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Sample records for single tooth implant

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2014-05-01

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

  3. Meta-analysis of Failure and Survival Rate of Implant-supported Single Crowns, Fixed Partial Denture, and Implant Tooth-supported Prostheses

    PubMed Central

    Muddugangadhar, B C; Amarnath, G S; Sonika, Radhika; Chheda, Pratik S; Garg, Ashu

    2015-01-01

    Background: Dental implants have become the most viable option for rehabilitation. Although, many studies report the success of these reconstructions using implants, a cumulative data about the various studies and the failure rate still remain unaddressed. Therefore, the purpose of this systematic review was to analyze these data and to derive the cumulative survival rate of different implant-supported prosthesis. Materials and Methods: Manual searches followed by a MEDLINE search were conducted to select prospective and retrospective cohort studies on single crowns (SCs), fixed partial denture (FPD), and tooth implant connected prostheses with a mean follow-up time of minimum of 5 years. Random-effects Poisson’s regression models have been used to obtain summary estimates for implant failure and survival rates. Results: Data were extracted from the final selected 63 studies. In a meta-analysis of these studies, the survival rate of SCs supported by implants (95% CI) was 96.363%, for FPDs was 94.525% and implant tooth-supported prostheses was 91.27% after 5 years of function. The cumulative failure rate per 100 FPD years of the SCs, FPDs, and implant tooth-supported prostheses were 0.684, 0.881, and 1.514, respectively. Conclusion: The study concludes high survival rates for implant-supported SCs followed by implant-supported FPDs can be expected over an observation period of 5 years. However, tooth implant-supported prostheses can be provided if there are certain limitations prohibiting the completely implant-supported prostheses. PMID:26435609

  4. Long-term cumulative survival and mechanical complications of single-tooth Ankylos Implants: focus on the abutment neck fractures

    PubMed Central

    2015-01-01

    PURPOSE To evaluate the cumulative survival rate (CSR) and mechanical complications of single-tooth Ankylos® implants. MATERIALS AND METHODS This was a retrospective clinical study that analyzed 450 single Ankylos® implants installed in 275 patients between December 2005 and December 2012. The main outcomes were survival results CSR and implant failure) and mechanical complications (screw loosening, fracture, and cumulative fracture rate [CFR]). The main outcomes were analyzed according to age, sex, implant length or diameter, bone graft, arch, and position. RESULTS The 8-year CSR was 96.9%. Thirteen (2.9%) implants failed because of early osseointegration failure in 3, marginal bone loss in 6, and abutment fracture in 4. Screw loosening occurred in 10 implants (2.2%), and 10 abutment fractures occurred. All abutment fractures were located in the neck, and concurrent screw fractures were observed. The CSR and rate of screw loosening did not differ significantly according to factors. The CFR was higher in middle-aged patients (5.3% vs 0.0% in younger and older patients); for teeth in a molar position (5.8% vs 0.0% for premolar or 1.1% for anterior position); and for larger-diameter implants (4.5% for 4.5 mm and 6.7% for 5.5 mm diameter vs 0.5% for 3.5 mm diameter) (all P<.05). CONCLUSION The Ankylos® implant is suitable for single-tooth restoration in Koreans. However, relatively frequent abutment fractures (2.2%) were observed and some fractures resulted in implant failures. Middle-aged patients, the molar position, and a large implant diameter were associated with a high incidence of abutment fracture. PMID:26813443

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

    PubMed Central

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

    2014-01-01

    The aim of this study was to achieve aesthetically pleasing soft tissue contours in a severely compromised tooth in the anterior region of the maxilla. For a right-maxillary central incisor with localized advanced chronic periodontitis a tooth extraction followed by reconstructive procedures and delayed implant placement was proposed and accepted by the patient. Guided bone regeneration (GBR) technique was employed, with a biphasic calcium-phosphate (BCP) block graft placed in the extraction socket in conjunction with granules of the same material and a resorbable barrier membrane. After 6 months of healing, an implant was installed. The acrylic provisional restoration remained in situ for 3 months and then was substituted with the definitive crown. This ridge reconstruction technique enabled preserving both hard and soft tissues and counteracting vertical and horizontal bone resorption after tooth extraction and allowed for an ideal three-dimensional implant placement. Localized severe alveolar bone resorption of the anterior maxilla associated with chronic periodontal disease can be successfully treated by means of ridge reconstruction with GBR and delayed implant insertion; the placement of an early-loaded, Morse taper connection implant in the grafted site was effective to create an excellent clinical aesthetic result and to maintain it along time. PMID:25431687

  6. Ankylosed maxillary incisor with severe root resorption treated with a single-tooth dento-osseous osteotomy, vertical alveolar distraction osteogenesis, and mini-implant anchorage.

    PubMed

    Sen???k, Neslihan Ebru; Koer, Glperi; Kaya, Bulem reyen

    2014-09-01

    Dentoalveolar ankylosis interferes with the vertical growth of the alveolar process, which can lead to an open bite, an unesthetic smile, and occlusal disharmony. This case report presents a new treatment protocol for an ankylosed tooth with severe root resorption using a combined surgical orthodontic management protocol involving a single-tooth dento-osseous osteotomy and vertical alveolar distraction osteogenesis with intraoral elastics and mini-implant anchorage. After distraction and active orthodontic treatment, the patient's anterior open bite was corrected. A Class I dental relationship was achieved, overjet was decreased, and a normal incisor relationship was obtained. PMID:25172260

  7. A custom titanium implant-retained single-tooth restoration: a clinical report.

    PubMed

    Schmitt, S M; Chance, D A

    1996-01-01

    Titanium is an inexpensive metal that can be used to create custom cast restorations. Although special investment and casting equipment is needed to make titanium castings, the potential benefit of inexpensive, biocompatible, and custom restorations is significant. Porcelain can easily be applied to titanium with excellent bond strength and esthetics. Problems associated with casting roughness and fit can be corrected using electrical discharge machining. A method of diagnosis and treatment planning that evaluates the restorative space prior to implant placement and eliminates the use of machined components is presented. PMID:8990641

  8. Implants for single-tooth replacement. A clinical and experimental study on the Brånemark CeraOne System.

    PubMed

    Andersson, B

    1995-01-01

    The general aim of the thesis was to study single-tooth replacements with implants using a recently developed prosthodontic concept, CeraOne. More specifically, the aims were to present prosthodontic procedures and early clinical experiences of CeraOne, and to study the following: the acceptance and the rejection of referred patients, the mechanical strength of the complete implant post and of superstructures on the CeraOne abutment, the treatment outcome from an on-going prospective clinical investigation, the effect of guided tissue regeneration when using e-PTFE membranes in narrow alveolar ridges, and finally, the outcome from treatments by general practitioners (GPs) who had performed the complete care of the single-tooth patient. The acceptance and the rejection of patients were studied on 184 patients, and the conclusions were based on data from referral, case history, clinical examination, and therapy planning. External trauma, root fractures, and congenitally missing teeth were the main reasons for lost or missing teeth in referred patients, while anatomical limitations were the most frequent reasons for the rejections. The mechanical strength was determined after testing in an Instron universal testing machine. The abutment screw was shown to be the weakest link, while a satisfactory safety margin against fractures was observed for the metal-ceramic and the all-ceramic crowns. It was also shown that the all-ceramic ¿ crown could resist bending moments up to a level that was more than three times as high as the one at which the porcelain crown fractured. In the clinical prospective study, the results from treatments of 57 patients (65 implants) were reported after two years and from 34 patients (37 implants) after three years. Favourable survival rates were shown for the implants (97.3% at 3-4 years) and, as a mean, only a small bone loss around the implants and the adjacent teeth was observed. The conical implants, however, showed a higher degree of bone los in comparison to the other implants. The CeraOne prosthodontic concept was simple to sue because of prefabricated components, and favourable aesthetic and clinical short-term results were achieved. Problems of screw loosening and fistulas were avoided and the cementation of the crown and the subgingival placement of the abutment shoulder did not cause any soft tissue recession. Fifteen patients (20 implants) with a suspected need of guided tissue regeneration were selected for the study using e-PTFE membranes. After treatment and at the second stage surgery, it was shown that most of the primarily exposed implant surfaces at this time were covered by a newly formed tissue with signs of osteoid activity.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7644974

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

    PubMed Central

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

    2014-01-01

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

  10. Effects of Antibiotics on Bone and Soft-Tissue Healing Following Immediate Single-Tooth Implant Placement Into Sites With Apical Pathology.

    PubMed

    Hosseini, Bashir; Byrd, Warren C; Preisser, John S; Khan, Asma; Duggan, Derek; Bencharit, Sompop

    2015-10-01

    Overprescription of antibiotics can cause bacterial resistance problems, leading to life-threatening illnesses and public health crises. Clinicians often believe antibiotics can prevent dental implant failure and postoperative complications. In conjunction with implant surgery, antibiotics are therefore routinely prescribed for all cases. In this double-blind, randomized controlled trial, the effects of antibiotics on the clinical outcomes of immediate implant placement upon replacing a tooth with an apical pathology were examined to compare antibiotics (n = 10) and placebo (n = 10). In each subject, a tooth with a chronic apical lesion was extracted, thoroughly curetted, irrigated, and replaced with single implant with a screw-retained custom provisional abutment/crown. Postoperative pain/discomfort was measured at 1- and 4-week postsurgical follow-up visits using visual analog scales. Facial alveolar bone and soft-tissue changes were measured using pre- and postoperative cone-beam computerized tomography and impressions. We found survival rates of 100% (antibiotics) and 78% (control). However, there was no statistical difference in means for any clinical outcome (t tests with Bonferroni adjustment for multiple testing), except for midfacial soft-tissue changes: 0.43 mm (SD, 0.76) in the antibiotics group and 1.70 mm (SD, 1.06) in the placebo group (t15 = -2.89, P = .011). The average change of the midfacial alveolar plate was 0.62 mm (SD, 0.46) and 1.34 mm (SD, 0.91) for the antibiotic and placebo groups, respectively, which did not significantly differ statistically. No significant correlation (Spearman correlation) existed between the changes in facial alveolar bone and the facial gingival margin. Antibiotics appear to have little effect on immediate implant treatment outcomes. PMID:25076118

  11. Socket seal surgery: Clinical uses in implant dentistry and guided bone regeneration procedures for single tooth replacement in the esthetic zone.

    PubMed

    Negri, Bruno; Zuhr, Otto; Fickl, Stefan; Ciurana, Xavier Rodrguez; Navarro Martnez, Jos Manuel; Blanco, Vctor Mndez

    2016-01-01

    Restoring failing anterior teeth with a dental implant is considered a complex treatment even with thorough biologic knowledge of the situation. The goal is to produce a result in which the labial soft tissues and the papillae remain stable over time. Treatment of the fresh extraction socket in the alveolar ridge presents a challenge in everyday clinical practice. Regardless of the subsequent treatment, maintenance of the ridge contour will frequently facilitate all further therapeutic steps. Socket seal surgery and socket preservation in combination with immediate, early, or delayed implant placement can be valuable procedures for single tooth replacement. However, their potential as ridge preservation techniques in these different situations still needs to be demonstrated. The use of these procedures is illustrated in three consecutive cases. PMID:26159209

  12. Surgical and prosthodontic training of general practitioners for single tooth implants: a study of treatments performed at four general practitioners' offices and at a specialist clinic after 2 years.

    PubMed

    Andersson, B; Odman, P; Lindvall, A M; Brnemark, P I

    1995-08-01

    Both the surgical and the prosthodontic procedures will be performed by one and the same general practitioner (GP) for many implant patients, as access to specialists is limited or non-existent in a large number of places. However, treatment by GPs has not been documented to the same extent as treatment performed by specialists. This lack of knowledge was the reason for the present study, in which four GPs performed both the surgery and the prosthodontics on patients requiring single tooth implant replacements. The treatments were performed after an initial training of the GP and his/her dental assistant for 8 days. The treatments by the GPs exhibited clinical results corresponding to those achieved at a specialist clinic. The outcome indicates that complete single tooth implant treatments might be performed by GPs who have passed an initial training and demonstrated an interest in a close co-operation with specialists in oral surgery/periodontics and prosthodontics. Such a co-operation should be based on the distribution of complicated cases to the specialists and of non-complicated cases to the GPs. PMID:7472723

  13. [A tooth or an implant--literature based decision making].

    PubMed

    Bar On, H; Sharon, E; Lipovezky-Adler, M; Haramaty, O; Smidt, A

    2014-07-01

    The common use of dental implants in the daily practice led to a profound change in the available treatment strategies. The option of replacing a diagnosed doubtful tooth with an implant has become widely accepted and often used. The prognosis systems in use today are based on the three major disciplines: endodontics, periodontics and prosthodontics. Combining these three may impair and bias the decision making process and increase the tendency to base it on subjective clinical experience and personal preference. Reading and reviewing the relevant literature gives no clear tool for use. Root canal treatment is considered a highly predictable treatment procedure and a treated tooth is affected mainly by the quality and type of the fabricated restoration and the risk of caries. Periodontal treatment followed by a suitable maintenance regimen will likely allow long term tooth survival. When comparing the success rates of natural teeth rehabilitation versus implant supported restorations, it appears that with implants an additional treatment is demanded along the years. This coincides with the fact that to date there is no consensus regarding the extent of perimplantitis and perimucositis that is to be expected around a restored implant. In addition, a peri implant tissue problem or a failure of a dental implant may prove to be more challenging than a failure of a tooth. It is important to remember that a dental implant is made to substitute a missing tooth and it is a treatment modality with known and clear indications for rehabilitation of an edentulous space. The aim of this paper is to review and discuss the various aspects of whether to maintain a compromised or a doubtful tooth or to prefer a treatment modality using dental implants. In conclusion it is advised here, to incorporate the discussed issues in the decision making process towards the most suitable treatment plan. PMID:25219096

  14. Prognosis and evaluation of tooth damage caused by implant fixtures

    PubMed Central

    Yoon, Wook-Jae; Jeong, Mi-Ae; Oh, Ji-Su; You, Jae-Seek

    2013-01-01

    Damage to adjacent teeth is one of the various complications that may occur during implant placement and is often the result of improper direction during fixture placement or excessive depth of placement. In general, if detrimental symptoms, such as reaction to percussion in damaged teeth, mobility, and pulp necrosis, are not present, osseointegration should be observed at follow-up. In three cases, the possibility of root damage due to an implant fixture placed too close to each adjacent tooth was perceived on radiographs. However, in all of these cases, there were no clinical symptoms or radiographic changes present in the tooth, and the implants did not exhibit decreased stability or peri-implantitis. Therefore, we can carefully predict that the implant fixture close to the adjacent tooth did not invade the cementum of the root, and therefore did not produce the suspected pulpal damage or periradicular symptoms. In this study, we considered both the implant status as well as the adjacent tooth. PMID:24471033

  15. [Provisional implants for immediate overdenture fixation after multiple tooth extraction].

    PubMed

    Gvetadze, R Sh; Krechina, E K; Myrochkin, V V; Korolev, V M

    2011-01-01

    The aim of the study was to assess the effectiveness of immediate overdenture supported by provisional mini-implants after multiple tooth extraction. The study included 39 patients aged 5517, followed up for 12 months. The first group included 14 patients with 65 mini-implants and 17 soft-lined immediate overdentures. In the second group (10 patients, 45 mini-implants) 12 immediate overdentures had hard liner. In the third group (15 patients) immediate overdentures with hard liner were used without implant support. 12-month implant survival was 98.5% in the I and 91.1% in the II group (1 and 4 implants failed correspondently). The number of denture basis corrections was minimal in the second group (2.90.46) and largest in the third group (4.320.67). Mini-implants provided better fixation of complete denture, facilitated mucosal adaptation to denture compared with immediate dentures without implant support. PMID:22433646

  16. Biomechanical considerations on tooth-implant supported fixed partial dentures

    PubMed Central

    Calvani, Pasquale; Hirayama, Hiroshi

    2012-01-01

    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. PMID:23255882

  17. Cemented and screw-retained implant-supported single-tooth restorations in the molar mandibular region: A retrospective comparison study after an observation period of 1 to 4 years

    PubMed Central

    Pearrocha-Diago, Miguel; Prades, Guillermo; Sola-Ruiz, Mara-Fernanda; Agustn-Panadero, Rubn

    2015-01-01

    Objectives: The aim of this study was to evaluate the survival and compare the appearance of different mechanical and biological complications, in screw-retained and cemented-retained single-tooth implant-supported restorations localized in the molar mandibular region, over a period of 1 to 4 years. Material and Methods: A retrospective study was carried out with a total of eighty implant-supported restorations, which were placed in eighty patients for prosthetic rehabilitation of a mandibular molar. Forty patients were rehabilitated with a cemented-retained restoration and the other forty with a screw-retained restoration. The presence of the following complications was recorded for both types of prostheses: Fractures of the ceramic veneering, loosening screws, mucositis and peri-implantitis. Debonding of the restoration was analyzed in the cemented-retained restoration group. The clinical survival of crowns was analyzed with a Kaplan-Meier test and the clinical complications were compared, using a Student t test and Log-rank test. Results: 27 patients registered some complication. The average rate of complications was 37,5% for cemented-retained restorations and 30% for screw-retained restorations. The complications more common in the cemented-retained restoration were the presence of mucositis (14,87%), while in the screw-retained restorations was the loosening screw (20%). Student t test and Log-Rank test found significant differences (p=0,001) between the screw loosening and presence of mucositis. Conclusions: The cemented-retained restorations seem to prevent screw loosening, but the presence of cement seem to increase the complications around the soft tissues, however in the screw-retained restorations the presence of mucositis and peri-implantitis are lower than cemented-retained restorations. The incidence of fracture of ceramic veneering was similar in both groups. Key words:Screw-retained restorations, cemented-retained restorations, screw loosening, peri-implant diseases and fracture ceramic veneering. PMID:25810850

  18. Rehabilitation using single stage implants

    PubMed Central

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

    2009-01-01

    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. PMID:20376239

  19. The management of traumatic tooth loss with dental implants: Part 1.

    PubMed

    Chesterman, J; Chauhan, R; Patel, M; Chan, M F W-Y

    2014-12-01

    Traumatic dental injuries are relatively common causes of emergency presentation to general dental practitioners. There are well established guidelines for the management of traumatised teeth, which practitioners should be familiar with and able to deliver. Some teeth, however, are either lost at the time of injury or are found to have a hopeless long-term prognosis despite appropriate treatment. The first article in this two-part series covers the important aspects of maintaining teeth where possible, to preserve the supporting hard and soft tissues. It then describes the replacement of a single tooth lost due to trauma and the relative challenges faced. The second article covers more extensive trauma, involving multiple teeth and where significant supporting tissues are lost. It describes the replacement of teeth, including the hard and soft tissues with implant supported restorations, whilst highlighting the need for a multidisciplinary team in severe cases. PMID:25476636

  20. Single-tooth restorations with a screw-retained, combined crown-and-abutment prosthesis.

    PubMed

    Obradovich, Robert N

    2008-09-01

    Screw retention for single-tooth restorations on dental implants is often advantageous, as it facilitates crown removal should an adverse event occur, or if modifications to the prosthesis design are anticipated. Prosthetic alterations can be problematic, however, if the screw access hole is not optimally placed to allow clinical access without compromising function or aesthetics. Contemporary nanocomposite materials are durable enough to function as definitive prostheses in the posterior region, and they may rival porcelain aesthetics intraorally to enable placement in the anterior region. This article presents a technique for fabricating an aesthetic, single-tooth restoration using nanocomposite materials and precontoured abutments to address potential concerns related to screw retention. PMID:18990897

  1. Autogenous tooth bone graft block for sinus augmentation with simultaneous implant installation: a technical note

    PubMed Central

    Lee, Kwang-Ho; Kim, Young-Kyun; Cho, Woo-Jin; Murata, Masaru; Mitsugi, Masaharu

    2015-01-01

    In cases of severe alveolar bone atrophy in the posterior maxillary area, which has only a thin sinus floor, the autogenous tooth bone graft block (ABTB) was used to wrap the implant to enhance its primary stability and osseointegration in the sinus. These cases with four years of clinical follow-up demonstrate the applicability of the ABTB in maxillary sinus membrane elevation to improve the outcomes of implant placement. PMID:26568934

  2. Autogenous tooth bone graft block for sinus augmentation with simultaneous implant installation: a technical note.

    PubMed

    Lee, Kwang-Ho; Kim, Young-Kyun; Cho, Woo-Jin; Um, In-Woong; Murata, Masaru; Mitsugi, Masaharu

    2015-10-01

    In cases of severe alveolar bone atrophy in the posterior maxillary area, which has only a thin sinus floor, the autogenous tooth bone graft block (ABTB) was used to wrap the implant to enhance its primary stability and osseointegration in the sinus. These cases with four years of clinical follow-up demonstrate the applicability of the ABTB in maxillary sinus membrane elevation to improve the outcomes of implant placement. PMID:26568934

  3. The teamwork approach to esthetic tooth replacement with immediate implant placement and immediate temporization.

    PubMed

    Levin, Barry P; Wilk, Brian L

    2015-10-01

    Enduring a period of edentulism between extraction and final restoration is difficult for patients- especially when it concerns the esthetic zone. The approach described demonstrates key points of consideration when replacing a maxillary anterior tooth with a dental implant using immediate implant placement, hard- and soft-tissue augmentation, and provisionalization. The authors stress adherence to patient selection and prosthetic design guidelines, and recommend the use of a digital impression technique, rather than traditional, rubber-based impressions. PMID:26448151

  4. Intrusion of teeth in the combination implant-to-natural-tooth fixed partial denture: a review of the theories.

    PubMed

    Pesun, I J

    1997-12-01

    This article reviews the literature dealing with the combination implant-to-natural-tooth-supported fixed partial denture. The restoration of masticatory function with a combination implant-to-natural-tooth fixed partial denture is associated with a variety of undesirable clinical sequelae, including the breakage of implant components, damage to the abutment teeth, or intrusion of the abutment teeth. Theories regarding intrusion of abutment teeth combined with implants for fixed partial dentures are only speculative. Several theories are presented to explain the intrusion of natural teeth in association with implant-to-natural-tooth fixed partial dentures. One of the first theories was based on the idea that a lack of normal stimulation of the periodontal ligament produces atrophy of the periodontal ligament and intrusion of the tooth. The remaining theories relate to excessive forces being placed on the natural tooth, resulting in movement of the tooth to a less stressful position. These forces are placed on the tooth by differential energy dissipation, mandibular flexion and torsion, flexion of the fixed partial denture framework, impaired rebound memory, debris impaction or microjamming, or ratchet effect related to the use of precision attachments. Based a review of the literature, a philosophy for treating combination implant-to-natural-tooth restorations is presented. PMID:9563327

  5. Peri-implant bone changes following tooth extraction, immediate placement and loading of implants in the edentulous maxilla.

    PubMed

    Barbier, Lieven; Abeloos, Johan; De Clercq, Calix; Jacobs, Reinhilde

    2012-08-01

    The aim of this study was to clinically and radiographically evaluate peri-implant bone level changes after rehabilitation of a fully edentulous maxilla by placement of six implants in either fresh extraction sites or healed edentulous ridges up till 18 months after implant placement. Twenty patients with a terminal dentition in the maxillae (11 men, 9 women) received a total of 120 OsseoSpeed implants; 118 implants could be loaded immediately of which 59 were placed in extraction sockets and 59 were placed in healed sites. Within 24 h after surgery, all patients received a chairside-assembled, fibre-reinforced temporary fixed prosthetic reconstruction in occlusion. Six months post-surgery, final screw-retained CoCr (15) or Ti (5) computer numerical control-milled and acrylic-veneered frameworks were placed directly at implant level without interposing abutments. Intraoral radiographs were taken 6 and 18 months after implant placement. Implant survival rate was 100%. Mean marginal bone level was located on average -0.35 mm below the reference point (standard deviation 0.29, range -1.20 to +0.02 mm) 18 months after loading. Whether implants were placed in healed bone sites or fresh extraction sockets did not significantly affect the bone level changes. Furthermore, the use of either CoCr or Ti at the implant level did not significantly affect marginal bone loss. Within the limits of this prospective clinical trial, results seem to indicate that immediate placement and occlusal loading of five to six implants in the edentulous maxilla can be carried out successfully. Whether or not those implants are placed in fresh extraction sockets does not seem to alter the outcome. The present data show a successful 1-year outcome of a treatment protocol involving tooth extraction immediately combined with implant placement and loading. PMID:21932023

  6. Determining the effect of implant surgery on blood oxygen saturation of the adjacent tooth

    PubMed Central

    Kaviani, Nasser; Shahaboyi, Mohammad; Khabazian, Arezoo

    2012-01-01

    Background: Implant surgery requires local anesthesia and drilling. This surgery may affect the blood circulation of the adjacent teeth. In this study, we evaluated the blood oxygen saturation of the healthy adjacent tooth with a pulse oximeter, during implant surgery. Materials and Methods: In this clinical trial study, 15 healthy adult patients, who were candidates for anterior implant surgery and had healthy anterior adjacent teeth, were selected. Blood oxygen saturation of the adjacent tooth and index finger was measured with a pulse oximeter, before and after local anesthetic injection, and also immediately and one hour after completion of surgery. The collected data were analyzed with a Paired Samples Test and Spearman's Correlation Coefficient. (the significance level was at alpha P < 0.05). Results: The mean value of peripheral finger blood Spo2 before local anesthetic injection was 98.2% and remained stable during surgery. In the adjacent tooth, the mean values of the pulpal Spo2, before and after local anesthesia, were 87.73 and 79.27%, respectively; immediately after surgery it was 86.13% and one hour after surgery was 86.4%. The decrease in the value of pulpal Spo2 after local anesthesia compared to before the injection was significant. Also there was an inverse relationship between the numbers of utilized local anesthetic cartridges and the value of pulpal Spo2 after local anesthesia. Conclusion: After giving local anesthesia, the mean value of Spo2 in the adjacent tooth, because of the vasoconstructive effect of epinephrine, was decreased to about 8%. According to this study, the effect of the local anesthetic drug, containing epinephrine, on the blood circulation in the adjacent tooth was significantly more than the trauma from the implant surgery. We wonder if this temporary decrease in blood flow in the adjacent toot is clinically important or not. To answer this question more studies are required. PMID:23162584

  7. Bilateral benign paroxysmal positional vertigo following a tooth implantation.

    PubMed

    Kaplan, Daniel M; Attal, Uriel; Kraus, Mordechai

    2003-04-01

    Benign paroxysmal positional vertigo (BPPV) is a common cause of vertigo and may occur following recent head trauma. Bilateral involvement in BPPV is considered rare and has received little attention in the medical literature. We describe an unusual case of bilateral BPPV in a middle-aged woman that presented during a dental implantation, performed with the use of osteotomes. We discuss the diagnostic and therapeutic challenge of this entity. PMID:12816224

  8. Dental implant as an option for tooth replacement: The awareness of patients at a tertiary hospital in a developing country

    PubMed Central

    Gbadebo, Olaide Shakeerah; Lawal, Folake Barakat; Sulaiman, Amidu Omotayo; Ajayi, Deborah Mojirade

    2014-01-01

    Aim: A survey was set out to evaluate the knowledge of patients about tooth replacement as a whole, and assess their awareness of implant-retained prosthesis as an option of tooth replacement. Materials and Methods: Information on sociodemographic characteristics, knowledge about implant-retained tooth as an option for missing tooth replacement, cost implication, source of information and knowledge about other options of tooth replacement were obtained from patients attending the dental clinics of the University College Hospital, Ibadan, using structured self-administered questionnaires. Data were analyzed using SPSS version 20. Result: A total of 220 patients aged 18-84 years with a mean age of 37.6 (16.5) years participated in the study, with a male to female ratio of 1:1.1. The majority (92.5%) knew that missing teeth can be replaced, while a significantly lower proportion (28.9%) knew about dental implants as an option (P < 0.01). Dentists were the major source of information on dental implants (68%). Only 21 (36.8%) of those who had heard about dental implant had knowledge about the cost (P < 0.000). Conclusion: A low level of awareness about dental implant as tooth replacement option exist in this environment, although most of the study participants were aware that missing teeth can be replaced. PMID:25191063

  9. Use of an implant o-ring attachment for the tooth supported mandibular overdenture: a clinical report.

    PubMed

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

    2011-07-01

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

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

    PubMed Central

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

    2011-01-01

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

  11. The clinical success of tooth- and implant-supported zirconia-based fixed dental prostheses. A systematic review.

    PubMed

    Le, M; Papia, E; Larsson, C

    2015-06-01

    The aim was to make an inventory of the current literature on the clinical performance of tooth- or implant-supported zirconia-based FDPs and analyse and discuss any complications. Electronic databases, PubMed.gov, Cochrane Library and Science Direct, were searched for original studies reporting on the clinical performance of tooth- or implant-supported zirconia-based FDPs. The electronic search was complemented by manual searches of the bibliographies of all retrieved full-text articles and reviews, as well as a hand search of the following journals: International Journal of Prosthodontics, Journal of Oral Rehabilitation, International Journal of Oral & Maxillofacial Implants and Clinical Oral Implants Research. The search yielded 4253 titles. Sixty-eight potentially relevant full-text articles were retrieved. After applying pre-established criteria, 27 studies were included. Twenty-three studies reported on tooth-supported and 4 on implant-supported FDPs. Five of the studies were randomised, comparing Y-TZP-based restorations with metal-ceramic or other all-ceramic restorations. Most tooth-supported FDPs were FDPs of 3-5 units, whereas most implant-supported FDPs were full arch. The majority of the studies reported on 3- to 5-year follow-up. Life table analysis revealed cumulative 5-year survival rates of 93.5% for tooth-supported and 100% for implant-supported FDPs. For tooth-supported FDPs, the most common reasons for failure were veneering material fractures, framework fractures and caries. Cumulative 5-year complication rates were 27.6% and 30.5% for tooth- and implant-supported FDPs, respectively. The most common complications were veneering material fractures for tooth- as well as implant-supported FDPs. Loss of retention occurred more frequently in FDPs luted with zinc phosphate or glass-ionomer cement compared to those luted with resin cements. The results suggest that the 5-year survival rate is excellent for implant-supported zirconia-based FDPs, despite the incidence of complications, and acceptable for tooth-supported zirconia-based FDPs. These results are, however, based on a relatively small number of studies, especially for the implant-supported FDPs. The vast majority of the studies are not controlled clinical trials and have limited follow-up. Thus, interpretation of the results should be made with caution. Well-designed studies with large patient groups and long follow-up times are needed before general recommendations for the use of zirconia-based restorations can be provided. PMID:25580846

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

    PubMed Central

    Quaranta, Alessandro; Poli, Ottavia; Vozza, Iole

    2013-01-01

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

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

    PubMed

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

    2012-01-01

    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 point to determine septum midline. The distances from septum midline to mesial and distal teeth were measured to evaluate the septum midline centralization degree in two different septum heights. The difference between mesial and distal distances represented the septum midline deviation degree. The mesial and distal distances were compared by t-tests, and the septum midline deviation was correlated with septum height using Pearson's correlation test. The mesial and distal distances were not statistically different in the midpoint of the septum height, but they were different at the apical septum height. There was a moderate correlation (r=0.45) between septum midline deviation and septum height. The tooth crown references evaluated on interproximal radiographs determine a high centralization degree of the septum midline on which the insertion site could be defined. The greater centralization degree was observed at the coronal septum area. PMID:21868198

  14. Maxillary anterior esthetic extractions with delayed single-stage implant placement.

    PubMed

    Anson, David

    2002-09-01

    As a result of the high predictability of dental implantology, successful osseointegration is no longer the primary challenge. Rather, esthetics has emerged as the primary challenge. Hard and soft tissue ridge augmentation, performed either in preparation for later implant placement or concurrently with implant placement, has been described in the literature for the esthetic zone. These procedures are still evolving. If, however, ridge collapse can be prevented or minimized after tooth extraction, more predictable outcomes with better esthetics can be accomplished, along with fewer surgical procedures. This article describes a technique for esthetic extraction, as well as delayed esthetic single-stage implant placement, in the maxillary anterior sextant. PMID:12365138

  15. Alveolar ridge preservation of an extraction socket using autogenous tooth bone graft material for implant site development: prospective case series

    PubMed Central

    Yun, Pil-Young; Um, In-Woong; Lee, Hyo-Jung; Yi, Yang-Jin; Bae, Ji-Hyun; Lee, Junho

    2014-01-01

    This case series evaluated the clinical efficacy of autogenous tooth bone graft material (AutoBT) in alveolar ridge preservation of an extraction socket. Thirteen patients who received extraction socket graft using AutoBT followed by delayed implant placements from Nov. 2008 to Aug. 2010 were evaluated. A total of fifteen implants were placed. The primary and secondary stability of the placed implants were an average of 58 ISQ and 77.9 ISQ, respectively. The average amount of crestal bone loss around the implant was 0.05 mm during an average of 22.5 months (from 12 to 34 months) of functional loading. Newly formed tissues were evident from the 3-month specimen. Within the limitations of this case, autogenous tooth bone graft material can be a favorable bone substitute for extraction socket graft due to its good bone remodeling and osteoconductivity. PMID:25551013

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

    PubMed Central

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

    2014-01-01

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

  17. Single atom devices by ion implantation

    NASA Astrophysics Data System (ADS)

    van Donkelaar, Jessica; Yang, C.; Alves, A. D. C.; McCallum, J. C.; Hougaard, C.; Johnson, B. C.; Hudson, F. E.; Dzurak, A. S.; Morello, A.; Spemann, D.; Jamieson, D. N.

    2015-04-01

    To expand the capabilities of semiconductor devices for new functions exploiting the quantum states of single donors or other impurity atoms requires a deterministic fabrication method. Ion implantation is a standard tool of the semiconductor industry and we have developed pathways to deterministic ion implantation to address this challenge. Although ion straggling limits the precision with which atoms can be positioned, for single atom devices it is possible to use post-implantation techniques to locate favourably placed atoms in devices for control and readout. However, large-scale devices will require improved precision. We examine here how the method of ion beam induced charge, already demonstrated for the deterministic ion implantation of 14 keV P donor atoms in silicon, can be used to implant a non-Poisson distribution of ions in silicon. Further, we demonstrate the method can be developed to higher precision by the incorporation of new deterministic ion implantation strategies that employ on-chip detectors with internal charge gain. In a silicon device we show a pulse height spectrum for 14 keV P ion impact that shows an internal gain of 3 that has the potential of allowing deterministic implantation of sub-14 keV P ions with reduced straggling.

  18. Tooth-Colored Fillings

    MedlinePLUS

    ... Procedures Dental Implants Dentures Direct Bonding Implants versus Bridges Orthodontics and Aligners Periodontal Plastic Surgery Porcelain Crowns Porcelain Fixed Bridges Porcelain Veneers Repairing Chipped Teeth Teeth Whitening Tooth- ...

  19. Clinical practice guidelines for recall and maintenance of patients with tooth-borne and implant-borne dental restorations.

    PubMed

    Bidra, Avinash S; Daubert, Diane M; Garcia, Lily T; Kosinski, Timothy F; Nenn, Conrad A; Olsen, John A; Platt, Jeffrey A; Wingrove, Susan S; Chandler, Nancy Deal; Curtis, Donald A

    2016-01-01

    The purpose of this article is to provide guidelines for patient recall regimen, professional maintenance regimen, and at-home maintenance regimen for patients with tooth-borne and implant-borne removable and fixed restorations. The American College of Prosthodontists (ACP) convened a scientific panel of experts appointed by the ACP, American Dental Association, Academy of General Dentistry, and American Dental Hygienists Association, who critically evaluated and debated recently published findings from 2 systematic reviews on this topic. The major outcomes and consequences considered during formulation of the clinical practice guidelines (CPGs) were risk for failure of tooth- and implant-borne restorations. The panel conducted a roundtable discussion of the proposed guidelines, which were debated in detail. Feedback was used to supplement and refine the proposed guidelines, and consensus was attained. A set of CPGs was developed for tooth-borne restorations and implant-borne restorations. Each CPG comprised (1) patient recall, (2) professional maintenance, and (3) at-home maintenance. For tooth-borne restorations, the professional maintenance and at-home maintenance CPGs were subdivided for removable and fixed restorations. For implant-borne restorations, the professional maintenance CPGs were subdivided for removable and fixed restorations and further divided into biological maintenance and mechanical maintenance for each type of restoration. The at-home maintenance CPGs were subdivided for removable and fixed restorations. The clinical practice guidelines presented in this document were initially developed using the 2 systematic reviews. Additional guidelines were developed using expert opinion and consensus, which included discussion of the best clinical practices, clinical feasibility, and risk-benefit ratio to the patient. To the authors' knowledge, these are the first CPGs addressing patient recall regimen, professional maintenance regimen, and at-home maintenance regimen for patients with tooth-borne and implant-borne restorations. This document serves as a baseline with the expectation of future modifications when additional evidence becomes available. PMID:26742161

  20. Single Ion Implantation and Deterministic Doping

    SciTech Connect

    Schenkel, Thomas

    2010-06-11

    The presence of single atoms, e.g. dopant atoms, in sub-100 nm scale electronic devices can affect the device characteristics, such as the threshold voltage of transistors, or the sub-threshold currents. Fluctuations of the number of dopant atoms thus poses a complication for transistor scaling. In a complementary view, new opportunities emerge when novel functionality can be implemented in devices deterministically doped with single atoms. The grand price of the latter might be a large scale quantum computer, where quantum bits (qubits) are encoded e.g. in the spin states of electrons and nuclei of single dopant atoms in silicon, or in color centers in diamond. Both the possible detrimental effects of dopant fluctuations and single atom device ideas motivate the development of reliable single atom doping techniques which are the subject of this chapter. Single atom doping can be approached with top down and bottom up techniques. Top down refers to the placement of dopant atoms into a more or less structured matrix environment, like a transistor in silicon. Bottom up refers to approaches to introduce single dopant atoms during the growth of the host matrix e.g. by directed self-assembly and scanning probe assisted lithography. Bottom up approaches are discussed in Chapter XYZ. Since the late 1960's, ion implantation has been a widely used technique to introduce dopant atoms into silicon and other materials in order to modify their electronic properties. It works particularly well in silicon since the damage to the crystal lattice that is induced by ion implantation can be repaired by thermal annealing. In addition, the introduced dopant atoms can be incorporated with high efficiency into lattice position in the silicon host crystal which makes them electrically active. This is not the case for e.g. diamond, which makes ion implantation doping to engineer the electrical properties of diamond, especially for n-type doping much harder then for silicon. Ion implantation is usually a highly statistical process, where high fluences of energetic ions, ranging from {approx}10{sup 9} to >10{sup 16} cm{sup -2} are implanted. For single atom device development, control over the absolute number of ions is needed and ions have to be placed with high spatial resolution. In the following sections we will discuss a series of approaches to single ion implantation with regard to single ion impact sensing and control of single ion positioning.

  1. Mechanical design, analysis, and laboratory testing of a dental implant with axial flexibility similar to natural tooth with periodontal ligament.

