org http://www.charcot-marie-tooth.org/ The Muscular Dystrophy Association 3300 E. Sunrise Drive Tucson, AZ 85718 800-572-1717 http://www.mda.org/ European Charcot-Marie-Tooth

Gilad, Yoav

409

Clinical Features: Charcot Marie Tooth Disease is a group of inherited neuropathies characterized by chronic motor and sensory  

E-print Network

6/11 Clinical Features: Charcot Marie Tooth Disease is a group of inherited neuropathies-499-9264 Email: info@charcot-marie-tooth.org http://www.charcot-marie-tooth.org/ The Muscular Dystrophy Association 3300 E. Sunrise Drive Tucson, AZ 85718 800-572-1717 http://www.mda.org/ European Charcot-Marie-Tooth

Ober, Carole

410

[Implantable ventricular assist device].  

PubMed

Implantable ventricular assist device( VAD) is the only evidence-based option to treat stage D heart failure patients with significant symptoms at rest in spite of maximum medical therapy, other than heart transplant. Implantable VADs available in Japan include Evaheart, DuraHeart both from Japan, Jarvik 2000 and HeartMate II both from United States. In Japanese settings, implantable VAD is indicated and insured only for patients who are supposed to have an indication for receiving heart transplant, which means "bridge to transplantation" use. And in Japan, implantable VAD can be implanted for patients less than 65 years old if it needs to be insured. In the University of Tokyo Hospital, the mid-term outcomes of 41 implantable VAD patients were acceptable with 2 hospital deaths, 2 remote deaths and oneyear survival rate at 88%.Considering the present Japanese situation with extreme shortage of organ donation, the extended application of implantable VADs as "Destination Therapy" is awaited, but quality of life of care-givers as well as patients themselves and sustainable follow-up system provided by healthcare professionals need to be warranted. PMID:25138935

Nawata, Kan; Kinoshita, Osamu; Kimura, Mitsutoshi; Ono, Minoru

2014-07-01

411

Thin film multiferroic nanocomposites by ion implantation.  

PubMed

Thin film multiferroic nanocomposites might enable a range of potentially disruptive integrated magnetoelectric devices for information storage, spintronics, microwave telecommunications, and magnetic sensing. With this aim, we have investigated ion implantation of magnetic species into ferroelectric single crystal targets as a radically novel approach to prepare film nanoparticulate magnetic-metal ferroelectric-oxide composites. These materials are an alternative to multiferroic oxide epitaxial columnar nanostructures that are under intensive research, but whose magnetoelectric response is far from expectations. Here, we unambiguously demonstrate the preparation of such a thin film multiferroic nanocomposite of Co and BaTiO3 by ion implantation of a high dose of the magnetic species, followed by rapid thermal processing under tailored conditions. Results thus constitute a proof of concept for the feasibility of obtaining the materials by this alternative approach. Ion implantation is a standard technique for the microelectronic industry in combination with well-established patterning procedures. PMID:24417708

Algueró, Miguel; Ricote, Jesús; Torres, María; Amorín, Harvey; Alberca, Aurora; Iglesias-Freire, Oscar; Nemes, Norbert; Holgado, Susana; Cervera, Manuel; Piqueras, Juan; Asenjo, Agustina; García-Hernández, Mar

2014-02-12

412

Transcatheter aortic valve implantation  

PubMed Central

Transcatheter aortic valve implantation was developed to offer a therapeutic solution to patients with severe symptomatic aortic stenosis who are not candidates for conventional aortic valve replacement. The improvement in transcatheter aortic valve implantation outcomes is still of concern in the areas of stroke, vascular injury, heart block, paravalvular regurgitation and valve durability. Concomitantly, the progress, both technical and in terms of material advances of transcatheter valve systems, as well as in patient selection, renders transcatheter aortic valve implantation an increasingly viable treatment for more and more patients with structural heart disease. PMID:25374670

Oliemy, Ahmed

2014-01-01

413

Excimer laser interaction with dentin of the human tooth  

NASA Technical Reports Server (NTRS)

The use an excimer laser produced many unusual conical structures within the dentin of the inner part of the human tooth. By varying the frequency of the laser one can disperse the energy and cause more bleeding in laser surgery, but not destroy the cells associated with the incision. Therefore, the healing process will virtually be without scarring. Whereas, using the infrared laser the blood loss would be less, but the healing process would tend to be longer because cells are being destroyed due to the cauterization effect of the laser. The question is, are these structures produced as an interaction with the laser or are they an intrinsic part of the structure. The effects of the laser interaction upon dentin was studied, and in using electron microscopy the interaction of the excimer laser upon the tooth dentin and other various biological tissue is more clearly understood.

