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1

Adult growth, aging, and the single-tooth implant.  

PubMed

Single-tooth implants are an increasingly popular method for replacing single teeth. While the effects of growth on implants in children have been well documented, the changes that occur in adults have not been studied with respect to single-tooth implants. It has been assumed that adults are stable and do not change; however, research in the last few years has indicated that adults do change with aging, and adult growth does occur. The changes in adults occur over decades rather than rapidly, as seen in children. Aging changes are readily apparent in the soft tissues of the face and create dramatic changes. Changes in the jaws and teeth occur as a result of continued, slow growth, in contrast to the aging effects seen in soft tissues. Growth changes occur in the arches and result in adaptive changes in the teeth over time, both vertically and horizontally, and in alignment. These dental changes may result in a lack of occlusion vertically or malposition of adjacent natural teeth relative to the implant crown. Clinicians may be well advised to observe and report these changes and warn patients that changes can occur over the service life of the implant-supported crown. These changes may require maintenance adjustments or possible remaking of the implant crown as a result of adult growth, wear, or the esthetic changes of aging. PMID:10795458

Oesterle, L J; Cronin, R J

2

Retrospective Cross Sectional Comparison of Initial Nonsurgical Endodontic Treatment and Single-Tooth Implants  

Microsoft Academic Search

Initial root canal treatment and the replacement of a single tooth with implants are both viable treatment options, but various success rates have been reported for each treatment modality. This study compared 196 implant restorations and 196 matched initial nonsurgi- cal root canal treatment (NSRCT) teeth in patients for four possible outcomes- success, survival, survival with subsequent treatment intervention and

Scott L. Doyle; James S. Hodges; Igor J. Pesun; Alan S. Law; Walter R. Bowles

3

Retrospective Cross Sectional Comparison of Initial Nonsurgical Endodontic Treatment and Single-Tooth Implants  

Microsoft Academic Search

Initial root canal treatment and the replacement of a single tooth with implants are both viable treatment options, but various success rates have been reported for each treatment modality. This study compared 196 implant restorations and 196 matched initial nonsurgical root canal treatment (NSRCT) teeth in patients for four possible outcomes- success, survival, survival with subsequent treatment intervention and failure.

Scott L. Doyle; James S. Hodges; Igor J. Pesun; Alan S. Law; Walter R. Bowles

2006-01-01

4

A retrospective multicenter evaluation of single tooth implant experience at three centers in the United Kingdom  

Microsoft Academic Search

Statement of problem. Implant treatment in the United Kingdom has been provided mainly in specialist, regional dental hospitals. However, increasingly, general dentists are providing implant-supported prostheses in a private office setting.Purpose. This study investigated the nature, timing, and frequency of complications associated with single tooth implant therapy in a dental hospital and two dental offices.Methods. The dental records of 58

A. S. McMillan; P. F. Allen; I. Bin Ismail

1998-01-01

5

Immediate, non-submerged, root-analogue zirconia implant in single tooth replacement  

Microsoft Academic Search

This report demonstrates the successful clinical use of a modified root-analogue zirconia implant for immediate single tooth replacement. A right maxillary premolar was removed and a custom-made, root-analogue, roughened zirconia implant with macro-retentions in the interdental space was fabricated and placed into the extraction socket 4 days later. Four months after root implantation a composite crown was cemented. No complications

W. Pirker; A. Kocher

2008-01-01

6

In vitro comparison of master cast accuracy for single-tooth implant replacement  

Microsoft Academic Search

Statement of Problem: The inaccuracy in transferring the position of the hexagonal head of a single implant to the working cast can result in a final single tooth crown, which clinically may present occlusal and\\/or interproximal contacts that are different from those contacts on the master cast obtained by the technician. Purpose: This in vitro study evaluated the accuracy of

Paolo Vigolo; Zeina Majzoub; Giampiero Cordioli

2000-01-01

7

The Single-tooth Implant Treatment of Congenitally Missing Maxillary Lateral Incisors Using Angled Abutments: A Clinical Report  

PubMed Central

The maxillary lateral incisor is the second most common congenitally absent tooth. There are several treatment options for replacing the missing maxillary lateral incisor, including canine substitution, tooth-supported restoration, or single-tooth implant. Dental implants are an appropriate treatment option for replacing missing maxillary lateral incisor teeth in adolescents when their dental and skeletal development is complete. This case report presents the treatment of a patient with congenitally missing maxillary lateral incisors using dental implants with angled abutments.

Tuna, Suleyman Hakan; Keyf, Filiz; Pekkan, Gurel

2009-01-01

8

Surgical Tooth Implants, Combat and Field.  

National Technical Information Service (NTIS)

Long term implant studies of alumina tooth roots are being performed in both humans and baboons. The implants designed for this project are single root elliptical and rectangular designs with serrations arranged for maximal stress distribution of occlusal...

C. R. Hassler R. H. Downes G. L. Messing O. E. Russell

1978-01-01

9

Surgical Tooth Implants, Combat and Field.  

National Technical Information Service (NTIS)

Long term implant studies of alumina tooth roots are being performed in both humans and baboons. The implants designed for this project are a single root rectangular design with serrations arranged for maximal stress distribution of occlusal loads. THe im...

C. R. Hassler R. M. Downes L. G. McCoy

1981-01-01

10

Cemented Versus Screw-Retained Implant-Supported Single-Tooth Crowns: A 4-year Prospective Clinical Study  

Microsoft Academic Search

Purpose: The purpose of this controlled prospective clinical study was to compare cemented and screw-retained implant-supported single-tooth crowns followed for 4 years following prosthetic rehabili- tation with respect to peri-implant marginal bone levels, peri-implant soft tissue parameters, and pros- thetic complications. Materials and Methods: Twelve consecutive patients were selected from a patient population attending the Implantology Department at the University

Paolo Vigolo; Andrea Givani; Zeina Majzoub; Giampiero Cordioli

11

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

12

Master Cast Accuracy in Single-Tooth Implant Replacement Cases: An In Vitro Comparison. A Technical Note  

Microsoft Academic Search

Purpose: This in vitro study evaluated the accuracy of master casts obtained by using (1) copings mod- ified by sandblasting and coating their roughened surfaces with impression adhesive before final impression procedures and (2) gold machined UCLA abutments as impression copings in final impres- sion procedures for single-tooth implant replacement cases. Materials and Methods: A polymeric resin model with a

Paolo Vigolo; Fulvio Fonzi; Zeina Majzoub; Giampiero Cordioli

13

Factors affecting outcomes for single-tooth implants and endodontic restorations.  

PubMed

Initial root canal therapy and implant placement are both common treatment modalities, and, as such, prognostic factors that influence the treatment outcomes of these two restorations should be identified. In a retrospective chart review, 196 implant restorations and 196 matched initial nonsurgical root canal treated (NSRCT) teeth in patients were evaluated for four possible outcomes-success, survival, survival with intervention, and failure. Results showed that smokers had fewer successes and more failures in both groups (p = 0.0001), whereas NSRCT outcomes were affected by periradicular periodontitis (p = 0.001), post placement (p = 0.013), and overfilling (p = 0.003). Outcomes for both groups were not significantly affected by diabetes, age, or gender. Implant group outcomes were not affected by implant length (from 10 to 16 mm), diameter (from 3.25 to 5.5 mm), or an adjacent endodontically treated tooth, nor were NSRCT outcomes affected by the number of appointments for the procedure. PMID:17368326

Doyle, Scott L; Hodges, James S; Pesun, Igor J; Baisden, Michael K; Bowles, Walter R

2007-02-23

14

Fracture resistance of single-tooth implant-supported zirconia-based indirect composite-layered molar restorations.  

PubMed

OBJECTIVES: This study evaluated the fracture resistance of single-tooth implant-supported zirconia-based indirect composite-layered molar restorations. MATERIAL AND METHODS: Forty-four titanium abutments (GingiHue Post) were placed on dental implants (Osseotite Implant). Standardized single-tooth cement-retained implant-supported mandibular molar restorations were fabricated for each of four test groups (n = 11) as follows: porcelain-fused-to-metal crowns (PFM), zirconia-based all-ceramic crowns (ZAC), zirconia-based indirect composite-layered crowns primed with Estenia Opaque Primer for zirconia frameworks (ZIC-E), and zirconia-based indirect composite-layered crowns (ZIC). The crowns were luted with a glass-ionomer cement (Ketac Cem Easymix). Fracture resistance (N) was determined by force application of a perpendicular load to the crowns with a universal testing machine. One-way analysis of variance (ANOVA) and the Tukey's HSD test were used to assess differences in fracture resistance values (? = 0.05). RESULTS: Mean fracture resistances (SD) were 3.09 (0.22) kN, 3.11 (0.34) kN, 2.84 (0.21) kN, and 2.50 (0.36) kN for the PFM, ZAC, ZIC-E, and ZIC groups, respectively. Fracture resistance in the ZIC specimens was significantly lower (P < 0.044) than that in the other groups, which did not significantly differ. CONCLUSIONS: The fracture resistance of single-tooth implant-supported zirconia-based indirect composite-layered molar crowns primed with Estenia Opaque Primer for zirconia frameworks (ZIC-E) is comparable to that of porcelain-fused-to-metal (PFM) and zirconia-based all-ceramic (ZAC) restorations. Application of Estenia Opaque Primer to zirconia ceramic framework provides superior fracture resistance in implant-supported zirconia-based indirect composite-layered molar crowns. PMID:23730807

Taguchi, Kohei; Komine, Futoshi; Fushiki, Ryosuke; Blatz, Markus B; Kamio, Shingo; Matsumura, Hideo

2013-06-01

15

Cumulative survival rate and complication rates of single-tooth implant; focused on the coronal fracture of fixture in the internal connection implant.  

PubMed

This retrospective study evaluated the 5-year cumulative survival rate and complication rates of a 4·0-mm internal connection implant (MicroThread™ Osseospeed™, Astra Tech) installed for single-tooth restoration. The patients who were treated at Asan Medical Center between 2006 and 2007 were included in this study. A life table analysis was used to calculate the 5-year cumulative survival rate. Comparisons of cumulative survival rates among implant position (anterior, premolar and molar), jawbone (maxilla, mandible), gender and prosthesis type (screw-retained, cement-retained) were performed using the log-rank test. Post-loading complications were analysed using Fisher's exact test. Twelve of 136 implants (anterior; 22, premolar; 25, molar; 89) were lost during the loading period, and 11 were removed due to coronal fracture of fixture. The 5-year cumulative survival rate of the whole arch was 91·9%, and that of the molar region was 87·6%. Statistically significant differences were observed in cumulative survival rates among implant position (P = 0·037), whereas no statistically significant differences were observed among gender, jawbone, prosthesis type. Forty-seven of 114 (41·2%) implants in the posterior region showed post-loading complications, including coronal fracture of fixture and abutment screw loosening. PMID:23679929

Cha, H-S; Kim, Y-S; Jeon, J-H; Lee, J-H

2013-05-16

16

Factors Affecting Outcomes for Single-Tooth Implants and Endodontic Restorations  

Microsoft Academic Search

Initial root canal therapy and implant placement are both common treatment modalities, and, as such, prognostic factors that influence the treatment outcomes of these two restorations should be identified. In a retrospective chart review, 196 implant restorations and 196 matched initial nonsurgical root canal treated (NSRCT) teeth in patients were evaluated for four possible outcomes—success, survival, survival with intervention, and

Scott L. Doyle; James S. Hodges; Igor J. Pesun; Michael K. Baisden; Walter R. Bowles

2007-01-01

17

Factors Affecting Outcomes for Single-Tooth Implants and Endodontic Restorations  

Microsoft Academic Search

Initial root canal therapy and implant placement are both common treatment modalities, and, as such, prog- nostic factors that influence the treatment outcomes of these two restorations should be identified. In a retro- spective chart review, 196 implant restorations and 196 matched initial nonsurgical root canal treated (NSRCT) teeth in patients were evaluated for four possible out- comes—success, survival, survival

Scott L. Doyle; James S. Hodges; Igor J. Pesun; Michael K. Baisden; Walter R. Bowles

18

Soft tissue modeling for the esthetic single-tooth implant restoration.  

PubMed

The ability of the restorative dentist to understand and control the relation of the implant to its associated gingival tissues is extremely important in achieving the maximum esthetic result in the final restoration. The position of the gingival margin following stage-two surgery represents collapse of the gingival tissues until it finds support by the component against which it comes to rest. This component may be a healing abutment, final abutment, or provisional restoration, if placed at the same time of implant exposure. Generally, it will be a healing abutment. There is complex relation between implant position, gingival management at stage-one and stage-two surgery, the position of the gingival margin over the buccal surface of the implant compared to the adjacent natural teeth, component selection, and lip line esthetics. The therapist who understands these relations will know how to mold the gingival tissue around implants to maximize the esthetic result. This article focuses on these relations and the technique of tissue modeling with subgingival contours to create a restoration with the illusion of reality. PMID:9759029

Potashnick, S R

1998-01-01

19

Esthetic outcome of an immediately placed maxillary anterior single-tooth implant restored with a custom-made zirconia-ceramic abutment and crown: a staged treatment.  

PubMed

This article describes the high esthetic value of a single-tooth implant immediately placed in the anterior region using a flapless approach and a custom-made zirconia-ceramic abutment and crown. The case reported illustrates the practical procedure involved in developing natural esthetics with a custom-made zirconia-ceramic prosthesis and abutment. The technique is relatively simple, can be used in a variety of clinical situations, and provides excellent results from an esthetic point of view, which is demonstrated by the results of pink esthetic scores (PES) (9 ± 0.2) and white esthetic scores (WES) (7 ± 0.5) after 4 years. PMID:21359243

Traini, Tonino; Pettinicchio, Marzia; Murmura, Giovanna; Varvara, Giuseppe; Di Lullo, Nicola; Sinjari, Bruna; Caputi, Sergio

2011-02-01

20

A Review of Factors Influencing Treatment Planning Decisions of Single-tooth Implants versus Preserving Natural Teeth with Nonsurgical Endodontic Therapy  

Microsoft Academic Search

One of the major issues confronting the contemporary dental clinician is the treatment decision between extracting a tooth with placement of a dental implant or preserving the natural tooth by root canal treatment. The factors that dictate the correct selection of one procedure over the other for each particular case are not yet established by randomized controlled studies. The aim

Mian K. Iqbal; Syngcuk Kim

2008-01-01

21

Peri-Implant Diseases  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

22

Use of Metallic Endosseous Implants as a Tooth Substitute.  

National Technical Information Service (NTIS)

The objective of the study is to evaluate the viability of an artificial metallic prosthesis as a tooth replacement when placed permanently into the jaw bone. The tooth substitute consists of two parts: (1) the root portion, a metallic implant with an ope...

M. B. Weiss W. Rostoker

1979-01-01

23

The Effect of Currently Available Surgical and Restorative Interventions on Reducing Mid-facial Mucosal Recession of Single-Tooth Immediate Placed Implants: A Systematic Review.  

PubMed

Aims: Procedures to improve peri-implant soft tissue outcomes of single immediately placed implants are a topic of interest. This systematic review aimed to investigate the effect of various surgical and restorative interventions on mid-buccal mucosal level of the implants. Material and Methods: An electronic search of 5 databases (1990-2012 Dec) and a hand search of peer-reviewed journals for relevant articles were performed. Randomized controlled clinical trials (RCTs), prospective cohort studies, and case series with at least 9 participants, with data on mid-facial mucosal recession (MR) of immediately placed implants following various surgical and restorative interventions with a follow-up period for at least 6 months were included. Results: Thirty-six studies, 8 RCTs, 1 cohort study and 27 case series were eligible. Six interventions were identified and reviewed: (1) palatal/lingual implant position, (2) platform-switched abutments, (3) bone grafts to fill the gap between the buccal plate and fixture, (4) the flapless approach, (5) connective tissue grafts (CTG), and (6) immediate provisionalization. Three publications consistently showed that palatally/lingually positioned implants had significantly less MR when using tissue level implants. Mixed results were reported for interventions (2), (4), (5) and (6). One study was available for intervention (3) and did not show a benefit. Conclusions: Some interventions might be adopted to reduce the amount of MR on implants with the immediate placement approach, as suggested by the included publications with various level of evidence. The conflicting results among studies might be a result of differences in patient and site characteristics, e.g. tissue biotype and buccal plate thickness. Therefore, the use of these interventions might be reserved for patients with moderate to high risk of esthetic complications. PMID:23578250

Lin, Guo-Hao; Chan, Hsun-Liang; Wang, Hom-Lay

2013-04-11

24

[Treatment of a single-tooth space in the occlusal system].  

PubMed

The space created by the absence of 1 not-free-ending tooth in an occlusal system can be indicated as a single-tooth space. For treating a single-tooth space, several options are available to restore the functions of the occlusal system. Feasible options are a resin-bonded fixed prosthesis, a conventional fixed prosthesis, and an implant-supported restoration. Implant-supported restorations have a good prognosis, high patient satisfaction, and the advantage that adjacent teeth are not involved in the treatment. Anxiety about surgical treatment, the width of the single-tooth space, and financial aspects may be reasons not to consider an implant-supported restoration as first-choice treatment. PMID:23373307

Meijer, H J A; Cune, M S

2012-12-01

25

Biomechanical considerations on tooth-implant supported fixed partial dentures  

PubMed Central

This article discusses the connection of teeth to implants, in order to restore partial edentulism. The main problem arising from this connection is tooth intrusion, which can occur in up to 7.3% of the cases. The justification of this complication is being attempted through the perspective of biomechanics of the involved anatomical structures, that is, the periodontal ligament and the bone, as well as that of the teeth- and implant-supported fixed partial dentures.

Calvani, Pasquale; Hirayama, Hiroshi

2012-01-01

26

Single-tooth replacement: factors affecting different prosthetic treatment modalities  

PubMed Central

Background The choice between several treatment options for replacing a single missing tooth is influenced by clinical, dentist- and patient-immanent factors. This study aimed to determine the patient factors that would affect the treatment decision to replace a single missing tooth and to assess the satisfaction with several options. Method 200 volunteers involved (121 females and 79 males) divided into four groups, Group A: consisted of patients with conventional fixed partial dentures or patients with resin bonded fixed partial dentures. Group B: consisted of patients who received removable partial dentures while Group C: consisted of patients who received a single implant supported crown, and a control group D: consisted of patients who received no treatment. Data were collected using a questionnaire. Results The highest percentage of males within groups (58%) was within the removable prostheses category. The majority of the subjects in the study reported that the main reason for replacing a missing tooth was for esthetic and function. Most important factor affecting the choice between treatment modalities was damaging the neighboring teeth. Pain, post operative sensitivity and dental phobia were important factors in choosing the prosthesis type and affected the control group patients not to have any treatment. The highest satisfaction percentage among groups studied was recorded for dental implants then FPD groups, while the least percentage were in both the control and RPD groups, for all aspects of function, esthetic and speech efficiency. Conclusions The final choice between FPD, RPD and implant depended on several factors which affected the decision making; among these is cost and patients' awareness of the different treatment options.

2011-01-01

27

Endosseous titanium implants as anchors for mesiodistal tooth movement in the beagle dog  

Microsoft Academic Search

The purpose of this study was to determine the anchorage potential of titanium implants (Brånemark; 3.75 × 7 mm) with the use of a sectional arch wire technique for orthodontic mesiodistal tooth movement, as assessed by the osseointegration of implants and tooth movement. Two implants were surgically placed in healed mandibular extraction sites of the second and third premolars on

Shigeru Saito; Naoko Sugimoto; Tomio Morohashi; Masahiko Ozeki; Hitomi Kurabayashi; Hiroshi Shimizu; Ken-ichi Yamasaki; Akihiko Shiba; Shoji Yamada; Yoshinobu Shibasaki

2000-01-01

28

Fracture behaviour of implant–implant- and implant–tooth-supported all-ceramic fixed dental prostheses utilising zirconium dioxide implant abutments  

Microsoft Academic Search

This in vitro study investigated the fracture behaviour of implant–implant-supported and implant–tooth-supported all-ceramic\\u000a fixed dental prostheses (FDP) using zirconium dioxide implant abutments (FRIADENT® CERCON® abutments, DENTSPLY Friadent).\\u000a Six different test groups (n?=?8) were prepared. Groups 1, 2, 4, and 5 represented an implant–implant-supported FDP condition, whereas groups 3 and 6\\u000a simulated an implant–tooth-supported FDP condition. The second right premolar of

Frank Philipp Nothdurft; Sabine Merker; Peter Reinhard Pospiech

2011-01-01

29

Immediate implants following tooth extraction. A systematic review  

PubMed Central

Objectives: The aim of this article is to review the current state of immediate implants, with their pros and contras, and the clinical indications and contraindications. Material and Methods: An exhaustive literature search has been carried out in the COCHRANE library and MEDLINE electronic databases from 2004 to November 2009. Randomized clinical trials and clinical trials focused on single implants placed in fresh extraction sockets were included and compared. A meta-analysis could not be performed due to heterogeneity of the data. Results: Twenty studies out of 135 articles from the initial search were finally included, which summed up a total of 1139 immediate implants with at least a 12-month follow-up. Our results have been compared with other current available papers in the literature reviewed that obtained similar outcomes. Discussion: Immediate implants have predictable results with several advantages over delayed implant placement. However, technical complications have been described regarding this technique. Also, biomaterials may be needed when the jumping distance is greater than 1mm or any bone defect is present. Conclusions: Few studies report on success rates rather than survival rates in the literature reviewed. Short-term clinical results were described and results were comparable to those obtained with delayed implant placement. Further long-term, randomized clinical trials are needed to give scientific evidence on the benefits of immediate implants over delayed implant placement. Key words:Immediate implants, fresh socket, dental implants, gap, jumping distance, implant stability.

Perez-Pascual, Tania; Mareque-Bueno, Santiago; Hernandez-Alfaro, Federico; Ferres-Padro, Eduard

2012-01-01

30

Simplified orthodontic tooth movement with dental implants and orthodontic elastics: a clinical report.  

PubMed

Lack of adequate mesiodistal space and/or incorrect implant placement may not provide adequate space for the fabrication, insertion, and maintenance of implant crowns. This report describes the clinical presentation of a patient requiring restoration of a dental implant without adequate interproximal space due to mesial drift of the adjacent tooth. Orthodontic tooth movement was achieved with an osseointegrated dental implant and orthodontic elastics. PMID:21640236

Rotella, Mario; Geminiani, Alessandro; Ercoli, Carlo

2011-06-01

31

Rehabilitation using single stage implants  

PubMed Central

Implant related prosthesis has become an integral part of rehabilitation of edentulous areas. Single stage implant placement has become popular because of its ease of use and fairly predictable results. In this paper, we present a series of cases of single stage implants being used to rehabilitate different clinical situations. All the implants placed have been successfully restored and followed up for up to one year.

Mohamed, Jumshad B.; Sudarsan, Sabitha; Arun, K. V.; Shivakumar, B.

2009-01-01

32

[Clinical study of tooth-to-implant supported fixed partial dentures].  

PubMed

The lack of the periodontal ligaments around the implants results an ankylotic fixation. The mobility of the osseointegrated implants is only one tenth of the mobility of the natural teeth. To connect a natural tooth and an implant as abutments in a fixed restoration is a special problem in the dentistry. The aim of this study was to examine whether connecting of implants and natural teeth has any disadvantages for the abutment either implant or natural tooth. Furthermore we wanted to know if an overloading of the opposing tooth could occur because of the stiffness of the implant-bone connection. 21 partially edentulous patients, who were treated with implant supported bridges using the DenTi implant system which includes screw-shaped, commercially pure titanium implants, were examined. Plaque, calculus, gingival index, probing depth and bleeding on probing were recorded around the implants and the teeth. Mobility, sound on percussion were examined as well. In this study no disadvantageous effect of connecting teeth to implants as abutments by fixed partial dentures was found. There was no sign of a harmful effect of the implant to the opposing teeth either. The tooth-to-implant bridges function in their biological environment without affecting it adversely. PMID:9704564

Radnai, M; Fazekas, A; Vajdovich, I; Kostinek, D

1998-07-01

33

Mini-implant insertion based on tooth crown references: a guide-free technique  

Microsoft Academic Search

Mini-implant insertion requires accurate surgical technique. This study shows an insertion technique using only tooth crown references; its scientific basis is evaluated radiographically. The sample consisted of 213 inter-radicular septa, evaluated in 53 bitewing radiographs. The proximal contour of adjacent tooth crowns was used to define septum width. The midpoint of the septum width was linked to the interdental contact

S. Estelita; G. Janson; K. Chiqueto; D. Garib

34

Treatment outcome of immediate, early and conventional single-tooth implants in the aesthetic zone: a systematic review to survival, bone level, soft-tissue, aesthetics and patient satisfaction  

Microsoft Academic Search

Aim: This study evaluated, through a systematic review of the literature, the outcome of single-implant restorations in the aesthetic zone with natural adjacent teeth, thereby addressing immediate, early and conventional implant approaches. Material and Methods: MEDLINE (1950-2008), EMBASE (1966-2008), and CENTRAL (1800-2008) were searched to identify eligible studies. Two reviewers independently assessed the methodological quality using specific study-design-related assessment forms.

Laurens den Hartog; James J. R. Huddleston Slater; Arjan Vissink; Henny J. A. Meijer; Gerry M. Raghoebar

2008-01-01

35

Mechanical considerations for the implant tooth-supported fixed partial denture.  

PubMed

The implant tooth-supported fixed partial denture presents a biomechanical design problem, because the implant is rigidly fixed within the alveolus, and the tooth is surrounded by a periodontal ligament that allows movement. Nonrigid fixed partial denture designs are advocated by some dentists as a method of compensating for this differential movement. Rigid fixed partial denture designs, however, are advocated by many clinicians. Studies have failed to show the advantage of one design over the other. This study developed an in vitro method for testing such prosthesis designs and measured movement of a natural tooth abutment during simulated function. The movement of the natural tooth abutment was not found to change substantially with the fixed partial denture designs tested. PMID:8809254

Breeding, L C; Dixon, D L; Sadler, J P; McKay, M L

1995-11-01

36

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.

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

2013-01-01

37

Tooth-implant connection: some biomechanical aspects based on finite element analyses.  

PubMed

This study investigated, with the use of two- and three-dimensional finite element analysis, the peri-implant stress that occurred during loading of a tooth that was rigidly connected to a distally placed implant. A fixed bond between the bone and the implant was assumed, while the periodontal ligament was represented by means of three-dimensional nonlinear visco-elastic spring elements. Two different loading conditions were compared in the study: i) an axially directed static load of 50 kg that was applied to the tooth for 10 s, and ii) a transitional load of 50 kg that was applied for 5 milliseconds. Load duration appeared to have a greater influence than load intensity on the stress distribution in the bone around an implant and a rigidly connected tooth. Static load is, therefore, potentially more harmful for peri-implant bone than transitional load. The periodontal ligament seems to play a key role in the stress distribution between a tooth and a rigidly connected implant. PMID:12010166

Menicucci, Giulio; Mossolov, Alexei; Mozzati, Marco; Lorenzetti, Massimo; Preti, Giulio

2002-06-01

38

Telescopic overdenture supported by a combination of tooth and an implant: a clinical report.  

PubMed

The conventional modality of treatment of partial edentulousness with reduced number of teeth was to render them complete edentulous and provide them complete denture or an overdenture with support of few remaining teeth. The goal of maintenance of roots are to prevent alveolar bone resorption, provide better load transmission, maintain sensory feedback and achieve better stability of denture with emphasis on psychological aspect of not being completely edentulous. Over the recent past titanium dental implants have been successfully used as tooth replacement with predictable results. A combination of tooth and implant support is well documented for fixed partial dentures but rarely for overdentures. This clinical report aims at evaluation of tooth root and implant supported mandibular overdenture treatment with telescopic coping. PMID:22131669

Abraham, Ponsekar A; Koka, Pradeep; Murugesan, K; Vasanthakumar, M

2010-12-09

39

Influence of Implant Position on Clinical Crown Length and Peri-implant Soft Tissue Dimensions at Implant-Supported Single Crowns Replacing Maxillary Central Incisors.  

PubMed

The aims of this study were to evaluate the influence of implant position on clinical crown length and marginal soft tissue dimensions at implant-supported single crowns of maxillary central incisors and to validate the papilla index score (PIS). Twenty-five patients were included. Standardized and clinical photographs and periapical radiographs from baseline were used to assess three-dimensional positional parameters. The contralateral central incisors were used as controls. Paired sample t test and Pearson correlation analysis were used to analyze implant position, dimension of crown, and papilla fill. Cohen ? and Spearman correlation were used to validate the PIS. The implant-supported crown was statistically significantly longer than the contralateral tooth, and there was significant correlation between the orofacial position of the implant and the crown length difference. The distal papilla was significantly shorter than the mesial papilla at implant-supported crowns, but this difference was not significant at the contralateral tooth. A significant relationship between the PIS and papilla fill was found. An implant protruding the mucosa in a buccal position will result in an increased implant crown length compared to the contralateral tooth. Minor buccal angulations of the implant could be corrected with customized angulated abutments and did not necessarily result in an increased crown length. The distal implant papilla height was obviously shorter, although the mesial papilla height was similar to that of the healthy dentition. The PIS was found to be a valid index for papilla fill. PMID:24116357

Peng, Min; Fei, Wei; Hosseini, Mandana; Gotfredsen, Klaus

40

An Investigation of Three types of Tooth Implant Supported Fixed Prosthesis Designs with 3D Finite Element Analysis  

PubMed Central

Objective: Tooth/implant supported fixed prostheses may present biomechanical design problems, as the implant is rigidly anchored within the alveolus, whereas the tooth is attached by the periodontal ligament to the bone allowing movement. Many clinicians prefer tooth/implant supported fixed prosthesis designs with rigid connectors. However, there are some doubts about the effect of attachment placement in different prosthesis designs. The purpose of this study was to examine the stresses accumulated around the implant and natural teeth under occlusal forces using three dimensional finite element analysis (3D FEA). Materials and Methods: In this study, different connection designs of tooth/implant fixed prosthesis in distal extension situations were investigated by 3D FEA. Three models with various connection designs were studied; in the first model an implant rigidly connected to an abutment, in the second and third models an implant connected to abutment tooth with nonrigid connector in the distal part of the tooth and mesial part of the implant. In each model, a screw type implant (5×11mm) and a mandibular second premolar were used. The stress values of these models loaded with vertical forces (250N) were analyzed. Results: There was no difference in stress distribution around the bone support of the implant. Maximum stress values were observed at the crestal bone of the implant. In all models, tooth movement was higher than implant movement. Conclusion: There is no difference in using a rigid connector, non rigid connector in the distal surface of the tooth or in the mesial surface of an implant.

Koosha, Sara; Mirhashemi, Fatemeh Sadat

2013-01-01

41

Combined Tooth-Implant-Supported Telescopic Prostheses in a Midterm Follow-up of > 2 Years.  

PubMed

Purpose: The aim of this trial was to evaluate telescopic-retained prostheses on teeth and implants. Materials and Methods: Ten patients with a mean of 2.8 teeth received strategic implants to achieve triangular/quadrangular support. Survival and complication rates were estimated for telescopic abutments and prostheses. Results: After a mean observation period of > 2 years, no abutment was lost and all prostheses were in function. Complication rates were low, and maintenance services were limited to minor interventions. Conclusions: Combined tooth-implant-retained telescopic prostheses improve prosthetic support and offer successful function over a midterm period in patients with a severely reduced dentition. PMID:24179966

Joda, Tim

42

AllCeram crowns for single replacement implant abutments.  

PubMed

Clinicians who are comfortable with traditional porcelain fused to metal restorations may find the thickness of veneering porcelain addition to the CeraOne single tooth ceramic cap disconcerting. When using a premanufactured ceramic cap to fit the space of the final restoration, substantial amounts of "unsupported" veneer porcelain may be required to achieve tooth contact to adjacent or opposing dentition. A potential problem of weak, unsupported veneer porcelain has been addressed by a modification of an existing manufacturing process. By using CAD/CAM technology, a custom-designed Procera AllCeram coping can be created for the implant abutment that eliminates any concerns regarding the resultant design of the underlying ceramic cap substructure. PMID:9399191

Razzoog, M E; Lang, L A; McAndrew, K S

1997-11-01

43

Retrospective and clinical evaluation of retrievable, tooth-implant supported zirconia-ceramic restorations.  

PubMed

Abstract Objective. Permanent cementations of zirconia-ceramic restorations may conflict with the rationale for retrievability of implant-supported restorations. The aim of this study was to test the hypothesis that retrievable, tooth-implant supported FDPs made of veneered zirconia ceramic cores are a viable treatment alternative. Material and methods. Restorations of patients in private practice and dental clinic were evaluated by reviewing patient records retrospectively and performing a final clinical examination. Permanently cemented copings protected the tooth abutments. The zirconia-ceramic restorations were semi-permanently cemented to the copings and the implant abutments using acrylic-urethane cement. In addition to Kaplan-Meier analyses for complications, the effect of age, gender, signs of bruxism, jaw and number of units on complications was estimated using Cox regression analyses (significance p < 0.05). Results. The follow-up period for 23 patients (nine with signs of bruxism) with four anterior and 27 posterior zirconia-ceramic restorations (3-12 units) ranged from 12.7-47.9 months. Core fractures of two posterior prostheses in patients with signs of bruxism yielded a 40-month survival rate of 93.5%. There were 10 cohesive chippings within the veneering porcelain for seven patients (six patients with signs of bruxism), which resulted in 40-month chipping rates of 5.6% among non-bruxers and 100% among patients with signs of bruxism. The hazard ratio for signs of bruxism was 20 (95% confidence interval: 2.1-188.3, p = 0.009). Conclusions. Retrievable, tooth-implant supported restorations made of zirconia-ceramics should be used with caution because of some core fractures and a considerable number of minor veneer fractures. The fracture risk was very high among patients with signs of bruxism. Due to the low number of occasions for intentional retrievals, a recommendation to use semi-permanently cemented, all-ceramic FDPs would still be premature. PMID:23394206

Mundt, Torsten; Heinemann, Friedhelm; Schankath, Christof; Schwahn, Christian; Biffar, Reiner

2013-02-11

44

Effect of an antirotation resistance form on screw loosening for single implant-supported crowns  

Microsoft Academic Search

Statement of problem: The gold screw of the single tooth implant-supported restoration has frequently been reported to exhibit the problem of screw loosening. Purpose: This in vitro study considered an antirotation resistance form with an increased moment arm length as a strategy to increase the net effect of the retaining screw preload. Material and methods: Three groups examined included (a)

Hoda Aboyoussef; Saul Weiner; David Ehrenberg

2000-01-01

45

Multicenter Retrospective Analysis of Wide-Neck Dental Implants for Single Molar Replacement  

Microsoft Academic Search

Purpose: To evaluate the predictability of Straumann wide-neck dental implants (6.5-mm prosthetic neck with a 4.8-mm endosseous sandblasted, large-grit, acid-etched-surface body) used for molar replacement. Materials and Methods: Four hundred ninety-nine single-tooth implants were restored in molar sites in 410 patients (mean time of loading 23 months; range, 1 to 54 months) by 6 clinicians throughout the United States. Three

Robert A. Levine; Jeffrey Ganeles; Robert A. Jaffin; Donald S. Clem; Jay R. Beagle; G. William Keller

46

[Clinical and histopathological observation of CaO-P2O5-MgO-SiO2-CaF system glass ceramic tooth implants in monkeys].  

PubMed

The present study was undertaken to determine the biocompatibility of a newly-developed CaO-P2O5-MgO-SiO2-CaF system glass ceramic tooth implant. Two adult male monkeys were selected and 12 weeks after extraction of M1 and P1, 8 glass ceramic teeth were implanted into alveolar bone. At 1 week after implantation, 6 teeth were allowed occlusal function, and 2 teeth were left free from occlusion as control teeth. The implants were observed for 4-12 weeks and examined histopathologically. The results were as follows: 1. Seven implanted teeth were well maintained clinically, and only one tooth was lost after 5 weeks. 2. In histopathological observation, implanted teeth were surrounded by bone, and connected by bonyankylosis. At cervix of dental implant, connective tissue as also attached firmly to implanted tooth surfaces and epithelial attachment was observed. 3. Although these implants were allowed occlusal function at an early stage (1 week after implantation), osteogenesis around implants was not disturbed. These results suggest that the new glass ceramic implant has good biocompatibility and is useful as an implant tooth. PMID:2562273

Hongo, O; Mukainakano, Y; Asano, M; Kawanami, M; Kato, H

1989-12-01

47

Quantum computer developement with single ion implantation  

SciTech Connect

Spins of single donor atoms are attractive candidates forlarge scale quantum information processing in silicon. Formation ofdevices with a few qubits is crucial for validation of basic ideas anddevelopment of a scalable architecture. We describe our development of asingle ion implantation technique for placement of single atoms intodevice structures. Collimated highly charged ion beams are aligned with ascanning probe microscope. Enhanced secondary electron emission due tohigh ion charge states (e.g., 31P13+, or 126Te33+) allows efficientdetection of single ion impacts. Studies of electrical activation of lowdose, low energy implants of 31P in silicon show a drastic effect ofdopant segregation to the SiO2/Si interface, while Si3N4/Si retards 31Psegregation. We discuss resolution limiting factors in ion placement, andprocess challenges for integration of single atom arrays with controlgates and single electron transistors.

Persaud, A.; Park, S.J.; Liddle, J.A.; Rangelow, I.W.; Bokor, J.; Keller, R.; Allen, F.I.; Schneider, D.H.; Schenkel, T.

2004-04-09

48

AllCeram crowns for single replacement implant abutments  

Microsoft Academic Search

Clinicians who are comfortable with traditional porcelain fused to metal restorations may find the thickness of veneering porcelain addition to the CeraOne single tooth ceramic cap disconcerting. When using a premanufactured ceramic cap to fit the space of the final restoration, substantial amounts of “unsupported” veneer porcelain may be required to achieve tooth contact to adjacent or opposing dentition. A

Michael E. Razzoog; Lisa A. Lang; Karen S. McAndrew

1997-01-01

49

Retrievable, tooth-implant-supported, complete-arch fixed restorations in the maxilla: a 6-year retrospective study.  

PubMed

The aim of this retrospective study was to evaluate the survival rate of implants, abutment teeth, and suprastructures along with the management of the complications for complete-arch, semipermanent cemented tooth-implant-supported restorations in 44 maxillae. Permanent cemented copings protect the prepared teeth from caries. The metal-ceramic fixed dental prostheses (FDPs) were cemented onto copings and implant abutments using acryl-urethane cement. Data were assessed via patient records and a final clinical examination. Six years after cementation, no implant or restoration had failed. After the extraction of two teeth and placement of an additional implant, three restorations had to be subsequently changed (89% of restorations were unchanged after 6 years). The loss of retention without tooth intrusion occurred in two restorations. All 23 restoration removals for prosthetic aftercare were non-destructive. The results of this study indicate that complete-arch, semipermanently cemented FDP rigidly connecting the maxillary teeth and implants are a reliable treatment option. PMID:23089639

Mundt, Torsten; Heinemann, Friedhelm; Schwahn, Christian; Biffar, Reiner

2012-02-01

50

Comparison of immediate complete denture, tooth and implant-supported overdenture on vertical dimension and muscle activity  

PubMed Central

PURPOSE To compare the changes in the occlusal vertical dimension, activity of masseter muscles and biting force after insertion of immediate denture constructed with conventional, tooth-supported and Implant-supported immediate mandibular complete denture. MATERIALS AND METHODS Patients were selected and treatment was carried out with all the three different concepts i.e, immediate denture constructed with conventional (Group A), tooth-supported (Group B) and Implant-supported (Group C) immediate mandibular complete dentures. Parameters of evaluation and comparison were occlusal vertical dimension measured by radiograph (at three different time intervals), Masseter muscle electromyographic (EMG) measurement by EMG analysis (at three different positions of jaws) and bite force measured by force transducer (at two different time intervals). The obtained data were statistically analyzed by using ANOVA-F test at 5% level of significance. If the F test was significant, Least Significant Difference test was performed to test further significant differences between variables. RESULTS Comparison between mean differences in occlusal vertical dimension for tested groups showed that it was only statistically significant at 1 year after immediate dentures insertion. Comparison between mean differences in wavelet packet coefficients of the electromyographic signals of masseter muscles for tested groups was not significant at rest position, but significant at initial contact position and maximum voluntary clench position. Comparison between mean differences in maximum biting force for tested groups was not statistically significant at 5% level of significance. CONCLUSION Immediate complete overdentures whether tooth or implant supported prosthesis is recommended than totally mucosal supported prosthesis.

Shah, Farhan Khalid; Gebreel, Ashraf; Elshokouki, Ali hamed; Habib, Ahmed Ali

2012-01-01

51

restorative dentistryA single visit, multidisciplinary approach to the management of traumatic tooth crown fracture  

Microsoft Academic Search

An immediate restorative technique resolving the acute problem of traumatic tooth fracture with pulpal and periodontal involvement, in which the fragment(s) are re-alignable. Repositioning facilitated by a custom stent, using dentine\\/enamel bonding. A challenging, conservative and economically viable procedure within the compass of a single visit.

C P K Wadhwani

2000-01-01

52

Early Loading of Single-Piece Implant for Partially Edentulous Posterior Arch: A Prospective One-Year Case Report  

PubMed Central

Implant therapy is now well established, and there is an increasing need for shorter rehabilitation time. Original prerequisites of osseointegration have been reassessed to satisfy continuously increasing patient's expectation of reduced treatment time, improved esthetics, and increased comfort. Shorter healing time may be appropriate in some circumstances, and examples of early loading have been reported in animal and human studies. However, to date there are insufficient data to determine a universally acceptable opinion on early loading of implants for single-tooth replacement. This case report involves early loading, combined with construction of a restoration, inserted directly after 6 weeks of implant surgery and followup of one year.

Beldar, Amol; Bhongade, Manohar L.; Byakod, Girish; Buregoni, Chandrashekar

2013-01-01

53

Immediate loading of screw-retained all-ceramic crowns in immediate versus delayed single implant placement.  

PubMed

Purpose: The aim of this study was to evaluate and compare the outcomes of immediately loaded all-ceramic crown restorations supported by implants placed in both mature bone and immediate extraction sockets. Materials and Methods: Forty-three tapered, external hex implants were placed immediately after extraction or in healed bone in a convenience sample of 38 patients from two clinics, with 23 implants immediately placed after tooth extraction and 20 placed in mature bone. Thirty implants were located in the maxilla and 13 in the mandible. Each surgical implant placement was followed by the fabrication of a screw-retained all-ceramic crown (zirconia-toughened alumina cylinder and layered with porcelain) that was then put into immediate function. Each patient was recalled annually for clinical and radiographic assessments. Results: All implants were loaded immediately and all functioned successfully following a mean follow-up of 26 months. Significantly more bone loss was recorded around delayed implants compared with immediately placed ones. Smoking, platform switching, and jaw location did not influence peri-implant bone loss. Porcelain chipping was noted in the case of two crowns. Conclusion: The short-term outcome of prefabricated ceramic cylinders used to support a single screw-retained crown was regarded as successful. Immediate implant placement did not appear to increase the risk for implant failure and was accompanied by reduced peri-implant bone loss. PMID:23998144

Vandeweghe, Stefan; Nicolopoulos, Costa; Thevissen, Eric; Jimbo, Ryo; Wennerberg, Ann; De Bruyn, Hugo

54

CAD/CAM-based implant abutments.  