    PubMed

    Pekta?, mer; Tnk, Ergin

    2014-11-01

    At the interface between the jawbone and the roots of natural teeth, a thin, elastic, shock-absorbing tissue, called the periodontal ligament, forms a cushion which provides certain flexibility under mechanical loading. The dental restorations supported by implants, however, involve comparatively rigid connections to the jawbone. This causes overloading of the implant while bearing functional loading together with neighboring natural teeth, which leads to high stresses within the implant system and in the jawbone. A dental implant, with resilient components in the upper structure (abutment) in order to mimic the mechanical behavior of the periodontal ligament in the axial direction, was designed, analyzed in silico, and produced for mechanical testing. The aims of the design were avoiding high levels of stress, loosening of the abutment connection screw, and soft tissue irritations. The finite element analysis of the designed implant revealed that the elastic abutment yielded a similar axial mobility with the natural tooth while keeping stress in the implant at safe levels. The in vitro mechanical testing of the prototype resulted in similar axial mobility predicted by the analysis and as that of a typical natural tooth. The abutment screw did not loosen under repeated loading and there was no static or fatigue failure. PMID:25378380

  2. Considerations for single tooth replacement in an esthetic zonereview of conservative treatment options

    PubMed Central

    Singh, Raghuwar Dayal; Singh, Saumyendra V; Chand, Pooran; Ramashanker

    2012-01-01

    Background This literature review aimed to identify and assess the conservative treatment options for replacing a single missing anterior tooth, for patients who cannot afford implants or traditional bridges. Materials and Methods The evidence was obtained using MEDLINE searches. A total of 19 studies met the inclusion criteria. None of these studies scored higher than 10 of 17, suggesting that all studies did not have strong evidence. Three of the studies examined resin-bonded bridges (RBBs), whereas the other three investigated removable partial dentures (RPDs). None of the studies had random patient selection. Three of these studies had controlled allocation of patients. The other three allowed new patients to enter the study throughout the study period. Placement of the prosthesis was only conducted in one study, whereas the rest of the studies examined patients with preexisting prostheses. Results and Conclusion In general, all 19 studies were weak due to poor study design, no acceptable controls, no direct comparison between RBBs and RPDs, lack of longitudinal studies and no differentiation between the anterior and posterior prostheses. Therefore, no definitive treatment conclusion can be made until studies of stronger design are conducted. PMID:25756015

  3. 3D finite element analysis of immediate loading of single wide versus double implants for replacing mandibular molar

    PubMed Central

    Desai, Shrikar R.; Karthikeyan, I.; Gaddale, Reetika

    2013-01-01

    Purpose: The purpose of this finite element study was to compare the stresses, strains, and displacements of double versus single implant in immediate loading for replacing mandibular molar. Materials and Methods: Two 3D FEM (finite element method) models were made to simulate implant designs. The first model used 5-mm-wide diameter implant to support a single molar crown. The second model used 3.75-3.75 double implant design. Anisotropic properties were assigned to bone model. Each model was analyzed with single force magnitude (100 N) in vertical axis. Results: This FEM study suggested that micromotion can be controlled better for double implants compared to single wide-diameter implants. The Von Mises stress for double implant showed 74.44% stress reduction compared to that of 5-mm implant. The Von Mises elastic strain was reduced by 61% for double implant compared to 5-mm implant. Conclusion: Within the limitations of the study, when the mesiodistal space for artificial tooth is more than 12.5 mm, under immediate loading, the double implant support should be considered. PMID:24554890

  4. Congenitally Missing Maxillary Lateral Incisors: Functional and Periodontal Aspects in Patients Treated with Implants or Space Closure and Tooth Re-Contouring

    PubMed Central

    Marchi, Luciana Manzotti De; Pini, Nbia Inocencya Pavesi; Hayacibara, Roberto Massayuki; Silva, Rafael Santos; Pascotto, Renata Corra

    2012-01-01

    To evaluate functional and periodontal aspects in patients with unilateral or bilateral congenitally missing maxillary lateral incisors, treated with either implants or space closure and tooth re-contouring. The sample consisted of 68 volunteers, divided into 3 groups: SCR - space closure and tooth re-contouring with composite resin (n = 26); SOI implants placed in the area of agenesis (n = 20); and CG - control group (n = 22). A modified Helkimo questionnaire and the Research Diagnostic Criteria for Temporomandibular Disorders were used by a single, previously calibrated evaluator to assess signs and symptoms of temporomandibular joint disorder. The periodontal assessment involved the following aspects: plaque index, bleeding upon probing, pocket depth greater than 3 mm, gingival recession, abfraction, periodontal biotype and papilla index. The data were analyzed using Fisher's exact test and the nonparametric Mann-Whitney and Kruskal-Wallis tests (?=.05). No differences in periodontal status were found between treatments. None of the groups were associated with signs and symptoms of temporomandibular joint disorder. Both treatment alternatives for patients with congenitally missing maxillary lateral incisors were satisfactory and achieved functional and periodontal results similar to those of the control group. PMID:23346262

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

    PubMed Central

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

    2013-01-01

    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. PMID:23710375

  6. Analysis of the effects of different materials in a tooth implant-supported fixed prosthesis using finite element method.

    PubMed

    Dargahi, Javad; Najarian, Siamak; Talebi, Mehdi

    2005-01-01

    In this study, design optimization of a tooth implant-supported fixed prosthesis was investigated theoretically. A three-dimensional finite element analysis was utilized to simulate the stress distribution and deformation, with an emphasis on the material selection for various parts of the prosthesis. This mandibular prosthesis was supported by six implants. The properties of 3 different materials for implants and 4 different materials for framework were incorporated into 12 different models. For the loading conditions used, it was found that the largest displacements occurred at the far ends of the framework and that the resulting deflection was highly dependent on the material properties of the framework. The simulations showed that the stress in the framework was mainly concentrated near the holes in the lower surface and that the highest values of von Mises stresses occurred in the lingual part of the prosthesis. Furthermore, the modeling results revealed that more rigid frameworks led to a corresponding decreased stress in the retaining screws and that high-stress concentration areas moved from the neck of the implant towards the base of it, as the value of Young's modulus increased. It was concluded that the first best model was the Cr-Co alloy for the framework and the Ti alloy for the implant and the second best choice was the Cr-Co alloy for both the framework and the implant. PMID:16010040

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

    PubMed Central

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

    2012-01-01

    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. PMID:22737309

  8. Anterior Sectional Twin Bracket Appliance Innovative Use for Correction of Single Tooth Crossbite: A Case Report with Biomechanics

    PubMed Central

    Raghav, Pradeep; Reddy, Munish C; Kanwal, Ritika

    2015-01-01

    ABSTRACT Anterior sectional twin bracket appliance (ASTBA) is a sectional mechanism that involves two brackets on upper central incisors. This appliance is previously been used for correction of rotated incisors and midline spacing. But, detail biomechanics for single tooth crossbite correction is not previously explained. Here, in this article, we are presenting a detailed biomechanics of ASTBA for anterior single tooth crossbite correction along with case report. How to cite this article: Verma RK, Raghav P, Reddy MC, Kanwal R. Anterior Sectional Twin Bracket Appliance Innovative Use for Correction of Single Tooth Crossbite: A Case Report with Biomechanics. Int J Clin Pediatr Dent 2015;8(1): 66-69. PMID:26124585

  9. Implant-Supported Removable Partial Denture Improves the Quality of Life of Patients with Extreme Tooth Loss.

    PubMed

    Campos, Camila Heitor; Gonalves, Thais Marques Simek Vega; Garcia, Renata Cunha Matheus Rodrigues

    2015-10-01

    This study aimed to evaluate oral health-related quality of life (OHRQoL) in partially dentate subjects, presenting extreme tooth loss in posterior region with missing post-canines, comparing the use of conventional removable partial dentures (RPDs) and implant-supported RPDs. OHRQoL was measured using the Brazilian version of the Oral Health Impact Profile. Twelve subjects presenting maxillary total and mandibular Kennedy Class I edentulism (mean age 62.67.8 years) first received complete maxillary dentures and conventional mandibular free-end RPDs. After two months, the subjects had their OHRQoL assessed. Osseointegrated implants were inserted bilaterally in the mandibular first molar regions, and after four months ball abutments were placed to support the free-end RPD. Two months later, the patients had their OHRQoL reassessed. Wilcoxon signed-rank test was used to evaluate differences in OHRQoL (?=0.05). Results showed improvement in all OHIP-49 domains (p<0.05) after associating implants to the RPD. The mandibular implant-supported free-end RPD significantly improved OHRQoL. PMID:26647929

  10. [Individual cast posts for single anterior implants].

    PubMed

    Bonanini, M; Macaluso, G M; Pizzi, S; Vescovi, P; Gennari, P U

    1990-11-01

    The Authors utilized in order to replace anterior missing teeth osseointegrated implants provided with individual angled posts. These types of abutment are used to allow a good parallel situation between implants with different angulation and also between implants and proximal teeth. The head of this abutment is thread to receive the screw that allows the crown to be fastened. PMID:2097187

  11. Step-by-step full mouth rehabilitation of a nasopharyngeal carcinoma patient with tooth and implant-supported prostheses: A clinical report

    PubMed Central

    Alikhasi, Marzieh; Kazemi, Mahmood; Nokar, Saeed; Khojasteh, Arash; Sheikhzadeh, Sedigheh

    2011-01-01

    This clinical report presents a 46-year-old man diagnosed with nasopharyngeal carcinoma with the chief complaint of masticatory and speech deficiency because of radiation therapy. After a period of controlling post radiation caries, the patient was rehabilitated with tooth and implant supported metal ceramic restorations following surgical and endodontic intervention. PMID:22090777

  12. Ion implantation induced blistering of rutile single crystals

    NASA Astrophysics Data System (ADS)

    Xiang, Bing-Xi; Jiao, Yang; Guan, Jing; Wang, Lei

    2015-07-01

    The rutile single crystals were implanted by 200 keV He+ ions with a series fluence and annealed at different temperatures to investigate the blistering behavior. The Rutherford backscattering spectrometry, optical microscope and X-ray diffraction were employed to characterize the implantation induced lattice damage and blistering. It was found that the blistering on rutile surface region can be realized by He+ ion implantation with appropriate fluence and the following thermal annealing.

  13. A retrospective analysis of episodes of single tooth extraction under general anaesthesia for adults.

    PubMed

    Hong, B; Birnie, A

    2016-01-15

    Objectives To investigate the provision of adult dental extraction under general anaesthesia (DGA) at the Royal Cornwall Hospitals NHS Trust (RCHT) - specifically adult single tooth DGA episodes in regards to numbers, demographics, justifications, and appropriateness regarding the use of resources.Method Data were collected retrospectively from the patient case notes and electronic records for the complete study cohort. This study included all episodes of adult single tooth DGA in all RCHT sites during 2014, except for mandibular third molar and impacted teeth. Each case was tested against the DGA case selection criteria empirically devised for this study.Results In 2014, 106 episodes of adult single tooth DGA were carried out in RCHT that met the inclusion criteria. Younger females from more socio-economically deprived areas of Cornwall were increasingly likely to have this procedure. Mental disorders were the most prevalent co-morbidity (21.7%) in this cohort. The vast majority of patients (93.4%) had previously tolerated dental treatment without the need for general anaesthesia (GA). Many referrals (46.2%) and listings (30.2%) specifically stated patient demand-driven reasons. None of the cohort had DGA due to failure of sedation. There were potentially 11 episodes that met the DGA case selection criteria. Patients waited for 126 days (median) from the referral date for an operation which took seven minutes (median) to complete. The majority (83%) of the cases were simple exodontia. Twenty patients (18.9%) had previous DGA.Conclusion Potentially a considerable proportion of GA prescription appeared to be driven by patient demand rather than clinical need. This study poses a fundamental question - what drives the demand for DGA? National data collection and specific DGA case selection criteria are recommended. PMID:26768464

  14. An in vitro investigation into retention strength and fatigue resistance of various designs of tooth/implant supported overdentures.

    PubMed

    Fatalla, Abdalbseet A; Song, Ke; Du, Tianfeng; Cao, Yingguang

    2012-02-01

    Previously, the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected. Little or no data have been available on the correlation between the attachment system selected and the overdenture support configuration. The purpose of the present study was to evaluate the retention force and fatigue resistance of three attachment systems and four support designs of overdenture prosthesis. Four lower edentulous acrylic models were prepared and eight combinations of attachments groups were investigated in the study. These included: O-Rings with mini-dental implants (MDIs), Dalbo elliptic with Dalbo Rotex and fabricated flexible acrylic attachments with both MDI and Dalbo Rotex. The study was divided into four test groups: groups A and B, controls, and groups C and D, experimental groups. Control group A contained three overdenture supports: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with Dalbo Rotex screwed in. Control group B contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with Dalbo Rotex screwed in at the same MDI position, but on the left side of the model. Experimental group C contained three overdenture support foundations: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with MDI screwed in. Experimental group D contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with MDIs screwed in at the same MDI position, but on the left side of the model. Each group was further divided into two subgroups according to attachment type used. Five samples were prepared for each group. Retention force (N) values were recorded initially (0 cycles) and after 360, 720, 1440 and 2880 insertion and removal cycles. During the tensile test a cross-head speed of 10 mm/min was applied. Values of absolute force (AF) and relative force (RF) were statistically analyzed by two-way ANOVA and multiple comparison Tukey's tests between groups and cycles periods. The results of fatigue tests showed a 50% reduction in retention force in the subgroups with flexible attachments. A triangular design of overdenture support foundations with O-Ring attachments revealed the lowest value of AF and a relatively high reduction in RF. The four overdenture support designs with flexible acrylic attachments improved the retention force and reduced the fatigue retention. Furthermore, the results of the investigation demonstrate that flexible acrylic attachments for both teeth and implant-supported overdentures offer a wide range of retention forces. PMID:22282258

  15. Single-Stage Ear Reconstruction and Hearing Restoration Using Polyethylene Implant and Implantable Hearing Devices.

    PubMed

    Hempel, John Martin

    2015-12-01

    The use of porous polyethylene in reconstructive surgery of the auricle is becoming increasingly accepted. This is a single-stage procedure providing pleasing cosmetic rehabilitation. Further advantages are the possibility of early implantation and the lack of complications caused by harvesting costal cartilage. Additional hearing restoration using middle ear implants allows functional rehabilitation at an early stage. PMID:26667635

  16. Single Visit Apexification Procedure of a Traumatically Injured Tooth with a Novel Bioinductive Material (Biodentine)

    PubMed Central

    Jingarwar, Mahesh Madhukar; Pathak, Anuradha

    2015-01-01

    ABSTRACT Aim of this article is to present a case wherein single visit apexification of a traumatically injured tooth was done with a bioactive materialBiodentine. An injury sustained between the ages of 6 and 14 can adversely affect pulpal health and interrupt root development. In these instances, apexification is generally the preferred treatment. A 10 years old male patient presented with coronal fracture of the left upper central incisor. Clinical and radiographic assessment showed negative pulpal sensibility and arrested apical root development. Artificial apical barrier induction with Biodentine followed by endodontic treatment and prosthetic rehabilitation was decided as the line of treatment. To conclude, this bioactive and biocompatible calcium-based cement can regenerate damaged dental tissues and represents a promising alternative to the conventional multivisit apexification technique. Clinical significance: Biodentine which is a biologically active cement can be an efficient alternative to the conventional apexification materials which were hitherto recommended. How to cite this article: Bajwa NK, Jingarwar MM, Pathak A. Single Visit Apexification Procedure of a Traumatically Injured Tooth with a Novel Bioinductive Material (Biodentine). Int J Clin Pediatr Dent 2015;8(1):58-61. PMID:26124583

  17. Single Glucose Biofuel Cells Implanted in Rats Power Electronic Devices

    PubMed Central

    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

    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

  18. Bonding efficacy of single-step self-etch systems to sound primary and permanent tooth dentin.

    PubMed

    Uekusa, Satoshi; Yamaguchi, Kanako; Miyazaki, Masashi; Tsubota, Keishi; Kurokawa, Hiroyasu; Hosoya, Yumiko

    2006-01-01

    Currently, there is little information regarding the bonding efficacy of single-step self-etch systems to primary tooth dentin. This study examined the microtensile bond strength of single-step self-etch systems (Clearfil tri-S Bond and One-Up Bond F Plus) to sound primary and permanent tooth dentin. Adhesives were applied to flat samples of primary and permanent tooth dentin, and resin composites were bonded according to the manufacturers' instructions. After 24 hours of storage in distilled water at 37 degrees C, hour glass-shaped specimens were produced. They were subjected to microtensile testing at a crosshead speed of 1.0 mm/minute. The results were analyzed using 2-way analysis of variance (ANOVA) followed by the Tukey HSD post-hoc test (alpha=0.05). Field-emission scanning electron microscopy (FE-SEM) observations of the adhesive-treated dentin surfaces and the resin/dentin interface were also conducted. The bond strengths of primary tooth dentin were significantly lower than that of permanent tooth dentin for both self-etch systems: 44.7 +/- 10.4 versus 54.3 +/- 9.0 MPa for Clearfil tri-S Bond and 40.6 +/- 9.9 versus 50.0 +/- 8.7 MPa for One-Up Bond F Plus (p<0.001). There was no statistically significant interaction between the type of adhesive system and the dentin substrate (p=0.957). Although there was no statistically significant difference in the mean values among the different adhesive systems (p=0.094), there was a statistically significant difference in mean values among the different dentin substrates (p<0.001), which were lower for primary tooth dentin than for permanent tooth dentin. The failure modes were also independent of the type of dentin but dependent on the adhesive systems, an equal distribution among the 3 types of failure for Clearfil tri-S Bond and cohesive failures in adhesives for One-Up Bond F Plus. FE-SEM observations of dentin to which adhesive had been applied revealed that the smear layer had been removed and the collagen fibers exposed. Though the bond strengths to primary tooth dentin were lower than to permanent tooth dentin, excellent adaptation of the single-step self-etch systems to both dentin substrates was observed by FE-SEM. Further studies are required to determine the long-term clinical performance of these adhesive systems when applied to primary tooth dentin. PMID:17024945

  19. Tooth position index for the fabrication of a mandibular implant-supported overdenture bar.

    PubMed

    Fridrich, T; Foo, H

    1998-07-01

    This article describes an index for the fabrication of a mandibular implant-supported overdenture bar. The index is a two-piece mold made from an addition silicone putty material. It is used to record and maintain the relative position of the morphologic contours of the trial denture to the master cast. The split-mold design permits direct visualization of the amount of space available for the design of the retentive bar from both the facial and lingual aspects while ensuring room for an adequate thickness of the denture base resin, without the need to remove the teeth from the trial denture wax-up. PMID:9656183

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

    PubMed Central

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

    2013-01-01

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

  1. Evaluation of stress distributions in peri-implant and periodontal bone tissues in 3- and 5-unit tooth and implant-supported fixed zirconia restorations by finite elements analysis

    PubMed Central

    Guven, Sedat; Beydemir, Koksal; Dundar, Serkan; Eratilla, Veysel

    2015-01-01

    Objective: In this study, it is aimed to compare the distribution of stress on periodontal and peri-implant bone tissues in 3- and 5-unit-dental and implant-supported zirconia restorations using finite element analysis. Materials and Methods: Stress distribution formed in periodontal and peri-implant bone tissues as a result of chewing forces was analyzed in dental and implant-supported three-dimensional (3D) finite element models of zirconia restoration with 5-unit placed on the numbers of 43, 44, 45, 46, and 47 and with 3-unit placed on the number of 45, 46, and 47. Four different loading conditions were used. 200 N force was applied in 30 from the buccal inclination of number 43, 45, and 47 restorations separately and totally 850 N force was applied in 30 from the buccal inclination of whole restoration. The study was performed through static nonlinear analysis with the 3D finite element analysis method. Results: Stress accumulation in bone tissues in the tooth-supported model was found less than in implant-supported models. Stress accumulation was observed in the cervical portion of the implant in implant-supported models, and stress accumulation was observed surrounding bone of roots in tooth-supported models. The highest stress values were occurred in 5 unit implant-supported model in all loadings. Conclusion: In posterior restorations increased in the number of supported teeth and implant can reduce the destructive forces on periodontal and peri-implant bone tissues and may allow longer period retention of the restorations in the mouth. PMID:26430359

  2. Single and Multiple Microphone Noise Reduction Strategies in Cochlear Implants

    PubMed Central

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

    2012-01-01

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

  3. Dental Implants

    MedlinePLUS Videos and Cool Tools

    Dental Implants A fuller, more complete smile is within reach. The following information is designed to provide helpful facts so you ... found in nature. What Happens When You Lose a Tooth? When you lose a tooth, especially a ...

  4. The scanning single ion implanter for solid state quantum computer

    NASA Astrophysics Data System (ADS)

    Zhukov, Valery A.

    2004-05-01

    The scanning (step-and-repeat) and projective (simultaneous) methods of ion-optical implantations of single phosphorus 31P ions in hetero-structure Si/SixGe1-x are offered and analyzed with the purpose of formation of qubits of the solid-state quantum computer. Opportunities axial-symmetric electromagnetic objective lenses and existing sources of highly charged ions with reference to the given problem are considered. It is shown, that combined axial-symmetric electromagnetic lenses have advantage in comparison with electrostatic lenses. The combined electromagnetic objective having record small axial aberrations is designed. The optical scheme of scanning single ion implanter with such objective is offered. The critical parameters determining productivity of ion-optical implanter are allocated. They are the allowable lateral discrepancy of localization of implanted ions, a chromatic aberration of an objective, brightness of an ion source and the multiplicity of a charge of doped ions. The formula connecting these values is deduced. Requirements to sources of highly charged ions and the offer on search of new sources of highly charged ions and projective ion-optical schemes of single ion implantation are formulated.

  5. Optima XE Single Wafer High Energy Ion Implanter

    SciTech Connect

    Satoh, Shu; Ferrara, Joseph; Bell, Edward; Patel, Shital; Sieradzki, Manny

    2008-11-03

    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.

  6. Process Performance of Optima XEx Single Wafer High Energy Implanter

    SciTech Connect

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

    2011-01-07

    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.

  7. Single-color centers implanted in diamond nanostructures

    NASA Astrophysics Data System (ADS)

    Hausmann, Birgit J. M.; Babinec, Thomas M.; Choy, Jennifer T.; Hodges, Jonathan S.; Hong, Sungkun; Bulu, Irfan; Yacoby, Amir; Lukin, Mikhail D.; Lon?ar, Marko

    2011-04-01

    The development of material-processing techniques that can be used to generate optical diamond nanostructures containing a single-color center is an important problem in quantum science and technology. In this work, we present the combination of ion implantation and top-down diamond nanofabrication in two scenarios: diamond nanopillars and diamond nanowires. The first device consists of a 'shallow' implant (~20 nm) to generate nitrogen-vacancy (NV) color centers near the top surface of the diamond crystal prior to device fabrication. Individual NV centers are then mechanically isolated by etching a regular array of nanopillars in the diamond surface. Photon anti-bunching measurements indicate that a high yield (>10%) of the devices contain a single NV center. The second device demonstrates 'deep' (~1 ?m) implantation of individual NV centers into diamond nanowires as a post-processing step. The high single-photon flux of the nanowire geometry, combined with the low background fluorescence of the ultrapure diamond, allowed us to observe sustained photon anti-bunching even at high pump powers.

  8. Tooth extraction

    MedlinePLUS

    A tooth extraction is a procedure to remove a tooth from the gum socket. It is usually done by a general ... gum. If you need a more complex tooth extraction: You will be given sedation so you are ...

  9. Impacted tooth

    MedlinePLUS

    ... soothing to the gums. Removal of the tooth (extraction) is the usual treatment for an impacted tooth. ... oral surgeon. Antibiotics may be prescribed before the extraction if the tooth is infected.

  10. Biomaterial Selection for Tooth Regeneration

    PubMed Central

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

    2011-01-01

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

  11. Dose Control System in the Optima XE Single Wafer High Energy Ion Implanter

    SciTech Connect

    Satoh, Shu; Yoon, Jongyoon; David, Jonathan

    2011-01-07

    Photoresist outgassing can significantly compromise accurate dosimetry of high energy implants. High energy implant even at a modest beam current produces high beam powers which create significantly worse outgassing than low and medium energy implants and the outgassing continues throughout the implant due to the low dose in typical high energy implant recipes. In the previous generation of high energy implanters, dose correction by monitoring of process chamber pressure during photoresist outgassing has been used. However, as applications diversify and requirements change, the need arises for a more versatile photoresist correction system to match the versatility of a single wafer high energy ion implanter. We have successfully developed a new dosimetry system for the Optima XE single wafer high energy ion implanter which does not require any form of compensation due to the implant conditions. This paper describes the principles and performance of this new dose system.

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

    PubMed Central

    Moslehifard, Elnaz; Farid, Farzaneh

    2014-01-01

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

  13. Study on Design of Rotor Profile for the Twin Screw Vacuum Pump with Single Thread Tooth

    NASA Astrophysics Data System (ADS)

    Lu, Y.; Guo, B.; Geng, M. F.

    2015-08-01

    The trapezoidal profile is always used as part of tooth profile in the screw vacuum pump. However, interferential phenomenon occurs when using trapezoidal tooth profile. The arc is added to the trapezoidal profile to obtain the self-conjugate curve. The geometric characters of new profiles are compared with the old ones from view point of area of leakage triangle, length of contacting line, area utility coefficient, and etc. The rotor with the selfconjugate curve has characteristics of the small axial leakage area. Radial leakage from the carryover was within the same volume and would not influence the mass flow rate of the vacuum pump. High ultimate vacuum can be reached by utilizing this profile.

  14. Tooth Problems

    MedlinePLUS

    MENU Return to Web version Tooth Problems See complete list of charts. A tooth that causes ongoing pain may be a sign of a serious problem. Use ... you have an injury that knocked out a tooth? Yes You have TOOTH LOSS. DENTAL EMERGENCY See ...

  15. Loading of a single implant in simulated bone.

    PubMed

    Rungsiyakull, Pimduen; Rungsiyakull, Chaiy; Appleyard, Richard; Li, Qing; Swain, Michael; Klineberg, Iven

    2011-01-01

    This study investigated the effect of occlusal design on the strain developed in simulated bone of implant-supported single crown models. Triaxial strain gauges were attached at the cervical area of each model. Occlusal design, load location, and magnitude were examined to determine the maximum axial principal strains (?) of four occlusal designs: 30-degree cusp inclination with 4- and 6-mm occlusal table dimensions and a 10-degree cusp inclination with 4- and 6-mm occlusal table dimensions. Statistical differences were found for peak average maximum principal strains between each occlusal design when the applied load was directed along the central fossa and 2 mm buccal to the central fossa along the inclined plane, with strain gauges attached at the cervicobuccal (P < .001) and cervicolingual (P ? .001) aspects. In all loading conditions, the 30-degree cusp inclination and 6-mm occlusal table dimension consistently presented the largest strains compared with the other occlusal designs. A reduced cusp inclination and occlusal table dimension effectively reduced experimental bone strain on implant-supported single crowns. The occlusal table dimension appeared to have a relatively more important role than cusp inclination. PMID:21479281

  16. 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

    Schmeide, Matthias; Kontratenko, Serguei; Krimbacher, Bernhard; Mueller, Ralf Peter

    2008-11-03

    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.

  17. Optimized single pulse stimulation strategy for retinal implants

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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.

  18. Tooth Disorders

    MedlinePLUS

    ... made of a hard, bonelike material. Inside the tooth are nerves and blood vessels. You need your ... These include eating, speaking and even smiling. But tooth disorders are nothing to smile about. They include ...

  19. Development of patient-based questionnaire about aesthetic and functional differences between overdentures implant-supported and overdentures tooth-supported. Study of 43 patients with a follow up of 1 year

    PubMed Central

    GARGARI, M.; PRETE, V.; PUJIA, M.; CERUSO, F. M.

    2013-01-01

    SUMMARY Development of patient-based questionnaire about aesthetic and functional differences between overdentures implant-supported and overdentures tooth-supported. Study of 43 patients with a follow up of 1 year. Objective The aim of this study is to compare functional efficiency and patients satisfaction between tooth-supported and implant-supported overdenture through a questionnaire that accurately reflects the real concerns of patients with dental prosthesis. Methods Forty-three patients were selected from the out patient clinic, Department of Dentistry Fra G.B. Orsenigo Ospedale San Pietro F.B.F., Rome, Italy. Their age were ranging from 61 to 83 years. Eighteen patients were rehabilitated with overdentures supported by natural teeth and twenty-five with overdentures implant-supported. Discussion and Result The questionnaire proposed one year after the insertion of the prosthetis has showed that there isnt difference statistically significant in terms of function, phonetics and aesthetics between overdenture implant-supported and tooth-supported. Conclusions The results of the questionnaire showed that the patients generally had a high level of satisfaction concern to the masticatory function, esthetics and phonetics. In addition, on average, they havent difficulty in removal and insertion of the denture and in oral hygiene. They havent in both groups problems related to fractures. PMID:23741602

  20. Fractures related to occlusal overload with single posterior implants: a clinical report.

    PubMed

    Conrad, Heather J; Schulte, John K; Vallee, Mark C

    2008-04-01

    This clinical report describes 2 patient situations in which fractures related to occlusal overload occurred with a single posterior implants. The initial clinical presentation of both patients appeared to be screw loosening, but upon further examination, implant and abutment fractures were identified. Several factors are described that have been implicated in the etiology of implant fractures, including occlusal overload, implant location, inadequate fit of the prosthesis, design of the prosthesis, progressive bone loss, metal fatigue, implant diameter, manufacturing defects, and galvanic activity. This article describes the management of implant and abutment fractures and discusses possible mechanisms of failure for the patient situations presented. Careful treatment planning and execution of implant therapy is necessary to minimize the risk of implant and component fractures. PMID:18395533

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

    SciTech Connect

    Sano, Makoto; Yamada, Tatsuya; Sato, Fumiaki; Tsukihara, Mitsukuni; Sugitani, Michiro

    2008-11-03

    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.

  2. Tooth anatomy

    MedlinePLUS

    The part of the tooth you can see is called the crown. The outer surface of the crown is made of enamel. Just beneath the ... The gum surrounds the base (root) of the tooth. The root of the tooth extends down into ...

  3. Stress Distribution Around Single Short Dental Implants: A Finite Element Study.

    PubMed

    Vidya Bhat, S; Premkumar, Priyanka; Kamalakanth Shenoy, K

    2014-12-01

    Bone height restrictions are more common in the posterior regions of the mandible, because of either bone resorption resulting from tooth loss or even anatomic limitations, such as the position of the inferior alveolar nerve. In situations where adequate bone height is not available in the posterior mandible region, smaller lengths of implants may have to be used but it has been reported that the use of long implants (length ?10 mm) is a positive factor in osseointegration and authors have reported failures with short implants. Hence knowledge about the stress generated on the bone with different lengths of implants needs scientific evaluation. The purpose of this study was to compare and evaluate the influence of different lengths of implants on stress upon bone in mandibular posterior area. A 3 D finite element model was made of the posterior mandible using the details from a CT scan, using computer software (ANSYS 12). Four simulated implants with lengths 6 mm, 8 mm, 10 mm and 13 mm were placed in the centre of the bone. A static vertical force of 250 N and a static horizontal force of 100 N were applied. The stress generated in the cortical and cancellous bone around the implant were recorded and evaluated with the help of ANSYS. In this study, Von Mises stress on a 6 mm implant under a static vertical load of 250 N appeared to be almost in the same range of 8 and 10 mm implant which were more as compared to 13 mm implant. Von Mises stress on a 6mm implant under a static horizontal load of 100N appeared to be less when compared to 8, 10 and 13 mm implants. From the results obtained it may be inferred that under static horizontal loading conditions, shorter implants receive lesser load and thus may tend to transfer more stresses to the surrounding bone. While under static vertical loading the shorter implants bear more loads and comparatively transmit lesser load to the surrounding bone. PMID:26199508

  4. Single ion implantation for single donor devices using Geiger mode detectors

    NASA Astrophysics Data System (ADS)

    Bielejec, E.; Seamons, J. A.; Carroll, M. S.

    2010-02-01

    Electronic devices that are designed to use the properties of single atoms such as donors or defects have become a reality with recent demonstrations of donor spectroscopy, single photon emission sources, and magnetic imaging using defect centers in diamond. Ion implantation, an industry standard for atom placement in materials, requires augmentation for single ion capability including a method for detecting a single ion arrival. Integrating single ion detection techniques with the single donor device construction region allows single ion arrival to be assured. Improving detector sensitivity is linked to improving control over the straggle of the ion as well as providing more flexibility in lay-out integration with the active region of the single donor device construction zone by allowing ion sensing at potentially greater distances. Using a remotely located passively gated single ion Geiger mode avalanche diode (SIGMA) detector we have demonstrated 100% detection efficiency at a distance of >75 µm from the center of the collecting junction. This detection efficiency is achieved with sensitivity to ~600 or fewer electron-hole pairs produced by the implanted ion. Ion detectors with this sensitivity and integrated with a thin dielectric, for example a 5 nm gate oxide, using low energy Sb implantation would have an end of range straggle of <2.5 nm. Significant reduction in false count probability is, furthermore, achieved by modifying the ion beam set-up to allow for cryogenic operation of the SIGMA detector. Using a detection window of 230 ns at 1 Hz, the probability of a false count was measured as ~10-1 and 10-4 for operation temperatures of ~300 K and ~77 K, respectively. Low temperature operation and reduced false, 'dark', counts are critical to achieving high confidence in single ion arrival. For the device performance in this work, the confidence is calculated as a probability of >98% for counting one and only one ion for a false count probability of 10-4 at an average ion number per gated window of 0.015.

  5. Single ion implantation for single donor devices using Geiger mode detectors.

    PubMed

    Bielejec, E; Seamons, J A; Carroll, M S

    2010-02-26

    Electronic devices that are designed to use the properties of single atoms such as donors or defects have become a reality with recent demonstrations of donor spectroscopy, single photon emission sources, and magnetic imaging using defect centers in diamond. Ion implantation, an industry standard for atom placement in materials, requires augmentation for single ion capability including a method for detecting a single ion arrival. Integrating single ion detection techniques with the single donor device construction region allows single ion arrival to be assured. Improving detector sensitivity is linked to improving control over the straggle of the ion as well as providing more flexibility in lay-out integration with the active region of the single donor device construction zone by allowing ion sensing at potentially greater distances. Using a remotely located passively gated single ion Geiger mode avalanche diode (SIGMA) detector we have demonstrated 100% detection efficiency at a distance of >75 microm from the center of the collecting junction. This detection efficiency is achieved with sensitivity to approximately 600 or fewer electron-hole pairs produced by the implanted ion. Ion detectors with this sensitivity and integrated with a thin dielectric, for example a 5 nm gate oxide, using low energy Sb implantation would have an end of range straggle of <2.5 nm. Significant reduction in false count probability is, furthermore, achieved by modifying the ion beam set-up to allow for cryogenic operation of the SIGMA detector. Using a detection window of 230 ns at 1 Hz, the probability of a false count was measured as approximately 10(-1) and 10(-4) for operation temperatures of approximately 300 K and approximately 77 K, respectively. Low temperature operation and reduced false, 'dark', counts are critical to achieving high confidence in single ion arrival. For the device performance in this work, the confidence is calculated as a probability of >98% for counting one and only one ion for a false count probability of 10(-4) at an average ion number per gated window of 0.015. PMID:20101077

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

    PubMed

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

    2012-10-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2005-02-01

    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 "top down" strategy for the construction of prototype solid state quantum computer devices based on phosphorus donors in silicon. We have developed a method of single ion implantation and online registration that employs detector electrodes adjacent to the area into which the donors are to be implanted. The implantation sites are positioned with nanometer accuracy using an electron beam lithography patterned PMMA mask. Control of the implantation depth of 20 nm is achieved by tuning the phosphorus ion energy to 14 keV. The counting of single ion implantation in each site is achieved by the detection of e-/h+ pairs produced by the implanted phosphorus ion in the substrate. The system is calibrated by use of Mn K-line x-rays (5.9 and 6.4 keV) and we find the ionization energy of the 14 keV phosphorus ions in silicon to be about 3.5-4.0 keV for implants through a 5 nm SiO2 surface layer. This paper describes the development of an improved PIN detector structure that provides more reliable performance of the earlier MOS structure. With the new structure, the energy noise threshold has been minimized to 1 keV or less. Unambiguous detection/counting of single keV ion implantation events were achieved with a confidence level greater than 98% with a reliable and reproducible fabrication process.

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

    PubMed Central

    Khetarpal, Ambica; Talwar, Sangeeta; Verma, Mahesh

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2005-02-01

    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 atoms are positioned ~50 nm apart, to form a qubit test device. A series of process steps has been developed to repair implant damage, define surface control gates, and to define single electron transistors used for qubit readout via the detection of sub-electron charge transfer signals. Preliminary electrical measurements on these devices show single charge transfer events that are resilient to thermal cycling.

  10. Percutaneous pulmonary valve implantation in a single artery branch: A preliminary experience

    PubMed Central

    Chessa, Massimo; Butera, Gianfranco; Giugno, Luca; Micheletti, Angelo; Negura, Diana G; Carminati, Mario

    2015-01-01

    To describe preliminary experience of percutaneous pulmonary valve implantation, in a single pulmonary branch position. Two procedures in 2 patients from a single center are described, where implantation of percutaneous valves within a single pulmonary artery branch was technically successful. The procedural indication was pulmonary valve regurgitation and/or residual stenosis. The 2 patients were symptomatic. An Edwards Sapien™ valve (Patient 1), and a Medtronic Melody™ valve (Patient 2) were implanted. Both pts were discharged with an excellent valve function. In this report it is underlined that this modality is technically feasible and may be considered an option in patients with congenital heart defect under special circumstances. PMID:26516424

  11. Does crown/implant ratio influence the survival and marginal bone level of short single implants in the mandibular molar? A preliminary investigation consisting of 12 patients.