Hammond, Ernest C., Jr.; Gilliam, Ruth L.; Baker, George R.

1989-01-01

414

Selective formation of metastable ferrihydrite in the chiton tooth.  

PubMed

Metastable precursors are thought to play a major role in the ability of organisms to create mineralized tissues. Of particular interest are the hard and abrasion-resistant teeth formed by chitons, a class of rock-grazing mollusks. The formation of chiton teeth relies on the precipitation of metastable ferrihydrite (Fh) in an organic scaffold as a precursor to magnetite. In?vitro synthesis of Fh under physiological conditions has been challenging. Using a combination of X-ray absorption and electron paramagnetic resonance spectroscopy, we show that, prior to Fh formation in the chiton tooth, iron ions are complexed by the organic matrix. In?vitro experiments demonstrate that such complexes facilitate the formation of Fh under physiological conditions. These results indicate that acidic molecules may be integral to controlling Fh formation in the chiton tooth. This biological approach to polymorph selection is not limited to specialized proteins and can be expropriated using simple chemistry. PMID:25196134

Gordon, Lyle M; Román, Jessica K; Everly, R Michael; Cohen, Michael J; Wilker, Jonathan J; Joester, Derk

2014-10-20

415

Selective saturation method for EPR dosimetry with tooth enamel.  

PubMed

The method of selective saturation proposed is based on the difference in the microwave (mw) power dependence of the background and radiation induced EPR components of the tooth enamel spectrum. The subtraction of the EPR spectrum recorded at low mw power from that recorded at higher mw power provides a considerable reduction of the background component in the spectrum. The resolution of the EPR spectrum could be improved 10-fold, however simultaneously the signal-to-noise ratio was found to be reduced twice. A detailed comparative study of reference samples with known absorbed doses was performed to demonstrate the advantage of the method. The application of the selective saturation method for EPR dosimetry with tooth enamel reduced the lower limit of EPR dosimetry to about 100 mGy. PMID:8935967

Ignatiev, E A; Romanyukha, A A; Koshta, A A; Wieser, A

1996-03-01

416

Organic tooth wear--overlooked in anatomy texts.  

PubMed

Most anatomy texts depict gear-like apposition of adult upper and lower teeth. But this apposition generally does not occur in civilized man. On the contrary the widespread tooth attrition which occurs in primitive man, is well established. This attrition, which is not depicted in anatomy texts or correctly evaluated in medical and dental education, is a natural protective mechanism that functions to preserve, oral, pharyngeal, and respiratory physiology throughout life. As man removed grit, sand and other abrasive food from his diet, he deprived himself of a natural aid, i.e. attritional wear of teeth that protects the physiology of his mouth and the swallowing and respiratory apparatus (4). In contrast to this the unworn teeth, characteristic of present-day man, prevent anatomic and physiologic changes that normalize oral pathways. For these reasons, 'textbook' tooth occlusion should be re-evaluated. PMID:1528152

Cooperman, H N

1992-06-01

417

Vital tooth bleaching: biologic adverse effects-a review.  