PubMed

This article presents two novel options for lithium-disilicate restorations supported by single-tooth implants. By using a Ti-Base connector, hybrid abutments and hybrid abutment crowns can be fabricated for different implant systems. The latter option in particular is an interesting new process that yields economical and esthetic restorations supported by single-tooth implants. Further studies are urgently needed to validate the usefulness of this system. PMID:23930575

Kurbad, A; Kurbad, S

2013-01-01

55

Papillae alterations around single-implant restorations in the anterior maxillae: thick versus thin mucosa  

PubMed Central

To evaluate the papilla alterations around single-implant restorations in the anterior maxillae after crown attachment and to study the influence of soft tissue thickness on the papilla fill alteration. According to the inclusion criteria, 32 patients subjected to implant-supported single-tooth restorations in anterior maxillae were included. The patients were assigned to two groups according to the mucosal thickness: (i) group 1, 1.5 mm?mucosal thickness?3 mm; and (ii) group 2, 3 mmsingle-implant restorations could improve significantly over time after 6-month restoration according to PFI assessment. The thicker mucosa before implant placement implied a more favorable esthetic outcome in papilla alteration.

Si, Mi-Si; Zhuang, Long-Fei; Huang, Xin; Gu, Ying-Xin; Chou, Chung-Hao; Lai, Hong-Chang

2012-01-01

56

Single and double-plane iridium-192 interstitial implants: Implantation guidelines and dosimetry  

Microsoft Academic Search

Computerized dosimetric studies of single- and double-plane iridium-192 (Ir-192) planar implants were performed. With respect to dose homogeneity, we found that the optimal source and ribbon separation for single-plane implants was 1.0 cm. For double-plane implants, the preferred ribbon and plane separation was 1.5 cm, maintaining a 1-cm separation for the sources. Using these separations, standard dose rate curves for

David K. Kwan; A. R. Kagan; A. J. Olch; P. Y. M. Chan; B. L. Hintz; M. Wollin

1983-01-01

57

Implant Survival after Preparation of the Implant Site Using a Single Bur: A Case Series.  

PubMed

BACKGROUND: Implant site preparation usually consists of several consecutive drilling steps, performed using different burs with increasing diameter. PURPOSE: The purpose of the present study was to report the clinical outcomes of edentulous patients that underwent implant treatment, in which a special bur that allows preparation of the implant site in a single drilling step was used. MATERIAL AND METHODS: One hundred forty-nine patients (79 males, 70 females, mean age 51.8?±?12.2 [SD] years, range 20-80 years) have been rehabilitated using different oral surgery procedures. A total of 350 implants were inserted (171 in the maxilla and 179 in the mandible). A barrier membrane was used for covering a total of 126 implants. Fifteen implants were placed by using the osteotome technique and 52 by using the lateral sinus lift procedure. Eighty-nine implants were placed in postextraction sockets. Thirty-six implants underwent immediate loading. Implant survival, peri-implant bone level change, and patients' satisfaction were the main variables assessed. RESULTS: No patient dropout occurred. The mean follow-up on a patient basis was 21.5?±?3.1 months (range 12-27 months). A total of seven implant failures were recorded in six patients, leading to a mean implant survival of 98.0% (96.0% on a patient basis). The mean peri-implant bone loss after 1 year was 0.58?±?0.44?mm (n?=?282). Apart from implant failures, no biological nor mechanical complications occurred. All patients demonstrated full satisfaction. CONCLUSIONS: The use of a single bur for implant site preparation allows the reduction of the time needed for the surgical procedure, without compromising the clinical outcomes. Further, long-term comparative studies are needed to confirm the results of this study. PMID:23659356

Bettach, Raphaèl; Taschieri, Silvio; Boukhris, Gilles; Del Fabbro, Massimo

2013-05-01

58

Fabricating a nonrotational angulated abutment for a single-tooth prosthesis.  

PubMed

The fabrication of a custom waxed and cast nonrotational angulated abutment will be described. Most manufacturers of implant components fabricate angulated abutments for multiunit retrievable prostheses. However, they do not manufacture any components for a single unit that is screw retained. This article covers a step-by-step technique that was developed in an attempt to resolve this problem. PMID:20009602

Reid, Patrick E; Zinner, Ira D; Bhagat, Deepak

2009-12-01

59

Implant treatment choice after extraction of a vertically fractured tooth. A proposal for a clinical classification of bony defects based on a systematic review of literature.  

PubMed

OBJECTIVES: The objectives of this study were to propose a classification for the bone defects resulting after extraction of a vertically fractured tooth and to review the existing literature about the treatment of such kind of defects by means of dental implants in combination with regenerative procedures. MATERIALS AND METHODS: An electronic search was performed on biomedical databases using a combination of appropriated search terms combined through the use of Boolean operators. All articles concerning the treatment of peri-implant bone dehiscences and fenestrations through guided bone regeneration (GBR) with at least 6 months follow-up were eligible. Outcomes data extracted from the selected articles were summarized using descriptive tables. A classification of the bone defects associated with vertical root fracture (VRF) was also proposed. RESULTS: A total of 33 articles were included in the review. Twenty-three articles (814 implants) were about bone dehiscence treatment, ten articles presented the treatment of fenestrations, and ten (429 implants) adopted vertical bone augmentation. The percentage of bone filling was variable among different procedures and defect classification. The use of resorbable membrane was associated with better outcomes than the use of non-resorbable ones. CONCLUSIONS: Guided bone regeneration for the management of bone defects in the presence of a VRF of the extracted tooth is a viable treatment option. The assessment of bone defect geometry prior to a tooth extraction could be clinically relevant for evaluating the feasibility and the success of immediate implant placement as well as the need of GBR. PMID:23560723

Corbella, Stefano; Taschieri, Silvio; Samaranayake, Lakshman; Tsesis, Igor; Nemcovsky, Carlos; Del Fabbro, Massimo

2013-04-01

60

The effect of systemically administered bisphosphonates on bony healing after tooth extraction and osseointegration of dental implants in the rabbit maxilla.  

PubMed

Purpose: To evaluate the effects of bisphosphonates on bone healing after tooth extraction and osseointegration of dental implants in a rabbit model. Materials and Methods: Twenty-four rabbits were divided into four groups; one control and three experimental. The experimental were treated with intravenous zoledronic acid (ZA, 0.1 mg/kg) twice per week starting 4 (Z4 group) and 8 (Z8 group) weeks before surgery until the end of the experiments. The experimental ZD4 group was treated with intravenous ZA (0.01 mg/kg) and intramuscular dexamethasone (1 mg/kg) twice per week starting 4 weeks before surgery until the end of the experiments. The maxillary first premolar was extracted, and an implant with a diameter of 1.5 mm was placed between the incisor and the premolar of each maxilla. Healing of the extraction socket was evaluated and histomorphometric analysis around the implant was performed, using the bone-to-implant contact ratio (BIC) and bone area ratio (BA) 4 and 8 weeks after the surgery. Results: The control group underwent a normal healing process, but all experimental groups showed necrotic bone with hollow lacunae. BIC and BA in the control group increased from the 4- to 8-week evaluations, but decreased in the experimental groups from 4 to 8 weeks. BIC and BA of the Z8 and ZD4 groups were higher than those of the control group at the 4-week evaluation, but were lower than the control at the the 8-week evaluation. Conclusions: This study showed that administration of bisphosphonates interferes with normal bone remodeling after tooth extraction. The experimental groups showed good initial stability, but long-term healing around the implants was impaired. Within the limits of this study, it may be suggested that patients taking bisphosphonates should be treated with caution when performing tooth extraction or placing dental implants. PMID:24066308

Kim, Insoo; Ki, Hyungchun; Lee, Won; Kim, Heesung; Park, Jun-Beom

61

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

62

Single ion implantation for solid state quantum computer development  

SciTech Connect

Several solid state quantum computer schemes are based on the manipulation of electron and nuclear spins of single donor atoms in a solid matrix. The fabrication of qubit arrays requires the placement of individual atoms with nanometer precision and high efficiency. In this article we describe first results from low dose, low energy implantations and our development of a low energy (<10 keV), single ion implantation scheme for {sup 31}P{sup q+} ions. When {sup 31}P{sup q+} ions impinge on a wafer surface, their potential energy (9.3 keV for P{sup 15+}) is released, and about 20 secondary electrons are emitted. The emission of multiple secondary electrons allows detection of each ion impact with 100% efficiency. The beam spot on target is controlled by beam focusing and collimation. Exactly one ion is implanted into a selected area avoiding a Poissonian distribution of implanted ions.

Schenkel, Thomas; Meijers, Jan; Persaud, Arun; McDonald, Joseph W.; Holder, Joseph P.; Schneider, Dieter H.

2001-12-18

63

Physics of Heavily Implanted Single Crystal Complex Oxides  

NASA Astrophysics Data System (ADS)

Ion implantation is known to result in a significant amount of damage in solid single crystals. In this work a battery of material probes is used to study the effect of a very high-dose He implantation in ferroelectric lithium niobate (LiNbO3) and the implantation-induced formation of defects. In addition, the evolution of these defects with post-implantation annealing is examined. After irradiation, a high concentration of defects is found to collect and create a network of thick prismatic planar defects having typical dimensions of ˜1.5 microm and 200 nm parallel and perpendicular to the Z axis, respectively. Optical microscopy shows that there is strong temperature dependence for forming the network; the density of these defects reaches a maximum value for an annealing temperature of 250 °C. However, annealing to temperatures above 380 °C fully eliminates the defects. High-resolution TEM studies indicate that the defects are likely localized twinning and dislocation pileups due to plastic deformation of the lattice to relieve He-implantation-induced stress. During this deformation He accumulates at the twin boundaries. A second type of implantation induced defects is studied using room temperature, high- resolution electron microscopy; this study shows that implanted He in LiNbO3 nucleates and accumulates as bubbles. These He inclusions are at ˜20 GPa pressure and most probably in the solid phase. In addition, the energetically favored shape of the inclusions in their as-implanted form is spherical and not oblate; this spherical shape is due to the fact their diameter is below a critical radius for balancing the surface and elastics energies as predicted by elastic theory. When annealed, the characteristic length scale of the He inclusions increases, forming faceted bubbles. Annealing also causes the He inclusions to migrate and accumulate into strings due to the preferred {1014}-pyramidal-twinning planes. The ion implantation-induced defects are found to be useful for several microfabrication techniques, in particular we describe the use of these defects for ion slicing of single crystal thin films from bulk crystals and ferroelectric domain patterning by low voltage pulses applied to a scanning force microscope tip. The origin of the rate of anomalously high spatially selective etching of a buried heavily implanted region in complex oxides is found to be closely related to the implantation-induced defects. He+-ion implantation in single-crystal LiNbO3 samples followed by low-temperature anneal and wet etched results in an etch-rate enhancement of 104. This high rate selective etch is crucial for the Crystal Ion Slicing process, a novel technique to fabricate single crystal thin films by slicing them off a bulk crystal. Experiments, using time-resolved optical microscopy and proximal-probe microscopy, show that this enhancement arises from the more rapid etch-solution transport in the thick prismatic planar defect network formed in the implanted region after annealing. Ferroelectric domain patterns are generated in He-implanted single-crystal bulk wafers of LiNbO3 by means of low-voltage pulses applied to a scanning force microscope tip and investigated using piezoresponse force microscopy and selective etching. It is shown that high fluence implantation results in isolation of the near surface region, creating a free-standing-film-like behavior for the layer above the heavily implanted region. At low fluence the implantation damage allows low voltage poling, apparently by vacancy-induced dipole formation. In addition, electrostatic repulsion of the poling-induced buried charges from adjacent domains limits the domain size and depth; this effect results in a uniform domain structures and potentially enables large area nanodomains patterns to be written.

Ofan, Avishai

64

A study of single crystal zirconia implanted with platinum ions  

NASA Astrophysics Data System (ADS)

Single crystal samples of (100) oriented cubic (yttria stabilized zirconia)(YSZ) were implanted with 105 and 160 keV platinum ions, using a metal vapor vacuum are (MEVVA) high current ion implanter, to nominal doses of 2 × 1016 ions/cm2 and 5 × 1016 ions/cm2, respectively, at room temperature (RT). The implanted samples were annealed isothermally in air ambient at 850°C and 1100°C from 4 to 12 h. Rutherford Backscattering Spectrometry and Channeling: (RBS-C of 2 MeV He ions has been used to study the depth distribution of lattice damage and implant, is well as the annealing behavior. X-ray diffraction (XRD) is employed to analyze the crystallite of implanted platinum. Both as-implanted samples do not show an amorphous phase. The Pt depth profile was almost unchanged for all samples during annealing at 850°C and 1100°C. For the 160 keV implantes sample no loss of Pt was observed after annealing at 1100°C. XRD results provide evidence for the formation of a monoclinic phase of ZrO2 in the damage region after 1100°C annealing. For all annealed samples, Pt (2 0 0) preferred orientation crystallites were observed by XRD, while the Pt (111) peak was almost not visible for 850°C annealed samples.

Xie, D.-Z.; Zhu, D.-Z.; Cao, D.-X.; Zhou, Z.-Y.

1997-11-01

65

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.

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

2013-01-01

66

Optimization of single keV ion implantation for the construction of single P-donor devices  

Microsoft Academic Search

We report recent progress in single keV ion implantation and online detection for the controlled implantation of single donors in silicon. When integrated with silicon nanofabrication technology this forms the \\

Changyi Yang; David N. Jamieson; Toby Hopf; Soren E. Andresen; Sean M. Hearne; Fay E. Hudson; Christopher I. Pakes; Mladen Mitic; Eric Gauja; Grigori Tamanyan; Andrew S. Dzurak; Steven Prawer; Robert G. Clark

2005-01-01

67

Methods and compositions for culturing a biological tooth  

US Patent & Trademark Office Database

Tooth tissues include the pulp mesenchyme that forms the dentin and an epithelium that is responsible for enamel formation. Cells from these tissues were obtained from porcine third molars and were seeded onto a biodegradable scaffold composed of a polyglycolic acid--polylactic acid copolymer. Cell polymer constructs were then surgically implanted into the omentum of athymic nude rats so that the constructs would have a blood supply and these tissues were allowed to develop inside the rats. Infrequently, columnar epithelial cells were observed as a single layer on the outside of the dentin-like matrix similar to the actual arrangement of ameloblasts over dentin during early tooth development. Developing tooth tissues derived from such cell polymer constructs could eventually be surgically implanted into the gum of an edentulous recipient where the construct would receive a blood supply and develop to maturity, providing the recipient with a biological tooth replacement.

Yelick; Pamela C. (Concord, MA); Bartlett; John D. (Acton, MA); Vacanti; Joseph P. (Winchester, MA); Olsen; Bjorn R. (Milton, MA); Stashenko; Phillip (Medfield, MA)

2005-05-31

68

Single chip CMOS image sensors for a retina implant system  

Microsoft Academic Search

This work describes the architecture and realization of microelectronic components for a retina implant system that will provide visual sensations to patients with photoreceptor degeneration by applying electrostimulation of the intact retinal ganglion cell layer. Special circuitry has been developed for a fast single-chip CMOS image sensor system which provides high dynamic range of more than seven decades (without a

M. Schwarz; R. Hauschild; B. J. Hosticka; J. Huppertz; T. Kneip; S. Kolnsberg; W. Mokwa; H. K. Trieu

1998-01-01

69

Single sideband encoder for music coding in cochlear implants  

Microsoft Academic Search

The restoration of melody perception is a key remaining challenge in cochlear implants. We propose a new sound coding strategy that converts an audio signal into time-varying electrically stimulating pulse trains. A sound is first split into several frequency subbands and each subband signal is coherently downward shifted to a low-frequency base band, similar to demodulation used in single sideband

Kaibao Nie; Les E. Atlas; Jay Rubinstein

2008-01-01

70

Single word and sentence intelligibility in children with cochlear implants.  

PubMed

This study examined the intelligibility of speech produced by 17 children (aged 4-11 years) with cochlear implants. Stimulus items included sentences from the Beginners' Intelligibility Test (BIT) and words from the Children Speech Intelligibility Measure (CSIM). Naïve listeners responded by writing sentences heard or with two types of responses to the word recordings; open transcription (CSIM-T) and closed set multiple choice (CSIM-MC). Percentage of items understood, averaged across three naïve judges, were compared across the three measures. Additionally, scores were examined for any relationships with chronological age, age of implantation, and amount of implant experience. Strong positive correlations were observed among all three intelligibility tasks. Scores on all three tasks were found to be significantly different from each other. A significant correlation was obtained between intelligibility and amount of implant experience, but not with chronological age or age of implantation. Results suggest that judging the intelligibility of speech produced by children with cochlear implants using both single word and sentence levels would provide a better overall estimate of their intelligibility. The results also emphasize the vital role of auditory input in the development of intelligible speech. PMID:20645856

Khwaileh, Fadwa A; Flipsen, Peter

2010-09-01

71

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

Microsoft Academic Search

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

Ben Balevi; Sasha Shepperd

2007-01-01

72

[Dental students' opinions on education in fabricating single-tooth fixed prostheses and multi-teeth fixed prostheses].  

PubMed

Education in fabricating single-tooth fixed prostheses and multi-teeth fixed prostheses is an important component of the dental curriculum. To explore the opinion of dental students on this component of the curriculum, a web-based survey was carried out among the students of the 3 dental schools in the Netherlands. The 389 completed questionnaires revealed that the education in fabricating single-tooth fixed prostheses and multi-teeth fixed prostheses started in different years of study at the 3 dental schools. Another striking difference is that the methods of preparation and the choice of materials for single-tooth fixed prostheses and multi-teeth fixed prostheses in the pre-clinical practicum in the programmes was not the same. The students of the 3 dental schools seemed to have a reasonably positive opinion of their preclinical training preparation for treating patients. The opinions of the Nijmegen Dental School students were significantly more positive than the opinions of the students at the 2 other dental schools. PMID:23373308

Brand, H S; Kharbanda, A; Kamell, H; Dozic, A

2012-12-01

73

Optima XE Single Wafer High Energy Ion Implanter  

SciTech Connect

The Optima XE is the first production worthy single wafer high energy implanter. The new system combines a state-of-art single wafer endstation capable of throughputs in excess of 400 wafers/hour with a production-proven RF linear accelerator technology. Axcelis has been evolving and refining RF Linac technology since the introduction of the NV1000 in 1986. The Optima XE provides production worthy beam currents up to energies of 1.2 MeV for P{sup +}, 2.9 MeV for P{sup ++}, and 1.5 MeV for B{sup +}. Energies as low as 10 keV and tilt angles as high as 45 degrees are also available., allowing the implanter to be used for a wide variety of traditional medium current implants to ensure high equipment utilization. The single wafer endstation provides precise implant angle control across wafer and wafer to wafer. In addition, Optima XE's unique dose control system allows compensation of photoresist outgassing effects without relying on traditional pressure-based methods. We describe the specific features, angle control and dosimetry of the Optima XE and their applications in addressing the ever-tightening demands for more precise process controls and higher productivity.

Satoh, Shu; Ferrara, Joseph; Bell, Edward; Patel, Shital; Sieradzki, Manny [Axcelis Technologies, Inc. 108 Cherry Hill Drive, Beverly, MA 01915 (United States)

2008-11-03

74

A single-channel implantable microstimulator for functional neuromuscular stimulation  

Microsoft Academic Search

The single-channel implantable microstimulator device measures 2×2×10 mm 3 and can be inserted into paralyzed muscle groups by expulsion from a hypodermic needle. Power and data to the device are supplied from outside by RF telemetry using an amplitude-modulated 2-MHz RF carrier generated using a high-efficiency class-E transmitter. The transmitted signal carries a 5-b address which selects one of the

Babak Ziaie; Mark D. Nardin; Anthony R. Coghlan; Khalil Najafi

1997-01-01

75

Process Performance of Optima XEx Single Wafer High Energy Implanter  

SciTech Connect

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. [Axcelis Technologies, 108 Cherry Hill Drive, Beverly, MA 01950 (United States); Jang, I. S.; Cha, J. C.; Joo, Y. H.; Lee, A. B.; Jin, S. W. [Hynix Semiconductor Inc., San 136-1 Ami, Bubal, Ichon, Kyoungki-do, 467-701 (Korea, Republic of)

2011-01-07

76

Nanofabrication of charge-based Si:P quantum computer devices using single-ion implantation  

Microsoft Academic Search

We report on progress towards a charge-based qubit using phosphorus atoms implanted in a silicon substrate. Prototype devices have been fabricated using standard lithographic techniques together with a new method of controlled single ion implantation using on-chip detector electrodes. Positional accuracy of the implanted ions was achieved using a nanoaperture mask defined using electron beam lithography. The two implanted phosphorus

Mladen Mitic; Soren E. Andresen; Victor C. Chan; Tilo M. Buehler; Andrew J. Ferguson; Eric Gauja; Fay E. Hudson; David J. Reilly; A. R. Hamilton; Andrew S. Dzurak; Robert G. Clark; Changyi Yang; Toby Hopf; Christopher I. Pakes; David N. Jamieson

2005-01-01

77

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.

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

2011-01-01

78

Impacted tooth  

MedlinePLUS

... tooth that fails to fully pass through the gums. ... Teeth start to pass through the gums (emerge) during infancy, and again when the primary (baby) teeth are replaced by the permanent teeth. If a tooth fails to emerge, ...

79

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

2013-07-01

80

Integration of an Axcelis Optima HD Single Wafer High Current Implanter for p- and n-S/D Implants in an Existing Batch Implanter Production Line  

SciTech Connect

This paper is focused on the integration and qualification of an Axcelis Optima HD single wafer high current spot beam implanter in an existing 200 mm production line with different types of Axcelis batch implanters for high current applications. Both the design of the beamline and the beam shape are comparable between single wafer and batch high current spot beam implanters. In contrast to the single wafer high current ribbon beam implanter, energy contamination is not a concern for the considered spot beam tool because the drift mode can be used down to energies in the 2 keV region. The most important difference between single wafer and batch high current implanters is the significantly higher dose rate and, therefore, the higher damage rate for the single wafer tool due to the different scanning architecture. The results of the integration of high dose implantations, mainly for p- and n-S/D formation, for DRAM 110 nm without pre-amorphization implantation (PAI), CMOS Logic from around 250 nm down to 90 nm without and with PAI, are presented and discussed. Dopant concentration profile analysis using SIMS was performed for different technologies and implantation conditions. The impurity activation was measured using sheet resistance and in some cases spreading resistance technique was applied. The amorphous layer thickness was measured using TEM. Finally, device data are presented in combination with dose, energy and beam current variations. The results have shown that the integration of implantation processes into crystalline structure without PAI is more complex and time consuming than implantations into amorphous layer where the damage difference due to the different dose rates is negligible.

Schmeide, Matthias [Infineon Technologies Dresden GmbH and Co. OHG, Koenigsbruecker Str. 180, D-01099 Dresden (Germany); Kontratenko, Serguei; Krimbacher, Bernhard [Axcelis Technologies, Inc., 108 Cherry Hill Dr., Beverly, MA (United States); Mueller, Ralf Peter [Qimonda Dresden GmbH and Co. OHG, Koenigsbruecker Str. 180, D-01099 Dresden (Germany)

2008-11-03

81

Optimized single pulse stimulation strategy for retinal implants  

NASA Astrophysics Data System (ADS)

Retinal implants offer prospects of vision restoration for some blind patients by eliciting visual percepts of spots of light called ‘phosphenes’. Recently, a mathematical model has been developed that predicts patients' perception of phosphene brightness for current-driven electrical stimulation of the retina. This model is explored for different stimulation parameters on a single electrode, including safety and hardware limitations, to produce phosphenes of specified brightness. We describe a procedure to derive stimulation parameters to account for such constraints, and describe methods to construct optimal stimuli in terms of producing maximal perceived brightness and efficient generation of phosphenes of a given brightness by employing minimal energy. In both cases, it is found that the resulting optimized stimulation waveforms consist of a long stimulation period, and interphase delays between initial and charge-balancing phases.

Savage, C. O.; Grayden, D. B.; Meffin, H.; Burkitt, A. N.

2013-02-01

82

Immediate or Early Placement of Implants Following Tooth Extraction: Review of Biologic Basis, Clinical Procedures, and Outcomes  

Microsoft Academic Search

Purpose: The aim of this article was to review the current literature with regard to survival and success rates, along with the clinical procedures and outcomes associated with immediate and delayed implant placement. Materials and Methods: A MEDLINE search was conducted of studies published between 1990 and June 2003. Randomized and nonrandomized clinical trials, cohort studies, case- control studies, and

Stephen T. Chen; Thomas G. Wilson Jr; Christoph H. F. Hämmerle

83

Accurate Dose Control with Pressure Compensation System on Single-Wafer Ion Implanters  

SciTech Connect

On ion implanters, dosimetry is generally controlled by monitoring an electrical current detected with Faraday cup(s) instead of the actual number of dopants. In some cases, ions in a beam undergo charge exchange phenomenon, interacting with residual gas molecules in a beamline. This charge exchange of ions causes variations of the detected beam currents which result in inaccurate dosimetry of implanted dopants. We will introduce to you a system similar to Pressure Compensation of the batch-type ion implanters to single-wafer ion implanters, that is, the SHX high current ion implanter and the MC3-II medium current ion implanter. The system converts the beam current detected with Faraday cups to an adequate value for dose control as a function of beamline pressure and brings accurate dosimetry also in these single-wafer ion implanters.

Sano, Makoto; Yamada, Tatsuya; Sato, Fumiaki; Tsukihara, Mitsukuni; Sugitani, Michiro [SEN Corporation, an SHI and Axcelis Company 1501 Imazaike, Saijo, Ehime, 799-1362 (Japan)

2008-11-03

84

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.

Khetarpal, Ambica; Talwar, Sangeeta; Verma, Mahesh

2013-01-01

85

Dental Implants  

MedlinePLUS

Dental Implants Did you know that dental implants are frequently the best treatment option for replacing missing teeth? ... implants can last a lifetime. Anatomy of a Dental Implant A dental implant designed to replace a single ...

86

Molecular strategies for pre-implantation genetic diagnosis of single gene and chromosomal disorders.  

PubMed

Pre-implantation genetic diagnosis is used to analyse pre-implantation stage embryos or oocytes for genetic defects, generally for severe Mendelian disorders and chromosome abnormalities. New but controversial indications for pre-implantation genetic diagnosis include identifying human leukocyte antigen compatible embryos suitable as donor, sex selection and adult-onset disorders, particularly cancer. Pre-implantation genetic screening is a variant of pre-implantation genetic diagnosis to improve outcomes of in-vitro fertilisation. Array comparative genomic hybridisation is replacing fluorescence in-situ hybridisation for aneuploidy screening. Besides technical advancement of array platform, the success of pre-implantation genetic screening is strongly related to the embryonic biological nature of chromosomal mosaicism. Having been applied for more than 20 years, pre-implantation genetic diagnosis is recognised as an important alternative to prenatal diagnosis. Diagnosis from a single cell, however, remains a technically challenging procedure, and the risk of misdiagnosis cannot be eliminated. PMID:22858134

Jiang, Boran; Tan, Arnold S C; Chong, Samuel S

2012-08-01

87

Introduction of the SHX-III System, a Single-Wafer High-Current Ion Implanter  

Microsoft Academic Search

The SHX-III system, categorized as a single-wafer high-current ion implanter, has been developed by SEN Corporation in order to meet all the requirements for high dose and relatively high mid-dose applications, including high-tilted multi-step implantation. Recently the three major advanced device types, namely logic devices, memory and imagers, started to require high-current ion implanters in diverse ways. The SHX-III is

Michiro Sugitani; Mitsukuni Tsukihara; Mitsuaki Kabasawa; Koji Ishikawa; Hiroki Murooka; Kazuyoshi Ueno

2008-01-01

88

Genes affecting tooth morphogenesis.  

PubMed

The development of dentition is a fascinating process that encompasses a complex series of epithelial-mesenchymal interactions involving growth factors, transcription factors, signal receptors and other soluble morphogens. It is not surprising that such a complex process is prone to disturbances and may result in tooth agenesis. Initial discoveries indicating that the homeo-domain protein MSX1 and the paired-domain transcription factor PAX9 are causative genes in tooth morphogenesis were made in mice. Both genes are co-expressed in dental mesenchyme and either one, when homozygously deleted, results in an arrest at an early developmental stage. Previous studies have shown a down regulation of Bmp4 gene expression in Pax9 and Msx1 single mutant mice. Therefore, we chose to explore the molecular relationship between Pax9, Msx1 and Bmp4. In humans, unlike in mice, a heterozygous mutation in either PAX9 or MSX1 suffices to cause tooth agenesis of a predominantly molar or more premolar pattern, respectively. Our laboratory and others have identified several PAX9 and MSX1 mutations in families with non-syndromic forms of autosomal dominant posterior tooth agenesis. We have also identified families with tooth agenesis in whom PAX9 and MSX1 mutations have been excluded opening up the possibilities for the discovery of other genes that contribute to human tooth agenesis. PMID:17973693

Kapadia, H; Mues, G; D'Souza, R

2007-11-01

89

Optical and magnetic properties of nitrogen ion implanted MgO single crystal  

NASA Astrophysics Data System (ADS)

The microstructure, optical property and magnetism of nitrogen ion implanted single MgO crystals are studied. A parallel investigation is also performed in an iron ion implanted single MgO sample as a reference. Large structural, optical and magnetic differences are obtained between the nitrogen and iron implanted samples. Room temperature ferromagnetism with a fairly large coercivity field of 300 Oe (1 Oe=79.5775 A/m), a remanence of 38% and a slightly changed optical absorption is obtained in the sample implanted using nitrogen with a dose of 1×1018 ions/cm2. Transition metal contamination and defects induced magnetism can be excluded when compared with those of the iron ion implanted sample, and the nitrogen doping is considered to be the main origin of ferromagnetism.

Liu, Chun-Ming; Gu, Hai-Quan; Xiang, Xia; Zhang, Yan; Jiang, Yong; Chen, Meng; Zu, Xiao-Tao

2011-04-01

90

Photoluminescence from single nitrogen isoelectronic centers in gallium phosphide produced by ion implantation  

NASA Astrophysics Data System (ADS)

Single emitters formed from two nitrogen isoelectronic traps in GaP are created by low energy implantation. Several dyad configurations are individually resolved, establishing that ion implantation can produce multi-impurity single emitters with high luminescence yield. Measured dyad concentrations significantly exceed those predicted from simulations, suggesting that their formation is strongly enhanced by implantation defects. Annealing at 600 °C optimizes the luminescence yield and higher temperatures lead to the physical dissociation of dyads. The dissociation activation energy increases with interatomic separation, indicating that nearest neighbor dyads are energetically unfavorable and that their concentration can be adjusted with a simple temperature treatment.

Éthier-Majcher, G.; St-Jean, P.; Bergeron, A.; Phaneuf-L'Heureux, A.-L.; Roorda, S.; Francoeur, S.

2013-07-01

91

Tooth Decay  

MedlinePLUS

... cavity. Your dentist calls it tooth decay or dental caries. They're all names for a hole ... or abscess. To help prevent cavities Brush your teeth every day with a fluoride toothpaste Clean between ...

92

Characterization of Charging Control of a Single Wafer High Current Spot Beam Implanter  

SciTech Connect

This paper focuses on the characterization of charging control of an Axcelis Optima HD single wafer high current spot beam implanter using MOS capacitors with attached antennas of different size and shape. Resist patterns are implemented on Infineon Technologies own charging control wafers to investigate the influence of photo resist on charging damage. Compared to batch high current implanters the design of the beamline and the beam shape are comparable to single wafer high current spot beam implanters, however due to the different scanning architecture the dose rate of the single wafer high current spot beam implanters is significantly higher compared to the batch tools. Therefore, the risk of charging damage will be higher. The charging damage was studied as a function of the energy, the beam current and the most important plasma flood gun parameters. The results have shown that for very high antenna ratios the charging damage for single wafer implanters, even spot or ribbon beam implanters, is higher than for high current batch implanters.

Schmeide, Matthias; Bukethal, Christoph [Infineon Technologies Dresden GmbH and Co. OHG, Koenigsbruecker Str. 180, D-01099 Dresden (Germany)

2008-11-03

93

Characterization of Charging Control of a Single Wafer High Current Spot Beam Implanter  

NASA Astrophysics Data System (ADS)

This paper focuses on the characterization of charging control of an Axcelis Optima HD single wafer high current spot beam implanter using MOS capacitors with attached antennas of different size and shape. Resist patterns are implemented on Infineon Technologies own charging control wafers to investigate the influence of photo resist on charging damage. Compared to batch high current implanters the design of the beamline and the beam shape are comparable to single wafer high current spot beam implanters, however due to the different scanning architecture the dose rate of the single wafer high current spot beam implanters is significantly higher compared to the batch tools. Therefore, the risk of charging damage will be higher. The charging damage was studied as a function of the energy, the beam current and the most important plasma flood gun parameters. The results have shown that for very high antenna ratios the charging damage for single wafer implanters, even spot or ribbon beam implanters, is higher than for high current batch implanters.

Schmeide, Matthias; Bukethal, Christoph

2008-11-01

94

Thermal behaviour of helium-implanted spinel single crystals  

NASA Astrophysics Data System (ADS)

The study of the microstructural modifications induced in spinel implanted with 4He+ at 4.7 at.% and subsequently annealed at 1075 K is addressed in this paper. The combination of three analysis techniques Rutherford backscattering spectrometry in channeling geometry (RBS/C), X-ray diffraction and transmission electron microscopy was used in order to gain information about the damage depth distribution, the nature of radiation defects, and the occurrence of microstructural modifications. In as-implanted crystals the disorder level is weak, and the damage principally consists of small helium-vacancy clusters. These defects induce a tensile strain in the direction normal to the implanted crystal surface. After annealing, a surprising increase of the disorder level is measured by RBS/C. This increased backscattering yield is due to the formation of a particular type of He-vacancy clusters, namely He platelets, which also induce a relaxation of the strain.

Velisa, G.; Debelle, A.; Vincent, L.; Thomé, L.; Declémy, A.; Pantelica, D.; Antohe, S.

2011-09-01

95

Fabrication of single atom nanoscale devices by ion implantation  

Microsoft Academic Search

Fabrication of nanoscale devices that exploit the rules of quantum mechanics to process information presents a formidable technical challenge because it will be necessary to control quantum states at the level of individual atoms, electrons or photons. We have developed a pathway to the construction of quantum devices using ion implantation and demonstrate, using charge transport analysis, that the devices

D. N. Jamieson; V. Chan; F. E. Hudson; S. E. Andresen; C. Yang; T. Hopf; C. I. Pakes; S. Rubanov; S. M. Hearne; S. Prawer; E. Gauja; A. S. Dzurak; R. G. Clark

2006-01-01

96

Local lattice distortions in single Co-implanted ZnO nanowires  

NASA Astrophysics Data System (ADS)

This work reports on the local structure of as-implanted and thermally-treated single Co:ZnO nanowires studied using a hard X-ray nanoprobe. Although the Co ions are incorporated into the wurtzite ZnO lattice, X-ray absorption near edge structure data show high structural disorder in the as-implanted nanowires compared with the annealed ones. In particular, extended X-ray absorption fine structure from single wires reveals a lattice distortion around Zn sites of the as-implanted nanowires, which involves an expansion of the stable wurtzite lattice. The observed local lattice response confirms good recovery of the implantation-induced damage within the ZnO lattice through a thermal treatment.

Chu, M. H.; Martínez-Criado, G.; Segura-Ruiz, J.; Geburt, S.; Ronning, C.

2013-09-01

97

Integration of Single Ion Implantation Method in Focused Ion Beam System for Nanofabrication  

Microsoft Academic Search

A method of single ion implantation based on the online detection of individual ion impacts on a pure silicon substrate has been implemented in a focused ion beam (FIB) system. The optimized silicon detector integrated with a state-of-art low noise electronic system and operated at a low temperature makes it possible to achieve single ion detection with a minimum energy

Changyi Yang; David N. Jamieson; Sean Hearne; Toby Hopf; Chris Pakes; S teven Prawer; Søren E. Andresen; Andrew Dzurak; E. Gauja; F. E. Hudson; R. G. Clark

2006-01-01

98

Charge-based silicon quantum computer architectures using controlled single-ion implantation  

Microsoft Academic Search

We report a nanofabrication, control and measurement scheme for charge-based silicon quantum computing which utilises a new technique of controlled single ion implantation. Each qubit consists of two phosphorus dopant atoms ~50 nm apart, one of which is singly ionized. The lowest two energy states of the remaining electron form the logical states. Surface electrodes control the qubit using voltage

A. S. Dzurak; L. C. L. Hollenberg; D. N. Jamieson; F. E. Stanley; C. Yang; T. M. Buhler; V. Chan; D. J. Reilly; C. Wellard; A. R. Hamilton; C. I. Pakes; A. G. Ferguson; E. Gauja; S. Prawer; G. J. Milburn; R. G. Clark

2003-01-01

99

Stability of ion implanted single-walled carbon nanotubes: Thermogravimetric and Raman analysis  

Microsoft Academic Search

In this work, the effect of different ions (hydrogen, helium, and neon) implanted on single-walled carbon nanotube (SWNT) is being analyzed using thermogravimetric analysis (TGA), Raman scattering, and x-ray photoelectron spectroscopy (XPS). The TGA result shows that the temperature for maximum decomposition rate (Tmax) increases at relatively low doses, i.e., by about 30 °C after hydrogen ion implantation (at the

Ananta R. Adhikari; Mengbing Huang; Hassaram Bakhru; Robert Vajtai; Chang Y. Ryu; Pulickel M. Ajayan

2006-01-01

100

Place-pitch discrimination of single- versus dual-electrode stimuli by cochlear implant users  

Microsoft Academic Search

Simultaneous or near-simultaneous activation of adjacent cochlear implant electrodes can produce pitch percepts intermediate to those produced by each electrode separately, thereby increasing the number of place-pitch steps available to cochlear implant listeners. To estimate how many distinct pitches could be generated with simultaneous dual-electrode stimulation, the present study measured place-pitch discrimination thresholds for single- versus dual-electrode stimuli in users

Gail S. Donaldson; Heather A. Kreft; Leonid Litvak

2005-01-01

101

Mesenchymal stem cells and tooth engineering.  

PubMed

Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSCs for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth (SHEDs), adult dental pulp stem cells (DPSCs), stem cells from the apical part of the papilla (SCAPs), stem cells from the dental follicle (DFSCs), periodontal ligament stem cells (PDLSCs) and bone marrow derived mesenchymal stem cells (BMSCs). This review outlines the recent progress in the mesenchymal stem cells used in tooth regeneration. PMID:20690498

Peng, Li; Ye, Ling; Zhou, Xue-dong

2009-03-01

102

An in situ annealing study of lead implanted single crystal calcium titanate  

NASA Astrophysics Data System (ADS)

In situ annealing studies have been carried out in ion-implanted single crystals of CaTiO3. These crystals were implanted along both the a and b axes of this orthorhombic perovskite structure (Pcmn). Through the use of a Panasonic video cassette recorder connected to a Gatan television system on a JEOL 200CX transmission electron microscope, the regrowth process was observed and the growth rate monitored. Samples were annealed in a Gatan single tilt hot stage at ~ 475° C. The near-surface region of this material, approximately 190 nm, is turned amorphous by the implantation of 540 keV Pb ions at a fluence of 1 × 1015/cm2. Annealing at 475° C results in the epitaxial regrowth of the damaged region. The regrowth process begins at the original amorphous/crystalline interface and proceeds outward to the surface. This phenomenon has been studied for implantations along both the <010> and the <100> crystallographic directions. For constant accelerating voltage and fluence of the implanted lead ions, transmission electron microscopy (TEM) and Rutherford backscattering spectroscopy (RBS) [C.W. White et al., to be published in Proc. of Radiation Effects in Insulators, Lyon, France, 1987.] indicate that the regrowth rate is linear with time but strongly dependent on the oxygen partial pressure in the annealing atmosphere, and the implantation and subsequent regrowth direction.

Rankin, J.; Hobbs, L. W.; Boatner, L. A.; White, C. W.

1988-05-01

103

3D-FEA of osseointegration percentages and patterns on implant-bone interfacial stresses  

Microsoft Academic Search

Objectives: The degree of osseointegration and its patterns are important for the success of implants. 3D-FEA was used to determine interfacial stresses on a single tooth implant (IMZ) for four degrees of osseointegration (100, 75, 50 and 25%), and five patterns at 50% osseointegration (locally alternating, coronal only, apical only, facial only and lingual only).Methods: The implant was restored with

G. Papavasiliou; P. Kamposiora; S. C. Bayne; D. A. Felton

1997-01-01

104

Single-chip CMOS image sensors for a retina implant system  

Microsoft Academic Search

This work describes the architecture and realization of microelectronic components for a retina-implant system that will provide visual sensations to patients suffering from photoreceptor degeneration. Special circuitry has been developed for a fast single-chip CMOS image sensor system, which provides high dynamic range of more than seven decades (without any electronic or mechanical shutter) corresponding to the performance of the

Markus Schwarz; Ralf Hauschild; Bedrich J. Hosticka; J. Huppertz; T. Kneip; S. Kolnsberg; L. Ewe; Hoc Khiem Trieu

1999-01-01

105

Simulation of Phosphorus Implantation into Silicon with a Single Parameter Electronic Stopping Power Model  

Microsoft Academic Search

We simulate dopant profiles for phosphorus implantation into silicon using a new model for electronic stopping power. In this model, the electronic stopping power is factorized into a globally averaged effective charge Z1*, and a local charge density dependent electronic stopping power for a proton. There is only a single adjustable parameter in the model, namely the one electron radius

David Cai; Charles M. Snell; Keith M. Beardmore; Niels Grønbech-Jensen

1998-01-01

106

Regeneration Electrode Units: Implants for Recording from Single Peripheral Nerve Fibers in Freely Moving Animals  

Microsoft Academic Search

Implantable electrode assemblies that become penetrated by regenerating axons were used to record signals from single sensory and motor nerve fibers associated with leg movement in unrestrained amphibians (Xenopus laevis). Such neuroimplants may provide a means for establishing the roles of various muscle afferents and efferents in posture and locomotion, and have potential clinical applications.