    PubMed

    Ghariani, L; Segaan, L; Rayyan, M M; Galli, S; Jimbo, R; Ibrahim, A

    2016-02-01

    Crown/implant (C/I) ratio has been proven to not affect the survival of the implants; however, it is also a fact that no evidence exists with regard to the use of single short implants in the mandibular molar. The aim of this study was to determine whether the crown/implant ratios of single implant-supported fixed restorations on implants of 6-8mm in the mandibular molar have an impact on the implant survival and marginal bone maintenance. Twelve short dental implants (6-8mm) were installed and restored with single crowns, loaded after 3months of healing. The restorations were divided according to crown-to-implant ratio into two groups: Group 1: C/I<20 and Group 2: C/I?20. Alveolar bone loss was measured using CBCT scan, taken at the implant placement and after 12months follow-up from loading. Reduced implant/crown ratio shown no statistic significant differences on implant survival and the alveolar bone level compared with recommended implant/crown ratio. Within the limitation of this study, it can be concluded that reduced C/I ratio could be used as a substitute for recommended C/I ratio in severely mandibular atrophic residual alveolar ridges. PMID:26333185

  12. Single molar replacement with a progressive thread design implant system: a retrospective clinical report.

    PubMed

    Romanos, G E; Nentwig, G H

    2000-01-01

    Many clinical studies have shown that replacement of molars with only 1 implant is commonly associated with various functional complications, such as implant fracture and screw loosening. Thus, multiple implants have been recommended to withstand the high occlusal forces present in the molar region. The aim of this retrospective study was to evaluate the clinical response to the use of single implants with a progressive thread design (Ankylos) in the replacement of molar teeth. Fifty-eight implants (10 in the maxilla and 48 in the mandible) were placed in 51 patients. The implants were in situ for 29.30 +/- 16.52 months and in function for 20.60 +/- 16.64 months. All crowns were cemented to the abutments. The crown occlusion was adjusted to obtain minimal normal contacts in the centric occlusion and eccentric positions. Implants were clinically and radiographically evaluated, and clinical indices (Plaque Index, Sulcus Bleeding Index, probing pocket depth, keratinized mucosa width, Perio-test) were recorded immediately before the placement of the prosthesis and once annually. Vertical and horizontal bone loss were also examined radiographically. Two implants were lost (1 because of fracture in a patient who was a bruxer and another because of abutment fracture in the endosseous part of the implant). All clinical and radiographic parameters of most of the implants were comparable to the values found for the same type of implant in other clinical indications. The reduced incidence of failure (96.55% survival rate) found in this study with the Ankylos implant system compared to the results reported in the literature indicate that this system can be used for the replacement of molars using single-implant-supported restorations. PMID:11151582

  13. Implantation of a modified Freestyle valve with a single inflow suture line: technical patterns and advantages.

    PubMed

    Grandmougin, Daniel; Fayad, Georges

    2006-09-01

    Subcoronary implantation of stentless valves may be a surgical challenge in the small aortic root. In addition, calcifications of coronary ostia may interfere with the procedure. We present a technique to trim a Freestyle stentlesss root (Medtronic Inc, Minneapolis, MN) and facilitate implantation with a single inflow suture line. PMID:16928565

  14. Interaural stimulation timing in single sided deaf cochlear implant users.

    PubMed

    Zirn, S; Arndt, S; Aschendorff, A; Wesarg, T

    2015-10-01

    The interaural time difference (ITD) is an important cue for the localization of sounds. ITD changes as little as 10?s can be detected by the human auditory system. By provision of one ear with a cochlear implant (CI) ITD are altered due to the partial replacement of the peripheral auditory system. A hearing aid (HA), in contrast, does not replace but adds a processing delay component to the peripheral auditory system extending ITD. The aim of the present study was to quantify interaural stimulation timing between these different modalities to estimate the need for central auditory temporal compensation in single sided deaf CI users or bimodal CI/HA users. For this purpose, wave V latencies of auditory brainstem responses evoked either acoustically (ABR) or electrically via the CI (EABR) have been measured. The sum of delays consisting of CI signal processing measured in the MED-EL OPUS2 audio processor and EABR wave V latencies evoked on different intracochlear sites allowed an estimation of the entire CI channel-specific delay for MED-EL MAESTRO CI systems. We compared these values with ABR wave V latencies measured in the contralateral normal hearing or HA provided ear in different frequency bands. The results showed that EABR wave V latencies were consistently shorter than those evoked acoustically in the unaided normal hearing ear. Thus, artificial delays within the audio processor can be implemented to adjust interaural stimulation timing. The currently implemented group delays in the MED-EL CI system turned out to be reasonably similar to those of the unaided ear. For adjustment of CI and contralateral HA, in contrast, an adjustable additional across-frequency delay in the range of 1-11ms implemented in the CI would be required. Especially for bimodal CI/HA users the adjustment of interaural stimulation timing may induce improved binaural hearing, reduced need for central auditory temporal compensation and increased acceptance of the CI/HA provision. PMID:26302945

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

    SciTech Connect

    Schmeide, Matthias; Bukethal, Christoph

    2008-11-03

    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.

  16. In Vitro Assessment of Single-Retainer Tooth-Colored Adhesively Fixed Partial Dentures for Posterior Teeth

    PubMed Central

    Bortolotto, Tissiana; Monaco, Carlo; Onisor, Ioana; Krejci, Ivo

    2010-01-01

    The purpose of this paper was to investigate, by means of marginal adaptation and fracture strength, three different types of single retainer posterior fixed partial dentures (FPDs) for the replacement of a missing premolar. Two-unit cantilever FPDs were fabricated from composite resin, feldspathic porcelain, and fiber-reinforced composite resin. After luting procedures and margin polishing, all specimens were subjected to a Scanning Electron Microscopic marginal evaluation both prior to and after thermomechanical loading with a custom made chewing simulator comprising both thermal and mechanical loads. The results indicated that the highest score of marginal adaptation, that is, the closest score to 100% of continuous margins, at the tooth-composite resin interface was attained by the feldspathic porcelain group (88.1% median), followed by the fiber-reinforced composite resin group (78.9% median). The worse results were observed in the composite resin group (58.05% median). Fracture strength was higher in feldspathic porcelain (196N median) when compared to resin composite (114.9 N median). All the fixed prostheses made of fiber-reinforced composite resin detached from the abutment teeth before fracturing, suggesting that the adhesive surface's retainer should be increased. PMID:20652071

  17. In situ optimization of co-implantation and substrate temperature conditions for Nv-center formation in single crystal diamonds

    SciTech Connect

    Schwartz, Julian; Michaelides, Philip; Weis, Christoph D.; Schenkel, Thomas

    2011-02-01

    We present first results from in situ characterization of NV-formation in single crystal diamonds following implantation of low energy nitrogen ions (7.7 keV), co-implantation of hydrogen, helium and carbon ions and in situ annealing. Diamond samples were implanted at room temperature or at a temperature of 780{degree} C during the implantation steps. We find that dynamic annealing during co-implantation enhances NV-center formation by up to 25%.

  18. Single Word and Sentence Intelligibility in Children with Cochlear Implants

    ERIC Educational Resources Information Center

    Khwaileh, Fadwa A.; Flipsen, Peter, Jr.

    2010-01-01

    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). Naive listeners responded by writing sentences heard or with two types of responses

  19. Evaluation of single implants placed in the posterior mandibular area under immediate loading: a prospective study.

    PubMed

    Guidetti, L G C; Monnazzi, M S; Piveta, A C G; Gabrielli, M A C; Gabrielli, M F R; Pereira Filho, V A

    2015-11-01

    The aim of this study was to evaluate the survival of single dental implants subjected to immediate function. Twelve patients with edentulous areas in the posterior mandible were included in the study. All received at least one regular platform dental implant (3.75mm11mm or 3.75mm13mm). Clinical and radiographic parameters were evaluated. The survival rate after 12 months was 83.3%. The implants showed no clinical mobility, had implant stability quotient values (ISQ; Osstell) around 70, bone loss of up to 2mm, and a probing depth of ?3mm. Although the posterior mandible is an area in which the immediate loading of dental implants should be performed with caution, this treatment presented a good success rate in the present study sample. PMID:26194771

  20. 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 ...

  1. The local structure and ferromagnetism in Fe-implanted SrTiO₃ single crystals

    SciTech Connect

    Lobacheva, O. Chavarha, M.; Yiu, Y. M.; Sham, T. K.; Goncharova, L. V.

    2014-07-07

    We report a connection between the local structure of low-level Fe impurities and vacancies as the cause of ferromagnetic behavior observed in strontium titanate single crystals (STO), which were implanted with Fe and Si ions at different doses then annealed in oxygen. The effects of Fe doping and post-implantation annealing of STO were studied by X-ray Absorption Near Edge Structure (XANES) spectroscopy and Superconducting Quantum Interference Device magnetometry. XANES spectra for Fe and Ti K- and L-edge reveal the changes in the local environment of Fe and Ti following the implantation and annealing steps. The annealing in oxygen atmosphere partially healed implantation damages and changed the oxidation state of the implanted iron from metallic Fe⁰ to Fe²⁺/Fe³⁺ oxide. The STO single crystals were weak ferromagnets prior to implantation. The maximum saturation moment was obtained after our highest implantation dose of 2×10¹⁶ Fe atom/cm², which could be correlated with the metallic Fe⁰ phases in addition to the presence of O/Ti vacancies. After recrystallization annealing, the ferromagnetic response disappears. Iron oxide phases with Fe²⁺ and Fe³⁺ corresponding to this regime were identified and confirmed by calculations using Real Space Multiple Scattering program (FEFF9).

  2. Comparison of migration behavior between single and dual lag screw implants for intertrochanteric fracture fixation

    PubMed Central

    Kouvidis, George K; Sommers, Mark B; Giannoudis, Peter V; Katonis, Pavlos G; Bottlang, Michael

    2009-01-01

    Background Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evaluated in surrogate specimens using an established laboratory model of hip screw cut-out failure. Methods Five dual lag screw implants (Endovis, Citieffe) and five single lag screw implants (DHS, Synthes) were tested in the Hip Implant Performance Simulator (HIPS) of the Legacy Biomechanics Laboratory. This model simulated osteoporotic bone, an unstable fracture, and biaxial rocking motion representative of hip loading during normal gait. All constructs were loaded up to 20,000 cycles of 1.45 kN peak magnitude under biaxial rocking motion. The migration kinematics was continuously monitored with 6-degrees of freedom motion tracking system and the number of cycles to implant cut-out was recorded. Results The dual lag screw implant exhibited significantly less migration and sustained more loading cycles in comparison to the DHS single lag screw. All DHS constructs failed before 20,000 cycles, on average at 6,638 ± 2,837 cycles either by cut-out or permanent screw bending. At failure, DHS constructs exhibited 10.8 ± 2.3° varus collapse and 15.5 ± 9.5° rotation around the lag screw axis. Four out of five dual screws constructs sustained 20,000 loading cycles. One dual screw specimens sustained cut-out by medial migration of the distal screw after 10,054 cycles. At test end, varus collapse and neck rotation in dual screws implants advanced to 3.7 ± 1.7° and 1.6 ± 1.0°, respectively. Conclusion The single and double lag screw implants demonstrated a significantly different migration resistance in surrogate specimens under gait loading simulation with the HIPS model. In this model, the double screw construct provided significantly greater resistance against varus collapse and neck rotation in comparison to a standard DHS lag screw implant. PMID:19450283

  3. Impact of crestal and subcrestal implant placement in peri-implant bone: A prospective comparative study

    PubMed Central

    Pellicer-Chover, Hilario; Peñarrocha-Diago, María; Peñarrocha-Oltra, David; Gomar-Vercher, Sonia; Agustín-Panadero, Rubén

    2016-01-01

    Background To assess the influence of the crestal or subcrestal placement of implants upon peri-implant bone loss over 12 months of follow-up. Material and Methods Twenty-six patients with a single hopeless tooth were recruited in the Oral Surgery Unit (Valencia University, Valencia, Spain). The patients were randomized into two treatment groups: group A (implants placed at crestal level) or group B (implants placed at subcrestal level). Control visits were conducted by a trained clinician at the time of implant placement and 12 months after loading. A previously established standard protocol was used to compile general data on all patients (sex and age, implant length and diameter, and brushing frequency). Implant success rate, peri-implant bone loss and the treatment of the exposed implant surface were studied. The level of statistical significance was defined as 5% (α=0.05). Results Twenty-three patients (8 males and 15 females, mean age 49.8±11.6 years, range 28-75 years) were included in the final data analyses, while three were excluded. All the included subjects were nonsmokers with a brushing frequency of up to twice a day in 85.7% of the cases. The 23 implants comprised 10 crestal implants and 13 subcrestal implants. After implant placement, the mean bone position with respect to the implant platform in group A was 0.0 mm versus 2.16±0.88 mm in group B. After 12 months of follow-up, the mean bone positions were -0.06±1.11 mm and 0.95±1.50 mm, respectively - this representing a bone loss of 0.06±1.11 mm in the case of the crestal implants and of 1.22±1.06 mm in the case of the subcrestal implants (p=0.014). Four crestal implants and 5 subcrestal implants presented peri-implant bone levels below the platform, leaving a mean exposed treated surface of 1.13 mm and 0.57 mm, respectively. The implant osseointegration success rate at 12 months was 100% in both groups. Conclusions Within the limitations of this study, bone loss was found to be greater in the case of the subcrestal implants, though from the clinical perspective these implants presented bone levels above the implant platform after 12 months of follow-up. Key words:Immediate implants, tooth extraction, dental implants, single-tooth, crestal bone, placement level. PMID:26615504

  4. Tooth - abnormal shape

    MedlinePLUS

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  5. Cochlear Implantation and Single-sided Deafness: A Systematic Review of the Literature

    PubMed Central

    Cabral Junior, Francisco; Pinna, Mariana Hausen; Alves, Ricardo Dourado; Malerbi, Andrea Felice dos Santos; Bento, Ricardo Ferreira

    2015-01-01

    Introduction?Current data show that binaural hearing is superior to unilateral hearing, specifically in the understanding of speech in noisy environments. Furthermore, unilateral hearing reduce ons ability to localize sound. Objectives?This study provides a systematic review of recent studies to evaluate the outcomes of cochlear implantation in patients with single-sided deafness (SSD) with regards to speech discrimination, sound localization and tinnitus suppression. Data Synthesis?We performed a search in the PubMed, Cochrane Library and Lilacs databases to assess studies related to cochlear implantation in patients with unilateral deafness. After critical appraisal, eleven studies were selected for data extraction and analysis of demographic, study design and outcome data. Conclusion?Although some studies have shown encouraging results on cochlear implantation and SSD, all fail to provide a high level of evidence. Larger studies are necessary to define the tangible benefits of cochlear implantation in patients with SSD. PMID:26722349

  6. Cochlear Implantation and Single-sided Deafness: A Systematic Review of the Literature.

    PubMed

    Cabral Junior, Francisco; Pinna, Mariana Hausen; Alves, Ricardo Dourado; Malerbi, Andrea Felice Dos Santos; Bento, Ricardo Ferreira

    2016-01-01

    Introduction?Current data show that binaural hearing is superior to unilateral hearing, specifically in the understanding of speech in noisy environments. Furthermore, unilateral hearing reduce ons ability to localize sound. Objectives?This study provides a systematic review of recent studies to evaluate the outcomes of cochlear implantation in patients with single-sided deafness (SSD) with regards to speech discrimination, sound localization and tinnitus suppression. Data Synthesis?We performed a search in the PubMed, Cochrane Library and Lilacs databases to assess studies related to cochlear implantation in patients with unilateral deafness. After critical appraisal, eleven studies were selected for data extraction and analysis of demographic, study design and outcome data. Conclusion?Although some studies have shown encouraging results on cochlear implantation and SSD, all fail to provide a high level of evidence. Larger studies are necessary to define the tangible benefits of cochlear implantation in patients with SSD. PMID:26722349

  7. Mechanism of apatite formation on hydrogen plasma-implanted single-crystal silicon

    NASA Astrophysics Data System (ADS)

    Liu, Xuanyong; Fu, Ricky K. Y.; Chu, Paul K.; Ding, Chuanxian

    2004-10-01

    Hydrogen is implanted into single-crystal silicon wafers using plasma ion immersion implantation to improve the surface bioactivity and the mechanism of apatite formation is investigated. Our micro-Raman and transmission electron microscopy results reveal the presence of a disordered silicon surface containing Si-H bonds after hydrogen implantation. When the sample is immersed in a simulated body fluid, the Si-H bonds on the silicon wafer initially react with water to produce a negatively charged surface containing the functional group (?Si-O-) that subsequently induces the formation of apatite. A good understanding of the formation mechanism of apatite on hydrogen implanted silicon is not only important from the viewpoint of biophysics but also vital to the actual use of silicon-based microchips and MEMS inside a human body.

  8. Mechanism for diamond nucleation and growth on single crystal copper surfaces implanted with carbon

    NASA Technical Reports Server (NTRS)

    Ong, T. P.; Xiong, Fulin; Chang, R. P. H.; White, C. W.

    1992-01-01

    The nucleation and growth of diamond crystals on single-crystal copper surfaces implanted with carbon ions is studied. Microwave plasma-enhanced chemical-vapor deposition is used for diamond growth. The single-crystal copper substrates were implanted either at room or elevated temperature with carbon ions prior to diamond nucleation. This procedure leads to the formation of a graphite film on the copper surface which greatly enhances diamond crystallite nucleation. A simple lattice model is constructed for diamond growth on graphite as 111 line (diamond) parallel to 0001 line (graphite) and 110 line (diamond) parallel to 1 1 -2 0 (graphite).

  9. Tooth - abnormal colors

    MedlinePLUS

    ... things can cause tooth discoloration. The change in color may affect the entire tooth, or appear as spots or ... the tooth enamel. Your genes affect your tooth color. Other things ... include: Congenital diseases Environmental factors Infections ...

  10. Nanofabrication processes for single-ion implantation of silicon quantum computer devices

    NASA Astrophysics Data System (ADS)

    McKinnon, Rita P.; Stanley, Fay E.; Lumpkin, Nancy E.; Gauja, Eric; Macks, Linda D.; Mitic, Mladen; Chan, Victor; Peceros, Katia; Buehler, Tilo M.; Dzurak, Andrew S.; Clark, Robert G.; Yang, Changyi; Jamieson, David N.; Prawer, Steven D.

    2002-10-01

    We describe progress in nanofabrication processes for the production of silicon-based quantum computer devices. The processes are based on single-ion implantation to place phosphorus-31 atoms in accurate locations, precisely self-aligned to metal control gates. These fabrication schemes involve multi-layer resist and metal structures, electron beam lithography and multi-angled aluminium shadow evaporation. The key feature of all fabrication schemes is an integrated combination of patterns in different resist and metal layers that together define self-aligning metal gate structures as well as channels down to the substrate through which to implant the phosphorus. Central to this process is a new technique that allows for control and detection of the implantation process at a single-ion level.

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

    SciTech Connect

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

    2008-11-03

    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.

  12. Digital subtraction radiography evaluation of longitudinal bone density changes around immediate loading implants: a pilot study

    PubMed Central

    Carneiro, LS; da Cunha, HA; Leles, CR; Mendona, EF

    2012-01-01

    Objective The aim of this study was to assess longitudinal quantitative changes in bone density around different implant loading protocols and implant surfaces measured by digital subtraction radiography (DSR). Methods 12 patients received bilateral homologous standard and TiUnite (Nobel Biocare, Kloten, Switzerland) single-tooth implants under 2 implantloading protocols: immediate loading (8 patients, 16 implants, 12 maxillary) and conventional loading (4 patients, 8 implants, 4 maxillary). Standardized periapical radiographs were taken immediately after implant placement (baseline image) and at the 3-month, 6-month and 12-month follow ups. Radiographic images were digitized and submitted to digital subtraction using the DSR system (Electro Medical System, Nyon, Switzerland), resulting in three subtracted images. Quantitative analysis of bone density was performed using Image Tool software (University of Texas Health Science Centre, San Antonio, TX) to assess pixel value changes in five areas around the implants (crestal, subcrestal, medial third, apicallateral and apical). Results Repeated-measures analysis of variance showed that grey levels were significantly influenced by follow-up time and implant-loading protocol. A linear increase in grey levels was found for immediate loading (IML) implants and a significant decrease in grey levels was observed in the 12-month follow up for conventional loading implants. No effect of implant surface treatment was observed. Conclusion In conclusion, IML protocol induced mineral bone gain around single-tooth implants after the first year under function for cases with favourable bone conditions. PMID:22074866

  13. Controlled shallow single-ion implantation in silicon using an active substrate for sub-20-keV ions

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

    We demonstrate a method for the controlled implantation of single ions into a silicon substrate with energy of sub-20-keV. The method is based on the collection of electron-hole pairs generated in the substrate by the impact of a single ion. We have used the method to implant single 14-keV P31 ions through nanoscale masks into silicon as a route to the fabrication of devices based on single donors in silicon.

  14. Preparation and analysis of a {sup 109}Cd gamma source implanted into a silver single crystal

    SciTech Connect

    Alpatov, V.G.; Bizina, G.E.; Davydov, A.V.; Kartashov, G.R.; Sadovskii, A.A.

    1994-06-01

    Preparation of {sup 109}Cd gamma sources implanted by thermal diffusion into a single crystal of silver is described. The source is intended for experiments on Moessbauer excitation of the long-lived isomeric state of {sup 109}Ag with 88 keV energy. Two nondestructive methods are described for finding the depth of the implanted {sup 109}Cd atoms. One is a general-purpose method and can be used to study the diffusion of a wide class of radioactive atoms. The second method is useful only for the investigation of boundary distributions of the radioactive diffusant.

  15. Immediate provisional restoration of implant placed using flapless surgery and ridge mapping. Case report.

    PubMed

    Turkyilmaz, Ilser

    2011-04-01

    Loss of an anterior tooth as the result of trauma is relatively common, especially in the young. Orthodontic treatment is not always the definitive therapy of choice; instead, an implant can be placed to replace the missing tooth. This article describes the case of a 19-year-old woman whose maxillary left central incisor was replaced by an immediately restored dental implant, placed using flapless surgery. The implant achieved excellent primary stability, as determined by resonance frequency analysis, so it was immediately restored with a provisional acrylic resin crown in no centric occlusion. This case report supports the use of single implants for replacing a missing anterior tooth where esthetics are a priority. PMID:21735866

  16. Silver cluster formation in implanted Al{sub 2}O{sub 3} single crystals

    SciTech Connect

    Freire, F.L. Jr.; Broll, N.; Mariotto, G.

    1996-12-31

    Single crystals of sapphire were implanted at room temperature with 300 keV-Ag. The metal precipitate was characterized by a multitechnique approach including RBS, optical absorption and Raman spectroscopy. RBS measurements were used to determine the depth-profiles of the implanted ions. Ag depth profiles, derived from RBS are in good agreement with the results predicted by Monte Carlo simulations. Linear absorption spectroscopy has been used to characterize the effects of the ion fluence on the optical properties of the metal colloids in the UV-Vis region. The broad absorption band due to the surface plasmon resonance shows an appreciable red-shift when the fluence of bombarding ions increases. Raman scattering from acoustic vibrations of the silver clusters progressively shifts toward the laser frequency with increasing implantation dose. From low-frequency Raman spectra an evaluation of the average size of metal aggregates was derived.

  17. A new single chamber implantable defibrillator with atrial sensing: a practical demonstration of sensing and ease of implantation.

    PubMed

    Bnsch, Dietmar; Schneider, Ralph; Akin, Ibrahim; Nienaber, Cristoph A

    2012-01-01

    Implantable cardioverter-defibrillators (ICDs) terminate ventricular tachycardia (VT) and ventricular fibrillation (VF) with high efficacy and can protect patients from sudden cardiac death (SCD). However, inappropriate shocks may occur if tachycardias are misdiagnosed. Inappropriate shocks are harmful and impair patient quality of life. The risk of inappropriate therapy increases with lower detection rates programmed in the ICD. Single-chamber detection poses greater risks for misdiagnosis when compared with dual-chamber devices that have the benefit of additional atrial information. However, using a dual-chamber device merely for the sake of detection is generally not accepted, since the risks associated with the second electrode may outweigh the benefits of detection. Therefore, BIOTRONIK developed a ventricular lead called the Linox(SMART) S DX, which allows for the detection of atrial signals from two electrodes positioned at the atrial part of the ventricular electrode. This device contains two ring electrodes; one that contacts the atrial wall at the junction of the superior vena cava (SVC) and one positioned at the free floating part of the electrode in the atrium. The excellent signal quality can only be achieved by a special filter setting in the ICD (Lumax 540 and 740 VR-T DX, BIOTRONIK). Here, the ease of implantation of the system will be demonstrated. PMID:22395536

  18. Digital process for an implant-supported fixed dental prosthesis: A clinical report.

    PubMed

    Brandt, Jan; Lauer, Hans-Christoph; Peter, Thorsten; Brandt, Silvia

    2015-10-01

    A digital process is presented for an implant-supported single-tooth and a 3-unit fixed dental prosthesis (FDP) with customized abutments and monolithic prosthetic zirconia restorations. The digital impression on the implant level was made with a TRIOS intraoral scanner (3Shape). This process included the fabrication of an implant cast with the fused deposition modeling technique and a 3-dimensional printing process with integrated implant analogs. The process enabled the FDPs to be designed with CAD/CAM on the cast before patient contact. Designing a printed implant cast expands the use of the digital workflow in the dental field. PMID:26187099

  19. Implantation in the nine-banded armadillo: how does a single blastocyst form four embryos?

    PubMed

    Enders, A C

    2002-01-01

    In the course of a study on reproduction in the nine-banded armadillo, conceptuses between the beginning of implantation and primitive streak formation were examined to determine the manner of trophoblast differentiation during invasion of the endometrium and the sequence involved in formation of four identical quadruplets. The armadillo blastocyst implants in the fundic recess of the uterus. A single amnion and cup-shaped epiblastic plate are formed, and an exocelom develops between the amnion and trophoblast of the implantation site. Loss of the abembryonic trophoblast exposes both visceral and parietal endoderm to the uterine lumen, inverting the yolk sac. Continued expansion of the exocelom facilitates the intrusion of the forming conceptus into the uterine lumen and is accompanied by enlargement of the epiblastic plate. Separate areas of condensations of epiblast cells are the first indication of formation of the four identical quadruplets. The single layer of microvillous trophoblast with basal infoldings (designated absorptive trophoblast) is most likely to contribute extensively to movement of fluid into the exocelom. The resulting expansion of the exocelom not only enlarges the implantation site but also displaces the collapsing common amnion, limiting the amnion to the areas of the forming embryos. PMID:11869094

  20. High-sensitivity temperature sensing using an implanted single nitrogen-vacancy center array in diamond

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  1. Two Years Retrospective Evaluation of Overdenture Retained by Symphyseal Single Implant Using Two Types of Attachments

    PubMed Central

    Ismail, Hussien Abdelfattah; Mahrous, Ahmed I; Banasr, Fahad H; Soliman, Tarek A; Baraka, Yasser

    2015-01-01

    Background: This study was aimed to evaluate complete mandibular overdentures retained by a symphyseal single implant using ball and magnet attachments in both clinical and radiographic evaluation. Materials and Methods: Ten dental press fit titanium implants were installed in the lower jaws of completely edentulous patients according to two-stage surgical protocol. For each patient, one implant was installed in the symphyseal midline region, and left submerged and unloaded for 4 months. The patients were then divided into two equal groups. The first group received mandibular overdentures retained by ball and socket attachment. The second group received mandibular overdentures retained by magnet attachment. Both groups were supplied with conventional maxillary complete dentures. All patients were evaluated immediately after denture insertion, 6 months, and 12 months and after 24 months of overdenture insertion. Results: The study showed insignificant difference regarding the clinical condition and the marginal bone height changes in both groups during the follow-up period. Conclusion: Single implant retained overdenture with ball and socket or magnetic attachments was easy in construction, required less home care to maintain gingival health and give satisfactory clinical results. PMID:26124591

  2. Single-stage osseointegrated implants for nasal prosthodontic rehabilitation: A clinical report.

    PubMed

    de Carvalho, Bruna M D F; Freitas-Pontes, Karina M; de Negreiros, Wagner A; Verde, Marcus A R L

    2015-08-01

    Malignant tumors in the nasal region may be treated by means of invasive surgical procedures, with large facial losses. Nasal prostheses, retained by osseointegrated facial implants, instead of plastic surgery, will, in most patients, offer good biomechanical and cosmetic results. This clinical report describes the prosthetic rehabilitation of a patient with nasal cancer who had the entire nasal vestibule removed in a single-stage surgical procedure in order to shorten the rehabilitation time. The nasal prosthesis was built on a 3-magnet bar and was made of platinum silicone with intrinsic pigmentation, thereby restoring the patient's appearance and self-esteem. The authors concluded that single-stage implants may reduce the rehabilitation time to as little as 1 month, and the correct use of materials and techniques may significantly improve the nasal prosthesis. PMID:25976710

  3. Simultaneous Labyrinthectomy and Cochlear Implantation for Patients with Single-Sided Mnire's Disease and Profound Sensorineural Hearing Loss.

    PubMed

    Doobe, G; Ernst, A; Ramalingam, R; Mittmann, P; Todt, I

    2015-01-01

    Objective. To investigate the treatment outcome of a simultaneous labyrinthectomy and cochlear implantation in patients with single-sided Mnire's disease and profound sensorineural hearing loss. Study Design. Prospective study. Method. Five patients with single-sided Mnire's disease with active vertigo and functional deafness were included. In all cases, simultaneous cochlear implantation combined with labyrinthectomy surgery was performed. The outcome has been evaluated by the Dizziness Handicap Inventory (DHI) and speech recognition. Results. The combined labyrinthectomy and cochlear implantation led in all patients to a highly significant reduction of dizziness up to a restitutio ad integrum. After activation of the cochlear implant and rehabilitation, a mean monosyllabic speech understanding of 69% at 65?dB was observed. Conclusion. For patients with single-sided Mnire's disease and profound sensorineural hearing loss the simultaneous labyrinthectomy and cochlear implantation are efficient method for the treatment of vertigo as well as the rehabilitation of the auditory system. PMID:26380275

  4. Single Bilateral Dexamethasone Implant in Addition to Panretinal Photocoagulation and Oral Azathioprine Treatment in IRVAN Syndrome.

    PubMed

    Saatci, Ali Osman; Ayhan, Ziya; Take?, mer; Yaman, Aylin; Bajin, F Meltem Sylev

    2015-01-01

    The idiopathic retinal vasculitis, aneurysms and neuroretinitis (IRVAN) syndrome is a disease characterized by multiple retinal macroaneurysms, neuroretinitis and peripheral capillary nonperfusion. Visual loss may result from either ischemia-related complications or macular involvement. Treatment is not always rewarding. We report a case with stage 2 IRVAN syndrome who was successfully treated with a single bilateral intravitreal dexamethasone implant in addition to panretinal photocoagulation and systemic azathioprine treatment. PMID:25802506

  5. Single Bilateral Dexamethasone Implant in Addition to Panretinal Photocoagulation and Oral Azathioprine Treatment in IRVAN Syndrome

    PubMed Central

    Saatci, Ali Osman; Ayhan, Ziya; Take?, mer; Yaman, Aylin; Bajin, F. Meltem Sylev

    2015-01-01

    The idiopathic retinal vasculitis, aneurysms and neuroretinitis (IRVAN) syndrome is a disease characterized by multiple retinal macroaneurysms, neuroretinitis and peripheral capillary nonperfusion. Visual loss may result from either ischemia-related complications or macular involvement. Treatment is not always rewarding. We report a case with stage 2 IRVAN syndrome who was successfully treated with a single bilateral intravitreal dexamethasone implant in addition to panretinal photocoagulation and systemic azathioprine treatment. PMID:25802506

  6. A Monte Carlo binary collision model for BF{sub 2} implants into (100) single-crystal silicon

    SciTech Connect

    Yang, S.H.; Morris, S.J.; Tian, S.; Parab, K.; Obradovich, B.; Morris, M.; Tasch, A.F.; Snell, C.M.

    1996-11-01

    This paper describes a physically based Monte Carlo model and simulator for accurate simulation of BF{sub 2} ion implantation in (100) single-crystal silicon. An improved electronic stopping model and a damage generation model have been developed and implemented in the simulator. These new, physically based, models greatly improve the capability for predicting BF{sub 2} as-implanted profiles. The profile dependence on the implant tilt and rotation angles as well as on the implant dose and energy can be very well predicted over the energy range from 15 to 65 keV.

  7. An accurate Monte Carlo binary collision model for BF{sub 2} implants into (100) single-crystal silicon

    SciTech Connect

    Yang, S.H.; Morris, S.J.; Tian, S.

    1996-12-31

    In this paper is reported a physically based Monte Carlo model and simulator for accurate simulation of BF, ion implantation in (100) single-crystal silicon. An improved electronic stopping model and a cumulative damage generation model have been developed and implemented in the simulator. These new physically based models greatly improve the capability for predicting BF, as-implanted profiles. The profile dependence on the implant tilt and rotation angles as well as on the implant dose and energy can be very well predicted over the energy range 15keV-65keV.

  8. Tooth-Bleaching: AReview of the Efficacy and Adverse Effects of Various Tooth Whitening Products.

    PubMed

    Majeed, Abdul; Farooq, Imran; Grobler, Sias R; Rossouw, R J

    2015-12-01

    Tooth bleaching (whitening) is one of the most common and inexpensive method for treating discolouration of teeth. Dental aesthetics, especially tooth colour, is of great importance to majority of the people; and discolouration of even a single tooth can negatively influence the quality of life. Therefore, a review of the literature was carried out (limited to aesthetic tooth-bleaching) to provide a broad overview of the efficacy and adverse effects of various tooth whitening products on soft and hard oral tissues. PMID:26691365

  9. Nanofabrication processes for single-ion implantation of silicon quantum computer devices

    NASA Astrophysics Data System (ADS)

    McKinnon, Rita P.; Stanley, Fay E.; Buehler, Tilo M.; Gauja, Eric; Peceros, Katia; Macks, Linda D.; Mitic, Mladen; Chan, Victor; Dzurak, Andrew S.; Clark, Robert G.; Yang, Changyi; Jamieson, David N.; Prawer, Steven D.

    2001-11-01

    We describe progress in a range of nanofabrication processes for the production of silicon-based quantum computer devices. The processes are based upon single-ion implantation to place phosphorus-31 atoms in accurate locations, precisely self-aligned to metal control gates. These fabrication schemes involve multi-layer resist and metal structures, electron beam lithography and multi-angled aluminium shadow evaporation. The key feature of all fabrication schemes is a gate pattern defined in a resist structure using electron beam lithography, used in conjunction with a second pattern written in another resist layer. The locations where the two patterns overlap define channels down to the substrate through which ions can be implanted, with the remaining metal/resist structure behaving as a mask. Further processing on the resist structures allows for deposition of the control gates and read-out structures. Central to this process is a new technique which allows for control of the implantation process at a single-ion level.

  10. Fracture behavior of straight or angulated zirconia implant abutments supporting anterior single crowns.

    PubMed

    Nothdurft, Frank P; Doppler, Klaus E; Erdelt, Kurt J; Knauber, Andreas W; Pospiech, Peter R

    2011-04-01

    The aim of the study was to evaluate the influence of artificial aging on the fracture behavior of straight and angulated zirconia implant abutments (ZirDesign; Astra Tech, Mlndal, Sweden) supporting anterior single crowns (SCs). Four different test groups (n?=?8) representing anterior SCs were prepared. Groups 1 and 2 simulated a clinical situation with an ideal implant position (left central incisor) from a prosthetic point of view, which allows for the use of a straight, prefabricated zirconia abutment. Groups 3 and 4 simulated a situation with a compromised implant position, requiring an angulated (20) abutment. OsseoSpeed implants (Astra Tech) 4.5 mm in diameter and 13 mm in length were used to support the abutments. The SCs (chromium cobalt alloy) were cemented with glass ionomer cement. Groups 2 and 4 were thermomechanically loaded (TCML?= 1.2 10?; 10,000 5/55) and subjected to static loading until failure. Statistical analysis of force data at the fracture site was performed using nonparametric tests. All samples tested survived TCML. Artificial aging did not lead to a significant decrease in load-bearing capacity in either the groups with straight abutments or the groups with angulated abutments. The restorations that utilized angulated abutments exhibited higher fracture loads than the restorations with straight abutments (group 1, 280.25 30.45 N; group 2, 268.88 38.00 N; group 3, 355.00 24.71 N; group 4, 320.71 78.08 N). This difference in load-bearing performance between straight and angulated abutments was statistically significant (p = 0.000) only when no artificial aging was employed. The vast majority of the abutments fractured below the implant shoulder. PMID:20084415

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

    SciTech Connect

    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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    ZnO single crystal samples were implanted by oxygen with the energy of 150keV. After the pretreatment of hydrogen peroxide, 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& circ; C , 650& circ; C and 750& circ; C. Three peaks were identified in the DLTS spectra of the 900& circ; C 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& circ; C were also investigated. This work was supported by the RGC HKSAR under the GRF scheme (No. 703108P).

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  14. Experimental Studies of Defects, Implants, and Their Processes in Ion-Irradiated Silicon Carbide Single Crystals

    SciTech Connect

    Jiang, Weilin; Weber, William J.

    2003-11-17

    This chapter reviews the experimental results, obtained by the authors, on the disorder accumulation, disorder recovery, and behavior of implants in ion-irradiated 6H silicon carbide (6H-SiC) single crystals. The disorder on both the Si and C sublattices has been studied using a combination of Rutherford backscattering spectrometry and nuclear reaction analysis in channeling geometry. Damage states have been analyzed based on multiaxial channeling along different orientations. The surface morphologies and damage states have been examined using electron microscopy. Damage accumulation has been investigated as a function of ion fluence, irradiation temperature, ion species, and dose rate. The results of both isochronal and isothermal annealing, as well as dynamic recovery induced by energetic ion beams are summarized. In addition, the behavior of noble-metal implants and gas species in SiC are discussed.

  15. Immediate placement of single implant simultaneously with immediate loading in a fresh socket associated to periapical infection: A clinical case report.

    PubMed

    Agustín-Panadero, Rubén; Serra-Pastor, Blanca; Chust-López, Cesar; Fons-Font, Antonio; Ferreiroa, Alberto

    2015-02-01

    Early restoration of the masticatory function, phonatory and aesthetics is some of the current goals of the therapy based on endosseous implants. Facing the classic protocols of implant insertion, which recommend a period of several months between extraction and implant placement, alternatives have been developed that demonstrate that immediate implant placement after tooth extraction permits adequate osseointegration, even in those cases where there is a periapical disease. The immediate restoration of implants after placement is a possibility where aesthetic requirements are high. This article presents a case with immediate implant placement and immediate loading of a first upper premolar with prior periapical pathology due to a vertical fracture. The immediate prosthetic was performed using the extracted crown, which is adapted to be attached to a titanium temporary abutment using a resin cement. After a 4 month healing period work began on the final prosthetic crown. The screw crown was made of zirconium oxide with a covering feldspathic ceramic. At the 12-month follow-up, there were no mechanical or biological complications. The patient gave high satisfaction marks for the overall treatment, giving visual analogue scale score of nine. Immediate post-extraction implants have arisen as an alternative to traditional implants on completely healed bone. Their main aim is to reduce treatment time and number of surgical procedures, along with other objectives such as reduced bone re-absorption and improved aesthetics. Key words:Post-extraction implants, immediate loading prosthetic, implant-retained prosthesis, periapical disease, vertical fracture. PMID:25810833

  16. Immediate placement of single implant simultaneously with immediate loading in a fresh socket associated to periapical infection: A clinical case report

    PubMed Central

    Agustn-Panadero, Rubn; Serra-Pastor, Blanca; Chust-Lpez, Cesar; Fons-Font, Antonio; Ferreiroa, Alberto

    2015-01-01

    Early restoration of the masticatory function, phonatory and aesthetics is some of the current goals of the therapy based on endosseous implants. Facing the classic protocols of implant insertion, which recommend a period of several months between extraction and implant placement, alternatives have been developed that demonstrate that immediate implant placement after tooth extraction permits adequate osseointegration, even in those cases where there is a periapical disease. The immediate restoration of implants after placement is a possibility where aesthetic requirements are high. This article presents a case with immediate implant placement and immediate loading of a first upper premolar with prior periapical pathology due to a vertical fracture. The immediate prosthetic was performed using the extracted crown, which is adapted to be attached to a titanium temporary abutment using a resin cement. After a 4 month healing period work began on the final prosthetic crown. The screw crown was made of zirconium oxide with a covering feldspathic ceramic. At the 12-month follow-up, there were no mechanical or biological complications. The patient gave high satisfaction marks for the overall treatment, giving visual analogue scale score of nine. Immediate post-extraction implants have arisen as an alternative to traditional implants on completely healed bone. Their main aim is to reduce treatment time and number of surgical procedures, along with other objectives such as reduced bone re-absorption and improved aesthetics. Key words:Post-extraction implants, immediate loading prosthetic, implant-retained prosthesis, periapical disease, vertical fracture. PMID:25810833

  17. Chick tooth induction revisited.

    PubMed

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

    2009-07-15

    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

  18. Evaluation of bone remodeling around single dental implants of different lengths: a mechanobiological numerical simulation and validation using clinical data.