PubMed

Depending on etiology, the esthetic treatment of dyschromia may involve vital tooth- bleaching techniques. Hydrogen peroxide is the active molecule used for such procedures; however, its action mechanism is not clearly understood. Moreover, a variety of contradictory studies make difficult the evaluation of the safety of bleaching techniques. The purpose of this article is therefore to review the available literature (1) to describe the physicochemical properties of hydrogen peroxide and (2) to assess the safety of its use as a vital tooth-bleaching agent. Indeed, based on hydrogen peroxide's capacity to generate free radicals that diffuse throughout the dental hard tissues, concerns have been addressed regarding the adverse effects that bleaching products can induce on the enamel and dentin structures, pulp, and bonding to a composite resin system. Moreover, during self-application of home bleaching products, hydrogen peroxide is released into the oral cavity and ingested. Some questions have therefore arisen concerning its toxicity and its possible carcinogenicity. PMID:19107251

Minoux, Maryline; Serfaty, Rene

2008-09-01

418

Indication of two Pacific walrus stocks from whole tooth elemental analysis  

USGS Publications Warehouse

The Pacific walrus (Odobenus rosmarus divergens) is considered to be a single panmictic population for management purposes. However, studies on population structuring in this species are limited; in part, because portions of the population's range are often inaccessible. Therefore, alternative and complementary methods for investigating stock structure in the Pacific walrus are of particular interest. We used measures of elemental concentrations in whole tooth sections from ICP-MS in a discriminant analysis to investigate evidence of stock separation between walruses from two of three known breeding areas (S.E. Bering, St Lawrence, and Anadyr Gulf). Elemental compositions of teeth from female and male walruses from the S.E. Bering and St Lawrence breeding areas were significantly different, providing evidence of separate stocks. We also obtained insights into the potential relation of walruses from non-breeding areas to walruses from these breeding groups based on similarities in their dental elemental profiles. ?? 2008 Springer-Verlag.

Jay, C.V.; Outridge, P.M.; Garlich-Miller, J. L.

2008-01-01

419

Canine tooth size and fitness in male mandrills ( Mandrillus sphinx)  

Microsoft Academic Search

Sexual selection theory explains the evolution of exaggerated male morphologies and weaponry, but the fitness consequences of developmental and age-related changes in these features remain poorly understood. This long-term study of mandrill monkeys (Mandrillus sphinx) demonstrates how age-related changes in canine tooth weaponry and adult canine size correlate closely with male lifetime reproductive success. Combining long-term demographic and morphometric data

Steven R. Leigh; Joanna M. Setchell; Marie Charpentier; Leslie A. Knapp; E. Jean Wickings

2008-01-01

420

Herbivore tooth oxygen isotope compositions: Effects of diet and physiology  

Microsoft Academic Search

The applicability of rapid and precise laser probe analysis of tooth enamel for ?18O has been verified, and the method has been applied to different modern herbivores in East Africa. Sampling and pretreatment procedures involve initial bleaching and grinding of enamel to <75 ?m, and elimination of adsorbed water and organic compounds with BrF5. Typical analytical reproducibilities for 0.5–2 mg

Matthew J. Kohn; Margaret J. Schoeninger; John W. Valley

1996-01-01

421

Knee bobbing in Charcot-Marie-Tooth disease  

PubMed Central

Patients with Charcot-Marie-Tooth (CMT) disease most commonly have a slowly progressive neuropathy where ankle dorsiflexion weakness is much more prominent than ankle plantar flexion weakness. The eventual involvement of the ankle plantar flexors has major functional consequences for patients as they lose the ability to stand still. We have found the knee bob sign whereby both knees bob up and down when standing still to be a reliable marker of ankle plantar flexion weakness in CMT. PMID:22661351

Rossor, Alexander M.; Murphy, Sinead; Reilly, Mary M.

2013-01-01

422

Maintenance of tooth color after prophylaxis: comparison of three dentifrices.  

PubMed

Pellicle rapidly accumulates on tooth surfaces after prophylaxis and may acquire cosmetically unacceptable levels of stain. A three-month clinical trial was conducted to evaluate stain prevention by a new silica-based tartar control whitening dentifrice (Crest Extra Whitening) compared to marketed tartar control baking soda peroxide whitening and regular dentifrice controls. Prior to the trial, a one-month screening exercise was conducted to identify adult subjects who accumulated extrinsic tooth stain after dental prophylaxis. A total of 672 subjects were stratified based on tooth whiteness, gender and tobacco usage, then given a dental prophylaxis and randomized into one of three dentifrice treatment groups. All product use was unsupervised. Change in tooth whiteness (delta L*) was determined by comparing colorimeter measurements collected on the facial surfaces of the four central incisors at months 1 and 3 to baseline. Ninety-six percent of subjects completed the three-month study. At both one and three months, the two whitening dentifrices did not differ from baseline in terms of delta L*. In contrast, the regular control had delta L* values of -0.26 and -0.39 at one and three months, respectively, differing significantly from baseline at both time points. Each of the whitening dentifrices differed statistically from the regular control in stain accumulation (p < or = 0.001) at one and three months, but were not different from each other. In general, all three test dentifrices were well tolerated. These data demonstrate the effectiveness of the new tartar control whitening dentifrice in preventing stain accumulation after dental prophylaxis compared to the marketed regular dentifrice control. PMID:11476015