Allan Mannard; Richard B. Stein; Dean Charles

1974-01-01

107

Introduction of the SHX-III System, a Single-Wafer High-Current Ion Implanter  

NASA Astrophysics Data System (ADS)

The SHX-III system, categorized as a single-wafer high-current ion implanter, has been developed by SEN Corporation in order to meet all the requirements for high dose and relatively high mid-dose applications, including high-tilted multi-step implantation. Recently the three major advanced device types, namely logic devices, memory and imagers, started to require high-current ion implanters in diverse ways. The SHX-III is designed to fulfill such a variety of requirements in one system. The SHX-III has the same end station as the MC3-II/WR, SEN's latest medium current implanter, which has a mechanical throughput of 450 WPH. This capability and precise dose control system of the SHX-III causes dramatic productivity enhancement for application of mid-high dose, ranged between 5E13 to 2E14 atoms/cm2, usually performed by medium current ion implanters. In this paper the concept and performance of the SHX-III will be described, concerning influence of device characteristics. A concept and performance data of the SHX figure that this system can provide implant quality and productivity as far as the 32 nm node.

Sugitani, Michiro; Tsukihara, Mitsukuni; Kabasawa, Mitsuaki; Ishikawa, Koji; Murooka, Hiroki; Ueno, Kazuyoshi

2008-11-01

108

Introduction of the SHX-III System, a Single-Wafer High-Current Ion Implanter  

SciTech Connect

The SHX-III system, categorized as a single-wafer high-current ion implanter, has been developed by SEN Corporation in order to meet all the requirements for high dose and relatively high mid-dose applications, including high-tilted multi-step implantation. Recently the three major advanced device types, namely logic devices, memory and imagers, started to require high-current ion implanters in diverse ways. The SHX-III is designed to fulfill such a variety of requirements in one system. The SHX-III has the same end station as the MC3-II/WR, SEN's latest medium current implanter, which has a mechanical throughput of 450 WPH. This capability and precise dose control system of the SHX-III causes dramatic productivity enhancement for application of mid-high dose, ranged between 5E13 to 2E14 atoms/cm2, usually performed by medium current ion implanters. In this paper the concept and performance of the SHX-III will be described, concerning influence of device characteristics. A concept and performance data of the SHX figure that this system can provide implant quality and productivity as far as the 32 nm node.

Sugitani, Michiro; Tsukihara, Mitsukuni; Kabasawa, Mitsuaki; Ishikawa, Koji; Murooka, Hiroki; Ueno, Kazuyoshi [SEN Corporation, an SHI and Axcelis Company 1501 Imazaike, SaiJo, Ehime, 799-1362 (Japan)

2008-11-03

109

Origins of low resistivity in Al ion-implanted ZnO bulk single crystals  

NASA Astrophysics Data System (ADS)

The origins of low resistivity in Al ion-implanted ZnO bulk single crystals are studied by combining Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA), photoluminescence (PL), and Van der Pauw methods. The Al-ion implantation (peak concentration: 2.6 × 1020cm-3) into ZnO is performed using a multiple-step energy. The resistivity decreases from ~104 ? cm for un-implanted ZnO to 1.4 × 10-1 ? cm for as-implanted, and reaches 6.0 × 10-4 ? cm for samples annealed at 1000 °C. RBS and NRA measurements for as-implanted ZnO suggest the existence of the lattice displacement of Zn (Zni) and O (Oi), respectively. After annealing at 1000 °C, the Zni related defects remain and the Oi related defects disappear. The origin of the low resistivity in the as-implanted sample is attributed to the Zni (~30 meV [Look et al., Phys. Rev. Lett. 82, 2552 (1999)]). In contrast, the origin of the low resistivity in the sample annealed at 1000 °C is assigned to both of the Zni related defects and the electrically activated Al donor. A new PL emission appears at around 3.32 eV after annealing at 1000 °C, suggesting electrically activated Al donors.

Oga, T.; Izawa, Y.; Kuriyama, K.; Kushida, K.; Kinomura, A.

2011-06-01

110

Immediate implantation with provisionalization: from literature to clinical implications.  

PubMed

Numerous studies have confirmed the predictability of dental implants used for the replacement of a single missing tooth. Successful application of this surgical protocol is still technique sensitive and should be executed only by experienced restorative teams. Factors such as implant stability, implant design, immediate loading, provisionalization, and various others have a direct influence on the result of this procedure. This article reviews current literature on immediate implant placement and provides clinical guidelines aimed at improving the use of this technique in daily restorative practice. PMID:12593295

Touati, Bernard; Guez, Gerard

111

Initial experience with off-pump left ventricular assist device implantation in single center: retrospective analysis  

PubMed Central

Background We hypothesize that implantation of left ventricular assist device through off-pump technique is feasible and has a comparable result to implantation on cardiopulmonary bypass and could improve one-year survival. Methods This retrospective, observational, single-center study was conducted on 29 consecutive patients at our institution who underwent off-pump left ventricular assist device implantation by a single surgeon. Results Twenty-seven procedures were performed successfully using the off-pump technique. The survival rate was 92% at 30 days, 76% at 90 days, and 67% at one year. We compared the one-year survival of different implantation periods, and divided our study into three time intervals (2004-2005, 2006, and 2007). There was a trend in reduction in number of deaths over one year that demonstrated a decrease in death rate from 50% to 17%, as well as improvement in our experience over time. However, this trend is not statistically significant (p = 0.08) due to limited sample size. Conclusions Based upon our findings, off-pump left ventricular assist device implantation is a feasible surgical technique, and combining this technique with improved device technology in the future may provide even greater improvement in patient outcomes.

2010-01-01

112

Investigation of avalanche silicon detectors for low energy single ion implantation applications  

Microsoft Academic Search

Avalanche silicon photodiodes have potential applications to detect low energy single ions for counting single ion impacts in shallow implant depths for the deterministic doping of nanoscale electronic devices. This paper reports the investigation of avalanche photodiode detectors in the linear operation mode for detection of 0.5–2MeV helium ions. The measured charge gain was found to be up to 100

Changyi Yang; David Jamieson

2010-01-01

113

Posterior tooth replacement with dental implants in sites augmented with rhBMP-2 at time of extraction--a case series.  

PubMed

This case series demonstrates seven molar-site implants placed in six consecutively treated patients. All sites were augmented with rhBMP-2 (1.50 mg/cc)/ACS (recombinant human Bone Morphogenetic Protein-2/Absorbable Collagen Sponge) at extraction to regenerate bone-facilitating implant placement. In four patients, osteotomies were initiated with trephines to evaluate qualitatively for native bone and for the absence of residual ACS. All sites facilitated implant placement after augmentation. All seven implants achieved primary stabilization and were functionally loaded. No implants were lost or developed complications. It can be concluded that augmenting molar extraction sockets with rhBMP-2/ACS can allow standard implant placement in the posterior dentition that is capable of withstanding a functional load. PMID:22545428

Levin, Barry P; Tawil, Peter

2012-02-01

114

Implantation  

Microsoft Academic Search

\\u000a This chapter describes required facilities, preoperative procedures, anesthesia, and operative techniques for the implantation\\u000a of currently available defibrillator models. Electrophysiologists would prefer not to have to think about the days when defibrillator\\u000a implantations were performed using a median sternotomy with mortality rates exceeding five percent. The size reduction of\\u000a the generators and the use of transvenous leads have allowed subcutaneous

Antonio Pacifico; Philip D. Henry

115

The effectiveness of a single osteointegrated implant combined with pendulum springs for molar distalization.  

PubMed

The aim of this report was to present the clinical efficiency of a single osteointegrated implant combined with pendulum springs for molar distalization. A 15-year-old girl sought treatment for irregular anterior teeth and poor smile esthetics. A novel appliance was designed that combined osteointegrated implants with 0.032-in beta-titanium wire and pendulum springs. The treatment results were evaluated from lateral cephalometric radiographs. Distalization of the maxillary first molars was achieved in 6 months. Total treatment time was 21 months. Facial esthetics improved as a consequence of treatment. This appliance design offers reliable molar distalization, even when absolute anchorage is required. PMID:17276871

Onca?, Gökhan; Akyalçin, Sercan; Arikan, Fatih

2007-02-01

116

The effect of flash lamp annealing on Fe implanted ZnO single crystals  

SciTech Connect

The effect of flash lamp annealing applied to ZnO single crystals implanted with 3.6 at. % Fe has been studied. For intermediate light power, the implantation-induced surface defects could be annealed without creation of secondary phases within the implanted region. At the same annealing temperatures, however, ion-beam-induced open volume defects start to increase in size. Recrystallization is initiated for the highest light power applied, i.e., the ion-beam-induced lattice disorder reflected by the minimum channeling yield of Rutherford backscattering spectroscopy decreases from 76% to 46% and the open volume defects are annealed. At the same time, the Fe{sup 3+} fraction increases at the cost of the Fe{sup 2+} states. Weak ferromagnetic properties that are mainly associated with nanoparticles are induced.

Potzger, K.; Anwand, W.; Reuther, H.; Zhou, Shengqiang; Talut, G.; Brauer, G.; Skorupa, W.; Fassbender, J. [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)

2007-02-01

117

Stability of ion implanted single-walled carbon nanotubes: Thermogravimetric and Raman analysis  

SciTech Connect

In this work, the effect of different ions (hydrogen, helium, and neon) implanted on single-walled carbon nanotube (SWNT) is being analyzed using thermogravimetric analysis (TGA), Raman scattering, and x-ray photoelectron spectroscopy (XPS). The TGA result shows that the temperature for maximum decomposition rate (T{sub max}) increases at relatively low doses, i.e., by about 30 deg. C after hydrogen ion implantation (at the ion dose of 10{sup 15} cm{sup -2}), 17 deg. C after helium ion implantation (at the ion dose of 10{sup 13} cm{sup -2}), and contributes no significant enhancement after neon implantation for all doses. The increase of T{sub max} indicates that small mass ion can be utilized to improve the thermal-oxidative stability of SWNTs. Raman scattering and XPS were used to monitor the lattice damage from ion implantation and chemical bonding states of the materials. The results indicated the material rigidity for low doses of hydrogen and helium, while the application of higher doses of neon caused the material to transform towards amorphous carbon (a-C)

Adhikari, Ananta R.; Huang Mengbing; Bakhru, Hassaram; Vajtai, Robert; Ryu, Chang Y.; Ajayan, Pulickel M. [College of Nanoscale Science and Engineering, State University of New York, Albany, New York 12203 (United States); Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Department of Material Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 and Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2006-09-15

118

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.

Garcia-Elias, Elena; Gil-Garay, Enrique

2007-01-01

119

Single-crystal diamond plate liftoff achieved by ion implantation and subsequent annealing  

SciTech Connect

We describe a new method for removing thin, large area sheets of diamond from bulk or homoepitaxial diamond crystals. This method consists of an ion implantation step, followed by a selective etching procedure. High energy (4--5 MeV) implantation of carbon or oxygen ions creates a well-defined layer of damaged diamond that is buried at a controlled depth below the surface. For C implantations, this layer is graphitized by annealing in vacuum, and then etched in either an acid solution, or by heating at 550--600 [degree]C in oxygen. This process successfully lifts off the diamond plate above the graphite layer. For O implantations of a suitable dose (3[times]10[sup 17] cm[sup [minus]2] or greater), the liftoff is achieved by annealing in vacuum or flowing oxygen. In this case, the O required for etching of the graphitic layer is also supplied internally by the implantation. This liftoff method, combined with well-established homoepitaxial growth processes, has considerable potential for the fabrication of large area single crystalline diamond sheets.

Parikh, N.R.; Hunn, J.D.; McGucken, E.; Swanson, M.L. (University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States)); White, C.W. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6048 (United States)); Rudder, R.A.; Malta, D.P.; Posthill, J.B.; Markunas, R.J. (Research Triangle Institute, Research Triangle Park, North Carolina 27709-2194 (United States))

1992-12-28

120

Single-tooth replacement in the esthetic zone with ridge expansion osteotomy: a clinical report and radiographic results.  

PubMed

Maxillary alveolar atrophy often limits the placement of dental implants. The bone splitting and bone widening by osteotome technique is a more obvious method for the immediate placement of implants in those cases in which the dimensions of the residual ridge are reduced by only a small degree. Few studies have been performed that are aimed at the radiographic results shown after the osteotome technique by a low-dose computed tomography scan and assessment of objective improvement of the bone density using Misch's classification. The aim of this clinical case was to analyze the radiographic data of the osteotome technique on the change of bone density and to demonstrate efficacy of the ridge expansion crest to bypass bone fenestrations of the buccal plate in the esthetic zone. The advantages of this technique for patients include less surgical trauma and a shorter treatment time. PMID:18780567

Santagata, Mario; Guariniello, Luigi; D'Andrea, Alfredo; Tartaro, Gianpaolo P

2008-01-01

121

Surface modification of single crystal silicon by Ar + ion implantation and vacuum deposition of amorphous carbon coating  

Microsoft Academic Search

Single crystal silicon wafers (Si (100) ) were implanted with 110 keV Ar+ ions at a fluence of 1×1016 ions\\/cm2. Then the unimplanted and ion-implanted Si surfaces were coated with an amorphous carbon coating of 50±5 nm thick making use of vacuum vapor deposition. The microstructures of the unimplanted and Ar+ ion implanted Si wafers were analysed by means of

Rong Sun; Tao Xu; Qun-ji Xue

2006-01-01

122

Simulation of phosphorus implantation into silicon with a single-parameter electronic stopping power model  

Microsoft Academic Search

We simulate dopant profiles for phosphorus implantation into silicon using a\\u000anew model for electronic stopping power. In this model, the electronic stopping\\u000apower is factorized into a globally averaged effective charge Z1*, and a local\\u000acharge density dependent electronic stopping power for a proton. There is only\\u000aa single adjustable parameter in the model, namely the one electron radius

DAVID CAI; CHARLES M. SNELL; KEITH M. BEARDMORE; NIELS GRØNBECH-JENSEN

1999-01-01

123

On the annealing of damage produced by boron ion implantation of silicon single crystals  

Microsoft Academic Search

Using the techniques of Rutherford scattering, electron microscopy and infra-red absorption, the damage produced by implantation of 100 to 400 keV boron (B) ions in silicon single crystals, held at room and liquid nitrogen temperatures, has been examined, and the annealing behaviour investigated. The rapid annealing of disorder in the range between room temperature and 325°C, as observed by the

L. T. Chadderton; F. H. Eisen

1971-01-01

124

Magnetic nano-particles of Ni in MgO single crystals by ion implantation  

Microsoft Academic Search

Magnetic Ni nano-particles in the near surface regions of MgO single crystals have been synthesized by 64keV Ni ion implantation to 1×1017cm?2 followed by thermal annealing. Transmission electron microscopy (TEM) and magnetic properties measurement system (MPMS) equipped with a superconducting quantum interference device (SQUID) detector have been employed to characterize the microstructure and magnetic properties of the Ni nano-particles. The

S. Zhu; X. Xiang; X. T. Zu; L. M. Wang

2006-01-01

125

Magnetic nano-particles of Ni in MgO single crystals by ion implantation  

Microsoft Academic Search

Magnetic Ni nano-particles in the near surface regions of MgO single crystals have been synthesized by 64 keV Ni ion implantation to 1 × 1017 cm-2 followed by thermal annealing. Transmission electron microscopy (TEM) and magnetic properties measurement system (MPMS) equipped with a superconducting quantum interference device (SQUID) detector have been employed to characterize the microstructure and magnetic properties of

S. Zhu; X. Xiang; X. T. Zu; L. M. Wang

2006-01-01

126

Origins of low resistivity in Al ion-implanted ZnO bulk single crystals  

SciTech Connect

The origins of low resistivity in Al ion-implanted ZnO bulk single crystals are studied by combining Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA), photoluminescence (PL), and Van der Pauw methods. The Al-ion implantation (peak concentration: 2.6 x 10{sup 20}cm{sup -3}) into ZnO is performed using a multiple-step energy. The resistivity decreases from {approx}10{sup 4{Omega}} cm for un-implanted ZnO to 1.4 x 10{sup -1{Omega}} cm for as-implanted, and reaches 6.0 x 10{sup -4{Omega}} cm for samples annealed at 1000 deg. C. RBS and NRA measurements for as-implanted ZnO suggest the existence of the lattice displacement of Zn (Zn{sub i}) and O (O{sub i}), respectively. After annealing at 1000 deg. C, the Zn{sub i} related defects remain and the O{sub i} related defects disappear. The origin of the low resistivity in the as-implanted sample is attributed to the Zn{sub i} ({approx}30 meV [Look et al., Phys. Rev. Lett. 82, 2552 (1999)]). In contrast, the origin of the low resistivity in the sample annealed at 1000 deg. C is assigned to both of the Zn{sub i} related defects and the electrically activated Al donor. A new PL emission appears at around 3.32 eV after annealing at 1000 deg. C, suggesting electrically activated Al donors.

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); Kinomura, A. [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

2011-06-15

127

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

128

Tooth Agenesis: from Molecular Genetics to Molecular Dentistry  

Microsoft Academic Search

Tooth agenesis may originate from either genetic or environmental factors. Genetically determined hypodontic disorders appear as isolated features or as part of a syndrome. Msx1, Pax9, and Axin2 are involved in non-syndromic hypodontia, while genes such as Shh, Pitx2, Irf6, and p63 are considered to participate in syndromic genetic disorders, which include tooth agenesis. In dentistry, artificial tooth implants represent

E. Matalova; J. Fleischmannova; P. T. Sharpe; A. S. Tucker

2008-01-01

129

Sonosurgery for atraumatic tooth extraction: a clinical report.  

PubMed

The preservation of an intact labial plate during tooth extraction is a critical determinant of whether an immediate implant can be placed and is also an important predictor of the esthetic result. The purpose of this clinical report was to present a method for atraumatic tooth extraction by using an air-driven sonic instrument with specially designed inserts. This surgical technique provides the clinician with an efficient method for atraumatic tooth extraction and preservation of an intact labial plate. PMID:23217465

Papadimitriou, Dimitrios E V; Geminiani, Alessandro; Zahavi, Thomas; Ercoli, Carlo

2012-12-01

130

[Tooth regeneration in the guinea pig (Cavia porcellus)].  

PubMed

The first inferior molar has been extracted, a part of its being reimplanted or not. A new molar of normal form regenerated, apparently from the apex of the tooth germ, in all cases in which the alveolus was left free or implanted with a tooth freagment deprived of pulpa. PMID:145296

Stephan, F; Artis, J P; Lanot, R

1977-01-01

131

Effect of Ar + ion implantation on the nano-mechanical properties and microstructure of single crystal silicon  

Microsoft Academic Search

The effect of argon ion implantation on the nano-machanical properties of single crystal Si was examined making use of nano-indentation and nano-scratch tests. The morphologies of the scratched tracks of the unimplanted Si and that implanted at a moderate Ar+ fluence were observed on a scanning electron microscope, while the changes in the microstructure of the single crystal Si by

Rong Sun; Tao Xu; Qun-Ji Xue

2005-01-01

132

Deep level transient spectroscopic study of oxygen implanted melt grown ZnO single crystal  

NASA Astrophysics Data System (ADS)

Deep level traps in melt grown ZnO single crystal created by oxygen implantation and subsequent annealing in air were studied by deep level transient spectroscopy measurement between 80 and 300 K. The EC-0.29 eV trap (E3) was the dominant peak in the as-grown sample and no new defects were created in the as-O-implanted sample. The single peak feature of the deep level transient spectroscopy (DLTS) spectra did not change with the annealing temperature up to 750 °C, but the activation energy decreased to 0.22 eV. This was explained in terms of a thermally induced defect having a peak close to but inseparable from the original 0.29 eV peak. A systematic study on a wide range of the rate window for the DLTS measurement successfully separated the Arrhenius plot data originated from different traps. It was inferred that the E3 concentration in the samples did not change after the O-implantation. The traps at EC-0.11, EC-0.16 and EC-0.58 eV were created after annealing. The EC-0.16 eV trap was assigned to an intrinsic defect. No DLTS signal was found after the sample was annealed to 1200 °C.

Ye, Z. R.; Lu, X. H.; Ding, G. W.; Fung, S.; Ling, C. C.; Brauer, G.; Anwand, W.

2011-09-01

133

Open questions in electronic sputtering of solids by slow highly charged ions with respect to applications in single ion implantation  

SciTech Connect

In this article we discuss open questions in electronic sputtering of solids by slow, highly charged ions in the context of their application in a single ion implantation scheme. High yields of secondary electrons emitted when highly charged dopant ions impinge on silicon wafers allow for formation of non-Poissonian implant structures such as single atom arrays. Control of high spatial resolution and implant alignment require the use of nanometer scale apertures. We discuss electronic sputtering issues on mask lifetimes, and damage to silicon wafers.

Schenkel, T.; Rangelow, I.W.; Keller, R.; Park, S.J.; Nilsson, J.; Persaud, A.; Radmilivitc, V.R.; Liddle, J.A.; Grabiec, P.; Bokor, J.; Schneider, D.H.

2003-07-16

134

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

135

Tissue Engineering of Complex Tooth Structures on Biodegradable Polymer Scaffolds  

Microsoft Academic Search

Tooth loss due to periodontal disease, dental caries, trauma, or a variety of genetic disorders continues to affect most adults adversely at some time in their lives. A biological tooth substitute that could replace lost teeth would provide a vital alternative to currently available clinical treatments. To pursue this goal, we dissociated porcine third molar tooth buds into single-cell suspensions

C. S. Young; S. Terada; J. P. Vacanti; M. Honda; J. D. Bartlett; P. C. Yelick

2002-01-01

136

Esthetic soft tissue ridge augmentation around dental implant: Case report  

PubMed Central

The aim of this case report is to present a method to correct soft tissue ridge deformity around dental implant using acellular dermal matrix (ADM). A 25-year-old female patient presented with a missing maxillary first left premolar, which had class I soft tissue defect. The missing tooth was replaced with single implant supported prosthesis and the soft tissue defect was corrected using ADM utilizing the envelop technique. A 5-years follow-up is presented showing the long-term stability of this technique and the predictability of using the ADM as an alternative method to connective tissue graft to correct the soft tissue defect around dental implant.

Al-Hamdan, Khalid S.

2011-01-01

137

Crown-to-implant ratios of short-length implants.  

PubMed

Excessive crown-implant ratios have been cited in the literature as being detrimental to long-term implant survival. However, unfavorable crown-implant ratios have not yet been established. The primary aim of this study was to determine the crown-implant ratios of single-tooth implant-supported restorations on short-length implants in a clinical practice, and to evaluate the health of these implants via mesial and distal first bone-to-implant contact levels. Additionally, the relationship between crown-implant ratios and proximal first bone-to-implant contact levels will be evaluated. In this retrospective cohort study, the cohort was composed of 194 patients who possessed at least 1 single 5.7 mm or 6 mm length plateau design implant-supported restoration that had been surgically placed between February 1997 and December 2005. A chart review was performed to acquire the most recent radiographs in which both the entire crown and the implant were visible. The length of the crown and implant was measured directly from the radiographs using consistent magnification to calculate the crown-implant ratio. Mesial and distal first bone-to-implant contact levels were measured using 3 times magnification and were mathematically corrected for distortion. The last available radiograph was used to measure bone levels. Follow-up time was calculated from the day of implant placement to the date of the last available radiograph. Statistical analyses with analysis of variance mixed models were used. Data from 309 single implant-supported fixed restorations were tabulated and included in the study. The mean (SD) follow-up time was 20.9 (23.2) months, with a range of 15.6 to 122.8 months. The mean crown length (SD) was 13.4 (2.6) mm, with a range of 6.2 to 21.7 mm. The mean (SD) crown-implant ratio was 2.0 (0.4) and ranged from 0.9 to 3.2. The average mesial and distal first bone-to-implant contact levels (SD) measured from the radiographs were -0.2 (0.7) mm and -0.2 (0.9) mm, respectively. No statistically significant relationship was observed between increasing crown-implant ratios and decreasing mesial and distal first bone-to-implant contact levels around the implant with P values of .94 and .57, respectively. In this investigation, mesial and distal first bone-to-implant contact levels on short-length implants fall within the established guidelines for success. Also, there are no associations between crown-implant ratios and first bone-to-implant contact levels. PMID:20545533

Birdi, Hardeep; Schulte, John; Kovacs, Alejandro; Weed, Meghan; Chuang, Sung-Kiang

2010-06-14

138

Marginal bone loss influence on the biomechanics of single implant crowns.  

PubMed

Marginal bone loss, whether it is physiological or pathological, is one of the implant treatment complications. The biomechanical consequences of marginal bone loss could be catastrophic particularly when the abutment screw is at supraosseous level. This study aimed at investigating marginal bone loss influence on the biomechanics of single implant crown using finite element (FE) analysis. Four FE models for a 3.5 × 13 mm implant supported by 4 bone levels (8.5 mm, 10 mm, 11.5 mm, and 13 mm) were subjected to 3 loading conditions: vertical, oblique, and horizontal. The results indicated 5-10 times increase in maximum von Mises stresses under oblique and horizontal loading. The maximum stresses within the fixture were concentrated at the bone/fixture interface with highest value under horizontal loading at 10 mm bone support. Abutment screw was most susceptible to fracture as the highest stress was concentrated at the screw/fixture interface. Cortical bone suffered its greatest stress level at the fixture/bone interface at 10 mm bone support. However, increasing bone support to 11.5 mm has improved the fracture resistance of the abutment screw to a great extent especially under oblique and vertical loading. Severe marginal bone loss might be attributed for abutment screw and fixture head fracture especially under horizontal loading. PMID:23851832

Romeed, Shihab A; Malik, Raheel; Dunne, Stephen M

2013-07-01

139

Ferromagnetism in Mn-implanted ZnO:Sn single crystals  

Microsoft Academic Search

We have investigated the magnetic properties of Mn-implanted n-type ZnO single crystals that are codoped with Sn. Theory predicts that room-temperature carrier-mediated ferromagnetism should be possible in manganese-doped p-type ZnO, although Mn-doped n-type ZnO should not be ferromagnetic. While previous efforts report only low-temperature ferromagnetism in Mn-doped ZnO that is n type via shallow donors, we find evidence for ferromagnetism

D. P. Norton; S. J. Pearton; A. F. Hebard; N. Theodoropoulou; L. A. Boatner; R. G. Wilson

2003-01-01

140

Tooth formation - delayed or absent  

MedlinePLUS

Specific diseases can have a profound effect on tooth shape, tooth color, time of appearance, or tooth absence. Delayed or absent tooth formation can result from many different conditions, including: Apert syndrome Cleidocranial dysostosis ...

141

Tooth Colored Fillings  

MedlinePLUS

... enough healthy tooth left to fill, a restoration is created to replace most of the visible tooth, or to crown it. These are more involved procedures and cannot be made directly to the tooth and cannot be placed the same day .

142

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

NASA Astrophysics Data System (ADS)

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 Zn1-xFexO 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.

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

2013-10-01

143

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 Zn1-xFexO 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

2013-09-11

144

Nano hillock and complex crater formation by low-energy proton implantation with incident angle into lithium niobate single crystal  

Microsoft Academic Search

The formation of nano-size hillocks and simple and complex craters was observed as a result of ion–surface collisions with a lithium niobate single crystal on proton implantation. The low-energy ion implantation process is considered as a controllable and versatile tool for surface and near-surface modifications down to an atomic scale as an alternative to the swift heavy ion irradiation effect.

P. Kumar; S. Moorthy Babu

2011-01-01

145

Bacteremia Associated with Tooth Brushing and Dental Extraction  

PubMed Central

Background Antibiotic prophylaxis recommendations for the prevention of infective endocarditis are based in part on studies of bacteremia from dental procedures, but tooth brushing may pose a greater threat. The purpose of this study was to compare the incidence, duration, nature and magnitude of endocarditis-related bacteremia from single tooth extraction and tooth brushing, and to determine the impact of amoxicillin prophylaxis on single tooth extraction. Methods and Results In this double-blind, placebo-controlled study, 290 subjects were randomized to 1) tooth brushing, 2) single tooth extraction with amoxicillin prophylaxis, or 3) single tooth extraction with identical placebo. Blood was drawn for bacterial culturing and identification at six time points before, during and after these interventions. The focus of our analysis was on bacterial species reported to cause infective endocarditis. We identified 98 bacterial species, 32 of which are reported to cause endocarditis. Cumulative incidence of endocarditis-related bacteria from all 6 blood draws was 23%, 33% and 60% for the tooth brushing, extraction-amoxicillin and extraction-placebo groups, respectively (p<0.0001). Significant difference were identified among the three groups at draws 2, 3, 4 and 5 (all p<0.05). Amoxicillin resulted in a significant decrease in positive cultures (p<0.0001). Conclusions Although amoxicillin has a significant impact on bacteremia from a single tooth extraction, given the greater frequency for oral hygiene, tooth brushing may be a greater threat for individuals at risk for infective endocarditis.

Lockhart, Peter B.; Brennan, Michael T.; Sasser, Howell C.; Fox, Philip C.; Paster, Bruce J.; Bahrani-Mougeot, Farah K.

2009-01-01

146

Developmental stage on day-5 and fragmentation rate on day-3 can influence the implantation potential of top-quality blastocysts in IVF cycles with single embryo transfer  

Microsoft Academic Search

BACKGROUND: In IVF-ICSI cycles with single embryo transfer (SET), embryo selection for transfer is of crucial importance. The present study aimed to define which embryo parameters might be related to the implantation potential of advanced blastocysts. METHODS: Overall, in 203 cycles with SET, developmental characteristics of 93 implanted (group A) and 110 non-implanted (group B) advanced blastocysts of good quality

Tiziana della Ragione; Greta Verheyen; Evangelos G Papanikolaou; Lisbet Van Landuyt; Paul Devroey; Andre Van Steirteghem

2007-01-01

147

An Optically Powered Single-Channel Stimulation Implant as Test System for Chronic Biocompatibility and Biostability of Miniaturized Retinal Vision Prostheses  

Microsoft Academic Search

A microsystem based microimplant with an optically powered single-channel stimulator was designed and developed as test system for an epi-retinal vision implant. Biostability of the hybrid assembly and the encapsulation materials were evaluated in pilot experiments in chronic implantations in a cat animal model. The implant was fabricated on a flexible polyimide substrate with integrated platinum electrode, interconnection lines, and

Thomas Schanze; Lutz Hesse; Carsten Lau; Nina Greve; Werner Haberer; Sascha Kammer; Thomas Doerge; Andreas Rentzos; Thomas Stieglitz

2007-01-01

148

Implantation of a dual chamber pacing and sensing single pass defibrillation lead.  

PubMed

Dual-chamber ICDs are increasingly used to avoid inappropriate shocks due to supraventricular tachycardias. Additionally, many ICD patients will probably benefit from dual chamber pacing. The purpose of this pilot study was to evaluate the intraoperative performance and short-term follow-up of an innovative single pass right ventricular defibrillation lead capable of bipolar sensing and pacing in the right atrium and ventricle. Implantation of this single pass right ventricular defibrillation lead was successful in all 13 patients (age 63 +/- 8 years; LVEF 0.44 +/- 0.16; New York Heart Association [NYHA] 2.4 +/- 0.4, previous open heart surgery in all patients). The operation time was 79 +/- 29 minutes, the fluoroscopy time 4.7 +/- 3.1 minutes. No perioperative complications occurred. The intraoperative atrial sensing was 1.7 +/- 0.5 mV, the atrial pacing threshold product was 0.20 +/- 0.14 V/ms (range 0.03-0.50 V/ms). The defibrillation threshold was 8.8 +/- 2.7 J. At prehospital discharge and at 1-month and 3-month follow-up, atrial sensing was 1.9 +/- 0.9, 2.1 +/- 0.5, and 2.7 +/- 0.6 mV, respectively, (P = NS, P < 0.05, P < 0.05 to implant, respectively), the mean atrial threshold product 0.79, 1.65, and 1.29 V/ms, respectively. In two patients, an intermittent exit block occurred in different body postures. All spontaneous and induced ventricular arrhythmias were detected and terminated appropriately. Thus, in a highly selected patient group, atrial and ventricular sensing and pacing with a single lead is possible under consideration of an atrial pacing dysfunction in 17% of patients. PMID:11341077

Gradaus, R; Block, M; Dorszewski, A; Schriever, C; Hammel, D; Scheld, H H; Borggrefe, M; Breithardt, G; Böcker, D

2001-04-01

149

Clinical evaluation of short and wide-diameter implants immediately placed into extraction sockets of posterior areas: a 2-year retrospective study.  

PubMed

The objective of the study was to determine the short-term success rate of short and wide single-tooth implants, immediately placed into extraction sockets of the posterior area. A retrospective cohort study design was used. A total of 145 subjects received 162 short and wide-diameter single-tooth implants between 2006 and 2009. A minimal 7-mm residual height and 9-mm ridge width was available in all the implant sites, and the attached gingivae were at least 2 mm wide. All implants were placed and restored with the single crown by one experienced operator. The data were analyzed with descriptive statistics. All implants were placed in molar areas. There were 20 Ankylos implants with a diameter 5.5 or 7 mm and a length of 8 mm and 142 hydroxyapatite-coated implants with a diameter 5 or 6 mm and a length of 5.7 to 8 mm. One of the 162 implants failed before prosthetic restoration, resulting in a survival rate of 99.4% after loading. Patients were followed for up to 56 months (mean = 24 months) after loading of implants. The radiographic and clinical data revealed well-maintained hard and soft tissues with acceptable short-term results. For residual ridges with minimal height but adequate width, the immediate placement of short and wide-diameter implants in fresh extraction sockets may offer a simple and predictable treatment alternative if implants are positioned appropriately after a thorough preoperative analysis. PMID:23317299

Jiansheng, Huang; Dongying, Xuan; Xianfeng, Wang; Baoyi, Xie; Qiong, Liu; Jincai, Zhang

2012-12-01

150

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

NASA Astrophysics Data System (ADS)

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 350 ^oC , 650 ^oC and 750 ^oC. Three peaks were identified in the DLTS spectra of the 900 ^oC sample, with the activation energies of 0.11eV, 0.25eV and 0.37eV respectively. The thermal evolutions of the deep levels up to the temperature of 1200 ^oC were also investigated. [4pt] [1] Q. L. Gu, C. C. Ling, X. D. Chen, C. K. Cheng, A. M. C. Ng, C. D. Beling, S. Fung, A. B. Djurisi'c, L. W. Lu, G. Brauer and H. C. Ong, Appl. Phys. Lett. 90, 122101, (2007).

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

2011-03-01

151

Studio 'In vitro' Sulla Connessione di Sistemi Implantari Dentali ('In vitro' Study on Dental Implant System Connection).  

National Technical Information Service (NTIS)

In the last ten years a great development in dental implant technology research has been obtained in a way to become now a therapeutic solution not only for totally edentulism but also for one single-tooth edentulism. Aim of this work has been to evaluate...

F. Di Carlo F. Rizzo P. Loppolo R. Bedini R. Pecci

2007-01-01

152

Micromachined piezoresistive proximal probe with integratedbimorph actuator for aligned single ion implantation  

SciTech Connect

The authors report a microfabrication procedure ofself-actuated piezoresistive scanning probes (SAPSPs). They are designedfor a SAPSP instrument that is integrated with an ion beam for alignedsingle ion implantation in ultrahigh vacuum. The novelty of the design isan integrated hollow pyramid, instead of a previously mechanically handmounted pyramid [J. Vac. Sci. Technol. B 23, 2798 (2005)]. Thepyramidhas dual purpose. First it collimates the ion beam and suppressessecondary particles from the back side of the cantilever, so thatsecondary particles from the target material can be used for single iondetection. Second the pyramid also provides an atomic force microscopetip for the scanning probe. A crucial step in the fabrication is the backside opening via etching for the hollow pyramid. The fabricationprocedure will be discussed in detail.

Persaud, A.; Ivanova, K.; Sarov, Y.; Ivanov, Tzv.; Volland, B.E.; Rangelow, I.W.; Nikolov, N.; Schenkel, T.; Djakov, V.; Jenkins, D.W.K.; Meijer, J.; Vogel, T.

2006-10-01

153

Early complications of permanent pacemaker implantation: no difference between dual and single chamber systems  

Microsoft Academic Search

OBJECTIVE--To evaluate the incidence of intraoperative and early postoperative complications (up to two months after implant) of endocardial permanent pacemaker insertion in all patients under-going a first implant at a referral centre. METHODS--Prospective evaluation of all endocardial pacemaker implantation procedures performed from April 1992 to January 1994 carried out by completion of standard audit form at implant. Patients' demographic data,

R. K. Aggarwal; D. T. Connelly; S. G. Ray; J. Ball; R. G. Charles

1995-01-01

154

Lithium ion implantation and annealing of MgO single crystals  

Microsoft Academic Search

Nominally pure MgO crystals were implanted with lithium ions with different energies and fluences. The defect profile induced by the implantation was primarily characterized by Rutherford backscattering spectrometry and optical absorption measurements. Several absorption bands, associated with oxygen vacancies and higher-order defects involving oxygen, were observed. No evidence was found for the formation of Li colloids during implantation. Thermal annealings

B. Savoini; R. González; R. C. da Silva; E. Alves

2007-01-01

155

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.

Anand, Ullas; Mehta, D. S.

2012-01-01

156

Early single-center experience in sutureless aortic valve implantation in 120 patients.  

PubMed

OBJECTIVE: The study objective was to evaluate the safety and efficacy of sutureless self-expanding nitinol stent-frame aortic valve prostheses made of equine pericardium implanted in patients with symptomatic aortic valve disease. METHODS: We performed a retrospective analysis of 120 patients (mean age, 76.7 ± 5.9 years) who underwent isolated aortic valve replacement or in combination with other cardiovascular procedures. Preoperatively, Society of Thoracic Surgeons score was determined. Transthoracic echocardiography and clinical outcome evaluation were performed at the time of discharge and at 6, 12, and 18 months follow-up, respectively. RESULTS: A total of 71 of 120 patients underwent isolated sutureless aortic valve replacement (mean aortic crossclamp time, 37 ± 11 minutes; mean bypass time, 62 ± 18 minutes). Coronary bypass grafting was performed in 30 patients. Overall mean Society of Thoracic Surgeons score was 14.8% ± 10%. Thirty-day mortality rate was 6.7% overall and 1.4% in stand-alone procedures. During a mean follow-up of 313 days, 3 more deaths occurred. The reoperation rate was 4.2%. Mean and peak transvalvular pressure gradients were 9 mm Hg (4-13 mm Hg) and 14 mm Hg (8-22 mm Hg) at discharge, respectively. In 8 patients (6.7%), permanent pacemaker implantation was necessary. No thromboembolic events or bleedings related to the bioprosthesis were observed. CONCLUSIONS: In this large single-center experience with sutureless aortic valve replacement, the surgical procedure is shown to be safe and time-saving. In view of the excellent hemodynamic results and shortening of aortic crossclamp and bypass times, we notice advantages especially in high-risk patients. Minimally invasive access seems to be facilitated. The long-term durability of this prosthesis has yet to be determined. PMID:23473011

Eichstaedt, Harald C; Easo, Jerry; Härle, Tobias; Dapunt, Otto E

2013-03-01

157

Immediate Occlusal Loading of NanoTite™ Tapered Implants: A Prospective 1-Year Clinical and Radiographic Study.  

PubMed

Background: During the last decade, high success rates have been reported for implants placed with immediate loading procedures, especially when bone quality and quantity provide good implant stability. In many of these studies, straight-walled implants with moderately rough surfaces were employed. Tapered implants are becoming increasingly more popular due to standardized drilling protocols and reports of high initial primary stability. Purpose: The aim of the present prospective, single center clinical study was to evaluate surface topographical analysis and the clinical and radiographic outcomes of the NanoTite™ (BIOMET 3i, Palm Beach Gardens, FL, USA) Tapered Implant when used for immediate loading of fixed prostheses and single-tooth restorations. Materials and Methods: Forty-two patients who needed implant treatment and met admission criteria agreed to participate in the study and were consecutively enrolled. Surgical implant placement requirements consisted of a final torque of a least 30?Ncm prior to final seating and an implant stability quotient above 55. A total of 139 NanoTite Tapered implants (112 maxillary and 27 mandibular) were placed by one investigator, and the majority of these implants (n?=?77/55%) were placed in posterior regions, and in soft bone (n?=?90/65%). A total of 57 prosthetic constructions were evaluated consisting of 20 single-tooth restorations, 30 fixed partial dentures, and 7 complete, fixed maxillary restorations. Radiographs were taken at baseline and at 12 months of follow-up. Results: Of the 139 study implants, one implant failure was declared. The overall cumulative survival rate at 1 year is 99.4%. Mean marginal bone resorption is 1.01?mm (SD 0.85) during the first year of function. Conclusion: Although limited to the short follow-up, immediate loading of NanoTite Tapered implants seems to be a viable option in implant rehabilitation, when insertion torque of at least 30?Ncm is achieved. Further studies are needed to authenticate the finding of this study. PMID:22251669

Ostman, Pär-Olov; Wennerberg, Ann; Ekestubbe, Annika; Albrektsson, Tomas

2012-01-17

158

Technique for fabricating a cement-retained single-unit implant-supported provisional restoration in the esthetic zone.  

PubMed

The fabrication of provisional restorations is an important stage in implant treatment. In the esthetic zone, the potential for error without the use of provisional restorations in the selection of the abutments, framework design, appropriate vertical dimension of occlusion, occlusal profile, and the esthetic interpretation may be significant. Provisional restorations are indicated in esthetic zones, for the contouring of the gingiva, to achieve an acceptable emergence profile, to have custom-guided tissue healing, and to induce appropriate soft-tissue topography. This article describes the fabrication of a provisional restoration for a single-unit implant-supported crown. PMID:16126084

Ganddini, Mario R; Tallents, Ross H; Ercoli, Carlo; Ganddini, Rafael

2005-09-01

159

Tooth about Zinc  

MedlinePLUS

... 07, 2013 About | Contact InfoBites The Tooth About Zinc Article Chapters The Tooth About Zinc send to printer From its involvement in a ... immune system to its role in cell growth, zinc is an essential mineral for the human body. ...

160

The Kaiser's tooth  

Microsoft Academic Search

The recovery of DNA from teeth is usually associated with the destruction of the evidential tooth using, for instance a special grinding mill. In some cases, however, a minimal invasive method of DNA retrieval with a high recovery is required particularly when historical material has to be investigated. A tooth attributed to the German Emperor Wilhelm II was the only

H. Pfeiffer; S. Benthaus; B. Rolf; B. Brinkmann

2003-01-01

161

Experience and implantation techniques with a new single-pass lead VDD pacing system.  