    PubMed

    Sotto-Maior, Bruno Salles; Mercuri, Emílio Graciliano Ferreira; Senna, Plinio Mendes; Assis, Neuza Maria Souza Picorelli; Francischone, Carlos Eduardo; Del Bel Cury, Altair Antoninha

    2016-05-01

    Algorithmic models have been proposed to explain adaptive behavior of bone to loading; however, these models have not been applied to explain the biomechanics of short dental implants. Purpose of present study was to simulate bone remodeling around single implants of different lengths using mechanoregulatory tissue differentiation model derived from the Stanford theory, using finite elements analysis (FEA) and to validate the theoretical prediction with the clinical findings of crestal bone loss. Loading cycles were applied on 7-, 10-, or 13-mm-long dental implants to simulate daily mastication and bone remodeling was assessed by changes in the strain energy density of bone after a 3, 6, and 12 months of function. Moreover, clinical findings of marginal bone loss in 45 patients rehabilitated with same implant designs used in the simulation (n = 15) were computed to validate the theoretical results. FEA analysis showed that although the bone density values reduced over time in the cortical bone for all groups, bone remodeling was independent of implant length. Clinical data showed a similar pattern of bone resorption compared with the data generated from mathematical analyses, independent of implant length. The results of this study showed that the mechanoregulatory tissue model could be employed in monitoring the morphological changes in bone that is subjected to biomechanical loads. In addition, the implant length did not influence the bone remodeling around single dental implants during the first year of loading. PMID:26249362

  19. Preparation of C 60 single crystalline thin film by ionized cluster beam deposition and ion implantation into single crystalline C 60 thin film

    NASA Astrophysics Data System (ADS)

    Isoda, Satoru; Kawakubo, Hiroaki; Nishikawa, Satoshi; Wada, Osamu

    1996-05-01

    We have succeeded in preparing single crystalline C 60 thin film of a lateral extension in the order of several millimeters on mica by ionized cluster beam (ICB) deposition. During the growth process, planar dendrite-like single crystalline islands were observed by an atomic force microscope (AFM). It was concluded from reflection high-energy electron diffraction (RHEED) and transmission electron diffraction (TED) analyses that these islands grow hetero-epitaxially on mica. As the deposition process continues, the single crystalline islands coalesce and finally form a giant single crystal without grain boundaries between the former islands. This layered dendrite-like crystal growth is considered to be due to the ICB process, namely, ionizing molecules and accelerating them. Furthermore, the effect of ion (P +, B +, Ar +) implantation into C 60 thin films on the molecular structure and the conductivity has been studied under various implantation conditions. It was found from the analyses of FT-IR and Raman spectroscopies that the soccer-ball-like structure of C 60 changes into a diamond-like carbon (DLC) structure with an implantation energy higher than 40 keV, whereas the structure undergoes virtually no change with 10 keV implantation. As for conductivity changes under the lower implantation energy condition, the minimum dose of P + ions required to increase the conductivity from the non-doped value (10 12 cm -2) is 10 times lower than in the case of Ar + implantation. The conductivity change for the P + implantation could be explained satisfactorily not only by the effect of chemically-modified C 60 but also by the effect of a charge-transfer state between C 60 and implanted ions. It was concluded from these results that the conductivity of the C 60 film can be controlled over a wide range based on the carrier generation mechanism, which depends on the implantation conditions.

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

    PubMed Central

    Rutherglen, Christopher

    2009-01-01

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

  1. Effect of ion fluence on the surface morphology of single crystal magnesium oxide implanted with xenon

    SciTech Connect

    Jiang, W.; Norton, M.G.; Poker, D.B.

    1995-11-01

    The surface morphology of (001)-oriented single crystal magnesium oxide (MgO) implanted with xenon ions has been examined using atomic force microscopy. It was found that at the lowest fluence used in this study (1.0{times}10{sup 14}/cm{sup 2}), slight roughening of the (001) surface occurred. The magnitude of this roughening remained fairly constant with increases in fluence in the range 1.0{times}10{sup 14}/cm{sup 2} to 3.0{times}10{sup 16}/cm{sup 2}. Implantation at fluences of {ge}1.0{times}10{sup 17}/cm{sup 2} caused significant surface roughening with the concomitant formation of micro-sized blisters. The appearance of some of these blisters resembles the rosette pattern which is also observed when the cleaved surfaces of MgO crystals are etched following indentation using a spherical indenter. This observation suggests that these blisters are formed by the growth of xenon inclusions, during implantation, by a dislocation loop punching mechanism. {copyright} 1995 {ital Materials} {ital Research} {ital Society}.

  2. Mechanical behavior of single-layer ceramized zirconia abutments for dental implant prosthetic rehabilitation

    PubMed Central

    Jimnez-Melendo, Manuel; Llena-Blasco, Oriol; Bruguera, August; Llena-Blasco, Jaime; Yez-Vico, Rosa-Mara; Garca-Caldern, Manuel; Vaquero-Aguilar, Cristina; Velzquez-Cayn, Roco; Gutirrez-Prez, Jos-Luis

    2014-01-01

    Objectives: This study was undertaken to characterize the mechanical response of bare (as-received) and single-layer ceramized zirconia abutments with both internal and external connections that have been developed to enhanced aesthetic restorations. Material and Methods: Sixteen zirconia implant abutments (ZiReal Post, Biomet 3i, USA) with internal and external connections have been analyzed. Half of the specimens were coated with a 0.5mm-thick layer of a low-fusing fluroapatite ceramic. Mechanical tests were carried out under static (constant cross-head speed of 1mm/min until fracture) and dynamic (between 100 and 400N at a frequency of 1Hz) loading conditions. The failure location was identified by electron microscopy. The removal torque of the retaining screws after testing was also evaluated. Results: The average fracture strength was above 300N for all the abutments, regardless of connection geometry and coating. In most of the cases (94%), failure occurred by abutment fracture. No significant differences were observed either in fatigue behavior and removal torque between the different abutment groups. Conclusions: Mechanical behavior of Zireal zirconia abutments is independent of the type of internal/external connection and the presence/absence of ceramic coating. This may be clinically valuable in dental rehabilitation to improve the aesthetic outcome of zirconia-based dental implant systems. Key words:Dental implant, zirconia, ceramic structure, mechanical properties. PMID:25674313

  3. Fast and Successful Management of Intraocular Inflammation with a Single Intravitreal Dexamethasone Implant.

    PubMed

    Pleyer, Uwe; Klamann, Matthias; Laurent, Thierry-Jens; Mnz, Martin; Hazirolan, Dicle; Winterhalter, Sibylle; Thurau, Stephan R

    2014-11-21

    Purpose: To investigate the efficacy and safety of a single dexamethasone intravitreal implant (Ozurdex, 700 g). Methods: In this prospective noncomparative case series, 84 patients (54 females) received a dexamethasone intravitreal implant. At weeks 4, 12 and 24 after the injection, vitreous haze, macular thickness and best corrected visual acuity (BCVA) were assessed and adverse events reported. Results: Clearance of vitreous haze could be achieved after 4 weeks in 61% of all eyes (p < 0.001) and remained significant until week 24 (p < 0.001). This was paralleled by a reduction of central retinal thickness after 4 (p < 0.001), 12 (p < 0.001) and 24 weeks (p < 0.006). Significant and fast improvement of BCVA was already achieved after 4 weeks (p < 0.001) but vanished by week 24. Intraocular pressure reached ?35 mm Hg in 3 eyes and was significantly more frequent in intermediate uveitis compared to posterior uveitis (p < 0.016). Conclusions: The dexamethasone implant is effective in controlling intraocular posterior segment inflammation and reduces central retinal thickness fast and effectively. 2014 S. Karger AG, Basel. PMID:25428335

  4. Strength and mode of failure of single implant all-ceramic abutment restorations under static load.

    PubMed

    Tripodakis, A P; Strub, J R; Kappert, H F; Witkowski, S

    1995-01-01

    The strength and mode of failure of three different designs of custom-made all-ceramic implant abutments fabricated by milling of In-Ceram sintered ceramic blocks were compared with the conventional CeraOne system under static load. Four test groups were formed with different locations of abutment screws. In three test groups, In-Ceram crowns were fabricated for placement on the all-ceramic abutments, and in one test group, a veneer porcelain was fired directly on the abutment; crowns in the control group were fabricated using the CeraOne system. Ten-mm-long Brnemark implants were placed into a brass block that allowed loading at a 30-degree angle to the long axis. The test group in which the veneer porcelain was fired directly on the all-ceramic abutments was the weakest, and it showed fractures at a mean value of 236 N. The fracture strength of the three other test groups was dependent on the extension of the crown margin relative to the location of the screw head. The test group that had the screw on the top compressing the entire ceramic abutment showed a mean value of 422 N that was similar to the results that were achieved with the CeraOne system (427 N). The weakest link in the all-ceramic single implant restorations was the abutment screw in which the bending began at approximately 190 N. PMID:10348596

  5. Lattice location and annealing behaviour of helium atoms implanted in uranium dioxide single crystals

    NASA Astrophysics Data System (ADS)

    Belhabib, T.; Desgardin, P.; Sauvage, T.; Erramli, H.; Barthe, M. F.; Garrido, F.; Carlot, G.; Nowicki, L.; Garcia, P.

    2015-12-01

    Helium behaviour in irradiated uranium dioxide may play an important role in the mechanical stability of nuclear fuels during and after its use in nuclear power plants. Helium migration mechanisms in bulk UO2 have already been the subject of theoretical studies but there is a lack of experimental data relating to the most stable location in the crystal. To this end, we have studied uranium dioxide samples implanted with helium ions at low fluence before and after thermal annealing in the range 600 and 800 °C. UO2 single crystals were implanted with 50 keV-3He ions at the fluence of 1 × 1015 at cm-2 and the location in the lattice of helium atoms was investigated using NRA (Nuclear Reaction Analysis) based on the reaction of 3He with deuterons (3He (d,p) 4He) in a channelling mode, recording angular scans across axes and planes. Furthermore, the uranium sub-lattice was analysed by the classical RBS method. After implantation, the experimental angular scans recorded across the main crystallographic axes and along major planes show that the helium atoms in their large majority occupy octahedral interstitial sites. No modification of the occupied crystallographic site was found after annealing at 600 °C. Conversely, no crystallographic relationship between matrix and helium signals was revealed following annealing at 800 °C. The latter feature is likely related to the clustering of implanted helium atoms into gas-filled bubbles. These experimental results have been quantified and interpreted using Monte Carlo simulations with the McChasy code.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  7. Development of a solid-state quantum computer: Single electron transistors and highly charged ion implantation

    NASA Astrophysics Data System (ADS)

    Park, Sang Joon

    2004-12-01

    A proposal to manipulate phosphorous quantum bits in silicon has been studied as a new concept of the next generation computing. Quantum information systems in a silicon structure have a lot of advantages in terms of the scalability and the usage of advanced silicon technology. We studied solid-state quantum bit (qubit) schemes of dual phosphorous atom interactions in the crystalline silicon matrix. In this thesis, the developmental processes and the results from this study will be shown. This experimental approach includes a single ion implantation scheme into a registered position using highly charged ion sources and a single electron transistor read-out scheme using nanowires based on silicon fabrication technology. Firstly, the single ion implantation scheme is based on slow (slower than the Bohr velocity: v < vBohr = 2.2 x 106 m/s) highly charged ions (SHCIs) extracted from the Electron Beam Ion Trap (EBIT) at the Lawrence Berkeley National Lab (LBNL). HCIs lose their electrons in an ion trap coupled with a high current density electron beam. An ion with few electrons can have a potential energy in a range of 10 to 100 keV The ion releases its potential energy in a time scale of 10 femto seconds (ultra-fast interaction) on a solid surface. This effect leads to electron emissions from the surface, which is proportional to the released potential energy. Hence, the efficiency of detecting single ions is higher than for singly-charged ions. Secondly, we have formed 10--30 nm wires on a silicon wafer as a sensor to detect the phosphorous atom interactions inside the silicon solid matrix. Electron beam lithography (EBL) technology can pattern the wire size down to 10 nm scale. In this device, the sensitivity of a nanowire plays an important role in implementing the solid-state quantum computer.

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

    PubMed Central

    Kim, Young-Kyun; Lim, Sung-Chul

    2014-01-01

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

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

    PubMed

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

    2013-10-16

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

  10. Modulation frequency discrimination with single and multiple channels in cochlear implant users.

    PubMed

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

    2015-06-01

    Temporal envelope cues convey important speech information for cochlear implant (CI) users. Many studies have explored CI users' single-channel temporal envelope processing. However, in clinical CI speech processors, temporal envelope information is processed by multiple channels. Previous studies have shown that amplitude modulation frequency discrimination (AMFD) thresholds are better when temporal envelopes are delivered to multiple rather than single channels. In clinical fitting, current levels on single channels must often be reduced to accommodate multi-channel loudness summation. As such, it is unclear whether the multi-channel advantage in AMFD observed in previous studies was due to coherent envelope information distributed across the cochlea or to greater loudness associated with multi-channel stimulation. In this study, single- and multi-channel AMFD thresholds were measured in CI users. Multi-channel component electrodes were either widely or narrowly spaced to vary the degree of overlap between neural populations. The reference amplitude modulation (AM) frequency was 100Hz, and coherent modulation was applied to all channels. In Experiment 1, single- and multi-channel AMFD thresholds were measured at similar loudness. In this case, current levels on component channels were higher for single-than for multi-channel AM stimuli, and the modulation depth was approximately 100% of the perceptual dynamic range (i.e., between threshold and maximum acceptable loudness). Results showed no significant difference in AMFD thresholds between similarly loud single- and multi-channel modulated stimuli. In Experiment 2, single- and multi-channel AMFD thresholds were compared at substantially different loudness. In this case, current levels on component channels were the same for single- and multi-channel stimuli ("summation-adjusted" current levels) and the same range of modulation (in dB) was applied to the component channels for both single- and multi-channel testing. With the summation-adjusted current levels, loudness was lower with single than with multiple channels and the AM depth resulted in substantial stimulation below single-channel audibility, thereby reducing the perceptual range of AM. Results showed that AMFD thresholds were significantly better with multiple channels than with any of the single component channels. There was no significant effect of the distribution of electrodes on multi-channel AMFD thresholds. The results suggest that increased loudness due to multi-channel summation may contribute to the multi-channel advantage in AMFD, and that overall loudness may matter more than the distribution of envelope information in the cochlea. PMID:25746914

  11. Replacing a Missing Tooth

    MedlinePLUS

    ... the missing lateral incisor. During orthodontic treatment, an artificial tooth may be attached to the orthodontic wire ... braces are removed, a removable retainer with an artificial tooth serves to maintain the space and improve ...

  12. Stress Distribution in Single Dental Implant System: Three-Dimensional Finite Element Analysis Based on an In Vitro Experimental Model.

    PubMed

    Rezende, Carlos Eduardo Edwards; Chase-Diaz, Melody; Costa, Max Doria; Albarracin, Max Laurent; Paschoeto, Gabriela; Sousa, Edson Antonio Capello; Rubo, Jos Henrique; Borges, Ana Flvia Sanches

    2015-10-01

    This study aimed to analyze the stress distribution in single implant system and to evaluate the compatibility of an in vitro model with finite element (FE) model. The in vitro model consisted of Brnemark implant; multiunit set abutment of 5 mm height; metal-ceramic screw-retained crown, and polyurethane simulating the bone. Deformations were recorded in the peri-implant region in the mesial and distal aspects, after an axial 300 N load application at the center of the occlusal aspect of the crown, using strain gauges. This in vitro model was scanned with micro CT to design a three-dimensional FE model and the strains in the peri-implant bone region were registered to check the compatibility between both models. The FE model was used to evaluate stress distribution in different parts of the system. The values obtained from the in vitro model (20-587 ??) and the finite element analysis (81-588 ??) showed agreement among them. The highest stresses because of axial and oblique load, respectively were 5.83 and 40 MPa for the cortical bone, 55 and 1200 MPa for the implant, and 80 and 470 MPa for the abutment screw. The FE method proved to be effective for evaluating the deformation around single implant. Oblique loads lead to higher stress concentrations. PMID:26192032

  13. Single-Port Parastomal Hernia Repair by Using 3-D Textile Implants

    PubMed Central

    Emmanuel, Klaus; Schrittwieser, Rudolf

    2014-01-01

    Background: Parastomal hernias (PSHs) are a frequent complication and remain a surgical challenge. We present a new option for single-port PSH repair with equilateral stoma relocation using preshaped, prosthetic 3-dimensional implants and flat mesh insertion in intraperitoneal onlay placement for additional augmentation of the abdominal wall. Methods: We describe our novel technique in detail and performed an analysis of prospectively collected data from patients who underwent single-port PSH repair, focusing on feasibility, conversions, and complications. Results: From September 2013 to January 2014, 9 patients with symptomatic PSHs were included. Two conversions to reduced-port laparoscopy using a second 3-mm trocar were required because of difficult adhesiolysis, dissection, and reduction of the hernia sac content. No major intra- or postoperative complications or reoperations were encountered. One patient incurred a peristomal wound healing defect that could be treated conservatively. Conclusion: We found that single-port PSH repair using preshaped, elastic 3-dimensional devices and additional flat mesh repair of the abdominal wall is feasible, safe, and beneficial, relating to optimal coverage of unstable stoma edges with wide overlap to all sides and simultaneous augmentation of the midline in the IPOM technique. The stoma relocation enables prolapse treatment and prevention. The features of a modular and rotatable multichannel port system offer benefits in clear dissection ongoing from a single port. Long-term follow-up data on an adequate number of patients are awaited to examine efficacy. PMID:25392655

  14. Fractured tooth (image)

    MedlinePLUS

    A tooth can be chipped or fractured during an accident or a bad fall. A tooth that is chipped or not badly fractured can usually be handled on a nonemergency basis. A tooth that is badly fractured may have exposed nerve ...

  15. Evaluation of Hi-Tec Implant Restoration in Mandibular First Molar Region- A Prospective Clinical Study

    PubMed Central

    Sreeram, Roopa Rani. S.; Prasad, L Krishna; Chakravarthi, P Srinivas; Devi, Naga Neelima; Sreeram, Sanjay Krishna

    2015-01-01

    Background and Aims Missing teeth lead to loss of structural balance, inefficient function, poor aesthetics and psychological effects on human beings, which needs restoration for normal contour, function and aesthetics. Several natural or synthetic substitutes are being used for replacement of missing tooth since centuries. Implants are the latest modality of replacement. So, the study was aimed to assess clinical success rate of Hi-Tec implant; which is economical and new in market. Results of the study will help clinician for appropriate implant selection. Materials and Methods The study included 10 patients from 19 to 31 years and needed restoration of missing mandibular first molar. Restoration had done using Hi Tec Single-tooth implants with metal-ceramic single crown prosthesis after three months of osseointegration. The implants were evaluated clinically (bleeding on probing, probing depth, implant mobility- periotest) and radiographically (marginal bone loss and peri-implant radiolucency) for six years. The observers were blinded for the duration of the study to prevent bias. Results All the patients had uneventful post-surgical healing. No bleeding on probing, Implant mobility, peri-implant radiolucency with minimal marginal bone loss and constant probing depths were observed well within the normal range during follow-up periods. Conclusion Two stage single-tooth Hi Tec implant restoration can be used as a successful treatment modality for replacing mandibular first molar in an economic way. However, these results were obtained after 6 years of follow up with a smaller sample size, so long term multi center studies with a larger sample size is recommended for the predictability of success rate conclusively. PMID:26436053

  16. Quantification of in vivo implant wear in total knee replacement from dynamic single plane radiography

    NASA Astrophysics Data System (ADS)

    Teeter, Matthew G.; Seslija, Petar; Milner, Jaques S.; Nikolov, Hristo N.; Yuan, Xunhua; Naudie, Douglas D. R.; Holdsworth, David W.

    2013-05-01

    An in vivo method to measure wear in total knee replacements was developed using dynamic single-plane fluoroscopy. A dynamic, anthropomorphic total knee replacement phantom with interchangeable, custom-fabricated components of known wear volume was created, and dynamic imaging was performed. For each frame of the fluoroscopy data, the relative location of the femoral and tibial components were determined, and the apparent intersection of the femoral component with the tibial insert was used to calculate wear volume, wear depth, and frequency of intersection. No difference was found between the measured and true wear volumes. The precision of the measurements was ±39.7 mm3 for volume and ±0.126 mm for wear depth. The results suggest the system is capable of tracking wear volume changes across multiple time points in patients. As a dynamic technique, this method can provide both kinematic and wear measurements that may be useful for evaluating new implant designs for total knee replacements.

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

    SciTech Connect

    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

    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.

  18. Quantification of in vivo implant wear in total knee replacement from dynamic single plane radiography.

    PubMed

    Teeter, Matthew G; Seslija, Petar; Milner, Jaques S; Nikolov, Hristo N; Yuan, Xunhua; Naudie, Douglas D R; Holdsworth, David W

    2013-05-01

    An in vivo method to measure wear in total knee replacements was developed using dynamic single-plane fluoroscopy. A dynamic, anthropomorphic total knee replacement phantom with interchangeable, custom-fabricated components of known wear volume was created, and dynamic imaging was performed. For each frame of the fluoroscopy data, the relative location of the femoral and tibial components were determined, and the apparent intersection of the femoral component with the tibial insert was used to calculate wear volume, wear depth, and frequency of intersection. No difference was found between the measured and true wear volumes. The precision of the measurements was 39.7 mm(3) for volume and 0.126 mm for wear depth. The results suggest the system is capable of tracking wear volume changes across multiple time points in patients. As a dynamic technique, this method can provide both kinematic and wear measurements that may be useful for evaluating new implant designs for total knee replacements. PMID:23552105

  19. Nature of Defects Induced by Au Implantation in Hexagonal Silicon Carbide Single Crystals

    SciTech Connect

    Gentils, Aurelie; Barthe, Marie-France; Egger, Werner; Sperr, Peter

    2009-03-10

    Pulsed-slow-positron-beam-based positron lifetime spectroscopy was used to investigate the nature of vacancy defects induced by 20 MeV Au implantation in single crystals 6H-SiC. Preliminary analysis of the data shows that at lower fluence, below 10{sup 14} cm{sup -2}, a positron lifetime of 220 ps has been obtained: it could be associated with the divacancy V{sub Si}-V{sub C} in comparison with the literature. At higher fluence, above 10{sup 15} cm{sup -2}, a positron lifetime of 260-270 ps, increasing with the incident positron energy, has been observed after decomposition of the lifetime spectra. By comparison with lifetime calculations, open-volumes such as quadrivacancy (V{sub Si}-V{sub C}){sub 2} clusters could be associated with this value.

  20. A Prospective Study of Early Loaded Single Implant-Retained Mandibular Overdentures: Preliminary One-Year Results

    PubMed Central

    El-Sheikh, Ali M.; Shihabuddin, Omar F.; Ghoraba, Sahar M. F.

    2012-01-01

    Purpose. To investigate the predictability of simplifying mandibular overdenture treatment using one-stage surgery and early prosthetic loading of a single implant. Materials and Methods. Twenty edentulous patients with problematic existing mandibular dentures were treated. A single implant with a chemically modified surface (SLActive, Straumann AG, Basel, Switzerland) was placed into the mandibular midline. The patients were recalled at 3, 6 and 12 months. Clinical assessments and marginal bone loss using standardized radiographs were recorded. All complications, failures and maintenance were noted. Visual analog-scale questionnaires were used to record patient satisfaction in five categories. ANOVA was used to determine differences between means of marginal bone loss and different categories of patient staisfaction (P = 0.05). Results. The 20 early loaded implants were all surviving at the 12-month recall. All implants showed less than 1?mm of marginal bone loss by the end of the 1-year with a significant increase during the follow-up period. Few prosthetic problems were reported. Patient satisfaction was high with a significant increase in all comfort and functional parameters. Conclusions. These preliminary 1-year results indicate that early loading of a single chemically modified surface implant used to retain a mucosa-borne mandibular overdenture is a safe, reliable, and cost-effective treatment. PMID:22505895

  1. Clinical comparison of 2 implantation systems for single-level cervical disk replacement.

    PubMed

    Shi, Rui; Li, Juan; Liu, Hao; Ding, Chen; Hu, Tao; Li, Tao; Gong, Quan

    2014-02-01

    The safety and effectiveness of 2 implantation systems for single-segment cervical disk replacement-the Bryan Cervical Disc System (Medtronic Inc, Minneapolis, Minnesota) and the ACCEL system (Medtronic Inc)-have not been clinically compared. A prospective, nonrandomized controlled study in consecutive patients with a minimum 2-year follow-up was performed. Fifty patients with single-level cervical disk degeneration who responded poorly to conservative treatment and underwent Bryan Cervical Disc replacement were involved. Fifty patients were included (24 in group A [Bryan Cervical Disc System] and 26 in group B [ACCEL system]).The patients' visual analog scale scores, Neck Disability Index (NDI) scores, Short Form 36 (SF-36) scores, Odom scores, operative time, blood loss, and complications were compared. Patients' baseline statuses were similar (P>.05). Visual analog scale for neck and arm pain, NDI, and SF-36 were significantly improved postoperatively (P<.05) in both groups, and no clinical differences were found between the groups (P>.05). All Odom scores were better than good. Mean operative time and average blood loss in group A (17342.5 minutes and 250159.8 mL, respectively), were both significantly higher than the values in group B (137.519.3 minutes and 138.186.7 mL, respectively) (P<.05). Complications included intraoperative bleeding, temporary throat discomfort, and slight migration of the prosthesis; there was no significant difference in the total complication rates between the 2 groups (P>.05). The 2 implantation systems displayed equal clinical effectiveness and safety, but the ACCEL system appears to have the advantages of shorter operative time and less blood loss. PMID:24679203

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

    PubMed Central

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  4. Single crystalline BaTiO{sub 3} thin films synthesized using ion implantation induced layer transfer

    SciTech Connect

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

    2007-10-01

    Layer transfer of BaTiO{sub 3} thin films onto silicon-based substrates has been investigated. Hydrogen and helium ions were co-implanted to facilitate ion-implantation-induced layer transfer of films from BaTiO{sub 3} single crystals. From thermodynamic equilibrium calculations, we suggest that the dominant species during cavity nucleation and growth are H{sub 2}, H{sup +}, H{sub 2}O, Ba{sup 2+} and Ba-OH, and that the addition of hydrogen to the Ba-Ti-O system can effectively suppress volatile oxide formation during layer transfer and subsequent annealing. After ion implantation, BaTiO{sub 3} layers contain microstructural defects and hydrogen precipitates in the lattice, but after layer transfer, the single crystal is found to be stoichiometric. Using direct wafer bonding and layer splitting, single crystal BaTiO{sub 3} thin films were transferred onto amorphous Si{sub 3}N{sub 4} and Pt substrates. Micro-Raman spectroscopy indicated that the density of defects generated by ion implantation in BaTiO{sub 3} can be significantly reduced during post-transfer annealing, returning the transferred layer to its single crystal state. Characterization using piezoresponse force microscopy shows that the layer transferred thin films are ferroelectric, with domain structures and piezoresponse characteristics similar to that of bulk crystals.

  5. Methods for implantation of micro-wire bundles and optimization of single/multiunit recordings from human mesial temporal lobe

    PubMed Central

    Misra, A; Burke, JF; Ramayya, A; Jacobs, J; Sperling, MR; Moxon, KA; Kahana, MJ; Evans, JJ; Sharan, AD

    2014-01-01

    Objective The authors report methods developed for the implantation of micro-wire bundles into mesial temporal lobe structures and subsequent single neuron recording in epileptic patients undergoing in-patient diagnostic monitoring. This is done with the intention of lowering the perceived barriers to routine single neuron recording from deep brain structures in the clinical setting. Approach Over a 15 month period, 11 patients were implanted with platinum micro-wire bundles into mesial temporal structures. Protocols were developed for A) monitoring electrode integrity through impedance testing, B) ensuring continuous 24-7 recording, C) localizing micro-wire position and “splay” pattern and D) monitoring grounding and referencing to maintain the quality of recordings. Main Result Five common modes of failure were identified: 1) broken micro-wires from acute tensile force, 2) broken micro-wires from cyclic fatigue at stress points, 3) poor in-vivo micro-electrode separation, 4) motion artifact and 5) deteriorating ground connection and subsequent drop in common mode noise rejection. Single neurons have been observed up to 14 days post implantation and on 40% of micro-wires. Significance Long-term success requires detailed review of each implant by both the clinical and research teams to identify failure modes, and appropriate refinement of techniques while moving forward. This approach leads to reliable unit recordings without prolonging operative times, which will help increase the availability and clinical viability of human single neuron data. PMID:24608589

  6. Comparison of marginal bone loss and patient satisfaction in single and double-implant assisted mandibular overdenture by immediate loading

    PubMed Central

    Khoshhal, Masume; Ebrahimzadeh, Zahra

    2015-01-01

    PURPOSE The purpose of this study was to compare the coronal bone level and patient satisfaction in 1-implant and 2-implant assisted mandibular overdentures. MATERIALS AND METHODS Twenty patients who had maladaptive mandibular dentures were treated in this study. Patients were randomly divided into two groups. The first group received 1 implant (Simple line II, Implantium, South Korea) in their mandibular midline and the second group received 2 implants in their B and D regions (according to Misch's category). If the primary stability of each implant was at least 60 ISQ, ball attachment was placed and denture relined with soft liner. After 6 weeks, retentive cap incorporated with hard acrylic resin. In the 6 and 12 months recalls, periapical digital radiograph were made and visual analogue scale questionnaires were used to record patient satisfaction. The Friedman test was done for comparing the presurgical and postsurgical parameters in each group and the U-Mann Whitney test (P<.05) was done for comparison of post-treatment results between the two groups. RESULTS All implants achieved sufficient primary stability to be immediately loaded. Patient satisfaction was high, and there were no significant differences between two groups (P>.05). In addition, mean marginal bone loss was 0.6 0.67 mm in the first group and 0.6 0.51 mm in the second group, after 12 month. Mean marginal bone loss showed no significant differences between two groups. CONCLUSION This preliminary one-year result indicated that mandibular overdentures anchored to a single implant can be a safe and cost-effective method as a starting step for implant-overdenture treatment. PMID:26140170

  7. Stress Analysis on Single Cobalt/Chrome Prosthesis With a 15-mm Cantilever Placed Over 10/13/15-mm-length Implants: A Simulated Photoelastic Model Study.

    PubMed

    Gastaldo, Jos Fbio Guastelli; Pimentel, Anglica Castro; Gomes, Maria Helena; Sendyk, Wilson Roberto; Lagan, Dalva Cruz

    2015-12-01

    The aim of study was to assess the stress around 10/13/15-mm implants in the mandibular area with a 15-mm cantilevered acrylic-resin-coated prostheses following the application force, using the photoelasticity method. Three photoelastic mandibular models were created containing 10-, 13-, and 15-mm implants in length and 3.75 mm in diameter. The implants had bore internal hex connections and were placed parallel to the intermental region. Abutments with 1-mm high cuffs were placed over the implants, and a single cobalt/chrome metallic prosthesis with a 15-mm cantilever, coated with thermoplastic acrylic resin, was placed on top. Loads of 1.0 and 3.0 bars were applied, and the images were photographed and assessed by photoelasticity method. The greatest stress levels were observed for the 10-mm implants. The stress pattern was the same regardless of implant length; only the magnitude of the stress along the implant body revealed changes. Increased implant length played a role in reducing stress on the investigated area of the model, and the 15-mm implants exhibited the best performance in regard to stress distribution. The highest stress levels were found in the implants closest to the cantilever and the central implant. The longest implants were more favorable in regard to the stress distribution on the peri-implant support structures in the 15-mm cantilevered prosthesis under loads. PMID:24914673

  8. Finite Element Analysis of Bone Stress around Micro-Implants of Different Diameters and Lengths with Application of a Single or Composite Torque Force

    PubMed Central

    Lu, Ying-juan; Chang, Shao-hai; Ye, Jian-tao; Ye, Yu-shan; Yu, Yan-song

    2015-01-01

    Background Stress on the bone surrounding dental micro-implants affects implant success. Purpose To compare the stress on the bone surrounding a micro-implant after application of a single force (SF) of 200 g or a composite force (CF) of 200 g and 6 N.mm torque. Materials and Methods Finite element models were developed for micro-implant diameters of 1.2, 1.6, and 2.0 mm, and lengths of 6, 8, 10, and 12 mm and either a SF or CF was applied. The maximum equivalent stress (Max EQS) of the bone surrounding the micro-implant was determined, and the relationships among type of force, diameter, and length were evaluated. Results The Max EQS of the CF exceeded that of the SF (P< 0.05). The effect of force on stress was related to implant diameter, but not to implant length. The larger CF led to greater instability of the micro-implant and the effect was most pronounced at an implant diameter of 1.2 mm. The use of implant diameters of 1.6 mm and 2.0 mm produced no significant difference in implant stability when either a CF or SF was applied. Conclusion When considering the use of an implant to perform three-dimensional control on the teeth, the implant diameter chosen should be > 1.2 mm. PMID:26659581

  9. Ventricular conduction defects after transcatheter aortic valve implantation: a single-institute analysis.

    PubMed

    Kawaguchi, Akira T; D'Allessandro, Cosimo; Collet, Jean Philippe; Cluzel, Philippe; Makri, Ralouka; Leprince, Pascal

    2015-05-01

    Patients with aortic stenosis tend to develop ventricular conduction problems, which are known adverse events following transcatheter aortic valve implantation (TAVI). Changes in ventricular conduction status after TAVI were analyzed in 195 consecutive patients from a single institute registered in FRANCE2 between February 2010 and June 2012. Among the 195 patients, 29 had a prior pacemaker implantation (+PM) and 6 had acute catastrophic hemodynamics that made a full electrocardiogram (ECG) unavailable. Among the remaining 160, PM was newly required in 28 (17.5%, PM+) but not in 132 (PM-), which included 21 (13.1%) who developed new left bundle branch block (BBB), 12 (7.5%) had right BBB, and 99 (61.9%) had no change. While PM requirement had no correlation with preoperative factors, there was significant association with the development of right BBB with Edwards Sapien/XT (P?=?0.003), and new left BBB (P?=?0.012) and complete heart block requiring PM with CoreValve (22.6% vs. Edwards Sapien/XT, 7.4%, P?=?0.016). Whereas postoperative survival regarding PM status (+PM, PM+, PM-), vascular access, valve size or type showed no difference, delayed heart block (n?=?12, Day 2 or later) was associated with poor survival (P?=?0.038) compared with the remaining PM+ patients with earlier onset (n?=?16, Day 0 or 1). As a result, PM+ patients (n?=?28) had significantly longer intensive care unit (ICU) stay and hospitalization than PM- or +PM patients. The results suggest that ventricular conduction problems requiring PM occurred more frequently after TAVI (17.5%) than with usual surgical replacement. Nonetheless, conduction problems failed to influence postoperative survival for up to 3 years on average with use of PM, but therefore did increase medical costs. PMID:25818075

  10. Strain Doping: Reversible Single-Axis Control of a Complex Oxide Lattice via Helium Implantation.

    PubMed

    Guo, Hangwen; Dong, Shuai; Rack, Philip D; Budai, John D; Beekman, Christianne; Gai, Zheng; Siemons, Wolter; Gonzalez, C M; Timilsina, R; Wong, Anthony T; Herklotz, Andreas; Snijders, Paul C; Dagotto, Elbio; Ward, Thomas Z

    2015-06-26

    We report on the use of helium ion implantation to independently control the out-of-plane lattice constant in epitaxial La(0.7)Sr(0.3)MnO(3) thin films without changing the in-plane lattice constants. The process is reversible by a vacuum anneal. Resistance and magnetization measurements show that even a small increase in the out-of-plane lattice constant of less than 1% can shift the metal-insulator transition and Curie temperatures by more than 100?C. Unlike conventional epitaxy-based strain tuning methods which are constrained not only by the Poisson effect but by the limited set of available substrates, the present study shows that strain can be independently and continuously controlled along a single axis. This permits novel control over orbital populations through Jahn-Teller effects, as shown by Monte Carlo simulations on a double-exchange model. The ability to reversibly control a single lattice parameter substantially broadens the phase space for experimental exploration of predictive models and leads to new possibilities for control over materials' functional properties. PMID:26197138

  11. Blistering and cracking of LiTaO3 single crystal under helium ion implantation

    NASA Astrophysics Data System (ADS)

    Ma, Changdong; Lu, Fei; Ma, Yujie

    2015-03-01

    Blistering and cracking in LiTaO3 surface are investigated after 200-keV helium ion implantation and subsequent post-implantation annealing. Rutherford backscattering/channeling is used to examine the lattice damage caused by ion implantation. Blistering is observed through optical microscopy in a dynamic heating process. Atomic force microscopy and scanning electron microscopy measurements are used to detect the LiTaO3 surface morphology. Experimental results show that blistering and flaking are dependent on implantation fluence, beam current, and also annealing temperature. We speculate that the surface cracking of He+-implanted LiTaO3 results from the implantation-induced stress and compression.

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

    SciTech Connect

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

    2013-12-04

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

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

    SciTech Connect

    Ninomiya, Shiro; Ochi, Akihiro; Kimura, Yasuhiko; Yumiyama, Toshio; Kudo, Tetsuya; Kurose, Takeshi; Kariya, Hiroyuki; Tsukihara, Mitsukuni; Ishikawa, Koji; Ueno, Kazuyoshi

    2011-01-07

    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.

  14. Growth of single-walled carbon nanotubes from hot-implantation-formed catalytic Fe nanoparticles assisted by microwave plasma

    NASA Astrophysics Data System (ADS)

    Hoshino, Yasushi; Arima, Hiroki; Saito, Yasunao; Nakata, Jyoji

    2012-01-01

    We have investigated a fabrication of carbon nanotubes (CNTs) from Fe nano-size clusters formed near the surface of the thermally grown SiO2 layer on the Si substrates using Fe+ implantation at the substrate temperatures of 600 and 1000 °C. In the present study, we have found that the cluster size formed by the 600 °C-implantation is significantly uniform with the mean diameter and standard deviation of 2.6 and 0.6 nm, respectively. In contrast, the diameter distribution for the 1000 °C-implanted sample was slightly deviated, taking the values of 3-13 nm. The cluster size mainly depends on the substrate temperature during the implantation. We have confirmed single-walled CNTs grown from the Fe nanoparticles formed near the surface region in the SiO2 layer, via clearly observed peaks for the radial-breathing-mode in Raman spectra. We have also investigated the growth mechanism of the CNTs in terms of the plasma and surface interactions during microwave-plasma-enhanced chemical vapor deposition (MPCVD). It should be emphasized that the ion implantation technique combined with the MPCVD method is a powerful tool for in situ growth of SWCNT directly on a SiO2 layer or Si substrate.

  15. Attainment of dual-band edge work function by using a single metal gate and single high-k dielectric via ion implantation for HP CMOS device

    NASA Astrophysics Data System (ADS)

    Xu, Qiuxia; Xu, G.; Zhou, H.; Zhu, H.; Liu, J.; Wang, Y.; Li, J.; Xiang, J.; Liang, Q.; Wu, H.; Zhong, J.; Xu, M.; Xu, W.; Ma, X.; Wang, X.; Tong, X.; Chen, D.; Yan, J.; Zhao, C.; Ye, T.