Isaacs, R L; Bartizek, R D; Owens, T S; Walters, P A; Gerlach, R W

2001-01-01

423

Intra-tooth variations in ? 18O (PO 4) of mammalian tooth enamel as a record of seasonal variations in continental climate variables  

Microsoft Academic Search

Regular intra-tooth variations in the ?18O value of mammalian tooth enamel phosphate (?18Op) have been considered a potential measure of seasonal changes in continental climate variables since they were first observed. In order to investigate this possibility in more detail, analyses were made of teeth from a number of mammalian herbivores (sheep, cattle, elk, and pigs) that lived over a

Henry C Fricke; William C Clyde; James R O’Neil

1998-01-01

424

New population of odontoblasts responsible for tooth root formation.  

PubMed

Root formation is initiated with the extension of Hertwig's epithelial root sheath (HERS) after crown morphogenesis. To date, little is known about the molecular and cellular mechanisms controlling root formation. Recently we found rootless molars are formed in the dental mesenchyme-specific ?-catenin conditional knockout mice. The striking root phenotypes of these mutant mice result from the disrupted differentiation of differentiating odontoblasts, caused by ablation of ?-catenin during initiation of root formation. Here we show the cellular and molecular characteristics of differentiating odontoblasts using histochemistry and immunohistochemistry. These cells were not found in crown formation, but appeared only in the apical end of developing tooth, thus we have named these cells "apical odontoblasts" (AOds). AOds appeared immediately after HERS formation and were always present on the apical side of developing roots until root formation was complete. These findings indicate that AOds are closely associated with the transition from crown to root and with root elongation. In AOds, several transcription factors, including Nfic, Creb3l1, and Osx, as well as ?-catenin and alkaline phosphatase were expressed but Phex and Dspp were not expressed. Taken together, our results indicate that AOds are the principal cells responsible for tooth root formation. These findings may contribute to the further understanding of the mechanisms underlying tooth root formation and root regeneration. PMID:23603379

Bae, Cheol-Hyeon; Kim, Tak-Heun; Chu, Jung-Yob; Cho, Eui-Sic

2013-01-01

425

[Case of reimplanted tooth with long-lasting clinical effect].  

PubMed

The author describes a case of reimplantation of 44 of a 35-year-old woman, 19 years ago. Later, 10 years after the reimplantation apical osteotomy, according to indications, was performed to the same tooth. The X-ray, performed in 1985, shows that resorptive processes around the tooth and root has not advances as yet. It started after the root treatment on the adjecent 46 in 1985. The author thinks that the mass failure of teeth reimplantation (short-term therapeutic effect of 5-6 years and not with all reimplantations) reduces the interest of the researchers in it without any grounds. The case described shows that, very likely, under certain conditions and certain operation technique, unconsciously blended in the case described, very good therapeutic effect could be relied on via the reimplantation. It is presumed that the initiation of resorption has been provoked by the devitalization of an adjacent tooth, possibly due to disturbed trophicity in the region around it. It has been concluded that a great many problems, still unknown, of teeth reimplantation wait their proper solution. PMID:3274198

Nedkov, R

1988-01-01

426

Developmental genetic mechanisms of evolutionary tooth loss in cypriniform fishes.  