PubMed

Thirty-six patients were implanted with a single-lead atrial-synchronous ventricular pacing (VDD) system at our center in the first and second phases of a clinical trial between October 1987 and December 1989. The clinical system comprised a pulse generator in conjunction with a pacing lead incorporating two diagonal atrial bipolar (DAB) electrodes designed to lie in the mid-to upper-right atrium and a distal tip electrode for ventricular pacing and sensing. Twenty five of the patients had complete heart block, ten had second-degree block, and one had AV nodal block. A modified Bruce protocol limiting treadmill speed to 1.7 miles per hour was used to establish sinus node competency as evidenced by sustained sinus rate increase in a more-or-less linear fashion. The mean acute P wave amplitude measured at implant was 1.66 mV +/- 1.04 SD; the mean P wave amplitude (minimum and maximum, both sitting and supine) for all patients at all follow-up (N = 420) was 1.54 mV +/- 0.9 SD. The follow-up interval for all patients ranged from a minimum of 13 days and a maximum of 762 days, with a mean of 261 +/- 206 days as of December 1, 1989. Four dislodgments of the ventricular electrode occurred with the more pliable of two passive fixation mechanisms used on the lead; atrial sensing remained intact at all times with both fixation systems. Changes in atrial sensing threshold were quite frequent during the early follow-up visits due to electrode movement in the right atrium; however, adequate ventricular tracking of the atrial rate was achieved in all cases once the threshold values were established initially, even though several patients required atrial sensing of 0.2 mV at some of the follow-up visits. Two patients presented with pacemaker-mediated tachycardia associated with retrograde conduction, which was resolved with reprogramming; they are presently maintaining atrial synchrony in the VDD mode. Successful single-lead VDD pacing with consistent P wave sensing has been achieved with this atrial rate responsive system. PMID:1695750

Longo, E; Catrini, V

1990-07-01

162

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

163

[Results of rehabilitation of patients after cochlear implantation of a single-channel extracochlear neuroprosthesis manufactured in Czechoslovakia].  

PubMed

The authors present an account of the results of rehabilitation of the first three subjects after cochlear implantation of a Czechoslovak single-channel neuroprosthesis. The results of rehabilitation were evaluated by means of specially designed videotests and audiotests to make the results comparable with results of neuroprostheses implanted abroad. Based on these tests--in particular MSD--they reached the unequivocal conclusion that the results of cochlear implantation of the Czechoslovak extracochlear neuroprosthesis, as far as rehabilitation is concerned, compare favourably with results achieved by other neuroprosthesis of this type. In all three patients the neuroprosthesis mediates to the patients information on the presence of sound, in many instances it makes identification of this sound possible. In combination with lip-reading the patients are able without major problems to communicate with the environment. Resocialization of the operated patients was achieved. PMID:2731202

Novák, A; Veldová, Z; Jiránková, D

1989-03-10

164

Synthesis of Room-Temperature Ferromagnetic Cr-doped TiO?(110) Rutile Single Crystals using Ion Implantation  

SciTech Connect

Ferromagnetic Cr-doped rutile TiO? single crystals were synthesized by high-temperature ion implantation. The associated structural, compositional and magnetic properties were studied by x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, proton induced x-ray emission, x-ray diffraction, Cr K- and L-shell near-edge x-ray absorption spectroscopy, and vibrating sample magnetometry. Cr was distributed uniformly to the depth of about 300 nm with an average concentration of ~1 at. %. The samples are semiconducting and ferromagnetic as implanted, with a saturation magnetization of 0.29???B/Cr atom at room temperature. Cr is in a formal oxidation state of +3 throughout the implanted region, and no CrO? is detected.

Shutthanandan, V.; Thevuthasan, Suntharampillai; Droubay, Timothy; Heald, Steve M.; Engelhard, Mark H.; McCready, David E.; Chambers, Scott A.; Nachimuthu, Ponnusamy; Mun, B. S.

2006-01-01

165

Strategic considerations in treatment planning: deciding when to treat, extract, or replace a questionable tooth.  

PubMed

Prosthodontists face the difficult task of judging the influence and significance of multiple risk factors of periodontal, endodontic, or prosthetic origin that can affect the prognosis of an abutment tooth. The purpose of this review is to summarize the critical factors involved in deciding whether a questionable tooth should be treated and maintained, or extracted and possibly replaced by dental implants. A MEDLINE (PubMed) search of the English, peer-reviewed literature published from 1966 to August 2009 was conducted using different keyword combinations including treatment planning, in addition to decision making, periodontics, endodontics, dental implants, or prosthodontics. Further, bibliographies of all relevant papers and previous review articles were hand searched. Tooth maintenance and the acceptance of risks are suitable when: the tooth is not extensively diseased; the tooth has a high strategic value, particularly in patients with implant contraindications; the tooth is located in an intact arch; and the preservation of gingival structures is paramount. When complete-mouth restorations are planned, the strategic use of dental implants and smaller units (short-span fixed dental prostheses), either tooth- or implant-supported, as well as natural tooth abutments with good prognoses for long-span FDPs, is recommended to minimize the risk of failure of the entire restoration. PMID:20654764

Zitzmann, Nicola U; Krastl, Gabriel; Hecker, Hanjo; Walter, Clemens; Waltimo, Tuomas; Weiger, Roland

2010-08-01

166

Productivity Improvement for the SHX--SEN's Single-Wafer High-Current Ion Implanter  

SciTech Connect

Equipment productivity is a critical issue for device fabrication. For ion implantation, productivity is determined both by ion current at the wafer and by utilization efficiency of the ion beam. Such improvements not only result in higher fabrication efficiency but also reduce consumption of both electrical power and process gases. For high-current ion implanters, reduction of implant area is a key factor to increase efficiency. SEN has developed the SAVING system (Scanning Area Variation Implantation with Narrower Geometrical pattern) to address this opportunity. In this paper, three variations of the SAVING system are introduced along with discussion of their effects on fab productivity.

Ninomiya, Shiro; Ochi, Akihiro; Kimura, Yasuhiko; Yumiyama, Toshio; Kudo, Tetsuya; Kurose, Takeshi; Kariya, Hiroyuki; Tsukihara, Mitsukuni; Ishikawa, Koji; Ueno, Kazuyoshi [SEN Corporation, 1501, Imazaike, Saijo, Ehime, 799-1362 (Japan)

2011-01-07

167

Splinting osseointegrated implants and natural teeth in partially edentulous patients: a systematic review of the literature.  

PubMed

Dental implants in partially edentulous patients are a predictable therapeutic option. In patients with reduced bone volume, tooth-to-implant connected prostheses have been described as a treatment option. In this systematic review, the incidence of biologic and technical complications and the long-term survival rates of tooth-implant supported fixed partial dentures (FPDs) are analyzed. In cases where a natural tooth is connected with an implant to support a FPD, a rigid connection should be preferred. PMID:21073343

Mamalis, Anastasios; Markopoulou, Kleopatra; Kaloumenos, Konstatinos; Analitis, Antonis

2010-11-12

168

Preliminary three-dimensional analysis of tooth movement and arch dimension change of the maxillary dentition in Class II division 1 malocclusion treated with first premolar extraction: conventional anchorage vs. mini-implant anchorage  

PubMed Central

Objective This study aimed to compare the effects of conventional and orthodontic mini-implant (OMI) anchorage on tooth movement and arch-dimension changes in the maxillary dentition in Class II division 1 (CII div.1) patients. Methods CII div.1 patients treated with extraction of the maxillary first and mandibular second premolars and sliding mechanics were allotted to conventional anchorage group (CA, n = 12) or OMI anchorage group (OA, n = 12). Pre- and post-treatment three-dimensional virtual maxillary models were superimposed using the best-fit method. Linear, angular, and arch-dimension variables were measured with software program. Mann-Whitney U-test and Wilcoxon signed-rank test were performed for statistical analysis. Results Compared to the CA group, the OMI group showed more backward movement of the maxillary central and lateral incisors and canine (MXCI, MXLI, MXC, respectively; 1.6 mm, p < 0.001; 0.9 mm, p < 0.05; 1.2 mm, p < 0.001); more intrusion of the MXCI and MXC (1.3 mm, 0.5 mm, all p < 0.01); less forward movement of the maxillary second premolar, first, and second molars (MXP2, MXM1, MXM2, respectively; all 1.0 mm, all p < 0.05); less contraction of the MXP2 and MXM1 (0.7 mm, p < 0.05; 0.9 mm, p < 0.001); less mesial-in rotation of the MXM1 and MXM2 (2.6°, 2.5°, all p < 0.05); and less decrease of the inter-MXP2, MXM1, and MXM2 widths (1.8 mm, 1.5 mm, 2.0 mm, all p < 0.05). Conclusions In treatment of CII div.1 malocclusion, OA provided better anchorage and less arch-dimension change in the maxillary posterior teeth than CA during en-masse retraction of the maxillary anterior teeth.

Park, Heon-Mook; Kim, Byoung-Ho; Yang, Il-Hyung

2012-01-01

169

[IMZ implants in the treatment of the shortened dental arch in the upper and lower jaws].  

PubMed

The aim of this study was to evaluate the long-term prognosis after insertion of 510 IMZ-implants in case of free-end situations of the upper and lower jaw and prosthodontic restoration. We examined 222 patients prospectively who were treated in a dental practice because of uni- or bilateral free-end situation between 1984 and 1996. Affected and crowned teeth which were neighbouring the implant-based suprastructure, were blocked with these by use of bridge-restorations or attachments. In all the other cases purely implant-based bridge or single-tooth restorations were inserted. Clinical parameters as for example the peri-implant tissue reaction, sulcus depths as well as implant mobility and radiological findings were documented and evaluated statistically. In case of pure implant-based suprastructures we found six implant losses (1.2%), whereas in case of combined tooth-implant-based prosthodontic restorations 20 losses (3.9%) were found. PMID:12498042

Willer, Jürgen; Noack, Nicole; Ellwanger, Ulf; Hoffmann, Jürgen

2002-01-01

170

N and Ar ion-implantation effects in SiO2 films on Si single-crystal substrates  

Microsoft Academic Search

The chemistry of an argon-ion-irradiated interface between an amorphous silicon dioxide film and a silicon single-crystal substrate was studied by determining the kind and depth distribution of compounds formed after nitrogen implantation at a depth more shallow than the SiO2 film thickness. With this study we intended to obtain some insight into the chemical and physical processes involved in the

P. Mazzoldi; A. Carnera; F. Caccavale; M. L. Favaro; A. Boscolo-Boscoletto; G. Granozzi; R. Bertoncello; G. Battaglin

1991-01-01

171

A new generation of single-ended Van de Graaff accelerators for ion implantation and ion beam analysis  

Microsoft Academic Search

High voltage Engineering Europa B.V., The Netherlands developed a new generation of single-ended Van de Graaff accelerators for ion implantation and ion beam analysis. The new HVEE Van de Graaff accelerators are equipped with a unique (patented) ion source exchange system capable of handling four lands of ion sources, mass separation at high voltage level and an X-ray intensity suppression

H. A. P. van Oosterhout

1990-01-01

172

Nanomechanical characterization of cavity growth and rupture in hydrogen-implanted single-crystal BaTiO{sub 3}  

SciTech Connect

A thermodynamic model of cavity nucleation and growth in ion-implanted single-crystal BaTiO{sub 3} 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 H{sub 2} 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. [Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States); Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, South Carolina 29208 (United States); Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States)

2005-04-01

173

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

174

Tooth - abnormal shape  

MedlinePLUS

Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. Abnormally shaped teeth can result from many different conditions. Specific diseases can have a profound effect ...

175

Tooth decay - early childhood  

MedlinePLUS

Bottle mouth; Bottle carries; Baby bottle tooth decay; Early childhood caries (ECC) ... chap 304. Ribeiro NM, Ribeiro MA. Breastfeeding and early childhood caries: a critical review. J Pediatr (Rio J). ...

176

Replacing a Missing Tooth  

MedlinePLUS

... patient without a bone graft is a fixed bridge. The missing tooth is restored with an artificial ... be crowned to give adequate support to the bridge. This type of prosthesis is not removable. Its ...

177

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 ...

178

Cavities/Tooth Decay  

MedlinePLUS

... fitting well, allowing decay to begin underneath them. Eating disorders. Anorexia and bulimia can lead to significant tooth ... begins dissolving the enamel. In addition, people with eating disorders may sip soda or other acidic drinks throughout ...

179

Genes affecting tooth morphogenesis.  

PubMed

The development of dentition is a fascinating process that encompasses a complex series of epithelial-mesenchymal interactions involving growth factors, transcription factors, signal receptors and other soluble morphogens. It is not surprising that such a complex process is prone to disturbances and may result in tooth agenesis. Initial discoveries indicating that the homeo-domain protein MSX1 and the paired-domain transcription factor PAX9 are causative genes in tooth morphogenesis were made in mice. Both genes are co-expressed in dental mesenchyme and either one, when homozygously deleted, results in an arrest at an early developmental stage. Heterozygous Pax9 or Msx1 mice have normal teeth, however, double heterozygous Pax9/Msx1 mice show a phenotype of arrested tooth development which can be rescued by transgenic expression of Bmp4, a very influential signaling factor in many developmental processes. We have obtained mounting evidence for a partnership between PAX9 and MSX1 within the tooth-specific Bmp4 signaling pathway. In humans, unlike in mice, a heterozygous mutation in either PAX9 or MSX1 suffices to cause tooth agenesis of a predominantly molar or more premolar pattern, respectively. Our laboratory and others have identified several PAX9 and MSX1 mutations in families with non-syndromic forms of autosomal dominant posterior tooth agenesis. We have also identified families with tooth agenesis in whom PAX9 and MSX1 mutations have been excluded opening up the possibilities for the discovery of other genes that contribute to human tooth agenesis. PMID:17651126

Kapadia, H; Mues, G; D'Souza, R

2007-08-01

180

Reliability of Circumferential Bone Level Assessment around Single Implants in Healed Ridges and Extraction Sockets Using Cone Beam CT.  

PubMed

Purpose: Cone beam computerized tomography (CBCT) provides three-dimensional information and could absolutely be useful for evaluating circumferential implant bone levels. However, the accuracy and precision of the technique has not been described. The aim of the study was to assess the accuracy and precision of CBCT (i-CAT®, Imaging Sciences International®, Hatfield, PA, USA) using periapical radiographs (PA) as a reference and to evaluate the circumferential bone level on CBCT around immediately loaded single implants placed in healed ridges (CIT, conventional implant treatment) and extraction sockets (IIT, immediate implant placement). Materials and Methods: PA and CBCT radiographs were obtained from 26 single Astra Tech Osseospeed™ implants (Astra Tech AB, Mölndal, Sweden) 1 year after loading in respectively healed ridges (CIT) or extraction socket (IIT). For accuracy analysis, the three mesial and three distal interproximal levels obtained by CBCT were pooled to enable a comparison with PA. Precision was analyzed by intra- and interexaminer reliability calculation from mesial and distal sites on CBCT. The circumferential bone level considered all eight positions assessed on CBCT. Results: Accuracy of CBCT was low (R?=?0.325/p?=?.019) given the fact that bone level of the total group was 0.70?mm (standard deviation [SD] 0.78, range 0.00-3.20) on PA and 0.23?mm (SD 0.27, 0.00-1.20) on CBCT (p?implant treatment is evenly preserved when implants are immediately loaded in extraction sockets or in healed bone. PMID:22008055

Raes, Filiep; Renckens, Liesbet; Aps, Johan; Cosyn, Jan; De Bruyn, Hugo

2011-10-18

181

Note: Laser ablation technique for electrically contacting a buried implant layer in single crystal diamond  

SciTech Connect

The creation of thin, buried, and electrically conducting layers within an otherwise insulating diamond by annealed ion implantation damage is well known. Establishing facile electrical contact to the shallow buried layer has been an unmet challenge. We demonstrate a new method, based on laser micro-machining (laser ablation), to make reliable electrical contact to a buried implant layer in diamond. Comparison is made to focused ion beam milling.

Ray, M. P.; Baldwin, J. W.; Butler, J. E.; Pate, B. B. [U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Feygelson, T. I. [SAIC, 1220 12th St. SE, Washington, DC 20003 (United States)

2011-05-15

182

Single-Step Resection and Reconstruction Using Patient-Specific Implants in the Treatment of Benign Cranio-Orbital Tumors.  

PubMed

PURPOSE: The aim of this study was to evaluate surgical outcomes using patient-specific prostheses produced by computer-aided design and manufacturing for primary reconstruction in patients with benign cranio-orbital tumors. Polyetheretherketone was used to manufacture the implants. MATERIALS AND METHODS: The present study included 3 patients who underwent fronto-orbito-pterional craniotomy using individual custom-made surgical guides. Patient-specific polyetheretherketone prostheses were used for reconstruction during the same surgery. All patients underwent esthetic examination (facial and orbital symmetry, globe projection and position), ophthalmologic examination (diplopia with the Hess-Lancaster test, visual field and acuity), and radiologic evaluations (computed tomography and magnetic resonance imaging) during the preoperative and follow-up periods. Operating time and short- and long-term complications were recorded. RESULTS: The immediate and long-term morphologic results were satisfactory; in particular, ocular globe position and projection were correct. After 25 to 31 months, none of the patients developed implant-related complications, such as infection, extrusion, or malposition. Two-year postoperative computed tomograms and magnetic resonance images showed no recurrences. CONCLUSION: Single-step resection and reconstruction with computer-aided designed and manufactured implants is a challenging new technique that decreases operative time and morbidity. The implants adequately restore an anatomically complex area with satisfactory cosmetic results. PMID:23676776

Gerbino, Giovanni; Bianchi, Francesca Antonella; Zavattero, Emanuele; Tartara, Fulvio; Garbossa, Diego; Ducati, Alessandro

2013-05-13

183

Clinical and mechanical evaluation of screw-retained implant-supported zirconia restorations. A 36 months prospective clinical study.  

PubMed

This study evaluated the clinical performance of screwed customized zirconia abutments. Additionally, the marginal fit between the selected implant components was measured and the clinical gingival response was monitored. Thirty patients were consecutively selected for a prospective study of 30 implant-supported restorations. Customized zirconia abutment complexes were prepared, then ceramic was performed directly. The abutments were screwed onto the implants and restored with all-ceramic crowns. Plaque and gingival indices were recorded monthly intervals over a 12- month period. All ceramic zirconia abutments offered sufficient stability to support implantsupported single-tooth reconstructions in anterior and premolar regions. The soft and hard tissue reaction toward zirconia was favorable. PMID:23756842

Di Alberti, L; Di Alberti, C; Donini, F; Lo Muzio, L; Cadrobbi, F; D'Agostino, A; De Santis, D; Bertossi, D

2013-06-11

184

A comparative study of the electrical properties of heavily Al implanted, single crystalline and nanocrystalline SiC  

NASA Astrophysics Data System (ADS)

The electrical properties of heavily Al doped single and nanocrystalline 4H-SiC layers on semi-insulating 4H-SiC substrate, prepared by multienergy, high-fluence Al implantation and subsequent furnace annealing, are investigated by sheet resistance and Hall effect measurements. Ion beam induced crystallization is used to prepare the nanocrystalline SiC layers. The doping levels are chosen around the solid solubility limit of 2×1020 cm-3 in the range from 5×1019 to 1.5×1021 cm-3. The comparison of the results shows that heavily Al doped single crystalline SiC layers have superior conduction properties. The lowest resistivities measured at room temperature are 0.08 and 0.8 ? cm for the single crystalline and nanocrystalline samples, respectively. Recent results on enhanced Al acceptor activation in nanocrystalline SiC cannot be confirmed. There is an upper limit for the hole concentration in the nanocrystalline samples independent of the Al supersaturation level in the as-implanted state due to outdiffusion of Al in excess to the solid solubility limit during annealing. In contrast to the nanocrystalline SiC layers the as-implanted Al profile in single crystalline material remains stable after annealing even for concentrations above the solid solubility limit. Therefore, in single crystalline material efficient impurity band conduction due to strongly interacting acceptors can be achieved in the range of supersaturation. For lower doping levels impurity band conduction is more effective in nanocrystalline SiC.

Heera, V.; Madhusoodanan, K. N.; Skorupa, W.; Dubois, C.; Romanus, H.

2006-06-01

185

Dual-coil vs single-coil active pectoral implantable defibrillator lead systems: defibrillation energy requirements and probability of defibrillation success at multiples of the defibrillation energy requirements  

Microsoft Academic Search

Aims The aim of the study was to compare the defibrillation energy requirements and the probability of successful defibrillation at multiples of the minimum defibrillation energy requirements in active pectoral implantable defibrillators with single- and dual-coil lead systems.Methods and ResultsEighty-three consecutive patients undergoing implantation of an active pectoral cardioverter-defibrillator were randomized to receive a dual- or single-coil lead system. Defibrillators

B Schulte; J Sperzel; J Carlsson; T Schwarz; W Ehrlich; H. F Pitschner; J Neuzner

2001-01-01

186

Analysis of mechanical behavior of implant-supported prostheses in the anterior maxilla: analysis by speckle pattern interferometry  

NASA Astrophysics Data System (ADS)

The use of implants to rehabilitation of total edentulous, partial edentulous or single tooth is increasing, it is due to the high rate of success that this type of treatment present. The objective of this study was to analyze the mechanical behavior of different positions of two dental implants in a rehabilitation of 4 teeth in the region of maxilla anterior. The groups studied were divided according the positioning of the implants. The Group 1: Internal Hexagonal implant in position of lateral incisors and pontic in region of central incisors; Group 2: Internal Hexagonal implant in position of central incisors and cantilever of the lateral incisors and Group3 - : Internal Hexagonal implants alternate with suspended elements. The Electronic Speckle Pattern Interferometry (ESPI) technique was selected for the mechanical evaluation of the 3 groups performance. The results are shown in interferometric phase maps representing the displacement field of the prosthetic structure.

Corrêa, Cássia B.; Ramos, Nuno V.; Monteiro, Jaime; Vaz, Luis G.; Vaz, Mario A. P.

187

Advantages and Disadvantages of Double Threaded Dental Implant Screws As Opposed to Single-Threaded: A Study from a Biomechanical Perspective by the Finite Element Method  

NASA Astrophysics Data System (ADS)

The purpose of the present article is to study the advantages from a biomechanical point of view of the use of a double-threaded dental implant over the more common single-threaded one. For this purpose a 3D model of a portion of the jaw was generated. In this model four different bone areas were distinguished (transition cortical, transition trabecular, bulk cortical and bulk trabecular). Not only was the portion of the jaw created with CAD software but also two different implants geometries, one with only one thread (single-threaded) and the other with two threads (double-threaded). The loading condition was defined as 150 N intrusive forces and 15 N lingual-labial forces acting on the implant. The results of the present study shown that from a macroscopic point of view, the choice of one or other of the dental implants does not make a significant difference in the general behaviour of the jaw. In spite of this and notwithstanding the effects of the transition bone-implant, the stress distribution achieved by the single-threaded dental implant is more uniform. This effect is better for the biomechanics of the jaw. The advantage presented by the double threaded implant is that due to its larger surface the osseointegration is better than in the single-threaded version.

Álvarez-Arenal, A.; de Cos Juez, F. J.; Lasheras, F. Sánchez; Quevedo, M. Mauvezin

2009-08-01

188

Clinical experience with a novel subcutaneous implantable defibrillator system in a single center  

Microsoft Academic Search

Background  Implantable cardioverter-defibrillators (ICDs) reduce mortality in both primary and secondary prevention, but are associated\\u000a with substantial short- and long-term morbidity. A totally subcutaneous ICD (S-ICD) system has been developed. We report the\\u000a initial clinical experience of the first 31 patients implanted at our hospital.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  All patients had an ICD indication according to the ACC\\/AHA\\/ESC guidelines. The first 11 patients were

Lara Dabiri Abkenari; Dominic A. M. J. Theuns; Suzanne D. A. Valk; Yves Van Belle; Natasja M. de Groot; David Haitsma; Agnes Muskens-Heemskerk; Tamas Szili-Torok; Luc Jordaens

189

Evaluation of implants placed immediately or delayed into extraction sites  

PubMed Central

Aims and objectives: To compare the success rate of implant placed immediately in extraction socket vs implant placed delayed in extraction socket. Materials and Methods: The study comprised of 8 patients (6 male and 2 female, aged from 14 to 58 year) for evaluation of implant placement immediately (i.e. Group – A) or delayed (i.e. Group – B) into extraction site, in which at 12 sites implants were placed. Results: The inclusion criteria for implantation was tooth/teeth with one or two degree mobility, root stumps, tooth with failure root canal treatment and extraction sockets. HI-TEC TRX-OP (Life Care) with abutment, non-submerged, tapered at apical 5 mm, sand-blasted & acid etched surfaced implants were used. These are one stage single implants made of commercially pure titanium. The length of implants used was 10 mm and 13 mm and diameter was 3.70 mm and 4.50 mm. The vertical bone dimension was determined by palpation and radiograph (intra-oral periapical, orthopantomograph and dentascan in some patients). Gingival condition, bone condition was examined clinically and radiographically. Discussion: Post-operative evaluation was done under clinical parameters (i.e. Pain (VAS), Swelling, Stability (By Glickman method), Gingival status, Probing depth (By Williams Periodontal probe), Patient's compliance / satisfaction, Complications (If any) and Radiological parameters was (Intra-oral periapical radiograph, orthopantomograph, Dentascan). Conclusion: Overall conclusion drawn from this study was that both the groups are showing similar results but Group-A is slightly better than Group-B

Pal, U. S.; Dhiman, Neeraj Kumar; Singh, Geeta; Singh, R. K.; Mohammad, Shadab; Malkunje, Laxman R.

2011-01-01

190

Single chip CMOS imagers and flexible microelectronic stimulators for a retina implant system  

Microsoft Academic Search

We are presenting CMOS image sensors and a microelectronic stimulator for realization of a retina implant system that will provide visual sensations using electrostimulation to patients suffering from photoreceptor degeneration. Four CMOS image sensors implementing different principles, e.g. linear characteristic, logarithmic characteristic, and local brightness adaptation have been developed. These are directly attached to a digital filter and signal processor

M Schwarz; L Ewe; R Hauschild; B. J Hosticka; J Huppertz; S Kolnsberg; W Mokwa; H. K Trieu

2000-01-01

191

Transradial artery Palmaz-Schatz coronary stent implantation: Results of a single-center feasibility study  

Microsoft Academic Search

The purpose of this study was to evaluate the feasibility and safety of implantation of unsheathed Palmaz-Schatz coronary stents introduced via the radial artery. Anticoagulation after coronary stenting carries the risk of vascular complications if large-bore guiding catheters are introduced via the femoral artery. These complications have serious local sequelae and lead to suboptimal anticoagulation and prolonged hospitalization. By combining

Ferdinand Kiemeneij; Gert Jan Laarman

1995-01-01

192

A new generation of single-ended Van de Graaff accelerators for ion implantation and ion beam analysis  

NASA Astrophysics Data System (ADS)

High voltage Engineering Europa B.V., The Netherlands developed a new generation of single-ended Van de Graaff accelerators for ion implantation and ion beam analysis. The new HVEE Van de Graaff accelerators are equipped with a unique (patented) ion source exchange system capable of handling four lands of ion sources, mass separation at high voltage level and an X-ray intensity suppression system. The accelerators are able to produce a large variety of continuously, homogeneous and highly collimated mass-analyzed ion beams of several hundred ?A in the energy range from 50 keV up to l MeV (l MV model) or from 100 keV up to 2 MeV (2 MV model), using singly charged ions, whereby the maximum energy can be easily reached and maintained without conditioning and virtually no X-rays are produced. Combined with two dedicated end stations (one for ion beam analysis using RBS, channeling, NRA and PIXE, and one with an automatic wafer-handling system for both single-wafer implantation and batch processing), these systems are very suitable for research as well as industrial applications.

van Oosterhout, H. A. P.

1990-04-01

193

[Tooth wear. Classification and terminology].  

PubMed

Tooth wear rarely occurs as a result of one factor alone. Non-carious loss of tooth tissue can be subdivided into attrition, demastication, abrasion, fractionation, and erosion. Clinically, the tooth tissue loss may result from any combination of these types of wear. The first essential principle in the management of tooth wear is, as far as possible, to remove the cause. Secondly, restoration may be indicated. PMID:11924384

de Baat, C; van Nieuw Amerongen, A

1997-04-01

194

Tooth Quality in Dental Fluorosis  

Microsoft Academic Search

Dental fluorosis (DF) affects the appearance and structure of tooth enamel and can occur following ingestion of excess fluoride during critical periods of amelogenesis. This tooth malformation may, depending on its severity, influence enamel and dentin microhardness and dentin mineralization. Poor correlation between tooth fluoride (F) concentration and DF severity was shown in some studies, but even when a correlation

A. P. G. F. Vieira; R. Hanocock; H. Eggertsson; E. T. Everett; M. D. Grynpas

2005-01-01

195

A Radiographic Comparison of Progressive and Conventional Loading on Crestal Bone Loss and Density in Single Dental Implants: A Randomized Controlled Trial Study  

PubMed Central

Objective: Crestal bone loss is a biological complication in implant dentistry. The aim of this study was to compare the effect of progressive and conventional loading on crestal bone height and bone density around single osseointegrated implants in the posterior maxilla by a longitudinal radiographic assessment technique. Materials and Methods: Twenty micro thread implants were placed in 10 patients (two implants per patient). One of the two implants in each patient was assigned to progressive and the other to conventional loading groups. Eight weeks after surgery, conventional implants were restored with a metal ceramic crown and the progressive group underwent a progressive loading protocol. The progressive loading group took different temporary acrylic crowns at 2, 4 and 6 months. After eight months, acrylic crowns were replaced with a metal ceramic crown. Computer radiography of both progressive and conventional implants was taken at 2, 4, 6, and 12 months. Image analysis was performed to measure the height of crestal bone loss and bone density. Results: The mean values of crestal bone loss at month 12 were 0.11 (0.19) mm for progressively and 0.36 (0.36) mm for conventionally loaded implants, with a statistically significant difference (P < 0.05) using Wilcoxon sign rank. Progressively loaded group showed a trend for higher bone density gain compared to the conventionally loaded group, but when tested with repeated measure ANOVA, the differences were not statistically significant (P > 0.05). Conclusion: The progressive group showed less crestal bone loss in single osseointegrated implant than the conventional group. Bone density around progressively loaded implants showed increase in crestal, middle and apical areas.

Ghoveizi, Rahab; Alikhasi, Marzieh; Siadat, Mohammad-Reza; Siadat, Hakimeh; Sorouri, Majid

2013-01-01

196

Lattice-location studies of cerium ions implanted into vanadium single crystals  

NASA Astrophysics Data System (ADS)

The substitutional fraction (fs) of 0.1 at.Ce in vanadium depends on the lattice temperature during implantation and is 0.73, 0.73, and 0.15 at 5, 77, and 300 K, respectively. Increasing the implanted Ce concentration at 300 K to 3.3 at. eads to an increase of fs from 0.15 to 0.66. Postirradiation of VCe systems as produced at 300 K with He ions at 77 K leads to an increase of fs. If the postirradiated systems are warmed up to room temperature fs decreases. It is concluded that Ce-vacancy clusters are formed within the prompt cascade regime and by trapping mobile vacancies. Pre- and postimplantation experiments proved that the increase of fs with Ce concentration is due to cluster dissolution accompanied by the formation of competing vacancy-trapping centers.

Azzam, A.; Meyer, O.

1986-07-01

197

[Ridge preservation after tooth extraction: what do we know today].  

PubMed

Following tooth removal, varying amounts of bone resorption take place due to qualitative and quantitative changes that occur at the alveolar bone around the extraction site. Alveolar bone is a tooth dependent structure and therefore, after a tooth is extracted, dimensional bone reduction takes place both, horizontally and vertically resulting in changes that may lead to esthetic and functional problems. Such deformities of the alveolar ridge may compromise future implant placement as well as esthetic results when a fixed partial denture is constructed in a visible area. In order to preserve ridge dimensions following tooth extraction, particularly where future implant placement is planned, ridge/socket preservation is recommended. Ridge/socket preservation is any procedure undertaken at the time of or following an extraction that is designed to minimize external resorption of the ridge and maximize bone formation within the socket. In certain situations it not advisable to perform ridge preservation at the time of tooth extraction thus, preservation is delayed by few weeks (6-8). This paper reviews the various socket/ridge preservation techniques and the diverse materials used to fill those deficient tissues or prevent their collapse. Scientific literature review is discussed. PMID:24020248

Chackartchi, T; Stabholz, A

2013-04-01

198

Implantable cardioverter defibrillator in maintenance hemodialysis patients with ventricular tachyarrhythmias: a single-center experience.  

PubMed

Patients with hemodialysis (HD) are at risk of death due to cardiac arrhythmias, worsening congestive heart failure (CHF), and noncardiac causes. This study reviews our experience with the use of implantable cardioverter defibrillators (ICDs) in patients with ventricular tachycardia who are under maintenance HD. We retrospectively reviewed 71 consecutive patients who underwent an ICD implantation in our hospital. There were 11 patients under maintenance HD and 60 patients without HD. The group of patients with HD (HD group) was compared with the patients without HD (control group). The mean follow-up period was 30+/-9 vs. 39+/-4 months in the HD group vs. the control group, respectively. Among these patients, 6 in the HD group and 26 in the control group received appropriate ICD therapies. There was no difference in appropriate ICD therapy, time to the first therapy, and electrical storm between the 2 groups. In the HD group, 1 patient underwent surgical removal of the ICD system due to infective endocarditis. There were 5 deaths in the HD group (4 from CHF) and 8 deaths in the control group (4 from CHF). There were no sudden cardiac deaths or arrhythmic deaths in both groups of patients during the follow-up period. However, the overall death rate was significantly higher in the HD group (P<0.01). In HD patients, ICD therapy prevented arrhythmic death, but their rate of nonarrhythmic adverse outcomes was high. This risk-benefit association should be considered before implantation of the device. PMID:19210278

Ito, Itaru; Kono, Koichi; Shinbo, Goro; Tadokoro, Kazuyoshi; Abe, Chikara; Takemura, Naoki; Iemura, Tomomi; Matsuhashi, Noritaka; Nakano, Nobuyuki; Ota, Satoshi; Ishimitsu, Toshihiko; Matsuoka, Hiroaki

2009-01-01

199

Defects in virgin and N+ -implanted ZnO single crystals studied by positron annihilation, Hall effect, and deep-level transient spectroscopy  

Microsoft Academic Search

High-quality single crystals of ZnO in the as-grown and N+ ion-implanted states have been investigated using a combination of three experimental techniques---namely, positron lifetime\\/slow positron implantation spectroscopy accompanied by theoretical calculations of the positron lifetime for selected defects, temperature-dependent Hall (TDH) measurements, and deep level transient spectroscopy (DLTS). The positron lifetime in bulk ZnO is measured to be (151±2)ps and

G. Brauer; W. Anwand; W. Skorupa; J. Kuriplach; O. Melikhova; C. Moisson; H. von Wenckstern; H. Schmidt; M. Lorenz; M. Grundmann

2006-01-01

200

Gum Disease and Men  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

201

Plastic Surgery Procedures (for Gums)  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

202

Periodontal Disease and Systemic Health  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

203

Gum Disease and Women  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

204

American Academy of Periodontology  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

205

Dispelling Myths about Gum Disease  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

206

Gum Disease Risk Assessment Test  

MedlinePLUS

... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...

207

Melatonin Effects on Hard Tissues: Bone and Tooth  

PubMed Central

Melatonin is an endogenous hormone rhythmically produced in the pineal gland under the control of the suprachiasmatic nucleus (SCN) and the light/dark cycle. This indole plays an important role in many physiological processes including circadian entrainment, blood pressure regulation, seasonal reproduction, ovarian physiology, immune function, etc. Recently, the investigation and applications of melatonin in the hard tissues bone and tooth have received great attention. Melatonin has been investigated relative to bone remolding, osteoporosis, osseointegration of dental implants and dentine formation. In the present review, we discuss the large body of published evidence and review data of melatonin effects on hard tissues, specifically, bone and tooth.

Liu, Jie; Huang, Fang; He, Hong-Wen

2013-01-01

208

Melatonin effects on hard tissues: bone and tooth.  

PubMed

Melatonin is an endogenous hormone rhythmically produced in the pineal gland under the control of the suprachiasmatic nucleus (SCN) and the light/dark cycle. This indole plays an important role in many physiological processes including circadian entrainment, blood pressure regulation, seasonal reproduction, ovarian physiology, immune function, etc. Recently, the investigation and applications of melatonin in the hard tissues bone and tooth have received great attention. Melatonin has been investigated relative to bone remolding, osteoporosis, osseointegration of dental implants and dentine formation. In the present review, we discuss the large body of published evidence and review data of melatonin effects on hard tissues, specifically, bone and tooth. PMID:23665905

Liu, Jie; Huang, Fang; He, Hong-Wen

2013-05-10

209

Tooth auto-transplantation as an alternative treatment option: A literature review  

PubMed Central

Rapidly evolving implantation and alveolar ridge reconstruction techniques created a new area in modern dentistry where tooth loss is no longer a problem. Endless variations of implant's length, diameter, surface, and design along with autogenous, alogenous, aloplastic, or xenogenous bone substitutes made it possible to recreate physiological occlusion, esthetic and masticatory function. However, none of nowadays technologies in implant dentistry have the potential to adapt to a growth and development changes of a child's jaw. Therefore, patient's young age is a restriction for implantation and a particular challenge for a dentist willing to restore missing tooth. Thus, tooth auto-transplantation can be a good choice for treatment. The objective of this review is to underline the biologic principles required for successful auto-transplantation of teeth. Limits, indications, technique, and prognosis will be analyzed.

Nimcenko, Tatjana; Omerca, Grazvydas; Varinauskas, Vaidas; Bramanti, Ennio; Signorino, Fabrizio; Cicciu, Marco

2013-01-01

210

Implantable Cardioverter Defibrillator Therapy: A Single Center Experience in Saudi Arabia  

PubMed Central

Introduction: Internal Cardioverter Defibrillators (ICD) has been shown to decrease mortality in patients such as those with structural heart disease or at high risk of sudden cardiac death. To date there is no data regarding the clinical features, and outcomes of ICD patients in Saudi Arabia. Accordingly, we explored the clinical features and outcomes of ICD therapy among Saudis. Methods: Patients who had ICD implantation in King Khalid University Hospital from November 2007 until January 2010 were enrolled. Results: One hundred and eight ICD were implanted between November 2007 and February 2010. The mean age was 58.6±13.2 years. The majority were male 94 (87%), the rate of Diabetes Mellitus (DM) was 58.3%, Hypertension (HTN) was 61.1%, and 63% were smokers. The mean ejection fraction (EF) was 24.5%. Of the 108 patient 90(83.3%) had ICD insertion for primary prevention and 18(16.7%) for secondary prevention. Of the 90 patients who ICD for primary prevention 62 (57.4%) had ischemic cardiomyopathy, 39(36.1%) had dilated cardiomyopathy and 7 (6.5%) had channelopathy. Over a mean follow-up of 18 months 4 (3.7%) died. Conclusions: Our study describes for the first time patients characteristic and outcomes for ICD therapy in Saudi Arabia. Our patients are younger and have higher prevalence of risk factors that those in Western countries.

Hersi, Ahmad S

2010-01-01

211

Modeling of damage accumulation during ion implantation into single-crystalline silicon  

SciTech Connect

A critical review is given on phenomenological models of damage accumulation used in binary collision (BC) computer simulations of the dose dependence of the shape of as-implanted profiles and of the interdependence of channeling and damage buildup. The statistical approach, which assumes the accumulation of amorphous pockets, is found to be the most realistic model for doses below the amorphization threshold. The dynamic simulation of the formation of amorphous layers is described by an improved model. If within a certain depth interval the density of amorphous pockets exceeds a critical value, abrupt amorphization occurs. The model is applied in the Crystal-TRIM code. Using only two empirical parameters, the change of the shape of range distributions with growing dose as well as the formation of amorphous layers during ion bombardment can be simulated. One parameter describes the accumulation of amorphous pockets and depends on the target temperature. The other parameter is independent of temperature and models the onset of amorphization. Results of Crystal-TRIM calculations for B{sup +}, BF{sub 2}{sup +}, P{sup +}, and As{sup +} implantations are compared with a comprehensive set of experimental data on range and damage profiles obtained by secondary ion mass spectroscopy, cross-sectional transmission electron microscopy, and channeling Rutherford backscattering spectroscopy. In general, good agreement between simulations and measurements is found.

Posselt, M.; Schmidt, B. [Research Center Rossendorf, Dresden (Germany). Inst. of Ion Bean Physics and Materials Research; Murthy, C.S. [IBM East Fishkill Facility, Hopewell Junction, NY (United States). Semiconductor Research and Development Center; Feudel, T. [Swiss Federal Inst. of Tech., Zuerich (Switzerland). Integrated Systems Lab.; Suzuki, K. [Fujitsu Labs., Ltd., Atsugi (Japan)

1997-04-01

212

Technical note: gold marker implants and high-frequency jet ventilation for stereotactic, single-dose irradiation of liver tumors.  

PubMed

With reference to radiosurgery of the liver, we describe techniques designed to solve the methodological problem of striking targets subject to respiratory motion with the necessary precision. Implanting a gold marker in the vicinity of the liver tumor was the first step in ensuring the reproducibility of the isocenter's position. An 18-karat gold rod measuring 1.9 x 3 mm was implanted approximately 2 cm from the edge of the tumor as this was displayed in the spiral, thin-slice CT with contrast media. Both the implantation of the marker and the required, CT-controlled biopsy of the liver tumor can be achieved simultaneously with the same puncture needle. The efficiency of high-frequency jet ventilation (HFJV) in neutralizing the targeted organ's respiratory motion during stereotactic single-dose irradiation was evaluated. The procedure was carried out on ten patients without any complications. In the time between treatment planning and irradiation (3 days), no significant marker migration was observable. In all cases, the gold marker (volume: 7.5 mm(3)) was readily observable in the treatment beam using portal imaging. HFJV provided reliable immobilization. The liver motion in each anesthetized patient was limited to under 3.0 mm in all directions. Thus, the correct field settings and target reproducibility were able to be analyzed and documented during the irradiation. The combination of marker and HFJV enables the determination of stereotactic coordinates directly related to the liver itself and, in this way, stereotactic radiation treatment of liver tumors is freed from the uncertainties involved in orientation to bony landmarks, in respiratory motion, and in changes of position in the stereotactic body frame. The method is feasible and can improve the accuracy of stereotactic body radiation therapy. PMID:16417397

Fritz, P; Kraus, H-J; Dölken, W; Mühlnickel, W; Müller-Nolte, F; Hering, W

2006-02-01

213

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.