    2016-01-01

    Attainment of dual band-edge effective work functions by using a single metal gate and single high k gate dielectric via P/BF2 implantation into a TiN metal gate for HP HKMG CMOS device applications are investigated under a gate-last process flow for the first time. The flat band voltage (VFB) modulations of about -750 mV/570 mV for N-/P-type MOS device with P/BF2 implanted TiN/HfO2/ILSiO2 gate stack are obtained respectively in the experiment range. Suitable low threshold voltages of CMOSFETs are gotten while simultaneously shrinking the EOT. The effects of P/BF2 ion implantation energy, dose and TiN gate thickness on the properties of implanted TiN/HfO2/ILSiO2 gate stack are studied, the possible mechanisms are discussed. This technique has been successfully integrated into the fabrications of aggressively scaled HP HKMG CMOSFETs and 32 CMOS frequency dividers under a gate-last process flow.

  16. Tooth agenesis: from molecular genetics to molecular dentistry.

    PubMed

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

    2008-07-01

    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 a common solution to tooth loss problems; however, molecular dentistry offers promising solutions for the future. In this paper, the genetic and molecular bases of non-syndromic and syndromic hypodontia are reviewed, and the advantages and disadvantages of tissue engineering in the clinical treatment of tooth agenesis are discussed. PMID:18573979

  17. Tooth formation - delayed or absent

    MedlinePLUS

    Delayed or absent tooth formation; Teeth - delayed or absent formation ... The age at which the tooth comes in varies. Most infants get their first tooth between 6 and 9 months, but it may be earlier or later. ...

  18. Simultaneous Single Dexamethasone Implant and Ranibizumab Injection in a Case with Active Serpiginous Choroiditis and Choroidal Neovascular Membrane

    PubMed Central

    Saatci, Ali Osman; Ayhan, Ziya; Engin Durmaz, Ceren; Takes, Omer

    2015-01-01

    Intravitreal anti-vascular endothelial growth factor (VEGF) agents seem to be effective in choroidal neovascular membranes (CNV) in association with various entities of posterior uveitis. We herein report a 46-year-old woman who was treated with a simultaneous single intravitreal dexamethasone implant and ranibizumab administration for the treatment of unilateral extrafoveal CNV associated with an active serpiginous choroiditis. Simultaneously with the intravitreal therapy, oral mycophenolic acid (2 720 mg) was started, and oral cyclosporine (3 100 mg) was then added 2 months later. On the other hand, the fellow eye had been treated for subfoveal CNV but with an inactive disease 4 years previously and ended up with a final visual acuity of counting fingers despite treatment with a single session of photodynamic therapy and 3 subsequent intravitreal ranibizumab injections. Simultaneous administration of anti-VEGF agents and a dexamethasone implant can be a viable approach in eyes with CNV and active serpiginous choroiditis.

  19. Formation of single crystalline tellurium supersaturated silicon pn junctions by ion implantation followed by pulsed laser melting

    NASA Astrophysics Data System (ADS)

    Xiyuan, Wang; Yongguang, Huang; Dewei, Liu; Xiaoning, Zhu; Xiao, Cui; Hongliang, Zhu

    2013-06-01

    Pn junctions based on single crystalline tellurium supersaturated silicon were formed by ion implantation followed by pulsed laser melting (PLM). P type silicon wafers were implanted with 245 keV 126Te+ to a dose of 2 × 1015 ions/cm2, after a PLM process (248 nm, laser fluence of 0.30 and 0.35 J/cm2, 1-5 pulses, duration 30 ns), an n+ type single crystalline tellurium supersaturated silicon layer with high carrier density (highest concentration 4.10 × 1019 cm-3, three orders of magnitude larger than the solid solution limit) was formed, it shows high broadband optical absorption from 400 to 2500 nm. Current—voltage measurements were performed on these diodes under dark and one standard sun (AM 1.5), and good rectification characteristics were observed. For present results, the samples with 4-5 pulses PLM are best.

  20. A comparison of the magnetic properties of radiation damaged or Co implanted ZnO single crystals

    NASA Astrophysics Data System (ADS)

    Werner, Z.; Gosk, J.; Twardowski, A.; Barlak, M.; Pochrybniak, C.

    2015-09-01

    To elucidate the interaction between defects and transition metal impurities in creating magnetic properties in wide band-gap semiconductors, single crystals of ZnO were irradiated with high-energy electrons, protons and Co ions. Magnetization of samples was measured before and after room temperature irradiation. The measurements reveal that only Co implantation creates measurable magnetization, which is related to the simultaneous introduction of defects. Consequences of the experimental results are discussed.

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

    SciTech Connect

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

    2005-04-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2005-04-01

    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.

  3. Two cross-linked porcine dermal implants in a single patient undergoing hernia repair

    PubMed Central

    Linz, Luke A; Burke, Leandra H; Miller, Lisa A

    2013-01-01

    A 50-year-old woman with a history of multiple recurrent incisional hernias and multiple comorbidities received two different porcine dermal implants during the same procedure due to the availability of products in stock. At 3.5?months following this procedure, the patient developed a secondary hernia inferior and lateral to the site of previous surgery. Both the implants were biopsied and sent for pathological evaluation. One implant was compliant and well integrated while the other was non-compliant and exhibited extensive foreign body reaction. In this case report, we examine the differences between the two porcine implants that may have caused them to react so differently in the same subject under the same conditions. PMID:23345480

  4. Cochlear implantation in children with single-sided deafness: does aetiology and duration of deafness matter?

    PubMed

    Arndt, Susan; Prosse, Susanne; Laszig, Roland; Wesarg, Thomas; Aschendorff, Antje; Hassepass, Frederike

    2015-01-01

    For adult patients with single-sided deafness (SSD), treatment with a cochlear implant (CI) is well established as an acceptable and beneficial hearing rehabilitation method administered routinely in clinical practice. In contrast, for children with SSD, CI has been applied less often to date, with the rationale to decide either on a case-by-case basis or under the realm of clinical research. The aim of our clinical study was to evaluate the longitudinal benefits of CI for a group of children diagnosed with SSD and to compare their outcomes with respect to patient characteristics. Evaluating a pool of paediatric SSD patients presenting for possible CI surgery revealed that the primary aetiology of deafness was congenital cochlear nerve deficiency. A subgroup of children meeting the CI candidacy criteria for the affected ear (the majority with acquired hearing loss) were enrolled in the study. Preliminary group results suggest substantial improvements in speech comprehension in noise and in the ability to localise sound, which was demonstrated through objective and subjective assessments after CI treatment for the group, with results varying from patient to patient. Our study shows a trend towards superior outcomes for children with acquired hearing loss and a shorter duration of hearing loss compared to congenitally deafened children who had a longer duration of SSD. This indicates an interactive influence of the age at onset, aetiology and duration of deafness upon the restoration of binaural integration and the overall benefits of sound stimulation to two ears after CI treatment. Continued longitudinal investigation of these children and further studies in larger groups may provide more guidance on the optimal timing of treatment for paediatric patients with acquired and congenital SSD. PMID:25999052

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

    PubMed

    Ray, M P; Baldwin, J W; Feygelson, T I; Butler, J E; Pate, B B

    2011-05-01

    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. PMID:21639553

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

    SciTech Connect

    Ray, M. P.; Baldwin, J. W.; Butler, J. E.; Pate, B. B.; Feygelson, T. I.

    2011-05-15

    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.

  7. Orthodontic tooth movement after different coxib therapies.

    PubMed

    de Carlos, Felix; Cobo, Juan; Perillan, Carmen; Garcia, Miguel A; Arguelles, Juan; Vijande, Manuel; Costales, Marina

    2007-12-01

    Anti-inflammatory substances used for treatment of pain and discomfort related to orthodontic treatment (OT) could slow down tooth movement. Selective cyclooxygenase-2 inhibitors are an alternative to conventional non-steroidal anti-inflammatory drugs. The aim of this study was to compare different coxibs on dental movement in the rat. Twenty-eight Wistar male rats (3 months old) divided into four experimental groups were studied: (1) Five rats underwent a 50 g coil spring implantation and received three injections of 0.5 mg/kg body weight (bw) of Rofecoxib in the maxillary gingiva, close to the first molar, on the day of implantation and after 3 and 5 days. Similar procedures were carried out (2) on six animals receiving 8 mg/kg bw of Celecoxib and (3) on five animals receiving 25 mg/kg bw of Parecoxib. (4) For the controls, 12 rats received the same OT but only equivolumetric 0.9 per cent saline solution injections. Tooth movement was measured on lateral cranial teleradiographs after 10 days of treatment. Non-parametric standard techniques (Wilcoxon, H, and Mann-Whitney, U) were used for statistical analysis. Mesial tooth displacement in the control animals was 0.33 +/- 0.07 mm. While no movement was found in rats treated with Rofecoxib, the Celecoxib- and Parecoxib-treated rats showed tooth movement of 0.42 +/- 0.09 mm and 0.22 +/- 0.04 mm, respectively. The differences were statistically significant (H = 13.07; P < 0.004). Celecoxib and Parecoxib, but not Rofecoxib, seem appropriate for discomfort and pain relief while avoiding interference during tooth movement. PMID:17878187

  8. A new approach for deciphering between single and multiple accumulation events using intra-tooth isotopic variations: Application to the Middle Pleistocene bone bed of Schningen 13 II-4.

    PubMed

    Julien, Marie-Anne; Rivals, Florent; Serangeli, Jordi; Bocherens, Herv; Conard, Nicholas J

    2015-12-01

    It is often difficult to differentiate between archaeological bonebeds formed by one event such as a mass kill of a single herd, and those formed by multiple events that occurred over a longer period of time. The application of high temporal resolution studies such as intra-tooth isotopic profiles on archaeological mammal cohorts offers new possibilities for exploring this issue, allowing investigators to decipher between single and multiple accumulation events. We examined (18)O and (13)C isotopic variations from the enamel carbonate of 23 horse third molars from the Middle Pleistocene archaeological site of Schningen. We employed a new approach to investigate processes of fossil accumulation that uses both bulk and intra-tooth isotopic variations and takes into account animal behavior, age at death and dental development to test the degree of isotopic affinity of animals from the same fossil assemblage. Oxygen and carbon isotope bulk values indicate that the horses from Schningen 13 II-4 experienced relatively similar climatic and dietary regimes. Inter-individual differences of the bulk values of the horses sampled in the current study present nevertheless inter-individual variability similar to individuals from multi-layered localities. In addition, the intra-tooth isotopic variation of specimens of the same age at death seems to indicate that the studied cohort corresponds to a mix of individuals that recorded both similar and different isotopic histories. Finally, the conditions recorded in the isotopic signal shortly before death (i.e., for teeth not fully mineralized) varied between sampled individuals, suggesting possible differences in the seasonality of death. Considering those results, we discuss the possibility that the horses from Schningen 13 II-4 correspond to an accumulation of different death events. PMID:25912820

  9. Simplified type 3 implant placement, after alveolar ridge preservation: a case study

    PubMed Central

    CECCHETTI, F.; GERMANO, F.; BARTULI, F.N.; ARCURI, L.; SPUNTARELLI, M.

    2014-01-01

    Alveolar ridge, after tooth extraction, could reduce its volume up to 50% in buccal-lingual width in the first twelve months and residual dimensions could interfere with correct three dimensional placement of implants and influence negatively treatment outcomes with regard to function and aesthetic aspects. Over the last decades, several approaches have been proposed and tested in order to prevent ridge volumetric contraction and provide maximum bone availability for implant procedure. This article presents a case study with a single anterior tooth replacement, illustrating socket seal technique followed by a type 3 timing implant placement. Immediately after tooth extraction, residual socket was grafted using Deproteinized Bovine Bone Mineral and a free gingival punch harvested from palate. After 3 months, a root-form titanium implant was inserted without additional regenerative procedures. Follow-up examination revealed favourable preservation of soft tissue width and height in the aesthetic area. Socket seal approach maximizes soft tissue healing, preserving ridge envelope and the subsequent implant placement, furthermore, results simplified, as any augmentation techniques are required. Clinical advantages of this method include predictable preservation of the soft tissues, favourable healing features, easy handling of graft materials and a positive benefit-cost ratio. PMID:25992262

  10. Single-Dose Local Simvastatin Injection Improves Implant Fixation via Increased Angiogenesis and Bone Formation in an Ovariectomized Rat Model

    PubMed Central

    Tan, Jie; Yang, Ning; Fu, Xin; Cui, Yueyi; Guo, Qi; Ma, Teng; Yin, Xiaoxue; Leng, Huijie; Song, Chunli

    2015-01-01

    Background Statins have been reported to promote bone formation. However, taken orally, their bioavailability is low to the bones. Implant therapies require a local repair response, topical application of osteoinductive agents, or biomaterials that promote implant fixation. Material/Methods The present study evaluated the effect of a single local injection of simvastatin on screw fixation in an ovariectomized rat model of osteoporosis. Results Dual-energy X-ray absorptiometry, micro-computed tomography, histology, and biomechanical tests revealed that 5 and 10 mg simvastatin significantly improved bone mineral density by 18.2% and 22.4%, respectively (P<0.05); increased bone volume fraction by 51.0% and 57.9%, trabecular thickness by 16.4% and 18.9%, trabeculae number by 112.0% and 107.1%, and percentage of osseointegration by 115.7% and 126.3%; and decreased trabeculae separation by 34.1% and 36.6%, respectively (all P<0.01). Bone mineral apposition rate was significantly increased (P<0.01). Furthermore, implant fixation was significantly increased (P<0.05), and bone morphogenetic protein 2 (BMP2) expression was markedly increased. Local injection of a single dose of simvastatin also promoted angiogenesis. Vessel number, volume, thickness, surface area, and vascular volume per tissue volume were significantly increased (all P<0.01). Vascular endothelial growth factor (VEGF), VEGF receptor-2, von Willebrand factor, and platelet endothelial cell adhesion molecule-1 expression were enhanced. Conclusions A single local injection of simvastatin significantly increased bone formation, promoted osseointegration, and enhanced implant fixation in ovariectomized rats. The underlying mechanism appears to involve enhanced BMP2 expression and angiogenesis in the target bone. PMID:25982481

  11. Measuring dental drift and orthodontic tooth movement in response to various initial forces in adult rats.

    PubMed

    King, G J; Keeling, S D; McCoy, E A; Ward, T H

    1991-05-01

    A method for the quantification of orthodontic tooth movement in the rat is presented. Reliability, sensitivity, and validity were assessed and tooth movement kinetics were determined for initial forces of 20, 40, and 60 gm. The appliance consisted of a 9 mm length of closed coil spring suspended between a cleat and bonded to the occlusal surface of the maxillary first molars and the maxillary incisors. Initial tipping forces were placed by suspending known weights from the anterior end of these coils before fixation to the incisors. Tooth movement was quantified from enlarged cephalograms by measuring the position of a reproducible landmark on the molar cleat with respect to either zygomatic amalgam implants or a barbed broach placed submucosally on the palate. All measurements were made along the molar-incisor vector by projecting at 90 degrees to this line. Validity and sensitivity were assessed by quantifying molar distal drift and comparing these results with reports of bone turnover rates adjacent to distally drifting adult rat molars. Reliability was obtained by estimating the error of a single measurement in a longitudinal study of 12 adult male Sprague-Dawley rats (180 to 200 days) receiving both amalgam and broach implants and a cross-sectional study of 72 animals divided equally into six groups to be killed at 1, 3, 5, 7, 10, and 14 days. No orthodontic forces were used in this portion of the study. Implant stability within the craniofacial complex was assessed by measuring bilateral broaches as a function of time with respect to each other. There were no systematic errors between replicate films for either the amalgam or the broach method. The 95% confidence limit for a single determination of molar position was 62 microns using the amalgams and 47 microns for the broach (p less than 0.001). The latter could be reduced to 23 microns when the average of four independent determinations was used. Homologous implants did not differ with respect to each other in the sagittal plane but did in the transverse plane (p less than 0.01), migrating laterally 9 microns/day. Linear regression analysis of molar distal movement over time predicted 7.7 microns/day distal drift (p less than 0.01), which compared favorably with reports of 6.7 microns/day of alveolar bone turnover during this drifting process. Characteristic three-part cumulative tooth movement kinetics were obtained for the 40 and 60 gm initial force groups. No individual time point at 60 gm differed from its counterpart at 40 gm.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2028935

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

    NASA Astrophysics Data System (ADS)

    Corra, Cssia B.; Ramos, Nuno V.; Monteiro, Jaime; Vaz, Luis G.; Vaz, Mario A. P.

    2012-10-01

    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.

  13. Dental Caries (Tooth Decay)

    MedlinePLUS

    ... Search Text size: Website Contents NIDCR Home Oral Health Diseases and Conditions Gum Disease TMJ Disorders Oral Cancer Dry Mouth Burning Mouth Tooth Decay See All Oral Complications of Systemic Diseases Cancer Treatment Developmental Disabilities Diabetes Heart Disease ...

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

    PubMed

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

    2011-10-01

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

  15. A single-chip signal processing and telemetry engine for an implantable 96-channel neural data acquisition system

    NASA Astrophysics Data System (ADS)

    Rizk, Michael; Obeid, Iyad; Callender, Stephen H.; Wolf, Patrick D.

    2007-09-01

    A fully implantable neural data acquisition system is a key component of a clinically viable cortical brain-machine interface. We present the design and implementation of a single-chip device that serves the processing needs of such a system. Our device processes 96 channels of multi-unit neural data and performs all digital processing necessary for bidirectional wireless communication. The implementation utilizes a single programmable logic device that is responsible for performing data reduction on the 96 channels of neural data, providing a bidirectional telemetry interface to a transceiver and performing command interpretation and system supervision. The device takes as input neural data sampled at 31.25 kHz and outputs a line-encoded serial bitstream containing the information to be transmitted by the transceiver. Data can be output in one of the following four modes: (1) streaming uncompressed data from a single channel, (2) extracted spike waveforms from any subset of the 96 channels, (3) 1 ms bincounts for each channel or (4) streaming data along with extracted spikes from a single channel. The device can output up to 2000 extracted spikes per second with latencies suitable for a brain-machine interface application. This device provides all of the digital processing components required by a fully implantable system.

  16. A photoluminescence study of CuInSe2 single crystals ion implanted with 5 keV hydrogen

    NASA Astrophysics Data System (ADS)

    Yakushev, M. V.; Krustok, J.; Grossberg, M.; Volkov, V. A.; Mudryi, A. V.; Martin, R. W.

    2016-03-01

    CuInSe2 single crystals ion implanted with 5 keV hydrogen at doses from 3  ×  1014 to 1016 cm‑2 are studied by photoluminescence (PL). The PL spectra before and after implantation reveal two bands, a main dominant band centred at 0.96 eV and a lower intensity band centred at 0.93 eV. Detailed analysis of the shape of these bands, their temperature and excitation intensity dependencies allow the recombination mechanisms to be identified as band-to-tail (BT) and band-to-impurity (BI), respectively. The implantation causes gradual red shifts of the bands increasing linearly with the dose. The average depth of potential fluctuations is also estimated to increase with the dose and saturates for doses above 1015 cm‑2. A model is proposed which associates the potential fluctuations with the antisite defects copper on indium site and indium on copper site. The saturation is explained by full randomization of copper and indium atoms on the cation sub-lattice.

  17. Single-Stage Anterior Debridement and Fibular Allograft Implantation Followed by Posterior Instrumentation for Complicated Infectious Spondylitis

    PubMed Central

    Chung, Tzu-Chun; Yang, Shih-Chieh; Chen, Hung-Shu; Kao, Yu-Hsien; Tu, Yuan-Kun; Chen, Wen-Jer

    2014-01-01

    Abstract Complicated infectious spondylitis is an infrequent infection with severe spinal destruction, and is indicated for combined anterior and posterior surgeries. Staged debridement and subsequent reconstruction is advocated in the literature. The purpose of this study is to evaluate the feasibility and clinical outcome of patients who underwent single-stage combined anterior debridement and fibular allograft implantation followed by supplemental posterior fixation for complicated infectious spondylitis. We retrospectively reviewed the medical records of 20 patients who underwent single-stage combined anterior and posterior surgeries for complicated infectious spondylitis from January 2005 to December 2010. Complicated infectious spondylitis was defined as at least 1 vertebral osteomyelitis with pathological fracture or severe bony destruction and adjacent discitis, based on imaging studies. The severity of the neurological status was evaluated using the Frankel scale. The clinical outcomes were assessed by careful physical examination and regular serological tests to determine the visual analog scale (VAS) score and Macnab criteria. Correction of the sagittal Cobb angle on radiography was also compared before and after surgery. The Wilcoxon signed-rank test was used to analyze patient surgical prognosis and radiological findings. All patients with complicated infectious spondylitis were successfully treated by single-stage combined anterior and posterior surgeries. No patients experienced neurologic deterioration. The average VAS score was 7.8 before surgery and significantly decreased to 2.1 at discharge. Three patients had excellent outcomes and 17 had good outcomes, based on Macnab criteria. The average length of the allograft for reconstruction was 64.0 mm. Kyphotic deformity improved in all patients, with an average correction angle of 13.4. There was no implant breakage or allograft dislodgement during at least 36 months of follow-up. Single-stage anterior debridement and fibular allograft implantation followed by posterior pedicle screw instrumentation provide immediate stability, satisfactory alignment, and successful infection control. Fibular allograft implantation seems to be a good alternative for anterior reconstruction; it can proceed to bony incorporation and avoids donor site morbidity. PMID:25501067

  18. Successful Transplantation of Kidneys From Elderly Circulatory Death Donors by Using Microscopic and Macroscopic Characteristics to Guide Single or Dual Implantation.

    PubMed

    Mallon, D H; Riddiough, G E; Summers, D M; Butler, A J; Callaghan, C J; Bradbury, L L; Bardsley, V; Broecker, V; Saeb-Parsy, K; Torpey, N; Bradley, J A; Pettigrew, G J

    2015-11-01

    Most kidneys from potential elderly circulatory death (DCD) donors are declined. We report single center outcomes for kidneys transplanted from DCD donors over 70 years old, using preimplantation biopsy Remuzzi grading to inform implantation as single or dual transplants. Between 2009 and 2012, 43 single transplants and 12 dual transplants were performed from elderly DCD donors. Remuzzi scores were higher for dual than single implants (4.4 vs. 3.4, p?singly implanted kidneys, and in one dual-implanted kidney; its pair continued to function satisfactorily. Death-censored graft survival at 3 years was comparable for the two groups (single 94%; dual 100%), as was 1 year eGFR. Delayed graft function occurred less frequently in the dual-implant group (25% vs. 65%, p?=?0.010). Using this approach, we performed proportionally more kidney transplants from elderly DCD donors (23.4%) than the rest of the United Kingdom (7.3%, p?

  19. Implant and root supported overdentures - a literature review and some data on bone loss in edentulous jaws

    PubMed Central

    2014-01-01

    PURPOSE To present a literature review on implant overdentures after a brief survey of bone loss after extraction of all teeth. MATERIALS AND METHODS Papers on alveolar bone loss and implant overdentures have been studied for a narrative review. RESULTS Bone loss of the alveolar process after tooth extraction occurs with great individual variation, impossible to predict at the time of extraction. The simplest way to prevent bone loss is to avoid extraction of all teeth. To keep a few teeth and use them or their roots for a tooth or root-supported overdenture substantially reduces bone loss. Jaws with implant-supported prostheses show less bone loss than jaws with conventional dentures. Mandibular 2-implant overdentures provide patients with better outcomes than do conventional dentures, regarding satisfaction, chewing ability and oral-health-related quality of life. There is no strong evidence for the superiority of one overdenture retention-system over the others regarding patient satisfaction, survival, peri-implant bone loss and relevant clinical factors. Mandibular single midline implant overdentures have shown promising results but long-term results are not yet available. For a maxillary overdenture 4 to 6 implants splinted with a bar provide high survival both for implants and overdenture. CONCLUSION In edentulous mandibles, 2-implant overdentures provide excellent long-term success and survival, including patient satisfaction and improved oral functions. To further reduce the costs a single midline implant overdenture can be a promising option. In the maxilla, overdentures supported on 4 to 6 implants splinted with a bar have demonstrated good functional results. PMID:25177466

  20. Acoustic tooth cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S. (Inventor)

    1982-01-01

    An acoustic oral hygiene unit is described that uses acoustic energy to oscillate mild abrasive particles in a water suspension which is then directed in a low pressure stream onto the teeth. The oscillating abrasives scrub the teeth clean removing food particles, plaque, calculous, and other foreign material from tooth surfaces, interproximal areas, and tooth-gingiva interface more effectively than any previous technique. The relatively low power output and the basic design makes the invention safe and convenient for everyday use in the home without special training. This invention replaces all former means of home dental prophylaxis, and requires no augmentation to fulfill all requirements for daily oral hygienic care.

  1. Connecting teeth to implants: a critical review of the literature and presentation of practical guidelines.

    PubMed

    Greenstein, Gary; Cavallaro, John; Smith, Richard; Tarnow, Dennis

    2009-09-01

    Historically, connecting a tooth to an implant to function as an abutment to replace a missing tooth was discouraged. It was believed differences in mobility patterns of a tooth and an implant would result in the prosthesis being cantilevered off the implant, thereby stressing the implant. Several papers concluded increased stress caused technical and biologic complications, which led to a decreased survival rate for a tooth-implant supported prosthesis (TISP) when compared with an implant-only supported prosthesis (ISP). However, problems attributed to TISPs may have been overstated. This paper reviews animal studies and human clinical trials that monitored successful use of TISPs. In addition, numerous issues are addressed that question the data, which have been interpreted to indicate that a tooth should not be connected to an implant. Recommendations are made to facilitate attaining high success rates with TISPs. PMID:19757737

  2. Current trends in dental implants

    PubMed Central

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

    2014-01-01

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

  3. Clinical and Radiographic Evaluation of Brnemark Implants with an Anodized Surface following Seven-to-Eight Years of Functional Loading

    PubMed Central

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

    2013-01-01

    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. PMID:23533412

  4. Pneumomediastinum after Tooth Extraction

    PubMed Central

    Ocakcioglu, Ilhan; Koyuncu, Serhat; Kupeli, Mustafa; Bol, Oguzhan

    2016-01-01

    Pneumomediastinum is defined as the presence of air in mediastinum. Pneumomediastinum can sometimes occur after surgery. Pneumomediastinum seen after dental procedures is rare. We presented the case of subcutaneous emphysema developed in the neck and upper chest after tooth extraction and discussed the possible mechanisms of pneumomediastinum.

  5. I Lost My Tooth!

    ERIC Educational Resources Information Center

    Boehm, Diann

    1997-01-01

    Highlights the Internet Schoolhouse Web site and outlines a cross-curriculum (language arts, geography, social studies, health, art, and math) lesson plan for a grades K-3 telecommunications project in which students gather data about lost teeth and share tooth-fairy legends. Lists required hardware, software, and other materials and describes

  6. The Rachitic Tooth

    PubMed Central

    Nociti, Francisco H.; Somerman, Martha J.

    2014-01-01

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

  7. Patients awareness and attitude towards dental implants

    PubMed Central

    Kohli, Shivani; Bhatia, Shekhar; Kaur, Arvinder; Rathakrishnan, Tiviya

    2015-01-01

    Aims: The aim of the study was to assess the awareness of the patients regarding implant-retained prosthesis as an option for tooth replacement and the knowledge about tooth replacement as a whole including source of information and attitude towards it amongst Malaysian population. Materials and Methods: Information on demographic characteristics, knowledge about implant as an option for missing tooth replacement, source of information and knowledge about other options of tooth replacement were obtained from patients visiting various dental outpatient departments of hospital and private dental clinics using nationwide self-explanatory survey. Results: Amongst the 1013 response retrieved, 27% of respondents felt moderately well informed about the dental implant treatment. Only 9% of the respondents had dental implant treatment before and 17% felt well informed about different alternatives of replacing missing teeth. The dentists were the main source of information regarding dental implant treatment modality followed by friends and electronic media. 55.6% respondents felt implant to be as good as own teeth during function whereas high cost was the major limiting factor for implant treatment. Conclusion: 56% of Malaysian population was aware of dental implant as an alternative for replacing missing teeth. Necessary efforts and measures should be made to raise the awareness of dental implant treatment in the country. PMID:26752875

  8. Endogenous folates and single-carbon metabolism in the ovarian follicle, oocyte and pre-implantation embryo.

    PubMed

    Kwong, W Y; Adamiak, S J; Gwynn, A; Singh, R; Sinclair, K D

    2010-04-01

    Maternal B-vitamin status at conception can affect fertility and the health of offspring. This study details transcript expression for genes encoding key enzymes in the linked methionine/folate cycles in the bovine oocyte, somatic cells of the ovarian follicle and pre-implantation embryo. Transcripts for all 12 enzymes that were studied and for the two folate receptors (FOLR1 and FOLR2) and reduced folate carrier (SLC19A1) were expressed in liver cells, but transcripts for betaine-homocysteine methyltransferase and methionine adenosyl transferase 1A were absent in all ovarian cells, and transcripts for FOLR2 were absent in embryonic cells. Transcripts for glycine methyltransferase were also absent/weak in cumulus and granulosa cells. The absence of these enzymes could have a profound effect on single-carbon metabolism within the ovary and pre-implantation embryo. Immunocytochemical analysis revealed SLC19A1 protein expression on the plasma and basal-lateral membranes of the pre-implantation embryo. The folate antagonist methotrexate (MTX) enters the cell via SLC19A1, and in the current study, MTX inclusion in bovine/ovine culture media at either 1 or 10 microM from the 1-cell stage inhibited embryo development beyond the 8-cell stage. Hypoxanthine and thymidine (100 microM) increased the proportion of embryos that developed to blastocysts, but the cell number was reduced by 20%. The reduced uptake of [(35)S] methionine into intra-cellular S-adenosylmethionine and S-adenosylhomocysteine pools, together with reduced uptake of glutamate and tryptophan, was consistent with depleted intra-cellular pools of reduced folates. These data provide an insight into the importance of maternal dietary folate/B-vitamin status during the peri-conceptional period. PMID:20083604

  9. The study of structural properties of 100 keV hydrogen ion implanted semi-insulating GaAs single crystals

    NASA Astrophysics Data System (ADS)

    Udhayasankar, M.; Kumar, J.; Ramasamy, P.; Sekar, K.; Sundaravel, B.; Ferrari, C.; Lazzarini, L.; Magudapathy, P.; Nair, K. G. M.

    1999-03-01

    100 keV hydrogen ion implantation has been carried out on undoped semi-insulating <1 0 0> gallium arsenide single crystals for various ion doses at room temperature. The structural properties due to high dose, low energy hydrogen ion implantation has been investigated using X-ray double crystal diffractometry (DCD) analysis, Rutherford backscattering spectrometry and channeling (RBS/C) experiments and transmission electron microscopy (TEM) analysis. By using DCD analysis, the value of elastic lattice strain for the ion doses of 1 10 16, 1 10 18 ions/cm 2 has been estimated to be 2.1 10 -3 and 3.2 10 -3, respectively. The RBS spectra in the channeling mode for the high dose implantations (10 17 and 10 18 ions/cm 2) show a high yield indicating a highly damaged region near the range of the implanted hydrogen ions. Particularly, for the dose 10 18 ions/cm 2, a heavily damaged region at the surface can be observed. The TEM results evidenced that no amorphisation occurred for the dose 10 18 ions/cm 2. From TEM characterisation, it is also observed that there are no hydrogen bubbles present in the implanted region. But small dislocation loops have been identified. The projected range of implanted hydrogen ions and the thickness of the implanted layer obtained by RBS and TEM analysis are compared with the TRIM calculations.

  10. Comparison of single-standing or connected implants on stress distribution in bone of mandibular overdentures: a two-dimensional finite element analysis.

    PubMed

    Tabata, Lucas Fernando; Assuno, Wirley Gonalves; Baro, Valentim Adelino Ricardo; Gomes, Erica Alves; Delben, Juliana Aparecida; de Sousa, Edson Antnio Capello; Rocha, Eduardo Passos

    2010-05-01

    This study aimed to compare the influence of single-standing or connected implants on stress distribution in bone of mandibular overdentures by means of two-dimensional finite element analysis. Two finite element models were designed using software (ANSYS) for 2 situations: bar-clip (BC) group-model of an edentulous mandible supporting an overdenture over 2 connected implants with BC system, and o'ring (OR) group-model of an edentulous mandible supporting an overdenture over 2 single-standing implants with OR abutments. Axial loads (100 N) were applied on either central (L1) or lateral (L2) regions of the models. Stress distribution was concentrated mostly in the cortical bone surrounding the implants. When comparing the groups, BC (L1, 52.0 MPa and L2, 74.2 MPa) showed lower first principal stress values on supporting tissue than OR (L1, 78.4 MPa and L2, 76.7 MPa). Connected implants with BC attachment were more favorable on stress distribution over peri-implant-supporting tissue for both loading conditions. PMID:20485031

  11. Dynamic transcriptional symmetry-breaking in pre-implantation mammalian embryo development revealed by single-cell RNA-seq.

    PubMed

    Shi, Junchao; Chen, Qi; Li, Xin; Zheng, Xiudeng; Zhang, Ying; Qiao, Jie; Tang, Fuchou; Tao, Yi; Zhou, Qi; Duan, Enkui

    2015-10-15

    During mammalian pre-implantation embryo development, when the first asymmetry emerges and how it develops to direct distinct cell fates remain longstanding questions. Here, by analyzing single-blastomere transcriptome data from mouse and human pre-implantation embryos, we revealed that the initial blastomere-to-blastomere biases emerge as early as the first embryonic cleavage division, following a binomial distribution pattern. The subsequent zygotic transcriptional activation further elevated overall blastomere-to-blastomere biases during the two- to 16-cell embryo stages. The trends of transcriptional asymmetry fell into two distinct patterns: for some genes, the extent of asymmetry was minimized between blastomeres (monostable pattern), whereas other genes, including those known to be lineage specifiers, showed ever-increasing asymmetry between blastomeres (bistable pattern), supposedly controlled by negative or positive feedbacks. Moreover, our analysis supports a scenario in which opposing lineage specifiers within an early blastomere constantly compete with each other based on their relative ratio, forming an inclined 'lineage strength' that pushes the blastomere onto a predisposed, yet flexible, lineage track before morphological distinction. PMID:26395495

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

    PubMed Central

    Nim?enko, Tatjana; Omerca, Gravydas; Varinauskas, Vaidas; Bramanti, Ennio; Signorino, Fabrizio; Cicci, Marco

    2013-01-01

    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. PMID:23878556

  13. Three-unit bridge construction in anterior single-pontic areas using a metal-free restorative.

    PubMed

    Narcisi, E M

    1999-02-01

    A new glass-ceramic material, IPS Empress 2, is revolutionizing esthetic restorative dentistry by allowing metal-free, three-unit bridge construction in anterior and premolar single-pontic areas. The case discussed in this article illustrates the material's application in the dual-arch restoration of a young woman with congenitally missing teeth. The material was used as an alternative to single-tooth implant restorations to place two maxillary three-unit bridges, one mandibular three-unit bridge, and two mandibular porcelain veneers. IPS Empress 2 provides an esthetic alternative to porcelain-fused-to-metal restorations by facilitating attractive, functional tooth restoration. PMID:11692325

  14. LETTER TO THE EDITOR: High Curie-temperature ferromagnetism in cobalt-implanted single-crystalline rutile

    NASA Astrophysics Data System (ADS)

    Khaibullin, R. I.; Tagirov, L. R.; Rameev, B. Z.; Ibragimov, Sh Z.; Yildiz, F.; Aktas, B.

    2004-10-01

    The ion implantation technique has been used to fabricate a Co-rich layer in rutile: single-crystalline TiO2 substrates were heavily irradiated by Co+ ions with energy of 40 keV. The magnetic properties of as-prepared and post-annealed samples were studied by both inductive and Faraday magnetometry as well as ferromagnetic resonance (FMR). A ferromagnetic Curie temperature as high as 700 K was measured in our samples. The analysis of the magnetic hysteresis loop, the temperature dependence of the saturation magnetization, and strong out-of-plane anisotropy of the FMR spectra allow us to suppose that the origin of the macroscopic high-temperature ferromagnetism is the exchange interaction mediated by oxygen vacancies.

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

    PubMed Central

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

    2014-01-01

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

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

    SciTech Connect

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

    2010-11-15

    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.

  17. Gear tooth topological modification

    NASA Technical Reports Server (NTRS)

    Kish, Jules G. (Inventor); Isabelle, Charles (Inventor)

    1994-01-01

    The topology of parallel axis gears, such as spur and helical gears is modified to produce quieter and more smoothly operating gear sets with more uniform load distribution. A finite element analysis of the gear in its operating mode is made to produce a plot of radial and tangential deflections of the pinion and gear tooth surfaces which will occur when the gears are loaded during operation. The resultant plot is then inverted to produce a plot, or set of coordinates, which will define the path of travel of the gear tooth grinding wheel, which path is a mirror image of the plot of the finite element analysis. The resulting gears, when subjected to operating loads, will thus be deflected tangentially and radially to their optimum operating, or theoretical true involute, positions so as to produce quieter, smoother, and more evenly loaded gear trains.

  18. Three tooth kinematic coupling

    DOEpatents

    Hale, Layton C. (Livermore, CA)

    2000-01-01

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

  19. Tooth whitening in children.

    PubMed

    Donly, Kevin J; Donly, Adriana Segura; Baharloo, Laila; Rojas-Candelas, Edith; Garcia-Godoy, Franklin; Zhou, Xiaojie; Gerlach, Robert W

    2002-01-01

    Although there are several case reports of vital tooth bleaching in children, there is limited clinical trial evidence of the safety or efficacy of this practice. Accordingly, a new clinical trial was conducted to evaluate the effects of 2 different bleaching systems, a 6.5% hydrogen peroxide strip system and a 10% carbamide peroxide tray system, in a population of preteens and teens. A total of 106 volunteers, aged 11 to 18 years, took part in this 8-week study. Patients were randomized by a ratio of 2:1 to the strip or tray groups, with each group treating the maxillary arch first and then the mandibular arch for 4 consecutive weeks each. Individuals assigned to the strip group used the system twice daily for 30 minutes (a total of 56 contact hours over the 8-week study). Those assigned to the tray group used that system overnight (approximately 448 contact hours). Digital images were obtained at baseline and after every 2-week treatment period. Average tooth color was determined in L*, a*, b* color space, where L* indicated lightness, a* indicated red-green, and b* indicated yellow-blue. Both systems significantly whitened teeth (P < 0.0001). While there were no significant differences between groups with respect to the primary whitening response (delta b*) on the maxillary teeth, 4 weeks of overnight treatment with the 10% carbamide peroxide tray (approximately 224 contact hours) yielded statistically significant whitening (P < 0.05) on the mandibular teeth compared with the 6.5% hydrogen peroxide strip used for 28 hours. Both tooth-whitening systems had similar sensitivity/irritation reported after instructed use. This research demonstrates that tooth whitening in teens may be safely accomplished using either the short-contact-time hydrogen peroxide bleaching strips or the overnight carbamide peroxide tray systems tested in this study. PMID:11913290

  20. Implants as absolute anchorage.

    PubMed

    Rungcharassaeng, Kitichai; Kan, Joseph Y K; Caruso, Joseph M

    2005-11-01

    Anchorage control is essential for successful orthodontic treatment. Each tooth has its own anchorage potential as well as propensity to move when force is applied. When teeth are used as anchorage, the untoward movements of the anchoring units may result in the prolonged treatment time, and unpredictable or less-than-ideal outcome. To maximize tooth-related anchorage, techniques such as differential torque, placing roots into the cortex of the bone, the use of various intraoral devices and/or extraoral appliances have been implemented. Implants, as they are in direct contact with bone, do not possess a periodontal ligament. As a result, they do not move when orthodontic/orthopedic force is applied, and therefore can be used as "absolute anchorage." This article describes different types of implants that have been used as orthodontic anchorage. Their clinical applications and limitations are also discussed. PMID:16463910

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  2. Two stage gear tooth dynamics program

    NASA Technical Reports Server (NTRS)

    Boyd, Linda S.