PubMed

The fossil record indicates that cypriniform fishes, a group including the zebrafish, lost oral teeth over 50 million years ago. Despite subsequent diversification of feeding modes, no cypriniform has regained oral teeth, suggesting the zebrafish as a model for studying the developmental genetic basis of evolutionary constraint. To investigate the mechanism of cypriniform tooth loss, we compared the oral expression of seven genes whose mammalian orthologs are involved in tooth initiation in the zebrafish and the Mexican tetra, Astyanax mexicanus, a related species retaining oral teeth. The most significant difference we found was an absence in zebrafish oral epithelium of expression of dlx2a and dlx2b, transcription factors that are expressed in early Astyanax odontogenic epithelium. Analysis of orthologous genes in the Japanese medaka (Oryzias latipes) and a catfish (Synodontis multipunctatus) suggests that expression was lost in cypriniforms, rather than gained in Astyanax. Treatment of Astyanax with an inhibitor of Fibroblast growth factor (Fgf) signaling produced a partial phenocopy of the zebrafish oral region, in that oral teeth, and expression of dlx2a and dlx2b, were lost, whereas shh and pitx2, genes whose expression is present in zebrafish oral epithelium, were unaffected. We hypothesize that a loss of Fgf signaling to oral epithelium was associated with cypriniform tooth loss. PMID:16831836

Stock, David W; Jackman, William R; Trapani, Josh

2006-08-01

427

Tooth whitening in children and adolescents: a literature review.  

PubMed

The purpose of this paper was to summarize the findings of a literature review on the use of peroxide-based tooth-whitening agents in children and adolescents. Safety considerations, including localized adverse effects and toxicological concerns, are described. Oral findings include: (1) 1 in every 2 to 3 patients may experience tooth sensitivity and/or gingival irritation after bleaching treatment, which may be more traumatic an experience for children than adults; (2) depending on dose, duration, frequency, and route, studies indicate excessive exposure to peroxide can be potentially harmful; (3) degree of potential toxicity and harmful outcomes increases in those who overuse whiteners--a concern in teenagers; (4) careful case selection using stringent criteria is suggested for primary teeth whitening; (5) whitening in healthy adolescents is a case-by-case determination that must include the weighing of risks (oral health and age) vs benefits (improved esthetic perception). It is hoped that the present review will lead to a better understanding of the health implications of tooth whitening in children and adolescents, and offer guidance for treatment that provides satisfactory outcomes externally (enamel and gingiva) and internally (endodontic tissues and systemic health). PMID:16435634

Lee, Sean S; Zhang, Wu; Lee, D Harvey; Li, Yiming

2005-01-01

428

Estimation of Tooth Size Discrepancies among Different Malocclusion Groups  

PubMed Central

ABSTRACT Regards and Tribute: Late Dr Narender Hasija was a mentor and visionary in the light of knowledge and experience. We pay our regards with deepest gratitude to the departed soul to rest in peace. Bolton’s ratios help in estimating overbite, overjet relationships, the effects of contemplated extractions on posterior occlusion, incisor relationships and identification of occlusal misfit produced by tooth size discrepancies. Aim: To determine any difference in tooth size discrepancy in anterior as well as overall ratio in different malocclusions and comparison with Bolton’s study. Materials and methods: After measuring the teeth on all 100 patients, Bolton’s analysis was performed. Results were compared with Bolton’s means and standard deviations. The results were also subjected to statistical analysis. Results show that the mean and standard deviations of ideal occlusion cases are comparable with those Bolton but, when the mean and standard deviation of malocclusion groups are compared with those of Bolton, the values of standard deviation are higher, though the mean is comparable. How to cite this article: Hasija N, Bala M, Goyal V. Estimation of Tooth Size Discrepancies among Different Malocclusion Groups. Int J Clin Pediatr Dent 2014;7(2):82-85.

Bala, Madhu; Goyal, Virender

2014-01-01

429

[Dental implants and their materials].  

PubMed

Some new trends in materials for dental implants, which also effect in the operative techniques and implant design, are described. Advantages and shortcomings of the different material types are exemplified and correlated with their bioinert resp. bioactive functions. The practical interest in metallic implants focussed in titanium resp. oxide ceramics in the ceramic field, whereas the special goal of implant research follows from the improvement of the bioactive principle with loaded calcium phosphate implants. PMID:6350895

Newesely, H

1983-07-01

430