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

2012-01-01

214

Tooth fragment reattachment technique on a pluri traumatized tooth  

PubMed Central

This case report describes and analyses a tooth fragment reattachment technique used to resolve crown fractures of the anterior teeth. This treatment allows a conservative approach to traumatic coronal lesions offering a better possibility of maintaining aesthetics and function. The authors have illustrated here a clinical case of a fractured incisor. This case is characterized by several traumas on the same tooth that required different therapeutic solutions. We used an easy and ultra-conservative technique without any tooth preparation in the first and third traumatic injuries. In the second trauma, a direct restoration of the fractured tooth was performed. The adhesive reattachment is a simple system to achieve good aesthetic and functional results.Our clinical experiences demonstrated that, when tooth and fragment margins are intact, the reattachment technique without any tooth preparation is a simple and predictable procedure. Quality of adhesion is shown by the retention of the reattached fragment in the second trauma that caused only partial enamel fractures.

Giudice, Giuseppe Lo; Lipari, Frank; Lizio, Angelo; Cervino, Gabriel; Cicciu, Marco

2012-01-01

215

Microflora around teeth and dental implants  

PubMed Central

Background: When an implant is exposed to oral cavity, its surface gets colonized by micro-organisms. The aim of this study is to comparatively assess the microbiological parameters in sulci around the teeth and the crowns supported by dental implants. Materials and Methods: In this prospective, cross-sectional study, 34 partially edentulous patients aged between 40 and 50 years with total 50 anterior maxillary single implants with cemented crowns (depth of sulci <4 mm) and 34 similar teeth in the same jaw of the same patients were included. Excluded were the patients with compromised systemic and periodontal health and smoking habits. None of the patients had used any antimicrobial mouthwashes during at least two weeks before the study. All of the implants (ITI) were at least 6 months in place covered by definitive prostheses. Samples of gingival sulci were taken around teeth with paper cone and transported to Stuart transport medium. Samples were cultured and examined by a dark field microscope and eight laboratory tests were performed to determine the micro-organisms The data were evaluated statistically using Chi-square test (?=0.05). Results: Six anerobic bacteria found in teeth and implants sulci were Gram-positive cocci, Gram-negative cocci, Prevotella, Porphyromonas gingivalis, Bacteroid Fragilis and Fusobacterium. Gram-positive cocci and Gram-negative cocci had maximum and minimum percentage frequency in the two groups, respectively. There were no significant differences between the two groups (P value >0.05). Conclusion: The present study indicated that microflora in implant sulci is similar to the tooth sulci, when the depth of sulci is normal (<4 mm). As a result, implants’ susceptibility to inflammation is the same as teeth.

Shahabouee, Mohammad; Rismanchian, Mansour; Yaghini, Jaber; Babashahi, Akram; Badrian, Hamid; Goroohi, Hossein

2012-01-01

216

Charge density wave transport in heterogeneously doped NbSe3 single crystals by masked ion (B^+, Li^+) implantation  

NASA Astrophysics Data System (ADS)

Charge-density wave is competing electron spectrum instability of superconductivity (SC). CDW transport vs. SC with boundary between CDWs and SC are well known examples of correlated transport of macroscopic numbers of electrons.CDW superconductors include layered dichalcogenides, NbSe3. On selective area medium energy ion (B^+, Li^+) implantation was used to create irradiated/unmodified/irradiated CDW heterostructures with well-defined interfaces on single NbSe3 crystal. The effects of impurities go beyond simply increasing CDW pinning (J.P.McCarten.et.al J.Phys.IV France 9,1999).The dV/dI vs. bias at several temperatures, and zero-bias resistance vs. temperature, where two voltage contacts straddle the interface (near the boundary between B^+/ Li^+-implanted and unimplanted regions) are well studied. Injected charge B^+/Li^+ is a non-isoelectronic impurity. The results of ongoing investigations of similar studies of boron- and lithium-doped NbSe3 will be discussed.

Sasmal, Kalyan; Wijesinghe, Asanga; Wijesundera, Dharshana; Tang, Zhongjia; Guloy, Arnold; Chu, Wei-Kan; Miller, John H.

2013-03-01

217

Pose determination of a cylindrical (dental) implant in three-dimensions from a single two-dimensional radiograph  

PubMed Central

Objectives The aim was to develop an analytical algorithm capable of determining localization and orientation of a cylindrical (dental) implant in three-dimensional (3D) space from a single radiographic projection. Methods An algorithm based on analytical geometry is introduced, exploiting the geometrical information inherent in the 2D radiographic shadow of an opaque cylindrical implant (RCC) and recovering the 3D co-ordinates of the RCC's main axis within a 3D Cartesian co-ordinate system. Prerequisites for the method are a known source-to-receptor distance at a known locus within the flat image receptor. Results Accuracy, assessed from a small feasibility experiment in atypical dental radiographic geometry, revealed mean absolute errors for the critical depth co-ordinate ranging between 0.5 mm and 5.39 mm. This translates to a relative depth error ranging from 0.19% to 2.12%. Conclusions Experimental results indicate that the method introduced is capable of providing geometrical information important for a variety of applications. Accuracy has to be enhanced by means of automated image analysis and processing methods.

Schulze, R K W

2010-01-01

218

Single Phosphorus Ion Implantation into Prefabricated Nanometre Cells of Silicon Devices for Quantum Bit Fabrication  

Microsoft Academic Search

In the near future, devices that employ single atoms to store or manipulate information will be constructed. For example, a solid-state quantum computer has been proposed that encodes information in the nuclear spin of shallow arrays of single 31P atoms (quantum bits or qubits) in a matrix of pure silicon. Construction of these devices presents formidable challenges. One strategy is

Changyi Yang; David N. Jamieson; Chris Pakes; Steven Prawer; Andrew Dzurak; Fay Stanley; Paul Spizziri; Linda Macks; Eric Gauja; Robert G. Clark

2003-01-01

219

Stem cell-based biological tooth repair and regeneration  

PubMed Central

Teeth exhibit limited repair in response to damage, and dental pulp stem cells probably provide a source of cells to replace those damaged and to facilitate repair. Stem cells in other parts of the tooth, such as the periodontal ligament and growing roots, play more dynamic roles in tooth function and development. Dental stem cells can be obtained with ease, making them an attractive source of autologous stem cells for use in restoring vital pulp tissue removed because of infection, in regeneration of periodontal ligament lost in periodontal disease, and for generation of complete or partial tooth structures to form biological implants. As dental stem cells share properties with mesenchymal stem cells, there is also considerable interest in their wider potential to treat disorders involving mesenchymal (or indeed non-mesenchymal) cell derivatives, such as in Parkinson's disease.

Volponi, Ana Angelova; Pang, Yvonne; Sharpe, Paul T.

2010-01-01

220

Dental Implant Surgery  

MedlinePLUS

Dental implant surgery Basics Multimedia Expert Answers Resources Reprints A single copy of this article may be reprinted for personal, noncommercial use only. Dental implant surgery By Mayo Clinic staff Original Article: http:// ...

221

Acute toxicological effects of ingested tooth whiteners in female rats.  

PubMed

Tooth whiteners are considered as cosmetic agents to be used for bleaching teeth. Since tooth whitener may be swallowed during the whitening procedure, studies were conducted to determine whether ingestion of tooth whitener containing carbamide peroxide resulted in toxic effects. Adult female rats were used, and vaginal smears were examined daily to determine whether the animals were ovulating. Following an overnight fast, a single bolus of a commercial tooth whitener (5 g of tooth whitener/kg fasting body weight) was administered by gavage. Control rats received de-ionized water. After 2 h, mean respirations per min of animals receiving the tooth whitener Quik Start (contains 35% carbamide peroxide) decreased from 169 to 55, and body temperature decreased from 38.4 to 34 degrees C. Other distress signs included: labored breathing, loss of righting reflex, partial eye closure, bloody urine, and incontinence. Three of 22 animals (3/22) died within 48 h, of gastric hemorrhaging. Eight/10 rats stopped ovulating. At necropsy 2 weeks post-dosing, 10/19 animals had grossly bloated stomachs, and mucosal necrosis was observed histologically in 3. Animals receiving White & Brite or Nu-Smile (containing 10 or 15% carbamide peroxide, respectively) exhibited similar but milder symptoms. The data indicate that ingestion of large doses of commercial preparations of tooth whiteners may be acutely toxic, sometimes fatal, to female laboratory rats. PMID:8360379

Cherry, D V; Bowers, D E; Thomas, L; Redmond, A F

1993-09-01

222

Investigation of an implantable dosimeter for single-point water equivalent path length verification in proton therapy  

PubMed Central

Purpose:In vivo range verification in proton therapy is highly desirable. A recent study suggested that it was feasible to use point dose measurement for in vivo beam range verification in proton therapy, provided that the spread-out Bragg peak dose distribution is delivered in a different and rather unconventional manner. In this work, the authors investigate the possibility of using a commercial implantable dosimeter with wireless reading for this particular application. Methods: The traditional proton treatment technique delivers all the Bragg peaks required for a SOBP field in a single sequence, producing a constant dose plateau across the target volume. As a result, a point dose measurement anywhere in the target volume will produce the same value, thus providing no information regarding the water equivalent path length to the point of measurement. However, the same constant dose distribution can be achieved by splitting the field into a complementary pair of subfields, producing two oppositely “sloped” depth-dose distributions, respectively. The ratio between the two distributions can be a sensitive function of depth and measuring this ratio at a point inside the target volume can provide the water equivalent path length to the dosimeter location. Two types of field splits were used in the experiment, one achieved by the technique of beam current modulation and the other by manipulating the location and width of the beam pulse relative to the range modulator track. Eight MOSFET-based implantable dosimeters at four different depths in a water tank were used to measure the dose ratios for these field pairs. A method was developed to correct the effect of the well-known LET dependence of the MOSFET detectors on the depth-dose distributions using the columnar recombination model. The LET-corrected dose ratios were used to derive the water equivalent path lengths to the dosimeter locations to be compared to physical measurements. Results: The implantable dosimeters measured the dose ratios with a reasonable relative uncertainty of 1%–3% at all depths, except when the ratio itself becomes very small. In total, 55% of the individual measurements reproduced the water equivalent path lengths to the dosimeters within 1 mm. For three dosimeters, the difference was consistently less than 1 mm. Half of the standard deviations over the repeated measurements were equal or less than 1 mm. Conclusions: With a single fitting parameter, the LET-correction method worked remarkably well for the MOSFET detectors. The overall results were very encouraging for a potential method of in vivo beam range verification with millimeter accuracy. This is sufficient accuracy to expand range of clinical applications in which the authors could use the distal fall off of the proton depth dose for tight margins.

Lu, Hsiao-Ming; Mann, Greg; Cascio, Ethan

2010-01-01

223

Investigation of an implantable dosimeter for single-point water equivalent path length verification in proton therapy  

SciTech Connect

Purpose: In vivo range verification in proton therapy is highly desirable. A recent study suggested that it was feasible to use point dose measurement for in vivo beam range verification in proton therapy, provided that the spread-out Bragg peak dose distribution is delivered in a different and rather unconventional manner. In this work, the authors investigate the possibility of using a commercial implantable dosimeter with wireless reading for this particular application. Methods: The traditional proton treatment technique delivers all the Bragg peaks required for a SOBP field in a single sequence, producing a constant dose plateau across the target volume. As a result, a point dose measurement anywhere in the target volume will produce the same value, thus providing no information regarding the water equivalent path length to the point of measurement. However, the same constant dose distribution can be achieved by splitting the field into a complementary pair of subfields, producing two oppositely ''sloped'' depth-dose distributions, respectively. The ratio between the two distributions can be a sensitive function of depth and measuring this ratio at a point inside the target volume can provide the water equivalent path length to the dosimeter location. Two types of field splits were used in the experiment, one achieved by the technique of beam current modulation and the other by manipulating the location and width of the beam pulse relative to the range modulator track. Eight MOSFET-based implantable dosimeters at four different depths in a water tank were used to measure the dose ratios for these field pairs. A method was developed to correct the effect of the well-known LET dependence of the MOSFET detectors on the depth-dose distributions using the columnar recombination model. The LET-corrected dose ratios were used to derive the water equivalent path lengths to the dosimeter locations to be compared to physical measurements. Results: The implantable dosimeters measured the dose ratios with a reasonable relative uncertainty of 1%-3% at all depths, except when the ratio itself becomes very small. In total, 55% of the individual measurements reproduced the water equivalent path lengths to the dosimeters within 1 mm. For three dosimeters, the difference was consistently less than 1 mm. Half of the standard deviations over the repeated measurements were equal or less than 1 mm. Conclusions: With a single fitting parameter, the LET-correction method worked remarkably well for the MOSFET detectors. The overall results were very encouraging for a potential method of in vivo beam range verification with millimeter accuracy. This is sufficient accuracy to expand range of clinical applications in which the authors could use the distal fall off of the proton depth dose for tight margins.

Lu, Hsiao-Ming; Mann, Greg; Cascio, Ethan [Francis H. Burr Proton Therapy Center, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Sicel Technologies, Inc., Morrisville, North Carolina 27560 (United States); Francis H. Burr Proton Therapy Center, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)

2010-11-15

224

Tooth regeneration: a revolution in stomatology and evolution in regenerative medicine  

PubMed Central

A tooth is a complex biological organ and consists of multiple tissues including the enamel, dentin, cementum and pulp. Tooth loss is the most common organ failure. Can a tooth be regenerated? Can adult stem cells be orchestrated to regenerate tooth structures such as the enamel, dentin, cementum and dental pulp, or even an entire tooth? If not, what are the therapeutically viable sources of stem cells for tooth regeneration? Do stem cells necessarily need to be taken out of the body, and manipulated ex vivo before they are transplanted for tooth regeneration? How can regenerated teeth be economically competitive with dental implants? Would it be possible to make regenerated teeth affordable by a large segment of the population worldwide? This review article explores existing and visionary approaches that address some of the above-mentioned questions. Tooth regeneration represents a revolution in stomatology as a shift in the paradigm from repair to regeneration: repair is by metal or artificial materials whereas regeneration is by biological restoration. Tooth regeneration is an extension of the concepts in the broad field of regenerative medicine to restore a tissue defect to its original form and function by biological substitutes.

Yildirim, Sibel; Fu, Susan Y; Kim, Keith; Zhou, Hong; Lee, Chang Hun; Li, Ang; Kim, Sahng Gyoon; Wang, Shuang; Mao, Jeremy J

2011-01-01

225

Aesthetic analysis of an implant-supported denture at the cleft area.  

PubMed

Objective : To evaluate the aesthetics of an implant-supported denture at the cleft area, comparing the peri-implant tissues and prosthetic crown with the contralateral tooth. Settings : Hospital for Rehabilitation of Craniofacial Anomalies, Bauru, São Paolo, Brazil. Patients : A total of 39 individuals of both genders, with complete unilateral cleft lip and palate, who received secondary alveolar bone graft and were rehabilitated with single implant-supported dentures at the area of the missing maxillary lateral incisor after completion of orthodontic treatment. Interventions : The following parameters were analyzed in follow-up sessions: length and width of prosthetic crown and contralateral tooth, characteristics of implants, filling of interproximal space by the papilla, and smile height of the patients. Results : The implant-supported prosthetic crowns were longer than the contralateral tooth (p < .001). Among the 78 papillae analyzed, 29 (37.17%) received a score of 3; 32 (41.02%) papillae had a score of 2; and 17 (21.79%) received a score of 1. Concerning the smile height, among the 39 patients analyzed, 23 (56.41%) had a medium smile, 15 (38.46%) had a high smile, and two (5.12%) presented a low smile. Conclusion : The use of dental implants to rehabilitate the edentulous cleft area is an excellent option. However, adequate evaluation of the bone quantity and quality, positioning and shape of adjacent teeth, smile height, and patient expectations should be considered to achieve success and avoid aesthetic deformities such as elongated teeth and absence of gingival papillae. PMID:22616760

Filho, Jorge Francisco Fiamengui; de Almeida, Ana Lúcia Pompéia Fraga

2012-05-23

226

Tooth cleaning device  

US Patent & Trademark Office Database

There is disclosed a tooth cleaning device especially designed and adapted for home use by the general public. The device employs an electric motor coupled by a direct gear drive to a shaft to which may be attached a variety of cleaning, polishing and massaging tips. The housing of the device is shaped to fit in the palm of the hand and is provided with an easily accessible switch. The device is so designed that it cannot be used to reach areas of the teeth and gums that must be treated professionally.

1979-12-25

227

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

228

OHRQoL, masticatory performance and crestal bone loss with single-implant, magnet-retained mandibular overdentures with conventional and shortened dental arch.  

PubMed

PURPOSE: The aim of this study was to assess the use of single implant-supported, magnet-retained mandibular overdentures to improve the oral health-related quality of life (OHRQoL) and masticatory performance of patients wearing conventional complete dentures. The study also aimed at comparing the OHRQoL, masticatory performance, and crestal bone loss with two different types of overdenture prosthesis. MATERIALS AND METHODS: Ten completely edentulous patients with atrophic mandibular residual alveolar ridges and having difficulty coping with technically adequate mandibular dentures were selected for implant-supported overdentures (ISOD). To assess the success of the implant fixture clinically, a crossover study design was followed, and the patients were divided into two groups. Group A received ISOD with conventional complete dental arch, and group B received ISOD with a shortened dental arch for the first 3 months and vice versa for the next 3 months. The OHRQoL was measured with the OHIP-49 questionnaire, and masticatory performance was assessed with the sieve method using peanuts as test food. Peri-apical radiographs were taken to evaluate the crestal bone loss. RESULTS: A significant improvement was seen both subjectively and objectively when conventional complete dentures were modified to implant-supported prosthesis. When comparing the implant overdenture prosthesis, patients were more satisfied with conventional arch than with the shortened dental arch. In the first 3 months following implant placement, less bone loss was seen with the shortened dental arch overdenture (P < 0.05). CONCLUSION: Single implant-supported, magnet-retained mandibular overdentures significantly improve the OHRQoL of completely edentulous patients. PMID:23331716

Grover, Manita; Vaidyanathan, Anand Kumar; Veeravalli, Padmanabhan Thallam

2013-01-21

229

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

230

Direct Localization of Subthalamic Nucleus Supplemented by Single-Track Electrophysiological Guidance in Deep Brain Stimulation Lead Implantation: Techniques and Clinical Results  

Microsoft Academic Search

Background\\/Aims: In subthalamic nucleus (STN) deep brain stimulation (DBS) lead implantation, it is still controversial whether it is more appropriate to employ indirect or direct methods in magnetic resonance imaging (MRI)-based tentative targeting and to select single- or multiple-track recording in electrophysiological definitive targeting. The efficacy of single-track electrophysiological recording through direct targeting was compared with the conventional indirect targeting

Yu Koike; Fumio Shima; Akira Nakamizo; Yasushi Miyagi

2008-01-01

231

Simulation of orthodontic tooth movements  

Microsoft Academic Search

Orthodontic tooth movements are based on the ability of bone to react to mechanical stresses with the apposition and resorption of alveolar bone. Currently, the underlying biophysical, biochemical, and cellular processes are the subject of numerous studies. At present, however, an analytical description of orthodontic tooth movements including all components of the processes involved seems to be impossible. It was

Christoph Bourauel; Dieter Freudenreich; Dirk Vollmer; Dagmar Kobe; Dieter Drescher; Andreas Jäger

1999-01-01

232

Treating sensitivity during tooth whitening.  

PubMed

The most common side effect of tooth whitening is tooth sensitivity. There are a number of materials and techniques for reducing sensitivity. This article focuses on potassium nitrate applied either by brushing before initiating whitening or by application via a tray during whitening to reduce sensitivity. A detailed step-by-step procedure for managing hypersensitive patients is described. PMID:17039676

Haywood, Van B

2005-09-01

233

Clinical and Radiographic Evaluation of Br?nemark Implants with an Anodized Surface following Seven-to-Eight Years of Functional Loading  

PubMed Central

The aim of this study was to evaluate the clinical and radiographic long-term outcomes of dental implants with an anodized TiUnite surface, placed in routine clinical practice. Two clinical centers participated in the study. One hundred and seven implants (80 in the maxilla and 27 in the mandible) in 52 patients were followed in the long term. Both one- and two-stage techniques were used for 38 and 69 implants, respectively. Thirty-eight single tooth restorations and 22 fixed partial prostheses were delivered, according to a delayed loading protocol, within 4 to 12 months since implant placement. All implants were stable at insertion and at the long-term follow-up visit, which occurred between 7 and 8 years of functional loading. The mean followup was 7.33 ± 0.47 years. The mean marginal bone level change at the long-term followup as compared to baseline was 1.49 ± 1.03?mm. No implant failure occurred. Healthy peri-implant mucosa was found around 95% of implants, whereas 91% of implants showed no visible plaque at the implant surfaces at the long-term followup. The study showed that dental implants with the TiUnite anodized surface demonstrate excellent long-term clinical and radiographic outcomes.

Gelb, David; McAllister, Bradley; Nummikoski, Pirkka; Del Fabbro, Massimo

2013-01-01

234

Management of peri-implantitis  

PubMed Central

Peri-implantitis is a site-specific infectious disease that causes an inflammatory process in soft tissues, and bone loss around an osseointegrated implant in function. The etiology of the implant infection is conditioned by the status of the tissue surrounding the implant, implant design, degree of roughness, external morphology, and excessive mechanical load. The microorganisms most commonly associated with implant failure are spirochetes and mobile forms of Gram-negative anaerobes, unless the origin is the result of simple mechanical overload. Diagnosis is based on changes of color in the gingiva, bleeding and probing depth of peri-implant pockets, suppuration, X-ray, and gradual loss of bone height around the tooth. Treatment will differ depending upon whether it is a case of peri-implant mucositis or peri-implantitis. The management of implant infection should be focused on the control of infection, the detoxification of the implant surface, and regeneration of the alveolar bone. This review article deals with the various treatment options in the management of peri-implantitis. The article also gives a brief description of the etiopathogenesis, clinical features, and diagnosis of peri-implantitis.

Prathapachandran, Jayachandran; Suresh, Neethu

2012-01-01

235

Bilateral fusion of mandibular second premolar and supernumerary tooth: A rare case report  

PubMed Central

Fusion is the union of two normally separated tooth germs resulting in the formation of a single large tooth. The prevalence of this anomaly is less than 1% and most common in the primary dentition, in the incisor-canine region. Fusions are almost always unilateral, but few cases of bilateral fusions have been reported. The purpose of this article is to report a rare case of bilateral fusion of mandibular second premolar with supernumerary tooth.

Muthukumar, R Sathish; Arunkumar, Sandhya; Sadasiva, Kadandale

2012-01-01

236

Bilateral fusion of mandibular second premolar and supernumerary tooth: A rare case report.  

PubMed

Fusion is the union of two normally separated tooth germs resulting in the formation of a single large tooth. The prevalence of this anomaly is less than 1% and most common in the primary dentition, in the incisor-canine region. Fusions are almost always unilateral, but few cases of bilateral fusions have been reported. The purpose of this article is to report a rare case of bilateral fusion of mandibular second premolar with supernumerary tooth. PMID:22434949

Muthukumar, R Sathish; Arunkumar, Sandhya; Sadasiva, Kadandale

2012-01-01

237

Cochlear Implants  

MedlinePLUS

... Medical Devices Products and Medical Procedures Implants and Prosthetics - Section Contents Menu Products and Medical Procedures Implants and Prosthetics Cochlear Implants What is a Cochlear Implant? Benefits ...

238

Functional tooth restoration by allogeneic mesenchymal stem cell-based bio-root regeneration in swine.  

PubMed

Our previous proof-of-concept study showed the feasibility of regenerating the dental stem cell-based bioengineered tooth root (bio-root) structure in a large animal model. Here, we used allogeneic dental mesenchymal stem cells to regenerate bio-root, and then installed a crown on the bio-root to restore tooth function. A root shape hydroxyapatite tricalcium phosphate scaffold containing dental pulp stem cells was covered by a Vc-induced periodontal ligament stem cell sheet and implanted into a newly generated jaw bone implant socket. Six months after implantation, a prefabricated porcelain crown was cemented to the implant and subjected to tooth function. Clinical, radiological, histological, ultrastructural, systemic immunological evaluations and mechanical properties were analyzed for dynamic changes in the bio-root structure. The regenerated bio-root exhibited characteristics of a normal tooth after 6 months of use, including dentinal tubule-like and functional periodontal ligament-like structures. No immunological response to the bio-roots was observed. We developed a standard stem cell procedure for bio-root regeneration to restore adult tooth function. This study is the first to successfully regenerate a functional bio-root structure for artificial crown restoration by using allogeneic dental stem cells and Vc-induced cell sheet, and assess the recipient immune response in a preclinical model. PMID:23363023

Wei, Fulan; Song, Tieli; Ding, Gang; Xu, Junji; Liu, Yi; Liu, Dayong; Fan, Zhipeng; Zhang, Chunmei; Shi, Songtao; Wang, Songlin

2013-03-15

239

Evaluation of Carbon Interstitial in C-ion Implanted ZnO Bulk Single Crystals by a Nuclear Reaction Analysis Study: An Origin of Low Resistivity  

NASA Astrophysics Data System (ADS)

Nuclear reaction analysis (NRA) of carbon-implanted ZnO bulk single crystals (carbon concentration: 1.5×1020 cm-3), in conjunction with the channeling technique, using the 12C(d,p)13C and 16O(d,p)17O reactions shows the presence of the interstitial carbon (Ci) and the occupancy of substitute sites of oxygen atoms. These results suggest that the variation in resistivity from the order of 104 ?cm (for un-implanted samples) to that of 10 ?cm (for as-implanted ones) is attributed to the Ci and/or its complex defects, which would act as a shallow donor in ZnO.

Izawa, Y.; Matsumoto, K.; Oga, T.; Kuriyama, K.; Kushida, K.; Kinomura, A.

2011-12-01

240

Hemisection of a fused tooth.  

PubMed

Fusion is a developmental anomaly which occurs due to a union of 1 or more adjacent teeth during morphodifferentiation of the dental germs. The present case report presents the hemisection of a maxillary central incisor fused with a supernumerary tooth. A 10-year-old boy was referred to clinic with the chief complaint of the presence of a large anterior tooth. Intraoral and radiographic investigations indicated fusion between the left central incisor and a supernumerary tooth. The fused tooth was separated with a diamond bur, and the supernumerary tooth was extracted. The left central incisor was restored with composite resin and the diastema between the maxillary central incisors was closed with orthodontic treatment. The left central incisor was still healthy after a follow-up examination period of 24 months. An ideal overjet and overbite relation was achieved at the end of the orthodontic treatment. Hemisection can be considered as an appropriate treatment alternative for a permanent tooth fused with a supernumerary tooth. PMID:17656128

Cetinbas, Tugba; Halil, Suleyman; Akcam, Mehmet Okan; Sari, Saziye; Cetiner, Serap

2007-07-25

241

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

242

Gold nanoparticle fabrication in single crystal SiO2 by MeV Au ion implantation and subsequent thermal annealing  

NASA Astrophysics Data System (ADS)

Gold nanoparticles were fabricated by ion implantation and subsequent high temperature annealing. 3.0MeV Au+ ions were implanted into single crystalline c-plane (0001) hexagonal SiO2 at fluences below the threshold for spontaneous cluster formation, from 1014ions/cm2 to 2x1016ions/cm2. The dose dependence, high temperature annealing effect and optical properties were studied. The typical optical absorption band of 520nm is not found prior to heat treatment for all implanted samples. By sequential heat treatment at different temperatures, we have found that the optical absorption is critically dependent on annealing temperature. After annealing at 1000 degC for 5h, the samples implanted at fluences above 1x1016ions/cm2 display optical absorption bands peaked at 2.37eV (523nm) which is characteristic of surface plasmon resonance of gold nanoparticles. The average particle radius of Au colloid particles is estimated to be about 4.2nm. RBS/Channeling analyses show the implanted Au to have the Gaussian profiles both before and after sequential annealing at different temperatures, and that the ion range is in a good agreement with the prediction from TRIM calculation.

Dai, Zhongning; Yamamoto, S.; Narumi, K.; Miyashita, A.; Naramoto, H.

1999-01-01

243

Charcot-Marie-Tooth Disease  

MedlinePLUS

... expectancy. What causes Charcot-Marie-Tooth disease? A nerve cell communicates information to distant targets by sending electrical ... Without an intact axon and myelin sheath, peripheral nerve cells are unable to activate target muscles or relay ...

244

The effect of estrogen administration during early pregnancy upon the survival of single implanted pig embryos.  

PubMed

In the present study, we investigated the influence of exogenous estrogen on embryo survival after transfer into prepubertal gilts in which estrus had been induced. In the first experiment, estrus was induced in prepubertal gilts by the administration of 1,000 IU of eCG and 750 IU of hCG every 72 h. Several blastocysts were recovered on d 6 (d 0 is the day of hCG administration), and 1 embryo was transferred to the tip of 1 side of the uterine horn on d 6 (Control). In treated groups, after embryo transfer, 5 mg of estradiol benzoate (EB) was administered on d 11 (EB5mg-1) or d 11, d 13, and d 15 (EB5mg-3) or d 11, 12, 13, 14, and 15 (EB5mg-5) or 20 mg of estradiol dipropionate (EDP) was administered on d 11 (EDP20mg-1) or d 11 and d 14 (EDP20mg-2). Autopsy examinations were performed on d 53 to 60. Although nontreated gilts did not become pregnant, gilts in each of the estradiol-treated groups became pregnant. The greatest pregnancy rate (77.8%, 7/9) was obtained with EDP20mg-2 (EDP20mg-2 > control: P < 0.05). In a second experiment, 1 blastocyst was transferred to prepubertal gilts and treated with EDP20mg-2. Pregnancy in recipient pigs was confirmed by ultrasonography, and pigs were allowed to farrow. Embryo survival rate was high on d 30 of pregnancy (75%, 9/12) but had a tendency (P = 0.0995) to decline from d 30 to delivery (33.3%, 4/12). In a third experiment, prepubertal gilts were administered 5 mg of EDP on d 11 (EDB5mg-1) and d 11 and d 14 (EDP5mg-2). Autopsy examinations were performed on d 53 to 58. Pseudopregnancy rate was high for EDP5mg-2 (63.6%, 7/11) compared with EDP5mg-1 (0%, 0/11; P < 0.05). In a fourth experiment, prepubertal gilts were transferred 1 blastocyst and treated with EDP5mg-2. Pregnancy was confirmed in recipient pigs by ultrasonography, and pigs were subsequently allowed to farrow. Embryo survival rate remained unchanged from d 30 of pregnancy to delivery (66.7%; 8/12). One piglet died from dystocia, and 1 suffered from deformity involving double-breasted hooves and died 6 d after birth. There was no difference (P > 0.05) in survival rate on d 30 of pregnancy and weaning (50%, 6/12). Body weight at birth and at weaning did not differ from that reported in previous studies. In conclusion, this study showed that EDP5mg-2 treatment during early pregnancy leads to full-term development of a single embryo. PMID:22829621

Kawarasaki, T; Enya, S; Otsu, Y

2012-07-24

245

The resolution of a periradicular lesion involving an implant.  

PubMed

Published reports claim that implants can fail from endodontic pathosis involving teeth adjacent to an implant, from preexisting bacteria in an extraction site that had a history of a tooth having a periradicular lesion, and even from an asymptomatic endodontically treated tooth with no clinical or radiographic evidence of pathosis. This report considers the support offered for an endodontic connection to implant failure, and it presents a case that conflicts with the premise that endodontic involvement causes implant failure. The diagnosis and treatment of a radiolucent lesion associated with an implant is described. Although initially interpreted as indicating a failing implant, the etiology of the radiolucency was a necrotic pulp in a maxillary lateral incisor with resorption. Nonsurgical endodontic treatment that combined Ca(OH)2 for interim treatment and mineral trioxide aggregate for final obturation completely resolved the periradicular lesion abutting the implant and successfully retained both the implant and the resorbed lateral incisor. PMID:18291288

Steiner, David R

2008-03-01

246

[Erosions of hard tooth substance].  

PubMed

Lemon juice was applied to intact and eroded tooth surfaces in vivo to demonstrate the development of erosions based on morphological changes. Under the influence of the fruit acid the protecting pellicles are removed and the enamel demonstrates the typical etch lesion with a honeycomb surface structure. In the dentin the acid works mainly on the peritubular area. Abrasive brushing techniques wear down the already damaged tooth surfaces. PMID:2630280

Noack, M J

1989-07-01

247

Therapeutic biomechanics concepts and clinical procedures to reduce implant loading. Part II: therapeutic differential loading.  

PubMed

Practical laboratory procedures were suggested in order to provide a modified occlusal anatomy to reduce implant loading. The concept of differential mobility caused by the flexion between a natural tooth/periodontal ligament interface with its supporting bone, compared with the stiffness of the implant/bone interface, was described. When individual tooth-supported and implant-supported prostheses coexist in the same arch, this differential mobility can shift the loading disproportionately from the natural teeth to the implants. A new concept of therapeutic differential loading is introduced and a clinical technique of differential occlusal adjustment is described to bring about a more favorable distribution of loading to all the supporting bone. Long-term natural tooth intrusion can cause implant overload. Therefore, it is suggested that periodic differential occlusal adjustment procedures be used to re-establish a long-term balance of loading between individual implant- and tooth-supported prostheses within the same arch. PMID:12498438

Weinberg, L A

2001-01-01

248

Signal processing for single tooth milling monitoring  

NASA Astrophysics Data System (ADS)

This paper describes the systematic development of a signal processing scheme aimed at monitoring tool wear development during a specific machining process. Classical processing schemes in the time and frequency domain are first used in order to obtain general signal characteristics. A signal generation model, using the concept of cyclostationary processes is then developed. A final processing scheme is then matched to extract specific features from the signal. Both the systematic approach, as well as the finally implemented scheme seem to offer viable approaches to the general task of monitoring high frequency vibrations in machine tools.

Braun, S.; Rotberg, J.; Lenz, E.

1987-04-01

249

Visible cathodoluminescence from Eu-implanted single- and polycrystal cBN annealed under high-temperature, high-pressure conditions  

Microsoft Academic Search

Red and red\\/blue cathodoluminescence in the temperature range 12 to 300 K was obtained from single- and polycrystal cubic boron nitride bulk samples implanted with europium and annealed under high-temperature, high-pressure conditions. All observed radiative intra-4f electron transitions of Eu3+ can be assigned to transitions starting from the 5D0 level of Eu3+. Additionally, radiative 4fN-15d-->4fN electron transitions related to Eu2+

Ulrich Vetter; Hans Hofsäss; Takashi Taniguchi

2004-01-01

250

Reconstruction of extraordinary refractive index profiles of optical planar waveguides with single or double modes fabricated by O 2+ ion implantation into lithium niobate  

Microsoft Academic Search

A method named intensity calculation method (ICM), which is based on beam propagation method (BPM) and image processing, was carried out to reconstruct the extraordinary refractive index profile (RIP) of single-mode planar waveguide in lithium niobate (LiNbO3), which was fabricated by multi-energy megaelectron-volt (MeV) O2+ ion implantation. In addition, it has been proved reasonable that the alternation of extraordinary refractive

Xiangzhi Liu; Fei Lu; Feng Chen; Yang Tan; Ruifeng Zhang; Hanping Liu; Lei Wang; Liangling Wang

2008-01-01

251

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

Microsoft Academic Search

X-ray absorption spectroscopy (XAS) has been applied to study the local structure around erbium ions implanted at 300keV (2×1016Er+ions\\/cm2) in LiNbO3 Y-cut single crystals annealed for 20h in air at 500 and 1100°C, respectively. For both samples, the data clearly reveal that Er3+ has neither formed metallic aggregates in the matrix nor precipitated in the form of the oxide. The

C. Mignotte

2001-01-01

252

Osseointegration of zirconia implants: an SEM observation of the bone-implant interface  

Microsoft Academic Search

BACKGROUND: The successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia (zirconium dioxide, ZrO2) has the potential to become a substitute for titanium as dental implant material. The present study aimed at investigating the osseointegration of zirconia implants with modified

Rita Depprich; Holger Zipprich; Michelle Ommerborn; Eduardo Mahn; Lydia Lammers; Jörg Handschel; Christian Naujoks; Hans-Peter Wiesmann; Norbert R Kübler; Ulrich Meyer

2008-01-01

253

Implanted Electrical Stimulation of the Trunk for Seated Postural Stability and Function after Cervical SCI: A Single Case Study  

PubMed Central

Objective(s) To explore and quantify the physical and functional effects of stabilizing the torso with electrical stimulation of the paralyzed hip and trunk musculature after motor complete tetraplegia. Design Single-subject case study with repeated measures and concurrent controls. Setting Academic outpatient rehabilitation center. Participants Forty-four year old male with C4 ASIA A tetraplegia 20 years post spinal cord injury. Intervention A surgically implanted multichannel pulse generator and intramuscular stimulating electrodes to activate lumbar erector spinae, quadratus lumborum, and gluteus maximus muscles bilaterally. Main Outcome Measure(s) Outcomes assessed with and without stimulation included a) spinal alignment and pelvic orientation, b) pulmonary function and ventilatory volumes, c) forward bimanual reaching distance, d) seated stability and resistance to externally applied disturbances, e) maximal force and speed of rowing-like movements, and the ability to f) independently return to an erect seated position from full forward or lateral flexion, and g) roll in bed without assistance. Results Stimulation improved spinal convexity and kyphosis by 26° and 21°, reduced posterior pelvic tilt by 11°; increased forced expiratory volume and vital capacity by 10% and 22%, and improved forward reach by > 7 cm. Average resistance to sagittal disturbances increased by > 40% (p<0.002) and mean force exerted during underhanded pulling more than doubled (p=0.014) with stimulation. Restoration of upright sitting in both sagittal and coronal planes and bed turning were made possible through appropriately timed activation of the hip and trunk muscles. Conclusions A neuroprosthesis for controlling the paralyzed torso can positively impact spinal alignment, seated posture, pulmonary function, trunk stability, and reach. Stimulation of hip and trunk muscles can improve performance of activities of daily living as well as enable independent wheelchair and bed mobility.

Triolo, Ronald J.; Boggs, Lisa; Miller, Michael E.; Nemunaitis, Gregory; Nagy, Jennifer; Bailey, Stephanie Nogan

2008-01-01

254

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

2012-02-28

255

X-ray microbeam probing of elastic strains in patterned He+ implanted single-crystal LiNbO3  

NASA Astrophysics Data System (ADS)

X-ray microprobing is used to investigate buried elastic strain resulting from deep He+ implantantion in LiNbO3. The implantation regions are defined lithographically and strain fields mapped with spatial- and energy-resolved x-ray microdiffraction to characterize the resulting structures. The structurally modified regions are found to retain their lateral lithographic definition, with the buried implantation being in strong compression.

Djukic, Djordje; Roth, Ryan M.; Osgood, R. M.; Evans-Lutterodt, Kenneth; Bakhru, Hassaram; Bakhru, Sasha; Welch, David

2007-09-01

256

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

257

Effects of echistatin and an RGD peptide on orthodontic tooth movement.  

PubMed

We tested whether orthodontic tooth movement (OTM) could be blocked by local administration of echistatin or an arginine-glycine-aspartic acid (RGD) peptide, agents known to perturb bone remodeling, adjacent to maxillary molars in rats. These molecules were incorporated into ethylene-vinyl acetate (ELVAX), a non-biodegradable, sustained-release polymer. In vitro experiments showed that the echistatin and RGD peptide were released from ELVAX in active forms at levels sufficient to disrupt osteoclasts. Biotinylated RGD peptide was released from ELVAX into the PDL after surgical implantation. ELVAX loaded with either RGD peptide or echistatin and surgically implanted next to the maxillary molars inhibited orthodontic tooth movement (p < 0.01). The RGD peptide also reduced molar drift (p < 0.05). This study shows the feasibility of using ELVAX to deliver integrin inhibitors adjacent to teeth to limit local tooth movement in response to orthodontic forces. PMID:12939350

Dolce, C; Vakani, A; Archer, L; Morris-Wiman, J A; Holliday, L S

2003-09-01

258

Ion Implantation in Perovskite Type Ferroelectrics.  

National Technical Information Service (NTIS)

The object of this work was to study ion implantation in perovskite ferroelectrics and to investigate the conductive behavior of implanted layers. Implantation experiments were carried out on strontium titanate, barium titanate (single crystal and ceramic...

R. Gerson

1979-01-01

259

On the influence of low energy tantalum ion implantation on indentation fracture and hardness of ?-alumina single crystals  

NASA Astrophysics Data System (ADS)

The prismatic (1120) plane of sapphire was implanted with different fluences of tantalum ions of an energy of 60 keV. The continuous indentation test with different orientations of the Knoop indenter was applied to study the mechanical properties of the material. The crack/twin pattern observed in the vicinity of the indentation mark was found to be dependent on both Knoop indenter orientation and the implantation fluence. Ion implantation with increasing fluence lead to reduction of the crack size. A more ductile behaviour of the modified sapphire was observed. The analysis of the registered indentation load/depth curves on the basis of the recently developed energy principle of indentation allowed to discuss the differences in indentation behaviour of implanted and virgin crystals. An attempt to explain the different kinds of ``steps'' observed on the loading curves of the indentation test is undertaken. The observed effects which last to a considerably higher depth than the location of the implant are assigned to radiation induced amorphization and generation of compressive stresses.

Ensinger, W.; Nowak, R.

1993-06-01

260

Tooth Engineering: Searching for Dental Mesenchymal Cells Sources  

PubMed Central

The implantation of cultured re-associations between embryonic dental mesenchymal cells and epithelial cells from mouse molars at embryonic day 14 (ED14) allowed making full teeth with crown, root, periodontal ligament fibers, and bone. Although representing valuable tools to set up methodologies embryonic cells are not easily available. This work thus aimed to replace the embryonic cells by dental mesenchymal cell lines or cultured expanded embryonic cells, and to test their ability to mediate tooth development in vitro when re-associated with a competent dental epithelium. Histology, immunostaining and RT-PCR allowed getting complementary sets of results. Two different immortalized cell lines from ED18 dental mesenchyme failed in mediating tooth formation. The potentialities of embryonic dental mesenchymal cells decreased from ED14 to ED16 and were lost at ED18. This is likely related to a change in the mesenchymal cell phenotype and/or populations during development. Attempts to cultivate ED14 or ED16 embryonic dental mesenchymal cells prior to re-association led to the loss of their ability to support tooth development. This was accompanied by a down-regulation of Fgf3 transcription. Supplementation of the culture medium with FGF2 allowed restoring Fgf3 expression, but not the ability of mesenchymal cells to engage in tooth formation. Altogether, these observations suggest that a competent cell population exists in the dental mesenchyme at ED14, progressively decreases during development, and cannot as such be maintained in vitro. This study evidenced the need for specific conditions to maintain the ability of dental mesenchymal cells to initiate whole tooth formation, when re-associated with an odontogenic epithelium. Efforts to improve the culture conditions will have to be combined with attempts to characterize the competent cells within the dental mesenchyme.