    1989-01-01

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

  3. Hydrogen interstitial in H-ion implanted ZnO bulk single crystals: Evaluation by elastic recoil detection analysis and electron paramagnetic resonance

    NASA Astrophysics Data System (ADS)

    Kaida, T.; Kamioka, K.; Nishimura, T.; Kuriyama, K.; Kushida, K.; Kinomura, A.

    2015-12-01

    The origins of low resistivity in H ion-implanted ZnO bulk single crystals are evaluated by elastic recoil detection analysis (ERDA), electron paramagnetic resonance (EPR), and Van der Pauw methods. The H-ion implantation (peak concentration: 5.0 × 1015 cm-2) into ZnO is performed using a 500 keV implanter. The maximum of the concentration of the implanted H estimated by a TRIM simulation is at 3600 nm in depth. The resistivity decreases from ∼103 Ω cm for un implanted ZnO to 6.5 Ω cm for as-implanted, 2.3 × 10-1 Ω cm for 200 °C annealed, and 3.2 × 10-1 Ω cm for 400 °C annealed samples. The ERDA measurements can evaluate the concentration of hydrogens which move to the vicinity of the surface (surface to 300 nm or 100 nm) because of the diffusion by the annealing at 200 °C and 400 °C. The hydrogen concentration near the surface estimated using the 2.0 MeV helium beam is ∼3.8 × 1013 cm-2 for annealed samples. From EPR measurements, the oxygen vacancy of +charge state (Vo+) is observed in as-implanted samples. The Vo+ related signal (g = 1.96) observed under no illumination disappears after successive illumination with a red LED and appears again with a blue light illumination. The activation energy of as-implanted, 200 °C annealed, and 400 °C annealed samples estimated from the temperature dependence of carrier concentration lies between 29 meV and 23 meV, suggesting the existence of H interstitial as a shallow donor level.

  4. Thermal and ion beam diffusion constants of Sb impurity implanted into <100> Ni single crystal

    NASA Astrophysics Data System (ADS)

    Belattar, A.; Stephens, G. A.; Cardwell, P. D.

    1995-08-01

    In previous investigations (A. Belattar et al., Nucl. Instr. and Meth. B 88 (1994) 394; B 93 (1994) 261) the annealing of the surface amorphous layer produced in <100> Ni crystal by implantation of 40 keV Sb 2+ to a fluence of 10 17 ions cm -2 was observed to occur in two distinct stages irrespective of whether the anneal process was due to an isochronal anneal in the temperature range 250 to 1100C or whether the process involved the high energy irradiation with 1.5 MeV Ar or Xe ions at a constant temperature of 350C. In this study the diffusion of the Sb was monitored by observing the Sb profile using the Rutherford backscattering technique. A computer fitting procedure was adopted to quantitatively determine the standard deviation of the width of the Sb profile (?), the results of which showed that this is a good parameter for monitoring the various diffusion processes. The results of the analysis show that in the case of the first anneal stage the diffusion is relatively slow, but that there is evidence that some form of segregation of the Sb impurity occurs; this is most pronounced during a prolonged isothermal anneal carried out at 350C. The second rapid anneal stage is accompanied by an equally rapid diffusion of the Sb impurities. In the case of the isochronal anneal, the activation energy for the diffusion process was measured to be 2.0 eV, which is not incompatible with a vacancy diffusion mechanism. In the case of the ion beam annealing processes, the monitoring of ? clearly showed a considerable enhancement of the main diffusion process of the Sb impurity which is directly related to the vacancies produced by the incident high energy irradiation.

  5. Microflora around teeth and dental implants

    PubMed Central

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

    2012-01-01

    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 (α=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. PMID:22623941

  6. Smoking and dental implants

    PubMed Central

    Kasat, V.; Ladda, R.

    2012-01-01

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

  7. A Single-Chip Full-Duplex High Speed Transceiver for Multi-Site Stimulating and Recording Neural Implants.

    PubMed

    Mirbozorgi, S Abdollah; Bahrami, Hadi; Sawan, Mohamad; Rusch, Leslie A; Gosselin, Benoit

    2016-06-01

    We present a novel, fully-integrated, low-power full-duplex transceiver (FDT) to support high-density and bidirectional neural interfacing applications (high-channel count stimulating and recording) with asymmetric data rates: higher rates are required for recording (uplink signals) than stimulation (downlink signals). The transmitter (TX) and receiver (RX) share a single antenna to reduce implant size and complexity. The TX uses impulse radio ultra-wide band (IR-UWB) based on an edge combining approach, and the RX uses a novel 2.4-GHz on-off keying (OOK) receiver. Proper isolation (>20 dB) between the TX and RX path is implemented 1) by shaping the transmitted pulses to fall within the unregulated UWB spectrum (3.1-7 GHz), and 2) by space-efficient filtering (avoiding a circulator or diplexer) of the downlink OOK spectrum in the RX low-noise amplifier. The UWB 3.1-7 GHz transmitter can use either OOK or binary phase shift keying (BPSK) modulation schemes. The proposed FDT provides dual band 500-Mbps TX uplink data rate and 100 Mbps RX downlink data rate, and it is fully integrated into standard TSMC 0.18- μm CMOS within a total size of 0.8 mm(2). The total measured power consumption is 10.4 mW in full duplex mode (5 mW at 100 Mbps for RX, and 5.4 mW at 500 Mbps or 10.8 pJ/bit for TX). Additionally, a 3-coil inductive link along with on-chip power management circuits allows to powering up the implantable transceiver wirelessly by delivering 25 mW extracted from a 13.56-MHz carrier signal, at a total efficiency of 41.6%. PMID:26469635

  8. Fabrication of H+ implanted channel waveguides in Y3Al5O12:Nd,Tm single crystal buried epitaxial layers for infrared to blue upconversion laser systems

    NASA Astrophysics Data System (ADS)

    Szachowicz, Marta; Moretti, Paul; Joubert, Marie-France; Couchaud, Maurice; Ferrand, Bernard

    2007-01-01

    Fabrication and intense infrared to blue upconversion emission of proton-implanted Tm3+, Nd3+:Y3Al5O12 (YAG) channel waveguides are reported for the first time to authors' knowledge. The single or multiple implanted channels are buried by positive induced index change in stacked planar layers grown by liquid-phase epitaxy on pure YAG substrates. The Nd3+ codoping considerably enhances the IR to blue upconversion emission of Tm3+ ions after excitation in resonance with either Nd3+ or Tm3+ absorption transition around 800nm.

  9. Reproducibility of peri-implant probing using a force-controlled probe.

    PubMed

    Eickholz, P; Grotkamp, F L; Steveling, H; Mhling, J; Staehle, H J

    2001-04-01

    The aim of the present study was to evaluate the reproducibility of probing depth (PD) and vertical attachment level (PAL-V) measurements at endosseous implants. Twenty partially edentulous patients who had received 44 Frialit-2 and 30 Astra implants between 1994 and 1996 were examined. At all teeth and implants, clinical parameters (GI, PlI, PD, PAL-V) were measured at 6 sites using the flexible plastic version of the universal explorer TPS probe. At the implants and at teeth that were in similar locations compared to the implants, PD and PAL-V measurements were repeated. For each of the 20 probes that had been used for clinical examination of the 20 patients, the probing force was assessed using a precision balance. As a measure of intraexaminer reproducibility, the following standard deviations of single PD and PAL-V measurements were calculated: Frialit-2: 0.71/0.74 mm; Astra: 0.72/0.75 mm; tooth: 0.59/0.57 mm (PD/PAL-V). Stepwise multiple regression analysis revealed implant/tooth position and GI to influence PD and PAL-V measurement error (P<0.001). At anterior teeth, a lower variability was observed than at posterior teeth (P<0.001). PD and PAL-V measurement error were higher at implants than at teeth and influenced by patients. The respective models explained 13% and 17% of the variability of the dependent variable (PD/PAL-V), respectively. Intraexaminer variability of PD and PAL-V measurements at implants tended to be higher than at teeth. Multivariate analysis of variance revealed probe and probe holder to statistically significantly (P<0.001) influence probing force. However, the differences in probing force between the various probe heads were very small. They reached a maximum of 0.054 N between probe 3 and 14 and may be looked upon as clinically irrelevant. PMID:11251665

  10. Autogenous wisdom tooth transplantation: A case series with 6-9 months follow-up

    PubMed Central

    Nim?enko, Tatjana; Omerca, Gravydas; Bramanti, Ennio; Cervino, Gabriele; Laino, Luigi; Cicci, Marco

    2014-01-01

    Tooth transplantation can be considered a valid and predictable treatment option for rehabilitating young patients with permanent teeth loss. This study presents several cases of successful autogenous tooth transplantation with a 6-9 months follow-up. Tooth auto-transplantation can be considered a reasonable option for replacing missing teeth when a donor tooth is available. The auto-transplantation of a right mandibular third molar with compromised function and esthetics to replace the residual roots resulting from coronal destruction due to extensive carious lesion of the second molar in the same quadrant as shown in the presented cases can result a viable treatment alternative especially in a young patient that cannot undergo dental implant therapy. Transplantation of mature third molar seems to be a promising method for replacing a lost permanent molar tooth and restoring esthetics and function. This clinical procedure showed excellent functional and esthetical long-term results in the analyzed cases. PMID:25540668

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

    SciTech Connect

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

    2011-12-23

    Nuclear reaction analysis (NRA) of carbon-implanted ZnO bulk single crystals (carbon concentration: 1.5x10{sup 20} cm{sup -3}), in conjunction with the channeling technique, using the {sup 12}C(d,p){sup 13}C and {sup 16}O(d,p){sup 17}O reactions shows the presence of the interstitial carbon (C{sub i}) and the occupancy of substitute sites of oxygen atoms. These results suggest that the variation in resistivity from the order of 10{sup 4} {Omega}cm(for un-implanted samples) to that of 10 {Omega}cm (for as-implanted ones) is attributed to the C{sub i} and/or its complex defects, which would act as a shallow donor in ZnO.

  12. 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)

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

    2011-12-01

    Nuclear reaction analysis (NRA) of carbon-implanted ZnO bulk single crystals (carbon concentration: 1.51020cm-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.

  13. Electron Spin Resonance Experiments on a Single Electron in Silicon Implanted with Phosphorous

    NASA Astrophysics Data System (ADS)

    Luhman, Dwight R.; Nguyen, K.; Tracy, L. A.; Carr, S.; Borchardt, J.; Bishop, N.; Ten Eyck, G.; Pluym, T.; Wendt, J.; Lilly, M. P.; Carroll, M. S.

    2015-03-01

    In this talk we will discuss the results of our ongoing experiments involving electron spin resonance (ESR) on a single electron in a natural silicon sample. The sample consists of an SET, defined by lithographic polysilicon gates, coupled to nearby phosphorous donors. The SET is used to detect charge transitions and readout the spin of the electron being investigated with ESR. The measurements were done with the sample at dilution refrigerator temperatures in the presence of a 1.3 T magnetic field. We will present data demonstrating Rabi oscillations of a single electron in this system as well as measurements of the coherence time, T2. We will also discuss our results using these and various other pulsing schemes in the context of a donor-SET system. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  14. Peri-implant esthetics assessment and management

    PubMed Central

    Balasubramaniam, Aarthi S.; Raja, Sunitha V.; Thomas, Libby John

    2013-01-01

    Providing an esthetic restoration in the anterior region of the mouth has been the basis of peri-implant esthetics. To achieve optimal esthetics, in implant supported restorations, various patient and tooth related factors have to be taken into consideration. Peri-implant plastic surgery has been adopted to improve the soft tissue and hard tissue profiles, during and after implant placement. The various factors and the procedures related to enhancement of peri-implant esthetics have been discussed in this review article. PMID:23878557

  15. Fabrication of barrier-type slab waveguides in Er3+-doped tellurite glass by single and double energy MeV N+ ion implantation

    NASA Astrophysics Data System (ADS)

    Bnysz, I.; Zolnai, Z.; Pelli, S.; Berneschi, S.; Nunzi-Conti, G.; Fried, M.; Lohner, T.; Petrik, P.; Brenci, M.; Righini, G. C.

    2012-01-01

    Ion implantation proved to be a universal technique for producing waveguides in most optical materials. Tellurite glasses are good hosts of rare-earth elements for the development of fibre and integrated optical amplifiers and lasers covering all the main telecommunication bands. Er3+- doped tellurite glasses are good candidates for the fabrication of broadband amplifiers in wavelength division multiplexing around 1.55 ?m, as they exhibit large stimulated cross sections and broad emission bandwidth. Fabrication of channel waveguides in such a material via N+ ion implantation was reported recently. Parameters of waveguide fabrication in an Er-doped tungsten-tellurite glass via implantation of N+ ions were optimized. First single-energy implantation at 3.5 MeV with fluences between 1.1016 and 8.1016 ions/cm2 was applied. Waveguide operation up to 1.5 ?m was observed. Then double-energy implantations at a fixed upper energy of 3.5 MeV and lower energies between 2.5 and 3.0 MeV were performed to suppress leaky modes by increasing barrier width. Improvement of waveguide characteristics was found by m-line spectroscopy and spectroscopic ellipsometry.

  16. Dental Implant Systems

    PubMed Central

    Oshida, Yoshiki; Tuna, Elif B.; Aktören, Oya; Gençay, Koray

    2010-01-01

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

  17. Risk Assessment for Tooth Wear.

    PubMed

    Kontaxopoulou, Isavella; Alam, Sonia

    2015-08-01

    Tooth wear has an increasing prevalence in the UK population. The aetiology is commonly multifactorial, and the aetiopathology is through a combination of erosion, attrition, abrasion and abfraction. Erosion is associated with intrinsic or extrinsic acids, and therefore subjects with reflux disease and eating disorders are at increased risk. Fruit juice, fruits and carbonated drink consumption, frequency of consumption and specific habits are also risk factors. Attrition is more prevalent in bruxists. Other habits need to be considered when defining the risk of tooth wear. Abrasion is usually associated with toothbrushing and toothpastes, especially in an already acidic environment. Patients with extensive lesions that affect dentin may be at higher risk, as well as those presenting with unstained lesions. Monitoring of the progress of tooth wear is recommended to identify those with active tooth wear. Indices for tooth wear are a helpful aid. PMID:26556515

  18. Characterization and quantification of proteins secreted by single human embryos prior to implantation.

    PubMed

    Poli, Maurizio; Ori, Alessandro; Child, Tim; Jaroudi, Souraya; Spath, Katharina; Beck, Martin; Wells, Dagan

    2015-11-01

    The use of in vitro fertilization (IVF) has revolutionized the treatment of infertility and is now responsible for 1-5% of all births in industrialized countries. During IVF, it is typical for patients to generate multiple embryos. However, only a small proportion of them possess the genetic and metabolic requirements needed in order to produce a healthy pregnancy. The identification of the embryo with the greatest developmental capacity represents a major challenge for fertility clinics. Current methods for the assessment of embryo competence are proven inefficient, and the inadvertent transfer of non-viable embryos is the principal reason why most IVF treatments (approximately two-thirds) end in failure. In this study, we investigate how the application of proteomic measurements could improve success rates in clinical embryology. We describe a procedure that allows the identification and quantification of proteins of embryonic origin, present in attomole concentrations in the blastocoel, the enclosed fluid-filled cavity that forms within 5-day-old human embryos. By using targeted proteomics, we demonstrate the feasibility of quantifying multiple proteins in samples derived from single blastocoels and that such measurements correlate with aspects of embryo viability, such as chromosomal (ploidy) status. This study illustrates the potential of high-sensitivity proteomics to measure clinically relevant biomarkers in minute samples and, more specifically, suggests that key aspects of embryo competence could be measured using a proteomic-based strategy, with negligible risk of harm to the living embryo. Our work paves the way for the development of "next-generation" embryo competence assessment strategies, based on functional proteomics. PMID:26471863

  19. Characterization and quantification of proteins secreted by single human embryos prior to implantation

    PubMed Central

    Poli, Maurizio; Ori, Alessandro; Child, Tim; Jaroudi, Souraya; Spath, Katharina; Beck, Martin; Wells, Dagan

    2015-01-01

    The use of in vitro fertilization (IVF) has revolutionized the treatment of infertility and is now responsible for 1–5% of all births in industrialized countries. During IVF, it is typical for patients to generate multiple embryos. However, only a small proportion of them possess the genetic and metabolic requirements needed in order to produce a healthy pregnancy. The identification of the embryo with the greatest developmental capacity represents a major challenge for fertility clinics. Current methods for the assessment of embryo competence are proven inefficient, and the inadvertent transfer of non-viable embryos is the principal reason why most IVF treatments (approximately two-thirds) end in failure. In this study, we investigate how the application of proteomic measurements could improve success rates in clinical embryology. We describe a procedure that allows the identification and quantification of proteins of embryonic origin, present in attomole concentrations in the blastocoel, the enclosed fluid-filled cavity that forms within 5-day-old human embryos. By using targeted proteomics, we demonstrate the feasibility of quantifying multiple proteins in samples derived from single blastocoels and that such measurements correlate with aspects of embryo viability, such as chromosomal (ploidy) status. This study illustrates the potential of high-sensitivity proteomics to measure clinically relevant biomarkers in minute samples and, more specifically, suggests that key aspects of embryo competence could be measured using a proteomic-based strategy, with negligible risk of harm to the living embryo. Our work paves the way for the development of “next-generation” embryo competence assessment strategies, based on functional proteomics. PMID:26471863

  20. Modulatory effects by neodymium-doped yttrium aluminum garnet laser on fibroblast attachment to single rooted tooth surfaces following ultrasonic scaling and root planning: An in vitro study

    PubMed Central

    Negi, Shanta; Krishnamurthy, Malathi; Ganji, Kiran Kumar; Pendor, Sunil

    2015-01-01

    Context: One of the most important goals of periodontal therapy is connective tissue reattachment to previously diseased root surfaces. In the recent years, laser therapy has been considered as an important tool in improving the treatment of periodontal disease. Aims: To evaluate the neodymium-doped yttrium aluminum garnet (Nd: YAG) lasers effects on root surfaces affected by periodontal disease and compare this treatment with scaling and root planning (SRP) in terms of fibroblast attachment. Materials and Methods: A sample of 30 single-rooted human teeth extracted because of advanced periodontal disease was used in this study. Sixty specimens obtained by longitudinal sectioning were randomly divided in three groups. Group A control (untreated); Group B SRP; Group C laser (Nd: YAG) and ultrasonic scaling. All specimens were incubated with fibroblast suspension and then fixed and observed under scanning electron microscope. Results: With a median of 8, the control group (Group A) exhibited the least number of total fibroblasts among all the three groups. The laser and scaling - treated group (Group C) showed the highest number of fibroblasts (median = 49, mean standard deviation [SD] = 48.28 17.18), followed by SRP only (Group B, median = 22, mean SD = 22.24 8.67). Conclusions: Nd: YAG laser irradiation at specific energy densities can be used as a useful tool to condition the root surfaces, enhancing fibroblast attachment. Hence aiding in re-establishment of the connective tissue attachment to the root surfaces of previously diseased teeth. PMID:25810589

  1. Social Determinants of Tooth Loss

    PubMed Central

    Gilbert, Gregg H; Paul duncan, R; Shelton, Brent J

    2003-01-01

    Objectives To quantify racial and socioeconomic status (SES) disparities in oral health, as measured by tooth loss, and to determine the role of dental care use and other factors in explaining disparities. Data Sources/Study Setting The Florida Dental Care Study, comprising African Americans (AAs) and non-Hispanic whites 45 years old or older who had at least one tooth. Study Design We used a prospective cohort design. Relevant population characteristics were grouped by predisposing, enabling, and need variables. The key outcome was tooth loss, a leading measure of a population's oral health, looked at before and after entering the dental care system. Tooth-specific data were used to increase inferential power by relating the loss of individual teeth to the disease level on those teeth. Data Collection Methods In-person interviews and clinical examinations were done at baseline, 24, and 48 months, with telephone interviews every 6 months. Principal Findings African Americans and persons of lower SES reported more new dental symptoms, but were less likely to obtain dental care. When they did receive care, they were more likely to experience tooth loss and less likely to report that dentists had discussed alternative treatments with them. At the first stage of analysis, differences in disease severity and new symptoms explained tooth loss disparities. Racial and SES differences in attitudes toward tooth loss and dental care were not contributory. Because almost all tooth loss occurs by means of dental extraction, the total effects of race and SES on tooth loss were artificially minimized unless disparities in dental care use were taken into account. Conclusions Race and SES are strong determinants of tooth loss. African Americans and lower SES persons had fewer teeth at baseline and still lost more teeth after baseline. Tooth-specific case-mix adjustment appears, statistically, to explain social disparity variation in tooth loss. However, when social disparities in dental care use are taken into account, social disparities in tooth loss that are not directly due to clinical circumstance become evident. This is because AAs and lower SES persons are more likely to receive a dental extraction once they enter the dental care system, given the same disease extent and severity. This phenomenon underscores the importance of understanding how disparities in health care use, dental insurance coverage, and service receipt contribute to disparities in health. Absent such understanding, the total effects of race and SES on health can be underestimated. PMID:14727800

  2. Partial tooth gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2010-01-01

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

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

    PubMed

    Kawarasaki, T; Enya, S; Otsu, Y

    2012-12-01

    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

  4. Coarsening model of cavity nucleation and thin film delamination from single-crystal BaTiO3 with proton implantation

    NASA Astrophysics Data System (ADS)

    Hong, Jung-Wuk; Pyeon, Jae-Ho; Tedesco, Joseph W.; Park, Young-Bae

    2007-06-01

    The layer splitting mechanism of a proton implanted single crystal ferroelectric BaTiO3 thin film layer from its bulk BaTiO3 substrate has been investigated. The single crystal BaTiO3 thin film layer splits as the hydrogen gas diffuses and the internal cavity pressure increases. Ripening mechanism driven by the pressurized hydrogen in the implantation-induced damage zone makes coarsening of the cavities and causes the delamination of the thin layer during the annealing. A unique criterion relation of blister nucleation and evolution has been derived and a simplified debonding criterion is proposed in terms of dimensionless parameters based on the force equilibrium condition. A numerical simulation of two-bubble evolution and delamination of thin film is performed using a finite element method.

  5. Key systemic and environmental risk factors for implant failure.

    PubMed

    Dawson, Dolphus R; Jasper, Samuel

    2015-01-01

    Dental implants are an important treatment option for patients interested in replacing lost or missing teeth. Although a robust body of literature has reviewed risk factors for tooth loss, the evidence for risk factors associated with dental implants is less well defined. This article focuses on key systemic risk factors relating to dental implant failure, as well as on perimucositis and peri-implantitis. PMID:25434557

  6. Restoration of divergent implants with a 2-piece screw-retained fixed, complete dental implant prostheses.

    PubMed

    Pelekanos, Stavros; Pozidi, Georgia; Kourtis, Stefanos

    2016-04-01

    Restoring a severely resorbed maxilla is challenging because of poor bone quality and the resorptive pattern that follows tooth loss. When bone augmentation is not possible, implants are placed in suboptimal positions, making the prosthetic rehabilitation more complex. This report presents the steps used to rehabilitate a severely resorbed maxilla with divergent implants, using an implant-supported 2-piece screw-retained prosthesis. PMID:26597464

  7. TEM investigation of the surface layer structure [111]B2 of the single NiTi crystal modified by the Si-ion beam implantation

    NASA Astrophysics Data System (ADS)

    Girsova, S. L.; Poletika, T. M.; Meisner, S. N.; Meisner, L. L.

    2015-10-01

    The study was carried on for the single NiTi crystals subjected to the Si-ion beam implantation. Using the transmission electron microscopy technique (TEM), the surface layer structure [111]B2 was examined for the treated material. The modified near-surface sublayers were found to have different composition. Thus the uppermost sublayer contained mostly oxides; the lower-lying modified sublayer material was in an amorphous state and the thin underlying sublayer had a defect structure.

  8. Clinical evaluation of ridge augmentation using autogenous tooth bone graft material: case series study

    PubMed Central

    Lee, Ji-Young; Kim, Young-Kyun; Choi, Joon-Ho

    2013-01-01

    Objectives Interest in bone graft material has increased with regard to restoration in cases of bone defect around the implant. Autogenous tooth bone graft material was developed and commercialized in 2008. In this study, we evaluated the results of vertical and horizontal ridge augmentation with autogenous tooth bone graft material. Materials and Methods This study targeted patients who had vertical or horizontal ridge augmentation using AutoBT from March 2009 to April 2010. We evaluated the age and gender of the subject patients, implant stability, adjunctive surgery, additional bone graft material and barrier membrane, post-operative complication, implant survival rate, and crestal bone loss. Results We performed vertical and horizontal ridge augmentation using powder- or block-type autogenous tooth bone graft material, and implant placement was performed on nine patients (male: 7, female: 2). The average age of patients was 49.8812.98 years, and the post-operative follow-up period was 355.31 months. Post-operative complications included wound dehiscence (one case), hematoma (one case), and implant osseointegration failure (one case; survival rate: 96%); however, there were no complications related to bone graft material, such as infection. Average marginal bone loss after one-year loading was 0.120.19 mm. Therefore, excellent clinical results can be said to have been obtained. Conclusion Excellent clinical results can be said to have been obtained with vertical and horizontal ridge augmentation using autogenous tooth bone graft material. PMID:24471036

  9. Decoronation for the management of an ankylosed young permanent tooth.

    PubMed

    Sapir, Shabtai; Shapira, Joseph

    2008-02-01

    Replacement resorption rate is a variable process, and is dependent on age, basal metabolic rate, extra-alveolar time, treatment prior to replantation, amount of root dentin, severity of trauma, and extent of periodontal ligament necrosis. In patients 7-16 years old a tooth is lost 3-7 years after the onset of root resorption. The complications that may develop as a consequence of ankylosis of a permanent incisor in children are due to the inevitable early loss of the traumatized tooth and local arrest of alveolar bone development. An ankylosed tooth should be removed before the changes become so pronounced that they compromise future prosthetic treatment. The treatment options may involve: interceptive regenerative treatment, early extraction of the ankylosed tooth, orthodontic space closure, intentional replantation, extraction of the ankylosed tooth followed with immediate ridge augmentation/preservation, auto-transplantation, single tooth dento-osseous osteotomy, and decoronation. The purpose of this article was to review the considerations involved in the decision-making concerning the use of the decoronation technique for the treatment of a permanent incisor diagnosed as ankylosed. PMID:18173685

  10. Immediate 3-dimensional ridge augmentation after extraction of periodontally hopeless tooth using chinblock graft

    PubMed Central

    Desai, Ankit; Thomas, Raison; A. Baron, Tarunkumar; Shah, Rucha; Mehta, Dhoom-Singh

    2015-01-01

    Background The aim of the present study was to evaluate clinically and radiographically, the efficacy of immediate ridge augmentation to reconstruct the vertical and horizontal dimensions at extraction sites of periodontally hopeless tooth using an autogenous chin block graft. Material and Methods A total of 11 patients (7 male & 4 female) with localized advanced bone loss around single rooted teeth having hopeless prognosis and indicated for extraction were selected for the study. The teeth were atraumatically extracted and deficient sites were augmented using autogenous chin block graft. Parameters like clinically soft tissue height - width and also radiographic ridge height -width were measured before and 6 months after augmentation. Obtained results were tabulated and analysed statistically. Results After 6 months of immediate ridge augmentation, the mean gain in radiographic vertical height and horizontal width was 7.64 + 1.47 mm (P = 0.005) and 5.28 + 0.46 mm (P = 0.007) respectively which was found to be statistically significant (P < 0.05). Mean change of width gain of 0.40mm and height loss of 0.40mm of soft tissue parameters, from the baseline till completion of the study at 6 months was observed. Conclusions The present study showed predictable immediate ridge augmentation with autogenous chin block graft at periodontally compromised extraction site. It can provide adequate hard and soft tissue foundation for perfect 3-Dimensional prosthetic positioning of implant in severely deficient ridges. Key words:Immediate ridge augmentation, periondontally hopeless tooth, autogenous chin graft, dental implant. PMID:26644832

  11. Cost-effectiveness of Anterior Implants versus Fixed Dental Prostheses

    PubMed Central

    Zitzmann, N.U.; Krastl, G.; Weiger, R.; Kühl, S.; Sendi, P.

    2013-01-01

    For the restoration of an anterior missing tooth, implant-supported single crowns (ISCs) or fixed dental prostheses (FDPs) are indicated, but it is not clear which type of restoration is more cost-effective. A self-selected trial was performed with 15 patients with ISCs and 11 with FDPs. Patient preferences were recorded with visual analog scales before treatment, 1 month following restoration, and then annually. Quality-adjusted tooth years (QATYs) were estimated by considering the type of reconstruction for replacing the missing tooth and its effect on the adjacent teeth. A stochastic cost-effectiveness model was developed using Monte Carlo simulation. The expected costs and QATYs were summarized in cost-effectiveness acceptability curves. ISC was the dominant strategy, with a QATY increase of 0.01 over 3 years and 0.04 over 10 years with a higher probability of being cost-effective. While both treatment options provided satisfactory long-term results from the patient’s perspective, the lower initial costs, particularly laboratory fees, were responsible for the dominance of ISCs over FDPs. PMID:24158338

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

    PubMed Central

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

    2008-01-01

    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. PMID:19236990

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  14. Three-Dimensional Finite Element Analysis of Anterior Single Implant-Supported Prostheses with Different Bone Anchorages

    PubMed Central

    Verri, Fellippo Ramos; Santiago Júnior, Joel Ferreira; Almeida, Daniel Augusto de Faria; Verri, Ana Caroline Gonçales; de Souza Batista, Victor Eduardo; Lemos, Cleidiel Aparecido Araujo; Noritomi, Pedro Yoshito; Pellizzer, Eduardo Piza

    2015-01-01

    The aim of this study was to evaluate the stress distribution of monocortical and bicortical implant placement of external hexagon connection in the anterior region of the maxilla by 3D finite element analysis (FEA). 3D models were simulated to represent a bone block of anterior region of the maxilla containing an implant (4.0 × 10.0 mm) and an implant-supported cemented metalloceramic crown of the central incisor. Different techniques were tested (monocortical, bicortical, and bicortical associated with nasal floor elevation). FEA was performed in FEMAP/NeiNastran software using loads of 178 N at 0°, 30°, and 60° in relation to implant long axis. The von Mises, maximum principal stress, and displacement maps were plotted for evaluation. Similar stress patterns were observed for all models. Oblique loads increased the stress concentration on fixation screws and in the cervical area of the implants and bone around them. Bicortical technique showed less movement tendency in the implant and its components. Cortical bone of apical region showed increase of stress concentration for bicortical techniques. Within the limitations of this study, oblique loading increased the stress concentrations for all techniques. Moreover, bicortical techniques showed the best biomechanical behavior compared with monocortical technique in the anterior maxillary area. PMID:26351654

  15. Esthetic management of double tooth associated with talon cusp using a laminate veneer.

    PubMed

    Cordeiro, Wayne Jos Batista; do Couto, Cintia Fernandes; Barros, Renata Nunes; Zarranz, Laila; Jorge, Mnica Zacharias; de Gouva, Cresus Vnicius Depes

    2014-01-01

    Double tooth and talon cusp are tooth shape anomalies with rare co-occurrences in a single tooth. Double tooth is a developmental anomaly that leads to the eruption of fused teeth and may contribute to compromised esthetics, pain, caries, and tooth crowding. Talon cusp is a rare developmental extra cusp-like projection on the cingulum area that may cause functional and esthetic problems. Differential diagnosis of these anomalies may be complicated. A multidisciplinary approach for the esthetic and functional rehabilitation of double teeth is important. Various treatment methods have been described in the literature for the different types and morphological variations of double teeth. The purpose of this paper is to report the case of an unusual combination of double tooth and talon cusp on a permanent maxillary incisor and describe its esthetic and functional rehabilitation using a porcelain laminate veneer. PMID:25514262

  16. New Perspectives on Tooth Wear

    PubMed Central

    Lucas, Peter W.; Omar, Ridwaan

    2012-01-01

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

  17. Rapid maxillary expansion assisted by palatal mini-implants in adolescents - preliminary study.

    PubMed

    Chane-Fane, Caroline; Darqué, François

    2015-03-01

    Our preliminary clinical study compares the transverse skeletal and dento-alveolar modifications occurring after rapid maxillary expansion with purely dental anchorage or with dental anchorage assisted by palatal mini-implants, in endognathic adolescents aged 12 to 17. Nine patients were treated by means of tooth- and implant-supported expansion, and 7 others by means of a purely tooth-borne expander. The changes, 4 months after expansion, were measured on impressions and front-view X-rays in the 2 groups, and on three-dimensional X-rays for 6 patients treated by tooth- and implant-supported expansion. In our sample, tooth- and implant-supported expansion preserved the alveolar bone of 14/24 and gave rise to less buccal tipping of 16/26 than purely tooth-borne expansion. PMID:25665914

  18. The Human Sweet Tooth

    PubMed Central

    Reed, Danielle R; McDaniel, Amanda H

    2006-01-01

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

  19. Sinus augmentation at the time of molar tooth removal: modification of Jensen technique.

    PubMed

    Block, Michael S

    2015-06-01

    When a maxillary molar tooth needs to be removed, the treatment plan often includes subsequent dental implant placement. However, there may be less than 5mm of bone available in the central fossa region of the proposed implant site. This report describes a technique to use a precise osteotomy within the maxillary molar socket to mobilize a segment of bone and superiorly raise it to provide increased alveolar bone height using grafting. This technique eliminates the need for lateral window surgery. PMID:25659359

  20. Functional tooth restoration utilising split germs through re-regionalisation of the tooth-forming field.

    PubMed

    Yamamoto, Naomi; Oshima, Masamitsu; Tanaka, Chie; Ogawa, Miho; Nakajima, Kei; Ishida, Kentaro; Moriyama, Keiji; Tsuji, Takashi

    2015-01-01

    The tooth is an ectodermal organ that arises from a tooth germ under the regulation of reciprocal epithelial-mesenchymal interactions. Tooth morphogenesis occurs in the tooth-forming field as a result of reaction-diffusion waves of specific gene expression patterns. Here, we developed a novel mechanical ligation method for splitting tooth germs to artificially regulate the molecules that control tooth morphology. The split tooth germs successfully developed into multiple correct teeth through the re-regionalisation of the tooth-forming field, which is regulated by reaction-diffusion waves in response to mechanical force. Furthermore, split teeth erupted into the oral cavity and restored physiological tooth function, including mastication, periodontal ligament function and responsiveness to noxious stimuli. Thus, this study presents a novel tooth regenerative technology based on split tooth germs and the re-regionalisation of the tooth-forming field by artificial mechanical force. PMID:26673152

  1. Functional tooth restoration utilising split germs through re-regionalisation of the tooth-forming field

    PubMed Central

    Yamamoto, Naomi; Oshima, Masamitsu; Tanaka, Chie; Ogawa, Miho; Nakajima, Kei; Ishida, Kentaro; Moriyama, Keiji; Tsuji, Takashi

    2015-01-01

    The tooth is an ectodermal organ that arises from a tooth germ under the regulation of reciprocal epithelial-mesenchymal interactions. Tooth morphogenesis occurs in the tooth-forming field as a result of reaction-diffusion waves of specific gene expression patterns. Here, we developed a novel mechanical ligation method for splitting tooth germs to artificially regulate the molecules that control tooth morphology. The split tooth germs successfully developed into multiple correct teeth through the re-regionalisation of the tooth-forming field, which is regulated by reaction-diffusion waves in response to mechanical force. Furthermore, split teeth erupted into the oral cavity and restored physiological tooth function, including mastication, periodontal ligament function and responsiveness to noxious stimuli. Thus, this study presents a novel tooth regenerative technology based on split tooth germs and the re-regionalisation of the tooth-forming field by artificial mechanical force. PMID:26673152

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  3. The impact of transcatheter aortic valve implantation on left ventricular performance and wall thickness single-centre experience

    PubMed Central

    Szyma?ski, Piotr; D?browski, Maciej; Zakrzewski, Dariusz; Micha?ek, Piotr; Or?owska-Baranowska, Ewa; El-Hassan, Kamal; Chmielak, Zbigniew; Witkowski, Adam; Hryniewiecki, Tomasz

    2015-01-01

    Introduction Transcatheter aortic valve implantation (TAVI) is a treatment alternative for the elderly population with severe symptomatic aortic stenosis (AS) at high risk for surgical aortic valve replacement (SAVR). Aim To assess the impact of TAVI on echocardiographic parameters of left ventricular (LV) performance and wall thickness in patients subjected to the procedure in a single-centre between 2009 and 2013. Material and methods The initial group consisted of 170 consecutive patients with severe AS unsuitable for SAVR. Logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 21.73 12.42% and mean age was 79.9 7.5 years. Results The TAVI was performed in 167 (98.2%) patients. Mean aortic gradient decreased significantly more rapidly after the procedure (from 58.6 16.7 mm Hg to 11.9 4.9 mm Hg, p < 0.001). The LV ejection fraction (LVEF) significantly increased in both short-term and long-term follow-up (57 14% vs. 59 13%, p < 0.001 and 56 14% vs. 60 12%, p < 0.001, respectively). Significant regression of interventricular septum diameter at end-diastole (IVSDD) and end-diastolic posterior wall thickness (EDPWth) was noted in early (15.0 2.4 mm vs. 14.5 2.3 mm, p < 0.001 and 12.7 2.1 mm vs. 12.4 1.9 mm, p < 0.028, respectively) and late post-TAVI period (15.1 2.5 mm to 14.3 2.5 mm, p < 0.001 and 12.8 2.0 mm to 12.4 1.9 mm, p < 0.007, respectively). Significant paravalvular leak (PL) was noted in 21 (13.1%) patients immediately after TAVI and in 13 (9.6%) patients in follow-up (p < 0.001). Moderate or severe mitral regurgitation (msMR) was seen in 24 (14.9%) patients from the initial group and in 19 (11.8%) patients after TAVI (p < 0.001). Conclusions The TAVI had an immediate beneficial effect on LVEF, LV walls thickness, and the incidence of msMR. The results of the procedure are comparable with those described in other centres. PMID:25848369

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

    PubMed Central

    2014-01-01

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

  5. Clinical Management of Implant Prostheses in Patients with Bruxism

    PubMed Central

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

    2012-01-01

    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. PMID:22701484

  6. Definitive Presurgical CAD/CAM-Guided Implant-Supported Crown in an Esthetic Area.

    PubMed

    Barros, Vinicius de Magalhães; Costa, Natália Rafaela de Assis; Martins, Paulo Henrique Fonseca; Vasconcellos, Walison Arthuso; Discacciati, José Augusto César; Moreira, Allyson Nogueira

    2015-12-01

    This paper describes the digital workflow from cone beam computer tomography (CBCT) to the installation of a definitive presurgical zirconium individual crown in a 19-year-old woman requiring implant replacement of a maxillary right lateral incisor. The patient had agenesis of this tooth and had completed the orthodontic treatment. CBCT was conducted and diagnostic casts were digitized. Virtual planning was completed by defining a prosthetically driven implant and a stereolithographic surgical template was produced. Good adaptation of a stereolithographic surgical template was verified in the working cast. Implant and abutment were installed in this cast using a stereolithographic surgical template, and a CAD/CAM definitive zirconium crown was produced. Flapless computer-guided implant surgery was performed. The abutment was connected, and a definitive zirconium crown was cemented using resin cement. The digital workflow presented herein shows high accuracy for a virtually planned implant with flapless guided placement, allowing the successful delivery of a definitive presurgical zirconium single crown in an esthetic area in a single visit. The patient was revaluated after 1 year of function with an excellent outcome of the treatment. PMID:26963219

  7. Development of implant movement checker for determining dental implant stability.

    PubMed

    Wijaya, Sastra Kusuma; Oka, Hisao; Saratani, Keiji; Sumikawa, Takuya; Kawazoe, Takayoshi

    2004-07-01

    Noninvasive and nondestructive mobility assessment of dental implants is very important and useful for dental implantation diagnostic-aids. The development of implant movement (IM) checker based on microcontroller is presented in this paper. Data acquisition system and bender-type piezoelectric probe were used to improve measurement quality to the original tooth mobility (TM) tester. The adoption of a microcontroller and the use of a dental drill-sized measuring probe were sufficient in the reproducibility and reliability of the IM checker. When the implant was subjected to a constant force and amplitude, the acceleration of the model was detected using the measuring probe. The data acquisition system controlled for obtaining the appropriate acceleration signals based on the preload detection during measurement. Dental implant models of Molteno and Rigolac were made at different stiffness and were used to verify the reliability and validity of measurements. The values of measurements obtained by the IM checker were reliable and precise. The maximum error for perpendicular measurements was less than 12% measured by a new operator and decreased to 2% by an experienced operator. The IM checker was applied to monitor the stability of dental implantation, which compared the relative IM score of the new 5[see text] implant with the adjacent old 6 [see text] implant that had been used functionally for 3 years. PMID:15234687

  8. Importance of a distal proximal contact on load transfer by implant-supported single adjacent crowns in posterior region of the mandible: a photoelastic study

    PubMed Central

    de AGUIAR JNIOR, Fbio Afrnio; TIOSSI, Rodrigo; MACEDO, Ana Paula; de MATTOS, Maria da Gloria Chiarello; RIBEIRO, Ricardo Faria; RODRIGUES, Renata Cristina Silveira

    2013-01-01

    Objective This study aimed to evaluate the importance of a distal proximal contact on the load transfer to the posterior region of the mandible by non-splinted adjacent implant-supported crowns using photoelastic stress analysis. Material and Methods A rectangular model (68x30x15 mm) was made of polymethylmethacrylate resin to simulate half of the mandibular arch. One model was completed with resin replicas representing the first premolar and second molar and with two 3.75 mm dia.x11 mm internal hexagon threaded implants replacing the second premolar and first molar. The other model was manufactured in the same way but without the second molar. Both models were duplicated using photoelastic resin. The roots of the teeth replicas were covered with a layer of polyether impression material to simulate the periodontal ligament. Two different vertical loads were applied to the crowns as follows: 1 - single static point load alternately applied to the crowns replacing the second premolar and first molar (50 N); 2 - simultaneous static point loads applied to both of the crowns replacing the second premolar and first molar (100 N). The resulting isochromatic fringe pattern in the photoelastic model was monitored and photographed. Results All loading conditions studied showed that the presence of the second molar has changed the load transmission and the pattern of stresses. Conclusion Results showed that the presence of a second molar proximal contact can help minimize the stresses around the implants. PMID:24212984

  9. Prophylactic catheter ablation of ventricular tachycardia before cardioverter-defibrillator implantation in patients with non-ischemic cardiomyopathy: Clinical outcomes after a single endocardial ablation

    PubMed Central

    Suzuki, Atsushi; Yoshida, Akihiro; Takei, Asumi; Fukuzawa, Koji; Kiuchi, Kunihiko; Takami, Kaoru; Itoh, Mitsuaki; Imamura, Kimitake; Fujiwara, Ryudo; Nakanishi, Tomoyuki; Yamashita, Soichiro; Matsumoto, Akinori; Shimane, Akira; Okajima, Katsunori; Hirata, Ken-ichi

    2015-01-01

    Background Outcomes related to prophylactic catheter ablation (PCA) for ventricular tachycardia (VT) before implantable cardioverter-defibrillator (ICD) implantation in non-ischemic cardiomyopathy (NICM) are not well characterized. We assessed the efficacy of single endocardial PCA in NICM patients. Methods We retrospectively analyzed 101 consecutive NICM patients with sustained VT. We compared clinical outcomes of patients who underwent PCA (ABL group) with those who did not (No ABL group). Successful PCA was defined as no inducible clinical VT. We also compared the clinical outcomes of patients with successful PCA (PCA success group) with those of the No ABL group. Endpoints were appropriate ICD therapy (shock and anti-tachycardia pacing) and the occurrence of electrical storm (ES). Results PCA was performed in 42 patients, and it succeeded in 20. The time to ES occurrence was significantly longer in the ABL group than in the No ABL group (p=0.04). The time to first appropriate ICD therapy and ES occurrence were significantly longer in the PCA success group than in the No ABL group (p=0.02 and p<0.01, respectively). Conclusion Single endocardial PCA can decrease ES occurrence in NICM patients. However, high rates of VT recurrence and low success rates are issues to be resolved; therefore, the efficacy of single endocardial PCA is currently limited. PMID:26336545

  10. Tooth polishing: The current status

    PubMed Central

    Sawai, Madhuri Alankar; Bhardwaj, Ashu; Jafri, Zeba; Sultan, Nishat; Daing, Anika

    2015-01-01

    Healthy teeth and gums make a person feel confident and fit. As people go about their daily routines and with different eating and drinking habits, the tooth enamel turns yellowish or gets stained. Polishing traditionally has been associated with the prophylaxis procedure in most dental practices, which patients know and expect. However, with overzealous use of polishing procedure, there is wearing of the superficial tooth structure. This would lead to more accumulation of local deposits. Also, it takes a long time for the formation of the fluoride-rich layer of the tooth again. Hence, now-a-days, polishing is not advised as a part of routine oral prophylaxis procedure but is done selectively based on the patients’ need. The article here, gives an insight on the different aspects of the polishing process along with the different methods and agents used for the same. PMID:26392683

  11. Detecting Gear Tooth Fatigue Cracks in Advance of Complete Fracture

    NASA Technical Reports Server (NTRS)

    Zakrajsek, James J.; Lewicki, David G.

    1996-01-01

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

  12. Maxillary and mandibular immediately loaded implant-supported interim complete fixed dental prostheses on immediately placed dental implants with a digital approach: A clinical report.

    PubMed

    Lewis, Ryan C; Harris, Bryan T; Sarno, Robert; Morton, Dean; Llop, Daniel R; Lin, Wei-Shao

    2015-09-01

    This clinical report describes the treatment of maxillary and mandibular immediate implant placement and immediately loaded implant-supported interim complete fixed dental prostheses with a contemporary digital approach. The virtual diagnostic tooth arrangement eliminated the need for a customized radiographic template, and the diagnostic data collection required for computer-guided surgery (digital diagnostic impressions, digital photographs, and a cone beam-computed tomography [CBCT] scan) was completed in a single visit with improved workflow efficiency. Computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated surgical templates and interim prosthesis templates were made in a dental laboratory to facilitate computer-guided surgery and the immediate loading process. PMID:26050026

  13. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  14. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of

  15. Another Downside to Diabetes: Tooth Loss

    MedlinePLUS

    ... news/fullstory_156032.html Another Downside to Diabetes: Tooth Loss Dental care often overlooked, leading to worse ... physical toll associated with type 2 diabetes includes tooth loss, a new study finds. The risk of ...

  16. Orthodontic Tooth Movement: A Historic Prospective.

    PubMed

    Will, Leslie A

    2016-01-01

    The earliest report on orthodontic tooth movement in the English literature was published in 1911. Oppenheim carried out studies on baboons to determine what histologic changes occurred during tooth movement. Reitan and many others carried out research into the nature of tooth movement. The pressure-tension model of tooth movement developed from these studies, whereby the two sides of the tooth responded to forces as if in isolation. A second theory, proposed by Stuteville in 1938, was the hydraulic theory of tooth movement. In this theory, fluid from the vasculature, lymphatic system and intercellular spaces responds to the forces of tooth movement, damping the force and limiting movement. Bien and Baumrind expanded on this theory with their own studies in the 1960s. It is clear that both the pressure-tension and fluid flow concepts have merit, but considerable work needs to be done to ascertain the details so that tooth movement can be managed and controlled. PMID:26599117

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

    PubMed

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

    2014-08-01

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

  18. Surgical-prosthetic management of facial soft tissue defects on anterior single implant-supported restorations: a clinical report.

    PubMed

    Paniz, Gianluca; Mazzocco, Fabio

    2015-01-01

    The surgical correction of soft tissue defects on the facial aspects of dental implants is documented as an unpredictable procedure. Since the customization of the prosthetic emergence profile contributes significantly to the final esthetic outcome of the soft tissue, a combined surgical-prosthetic approach has been described in the literature. In the case presented in this article, a multidisciplinary approach was used to treat a patient's anterior sextant. It included the treatment of a previously placed implant, perfectly osseointegrated, with a 2 mm recession of the facial soft tissue. Two connective tissue grafting procedures were performed, in conjunction with the modification of the prosthetic profile of the provisional restoration and the definitive abutment. The final esthetic outcome satisfied the patient and resolved the main complaint, and is documented to have been stable for 5 years. PMID:25874274

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

    SciTech Connect

    Kumar, Ravi; Singh, Fouran; Angadi, Basavaraj; Choi, Ji-Won; Choi, Won-Kook; Jeong, Kwangho; Song, Jong-Han; Khan, M. Wasi; Srivastava, J. P.; Kumar, Ajay; Tandon, R. P.

    2006-12-01

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

  20. Efficacy of intraoperative vancomycin powder use in intrathecal baclofen pump implantation procedures: single institutional series in a high risk population.

    PubMed

    Ghobrial, George M; Thakkar, Vismay; Singhal, Saurabh; Oppenlander, Mark E; Maulucci, Christopher M; Harrop, James S; Jallo, Jack; Prasad, Srinivas; Saulino, Michael; Sharan, Ashwini D

    2014-10-01

    We aimed to assess the efficacy of intraoperative vancomycin powder in intrathecal baclofen pump placement patients, a high risk population. A retrospective review was conducted using prospectively collected data at an academic tertiary care unit. The neurosurgical adult patient population was queried for all intrathecal baclofen pump implantation procedures. Patients were then reviewed for the use of intraoperative crystalline vancomycin powder. Those with a history of prior surgical site infection, chronic systemic infections or osteomyelitis were excluded. Anhydrous, crystalline vancomycin was utilized in the wound bed after completion of implantation, distributed evenly in the case of multiple incisions. Patients received 500 mg or 1,000 mg of crystallized vancomycin, evenly distributed through the wound layers based on a 70 kg weight cutoff. Intraoperative institutional standards of infection prophylaxis were unchanged throughout the study period. Infection rate of baclofen pump placement prior to the use of vancomycin powder from 2001-2009 at the same institution was monitored. Wound infection rate was tracked for a 12 month postoperative period. Six patients out of 26 baclofen pump implantations (23%) in this cohort were identified to have seven infections despite vancomycin powder placement in the lumbar and catheter wounds. Prior infection rates have been investigated for intrathecal drug delivery systems from 2001 to 2009 at the same institution with an overall infection rate of 3% (8/274). The use of vancomycin powder in patients with implants in this series did not reduce infection rates compared to published historical controls, and was elevated compared to institutional controls. Further prospective study of this high risk patient population is warranted. PMID:24938386

  1. Biology of tooth replacement in amniotes

    PubMed Central

    Whitlock, John A; Richman, Joy M

    2013-01-01

    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 12 generations of teeth. Here, we review the mechanisms of tooth replacement in reptiles and mammals, and discuss in detail the current and historical theories on control of timing and pattern of tooth replacement and development. PMID:23788284

  2. Twelve-Month Results of a Single or Multiple Dexamethasone Intravitreal Implant for Macular Edema following Uncomplicated Phacoemulsification

    PubMed Central

    Abdolrahimzadeh, Solmaz; Fenicia, Vito; Maurizi Enrici, Maurizio; Plateroti, Pasquale; Cianfrone, Dora; Recupero, Santi Maria

    2015-01-01

    The clinical efficacy of one or two intravitreal injections of a continued deliverance dexamethasone 700??g implant in ten patients with persistent macular edema following uncomplicated phacoemulsification was evaluated. Complete ophthalmological examination and spectral domain optical coherence tomography were carried out. Follow-up was at day 7 and months 1, 2, 4, 6, 8, and 12. At baseline mean best corrected visual acuity was 62 Early Treatment Diabetic Retinopathy Study Chart letters, which showed statistically significant improvement at each follow-up, except at month 6, to reach 79 letters at month 12 (P = 0.018). Prior to treatment mean central foveal thickness was 622??m, which showed statistically significant improvement at each follow-up to reach a mean value of 282??m (P = 0.012) at month 12. Five patients received a second dexamethasone implant at month 7. Two patients were excluded from the study at months 4 and 8. Intraocular pressure remained stable during the study period with the exception of mild increase in two patients requiring topical therapy. In conclusion there was statistically significant improvement of best corrected visual acuity and mean central foveal thickness with one or two intravitreal dexamethasone implants over 12 months. PMID:26509151

  3. Surgical Management of Fractured Orthodontic Mini- Implant- A Case Report

    PubMed Central

    Jain, Anoop; Sumra, Nida

    2015-01-01

    The idea of absolute anchorage has always been an elusive goal for clinicians. Orthodontic mini-implants or temporary anchorage devices allow tooth movements previously thought to be impossible or difficult. Although extensive literature exists on use of temporary anchorage devices, their failures have been hardly focused upon, especially implant fracture. The following case report describes successful management of fractured orthodontic mini-implant. PMID:25738088

  4. Cochlear Implants

    MedlinePLUS

    ... Arts A cochlear implant is a small, complex electronic device that can help to provide a sense ... that can answer questions and provide printed or electronic information on cochlear implants: Cochlear implants Assistive technology ...

  5. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Porcelain tooth. 872.3920 Section 872.3920 Food... DEVICES DENTAL DEVICES Prosthetic Devices 872.3920 Porcelain tooth. (a) Identification. A porcelain tooth is a prefabricated device made of porcelain powder for clinical use ( 872.6660) intended for...

  6. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Porcelain tooth. 872.3920 Section 872.3920 Food... DEVICES DENTAL DEVICES Prosthetic Devices 872.3920 Porcelain tooth. (a) Identification. A porcelain tooth is a prefabricated device made of porcelain powder for clinical use ( 872.6660) intended for...

  7. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Porcelain tooth. 872.3920 Section 872.3920 Food... DEVICES DENTAL DEVICES Prosthetic Devices 872.3920 Porcelain tooth. (a) Identification. A porcelain tooth is a prefabricated device made of porcelain powder for clinical use ( 872.6660) intended for...

  8. Tooth Avulsion in the School Setting

    ERIC Educational Resources Information Center

    Krause-Parello, Cheryl A.

    2005-01-01

    Tooth avulsions occur when a tooth is displaced from its socket. Tooth avulsions are common dental injuries that may occur before, during, or after school. Therefore, it is essential that school nurses be well prepared to intervene when such a dental emergency arises. It is also imperative that school nurses and school personnel are fully equipped

  9. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Porcelain tooth. 872.3920 Section 872.3920 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3920 Porcelain tooth. (a) Identification. A porcelain tooth is a prefabricated device made of porcelain powder for clinical use (§ 872.6660) intended for...

  10. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Porcelain tooth. 872.3920 Section 872.3920 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3920 Porcelain tooth. (a) Identification. A porcelain tooth is a prefabricated device made of porcelain powder for clinical use (§ 872.6660) intended for...

  11. Correction of bone and softtissue deformity of the single implant in the aesthetic zone: a case treated with alveolar ridge preservation, modified roll technique and a digitally coded healing abutment.

    PubMed

    Dhima, M

    2014-06-01

    The correction of soft tissue deformity and aesthetic rehabilitation of a single implant in the aesthetic zone with a combination of periodontal and prosthodontic approaches is described. Soft tissue deformity was corrected resulting in significant soft tissue volume increase and eliminated the need for prosthetic gingival replacement. A two stage implant placement protocol, ridge preservation and a soft tissue augmentation flap design preserved epithelium attachment to the connective tissues. Use of a digitally coded healing abutment preserved the newly established soft tissue volume, allowed impression making without implant component removal, and minimized trauma to the newly established soft tissue architecture. PMID:25134361

  12. Diagnosis of cracked tooth syndrome

    PubMed Central

    Mathew, Sebeena; Thangavel, Boopathi; Mathew, Chalakuzhiyil Abraham; Kailasam, SivaKumar; Kumaravadivel, Karthick; Das, Arjun

    2012-01-01

    The incidences of cracks in teeth seem to have increased during the past decade. Dental practitioners need to be aware of cracked tooth syndrome (CTS) in order to be successful at diagnosing CTS. Early diagnosis has been linked with successful restorative management and predictably good prognosis. The purpose of this article is to highlight factors that contribute to detecting cracked teeth. PMID:23066261

  13. Charcot-Marie-Tooth Disease

    MedlinePLUS

    Charcot-Marie-Tooth disease (CMT) is a group of genetic nerve disorders. It is named after the three doctors who first identified it. ... a nerve biopsy. There is no cure. The disease can be so mild you don't realize ...

  14. Short-term and medium-term outcomes of transapical aortic valve implantation as a single-strategy approach: one center's experience

    PubMed Central

    Mokr?ek, Ale; Pel, Ladislav; Kurfirst, Vojt?ch; ulda, Mirek

    2015-01-01

    Introduction Transcatheter aortic valve replacement has been developed as an alternative option for surgical high-risk or inoperable patients with severe symptomatic aortic stenosis. Aim of the study Aim of the study was to evaluate the outcomes of patients undergoing transapical aortic valve replacement as a single-strategy option by a single-center multidisciplinary heart team. Material and methods Between June 2009 and December 2014, 41 patients underwent transapical transcatheter aortic valve implantation (TA-TAVI) at our institution. All patients received Edwards SAPIEN balloon expandable pericardial valves (Edwards Lifesciences, Irvine, CA, USA). Our center followed a clear transapical strategy for all patients. Results The mean age of the patients was 79.6 years, and the mean logistic EuroSCORE was 21.06 12.82%. Fifteen patients (36.6%) underwent redo operations. Complications included stroke (n = 1), re-exploration for bleeding or cardiac tamponade (n = 4), renal failure requiring temporary hemodialysis (n = 4) and permanent pacemaker implantation (n = 3). There were no myocardial infarctions or coronary obstruction. The total 30-day mortality rate was 17.1% (7 patients). Postoperative intensive care unit stay was 4.6 5.7 days, and mean hospitalization was 11.6 7.2 days. Conclusions The TA-TAVI approach provides good results in terms of early and midterm outcomes. This approach is feasible and safe for patients who have high surgical risk. PMID:26336490

  15. 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)

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

    2013-11-01

    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. For interpretation of color in Fig. 6, the reader is referred to the web version of this article.

  16. An automatic and effective tooth isolation method for dental radiographs

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  17. Long-term stability of soft tissues following alveolar ridge preservation: 10-year results of a prospective study around nonsubmerged implants.

    PubMed

    Roccuzzo, Mario; Gaudioso, Luigi; Bunino, Marco; Dalmasso, Paola

    2014-01-01

    The purpose of this study was to evaluate the long-term clinical outcomes around implants placed in sites previously augmented with demineralized bovine bone mineral with 10% collagen (Bio-Oss Collagen, Geistlich). In this prospective study, 36 consecutive, healthy patients, in need of a single-tooth extraction (incisors, canines, and premolars) and implant replacement, were included. After tooth extraction, Bio-Oss Collagen was inserted in the socket and covered either with a double layer of collagen membrane (test) or with a few drops of a flowable polylactide polymer (control). Following a healing period of 4 to 6 months, a single nonsubmerged implant surgery was performed. After cementation of a single ceramic crown, patients were asked to follow an individualized supportive periodontal therapy program. Clinical and radiographic data were obtained after prosthesis delivery (baseline) and at the 10-year follow-up visit. At the 10-year examination, two patients were lost to follow-up. All implants demonstrated healthy peri-implant soft tissues as documented by standard parameters (full-mouth plaque score, full-mouth bleeding score, local bleeding on probing) in both groups. Mean soft tissue recession (REC) was 0.39 0.54 mm for the test group and 0.50 0.33 mm for the control, with no significant difference between the two groups. The results of this prospective study confirmed the long-term stability of the peri-implant marginal soft tissues supported by regenerated bone by means of the described technique using Bio-Oss Collagen. If the patient is properly followed throughout time, the risk for mucosal recession is low, with < 1 mm of mean REC after 10 years. PMID:25411735

  18. Zirconia Implants in Esthetic Areas: 4-Year Follow-Up Evaluation Study

    PubMed Central

    Borgonovo, Andrea Enrico; Censi, Rachele; Vavassori, Virna; Arnaboldi, Oscar; Maiorana, Carlo

    2015-01-01

    Objectives. The aim is to evaluate the survival and success rates, as well as the marginal bone loss (MBL) and periodontal indexes of zirconia implants positioned in the esthetic jaw areas. Materials and Method. 13 patients were selected and 20 one-piece zirconia implants were used for the rehabilitation of single tooth or partially edentulous ridge in the esthetic jaw areas. Six months after surgery and then once a year, a clinical-radiographic evaluation was performed in order to estimate peri-implant tissue health and marginal bone loss. Results. The survival and success rates were 100%. The average marginal bone loss from baseline to 48 months after surgery was +2.1?mm. Four years after surgery, the median and the mode for visible Plaque Index and Bleeding On Probing resulted 1 whereas Probing Pocket Depth amounted to 3?mm (SD = 0.49?mm). Conclusion. One-piece zirconia dental implants are characterized by high biocompatibility, low plaque adhesion, and absence of microgap that can be related to the clinical success of these implants even in the esthetic areas. PMID:26124836

  19. Totally implantable venous access port systems and associated complications: A single-institution retrospective analysis of 2,996 breast cancer patients

    PubMed Central

    MA, LI; LIU, YUEPING; WANG, JIANXIN; CHANG, YUAN; YU, LONG; GENG, CUIZHI

    2016-01-01

    Totally implantable venous access port systems (TIVAPS) are widely used in breast cancer patients. However, complications are frequent and may necessitate device replacement or removal, resulting in additional patient stress and treatment delays. The aim of this study was to investigate possible risk factors for complications. A total of 2,996 consecutive female breast cancer patients, with a median age of 50.2 years (range, 21.2–85.5 years) were enrolled in this observational, single-centre study between December, 2008 and April, 2014. TIVAPS implantation was principally performed using local anaesthesia and the blind puncture or Seldinger technique through internal jugular or subclavian vein access. A retrospective chart review was conducted to obtain information associated with TIVAPS and patient data. Insertion performed by blind puncture and Seldinger technique had a success ratio of 96.34 and 99.80%, respectively (χ2=29.905, P<0.001). However, the success ratio of the puncture technique group was 99.76% when the TIVAPS was implanted in the right internal jugular vein. The most common complications were late complications, with an overall incidence rate of 5.41% (162/2,996) during the entire device duration. The most common late complications included fibrin formation (1.84%, 55/2,996), port-related bacteraemia (1.44%, 43/2,996) and deep vein thrombosis (0.63%, 19/2,996). No patient died during the study. Our results demonstrated that insertion of TIVAPS by blind puncture or the Seldinger technique through internal jugular or subclavian vein access is convenient, and insertion by the Seldinger technique through the right internal jugular vein is the preferred method. Therefore, TIVAPS is safe for continuous infusional chemotherapy regimens for breast cancer patients.

  20. Comparison of Long-term Survival of Implants and Endodontically Treated Teeth

    PubMed Central

    Setzer, F.C.; Kim, S.

    2014-01-01

    The outcomes of both dental implants and endodontically treated teeth have been extensively studied. However, there is still a great controversy over when to keep a natural tooth and when to extract it for a dental implant. This article reviews the benefits and disadvantages of both treatment options and discusses success vs. survival outcomes, as well as the impact of technical advances for modern endodontics and endodontic microsurgery on the long-term prognosis of tooth retention. PMID:24065635

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

    PubMed Central

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

    2014-01-01

    Background: The aim of this study is to evaluate and compare the crestal bone loss and stability of single mandibular posterior dental implants placed in immediate functional loading (IFL) and immediate nonfunctional loading (INFL) during 6 months after placement. Materials and Methods: Forty single piece root form titanium implants were placed in 20 patients using IFL and INFL techniques. The change in the level of crestal bone was measured on standardized digital periapical radiographs using SOPRO imaging software and stability of implants using resonance frequency analyser taken at the baseline, 1, 3, and 6 months. The measurements were statistically analyzed using the independent and paired t-test (P < 0.05, statistically significant). Results: The mean change in the crestal bone level from baseline to 6 months was significant in both techniques. The implant stability quotient (ISQ) values at first and third months were lower than those at the baseline for both the groups. However, the ISQ values at the sixth month were similar to baseline for both the groups. The crestal bone changes and the ISQ values when compared between the groups showed no statistically significant difference. Conclusion: IFL of dental implants have equivalent results and success rate as that of immediately provisionalized implants within the limitations of this study. PMID:25426151

  2. Skeletal muscle and glioma oxygenation by carbogen inhalation in rats: a longitudinal study by EPR oximetry using single-probe implantable oxygen sensors.

    PubMed

    Hou, Huagang; Khan, Nadeem; Lariviere, Jean; Hodge, Sassan; Chen, Eunice Y; Jarvis, Lesley A; Eastman, Alan; Williams, Benjamin B; Kuppusamy, Periannan; Swartz, Harold M

    2014-01-01

    The feasibility of EPR oximetry using a single-probe implantable oxygen sensor (ImOS) was tested for repeated measurement of pO? in skeletal muscle and ectopic 9L tumors in rats. The ImOS (50 mm length) were constructed using nickel-chromium alloy wires, with lithium phthalocyanine (LiPc, oximetry probe) crystals loaded in the sensor loop and coated with AF 2400() Teflon. These ImOS were implanted into the skeletal muscle in the thigh and subcutaneous 9L tumors. Dynamic changes in tissue pO? were assessed by EPR oximetry at baseline, during tumor growth, and repeated hyperoxygenation with carbogen breathing. The mean skeletal muscle pO? of normal rats was stable and significantly increased during carbogen inhalation in experiments repeated for 12 weeks. The 9L tumors were hypoxic with a tissue pO? of 12.8 6.4 mmHg on day 1; however, the response to carbogen inhalation varied among the animals. A significant increase in the glioma pO? was observed during carbogen inhalation on day 9 and day 14 only. In summary, EPR oximetry with ImOS allowed direct and longitudinal oxygen measurements in deep muscle tissue and tumors. The heterogeneity of 9L tumors in response to carbogen highlights the need to repeatedly monitor pO? to confirm tumor oxygenation so that such changes can be taken into account in planning therapies and interpreting results. PMID:24729220

  3. Biomarkers in orthodontic tooth movement

    PubMed Central

    Kumar, A. Anand; Saravanan, K.; Kohila, K.; Kumar, S. Sathesh

    2015-01-01

    Tooth movement by orthodontic treatment is characterized by remodeling changes in the periodontal ligament, alveolar bone, and gingiva. A reflection of these phenomenons can be found in the gingival crevicular fluid (GCF) of moving teeth, with significant elevations in the concentrations of its components like, cytokines, neurotransmitters, growth Factors, and a arachidonic acid metabolites. GCF arises at the gingival margin and can be described as a transudate or an exudate. Several studies have focused on the composition of GCF and the changes that occur during orthodontic tooth movement (OTM). GCF component analysis is a non-invasive method for studying the cellular response of the underlying periodontium. Clinically, GCF can be easily collected using platinum loops, filter paper strips, gingival washings, and micropipettes. A number of GCF biomarkers involve in bone remodeling during OTM. The data suggest that knowledge of all the biomarkers present in the GCF that can be used to mark the changes in tooth that is undergoing orthodontic treatment may be of clinical usefulness leading to proper choice of mechanical stress to improve and to shorten treatment time and avoid side effects. PMID:26538871

  4. Tooth eruption: theories and facts.

    PubMed

    Marks, S C; Schroeder, H E

    1996-06-01

    The mechanisms of tooth eruption (i.e., the answer to the question of how and why teeth erupt) has been a matter of long historical debate. This review focuses on human and other mammalian teeth with a time- and spacewise limited period of eruption and analyzes recent observations and experimental data on dogs, rats, primates, and humans in a framework of basic biological parameters to formulate a guiding theory of tooth eruption. Acknowledging basic parameters (i.e., that teeth move in three-dimensional space, erupt with varying speed, and arrive at a functional position that in inheritable) eliminates a number of previously held theories and favors those that accommodate basic parameters, such as alveolar bone remodeling in association with root elongation, with possible correction factors in the form of cementum apposition and periodontal ligament formation. We have critically analyzed, summarized, and integrated recent findings associated with preeruptive movements of developing teeth, the intraosseous stage of premolar eruption in dogs, molar eruption in rodents, and premolar and molar eruption in primates. The variable speeds of eruption are particularly important. We conclude with basic principles of tooth eruption--that is, the type of signals generated by the dental follicle proper, the conditions under which teeth are moved and the clinical understanding to be derived from this knowledge. PMID:8769674

  5. Modification of osseointegrated implants for distal-extension prostheses.

    PubMed

    el Charkawi, H G; el Wakad, M T; Naser, M E

    1990-10-01

    The use of a distal implant abutment splinted to a natural tooth by a fixed partial denture has been employed for distal-extension prostheses. There is a differential difference between the viscoelastic deflection of a natural tooth by its periodontal ligament, and the almost negligible elastic deformation of an osseointegrated implant. This difference may induce a fulcrum-like effect and overstress the implant. In this study a new modification of osseointegrated implants was proposed to counteract this problem. This modification was achieved by using a resilient layer material under the superstructure of the implant. Finite element modeling (FEM) was used to examine stresses and displacement distribution around a commercially available implant and one experimental implant with a resilient layer material. The results of this study showed that the new modification is a simple and efficient way to mimic the structural natural tooth unit. It also showed that it allowed movement of the superstructure without movement of the implant three times that of the nonresilient model. PMID:2231458

  6. Intermediate-Term Results of 142 Single-Design, Rotating-Hinge Implants: Frequent Complications May Not Preclude Salvage of Severely Affected Knees.

    PubMed

    Farid, Yasser R; Thakral, Rishi; Finn, Henry A

    2015-12-01

    Rotating-hinge knee prostheses have low survivorship and high complications except in primary arthroplasties in elderly patients. We retrospectively reviewed 142 single third-generation design, rotating hinge prostheses (11 primary procedures and 131 revisions) at 57months follow up. Implant survival was 73 %. Successful two-stage reimplantation for prosthetic infection was 78.4% but new infection rate was 22%. The tibial component was durable while the femoral component was problematic. We observed only one patellar maltracking and no polyethylene wear. A third generation rotating-hinge arthroplasty reconstruction was reliable in complex problems. Outcomes in primary situations were excellent. Complications were the rule rather than the exception in revisions. With timely intervention, attention to soft tissue coverage, and realistic expectations, complications were contained and functional benefits were appreciable. PMID:26169452

  7. Consideration of Moving Tooth Load in Gear Crack Propagation Predictions

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Handschuh, Robert F.; Spievak, Lisa E.; Wawrzynek, Paul A.; Ingraffea, Anthony R.

    2001-01-01

    Robust gear designs consider not only crack initiation, but crack propagation trajectories for a fail-safe design. In actual gear operation, the magnitude as well as the position of the force changes as the gear rotates through the mesh. A study to determine the effect of moving gear tooth load on crack propagation predictions was performed. Two-dimensional analysis of an involute spur gear and three-dimensional analysis of a spiral-bevel pinion gear using the finite element method and boundary element method were studied and compared to experiments. A modified theory for predicting gear crack propagation paths based on the criteria of Erdogan and Sih was investigated. Crack simulation based on calculated stress intensity factors and mixed mode crack angle prediction techniques using a simple static analysis in which the tooth load was located at the highest point of single tooth contact was validated. For three-dimensional analysis, however, the analysis was valid only as long as the crack did not approach the contact region on the tooth.

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

    SciTech Connect

    Sato, Morio Mori, Takashi; Shirai, Shintaro; Kishi, Kazushi; Inagaki, Takeshi; Hara, Isao

    2008-11-15

    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.

  9. Tapered implants: from indications to advantages.

    PubMed

    Alves, Clia Coutinho; Neves, Manuel

    2009-04-01

    Tapered implants have become routine for immediate implant placement after tooth extraction. It seemed extremely advantageous to use tapered implants in type 4 bone, where primary stability is difficult to achieve. The authors established a surgical implant placement protocol to be followed in areas where type 4 bone and a wide bone ridge (> or = 8 mm) are present. First, preparation of the implant alveolus is done exclusively with cylindric osteotomes, rather than with conic osteotomes or drills. The final cylindric osteotome is the same diameter as the final twist drill that is typically used in conventional preparation of the implant alveolus (a technique that can be adapted for use with other tapered implants). Because of the self-tapping property of the tapered implant used and its anatomic design, this surgical technique was developed to optimize the bone compaction effect in the coronal third of the implant, improving bone density and providing better primary stability values (> or = 70 ISO, via the Osstell Mentor device). With the strong bond that is created between the implant surface and the surrounding bone using this technique, immediate loading can be predictable, even in the type 4 bone that is commonly found in the maxillary tuberosity. PMID:19408478

  10. Development and demonstration of a two-dimensional, accurate and computationally-efficient model for boron implantation into single-crystal silicon through overlying oxide layers

    SciTech Connect

    Morris, S.; Lim, D.; Yang, S.H.; Tian, S.; Parab, K.; Tasch, A.F.

    1996-12-31

    A 2-D model for boron implantation into (100) silicon through overlying oxide layers has been developed and implemented into the process simulator FLOOPS. This model is both accurate and computationally efficient and shows explicit dependencies on all of the key implant parameters: energy, dose, tilt and rotation angles, oxide layer thickness, mask height, mask edge orientation, and rotation of the wafer during implantation.

  11. Surface modifications of dental implants.

    PubMed

    Stanford, C M

    2008-06-01

    Dental implant surface technologies have been evolving rapidly to enhance a more rapid bone formation on their surface and hold a potential to increase the predictability of expedited implant therapy. While implant outcomes have become highly predictable, there are sites and conditions that result in elevated implant loss. This paper reviews the impact of macro-retentive features which includes approaches to surface oxide modification, thread design, press-fit and sintered-bead technologies to increase predictability of outcomes. Implant designs that lead to controlled lateral compression of the bone can improve primary stability as long as the stress does not exceed the localized yield strength of the cortical bone. Some implant designs have reduced crestal bone loss by use of multiple cutting threads that are closely spaced, smoothed on the tip but designed to create a hoop-stress stability of the implant as it is completely seated in the osteotomy. Following the placement of the implant, there is a predictable sequence of bone turnover and replacement at the interface that allows the newly formed bone to adapt to microscopic roughness on the implant surface, and on some surfaces, a nanotopography (<10(-9) m scale) that has been shown to preferably influence the formation of bone. Newly emerging studies show that bone cells are exquisitely sensitive to these topographical features and will upregulate the expression of bone related genes for new bone formation when grown on these surfaces. We live in an exciting time of rapid changes in the modalities we can offer patients for tooth replacement therapy. Given this, it is our responsibility to be critical when claims are made, incorporate into our practice what is proven and worthwhile, and to continue to support and provide the best patient care possible. PMID:18498581

  12. Implant-supported prostheses esthetic outcomes after socket preservation technique.

    PubMed

    Perelli, Michele; Abundo, Roberto; Corrente, Giuseppe; Saccone, Carlo; Zambelli, Marta

    2015-05-01

    Bone and soft tissue remodeling after tooth extraction may have dramatic effects. The socket preservation technique has demonstrated to be effective in maintaining volume before implant placement. The Pink Esthetic Score (PES) is an easy and complete evaluation of esthetic parameters. The aim of this study was to compare the PES index of anterior teeth needing to be replaced and the correspondent implant-supported prostheses after the socket preservation technique with 1 year of follow-up. Twenty-four patients were enrolled in this study. Eighteen maxillary central incisors and 6 maxillary lateral incisors were extracted, and then, every alveolar site was treated with the socket preservation technique and filled with Bio-Oss, mixed with fibrin glue, and covered with a collagen sponge. After 6 months of undisturbed healing, implants were placed and left healing for 4 months. After they were regularly loaded and at 1 year of follow-up, peri-implant PESs were recorded. All implants integrated successfully. No dropouts were recorded. Comparing PES results before extraction (mean, 12.25) and after implant loading (mean, 12.35), those around implants are similar if not better, and there are no statistically significant differences as analyzed with the t-test. The socket preservation technique combined with delayed implant placement and a standard healing time before implant loading has demonstrated to be effective in maintaining volumes and also esthetic values around implants compared with PES values before tooth extraction. PMID:25974780

  13. Cochlear Implants

    MedlinePLUS

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

  14. Cochlear Implants

    MedlinePLUS

    ... newsroom@entnet.org . A cochlear implant is an electronic device that restores partial hearing to individuals with ... An internal component that consists of a small electronic device that is surgically implanted under the skin ...

  15. Cochlear Implants

    MedlinePLUS

    ... children receive a cochlear implant followed by intensive therapy before 18 months of age, they are better able to hear, comprehend sound and music, and speak than their peers who receive implants ...

  16. Charcot–Marie–Tooth disease

    PubMed Central

    Szigeti, Kinga; Lupski, James R

    2009-01-01

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

  17. Long-Term Outcomes After Transcatheter Aortic Valve Implantation from a Single High-Volume Center (The Milan Experience).