Keller, Laetitia; Kuchler-Bopp, Sabine; Mendoza, Soledad Acuna; Poliard, Anne; Lesot, Herve

2011-01-01

261

p63 in tooth development.  

PubMed

Recent findings have shown that the development of teeth involves a complex sequence of molecular events in which the p53 family member p63 is involved. Indeed, mice lacking p63 do not have teeth and humans bearing mutations in p63 suffer developmental syndromes that affect tooth morphology and number. Several isoforms of p63 have been described: the use of two different promoters produces longer TAp63 isoforms, or shorter, 5' truncated isoforms known as ?Np63. The 3' end of primary transcripts is then subject to alternative splicing resulting in three additional isoforms: alpha (?), beta (?) and gamma (?). Tooth development relies mainly on the activity of the N-terminally truncated ?Np63 isoforms. Here we review the experimental evidence for the involvement of ?Np63 in tooth development through its ability to sustain the molecular signalling that orchestrates epithelial-mesenchymal interaction. PMID:21787761

Rufini, Alessandro; Barlattani, Alberto; Docimo, Raffaella; Velletri, Tania; Niklison-Chirou, Maria Victoria; Agostini, Massimiliano; Melino, Gerry

2011-07-20

262

21 CFR 872.3920 - Porcelain tooth.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3920 Porcelain tooth. (a) Identification. A porcelain tooth is a prefabricated device...

2013-04-01

263

Factors affecting the willingness to pay for implants: A study of patients in Riyadh, Saudi Arabia  

PubMed Central

Background: One of the factors that dissuade patients needing tooth replacement from choosing dental implants is the prohibitive cost. Willingness to pay (WTP) is a useful tool to determine the ideal cost of an expensive procedure. Aim: The aim of this study was to study the factors that influence the willingness to pay (WTP) among patients attending a private clinic and compare them to those attending a government setup. Materials and Methods: A total of 100 patients (38 male, 62 female) who had one or more missing teeth were presented with different cost-benefit scenarios and then asked if they were willing to pay the median cost of a single implant in Riyadh city. The mean WTP price was compared using the one way-ANOVA, factors which could possibly influence patients’ WTP were grouped together in a Binomial logistic regression model. Results: Of the 100 individuals surveyed 67% said they would be willing to pay the median price for the placement of an implant. A comparison of socio-demographic factors showed that significant differences were found between gender, income groups and setting of the clinic in the mean WTP price of the patients (P < 0.05). We also found that there was a significant difference in the mean WTP price between groups with regard to the area of the missing tooth, the patients’ perception of their oral health and the their desire to want an implant (P < 0.05). Conclusion: The majority of the patients surveyed were willing to pay the median price for an implant. Willingness to pay (WTP) is a multifactorial variable which is significantly influenced by the income of the patient, the setting of the clinic and the gender; the most significant factor being the acceptability of the implant to the patient.

Al Garni, Bishi; Pani, Sharat Chandra; AlMaaz, Adel; Al Qeshtaini, Ehsan; Abu-Haimed, Hamad; Al Sharif, Khalid

2012-01-01

264

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.

Whitlock, John A; Richman, Joy M

2013-01-01

265

Immediate, non-submerged, root-analogue direct laser metal sintering (DLMS) implants: a 1-year prospective study on 15 patients.  

PubMed

This study evaluated the 1-year survival and success rate of root-analogue direct laser metal sintering (DLMS) implants, placed into the extraction sockets of 15 patients. DLMS is a technology which allows solids with complex geometry to be fabricated by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model; the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer-by-layer, the desired object. Cone-beam computed tomography (CBCT) acquisition and 3D image conversion, combined with the DLMS process, allow the fabrication of custom-made, root-analogue implants (RAIs). CBCT images of 15 non-restorable premolars (eight maxilla; seven mandible) were acquired and transformed into 3D models: from these, custom-made, root-analogue DLMS implants with integral abutment were fabricated. Immediately after tooth extraction, the RAIs were placed in the sockets and restored with a single crown. One year after implant placement, clinical and radiographic parameters were assessed: success criteria included absence of pain, suppuration, and exudation; absence of implant mobility and absence of continuous peri-implant radiolucency; distance between the implant shoulder and the first visible bone-to-implant contact <1.5 mm from initial surgery; and absence of prosthetic complications. At the 1-year follow-up, no implants were lost, for a survival rate of 100 %. All implants were stable, with no signs of infection. The good conditions of the peri-implant tissues were confirmed by the radiographic examination, with a mean DIB of 0.7 mm (±0.2). The possibility of fabricating custom-made, RAI DLMS implants opens new interesting horizons for immediate placement of dental implants. PMID:23494103

Mangano, Francesco Guido; De Franco, Michele; Caprioglio, Alberto; Macchi, Aldo; Piattelli, Adriano; Mangano, Carlo

2013-03-15

266

Clinical Management of Implant Prostheses in Patients with Bruxism  

PubMed Central

There is general agreement that excessive stress to the bone-implant interface may result in implant overload and failure. Early failure of the implant due to excessive loading occurs shortly after uncovering the implant. Excess load on a final restoration after successful implant integration can result in physical failure of the implant structure. Many clinicians believe that overload of dental implants is a risk factor for vertical peri-implant bone loss and/or may be detrimental for the suprastructure in implant prostheses. It has been documented that occlusal parafunction, such as, bruxism (tooth grinding and clenching) affects the outcome of implant prostheses, but there is no evidence for a causal relation between the failures and overload of dental implants. In spite of this lack of evidence, often metal restorations are preferred instead of porcelain for patients in whom bruxism is presumed on the basis of tooth wear. The purpose of this paper is to discuss the importance of the occlusal scheme used in implant restorations for implant longevity and to suggest a clinical approach and occlusal materials for implant prostheses in order to prevent complications related to bruxism.

Komiyama, Osamu; Lobbezoo, Frank; De Laat, Antoon; Iida, Takashi; Kitagawa, Tsuyoshi; Murakami, Hiroshi; Kato, Takao; Kawara, Misao

2012-01-01

267

Biological Aspects as a Rule for Single Implant Placement. The 3A-2B Rule: A Clinical Report.  

PubMed

For an implant restoration to be both esthetically and functionally successful, the prosthodontist must conduct a thorough treatment plan and complete a prosthesis design. The prosthodontist must carefully calculate the space needed for the restoration and soft tissue in the restoration process. The restoration and soft tissue are affected by the three-dimensional (3D) position of the implant, as the implant's depth determines the ideal length of the crown. When determining the 3D position of the implant, the clinician must consider the biological aspects required to ensure the restoration's biological integration with the patient's hard and soft tissues. The restoration must be the first component considered in the treatment plan. In addition, the clinician must understand that the distance between the cervical contour (of the planned restoration) and the level of the bone will dictate how the surgical and prosthetic treatment plan is enacted. In this report, a novel Radiographic Biological Ruler© (with biological information) was used to help facilitate the treatment plan's analysis. PMID:23551872

Rojas-Vizcaya, Fernando

2013-04-01

268

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

PubMed

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 beta-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 beta-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

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

2006-11-22

269

An alternative approach sequence to early implant placement and bone grafting over upper incisor traumatic loss in a malocclusion patient.  

PubMed

Abstract Oral rehabilitation following severe dental trauma often includes reconstruction of soft tissue and bony defects and orthodontic treatment to create an ideal three-dimensional position for implant placement. However, patients may decline time-consuming orthodontic treatment; moreover, delay in implant placement and orthodontic tooth movement may lead to ridge atrophy and changes in the ridge form and implant site, respectively, thus complicating implant placement.We present the management of a 38-year-old male with Class II dentoskeletal malocclusion, anterior crowding, deep bite (6.5 mm), increased overjet (5 mm), and traumatic loss of tooth 11 after an accident.The patient initially decided to undergo implant placement without orthodontic treatment, but he changed his mind after the implant placement. Enameloplasty of the maxillary anterior teeth, stripping for tooth contouring, and tooth extraction were performed to facilitate orthodontic treatment. Satisfactory esthetic and functional results were achieved despite violation of traditional protocols. PMID:23713415

Kuo, Tsu-Jen; Chang, Hsin-Ju; Hsieh, Yao-Dung; Wu, Chao Nan; Chen, Chi-Chong

2013-05-28

270

Comparative evaluation of bone-filled Polymethylmethacrylate implant, autograft fusion, and Polyetheretherketone cervical cage fusion for the treatment of single -level cervical disc disease.  

PubMed Central

Background: The objective of this study is to compare the clinical, functional, and radiological outcomes of using bone-filled Polymethylmethacrylate (PMMA) implant as an inexpensive alternative to Polyetheretherketone (PEEK) cage and Autologous bone graft (ABG) fusion after anterior cervical discectomy (ACD) for the treatment of single level cervical disc disease. Methods: 60 patients were prospectively randomized according to the material used for fusion after ACD into: 1) PMMA implant; 2) ABG; and 3) PEEK implant. The clinical outcomes were evaluated using Visual Analogue Scale (VAS), whereas the functional outcomes were evaluated using Odom's criteria. Radiological evaluations were also conducted using radiography and Computerized tomography (CT) scans and considered the following factors; bony fusion, cervical stability and disc space height (DSH) changes. The post- operative outcomes were evaluated at the following intervals; 2 weeks, 3 and 6 months. Results: The clinical outcomes demonstrated insignificant difference among the three treated groups throughout their follow up period. ABG group showed significant lower satisfactory functional outcomes (68.1%) compared to PMMA and PEEK groups (85% and 88.9%, respectively) at the 2-week post operative evaluation, but the ABG group showed closer functional outcomes to the PMMA and PEEK groups at the 3 and 6-month post operative evaluations. Despite the inferior bony fusion rates of the PMMA group (30%) compared to ABG group (86.3%) and PEEK group (77.7%) at the 6-month post operative evaluation, the clinical and functional outcomes were comparable. Conclusions: Bone-filled PMMA implant is a reliable treatment option; despite its inferior fusion rate at the 6-month postoperative evaluation, it still provides acceptable segmental stability, satisfactory clinical and functional outcomes that are comparable to ABG and PEEK grafting procedures.

Orief, Tamer; Ramadan, Ismael; Seddik, Zaki; Kamal, Marwan; Rahmany, Mohamed; Takayasu, Masakazu

2010-01-01

271

Alveolar ridge resorption after tooth extraction: A consequence of a fundamental principle of bone physiology  

PubMed Central

It is well established that tooth extraction is followed by a reduction of the buccolingual as well as the apicocoronal dimension of the alveolar ridge. Different measures have been taken to avoid this bone modelling process, such as immediate implant placement and bone grafting, but in most cases with disappointing results. One fundamental principle of bone physiology is the adaptation of bone mass and bone structure to the levels and frequencies of strain. In the present article, it is shown that the reduction of the alveolar ridge dimensions after tooth extraction is a natural consequence of this physiological principle.

Halldin, Anders

2012-01-01

272

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

273

Quantifying He-point defect interactions in Fe through coordinated experimental and modeling studies of He-ion implanted single-crystal Fe  

NASA Astrophysics Data System (ADS)

Understanding the effects of helium on the microstructural evolution and mechanical properties of structural materials are among the most challenging issues in fusion materials research. In this work, we combine thermal helium desorption spectroscopy (THDS) with positron annihilation spectroscopy (PAS) and a spatially dependent cluster dynamics model to investigate the energetics of helium-point defect interactions in helium-implanted single-crystal iron. The combination of modeling and thermal desorption measurements allows identification of the binding energies of small He-V clusters, the migration energy of single vacancy and possible mechanisms (e.g., shrinkage of He3V2 clusters) responsible for measured Helium desorption peaks, and the effect of impurities (e.g., carbon) on these values. Furthermore, the model predicts the depth dependence of the helium and helium-vacancy clusters as a function of time and temperature during the thermal desorption measurement. Here, we report the THDS measurement results as a function of He implantation energy from 10 to 40 keV at a fluence level of 1 × 1015 He/cm2, along with selected PAS measurements. The experimental results are compared to the modeling predictions to evaluate the extent to which self-consistent values of the He-point defect binding and interaction energies and diffusivities can explain the data.

Hu, Xunxiang; Xu, Donghua; Wirth, Brian D.

2013-11-01

274

Tunable Band-Stop Plasmonic Filter Based on Symmetrical Tooth-Shaped Waveguide Couples  

NASA Astrophysics Data System (ADS)

A simple plasmonic filter with symmetrical tooth-shaped waveguides is proposed and investigated by using finite element method. It is found that the structure with a single symmetrical tooth-shaped waveguide couple can realize a tunable band-stop filter. Attributed to cascaded symmetrical tooth-shaped waveguide couples, the structure can achieve a flat band-stop response with no intensity variation over the transmission spectrum. And the central wavelength of the stopband linearly increases with the simultaneous increasing of depths of waveguides. Moreover, reduced structure size can be achieved by controlling the dielectric constant of the medium.

Cui, Luna; Song, Gang; Yu, Li; Lang, Peiling; Xiao, Jinghua

2013-06-01

275

[Current terminology for tooth wear].  

PubMed

In general dental practice the "abrasion" diagnosis is universally used for the loss of any tooth structure irrespective of its etiology. The author's aim was to summarize and classify the types of non-caries-related tooth wear (i.e. attrition, abrasion and erosion) based on their etiology and clinical features. All dental practitioners should be aware of the criteria of differentiation and the principles of differential diagnoses because only the elimination of the etiologic factors can ensure permanent therapeutic effect. On he other hand dental practitioners should also be familiar with this field to be able to recognize the early symptoms of certain general diseases that can initially be diagnosed in he dental office. Besides the elimination of the causative factors other specialist should also be involved in the comprehensive treatment to provide long-term success and arrest the progression of the disease. PMID:12762145

Fejérdy, Pál

2003-04-01

276

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.

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

2010-01-01

277

Anatomically shaped tooth and periodontal regeneration by cell homing.  

PubMed

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-epsilon-caprolactone and hydroxyapatite with 200-microm-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

2010-05-06

278

Molecular Genetics of Supernumerary Tooth Formation  

PubMed Central

Summary Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/?(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering.

Wang, Xiu-Ping; Fan, Jiabing

2011-01-01

279

Prospective Single-Arm, Multi-Center Trial of a Patient-Specific Interpositional Knee Implant: Early Clinical Results  

PubMed Central

Background: The treatment of unicompartmental arthritis in younger patients is challenging. The aim of this study is to report final safety and efficacy analysis results for the iForma patient–specific interpositional device, which is designed for the treatment of isolated medial or lateral compartment arthritis of the knee. Methods: From June 2005 to June 2008 78 subjects (42 men, 36 women) received an iForma implant. The mean age was 53 years, the mean Body Mass Index 29.0. We surveyed the WOMAC scores, the visual analog pain scale and the Knee Society Scores. Results: The mean follow up was 16.4 months. The mean WOMAC knee scores increased from 48.3 before surgery to 71.3 after 24 months. A reduction in pain was achieved for all five pain measures using a standard visual analog scale (VAS). Knee Society Knee Score improved from 39.2 before to 61.9 24 month after surgery. The Knee Society Function Scores improved form preoperative 64.5 to 82.5 2 years postoperative. The preoperative range of motion could be restored. The overall revision rate was 24%. 15 implants were removed early, 4 knees were revised without implant removal. Conclusion: Within narrow indication of patients with unicompartmental disease, the iForma device can provide improvement in knee function and reduction in pain, however, with a significant higher risk of early revision compared to traditional arthroplasty. Respecting this limitation it may be an alternative option for arthritic patients with unicompartmental disease who have contraindications to High Tibial Osteotomy or are too young for knee replacement; the iForma device further has the distinct advantage of time and cost saving compared to those procedures.

Koeck, F.X; Luring, C; Goetz, J; Handel, M; Tingart, M; Grifka, J; Beckmann, J

2011-01-01

280

Tooth Size Variation Related to Age in Amboseli Baboons  

PubMed Central

We measured the molar size from a single population of wild baboons from Amboseli (Kenya), both females (n = 57) and males (n = 50). All the females were of known age; the males represented a mix of known-age individuals (n = 31) and individuals with ages estimated to within 2 years (n = 19). The results showed a significant reduction in the mesiodistal length of teeth in both sexes as a function of age. Overall patterns of age-related change in tooth size did not change whether we included or excluded the individuals of estimated age, but patterns of statistical significance changed as a result of changed sample sizes. Our results demonstrate that tooth length is directly related to age due to interproximal wearing caused by M2 and M3 compression loads. Dental studies in primates, including both fossil and extant species, are mostly based on specimens obtained from osteological collections of varying origins, for which the age at death of each individual in the sample is not known. Researchers should take into account the phenomenon of interproximal attrition leading to reduced tooth size when measuring tooth length for ondontometric purposes.

Galbany, Jordi; Dotras, Laia; Alberts, Susan C.; Perez-Perez, Alejandro

2011-01-01

281

Bending Load Capacity Enhancement Using an Asymmetric Tooth Profile  

Microsoft Academic Search

This research is to develop a new method to enhance the bending load capacity of gear tooth using asymmetric tooth profiles. For many power transmission devices operate in one direction, only one side of the tooth surfaces (the front of tooth) is in mesh. So the tooth is not necessary to be a symmetric form. The dimensions of the front

Gang Deng; Tsutomu Nakanishi; Katsumi Inoue

2003-01-01

282

Endodontic re-treatment or implants: a contemporary conundrum.  

PubMed

In recent years, dental implants have become a common alternative in dental care. Of course, not all patients present with clear-cut treatment needs. Treatment planning an endodontically treated tooth that may require re-treatment vs extracting that same tooth and placing an implant may be one such conundrum. Given the disparity between the implant and endodontic re-treatment literature and the relative paucity of data-based results for indications and contraindications of endosseous root-form implants vs endodontic re-treatment, treatment planning can become a complex task. This article presents a few criteria to consider when treatment planning endodontic re-treatment vs extraction and subsequent implant placement. Because treatment planning can become such a complex issue, using all the varied resources of the dental team is imperative. PMID:16494097

Wolcott, James; Meyers, John

2006-02-01

283

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

284

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

285

21 CFR 872.3590 - Preformed plastic denture tooth.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Preformed plastic denture tooth. 872.3590 Section...Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated...

2013-04-01

286

Transvenous removal of pacing and implantable cardiac defibrillating leads using single sheath mechanical dilatation and multiple venous approaches: high success rate and safety in more than 2000 leads  

PubMed Central

Aims The aim of the present study was to describe a 10 years single-centre experience in pacing and defibrillating leads removal using an effective and safe modified mechanical dilatation technique. Methods and results We developed a single mechanical dilating sheath extraction technique with multiple venous entry site approaches. We performed a venous entry site approach (VEA) in cases of exposed leads and an alternative transvenous femoral approach (TFA) combined with an internal transjugular approach (ITA) in the presence of very tight binding sites causing failure of VEA extraction or in cases of free-floating leads. We attempted to remove 2062 leads [1825 pacing and 237 implantable cardiac defibrillating (ICD) leads; 1989 exposed at the venous entry site and 73 free-floating] in 1193 consecutive patients. The VEA was effective in 1799 leads, the TFA in 28, and the ITA in 205; in the overall population, we completely removed 2032 leads (98.4%), partially removed 18 (0.9%), and failed to remove 12 leads (0.6%). Major complications were observed in eight patients (0.7%), causing three deaths (0.3%). Conclusion Mechanical single sheath extraction technique with multiple venous entry site approaches is effective, safe, and with a good cost effective profile for pacing and ICD leads removal.

Bongiorni, Maria Grazia; Soldati, Ezio; Zucchelli, Giulio; Di Cori, Andrea; Segreti, Luca; De Lucia, Raffaele; Solarino, Gianluca; Balbarini, Alberto; Marzilli, Mario; Mariani, Mario

2008-01-01

287

What do we do after an implant fails? A review of treatment alternatives for failed implants.  

PubMed

The problem of failed implants cannot be overlooked. The purpose of this paper is to explore treatment alternatives for failed implants and their strengths and shortcomings. A comprehensive literature search was performed using PubMed and a manual search. Only five studies were identified that explored treatment in sites where implants had failed. In all five studies, the treatment alternative tested was the placement of a new implant in the failed site. The overall survival rate for such implants ranged from 71% to 92.3%. Four other alternatives are also discussed in light of data derived from other studies on the survival of various treatment strategies. These include: a continuation of the original plan using the remaining implants, modification of treatment to a tooth-supported fixed partial denture (FPD) or to a hybrid tooth-implant? supported FPD, or modification to a removable prosthesis. The selection of an appropriate alternative for failed implants is complex and involves biologic, mechanical, and psychologic considerations along with financial aspects. This should be a team decision with the patient's opinion included. PMID:23820700

Machtei, Eli E

288

Intraoperative comparison of sequential-pulse and single-pulse defibrillation in candidates for automatic implantable defibrillators.  

PubMed

Sixteen survivors of cardiac arrest underwent intraoperative comparison of the effectiveness of sequential-pulse and single-pulse defibrillation. Defibrillation was tested alternately with the single-pulse or sequential-pulse technique 10 seconds into an episode of ventricular fibrillation that was induced with alternating current. The sequential-pulse defibrillation technique using truncated exponential pulses was performed with a right ventricular endocardial catheter and a left ventricular epicardial patch electrode. The first pulse was delivered between the right ventricular apical and the superior vena caval electrode on the right ventricular endocardial catheter. The second pulse was delivered between the right ventricular apical electrode and the left ventricular patch electrode 0.2 ms after termination of the first pulse. Single-pulse defibrillation was performed with a standard intracardiac defibrillation system in which a single truncated exponential pulse was delivered across 2 epicardial patch electrodes positioned over the anterolateral right ventricle and the posterolateral left ventricle. During defibrillation threshold determination, voltage and current waveforms were recorded and integrated to determine delivered energy. Average defibrillation threshold leading-edge voltage for the sequential pulse technique was 496 +/- 140 V, compared with 365 +/- 157 V for the single-pulse technique (p less than 0.005). Defibrillation threshold leading-edge current for the sequential-pulse technique was 6.0 +/- 2.3 A, compared with 10.6 +/- 5.1 A for the single-pulse method (p less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3630945

Bardy, G H; Stewart, R B; Ivey, T D; Graham, E L; Adhar, G C; Greene, H L

1987-09-01

289

Large Scale Study of Tooth Enamel.  

National Technical Information Service (NTIS)

Human tooth enamel contains traces of foreign elements. The presence of these elements is related to the history and the environment of the human body and can be considered as the signature of perturbations which occur during the growth of a tooth. A map ...

F. Bodart G. Deconninck M. T. Martin

1981-01-01

290

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

291

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

292

Regional odontodysplasia: a case of progressive tooth development.  

PubMed

Regional odontodysplasia (RO) is considered a relatively rare dental anomaly despite increasing numbers of case reports in recent years. It usually presents as a localized anomaly in tooth development affecting a few adjacent teeth in a single maxillary or mandibular quadrant. The purpose of this paper is to describe an uncommon case of regional odotodysplasia involving noncontiguous mandibular teeth, crossing the midline in a male patient, and showing progressive normalization of tooth anatomy over a period of 6 years. Typically, teeth affected with RO become pulpally involved early on and are either extracted or endodontically treated. Such reports of automatic normalization over time in RO is supportive of a more conservative treatment approach. PMID:22918107

Ganguly, R; Ramesh, A

293

Placing Dental Implants  

MedlinePLUS

Placing Dental Implants Before Placing an Implant Placing the Implants Complications from Surgery Implant Failure When you get implants, more ... Implant Most people are good candidates to get dental implants. You must have enough bone in your jaw ...

294

[Esthetic IMZ implant for a central incisor].  

PubMed

Replacement of a missing incisor with an osseo-integrated implant, presents a difficult prosthetic problem for the practitioner because of the obliqueness of the implant and its diameter smaller than the tooth to be reconstructed. Therefore, a topographic and aesthetic pre-estimation is highly desirable. The patient whose treatment is described hereafter, presents large diastemas permitting to set the missing tooth in several locations. The various options are simulated on a study model and recorded by a silicone or resin index. This index is cut out so that the implant site is clearly defined and it presents a guide rod indicating the direction of the alveolar bone. The optimal site is selected during the surgical procedure with the most favorable index depending on the residual bone. After the implant is released, the location impression, is taken using asymmetric transfer allowing a strict positioning of the implant's replica and its thread. In order to prevent the making of a triangular-shaped crown, a false transfixed core removable is built over the intramobile component of the IMZ as well as pa periodontal ring. The latter is independent and maintained by the intramobile component. It compensates the difference in diameter between the implant and the natural tooth to be reconstructed. Its finely polished but asymmetric internal aspect prevents the rotation of the device. The volume of this device is controlled by a silicone index made on the preestimation model. Both pieces are cast in gold and assembled on the implant with a positioning indes. Parallel proximal grooves increase the friction of the core and a ceramo-metal crown is built in the conventional fashion. It is temporally cemented, and periodically removed and cleansed. The absence of gingical sulcus provides an aesthetic result similar to a bridge component. PMID:2638613

Brabant, A; Lejuste, P; Andriessens, J

1989-12-01

295

A 5-year retrospective clinical study of the Dentium implants  

PubMed Central

PURPOSE The aim of this retrospective study was to evaluate cumulative survival rate (CSR) of Implantium implants followed for 5 years and association between risk factors and the CSR. MATERIALS AND METHODS A total of two hundred forty-nine Implantium Implants System (Dentium, Seoul, Korea) placed in ninety-five patients from 2004 to 2009 were investigated with several identified risk factors (sex, systemic disease, smoking, alchohol, reason of tooth loss, length, arch (maxilla or mandible), replace tooth type (incisor, canine, premolar or molar) Kennedy classification, prosthodontic type, prosthodontic design, opposite dentition, abutment type, occlusal material, occlusal unit, splint to tooth, cantilever, other surgery). Clinical examination (mobility, percussion, screw loosening, discomfort, etc.) and radiographic examination data were collected from patient records including all problems during follow-up period according to protocols described earlier. Life table analysis was undertaken to examine the CSR. Cox regression method was conducted to assess the association between potential risk factors and overall CSR. RESULTS Five of 249 implants were failed. Four of these were lost before loading. The 5-year implant cumulative survival rate was 97.37%. Cox regression analysis demonstrated a significant predictive association between overall CSR and systemic disease, smoking, reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The screw related complication was rare. Two abutment screw fractures were found. Another complications of prosthetic components were porcelain fracture, resin facing fracture and denture fracture (n=19). CONCLUSION The 5-year CSR of Implantium implants was 97.37%. Implant survival may be dependent upon systemic disease, smoking reason of tooth loss, arch, Kennedy classification and prosthodontic design (P<.05). The presence of systemic diseases and combination of other surgical procedures may be associated with increased implant failure.

Lee, Jeong-Yol; Park, Hyo-Jin; Kim, Jong-Eun; Choi, Yong-Geun; Kim, Young-Soo; Huh, Jung-Bo

2011-01-01

296

The tooth - a treasure chest of stem cells.  

PubMed

Mesenchymal stem cells can be obtained with ease from dental/oral tissue, making them an attractive source of autologous stem cells. They offer a biological solution for restoring damaged dental tissues such as vital pulp engineering, regeneration of periodontal ligament lost in periodontal disease, and for generation of complete or partial tooth structures to form biological implants. Dental mesenchymal stem cells share properties with mesenchymal stem cells from bone marrow and there is a considerable potential for these cells to be used in different stem-cell-based therapies, such as bone and muscle regeneration. In addition, their immunosuppressive-immunomodulatory properties make these cells a suitable source for treating immunodisorders like systematic lupus erythematosus. In addition, gingival tissue might also be a very good source of epithelial cells used in the treatment of severe ocular surface disorders. Being such an accessible source for different stem cells, the tooth and the attached gingival tissue (usually discarded in the clinics) represent an ideal source of autologous or allogeneic stem cells that can be used in the treatment of many clinical conditions in dentistry and medicine. PMID:24113958

Volponi, A A; Sharpe, P T

2013-10-11

297

Reconstruction of extraordinary refractive index profile of O 2+ ion-implanted LiNbO 3 single-mode channel waveguide based on beam propagation method and image processing  

Microsoft Academic Search

A method bases on beam propagation method and image processing is brought forward to reconstruct the extraordinary refractive index profile of the ion-implanted single-mode channel waveguide in lithium niobate. Channel waveguide is formed by O2+ ion implantation at three energies of (3.0, 3.6 and 4.5MeV) and respective doses of (1.8, 2.2 and 4.8)×1014ions\\/cm2 in vacuum at room temperature. Only one

Xiangzhi Liu; Fei Lu; Feng Chen; Ruifeng Zhang; Hanping Liu; Lei Wang; Gang Fu; Haisong Wang

2007-01-01

298

Spectroscopic investigations of carious tooth decay.  

PubMed

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) at 460.55nm, and calcium (3d3D-4f 3F0) at 452.55nm transitions for spectroscopic analysis. The spectroscopic observations in conjunction with discriminate analysis showed that calcium attached to the hydroxyapatite structure of the tooth was affected severely at the infected part of the tooth. The position-time plots generated from two-dimensional (2D) images conclusively showed a decrease in calcium concentration in the infected region of the irradiated tooth. Using the technique, we could distinguish between the healthy and carious parts of the tooth with significant accuracy. PMID:18396438

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

2008-04-08

299

Tooth bleaching with nonthermal atmospheric pressure plasma.  

PubMed

We demonstrated that room temperature plasma could be used for tooth bleaching. A nonthermal, atmospheric pressure, helium plasma jet device was developed to enhance the tooth bleaching effect of hydrogen peroxide (H(2)O(2)). All teeth were sectioned sagittally into halves, which were assigned randomly to either the experimental group or the control group. The experimental group was treated with H(2)O(2) (28%, 20 microL every 30 seconds) plus plasma (5 W) for 10 minutes; the control group was treated with H(2)O(2) alone for the same duration. Removal of the tooth surface protein was demonstrated by scanning electron microscopy images and Ponceau staining. Production of hydroxyl radicals (.OH) was measured by using electron spin resonance spin-trapping. Combining plasma and H(2)O(2) improved the bleaching efficacy by a factor of 3 compared with using H(2)O(2) alone. Tooth surface proteins were noticeably removed by plasma treatment. When a piece of tooth was added to a solution of H(2)O(2) as a catalyst, production of *OH after plasma treatment was 1.9 times greater than when using H(2)O(2) alone. We suggest that the improvement in tooth bleaching induced by plasma is due to the removal of tooth surface proteins and to increased *OH production. PMID:19345811

Lee, Hyun Woo; Kim, Gon Jun; Kim, Jae Moon; Park, Jeong Kil; Lee, Jae Koo; Kim, Gyoo Cheon

2009-04-01

300

Safety of multi-channel stimulation implants: a single blocking capacitor per channel is not sufficient after single-fault failure.  

PubMed

One reason given for placing capacitors in series with stimulation electrodes is that they prevent direct current flow and therefore tissue damage under fault conditions. We show that this is not true for multiplexed multi-channel stimulators with one capacitor per channel. A test bench of two stimulation channels, two stimulation tripoles and a saline bath was used to measure the direct current flowing through the electrodes under two different single fault conditions. The electrodes were passively discharged between stimulation pulses. For the particular condition used (16 mA, 1 ms stimulation pulse at 20 Hz with electrodes placed 5 cm apart), the current ranged from 38 to 326 ?A depending on the type of fault. The variation of the fault current with time, stimulation amplitude, stimulation frequency and distance between the electrodes is given. Possible additional methods to improve safety are discussed. PMID:22391946

Nonclercq, Antoine; Lonys, Laurent; Vanhoestenberghe, Anne; Demosthenous, Andreas; Donaldson, Nick

2012-03-06

301

Tooth-colored inlays: new cementation technique.  

PubMed

A new technique for tooth-colored inlay cementation is introduced. Dual-cure fully filled restorative resin Sono-Cem (ESPE America, Norristown, PA) was used to cement tooth-colored restoration. A specially designed wooden tip in the gently vibrating Profin handpiece (Dentatus USA, New York) may be considered an excellent instrument for cementing porcelain and composite inlays with Sono-Cem cement. Also, a wide variety of diamond/tungsten plated abrasive Lamineer tips in a Profin Handpiece may be used for tooth preparation as well as for finishing restorations. PMID:9515433

Zhukovsky, L; Settembrini, L; Epelboym, D

302

Cochlear Implants  

MedlinePLUS

... and sends them to different regions of the auditory nerve. An implant does not restore normal hearing. ... portions of the ear and directly stimulate the auditory nerve. Signals generated by the implant are sent ...

303

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.

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

2013-01-01

304

Histologic comparison of biologic width around teeth versus implants: The effect on bone preservation  

Microsoft Academic Search

istological analysis of the biological width surrounding primate teeth offers insights into why the blood supply is reduced after tooth extraction and implant placement. This occurs because of the reduction of ridge width and height. The reduction in blood supply tends to be exacerbated as development of a new biologic width after implant placement causes facial bone to be lost

Kazuto Makigusa DDS

2009-01-01

305

Implant Overdentures: A New Standard of Care for Edentulous Patients— Current Concepts and Techniques  

Microsoft Academic Search

While most implant-based treatment has histori- cally focused on fixed prosthetic tooth replacement, the multitude of benefits to the edentulous population from implant overdentures is overwhelming in terms of improved function, emotional stability, physical health, and esthetics. Although there still remains a lack of consistency in terms of techniques, prosthetic design, and attachment systems, these aspects have been proven less

ROBERT C. VO GEL

306

Generation of a Crowned Pinion Tooth Surface by a Plane.  

National Technical Information Service (NTIS)

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 co...

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

1988-01-01

307

Peri-implant squamous odontogenic tumor.  

PubMed

Squamous odontogenic tumor (SOT) is a benign, locally infiltrative intraosseous tumor composed of well-differentiated squamous epithelium in a fibrous stroma. It seems to derive from the epithelial rests of Malassez in the periodontal ligament space. It presents an odontogenic origin, involving both the upper and lower maxillary bone, mainly areas without teeth or connective tissue of the odontogenic cysts. Clinically, SOT could be asymptomatic (3 cases), notwithstanding it is mainly characterized by pain, swelling, and tooth/teeth mobility. The most typical presentation of SOT is a slowly growing endobony lesion arising within a single periodontal location. Frequent misdiagnosis concerns either ameloblastoma and squamous cell carcinoma and fibroma. Since its first description in 1975, less than 50 cases have been identified. In light of the few reported cases, there are no consistently recorded clinical and radiographic features of SOT, and there is no predictable sex or site predilection. Diagnosis is predicated on recognition of the histopathologic features of SOT to obviate possible misdiagnosis of malignancy or ameloblastoma.We report the first case of SOT that arose in the vicinity of an implant. Through a meticulous review of literature, we discuss current etiology, pathogenesis, and treatment. PMID:21586976

Agostini, Tommaso; Sacco, Roberto; Bertolai, Roberto; Acocella, Alessandro; Colafranceschi, Maurizio; Lazzeri, Davide

2011-05-01

308

Charcot-Marie-Tooth and Related Diseases  

MedlinePLUS

... brain sends an electrical signal to muscle-controlling nerve cells in your spinal cord, which then use the ... your leg, you feel it because pain-sensitive nerve cells there C harcot-Marie-Tooth disease (CMT) is ...

309

Quality of Life for Children with Cochlear Implants: Perceived Benefits and Problems and the Perception of Single Words and Emotional Sounds  

ERIC Educational Resources Information Center

|Purpose: This study examined children's self-reported quality of life with a cochlear implant as related to children's actual perceptions of speech and the emotional information conveyed by sound. Effects of age at amplification with hearing aids and fitting of cochlear implants on perceived quality of life were also investigated. Method: A…

Schorr, Efrat A.; Roth, Froma P.; Fox, Nathan A.

2009-01-01

310

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.

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

2011-01-01

311

Tooth uprighting or separating appliance  

US Patent & Trademark Office Database

A tooth uprighting or separating appliance for cooperating with a pair of adjacent teeth having opposed and closely spaced side surfaces comprises a first member adapted to be interposed into a space between the pair of teeth for bearing against one of the opposed side surfaces of one of the pair of teeth, a second member adapted to be interposed into the space between the pair of teeth for bearing against the side surface of the other of the pair of teeth, and spring means interconnecting the first and second members for biassing the first and second members away from each other and toward the respective opposed side surfaces of the pair of teeth to thereby separate the teeth from each other. Preferably, the first and second members are adapted to pierce gum tissue which is located between the pair of teeth to facilitate installation. The spring means may comprise an elongated wire member or a coil spring portion from which the first and second means extend. The first and second members may both extend from the same side of the spring means, or may extend from opposite sides thereof.

Wallshein; Melvin (Brooklyn, NY)

1981-03-17

312

[Unconventional transradicular implant placement to avoid invasive surgeries: toward a potential paradigm shift].  

PubMed

The authors had for aim to present a new minimally-invasive protocol to rehabilitate anterior maxillary edentulism due to an impacted tooth. The implant is placed without removing the impacted tooth, which intercepts the implant trajectory. The inclusion/exclusion criteria have not been defined yet but this protocol goes against the consensual concept that no implant surface other than implant-bone interface should be tolerated. New implant-tissue interfaces are created in addition to the usual one, but this does not seem to jeopardize the prognosis of implants. The risk analysis shows that there is a growing corpus of reliable clinical and histological data to support this unconventional protocol. The overall follow-up covers from a 6-month to an 8-year period. This protocol should be more broadly documented before it can be used routinely; nevertheless it suggests that some of the leading concepts in dental implantology may be revisited. PMID:22914256

Davarpanah, M; Szmukler-Moncler, S; Davarpanah, K; Rajzbaum, P; de Corbière, S; Capelle-Ouadah, N; Demurashvili, G

2012-08-19

313

Finite element modelling of low-speed femur reaming using reamers with irregular tooth spacing  

NASA Astrophysics Data System (ADS)

Reaming of the cancellous bone of the femur is performed in certain orthopaedic procedures, in order to accommodate insertion of implants such as intramedullary nails. In such processes, the reamers spin at a maximum of 250 rev/min resulting in low-frequency vibrations, which can result in the formation of multicornered holes or non-cylindrical holes. These non-cylindrical holes can lead to improper fixation, which increases healing duration. Simulation of low-speed reaming in the femur analogue was conducted by using a finite element model of the reamer with two different models for reamer blade loads: concentrated forces on the tool tip and distributed forces on the engagement length of the reamer. The model of the process is quasi-static in a characteristic form. The specific cutting pressure, an important parameter in the governing equation, was found experimentally for this purpose. The effects of reaming condition, reamer size, and irregular tooth spacing on stability were investigated. An optimum irregular tooth spacing for a common six-flute reamer, resulting in the most stable reaming process was proposed. Hole profiles and tool axis trajectory of the tool were simulated for both regular and optimum irregular tooth spacing cases. The improvements in the hole quality from using the proposed irregular tooth spacing; benefits of which include expedition of post-operative healing, were demonstrated through simulated three-dimensional hole profiles.

Towfighian, S.; Behdinan, K.; Papini, M.; Saghir, Z.; Zalzal, P.; de Beer, J.

2008-12-01

314

Biofilm and dental implant: The microbial link  

PubMed Central

Mouth provides a congenial environment for the growth of the microorganisms as compared to any other part of the human body by exhibiting an ideal nonshedding surface. Dental plaque happens to be a diverse community of the microorganisms found on the tooth surface. Periodontal disease and the peri-implant disease are specific infections that are originating from these resident microbial species when the balance between the host and the microbial pathogenicity gets disrupted. This review discusses the biofilms in relation to the peri-implant region, factors affecting its presence, and the associated treatment to manage this complex microbial colony. Search Methodology: Electronic search of the medline was done with the search words: Implants and biofilms/dental biofilm formation/microbiology at implant abutment interface/surface free energy/roughness and implant, periimplantitis/local drug delivery and dental implant. Hand search across the journals – clinical oral implant research, implant dentistry, journal of dental research, international journal of oral implantology, journal of prosthetic dentistry, perioodntology 2000, journal of periodontology were performed. The articles included in the review comprised of in vivo studies, in vivo (animal and human) studies, abstracts, review articles.

Dhir, Sangeeta

2013-01-01

315

Materials for endosseous dental implants.  

PubMed

The goal of placement of endosseous dental implants is to achieve osseointegration or biointegration of the bone with the implant. A wide variety of materials has been used for these implants, but only a few promote osseointegration and biointegration. Titanium and titanium alloy (Ti6A14V) have been the most widely used of these materials. The surface oxide of titanium appears to be central to the ability of this material to osseointegrate. The oxide limits dissolution of elements and promotes the deposition of biological molecules which allow bone to exist as close as 30 A to the surface of the implant. The details of the ultrastructure of the gap between the implant and bone remain undefined, and the consequences of elements which are released on the interface over time are not known. These areas of investigation are particularly important in defining the differences between commercially pure titanium implants and those made of titanium, aluminium and vanadium. The epithelial interface between the gingiva and titanium appears to contain many of the structural characteristics of the native tooth-gingiva interface, but details are still vague. The connective tissue interface with the titanium appears to be one of tightly fitting tissues rather than adhesion. Ceramic coatings appear to improve the ingrowth of bone and promote chemical integration of the implant with the bone. The characteristics of these coatings are complex and affect the bony response, but the mechanisms remain obscure. The degradation of the coatings is an issue of particular controversy. Progress in dental implantology is likely to continue as the interface between the material and bone is more clearly understood, and biological molecules and artificial tissues are developed. PMID:8850057

Wataha, J C

1996-02-01

316

Management of fractured implant case using loop connector fixed partial denture.  

PubMed

Dental implants treatment have become a common modality of treatment nowadays for the replacement of missing tooth/teeth, but there have been failures due to a number of reasons; one of the rare problems is the fracture of the dental implants fixture. It is of prime importance to understand the type/system of the implant to be placed in a site and the amount and direction of occlusal forces incurred after the loading of prosthesis. PMID:23709559

Yadav, Ashish; Gupta, Aratee; Tandan, Amrit; Kumar, Sulabh

2013-05-24

317

Formation of single-crystal CoSi buffer layers on Si (100) substrates by high dose Co ion implantation for the deposition of YBaCuO{sub 7-x} thin films  

Microsoft Academic Search

High quality single-crystal CoSi layers have been successfully formed on Si (100) using low energy high dose Co ion implantation followed by subsequent annealing method as a buffer layer for the deposition of YBaCuO{sub 7-x} (YBCO) thin films. Rutherford backscattering spectrometry with channeling (RBS-C) measurements showed that CoSi layers after annealing at temperature between 850 and 950°C had a minimum

Y. Li; P. Seidel; F. Machalett; S. Linzen; F. Schmidl

1997-01-01

318

Damage, refractive index and near-field intensity profiles in a single-mode waveguide of LiNbO3 by 400 keV He ion implantation  

Microsoft Academic Search

We report on a single-mode waveguide in lithium niobate produced by 400 keV He ion implantation with a dose of 3 × 1016 ions cm-2 at liquid nitrogen temperature. Rutherford backscattering\\/channelling spectra have been measured in the waveguide before and after annealing and the damage profile has been extracted. The shape of the measured damage profile is similar to that

S. M. Zhang; X. H. Liu; X. F. Qin; K. M. Wang

2010-01-01

319

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

320

Photoluminescence Study of Germanium Implanted Gallium Arsenide.  

National Technical Information Service (NTIS)

The low temperature photoluminescence properties of Ge implanted Gallium Arsenide has been analyzed. Samples were singly implanted with Ge and As, and with Ge and Ga. The substrate used was semi-insulating Chromium-doped GaAs. All ions were implanted at r...

B. P. Thoma

1985-01-01

321

Ion implantation in perovskite type ferroelectrics  

Microsoft Academic Search

The object of this work was to study ion implantation in perovskite ferroelectrics and to investigate the conductive behavior of implanted layers. Implantation experiments were carried out on strontium titanate, barium titanate (single crystal and ceramic), titanium dioxide (rutile), lithium niobate, and lithium tantalate. Ion beams attempted were H(-), B(-), C(-), N(-), Fe(-), Ar(-), As(-), Ta(-), and Nb(--). In general

R. Gerson

1979-01-01

322

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

323

High Productivity Implantation ``PARTIAL IMPLANT''  

NASA Astrophysics Data System (ADS)

The patterned ion implantation ``PARTIAL IMPLANT'' has been developed as a productivity improvement tool. The Partial Implant can form several different ion dose areas on the wafer surface by controlling the speed of wafer moving and the stepwise rotation of twist axis. The Partial Implant system contains two implant methods. One method is ``DIVIDE PARTIAL IMPLANT,'' that is aimed at reducing the consumption of the wafer. The Divide Partial Implant evenly divides dose area on one wafer surface into two or three different dose part. Any dose can be selected in each area. So the consumption of the wafer for experimental implantation can be reduced. The second method is ``RING PARTIAL IMPLANT'' that is aimed at improving yield by correcting electrical characteristic of devices. The Ring Partial Implant can form concentric ion dose areas. The dose of wafer external area can be selected to be within plus or minus 30% of dose of wafer central area. So the electrical characteristic of devices can be corrected by controlling dose at edge side on the wafer.

Hino, Masayoshi; Miyamoto, Naoki; Sakai, Shigeki; Matsumoto, Takao

2008-11-01

324

Interim endodontic therapy for alveolar socket bone regeneration of infected hopeless teeth prior to implant therapy.  

PubMed

The immediate placement of implants in the fresh extraction sockets of infected teeth with periradicular and periapical lesions is contraindicated because of both the infection and the loss of architecture required for proper implant placement. There are 4 approaches for implant replacement of a hopeless tooth with lesions: (1) extraction and delayed implant placement; (2) extraction, debridement, guided bone regeneration (GBR), guided tissue regeneration (GTR), and delayed implant placement; (3) extraction, intrasocket debridement, and immediate implant placement; or (4) extraction, debridement, GBR, GTR, and simultaneous implant placement. The extraction of such hopeless teeth often results in large bone and soft tissue defects that are difficult to repair. This article introduces an alternative approach: interim endodontic implant site preparation, defined as a transitional, surgical, or nonsurgical endodontic treatment to regenerate the hopeless tooth bone defects and prepare the site for proper implant placement. This article describes 3 distinct interim endodontic protocols used to manage 5 patients, all of whom had severely infected hopeless teeth with large lesions and were treatment planned for implant replacement: the first, interim nonsurgical endodontic treatment to restore the normal anatomy of the infected hopeless tooth; the second, interim surgical endodontics on the hopeless tooth with preexisting endodontic treatment to regenerate apical bone for primary implant stability, thus avoiding the involvement of the maxillary sinus and other critical anatomic structures; and the third, interim surgical endodontics on the hopeless tooth with preexisting endodontic treatment to confine the size of the osseous defect and simplify the GBR and GTR procedures. The outcome of interim endodontic treatment on these 5 patients demonstrated that tooth extraction would have been a less predictable approach. The interim treatment changed the overall direction of the patients' dental care. When treated, these hopeless teeth served many preventive, biologic, and esthetic functions. The infections of the alveolar sockets were eliminated, the alveolar bone defects were repaired through normal bone regeneration, and sockets anatomies were maintained or restored. Furthermore, the patients were spared maxillary sinus surgery and the possible complications resulting from major GBR and GTR procedures. In summary, the interim treatment facilitated tooth extraction and immediate implant placement. PMID:20218869

Rass, Marwan Abou

2010-01-01

325

The unicorn and the narwhal: a tale of the tooth.  

PubMed

From as far back as the early Roman era, detailed descriptions and artistic images of the unicorn have been imagined. In Europe, the Mediterranean and the Far East, this creature became accepted as real. Although such an animal had never actually been seen, it was said to have the appearance of a horse, the beard and cloven hooves of a goat, the tail of a lion, and a single, spear-like horn protruding from the center of its forehead. The unicorn myth originated shortly after unidentified horn-like objects, from six to ten feet long, began to appear in ancient European marketplaces. Physicians quickly ascribed outlandish healing properties to these horns, pulverizing them for the treatment of various diseases. In 1638, a Danish zoologist challenged these claims and provided evidence that the so-called "unicorn horn" was actually the tusk (tooth) of the narwhal from the Arctic seas. However, his findings remained unheeded for the next 100 years. This paper explains how the myth of the unicorn and the purported powers contained within the substance of its magical horn evolved from the ages-old spoils of the Arctic fishing trade, where the narwhal was primarily speared for food and secondarily, for the export value of its ivory tusk. This unusually long, pointed and protruding single tooth, which breaks through the upper lip and the left jaw of each male narwhal, became a highly valuable commodity over the following centuries, due to its believed supernatural origins and curative qualities. PMID:22372187

Christen, Arden G; Christen, Joan A

2011-01-01

326

Age of an Indonesian Fossil Tooth Determined by Electron Paramagnetic Resonance  

SciTech Connect

The first fossil hominid tooth recovered during 1999 excavations from the Cisanca River region in West Java, Indonesia, was associated with a series of bovid teeth from a single individual that was recovered 190 cm beneath the hominid tooth. The age of the fossil bovid teeth was determined using electron paramagnetic resonance (EPR) analysis as part of an effort to bracket the age of the hominid tooth. The EPR-derived age of the bovid teeth is (5.16 {+-} 2.01) x 10{sup 5} years. However, the age estimate reported here is likely an underestimate of the actual age of deposition since evidence of heating was detected in the EPR spectra of the bovid teeth, and the heating may have caused a decrease in the intensity of EPR components on which the age calculation is based.

Bogard, JS

2004-04-07

327

Cochlear Implants  

MedlinePLUS

... studying large groups of children who were identified early with hearing loss and implanted with a cochlear implant. Knowledge from this research will shed light on the variables most related to improved speech and language acquisition as well as reading and higher academic performance ...

328

The use of definitive implant abutments for the fabrication of provisional crowns: a case series  

PubMed Central

Purpose The anterior region is a challenge for most clinicians to achieve optimal esthetics with dental implants. The provisional crown is a key factor in the success of obtaining pink esthetics around restorations with single implants, by soft tissue and inter-proximal papilla shaping. Provisional abutments bring additional costs and make the treatment more expensive. Since one of the aims of the clinician is to reduce costs and find more economic ways to raise patient satisfaction, this paper describes a practical method for chair-side fabrication of non-occlusal loaded provisional crowns used by the authors for several years successfully. Methods Twenty two patients (9 males, 13 females; mean age, 36,72 years) with one missing anterior tooth were treated by using the presented method. Metal definitive abutments instead of provisional abutments were used and provisional crowns were fabricated on the definitive abutments for all of the patients. The marginal fit was finished on a laboratory analogue and temporarily cemented to the abutments. The marginal adaptation of the crowns was evaluated radiographically. Results The patients were all satisfied with the final appearance and no complications occurred until the implants were loaded with permanent restorations. Conclusions The use of the definitive abutments for provisional crowns instead of provisional abutments reduces the costs and the same results can be obtained.

Bilhan, Hakan; Mumcu, Emre

2011-01-01

329

[Ectopic molar tooth in the maxillary sinus].  

PubMed

The development of intranasal ectopic teeth is rare. Although they are more commonly seen in the palate and maxillary sinus, they can also be found in the mandibular condyle, coronoid process, and nasal cavity. A 30-year-old male patient presented with a complaint of headache. Computed tomography of the paranasal sinuses showed a bony mass in the right maxillary sinus wall, 1 cm in size. He did not have any history of maxillofacial trauma or operation. The mass was removed via a Caldwell-Luc procedure. It looked like a tooth. Histopathologic diagnosis was made as ectopic molar tooth. The patient was asymptomatic two weeks after the operation. PMID:18187979

Altun, Hüseyin; Teker, Ay?enur Meriç; Ceran, Murat; Gedikli, Orhan

2007-01-01

330

Treatment imprudence leading to missed tooth fragment.  

PubMed

Traumatic dental injuries (TDI) represent one of the most common oral health problems in children and adolescents. Dental trauma requires a special consideration when it accompanies soft tissue lacerations. Tooth fragments occasionally penetrate into soft tissues and may cause severe complications. This article describes the case of a 12-year-old girl with a fractured tooth fragment embedded in the lower lip for 4 months, which went unnoticed at her primary health centre. This report highlights the importance of proper radiographic diagnosis along with clinical examination after trauma in order to prevent any future complications. PMID:23606390

Barua, Pranamee; Chaudhary, Seema; Kaur, Harsimran; Mallikarjuna, Rachappa

2013-04-19

331

Ectopic tooth in maxillary sinus: Case series  

PubMed Central

Ectopic eruption of a tooth within the dentate region of the jaws is often noticed in clinical practice and is well documented in the literature. But the ectopic eruption into the non dentate region is rare and scantly documented. The maxillary sinus is one such a non dentate region, apart from nasal septum, mandibular condyle, coronoid process and the palate, to accommodate such ectopic eruptions of teeth. Due to its rarity and lack of consensus over its management, the incidence deserves to be added to the literature and discussed. Early surgical intervention for removal of ectopic tooth along with enucleation of the associated cyst, if any, is the treatment of choice.

Ramanojam, Shandilya; Halli, Rajshekhar; Hebbale, Manjula; Bhardwaj, Smita

2013-01-01

332

Pulpal responses to cooling tooth temperatures.  

PubMed

This investigation measured pulpal blood flow and sensitivity to electrical stimulation as tooth temperatures were lowered. Dark rubber dams were placed on test teeth before placement of the cooling device in an attempt to shield gingival microcirculation. Laser Doppler flowmetry was used to measure pulp blood flow, whereas sensory thresholds were recorded simultaneously using an electric pulp tester. As tooth temperatures were lowered, the teeth became less responsive. Pulp blood flow also slowed, but did not completely stop. Results indicated that sensory thresholds were altered, and in some subjects, abolished, without total cessation of pulpal blood flow. PMID:11199731

Goodis, H E; Winthrop, V; White, J M

2000-05-01

333

Tooth discoloration induced by endodontic materials: a literature review.  

PubMed

It is common knowledge that materials used in endodontics may cause discoloration and thus impair the aesthetic outcome of the treated tooth. The purpose of this review is to summarise the existing knowledge on the discoloration potential of materials used for endodontic procedures. A comprehensive literature search covering the period from 1966 to 2011 was conducted on Pubmed and the Cochrane Library using different keyword combinations including 'tooth', 'colour', 'discoloration', 'staining', 'endodontic''root canal''sealer', 'dressing', 'medicament', 'obturation', 'filling', 'treatment', 'portland cement', 'MTA' and 'antibiotic paste'. Any relevant work published in the English language in peer-reviewed journals and presenting pertinent information related to the purpose of this overview was considered for inclusion. In addition, bibliographies of all relevant papers and previous review articles were hand searched and the reference lists from endodontic textbooks were also reviewed. Articles were excluded if an English abstract was unavailable, if only single clinical reports or conference reports were included, or if the topic was unrelated to the subject. Ten in-vitro studies, one randomized controlled trial and one multicenter randomized controlled trial met the inclusion criteria. There were not any recently used endodontic materials that would not induce at least measurable colour changes. For a wide range of materials currently available on the market there is only scarce or no evidence available on their staining ability. Endodontic therapy should not focus solely on biological and functional aspects, but take aesthetic considerations into account as well. To reduce the risk of material-induced tooth discoloration all materials should be applied carefully in areas of aesthetic concern. The need for further research in this field and for the development of non-staining endodontic materials is evident. PMID:22513082

Krastl, Gabriel; Allgayer, Nikola; Lenherr, Patrik; Filippi, Andreas; Taneja, Pankaj; Weiger, Roland

2012-04-19

334

Custom-made, root-analogue direct laser metal forming implant: a case report.  

PubMed

In the last few years, the application of digital technology in dentistry has become widespread with the introduction of cone beam computed tomography (CBCT) scan technology, and considerable progress has been made in the development of computer-aided design/ computer-aided manufacturing (CAD/CAM) techniques, including direct laser metal forming (DLMF). DLMF is a technology 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. At present, the combined use of CBCT 3D data and CAD/CAM technology makes it possible to manufacture custom-made, root-analogue implants (RAI) with sufficient precision. This report demonstrates the successful clinical use of a custom-made, root-analogue DLMF implant. CBCT images of a non-restorable right maxillary first premolar were acquired and transformed into a 3D model. From this model, a custom-made, root-analogue DLMF implant was fabricated. Immediately after tooth extraction, the RAI with a pre-operatively designed abutment was placed in the extraction socket and restored with a single crown. At the 1-year follow-up examination, the RAI showed a good functional and aesthetic integration. The introduction of DLMF technology signals the start of a new revolutionary era for implant dentistry as its immense potential for producing highly complex macro- and microstructures is receiving vast interest in different medical fields. PMID:22699801

Mangano, Francesco Guido; Cirotti, Bruno; Sammons, Rachel Lilian; Mangano, Carlo

2012-06-15

335

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

336

An inductive signalling network regulates mammalian tooth morphogenesis with implications for tooth regeneration.  

PubMed

Sequential and reciprocal epithelial-mesenchymal interactions, essential throughout such aspects of tooth morphogenesis as patterning, size and number of teeth, involves a well-ordered series of inductive and permissive signals that exert global control over cell proliferation, differentiation and organogenesis. In particular, growth factors, transcription factors and their corresponding receptors, as well as other soluble morphogens, make up a regulatory network at the molecular level that synergistically or antagonistically controls intra-/inter-cellular signal transduction during odontogenesis. This review summarizes recent advances in the study of crucial signalling pathways, for example of BMPs, Wnt, Notch, Shh and FGF, with emphasis on the potential integrated signalling network responsible for tooth formation. Our work probes into the complexity of these inductive signalling pathways to promote the understanding of tooth regeneration. Additionally, our study provides further insights into therapeutic strategies for various dental abnormalities in patterning and number, such as tooth agenesis and supernumerary teeth. PMID:23952789

Li, Z; Yu, M; Tian, W

2013-08-17

337

The oral medicine of tooth wear.  

PubMed

This review illustrates, through a series of case histories, how oral medicine insights aid the diagnosis and management of patients with excessive tooth wear. The cases reviewed are drawn from the records of 500 southeast Queensland patients referred to the author over a 12 year period. Patients most at risk of dental erosion have work and sports dehydration, caffeine addiction, gastro-oesophageal reflux, asthma, diabetes mellitus, hypertension or other systemic diseases or syndromes that predispose to xerostomia. Saliva protects the teeth from the extrinsic and intrinsic acids which cause dental erosion. Erosion, exacerbated by attrition and abrasion, is the main cause of tooth wear. These cases illustrate that teeth, oral mucosa, salivary glands, skin and eyes should be examined for evidence of salivary hypofunction and attendant medical conditions. Based on comprehensive oral medicine, dietary analyses and advice, it would seem patients need self-management plans to deal with incipient chronic tooth wear. The alternative is the expensive treatment of pain, occlusal damage and pulp death required to repair the effects of acute severe tooth wear. PMID:11838870

Young, W G

2001-12-01

338

Tooth wear: diet analysis and advice.  

PubMed

Diet analysis and advice for patients with tooth wear is potentially the most logical intervention to arrest attrition, erosion and abrasion. It is saliva that protects the teeth against corrosion by the acids which soften enamel and make it susceptible to wear. Thus the lifestyles and diet of patients at risk need to be analysed for sources of acid and reasons for lost salivary protection. Medical conditions which put patients at risk of tooth wear are principally: asthma, bulimia nervosa, caffeine addiction, diabetes mellitus, exercise dehydration, functional depression, gastroesophageal reflux in alcoholism, hypertension and syndromes with salivary hypofunction. The sources of acid are various, but loss of salivary protection is the common theme. In healthy young Australians, soft drinks are the main source of acid, and exercise dehydration the main reason for loss of salivary protection. In the medically compromised, diet acids and gastroesophageal reflux are the sources, but medications are the main reasons for lost salivary protection. Diet advice for patients with tooth wear must: promote a healthy lifestyle and diet strategy that conserves the teeth by natural means of salivary stimulation; and address the specific needs of the patients' oral and medical conditions. Individualised, patient-empowering erosion WATCH strategies; on Water, Acid, Taste, Calcium and Health, are urgently required to combat the emerging epidemic of tooth wear currently being experienced in westernised societies. PMID:15880960

Young, William George

2005-04-01

339

Isotopic Alteration of Mammalian Tooth Enamel  

Microsoft Academic Search

Mammalian tooth enamel carbonates from a Pliocene site at Allia Bay in northern Kenya show variable carbon and oxygen isotopic alteration. Sample screening by cathodoluminescence, prior to isotopic analysis, identified areas of extensive chemical alteration and others that were minimally altered. The luminescent patterns were used to guide sampling for the isotope study. Carbon stable isotope ratios of the apatite

M. J. SCHOENINGER; K. HALLIN; H. REESER; JOHN W. VALLEYc; JOHN FOURNELLEc

340

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

2010-08-01

341

Gastroesophageal Reflux Disease and Tooth Erosion  

PubMed Central

The increasing prevalence of gastroesophageal reflux disease (GERD) in children and adults, and of “silent refluxers” in particular, increases the responsibility of dentists to be alert to this potentially severe condition when observing unexplained instances of tooth erosion. Although gastroesophageal reflux is a normal physiologic occurrence, excessive gastric and duodenal regurgitation combined with a decrease in normal protective mechanisms, including an adequate production of saliva, may result in many esophageal and extraesophageal adverse conditions. Sleep-related GERD is particularly insidious as the supine position enhances the proximal migration of gastric contents, and normal saliva production is much reduced. Gastric acid will displace saliva easily from tooth surfaces, and proteolytic pepsin will remove protective dental pellicle. Though increasing evidence of associations between GERD and tooth erosion has been shown in both animal and human studies, relatively few clinical studies have been carried out under controlled trial conditions. Suspicion of an endogenous source of acid being associated with observed tooth erosion requires medical referral and management of the patient as the primary method for its prevention and control.

Ranjitkar, Sarbin; Kaidonis, John A.; Smales, Roger J.

2012-01-01

342

The Genetic Control of Early Tooth Development  

Microsoft Academic Search

Most vertebrate organs begin their initial formation by a common, developmentally conserved pattern of inductive tissue interactions between two tissues. The developing tooth germ is a prototype for such inductive tissue interactions and provides a powerful experimental system for elucidation of the genetic pathways involved in organogenesis. Members of the Msx homeobox gene family are expressed at sites of epithelial-mesenchymal

R. Maas; M. Bei

1997-01-01

343

Sexual Dimorphism of Modern Tooth Crown Tissues  

Microsoft Academic Search

This study presents data on the extent of the sexual dimorphism observed in tissue measurements of the deciduous tooth crowns for a heterogeneous modem human sample. A series of linear and area measurements were taken from crowns sectioned in a buccolingual plane. The buccal enamel and perpendicular buccal enamel, situated towards the incisal surface, are significantly thicker in female deciduous

Andrea H. W. Chan

2007-01-01

344

Second-Harmonic Generation Microscopy of Tooth.  

National Technical Information Service (NTIS)

In this study, we have developed a high performance microscopic system to perform second-harmonic (SH) imaging on a tooth. The high sensitivity of the system allows acquisition rate of 300 seconds/frame with resolution at 512x512 pixels. The surface SH si...

F. Kao M. Huang P. Cheng S. L. Huang Y. Wang

2000-01-01

345

A comparison of peripheral marginal bone loss at dental implants measured with conventional intraoral film and digitized radiographs.  

PubMed

The purpose of the present study was to examine the effects of conventional and bone-condensing implantation techniques and time (6 and 12 months after implantation) on levels of marginal bone surrounding implants and to assess the level of agreement between measurements made using digitized intraoral images and film. The study group consisted of 14 healthy patients (9 female, 5 male; age range, 23-59 years; mean age, 41.1 years) with 28 single-tooth dental implants. In each patient, an implant was placed on one side using a conventional technique and on the opposite side using a bone-condensing technique. Film radiographs were taken at 6 and 12 months following implant placement and were digitized at 300 dpi and 600 dpi using a laser scanner. All scanned images were stored as both TIFF and JPEG files. A single observer twice measured distal and mesial marginal bone loss from film and digitized images. At the mesial site, there was a significant main effect of time (6 and 12 months after implantation) on the measurement of bone loss, F(1, 26) = 6.08, P = .02, but no significant main effect of implantation technique, F(1, 26) = 1.56, P = .223, and no significant interaction between time and technique, F(1, 26) = 2.09, P = .160. Similarly, at the distal site, there was a significant main effect of time on the measurement of bone loss, F(1, 26) = 14.1, P = .001, but no significant main effect of implantation technique, F(1, 26) = 1.21, P = .281. However, in contrast to the mesial site, there was also significant interaction between technique and time on the distal site, F(1, 26) = 4.974, P = .035. Intraobserver intraclass correlation coefficients and repeatability measurements showed high agreement for all image types. The bone-condensing technique resulted in greater marginal bone loss. Marginal bone measurements made using digitized intraoral images and conventional film showed high levels of agreement. PMID:20712442

Kamburo?lu, K?vanç; Gül?ah?, Ay?e; Genç, Yasemin; Paksoy, Candan Semra

2010-08-16

346

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

347

Positioning the actual interference fringe pattern on the tooth flank in measuring gear tooth flanks by laser interferometry  

NASA Astrophysics Data System (ADS)

In measuring form deviation of gear tooth flanks by laser interferometry, the collected interference fringe pattern (IFP) is badly distorted, in the case of shape, relative to the actual tooth flank. Meanwhile, a clear and definite mapping relationship between the collected IFP and the actual tooth flank is indispensable for both transforming phase differences into deviation values and positioning the measurement result on the actual tooth flank. In order to solve these problems, this paper proposes a method using the simulation tooth image as a bridge connecting the actual tooth flank and the collected IFP. The mapping relationship between the simulation tooth image and the actual tooth flank has been obtained by ray tracing methods [Fang et al., Appl. Opt. 49(33), 6409-6415 (2010)]. This paper mainly discusses how to build the relationship between the simulation tooth image and the collected IFP by using a matching algorithm of two characteristic point sets. With the combination of the two above-mentioned assistant mapping relationships, the mapping relationship between the collected IFP and the actual tooth flank can be built; the collected IFP can be positioned on the actual tooth flank. Finally, the proposed method is employed in a measurement of the form deviation of a gear tooth flank and the result proves the feasibility of the proposed method.

Fang, Suping; Wang, Leijie; Liu, Shiqiao; Komori, Masaharu; Kubo, Aizoh

2011-05-01

348

Goserelin Implant  

MedlinePLUS

... as an implant to be inserted with a syringe subcutaneously (under the skin) in your stomach area ... written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as ...

349

Hip Implants  

MedlinePLUS

... advances in the design, construction, and implantation of artificial hip joints, resulting in a high percentage of ... number of measurements to ensure proper prosthesis selection, limb length, and hip rotation. After making the incision, ...

350

Carmustine Implant  

MedlinePLUS

Carmustine implant is used along with surgery and sometimes radiation therapy to treat malignant glioma (a certain type of cancerous brain tumor). Carmustine is in a class of medications called alkylating agents. It works by slowing or stopping ...

351

A review of 198 patients (389 implants) who had breast implants removed.  

PubMed

Because of the large number of women now returning to their plastic surgeons with concerns about their breast implants many years after surgery, we are afforded an ideal opportunity to evaluate these patients over the long-term. This study reviewed 198 patients (389 implants) who underwent explantation by two surgeons over a 2-year period, correlating prosthesis type, location, and length of time since implantation with two adverse endpoints, implant rupture and symptomatic capsular contracture. Significant findings included a relatively high rate of implant rupture in patients whose implants had been in place over 20 years, an increased incidence of both symptomatic capsular contracture and implant rupture in single lumen gel implants and a positive correlation between severity of capsular contracture and implant rupture. PMID:10163505

Netscher, D T; Walker, L E; Weizer, G; Thornby, J; Wigoda, P; Bowen, D

1995-01-01

352

Wear now? An update on the etiology of tooth wear.  

PubMed

Tooth wear is an ever-increasing problem, and younger patients are particularly at risk. The problem is likely to continue as patients' demands and expectations rise and as more natural teeth are retained into old age. The etiology of tooth wear is reviewed, with emphasis on those factors that appear to be major contributors to the problem at the moment. The clinical appearance of tooth wear is also discussed. It would appear that erosive factors are a significant cause of tooth wear. The prominence of acidic damage of tooth tissue is probably a reflection of society's concern with healthy eating and appearance. PMID:9452693

Bishop, K; Kelleher, M; Briggs, P; Joshi, R

1997-05-01

353

Should Patients with Implantable Cardioverter-Defibrillators Be Allowed to Drive? Observations in 291 Patients from a Single Center over an 11-year Period  

Microsoft Academic Search

Motor-vehicle driving restrictions for patients with implantable cardioverter-defibrillators (ICDs) vary widely throughout the world because safety concerns have never been adequately resolved in this patient population. To address this issue, we examined the driving behavior of 291 ICD patients to correlate the frequency of device therapy during driving, the occurrence of syncopal symptoms, and the incidence of traffic accidents. Fifty

Hans-Joachim Trappe; Paul Wenzlaff; Gert Grellman

1998-01-01

354

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

355

Multilobed mesiodens: a supernumerary tooth with unusual morphology.  

PubMed

An 8-year-old boy came with a chief complaint of an abnormally shaped tooth situated in upper front teeth region. On examination a supernumerary tooth with multiple lobes was present palatally to the maxillary right permanent central incisor. The morphology of the tooth crown was found to be unusual due to the presence of five lobes in the crown portion. Because of the supernumerary tooth, the permanent right central incisor was displaced labially. Radiographic examination showed a completely formed supernumerary tooth with dilacerated root. On the basis of clinical and radiographic examination, the supernumerary tooth was diagnosed as multilobed mesiodens. Since patient expressed dissatisfaction with the presence of supernumerary tooth, it was decided to extract this mesiodens followed by orthodontic treatment for alignment of labially placed maxillary right permanent central incisor. PMID:23391956

Dave, Bhavna; Patel, Jalark; Swadas, Milan; Mallikarjuna, Rachappa

2013-02-06

356

The effect of a tooth gingival transplantation on periodontal healing.  

PubMed

We investigated the effects of a tooth gingival transplantation (TGT) on autologous tooth transplantation using tooth with both periodontal ligament and gingiva. Stabilization period, degree of tooth mobility, and periodontal pocket depth (PPD) were compared with those of transplanted teeth using the conventional method (tooth with periodontal ligament). The subjects were 76 healthy adults (56 cases for the conventional method and 20 cases for TGT). Stabilization period of the tooth was shorter in the cases of TGT than that of the conventional method. Degree of tooth mobility was almost the same for TGT and the conventional technique. The value of PPD at 12 weeks after operation was better in the TGT group than in the conventional method group. The results for both stabilization period and PPD were better in TGT than in the conventional method, indicating low risk for periodontal disease in TGT. PMID:12848714

Tsubura, Shuichi; Ikeda, Yuichi

2003-08-01

357

Blood lead--tooth lead relationship among Boston children  

SciTech Connect

The amount of lead in deciduous teeth has been used extensively as a marker for infant lead exposure and body burden. Elevated tooth lead levels have been seen in children who had lead poisoning. Also, on a population wide basis tooth lead levels appear to vary according to housing status and presumably lead exposure. This exposure index has been applied using varying techniques in Denmark, and the United Kingdom. Because of the neurotoxicity of lead, the tooth lead levels of retarded and normal children have been compared. Most recently, in research of lead and child development, tooth lead levels have been used as markers of past lead exposure. Despite the widespread use of tooth lead values, very little is known about the exact time course of lead deposition in tooth from blood. This report compares blood lead levels at different ages to tooth lead levels in a group of Boston children.

Rabinowitz, M.B.; Leviton, A.; Bellinger, D.C. (Children's Hospital, Boston, MA (USA))

1989-10-01

358

Damage, refractive index and near-field intensity profiles in a single-mode waveguide of LiNbO3 by 400 keV He ion implantation  

NASA Astrophysics Data System (ADS)

We report on a single-mode waveguide in lithium niobate produced by 400 keV He ion implantation with a dose of 3 × 1016 ions cm-2 at liquid nitrogen temperature. Rutherford backscattering/channelling spectra have been measured in the waveguide before and after annealing and the damage profile has been extracted. The shape of the measured damage profile is similar to that of the ordinary refractive index by the intensity calculation method. The near-field intensity profile in a ridge waveguide is given and the propagation loss for the extraordinary index is estimated to be 1.9 dB cm-1.

Zhang, S. M.; Liu, X. H.; Qin, X. F.; Wang, K. M.; Liu, X.

2010-11-01

359

Breast reconstruction with prosthetic implants.  

PubMed

For patients who undergo mastectomy for the treatment of breast cancer, the restoration of a normal breast form through breast reconstruction is important to body image and quality of life. Implant-based reconstruction has the capability of producing excellent results in the well selected patient. In addition, compared with autogenous tissue reconstruction, implant reconstruction offers a shorter operative procedure with a quicker convalescence and no donor site morbidity. Reconstruction options for implant-based reconstruction include: single-stage reconstruction with a standard or adjustable implant, tissue expansion followed by placement of a permanent implant, or combined autologous tissue/implant reconstruction. Procedure selection is based on a range of patient variables, including: location and type of breast cancer, availability of local, regional and distant donor tissue, size and shape of the desired breast(s), surgical risk, and most importantly, patient preference. Although satisfactory results can be obtained with single-stage reconstruction, in most of patients, a more reliable approach involves two-stage expander/implant reconstruction. Individualizing selection of a reconstructive technique for each patient will be the predominant factor in achieving a reconstructive success. PMID:18677130

Mesbahi, Ali N; McCarthy, Colleen M; Disa, Joseph J

360

Are success and survival rates of early implant placement higher than immediate implant placement?  

PubMed

Immediate placement refers to the placement of an implant into a tooth socket at the time of extraction; early placement refers to the placement of an implant after substantial gingival healing, but before any clinically significant bone fill occurs within the socket. This study evaluated the success and survival rates of implants following immediate and early placement. 50 implants were placed in 36 patients. 26 immediate (group I) and 24 early placements (group II) were performed. Pain or tenderness with function, mobility, radiographic bone loss from initial surgery and exudate history were evaluated. Mean vertical bone loss in the immediate placement group was 0.55 mm and 0.80 mm in the early placement group. The survival rate for the immediate placement group was 96.16% with 51.6 months follow-up and in the early placement group was 100% with 61.9 months follow-up. The results of this study suggest that although the success and survival rates of early placed implants were a little higher and the follow up period was longer than immediately placed implants, the difference was not remarkable. In conclusion, both implant insertion techniques are safe and reliable procedures with considerably high survival rates. PMID:23142021

Soydan, S S; Cubuk, S; Oguz, Y; Uckan, S

2012-11-08

361

Large scale study of tooth enamel  

SciTech Connect

Human tooth enamel contains traces of foreign elements. The presence of these elements is related to the history and the environment of the human body and can be considered as the signature of perturbations which occur during the growth of a tooth. A map of the distribution of these traces on a large scale sample of the population will constitute a reference for further investigations of environmental effects. One hundred eighty samples of teeth were first analysed using PIXE, backscattering and nuclear reaction techniques. The results were analysed using statistical methods. Correlations between O, F, Na, P, Ca, Mn, Fe, Cu, Zn, Pb and Sr were observed and cluster analysis was in progress. The techniques described in the present work have been developed in order to establish a method for the exploration of very large samples of the Belgian population.

Bodart, F.; Deconninck, G.; Martin, M.Th.

1981-04-01

362

Distribution of amelotin in mouse tooth development.  

PubMed

Amelotin is expressed and secreted by ameloblasts in tooth development, but amelotin distribution during enamel development is not clear. In this report, we first investigated amelotin expression in developing teeth by immunohistochemistry. Amelotin was detected in the enamel matrix at the secretion and maturation stages of enamel development. Amelotin was also observed at Tomes' processes on the apical ends of secretory ameloblasts. We then compared amelotin gene expression with those of amelogenin, enamelin, and ameloblastin in the mandibles of postnatal mice by RT-PCR. The expression of amelotin was detected as early as in postnatal day 0 mandibles and amelotin was coexpressed with amelogenin, ameloblastin, and enamelin during tooth development. These data strongly suggest that amelotin is an enamel matrix protein expressed at the secretion and maturation stages of enamel development. PMID:19937642

Gao, Yuguang; Wang, Wanchun; Sun, Yan; Zhang, Juanjuan; Li, Dongliang; Wei, Yahong; Han, Tingting

2010-01-01

363

Discharge activities of neurons in the nucleus paragigantocellularis during the development of morphine tolerance and dependence: A single unit study in chronically implanted rats  

Microsoft Academic Search

The nucleus paragigantocellularis (PGi) has been proposed to play a role in opiate dependence\\/withdrawal. In the present study, we examined the discharge activity of PGi neurons before and after the development of morphine tolerance\\/dependence in rats. A multi-wire electrode was chronically implanted in the PGi, which allowed us to monitor the effects of both acute and chronic morphine treatments on

Hong Zhu; Wu Zhou

2010-01-01

364

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 100ng/?l was able to induce strong CCN2 expression while a minimum concentration of 25ng/?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

2013-08-31

365

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

366

Nature, Red in Tooth and Claw 1  

Microsoft Academic Search

“Nature, Red in Tooth and Claw” explores Adorno’s ideas about our mediated relationship with nature. The first section of\\u000a the paper examines the epistemological significance of his thesis about the preponderance of the object while describing the\\u000a Kantian features in his notion of mediation. Adorno’s conception of nature will also be examined in the context of a review\\u000a of J.

Deborah Cook

2007-01-01

367

Expression of HMGB1 during tooth development  

Microsoft Academic Search

High mobility group box 1 (HMGB1) is a nuclear and cytosolic protein that can act as a transcription factor, a growth factor,\\u000a or a cytokine. To elucidate a possible role for HMGB1 in tooth development, we have studied the expression of HMGB1 and its\\u000a receptor RAGE (receptor for advanced glycation end-products) during the late fetal and early postnatal period of

R. Sugars; E. Karlström; C. Christersson; M.-L. Olsson; M. Wendel; K. Fried

2007-01-01

368

Atomic force microscopy study of tooth surfaces.  

PubMed

Atomic force microscopy (AFM) was used to study tooth surfaces in order to compare the pattern of particle distribution in the outermost layer of the tooth surfaces. Human teeth and teeth from a rodent (Golden hamster), from a fish (piranha), and from a grazing mollusk (chiton) with distinct feeding habits were analyzed in terms of particle arrangement, packing, and size distribution. Scanning electron microscopy and transmission electron microscopy were used for comparison. It was found that AFM gives high-contrast, high-resolution images and is an important tool as a source of complementary and/or new structural information. All teeth were cleaned and some were etched with acidic solutions before analysis. It was observed that human enamel (permanent teeth) presents particles tightly packed in the outer surface, whereas enamel from the hamster (continuously growing teeth) shows particles of less dense packing. The piranha teeth have a thin cuticle covering the long apatite crystals of the underlying enameloid. This cuticle has a rough surface of particles that have a globular appearance after the brief acidic treatment. The similar appearance of the in vivo naturally etched tooth surface suggests that the pattern of globule distribution may be due to the presence of an organic material. Elemental analysis of this cuticle indicated that calcium, phosphorus, and iron are the main components of the structure while electron microdiffraction of pulverized cuticle particles showed a pattern consistent with hydroxyapatite. The chiton mineralized tooth cusp had a smooth surface in an unabraded region and a very rough structure with the magnetite crystals (already known to make part of the structure) protruding from the surface. It was concluded that the structures analyzed are optimized for efficiency in feeding mechanism and life span of the teeth. PMID:10196115

Farina, M; Schemmel, A; Weissmüller, G; Cruz, R; Kachar, B; Bisch, P M

1999-03-01

369

Sensitivity of tooth enamel to penetrating radiation  

SciTech Connect

Since integral radiation doses are important in the causation of cancers, this article proposes that everyone should carry a dosimeter that stores accumulated information over many decades. It is further noted that tooth enamel can serve as such a dosimeter. Ionizing radiation produces carbonate radicals, with a concentration linearly related to the absorbed dose. In this paper, the sensitivities of teeth to gamma and beta radiation has been measured.

Mel`nikov, P.V.; Moiseev, B.M.

1994-04-01

370

Functional Tooth Regeneration Using a Bioengineered Tooth Unit as a Mature Organ Replacement Regenerative Therapy  

PubMed Central

Donor organ transplantation is currently an essential therapeutic approach to the replacement of a dysfunctional organ as a result of disease, injury or aging in vivo. Recent progress in the area of regenerative therapy has the potential to lead to bioengineered mature organ replacement in the future. In this proof of concept study, we here report a further development in this regard in which a bioengineered tooth unit comprising mature tooth, periodontal ligament and alveolar bone, was successfully transplanted into a properly-sized bony hole in the alveolar bone through bone integration by recipient bone remodeling in a murine transplantation model system. The bioengineered tooth unit restored enough the alveolar bone in a vertical direction into an extensive bone defect of murine lower jaw. Engrafted bioengineered tooth displayed physiological tooth functions such as mastication, periodontal ligament function for bone remodeling and responsiveness to noxious stimulations. This study thus represents a substantial advance and demonstrates the real potential for bioengineered mature organ replacement as a next generation regenerative therapy.

Imamura, Aya; Ogawa, Miho; Yasukawa, Masato; Yamazaki, Hiromichi; Morita, Ritsuko; Ikeda, Etsuko; Nakao, Kazuhisa; Takano-Yamamoto, Teruko; Kasugai, Shohei; Saito, Masahiro; Tsuji, Takashi

2011-01-01

371

[Experimental model of tooth mobility in the human "in vivo"].  

PubMed

The aim of the present study was to investigate experimentally the mechanical properties of tooth deflection under external loading. These properties have a significant impact on tooth movement during orthodontic treatment. The stresses and strains caused by tooth movement influence bone remodelling, which is the basis of orthodontic treatment. The movement of a tooth as a direct reaction to the forces acting on it is termed "initial" movement. It is nonlinear and has a clearly time-dependent component. While the initial tooth movement represents the totality of the reaction mechanisms of all the tissues of the tooth unit, it is determined primarily by the mechanical properties of the periodontal ligament (PDL). The PDL is the softest tissue of the tooth unit and is therefore subject to the largest deformations when forces act on the crown of the tooth. The objective of orthodontic treatment is to achieve as precise and rapid tooth movement as possible, without provoking such undesired effects as bone and root resorption. To enable the implementation of an optimal orthodontic force system that meets these requirements, a thorough knowledge of the biomechanics of tooth movement is a must. PMID:11921633

Dorow, C; Krstin, N; Sander, F G

372

A report of an impacted primary maxillary central incisor tooth.  

PubMed

- Primary tooth impaction is a rare phenomenon when compared to permanent teeth impaction. The purpose of this report is to present a 5-year-old Chinese girl who exhibited impaction of tooth 51, its unusual consequence on the permanent successor tooth and its comprehensive management. Her parents revealed that at 6 months of age, the patient had fallen from her bed and struck her face on the floor; however, there were no teeth present in the oral cavity. The intraoral examinations identified a bony-like projection on the buccal aspect of the alveolus in the 51 region. Radiographic examination revealed that tooth 51 exhibited an unfavourable orientation, with the crown directed towards the palate. Therefore, the impacted tooth 51 was surgically removed, and two years later tooth 11 erupted into the oral cavity with an indentation on its incisal aspect, which resembled the crown of the primary teeth, thus giving the appearance of a tooth within a tooth or 'dens in dente'. Subsequently, enameloplasty and composite resin build-up was performed on tooth 11 for aesthetic reasons. It is very unusual to have the clinical crowns of both primary and permanent teeth in such close proximity within the alveolar bone, and the present case is a good example to emphasize that trauma to the primary teeth is of considerable importance due to the close proximity of the primary teeth to permanent tooth germs. PMID:23305157

Anthonappa, Robert P; Ongtengco, Kristine L; King, Nigel M

2013-01-10

373

Tooth wear: the view of the anthropologist  

PubMed Central

Anthropologists have for many years considered human tooth wear a normal physiological phenomenon where teeth, although worn, remain functional throughout life. Wear was considered pathological only if pulpal exposure or premature tooth loss occurred. In addition, adaptive changes to the stomatognathic system in response to wear have been reported including continual eruption, the widening of the masticatory cycle, remodelling of the temporomandibular joint and the shortening of the dental arches from tooth migration. Comparative studies of many different species have also documented these physiological processes supporting the idea of perpetual change over time. In particular, differential wear between enamel and dentine was considered a physiological process relating to the evolution of the form and function of teeth. Although evidence of attrition and abrasion has been known to exist among hunter-gatherer populations for many thousands of years, the prevalence of erosion in such early populations seems insignificant. In particular, non-carious cervical lesions to date have not been observed within these populations and therefore should be viewed as ‘modern-day’ pathology. Extrapolating this anthropological perspective to the clinical setting has merits, particularly in the prevention of pre-mature unnecessary treatment.

2007-01-01

374

Age estimation using tooth cementum annulation.  

PubMed

In Forensic Anthropology age diagnosis of unidentified bodies significantly helps in the identification process. Among the set of established aging methods in anthropology tooth cementum annulation (TCA) is increasingly used due to its narrow error range which can reach 5 years of age in adult individuals at best. The rhythm of cementum appositions of seasonally different density provides a principal mechanism on which TCA is based. Using histological preparation techniques for hard tissues, transversal tooth root sections are produced which can be analyzed in transmitted light microscopy. Even though no standard TCA preparation protocol exists, several methodological validation studies recommend specific treatments depending on individual conditions of the teeth. Individual age is estimated by adding mean tooth eruption age to the number of microscopically detected dark layers which are separated by bright layers and stand for 1 year of age each. To assure a high reliability of the method, TCA age diagnosis has to be based on several teeth of one individual if possible and needs to be supported by different techniques in forensic cases. PMID:22907406

Wittwer-Backofen, Ursula

2012-01-01

375

Convergence angles of clinical tooth preparations achieved by dental students at king saud university, saudi arabia.  

PubMed

The appropriate convergence angle (CA) for adequate retention and resistance of cast crowns has always been a matter of research and discussion. The purpose of this study was to measure the CA of tooth preparation for single crown (SC) or as abutments for fixed partial denture (FPD) carried out by final-year undergraduate dental students at the College of Dentistry, King Saud University and to compare them with the recommended CA. The convergence angles of 355 tooth preparations were evaluated and grouped into SC preparations and FPD abutment preparations. Dies were scanned using the computer-assisted design (CAD) system (Cercon, Degudent), and snapshots were then taken from buccal and mesial views. CA was calculated from a colored printout for each snapshot using a protractor. The overall mean CA was 18.56°. Only 32.7 percent of the preparations were within the recommended CA (<12°). The mean CA of SC (17.7°) was less than the mean CA for FPD abutment preparations (19.58°). The mean CA for anterior tooth preparations (15.8°) was significantly less than the mean CA for posterior tooth preparations (20.3°). The mean CA for mesio-distal axial wall preparations (16.66°) was less than the mean CA for the buccolingual axial wall preparations (20.45°). A wide range was found for the convergence of the axial walls among dental students. The recommended CA (<12°) was difficult to achieve clinically by these students. PMID:24002853

Aleisa, Khalil; Al-Dwairi, Ziad N; Alwazzan, Khalid; Al-Moither, Meteab; Al-Shammari, Meshal; Lynch, Edward

2013-09-01

376

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

377

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

378

A close-up look at an implant fracture: a case report.  

PubMed

The authors report on the fracture of a standard endosseous dental implant 11 years after placement. It had been connected to a natural tooth using a nonrigid connector to compensate for the lack of a built-in antirotational system on the prosthetic abutment of the implant restoration. Scanning electron microscopy revealed striations on the fracture surface, suggesting a fatigue-associated failure. PMID:12449308

Velásquez-Plata, Diego; Lutonsky, James; Oshida, Yoshiki; Jones, Robert

2002-10-01

379

Cochlear Implants  

MedlinePLUS

... In With a Cochlear Implant This type of hearing loss is sensorineural , which means there is damage to the tiny hair cells in the part of the inner ear called the cochlea. Because of this damage, ... or “cured” hearing. It does, however, allow for the perception of ...

380

Quartz optical waveguide by ion implantation  

Microsoft Academic Search

We have shown single-mode surface optical waveguiding in lithium-ion-implanted fused quartz, and multimode buried waveguiding in argon- and lithium-ion-implanted fused quartz. Guide losses are observed to be of the order of 5 dB for the samples investigated for both species of ions. Described in this letter are the experimental procedures and parameters for ion implantation and the measurements for mode

David T. Y. Wei; William W. Lee; Louis R. Bloom

1973-01-01

381

Esophageal perforation by a tooth in child abuse  

Microsoft Academic Search

A unique case of child abuse in a six-year-old Hispanic girl is reported. In this case, a tooth avulsed and swallowed during an episode of physical abuse and\\/or sexual abuse, caused an esophageal perforation resulting in a retropharyngeal abscess and mediastinal abscess containing the tooth. Although traumatic esophageal injuries in child abuse have occurred, the presence of a tooth within

D. S. Ablin; M. A. Reinhart

1992-01-01

382

Tooth positioners and their effects on treatment outcome  

PubMed Central

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.

Pravindevaprasad, A.; Therese, Beena Agnes

2013-01-01

383

Quantification of jaw reflexes evoked by natural tooth contact in human subjects.  

PubMed

Inhibitory jaw reflexes are believed to be important for protecting the teeth and temporo-mandibular structures from damage during sudden or forceful biting or mastication. Accordingly, alterations in these reflexes are sometimes implicated in aetiologies proposed for oro-facial pain syndromes, although the association is not well-established. We now aim to develop a method for quantifying objectively inhibitory jaw reflexes evoked by natural tooth contact. In the longer term, this may provide a new approach to examining the association of altered reflexes and clinical conditions. Eighteen subjects gave their written, informed consent, and were recruited to participate in this study. They were instructed to clench their teeth together in response to visual cues. They performed two such tasks twenty times: from the jaw postural position and from a more open position with the jaws set 10mm apart. Both tasks produced a rapid rise then stabilisation in electromyographic activity in the masseter muscle. This was always interrupted by a large inhibitory reflex starting 11.1±1.5 ms (mean±SD) after tooth contact. The inhibitions produced during the second task were similar but of significantly longer duration (24.3±6.4 vs 18.4±6.5 ms, P=0.0003, paired t-test) and greater magnitude (measured as an integral of the waveform: 1577±478 vs 1279±425%.ms, P=0.007, paired t-test). Interestingly, in a minority (13%) of the tasks, a second inhibition with a longer latency (50.9±0.9 ms) was also observed. Thus reflex responses in the masseter muscle to natural tooth contact usually consist of single inhibitory periods. In this respect they are like those induced by externally applied tooth pushing although occasionally there is a second inhibition, reminiscent of that seen with externally applied tooth taps. PMID:21419390

Ainine, Salma; Mason, Andrew G; Cadden, Samuel W

2011-03-17

384

Age estimation by pulp/tooth ratio in lower premolars by orthopantomography.  

PubMed

Accurate age estimation has always been a problem for forensic scientists, and apposition of secondary dentine is often used as an indicator of age. Since 2004, in order to examine patterns of secondary dentine apposition, Cameriere et al. have been extensively studying the pulp/tooth area ratio of the canines by panoramic and peri-apical X-ray images. The main aim of this paper is to examine the relationship between age and age-related changes in the pulp/tooth area ratio in monoradicular teeth, with the exception of canines, by orthopantomography. A total of 606 orthopantomograms of Spanish white Caucasian patients (289 women and 317 men), aged between 18 and 75 years and coming from Bilbao and Granada (Spain), was analysed. Regression analysis of age of monoradicular teeth indicated that the lower premolars were the most closely correlated with age. An ANCOVA did not show significant differences between men and women. Multiple regression analysis, with age as dependent variable and pulp/tooth area ratio as predictor, yielded several formulae. R(2) ranged from 0.69 to 0.75 for a single lower premolar tooth and from 0.79 to 0.86 for multiple lower premolar teeth. Depending on the available number of premolar teeth, the mean of the absolute values of residual standard error, at 95% confidence interval, ranged between 4.34 and 6.02 years, showing that the pulp/tooth area ratio is a useful variable for assessing age with reasonable accuracy. PMID:21821373

Cameriere, Roberto; De Luca, Stefano; Alemán, Inmaculada; Ferrante, Luigi; Cingolani, Mariano

2011-08-06

385

Single-cell polymerase chain reaction-based pre-implantation genetic diagnosis using fragment analysis for ?-thalassemia in an Indian couple with ?-globin gene mutations.  

PubMed

Despite advances in diagnostic techniques, approximately 10,000 babies with ?-thalassemia major are born annually in India. Pre-implantation genetic diagnosis (PGD), an alternative to prenatal diagnosis, helps in negative selection of affected embryos prior to implantation. Hereby, we report the first successful ?-thalassemia PGD pregnancy in an Indian carrier couple. ?-Thalassemia mutation analysis by Amplification-Refractory Mutation Sequence (ARMS)-polymerase chain reaction (PCR) in the parents, followed by PGD for ?-thalassemia mutation in embryos in two consequent in vitro fertilization (IVF) cycles, with transfer for three ?-thalassemia minor embryos, resulted in singleton successful pregnancy, the results of which were confirmed on prenatal diagnosis. With advances in assisted reproductive techniques and molecular diagnosis, PGD for monogenic diseases is feasible in high-risk couples. The methodology in the current study included two rounds of PCR using fluorescently labeled primers, fragment analysis using the ABI 3100 nucleotide sequencer and the GeneMapper software, purification, and concentration of PCR product, which enabled distinct clear peaks making the analysis and interpretation non-ambiguous. PMID:23532358

Gada Saxena, Shailaja; Saranath, Dhananjaya

2012-09-01

386

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

387

Dynamic tooth loads of planetary gear sets having tooth profile wear  

Microsoft Academic Search

A computational model of a planetary gear set is employed to study the influence of surface wear on the dynamic behavior of a typical planetary gear set. The overall computational scheme combines a wear model that defines geometric description of contacting gear tooth surfaces having wear and a deformable-body dynamic model of a planetary gear set. The wear model employs

C. Yuksel; A. Kahraman

2004-01-01

388

Lithium iodate planar waveguides by proton implantation  

Microsoft Academic Search

Permanent optical waveguides have been produced by proton implantation in LiIO3 single crystals by using a Van De Graaff accelerator. The effects of the crystal cut and of the implantation paramaters on the optical waveguides properties, investigated by dark line mode spectroscopy, are presented. The profiles of the ordinary and extraordinary refractive indices are reconstructed by an inverse WKB method.

Christine Rosso; Paul Moretti; Christine Galez; Jacques Mugnier; Denis Barbier; Jacques Bouillot

1997-01-01

389

Thermal decomposition of human tooth enamel  

Microsoft Academic Search

Summary  Further insight into human tooth enamel, dense fraction (TE), has been obtained by following the change and loss of CO3\\u000a 2?, OH?, structurally incorporated H2O, Cl?, and, indirectly, HPO4\\u000a 2? after TE had been heated in N2 or vacuum in the range 25–1000°C. Quantitative infrared spectroscopic, lattice parameter, and thermogravimetric measures\\u000a were used. Loss of the CO3\\u000a 2? components begins

D. W. Holcomb; R. A. Young

1980-01-01

390

21 CFR 872.3900 - Posterior artificial tooth with a metal insert.  

Code of Federal Regulations, 2013 CFR

...false Posterior artificial tooth with a metal insert. 872.3900 Section 872...3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is a porcelain device with...

2013-04-01

391

Altered sensation caused by peri-implantitis: a case report.  

PubMed

Frequently reported is a case wherein a lesion caused by periodontitis or periapical lesion in a natural tooth enlarged, invaded the inferior alveolar nerve canal, and induced paresthesia. Cases wherein paresthesia occurred because of peri-implantitis have been rarely reported. The patient in this case report had experienced transient paresthesia after implant placement and recovered normal sensation 3 months later. Thirteen years later, this patient visited the authors' hospital with paresthesia in the same region because the peri-implantitis progressed to the apex of the implant. One week after removal of the implant, sense recovery and pain relief started, and 15 days after removal, the paresthesia and pain completely disappeared. For patients who experience transient paresthesia and recovery owing to nerve damage caused by the placement of an implant in the mandibular molar or premolar area, or in patients in whom the implant is close to the inferior alveolar nerve canal or the mental nerve, the spread of inflammation caused by peri-implantitis can induce paresthesia. PMID:22749709

Kim, Jong-Eun; Shim, Ji-Suk; Huh, Jung-Bo; Rim, Jae-Suk; Lee, Jeong-Yol; Shin, Sang-Wan

2012-06-29

392

Penile Implants  

Microsoft Academic Search

Effective penile implants were introduced in the early 1970s and have provided a predictable and reliable treatment of erectile\\u000a dysfunction. They can be placed in almost all circumstances in which more conservative treatments have been ineffective or\\u000a are contraindicated. Manufacturers of these devices have improved their functioning and durability, and repair rates are low\\u000a when compared with other mechanical products.

Steven K. Wilson; John J. Mulcahy

393

Interproximal wear facets and tooth associations in the Pa?alar hominoid sample.  

PubMed

Interproximal wear facets were examined on hominoid teeth from the middle Miocene site at Pa?alar, Turkey. The aim was to find matches between adjacent premolar and molar teeth from single individuals that were collected in the field as isolated teeth and use them to reconstruct tooth rows. These were then used to investigate: (1) the wear gradient on the molar teeth; (2) the dispersal of teeth from single mandibles and maxillae; (3) the size ratios among the molars; and (4) the number of individuals represented by the hominoid sample. Facets were scored for size and shape and were assessed visually using photographs and superimposed outline drawings on acetate transparencies. Out of a sample of approximately 1,500 teeth collected between 1983 and 1996, 532 molars and 258 premolars produced apparent matches making up 160 tooth rows. These were then examined rigorously for morphological consistency and state of wear, and, employing the criterion that only the most unequivocal associations should be used, the final number was reduced to 48 tooth rows-31 mandibular and 17 maxillary. The tooth associations represent a minimum of 21 individuals and probably as many as 34. Molar wear was rapid, with M1s having almost twice as much wear as M3s, as measured by a wear-gradient index. The M2s are intermediate but generally closer to M1s in degree of wear, as are P4s. This wear pattern suggests either delayed eruption of M3s or extremely abrasive diets causing rapid, heavy wear. There is some indication that the wear patterns in Griphopithecus alpani and Kenyapithecus kizili are different, with the latter perhaps having a lower wear gradient, but the K. kizili sample is very small. In both species, the M2 is the largest molar and the M1 is the smallest. Separation of individual teeth in the 48 tooth associations varied from widely separated-up to 8.5m apart-to within a few centimeters of each other. One tooth row (D922) was found with the teeth in contact but the maxillary bone had dissolved away. Two dispersal mechanisms have been identified from earlier taphonomic work: transport of disarticulated elements to the fossil site and reworking of sediments by spring action. PMID:18395120

Gençturk, Insaf; Alpagut, Berna; Andrews, Peter

2008-04-01

394

Fate of HERS during Tooth Root Development  

PubMed Central

Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS cells are attached to the surface of the cementum, and others separate to become the epithelial rest of Malasez. HERS cells secrete extracellular matrix components onto the surface of the dentin before dental follicle cells penetrate the HERS network to contact dentin. HERS cells also participate in the cementum development and may differentiate into cementocytes. During root development, the HERS is not interrupted, and instead the HERS cells continue to communicate with each other through the network structure. Furthermore, HERS cells interact with cranial neural crest derived mesenchyme to guide root development. Taken together, the network of HERS cells is crucial for tooth root development.

Huang, Xiaofeng; Bringas, Pablo; Slavkin, Harold C.; Chai, Yang

2009-01-01

395

Intrauterine hormone effects on tooth dimensions.  

PubMed

The human dentition is a complex adaptive system that is influenced by genetic, epigenetic, and environmental factors. Within this system, is sexual dimorphism related to the growth promotion of the Y chromosome, or to hormonal influences, or both? This study is the first to investigate both primary and permanent tooth sizes in females from opposite-sex dizygotic (DZOS) twin pairs compared with females from dizygotic same-sex (DZSS) and monozygotic (MZ) twin pairs to indicate the influence of intrauterine male hormone, including the initial testosterone surge, on dental development. Serial dental models of the primary, mixed, and permanent dentitions of 134 females from DZOS, DZSS, and MZ twins were examined. Mesiodistal, buccolingual, crown height, and intercuspal dimensions of all primary teeth and selected permanent teeth were determined by image analysis. Univariate and multivariate analyses showed statistically significantly larger crown size in DZOS females in both dentitions, with the crown height dimensions displaying the greatest increase in size. These findings strongly support the Twin Testosterone Transfer (TTT) hypothesis. We propose that the growth-promoting effects of the Y chromosome and intrauterine male hormone levels influence different tooth dimensions and contribute differentially to the sexual dimorphism of human teeth. PMID:23549090

Ribeiro, D C; Brook, A H; Hughes, T E; Sampson, W J; Townsend, G C

2013-04-02

396

LANGUAGE DEVELOPMENT IN PROFOUNDLY DEAF CHILDREN WITH COCHLEAR IMPLANTS  

Microsoft Academic Search

Although cochlear implants improve the ability of pro- foundly deaf children to understand speech, critics claim that the published literature does not document even a single case of a child who has developed a linguistic system based on input from an implant. Thus, it is of clinical and scientific importance to determine whether cochlear implants facilitate the development of English

Mario A. Svirsky; Amy M. Robbins; Karen Iler Kirk; David B. Pisoni; Richard T. Miyamoto

2000-01-01

397

Live demonstration: Inductive power and telemetry for micro-implant  

Microsoft Academic Search

A prototype for a wireless implantable sensor system is demonstrated intended for a pill sized micro-implant for blood sugar monitoring. Power is sent and telemetry data received over a near field inductive link. The implant system is almost completely realized on a single CMOS ASIC, excepting three surface mounted capacitors, the coil antenna and the sensor. For this demonstration, the

Philipp Häfliger

2010-01-01

398

Dynamic Measurements of Gear Tooth Friction and Load.  

National Technical Information Service (NTIS)

As part of a program to study fundamental mechanisms of gear noise, static and dynamic gear tooth strain measurements were made on the NASA gear-noise rig. Tooth-fillet strains from low-contact ratio-spur gears were recorded for 28 operating conditions. A...

B. Rebbechi F. B. Oswald D. P. Townsend

1991-01-01

399

Simulation of orthodontic tooth movements. A comparison of numerical models.  

PubMed

Orthodontic tooth movements are based on the ability of bone to react to mechanical stresses with the apposition and resorption of alveolar bone. Currently, the underlying biophysical, biochemical, and cellular processes are the subject of numerous studies. At present, however, an analytical description of orthodontic tooth movements including all components of the processes involved seems to be impossible. It was the aim of the present study to develop a mechanics-based phenomenological model capable of describing the alveolar bone remodeling. Thus, 2 different models were developed. The first is based on the assumption that deformations of the periodontal ligament (PDL) are the key stimulus to starting orthodontic tooth movement. The second supposes that deformations of the alveolar bone are the basis of orthodontic bone remodeling. Both models were integrated into a finite element package calculating stresses, strains and deformations of tooth and tooth supporting structures and from this simulating the movement of the tooth and its alveolus through the bone. Clinically induced canine retractions in 5 patients as well as force systems were exactly measured and the tooth movements were simulated using both models. The results show that the first model allows reliable simulation of orthodontic tooth movements, whereas the second is to be rejected. PMID:10220981

Bourauel, C; Freudenreich, D; Vollmer, D; Kobe, D; Drescher, D; Jäger, A

1999-01-01

400

Identification and rock failure characterization in bit-tooth penetration  

Microsoft Academic Search

The invariant imbedding identification technique is used to estimate bit-rock parameters and an unknown state variable required in a previous rock model applied to a tooth drop test. This rock description characterizes the state of interaction between the rock and bit-tooth in terms of the instantaneous force and velocity at their interface. Although 2 of the needed parameters - the

Umez-Eronini

1983-01-01

401

Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel  

Microsoft Academic Search

This thesis deals with advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum

Rao F. H. Khan

2003-01-01

402

Evaluation of Healing Following Tooth Extraction With Ridge Preservation Using Cortical Versus Cancellous Freeze Dried Bone Allograft.  

PubMed

Background: The objective of this study is to compare histologic and clinical healing following tooth extraction and ridge preservation with either cortical or cancellous freeze-dried bone allograft (FDBA) in non-molar extraction sockets. Methods: Forty patients requiring implant placement were enrolled, with 20 patients randomly assigned to each group (cortical vs. cancellous FDBA). All of the allograft materials were obtained from the same donor to control for variability between donors and processing. Patients returned after 17-21 weeks (average 18.2 weeks) and a 2mm diameter core biopsy was obtained prior to implant placement. Histomorphometric analysis was performed to determine percent of new bone formation, residual graft material, and nonmineralized connective tissue (CT)/other material. Clinical measurements of ridge dimensions were taken at the time of tooth extraction and again at implant placement. Results: There was no significant difference in new bone formation between the cortical and cancellous FDBA groups (p=0.857). A significantly greater percentage of residual graft material was detected in the cortical FDBA group as compared to the cancellous FDBA group (p=0.019). A significantly greater percentage of nonmineralized CT/other material was found in the cancellous FDBA group as compared to the cortical FDBA group (p=0.040). The only significant clinical difference between groups was a greater loss of lingual ridge height in the cancellous group. Conclusions: This is the first reported study to compare the histological changes following tooth extraction with ridge preservation in humans using cortical vs. cancellous FDBA. There were no differences in the percentage of new bone formation between the groups. PMID:23725026

Eskow, Adam J; Mealey, Brian L

2013-05-31

403

Indigenous hydroxyapatite coated and bioactive glass coated titanium dental implant system - Fabrication and application in humans  

PubMed Central

Background: The use of different bioactive materials as coating on dental implant to restore tooth function is a growing trend in modern Dentistry. In the present study, hydroxyapatite and the bioactive glass-coated implants were evaluated for their behavior in osseous tissue following implantation in 14 patients. Materials and Methods: Bioactive glass and hydroxyapatite formulated and prepared for coating on Ti-6Al-4V alloy. Hydroxyapatite coating was applied on the implant surface by air plasma spray technique and bioactive glass coating was applied by vitreous enameling technique. Their outcome was assessed after 6 months in vivo study in human. Results: Hydroxyapatite and bioactive glass coating materials were nontoxic and biocompatible. Uneventful healing was observed with both types of implants. Conclusion: The results showed bioactive glass is a good alternative coating material for dental implant.

Mistry, Surajit; Kundu, Debabrata; Datta, Someswar; Basu, Debabrata; Soundrapandian, Chidambaram

2011-01-01

404

Zygoma implant-supported prosthetic rehabilitation after partial maxillectomy using surgical navigation: a clinical report.  

PubMed

The rehabilitation of patients with acquired defects of the maxilla is a challenge in terms of reestablishing oronasal separation. In most patients these goals are met by means of prosthetic rehabilitation with an obturator prosthesis. If the remaining dentition does not offer sufficient retention and support, the placement of zygoma implants can enhance the stability of the prosthesis. Due to the anatomic intricacies of the zygomatic bone and the implant length, computer-supported navigated implant placement can be advantageous. In the following clinical report, a diabetic patient with a status of posthemimaxillectomy secondary to aspergillusis infection is presented, in whom a zygoma implant was placed using a CT scan-based navigation system. A special retentive anchoring abutment was used to integrate the zygoma implant into a telescopic crown-retained denture on the residual dentition. This tooth-implant-supported obturator prosthesis restored function and phonetics, as well as esthetics, for this young patient. PMID:17394908

Kreissl, Marion E; Heydecke, Guido; Metzger, Marc C; Schoen, Ralf

2007-03-01

405

Reattachment of complicated tooth fracture: An alternative approach  

PubMed Central

Trauma to the anterior teeth is relatively a common occurrence. There are several treatment modalities for such condition, one of which is reattachment of fractured fragment itself. Reattachment of fractured fragment provides immediate treatment with better esthetics, restoration of function, and is a faster and less complicated procedure. Reattachment of tooth fragment should be the first choice and is a viable alternative to conventional approaches because of simplicity, natural esthetics, and conservation of tooth structure. Patient cooperation and understanding of the limitations of the treatment is of utmost importance for good prognosis. The present case report describes management of a complicated fracture of maxillary right central incisor treated endodontically, followed by reattachment of the same fragment. Reattachment of fractured tooth fragments offers a viable restorative alternative, immediately restores tooth function for the clinician because it restores tooth function and esthetics with the use of a very conservative and cost-effective approach.

Kumari, Nujella B. P. Surya; Sujana, V.; Sunil, C. H. Ram; Reddy, P. Satyanarayana

2012-01-01

406

Prosthodontic rehabilitation of malpositioned implants after ameloblastoma followed by mandibulectomy and costal bone graft: a clinical report.  

PubMed

This clinical report describes the rehabilitation with costal bone graft reconstruction and 3 implants of a patient with a partial mandibular defect as a result of a partial mandibulectomy due to ameloblastoma of the left mandible. Due to the altered shape of the graft bone, the implants were malpositioned in the buccolingual plane. The prosthodontic rehabilitation was successfully completed by using an implant-supported milled bar combined with telescopic crown-retained dentures. This tooth implant-supported prosthesis successfully restored function and esthetics. Aspects that deal with the repair of the buccal soft tissues are discussed. PMID:23287980

Wang, Wei; Mao, Cai-Yun; Gu, Xin-Hua

2013-02-01

407

Peri-implant soft tissue conditioning with provisional restorations in the esthetic zone: the dynamic compression technique.  

PubMed

An optimal esthetic implant restoration is a combination of a visually pleasing prosthesis and surrounding peri-implant soft tissue architecture. This article introduces a clinical method, the dynamic compression technique, of conditioning soft tissues around bone-level implants with provisional restorations in the esthetic zone. The technique has several goals: to establish an adequate emergence profile; to recreate a balanced mucosa course and level in harmony with the gingiva of the adjacent teeth, including papilla height/width, localization of the mucosal zenith and the tissue profile's triangular shape; as well as to establish an accurate proximal contact area with the adjacent tooth/implant crown. PMID:23820704

Wittneben, Julia-Gabriela; Buser, Daniel; Belser, Urs C; Brägger, Urs

408

Asyndromic hypodontia associated with tooth morphology alteration: A rare case report.  

PubMed

Clinicians frequently encounter hypodontia in their practice. It can be associated with any syndrome or more commonly it is asyndromic. This asyndromic form is commonly familial and can be followed in heredity of the patient. The patient referred in this report presented with a rare anomaly of hypodontia with altered morphology where the patient had all the teeth single rooted and single canalled. Studies have indicated several genes that affect the tooth morphology and number. A genetic correlation of hypodontia with altered permanent teeth morphology may be explored further in studies. PMID:23833465

Agarwal, Abhinay; Gundappa, Mohan; Miglani, Sanjay; Nagar, Rohit

2013-05-01

409

Preserved irradiated homologous cartilage implants in canine eyelids  

SciTech Connect

Preserved irradiated homologous costal cartilage implants were placed in six canine lower lids for a period of 7-12 weeks. The three implants placed under a covering of conjunctiva simulating current clinical technique were well tolerated and demonstrated little change. Exposed implants produced obvious clinical inflammation and two of three exposed grafts disappeared during the 4- to 5-week interval. The single exposed implant that was retained demonstrated partial epithelialization but suffered extensive absorption and remodeling.

Schenk, W.; Linberg, J.V.; McCormick, S. (West Virginia Univ. School of Medicine, Morgantown (USA))

1985-01-01

410

Implantable Medical Devices  

MedlinePLUS

Implantable Medical Devices Updated:May 1,2012 In certain cases, your doctor may prescribe an implantable device to assist your ... maintain the pumping ability of your heart. Implantable Medical Devices Left Ventricular Assist Device (Also known as LVAD) ...

411

Implant-Supported Denture  

MedlinePLUS

... to implants. A regular denture rests on the gums, and is not supported by implants. An implant- ... supported denture daily to clean the denture and gum area. Just as with regular dentures, you should ...

412

Dental implants in patients with Ehlers-Danlos syndrome: a case series study.  

PubMed

Ehlers-Danlos syndrome (EDS) encompasses six types of hereditary connective tissue disorders, with skin hyperextensibility, joint hypermobility, and connective tissue fragility as the main findings. Oral health is also affected, sometimes including periodontitis and tooth loss. This is the first report on dental implant treatment for patients with hypermobility or classic EDS. Five female patients aged 19 to 68 years who tolerated treatment under local anesthesia and did not require bone augmentation were enrolled in the study and received 16 implants. They were observed for 2 to 12 years. No implants were lost, bone loss was minimal, and all patients were pleased with the treatment outcomes. PMID:22259798

Jensen, Janicke Liaaen; Storhaug, Kari

413

Forced orthodontic eruption for augmentation of soft and hard tissue prior to implant placement  

PubMed Central

Forced orthodontic eruption (FOE) is a non-surgical treatment option that allows modifying the osseous and gingival topography. The aim of this article is to present a clinical case of a FOE, which resulted in an improvement of the amount of available bone and soft-tissues for implant site development. Patient was referred for treatment of mobility and unesthetic appearance of their maxillary incisors. Clinical and radiographic examination revealed inflamed gingival tissue, horizontal and vertical tooth mobility and interproximal angular bone defects. It was chosen a multidisciplinary treatment approach using FOE, tooth extraction, and immediate implant placement to achieve better esthetic results. The use of FOE, in periodontally compromised teeth, promoted the formation of a new bone and soft-tissue in a coronal direction, without additional surgical procedures, enabling an esthetic, and functional implant-supported restoration.

de Molon, Rafael Scaf; de Avila, Erica Dorigatti; de Souza, Joao Antonio Chaves; Nogueira, Andressa Vilas Boas; Cirelli, Carolina Chan; Margonar, Rogerio; Cirelli, Joni Augusto

2013-01-01

414

Unusual intraosseous transmigration of impacted tooth  

PubMed Central

Transmigration of an impacted tooth through the symphyseal suture is a rare and special developmental anomaly of unknown etiology that is unique to the mandibular canine. Maxillary canine transmigration is even rarer. Transmigrated canines are particularly significant due to the aesthetic and functional importance. A maxillary lateral incisor crossing the mid-palatal suture has never been reported in the literature. The aim of this report is to present the first case of simultaneous transmigration of a lateral incisor and canine in the maxilla. The paper also reports four unusual cases of unilateral canine transmigration in the maxilla and mandible and successful eruption of one of the transmigrated mandibular canines following orthodontic traction. Etiology of transmigration and its clinical considerations are also discussed.

Urala, Arun Srinivas; Kamath, Abhay Taranath; Jayaswal, Priyanka; Valiathan, Ashima

2012-01-01

415

A comparison of the implant stability among various implant systems: clinical study  

PubMed Central

PURPOSE To determine the change in stability of single-stage, three different design of implant systems in humans utilizing resonance frequency analysis for early healing period (24 weeks), without loading. MATERIAL AND METHODS Twenty-five patients were included into this study. A total of 45 implants, three different design of implant systems (group A,C,R) were placed in the posterior maxilla or mandible. The specific transducer for each implant system was used. ISQ (implant stability quotient) reading were obtained for each implant at the time of surgery, 3, 6, 8, 10, 12, 24 weeks postoperatively. Data were analyzed for different implant type, bone type, healing time, anatomical locations. RESULTS For each implant system, a two-factor mixed-model ANOVA demonstrated that a significant effect on ISQ values (group A = 0.0022, C = 0.017, R = 0.0018). For each implant system, in a two-factor mixed model ANOVA, and two-sample t-test, the main effect of jaw position (P > .005) on ISQ values were not significant. CONCLUSIONS All the implant groups A, C and R, the change patterns of ISQ over time differed by bone type. Implant stability increased greatly between week 0 and week six and showed slow increase between week six and six months (plateau effect).

Kim, Jae-Min; Kim, Sun-Jong; Han, Inho; Shin, Sang-Wan

2009-01-01

416

Case presentation of florid cemento-osseous dysplasia with concomitant cemento-ossifying fibroma discovered during implant explantation.  

PubMed

A 39-year-old African American woman presented for treatment of a symptomatic mandibular right first molar with a large, periapical radiolucency. After initial attempts at endodontic therapy, this tooth was ultimately extracted owing to unabated symptoms. The extraction site underwent ridge preservation grafting, implant placement, and restoration. After 26 months of implant function, the patient returned with clinical symptoms of pain, buccal swelling, and the sensation of a "loose" implant. This case report details a diagnosis of 2 distinct disease entities associated with the implant site, a cemento-ossifying fibroma and florid cemento-osseous dysplasia of the mandible. This diagnosis was determined from clinical, surgical, radiographic, and histopathologic evidence after biopsy and removal of the previously osseointegrated implant following postinsertion failure by fibrous encapsulation. Before implant therapy, it is essential to conduct a thorough radiographic evaluation of any dental arch with suspected bony lesions to prevent implant failure. PMID:22858018

Gerlach, Robert C; Dixon, Douglas R; Goksel, Tamer; Castle, James T; Henry, Walter A

2012-08-02

417

Tooth loss and obstructive sleep apnoea  

PubMed Central

Background Complete tooth loss (edentulism) produces anatomical changes that may impair upper airway size and function. The aim of this study was to evaluate whether edentulism favours the occurrence of obstructive sleep apnoea (OSA). Methods Polysomnography was performed in 48 edentulous subjects on two consecutive nights, one slept with and the other without dentures. Upper airway size was assessed by cephalometry and by recording forced mid-inspiratory airflow rate (FIF50). Exhaled nitric oxide (eNO) and oral NO (oNO), were measured as markers of airway and oropharyngeal inflammation. Results The apnoea/hypopnoea index (AHI) without dentures was significantly higher than with dentures (17·4 ± 3·6 versus 11·0 ± 2·3. p = 0·002), and was inversely related to FIF50 (p = 0·017) and directly related to eNO (p = 0·042). Sleeping with dentures, 23 subjects (48%) had an AHI over 5, consistent with OSA, but sleeping without dentures the number of subjects with abnormal AHI rose to 34 (71%). At cephalometry, removing dentures produced a significant decrease in retropharyngeal space (from 1·522 ± 0·33 cm to 1·27 ± 0·42 cm, p = 0·006). Both morning eNO and oNO were higher after the night slept without dentures (eNO 46·1 ± 8·2 ppb versus 33·7 ± 6·3 ppb, p = 0·035, oNO 84·6 ± 13·7 ppb versus 59·2 ± 17·4 ppb, p = 0·001). Conclusion These findings suggest that complete tooth loss favours upper airway obstruction during sleep. This untoward effect seems to be due to decrease in retropharyngeal space and is associated with increased oral and exhaled NO concentration.

Bucca, Caterina; Cicolin, Alessandro; Brussino, Luisa; Arienti, Andrea; Graziano, Alessandra; Erovigni, Francesco; Pera, Paolo; Gai, Valerio; Mutani, Roberto; Preti, Giulio; Rolla, Giovanni; Carossa, Stefano

2006-01-01

418

Pretty painful: why does tooth bleaching hurt?  

PubMed

Vital bleaching procedures are a popular means of improving the appearance of discolored teeth. There is a wide array of whitening products for home and dental office use; all involves placing peroxide containing gels or solutions in contact with the teeth. In order to whiten teeth peroxide has to be able to penetrate tooth structure and oxidize colored compounds in the dentin. Unfortunately beauty comes with a price; many patients undergoing peroxide based whitening procedures complain of bleaching sensitivity (BS) arising in the treated teeth. In BS, pain can occur in healthy intact teeth without any provoking stimulus. Currently the mechanism of nociceptors activation in BS is unknown. A more common form of dental pain-dentin sensitivity (DS) occurs when stimuli such as cold or tactile stimulation contact areas of exposed dentin in otherwise healthy teeth. In DS, stimulation of the dentin results in fluid shifts in the dentinal tubules, these fluid shifts activate mechanosensitive nerve endings in the deep dentin and pulp. Since many aspects of BS and DS symptoms differ, it is hypothesized that that the mechanism of pain generation differs for these two conditions. Recently the functional properties of a chemosensitive ion channel-TRPA1 have been described. This channel is activated by a variety of oxidizer compounds including hydrogen peroxide. Pulpal sensory afferents express TRPA1. It is hypothesized that direct activation of intradental nerve activity via TRPA1 is the mechanism of BS pain. If this theory were correct, tooth sensitivity treatments that reduce the excitability of the intradental nerves such as potassium salts, would be the treatment of choice for BS. PMID:20045265

Markowitz, Kenneth

2009-12-31

419

Combined Intacs and Posterior Chamber Toric Implantable Collamer Lens Implantation for Keratoconic Patients with Extreme Myopia  

Microsoft Academic Search

? PURPOSE: To evaluate the results of combined Intacs (Addition Technology, Fremont, California, USA) and posterior chamber toric implantable Collamer lens (ICLs) (Visian ICL; STAAR Surgical, Monrovia, California, USA) implantation in keratoconic patients with extreme myopia and irregular astigmatism. ? DESIGN: Prospective, single-center, noncomparative, interventional, consecutive case series. ? METHODS: Three eyes of two consecutive highly my- opic keratoconic patients

EFEKAN COSKUNSEVEN; METHIYE ONDER; GEORGE D. KYMIONIS; VASILIOS F. DIAKONIS; EBRU ARSLAN; NIKOLAOS TSIKLIS; DIMITRIOS I. BOUZOUKIS; IOANNIS PALLIKARIS

2007-01-01

420

Proximity gettering with mega-electron-volt carbon and oxygen implantations  

Microsoft Academic Search

We have demonstrated that a buried gettering layer can be formed with a single MeV ion implantation without damaging the top device region. The strong gettering efficiency of carbon implant and its linear dependence on dose are confirmed. A surprising feature of the carbon implanted layers is that no extended defects are formed after annealing for implant doses up to

H. Wong; N. W Cheung; P. K. Chu; J. Liu; J. W. Mayer

1988-01-01

421

A time for change of tooth numbering systems.  

PubMed

Tooth numbering provides dentists with an essential shortcut in clinical record-keeping. Today, three systems are favored worldwide: the Zsigmondy/Palmer system, the universal system, and the FDI two-digit system. Histories of these tooth numbering methods are traced, and the strengths and deficiencies of each are discussed. The FDI two-digit system-used throughout the world, but not in the USA-is the only method that makes visual sense, cognitive sense, and computer sense. It deserves consideration by American dentists as our official tooth numbering system. PMID:8349894

Peck, S; Peck, L

1993-08-01

422

Unique case of a geminated supernumerary tooth with trifid crown  

PubMed Central

Gemination, a relatively uncommon dental anomaly, is characterized by its peculiar representation as a tooth with a bifid crown and a common root and root canal. It usually occurs in primary dentition. To come across gemination in a supernumerary tooth is a rare phenomenon. The purpose of this paper is to present a unique case of hyperdontia wherein gemination in an impacted supernumerary tooth resulted in a trifid crown unlike the usual bifid crown. The role of conventional radiographs as well as computed tomography, to accurately determine the morphology and spatial location, and to arrive at a diagnosis, is also emphasized in this paper.

Ather, Hunaiza; Sheth, Sanket Milan; Muliya, Vidya Saraswathi

2012-01-01

423

Assessment of demographic and clinical data related to dental implants in a group of Turkish patients treated at a university clinic  

PubMed Central

PURPOSE This retrospective study analyzed the distribution of the dental implants with regards to age and gender of the patients and type of indication for the implant therapy, as well as the location, dimension and type of the implants. MATERIALS AND METHODS The data of demographics (age and gender), type of indication for implant therapy, anatomical location, dimensions (length and diameter) and type (bone and tissue level) of 1616 implants were recorded from patient charts between January 2000 and January 2010. Descriptive statistics were analyzed using a chi-squared test for demographic parameters, type of indication, tooth position, anatomical location, implant dimensions and type (?=.05). RESULTS The patient pool comprised of 350 women and 266 men, with a mean age of 52.12 ± 13.79 years. The difference in n% of the implants of the age groups was statistically significant between the types of indications. The difference in the position of the implants was statistically significant between the n% of the implants of all age groups. Gender did not significantly vary, except that the diameter of the implants was significantly higher for the standard diameter implants in males. The difference between the implant positions was statistically significant when considered according to indication. The relationship between implant length and anatomical location was statistically significant. CONCLUSION The indication for dental implant use is age dependent and the type and size of the implant seems to be strongly related to the location of the implant.

Bural, Canan; Bilhan, Hakan; Cilingir, Altug

2013-01-01

424

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

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

2010-01-01

425

Determination of the ISO tooth form factor for involute spur and helical gears  

Microsoft Academic Search

To estimate the bending stress at the root of a loaded gear tooth, ISO\\/TC-60 introduced the tooth form factor and the stress concentration factor, which were both defined as a function of the tooth thickness at the critical section and the distance between this section and the intersection of the line of action and the tooth centerline, when load acts

J. I. Pedrero; A. Rueda; A. Fuentes

1999-01-01

426

Dynamic interaction between contact loads and tooth wear of engaged plastic gear pairs  

Microsoft Academic Search

This study investigates the interaction between the dynamic contact load and the tooth profile wear of POM and Nylon 66 plastic gear pairs. A dynamic model of a plastic gear pair is presented. This model incorporates the effects of position-varying tooth mesh stiffness, damping ratio, load sharing, tooth profile wear and temperature on the dynamic contact load. The tooth wear

Ah-Der Lin; Jao-Hwa Kuang

2008-01-01

427

Dynamic modeling and analysis of a spur planetary gear involving tooth wedging and bearing clearance nonlinearity  

Microsoft Academic Search

Tooth wedging, also known as tight mesh, occurs when a gear tooth comes into contact on the drive-side and back-side simultaneously. Tooth wedging risks bearing failures from elevated forces. This work studies the nonlinear tooth wedging behavior and its correlation with planet bearing forces by analyzing the dynamic response of an example planetary gear. This planetary gear is representative of

Yi Guo; Robert G. Parker

2010-01-01

428

Retrograde peri-implantitis  

PubMed Central

Retrograde peri-implantitis constitutes an important cause for implant failure. Retrograde peri-implantitis may sometimes prove difficult to identify and hence institution of early treatment may not be possible. This paper presents a report of four cases of (the implant placed developing to) retrograde peri-implantitis. Three of these implants were successfully restored to their fully functional state while one was lost due to extensive damage. The paper highlights the importance of recognizing the etiopathogenic mechanisms, preoperative assessment, and a strong postoperative maintenance protocol to avoid retrograde peri-implant inflammation.

Mohamed, Jumshad B.; Shivakumar, B.; Sudarsan, Sabitha; Arun, K. V.; Kumar, T. S. S.

2010-01-01

429

Relationship between natural tooth shade and skin colour.  

PubMed

The purpose of this study was to assess the correlation of skin colour and tooth shade. One hundred and twenty six individuals aging between 18 to 25 years participated in this study. Colour of the maxillary central incisors was examined by VITA easy shade. Tooth shades were assigned to four ordinal values. Nivea Beauty Protect Foundation shade sample was used as a guide to assess facial skin colour Shin colours were also assigned to four ordinal values. Spearman test revealed that there was a significant relationship between tooth shade and skin colour Total co-relation factor was 51.6% (p <0 .01). Co-relation factors were 57% for women and 27% for men (p <0 .01). The highest tooth shade prevalence belonged to the second group and the highest skin colour prevalence was also in the second skin colour group. PMID:23888526

Nourbakhsh, M; Mousavinejad, N; Adli, A R; Harati, M

2013-06-01

430

Generation of Gear Tooth Surfaces by Application of CNC Machines.  

National Technical Information Service (NTIS)

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. ...

F. L. Litvin N. X. Chen

1994-01-01

431

Income inequality and tooth loss in the United States.  

PubMed

This study explored the relationship between state income inequality and individual tooth loss among 386,629 adults in the United States who participated in the 2008 Behavioral and Risk Factor Surveillance System. Multilevel models were used to test the association of the state Gini coefficient with