    PubMed

    Ruparelia, Neil; Latib, Azeem; Buzzatti, Nicola; Giannini, Francesco; Figini, Filippo; Mangieri, Antonio; Regazzoli, Damiano; Stella, Stefano; Sticchi, Alessandro; Kawamoto, Hiroyoshi; Tanaka, Akihito; Agricola, Eustachio; Monaco, Fabrizio; Castiglioni, Alessandro; Ancona, Marco; Cioni, Micaela; Spagnolo, Pietro; Chieffo, Alaide; Montorfano, Matteo; Alfieri, Ottavio; Colombo, Antonio

    2016-03-01

    Transcatheter aortic valve implantation (TAVI) is now the treatment of choice for patients with symptomatic aortic stenosis who are inoperable or with high surgical risk. Data with regards to contemporary clinical practice and long-term outcomes are sparse. To evaluate temporal changes in TAVI practice and explore procedural and long-term clinical outcomes of patients in a contemporary "real-world" population, outcomes of 829 patients treated from November 2007 to May 2015, at the San Raffaele Scientific Institute, Milan, Italy, were retrospectively analyzed. Median follow-up was 568days, with the longest follow-up of 2,677days. Overall inhospital mortality was 3.5%. During the study period, there was a trend toward treating younger, lower risk patients. Overall mortality rates were 3.5% (30days), 14% (1year), 22% (2years), 29% (3years), 37% (4years), 47% (5years), 53% (6years), and 72% (7years). The survival probability at 5years was significantly higher in patients treated through the transfemoral (TF) route compared to other vascular access sites (log rank p <0.001). Non-TF vascular access and residual paravalvular leak ?2 (after TAVI) were identified as independent predictors for both all-cause and cardiovascular mortality. No patient required further aortic valve intervention for TAVI prosthesis degeneration. In conclusion, there is a trend toward treating younger, lower-risk patients. Non-TF vascular access approach and ?2 PVL after TAVI were identified as independent predictors for both overall and cardiovascular mortality with no cases of prosthesis degeneration suggesting acceptable durability. PMID:26742477

  18. Management of Grade III Mobile Anterior Tooth in Function Using Endostabilizer A Case Report

    PubMed Central

    Patil, Swapnil N

    2014-01-01

    Impact of implant dentistry is such that today very few dentists think about saving grade III mobile anterior teeth. A patient with grade III mobility of central incisor due to apical root resorption was treated by using 80 no.stainless steel H file as endostabiliser and one year follow up was done. Endostabiliser reduced the mobility of grade III mobile teeth drastically, immediately after its placement. Tooth was absolutely asymptomatic throughout one year follow up. PMID:25654043

  19. Cochlear implants in China.

    PubMed

    Zeng, F G

    1995-01-01

    China has approximately 6 million totally deaf people according to an official survey conducted in 1990, although the actual number is probably higher. A primary cause of deafness is the use of ototoxic drugs. There does not appear to be any emergent deaf culture in China at present. As the only available medical device that can restore partial hearing to a totally deaf person, the cochlear implant has been in development in China since 1979. This paper provides an overview of cochlear implants in China and is based on a review of published materials, visits to research institutes and hospitals, and personal communication with Chinese colleagues. As of 1993, about 1,000 deaf people, including 50 children below age 12 years, have received four types of single-electrode cochlear implants that were developed and fabricated by institutions in China. These single-electrode devices have provided an aid to lip reading, but are no longer in use due to their inability to produce open-set speech recognition. Present implant research in China focuses on development of multi-electrode devices. Basic research in electrical stimulation is relatively lacking and standardized audiological evaluation for cochlear implant effectiveness needs to be developed. The present economic growth and legal system reform in China, combined with advances in implant technology, may make it possible to produce an affordable yet effective cochlear implant system. This paper discusses cochlear implants only in China, but the social and economic factors are similar in many developing countries in Asia, South America, Eastern Europe, and Africa, where a low-cost, high-performance cochlear implant system is also needed. PMID:8561684

  20. Human Umbilical Cord Mesenchymal Stem Cells: A New Therapeutic Option for Tooth Regeneration

    PubMed Central

    Chen, Yuanwei; Yu, Yongchun; Chen, Lin; Ye, Lanfeng; Cui, Junhui; Sun, Quan; Li, Kaide; Li, Zhiyong; Liu, Lei

    2015-01-01

    Tooth regeneration is considered to be an optimistic approach to replace current treatments for tooth loss. It is important to determine the most suitable seed cells for tooth regeneration. Recently, human umbilical cord mesenchymal stem cells (hUCMSCs) have been regarded as a promising candidate for tissue regeneration. However, it has not been reported whether hUCMSCs can be employed in tooth regeneration. Here, we report that hUCMSCs can be induced into odontoblast-like cells in vitro and in vivo. Induced hUCMSCs expressed dentin-related proteins including dentin sialoprotein (DSP) and dentin matrix protein-1 (DMP-1), and their gene expression levels were similar to those in native pulp tissue cells. Moreover, DSP- and DMP-1-positive calcifications were observed after implantation of hUCMSCs in vivo. These findings reveal that hUCMSCs have an odontogenic differentiation potency to differentiate to odontoblast-like cells with characteristic deposition of dentin-like matrix in vivo. This study clearly demonstrates hUCMSCs as an alternative therapeutic cell source for tooth regeneration. PMID:26136785

  1. X-ray standing wave and ion scattering studies on Au-implanted LiNbO 3(0001) single crystals

    NASA Astrophysics Data System (ADS)

    Dev, B. N.; Kuri, G.; Satyam, P. V.; Sundaravel, B.; Gog, Th.; Materlik, G.

    1998-02-01

    X-ray standing wave and combined Rutherford backscattering spectrometry and channeling experiments have been performed on Au-implanted and annealed (0001)-oriented LiNbO 3 single crystals. At an ion dose of ? 1 10 15 cm -2 confined in a 117 nm thick (FWHM) layer, resulting in a Au/Nb ratio of ? 5 10 -3, no significant cluster formation has been observed. Most of the Au atoms have been found to lie on the c-axis of the LiNbO 3 structure. However, they do not occupy a single lattice site. Rather they appear to be distributed over several sites on the [0001] atomic strings, which contain Nb, Li and structural vacancy sites. A small fraction ( ca. 20%) of the Au atoms appear to be displaced from the threefold symmetry axis - most likely at tetrahedral sites. The possibility of this fraction of Au atoms existing as small clusters like dimers or trimers cannot be ruled out.

  2. Immunomodulation Stimulates the Innervation of Engineered Tooth Organ

    PubMed Central

    Kkten, Tunay; Bcavin, Thibault; Keller, Laetitia; Weickert, Jean-Luc; Kuchler-Bopp, Sabine; Lesot, Herv

    2014-01-01

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

  3. Immunomodulation stimulates the innervation of engineered tooth organ.

    PubMed

    Kkten, Tunay; Bcavin, Thibault; Keller, Laetitia; Weickert, Jean-Luc; Kuchler-Bopp, Sabine; Lesot, Herv

    2014-01-01

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

  4. A simple rule governs the evolution and development of hominin tooth size.

    PubMed

    Evans, Alistair R; Daly, E Susanne; Catlett, Kierstin K; Paul, Kathleen S; King, Stephen J; Skinner, Matthew M; Nesse, Hans P; Hublin, Jean-Jacques; Townsend, Grant C; Schwartz, Gary T; Jernvall, Jukka

    2016-02-25

    The variation in molar tooth size in humans and our closest relatives (hominins) has strongly influenced our view of human evolution. The reduction in overall size and disproportionate decrease in third molar size have been noted for over a century, and have been attributed to reduced selection for large dentitions owing to changes in diet or the acquisition of cooking. The systematic pattern of size variation along the tooth row has been described as a 'morphogenetic gradient' in mammal, and more specifically hominin, teeth since Butler and Dahlberg. However, the underlying controls of tooth size have not been well understood, with hypotheses ranging from morphogenetic fields to the clone theory. In this study we address the following question: are there rules that govern how hominin tooth size evolves? Here we propose that the inhibitory cascade, an activator-inhibitor mechanism that affects relative tooth size in mammals, produces the default pattern of tooth sizes for all lower primary postcanine teeth (deciduous premolars and permanent molars) in hominins. This configuration is also equivalent to a morphogenetic gradient, finally pointing to a mechanism that can generate this gradient. The pattern of tooth size remains constant with absolute size in australopiths (including Ardipithecus, Australopithecus and Paranthropus). However, in species of Homo, including modern humans, there is a tight link between tooth proportions and absolute size such that a single developmental parameter can explain both the relative and absolute sizes of primary postcanine teeth. On the basis of the relationship of inhibitory cascade patterning with size, we can use the size at one tooth position to predict the sizes of the remaining four primary postcanine teeth in the row for hominins. Our study provides a development-based expectation to examine the evolution of the unique proportions of human teeth. PMID:26911784

  5. Tooth shape formation and tooth renewal: evolving with the same signals.

    PubMed

    Jernvall, Jukka; Thesleff, Irma

    2012-10-01

    Teeth are found in almost all vertebrates, and they therefore provide a general paradigm for the study of epithelial organ development and evolution. Here, we review the developmental mechanisms underlying changes in tooth complexity and tooth renewal during evolution, focusing on recent studies of fish, reptiles and mammals. Mammals differ from other living vertebrates in that they have the most complex teeth with restricted capacity for tooth renewal. As we discuss, however, limited tooth replacement in mammals has been compensated for in some taxa by the evolution of continuously growing teeth, the development of which appears to reuse the regulatory pathways of tooth replacement. PMID:22949612

  6. Periodontio-integrated implants: A revolutionary concept.

    PubMed

    Gulati, Minkle; Anand, Vishal; Govila, Vivek; Jain, Nikil; Rastogi, Pavitra; Bahuguna, Rohit; Anand, Bhargavi

    2014-03-01

    Though the fields of regenerative dentistry and tissue engineering have undergone significant advancements, yet its application to the field of implant-dentistry is lacking; in the sense that presently the implants are being placed with the aim of attaining osseointegration without giving consideration to the regeneration of periodontium around the implant. The following article reveals the clinical benefits of such periodontio-integrated implants and reviews the relevant scientific proofs. A comprehensive research to provide scientific evidence supporting the feasibility of periodontio-integrated implants was carried out using various online resources such as PubMed, Wiley-Blackwell, Elsevier etc., to retrieve studies published between 1980 and 2012 using the following key words: "implant," "tissue engineering," "periodontium," "osseo-integration," "osseoperception," "regeneration" (and their synonyms) and it was found that in the past three decades, several successful experiments have been conducted to devise "implant supported by the periodontium"that can maintain form, function and potential proprioceptive responses similar to a natural tooth. Based on these staunch evidences, the possibility of the future clinical use of such implant can be strongly stated which would revolutionize the implant dentistry and will be favored by the patients as well. However, further studies are required to validate the same. PMID:24932184

  7. Periodontio-integrated implants: A revolutionary concept

    PubMed Central

    Gulati, Minkle; Anand, Vishal; Govila, Vivek; Jain, Nikil; Rastogi, Pavitra; Bahuguna, Rohit; Anand, Bhargavi

    2014-01-01

    Though the fields of regenerative dentistry and tissue engineering have undergone significant advancements, yet its application to the field of implant-dentistry is lacking; in the sense that presently the implants are being placed with the aim of attaining osseointegration without giving consideration to the regeneration of periodontium around the implant. The following article reveals the clinical benefits of such periodontio-integrated implants and reviews the relevant scientific proofs. A comprehensive research to provide scientific evidence supporting the feasibility of periodontio-integrated implants was carried out using various online resources such as PubMed, Wiley-Blackwell, Elsevier etc., to retrieve studies published between 1980 and 2012 using the following key words: implant, tissue engineering, periodontium, osseo-integration, osseoperception, regeneration (and their synonyms) and it was found that in the past three decades, several successful experiments have been conducted to devise implant supported by the periodontiumthat can maintain form, function and potential proprioceptive responses similar to a natural tooth. Based on these staunch evidences, the possibility of the future clinical use of such implant can be strongly stated which would revolutionize the implant dentistry and will be favored by the patients as well. However, further studies are required to validate the same. PMID:24932184

  8. Implant stability comparison of immediate and delayed maxillary implant placement by use of resonance frequency analysis--a clinical study.

    PubMed

    Grani?, Marko; Katanec, Davor; Vu?i?evi? Boras, Vanja; Sui?, Mato; Juri?, Ivona Bago; Gabri?, Dragana

    2015-03-01

    The purpose of this study was to objectively evaluate the stability of dental implants by use of resonance frequency analysis (RFA). In this study, 60 Nobel Replace Tapered Groovy implants were placed in the premolar region of the maxilla in 60 patients. Thirty implants were placed immediately after tooth extraction and 30 implants were placed in healed bone sites. Implant stability quotient (ISQ) was obtained by use of the Osstell Mentor device and was recorded at the time of implant placement (T1) and 20 weeks after placement, at the time of implant loading (T2). All implants were not functionally loaded during the follow up period. Data were analyzed using simple linear regression. No implant failures were reported in the 6-month follow up period. The mean ISQvalue for immediate implant placement was 61.43 at T1 and 66.23 at T2. The implants placed in healed bone showed higher ISQvalues compared to the immediately placed implants (mean ISQvalue was 64.17 at T1 and 68.83 at T2). Differences in the mean ISQ values were statistically significant (p < 0.001). After the completed period of osseointegration, the mean ISQ value was 4.8 for immediately placed implants compared to 4.67 for implants placed in delayed sites. PMID:26058235

  9. [Tooth erosion - a multidisciplinary approach].

    PubMed

    Strużycka, Izabela; Rusyan, Ewa; Bogusławska-Kapała, Agnieszka

    2016-02-01

    During the last decades, an increasingly greater interest in dental erosion has been observed in clinical dental practice, in dental public health and in dental research because prevalence of erosive tooth wear is still increasing especially in young age group of population. Erosive tooth wear is a multifactorial etiology process characterized by progressive loss of hard dental tissue. It is defined as the exogenous and/or endogenous acids dissolution of the dental tissue, without bacterial involvement. In the development of dental erosive wear , interactions are required which include chemical, biological, behavioral, diet, time, socioeconomic, knowledge, education, and general health factors. Examples of risk groups could be patients with eating disorders, like anorexia nervosa or bulimia nervosa, gastroesophageal reflux disease, chronic alcohol abuse or dependence. Special nutrition habits groups with high consumption of soft or sport drinks, special diets like vegetarian, vegan or raw food diet, the regular intake of drugs, medications and food supplements can also increase the risk for dental erosion. Comprehensive knowledge of the different risk and protective factors is a perquisite for initiating adequate preventive measures. PMID:27000809

  10. Charcot-Marie-Tooth disease

    PubMed Central

    Sivera, Rafael; Vílchez, Juan Jesús; Martínez-Rubio, Dolores; Chumillas, María José; Vázquez, Juan Francisco; Muelas, Nuria; Bataller, Luis; Millán, José María; Palau, Fancesc; Espinós, Carmen

    2013-01-01

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

  11. Automating Digital Leaf Measurement: The Tooth, the Whole Tooth, and Nothing but the Tooth

    PubMed Central

    Corney, David P. A.; Tang, H. Lilian; Clark, Jonathan Y.; Hu, Yin; Jin, Jing

    2012-01-01

    Many species of plants produce leaves with distinct teeth around their margins. The presence and nature of these teeth can often help botanists to identify species. Moreover, it has long been known that more species native to colder regions have teeth than species native to warmer regions. It has therefore been suggested that fossilized remains of leaves can be used as a proxy for ancient climate reconstruction. Similar studies on living plants can help our understanding of the relationships. The required analysis of leaves typically involves considerable manual effort, which in practice limits the number of leaves that are analyzed, potentially reducing the power of the results. In this work, we describe a novel algorithm to automate the marginal tooth analysis of leaves found in digital images. We demonstrate our methods on a large set of images of whole herbarium specimens collected from Tilia trees (also known as lime, linden or basswood). We chose the genus Tilia as its constituent species have toothed leaves of varied size and shape. In a previous study we extracted leaves automatically from a set of images. Our new algorithm locates teeth on the margins of such leaves and extracts features such as each tooth’s area, perimeter and internal angles, as well as counting them. We evaluate an implementation of our algorithm’s performance against a manually analyzed subset of the images. We found that the algorithm achieves an accuracy of 85% for counting teeth and 75% for estimating tooth area. We also demonstrate that the automatically extracted features are sufficient to identify different species of Tilia using a simple linear discriminant analysis, and that the features relating to teeth are the most useful. PMID:22870286

  12. Cognitive function after transapical aortic valve implantation: a single-centre study with 3-month follow-up

    PubMed Central

    Knipp, Stephan C.; Kahlert, Philipp; Jokisch, Daniel; Schlamann, Marc; Wendt, Daniel; Weimar, Christian; Jakob, Heinz; Thielmann, Matthias

    2013-01-01

    OBJECTIVES Reports on adverse neurological events following transcatheter aortic valve implantation (TAVI) have focused on strokes, while more subtle postoperative cognitive decline has not yet been systematically investigated. In this study, we prospectively examined neurological and cognitive outcomes in patients undergoing transapical (TA) and surgical aortic valve replacement (AVR). METHODS A total of 64 patients with severe symptomatic aortic stenosis were investigated between January 2008 and July 2009. Clinical neurological examination and comprehensive neuropsychological testing were performed before and after the procedure, at discharge and at 3-month follow-up. Diffusion-weighted magnetic resonance imaging (DW-MRI) was applied to detect morphological brain injury. RESULTS TA-TAVI patients (n = 27) were older and at higher surgical risk compared with surgical AVR patients (n = 37; mean age 82.2 4.7 vs 67.5 8.9 years; log EuroSCORE 36.4 13.2 vs 2.6 8.5%, both P <0.001). There was one stroke in each group (3.7 vs 2.7%, P = 0.49), both classified as embolic based on imaging characteristics. After TA-TAVI, cognitive tests showed no decline during follow-up, while, after AVR, 7 of 11 tests showed a decline early after surgery. Similarly, with-in patient analysis showed that the rate of individuals with clinically relevant cognitive decline was increased early after AVR (TA-TAVI vs AVR: 18 vs 46% at discharge [P = 0.03]; 28 vs 6% at 3 months [P = 0.04]). New focal ischaemic cerebral lesions were detected on DW-MRI in 58% (7 of 12) of patients after TA-TAVI vs 34% (12 of 35) after AVR (P = 0.13). The number of brain lesions per patient and cumulative embolic load per patient were similar between groups. An association between postoperative cerebral ischaemia and cognitive dysfunction was not found (odds ratio 2.37, 95% confidence interval 0.05113.75, P = 0.66). CONCLUSIONS Cognitive function was only mildly impaired after TA-TAVI when compared with a marked, albeit transient, decline after surgical AVR. Focal embolic brain injury tended to occur more frequently after TA-TAVI, but this was not related to cognitive decline during the 3-month follow-up. PMID:23148084

  13. Addressing Tooth Decay in Head Start Children

    ERIC Educational Resources Information Center

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

    2012-01-01

    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

  14. Investigation of EPR signals on tooth enamel

    NASA Astrophysics Data System (ADS)

    Pavlenko, A.; Mironova-Ulmane, N.; Polakov, M.; Riekstina, D.

    2007-12-01

    Calcified tissues are involved in continues metabolic process in human organism exchanging a number of chemical elements with environment. The rate of biochemical reactions is tissue dependent and the slowest one at the tooth enamel, the most mineralized tissue of human organism. The long time stability and unique chemical composition make tooth enamel suitable for number of application. The assessment of individual radiation dose by Electron Paramagnetic Resonance (EPR) and evaluations of elemental composition by Instrumentation Neutron Activation Analysis (INAA) are the well known procedures where properties of tooth enamel intensively used. The current work is focused on investigation of EPR signals and determination of chemical composition on several teeth samples having different origin. The EPR spectra and INAA element content of milk tooth, caries tooth, and paradantose tooth have been compared to each other. The results showed that the intensity of EPR signal is much higher for the caries tooth than the for paradantose tooth that is in agreement with depleted Ca content.

  15. Addressing Tooth Decay in Head Start Children

    ERIC Educational Resources Information Center

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

    2012-01-01

    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…

  16. Tooth Whitening: What We Now Know

    PubMed Central

    Carey, Clifton M.

    2014-01-01

    Declarative Title Current research about tooth whitening shows that it is safe and effective when manufacturers protocol is followed, yet there are risks of which the profession and users should be aware. This update provides a summary of current research and assessment of the safety and efficacy of tooth whitening regimens. Background Tooth whitening has become one of the most frequently requested dental procedures by the public. The public has come to demand whiter, more perfect smiles and in response many choices for tooth whitening have been made available. These include home-based products such as toothpastes, gels, and films, as well as in-office based systems where products containing highly concentrated bleaching agents are applied under professional supervision. The profession and public have been aware of certain risks related to tooth whitening such as increased tooth sensitivity and gingival irritation. New research has shown that there are other risks such as tooth surface roughening and softening, increased potential for demineralization, degradation of dental restorations, and unacceptable color change of dental restorations. The new research is also focused on optimizing whitening procedures to reduce tooth sensitivity and to increase the persistence of the whitening. Methods Current reports in the literature are reviewed that are related to the use of peroxide based whitening methods. These reports include in vitro studies for method optimization and mechanism as well as clinical studies on effects of various whitening regimens. Conclusions When manufacturers instructions are followed, hydrogen peroxide and carbamide peroxide based tooth whitening is safe and effective. Patients should be informed of the risks associated with tooth whitening and instructed on identification of adverse occurrences so that they may seek professional help asneeded. PMID:24929591

  17. Immediate Implant Placement After Removal of Maxillary Impacted Canine Teeth: A Technical Note.

    PubMed

    Demarosi, Federica; Varoni, Elena; Rimondini, Lia; Carrassi, Antonio; Leghissa, Giulio Cesare

    2016-01-01

    Impacted maxillary canine teeth commonly occur in the general population. The traditional therapeutic approach comprises fenestration and orthodontic traction; however, if traction is not feasible or the patient refuses orthodontic treatment, an alternative solution is to remove the impacted tooth and immediately place an implant. This technical note describes a novel surgical approach to rehabilitation after impacted canine tooth removal, entailing immediate placement of a long implant in combination with regenerative materials and a barrier. Of note, this procedure preserves the apical ridge bone crest, allowing implant anchorage and primary stability to be achieved. PMID:26800178

  18. Ultrasonic assessment of tooth structure

    NASA Astrophysics Data System (ADS)

    Blodgett, David W.

    2002-06-01

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

  19. 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

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

    2009-01-01

    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

  20. Implantable Microimagers

    PubMed Central

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

    2008-01-01

    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.

  1. High Productivity Implantation ''PARTIAL IMPLANT''

    SciTech Connect

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

    2008-11-03

    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.

  2. Endodontic implants.

    PubMed

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

    2014-01-01

    Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities. PMID:25298723

  3. Endodontic implants

    PubMed Central

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

    2014-01-01

    Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities. PMID:25298723

  4. Effect of Bleaching Agents on the Nanohardness of Tooth Enamel, Composite Resin, and the Tooth-Restoration Interface.

    PubMed

    Abe, A T; Youssef, M N; Turbino, M L

    2016-01-01

    This in vitro study aimed to evaluate the nanohardness of tooth enamel, composite resin, dental adhesive, and enamel hybrid layer exposed to 35% hydrogen peroxide-based bleaching agents and analyze the tooth-restoration interface using scanning electron microscopy (SEM). This study used 40 crowns of bovine incisors, which were embedded in epoxy resin. A 2 × 2 × 2-mm cavity was prepared in the medial third of the flattened buccal surface of each tooth and restored (two-step etch-and-rinse Adper Single Bond 2 + nanocomposite resin Filtek Z350 XT). The specimens were polished and divided into four groups (n=10), corresponding to each bleaching agent used (TB: Total Blanc Office, pH=7.22-6.33; HPB: Whiteness HP Blue, pH=8.89-8.85; HP: Whiteness HP, pH=6.65-6.04; PO: Pola Office, pH=3.56-3.8), applied in accordance with manufacturer protocols. The nanohardness of the substrates was measured before and immediately after the bleaching procedure and after 7-day storage in artificial saliva with an Ultra-Microhardness Tester (DUH-211S, Shimadzu). Loads used were 100 mN for tooth enamel and composite resin and 10 mN for adhesive and enamel hybrid layer. For SEM analysis, epoxy replicas were prepared through high-precision impressions of the specimens. For nanohardness, the statistical tests two-way analysis of variance and Tukey (p<0.05) revealed that the agent with the lowest pH value (PO) was the only one to decrease the nanohardness of enamel and the enamel hybrid layer immediately after its application; however, after 7-day storage in artificial saliva, the nanohardness levels of these substrates returned to their original values. SEM analysis revealed small gaps between tooth enamel and adhesive after the exposure to all bleaching agents; however, the most evident gap in the tooth-restoration interface was observed immediately after application of agent PO. No bleaching agent used changed the nanohardness of the composite resin and adhesive layer. PMID:26266649

  5. Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs

    PubMed Central

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

    2013-01-01

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

  6. Regenerative Applications Using Tooth Derived Stem Cells in Other Than Tooth Regeneration: A Literature Review.

    PubMed

    Park, Yun-Jong; Cha, Seunghee; Park, Young-Seok

    2016-01-01

    Tooth derived stem cells or dental stem cells are categorized according to the location from which they are isolated and represent a promising source of cells for regenerative medicine. Originally, as one kind of mesenchymal stem cells, they are considered an alternative of bone marrow stromal cells. They share many commonalties but maintain differences. Considering their original function in development and the homeostasis of tooth structures, many applications of these cells in dentistry have aimed at tooth structure regeneration; however, the application in other than tooth structures has been attempted extensively. The availability from discarded or removed teeth can be an innate benefit as a source of autologous cells. Their origin from the neural crest results in exploitation of neurological and numerous other applications. This review briefly highlights current and future perspectives of the regenerative applications of tooth derived stem cells in areas beyond tooth regeneration. PMID:26798366

  7. Regenerative Applications Using Tooth Derived Stem Cells in Other Than Tooth Regeneration: A Literature Review

    PubMed Central

    Park, Yun-Jong; Cha, Seunghee; Park, Young-Seok

    2016-01-01

    Tooth derived stem cells or dental stem cells are categorized according to the location from which they are isolated and represent a promising source of cells for regenerative medicine. Originally, as one kind of mesenchymal stem cells, they are considered an alternative of bone marrow stromal cells. They share many commonalties but maintain differences. Considering their original function in development and the homeostasis of tooth structures, many applications of these cells in dentistry have aimed at tooth structure regeneration; however, the application in other than tooth structures has been attempted extensively. The availability from discarded or removed teeth can be an innate benefit as a source of autologous cells. Their origin from the neural crest results in exploitation of neurological and numerous other applications. This review briefly highlights current and future perspectives of the regenerative applications of tooth derived stem cells in areas beyond tooth regeneration. PMID:26798366

  8. Biomaterials in Tooth Tissue Engineering: A Review

    PubMed Central

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

    2014-01-01

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

  9. Biomaterials in tooth tissue engineering: a review.

    PubMed

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

    2014-01-01

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

  10. Redo aortic valve surgery versus transcatheter valve-in-valve implantation for failing surgical bioprosthetic valves: consecutive patients in a single-center setting

    PubMed Central

    Wottke, Michael; Deutsch, Marcus-Andr; Krane, Markus; Piazza, Nicolo; Lange, Ruediger; Bleiziffer, Sabine

    2015-01-01

    Background Due to a considerable rise in bioprosthetic as opposed to mechanical valve implantations, an increase of patients presenting with failing bioprosthetic surgical valves in need of a reoperation is to be expected. Redo surgery may pose a high-risk procedure. Transcatheter aortic valve-in-valve implantation is an innovative, less-invasive treatment alternative for these patients. However, a comprehensive evaluation of the outcome of consecutive patients after a valve-in-valve TAVI [transcatheter aortic valve-in-surgical aortic valve (TAV-in-SAV)] as compared to a standard reoperation [surgical aortic valve redo-operation (SAV-in-SAV)] has not yet been performed. The goal of this study was to compare postoperative outcomes after TAV-in-SAV and SAV-in-SAV in a single center setting. Methods All SAV-in-SAV and TAV-in-SAV patients from January 2001 to October 2014 were retrospectively reviewed. Patients with previous mechanical or transcatheter valves, active endocarditis and concomitant cardiac procedures were excluded. Patient characteristics, preoperative data, post-procedural complications, and 30-day mortality were collected from a designated database. Mean values SD were calculated for all continuous variables. Counts and percentages were calculated for categorical variables. The Chi-square and Fisher exact tests were used to compare categorical variables. Continuous variables were compared using the t-test for independent samples. A 2-sided P value <0.05 was considered statistically significant. Results A total of 102 patients fulfilled the inclusion criteria, 50 patients (49%) underwent a transcatheter valve-in-valve procedure, while 52 patients (51%) underwent redo-surgery. Patients in the TAV-in-SAV group were significantly older, had a higher mean logistic EuroSCORE and exhibited a lower mean left ventricular ejection fraction than patients in the SAV-in-SAV group (78.16.7 vs. 66.213.1, P<0.001; 27.418.7 vs. 14.410, P<0.001; and 49.813.1 vs. 56.715.8, P=0.019 respectively). Postoperative pacemaker implantation and chest tube output were higher in the SAV-in-SAV group compared to the TAV-in-SAV group [11 (21%) vs. 3 (6%), P=0.042 and 0.91.0 vs. 0.60.9, P=0.047, respectively]. There was no significant difference in myocardial infarction, stroke or dialysis postoperatively. Thirty-day mortality was not significantly different between the two groups [TAV-in-SAV2 (4%) vs. SAV-in-SAV0, P=0.238]. Kaplan-Meier (KM) 1-year survival was significantly lower in the TAV-in-SAV group than in the SAV-in-SAV group (83% vs. 96%, P<0.001). Conclusions The present investigation shows that both groups, irrespective of different baseline comorbidities, show very good early clinical outcomes. While redo surgery is still the standard of care, a subgroup of patients may profit from the transcatheter valve-in-valve procedure. PMID:26543594

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

    PubMed

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

    2016-01-01

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

  12. A longitudinal comparison of tooth whitening resulting from dentifrice use.

    PubMed

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

    1998-01-01

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

  13. Three Ways To Be a Saber-Toothed Cat

    NASA Astrophysics Data System (ADS)

    Martin, L. D.; Babiarz, J. P.; Naples, V. L.; Hearst, J.

    Saber-toothed carnivores, until now, have been divided into two groups: scimitar-toothed cats with shorter, coarsely serrated canines coupled with long legs for fast running, and dirk-toothed cats with more elongate, finely serrated canines coupled to short legs built for power rather than speed. In the Pleistocene of North America, as in Europe, the scimitar-cat was Homotherium; the North American dirk-tooth was Smilodon. We now describe a new sabercat from the Early Pleistocene of Florida, combining the scimitar-tooth canine with the short, massive limbs of a dirk-tooth predator. This presents a third way to construct a saber-toothed carnivore.

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

    NASA Astrophysics Data System (ADS)

    Torres, Mara; Ricote, Jess; Amorn, Harvey; Jaafar, Miriam; Holgado, Susana; Piqueras, Juan; Asenjo, Agustina; Garca-Hernndez, Mar; Alguer, Miguel

    2011-12-01

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

  15. Critical appraisal. In-office tooth whitening: pulpal effects and tooth sensitivity issues.

    PubMed

    Kwon, So Ran; Swift, Edward J

    2014-01-01

    In-office bleaching is an effective method for whitening teeth.Tooth sensitivity associated with in-office whitening is reversible and may range from mild to considerable. The incidence and severity of tooth sensitivity can be reduced by pretreatment with a desensitizer such as potassium nitrate. Histologic studies and clinical studies on long-term pulpal effects are lacking to definitively support the safety of in-office tooth whitening. Future studies on the etiology of tooth sensitivity related to whitening might greatly improve the means of preventing and managing this side effect. PMID:25493305

  16. Robust tooth surface reconstruction by iterative deformation.

    PubMed

    Jiang, Xiaotong; Dai, Ning; Cheng, Xiaosheng; Wang, Jun; Peng, Qingjin; Liu, Hao; Cheng, Cheng

    2016-01-01

    Digital design technologies have been applied extensively in dental medicine, especially in the field of dental restoration. The all-ceramic crown is an important restoration type of dental CAD systems. This paper presents a robust tooth surface reconstruction algorithm for all-ceramic crown design. The algorithm involves three necessary steps: standard tooth initial positioning and division; salient feature point extraction using Morse theory; and standard tooth deformation using iterative Laplacian Surface Editing and mesh stitching. This algorithm can retain the morphological features of the tooth surface well. It is robust and suitable for almost all types of teeth, including incisor, canine, premolar, and molar. Moreover, it allows dental technicians to use their own preferred library teeth for reconstruction. The algorithm has been successfully integrated in our Dental CAD system, more than 1000 clinical cases have been tested to demonstrate the robustness and effectiveness of the proposed algorithm. PMID:26638148

  17. Tooth brushing inhibits oral bacteria in dogs

    PubMed Central

    WATANABE, Kazuhiro; HAYASHI, Kotaro; KIJIMA, Saku; NONAKA, Chie; YAMAZOE, Kazuaki

    2015-01-01

    In this study, scaling, polishing and daily tooth brushing were performed in 20 beagle dogs, and the number of oral bacteria was determined using a bacterial counter. The dogs were randomized into the scaling (S), scaling + polishing (SP), scaling + tooth daily brushing (SB) and scaling + polishing + tooth daily brushing (SPB) groups. Samples were collected from the buccal surface of the maxillary fourth premolars of the dogs immediately after scaling and every week thereafter from weeks 1 to 8. Throughout the study, the number of bacteria was significantly lower in the SB and SPB groups compared with the S group. The findings suggest that daily tooth brushing inhibited oral bacterial growth in the dogs. PMID:25994486

  18. Breast Implants

    MedlinePLUS

    ... sale in the United States: saline-filled and silicone gel-filled. Both types have a silicone outer shell. They vary in size, shell thickness, ... implant them. Provide information on saline-filled and silicone gel-filled breast implants, including data supporting a ...

  19. Computer simulation of gear tooth manufacturing processes

    NASA Technical Reports Server (NTRS)

    Mavriplis, Dimitri; Huston, Ronald L.

    1990-01-01

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

  20. Tooth microwear formation rate in Gasterosteus aculeatus.

    PubMed

    Baines, D C; Purnell, M A; Hart, P J B

    2014-05-01

    Tooth microwear feature densities were significantly increased in a population of laboratory-reared three-spined stickleback Gasterosteus aculeatus in four days, after they were transferred from a limnetic feeding regime to a benthic feeding regime. These results show that even in aquatic vertebrates with non-occluding teeth, changes in feeding can cause changes in tooth microwear in just a few days, as in mammals. PMID:24773545

  1. Tooth microwear formation rate in Gasterosteus aculeatus

    PubMed Central

    Baines, D C; Purnell, M A; Hart, P J B

    2014-01-01

    Tooth microwear feature densities were significantly increased in a population of laboratory-reared three-spined stickleback Gasterosteus aculeatus in four days, after they were transferred from a limnetic feeding regime to a benthic feeding regime. These results show that even in aquatic vertebrates with non-occluding teeth, changes in feeding can cause changes in tooth microwear in just a few days, as in mammals. PMID:24773545

  2. Cracked tooth syndrome: Overview of literature.

    PubMed

    Hasan, Shamimul; Singh, Kuldeep; Salati, Naseer

    2015-01-01

    Pain is defined as an "unpleasant sensory and emotional feeling which is associated with actual or potential injury of tissue or expressed in terms of such injury." Tooth pain usually refers to pain around the teeth or jaws mainly as a result of a dental condition. Mostly, toothaches are caused by a carious cavity, a broken tooth, an exposed tooth root or gum disease. The toothache may sometimes be the result of radiating pain from structures in the vicinity of tooth and jaws (cardiac pain, ear, nose, throat pain, and sinusitis). Therefore, evaluation by both dentists and physicians are sometimes necessary to diagnose medical illnesses causing "toothache." Cracked tooth syndrome is a major diagnostic challenge in clinical practice. Accurate diagnosis and appropriate treatment are complicated due to lack of awareness of this condition and its bizarre clinical features. Early diagnosis has been linked with successful restorative management and good prognosis. This article provides a detailed literature on the causes, classification, signs and symptoms, diagnosis, and treatment planning of cracked tooth syndrome. PMID:26539363

  3. Tooth loss and atherosclerosis: the Nagahama Study.

    PubMed

    Asai, K; Yamori, M; Yamazaki, T; Yamaguchi, A; Takahashi, K; Sekine, A; Kosugi, S; Matsuda, F; Nakayama, T; Bessho, K

    2015-03-01

    Several epidemiologic studies have suggested that oral disease is a risk factor for cardiovascular disease (CVD). However, whether a clinically significant association exists between the 2 disorders remains controversial. Here, we investigated the association between tooth loss, as an indicator of oral disease, and arterial stiffness, as a marker of atherosclerosis, in Japanese adults. Cross-sectional data were collected for 8,124 persons aged 30 to 75 y with no history of tooth loss for noninflammatory reasons, such as orthodontic treatment, malposition, and trauma. Participants received a comprehensive dental examination and extensive in-person measurements of CVD risk factors, and arterial stiffness was evaluated using the cardio-ankle vascular index (CAVI). We examined the association between CAVI and tooth loss using general linear models with adjustment for age, sex, body mass index, smoking status, hemoglobin A1c, and a history of insulin or hypoglycemic medication depending on the model. In addition, we performed an analysis that included interaction terms of the centered variables tooth loss, sex, and age. The results of the multiple regression analysis that included the interaction terms detected that the relationship between CAVI and tooth loss was dependent on sex, with only men showing a positive correlation (β for interaction = 0.04; 95% confidence interval, 0.02-0.06). The findings from this study suggest that a linear relationship exists between tooth loss and degree of arterial stiffness and that the association differed depending on sex. PMID:25406168

  4. Cracked tooth syndrome: Overview of literature

    PubMed Central

    Hasan, Shamimul; Singh, Kuldeep; Salati, Naseer

    2015-01-01

    Pain is defined as an unpleasant sensory and emotional feeling which is associated with actual or potential injury of tissue or expressed in terms of such injury. Tooth pain usually refers to pain around the teeth or jaws mainly as a result of a dental condition. Mostly, toothaches are caused by a carious cavity, a broken tooth, an exposed tooth root or gum disease. The toothache may sometimes be the result of radiating pain from structures in the vicinity of tooth and jaws (cardiac pain, ear, nose, throat pain, and sinusitis). Therefore, evaluation by both dentists and physicians are sometimes necessary to diagnose medical illnesses causing toothache. Cracked tooth syndrome is a major diagnostic challenge in clinical practice. Accurate diagnosis and appropriate treatment are complicated due to lack of awareness of this condition and its bizarre clinical features. Early diagnosis has been linked with successful restorative management and good prognosis. This article provides a detailed literature on the causes, classification, signs and symptoms, diagnosis, and treatment planning of cracked tooth syndrome. PMID:26539363

  5. Osteoclastogenesis and Osteogenesis during Tooth Movement.

    PubMed

    Baloul, S Susan

    2016-01-01

    It is a well-known concept that bone remodeling occurs during orthodontic tooth movement. The orthodontic literature is vastly full of information about the changes occurring on the periodontal ligament level. However, changes occurring in the alveolar bone are being elucidated. The purpose of this chapter is to present some of the studies describing the bone changes associated with orthodontic tooth movement. Initiation of osteoclastogenesis requires inflammation in the adjacent area. Tissue biomarker RANKL responds to the compressive forces. Conversely, an increase in osteoprotegrin biomarker causes a decrease in RANKL and inhibits tooth movement. Osteocyte activity during tooth movement is not well understood. Emerging studies are showing the effect of osteocytes on orthodontic tooth movement. Nitric oxide (NO), produced by osteocytes, is an important regulator of bone response to loading and has been shown to mediate osteoclast activity. iNOS (which produces NO) has been shown to mediate inflammation-induced bone resorption on the compression side. Several molecules have been linked to osteogenesis in tooth movement: TGF-β, BSP, BMPs and epidermal growth factor. Osteogenesis on the tension side is not well understood. Studies have shown increase in the expression of Runx2 on the tension side. Additionally, eNOS (produces NO) mediates bone formation on the tension side. The concept of osteoclastogenesis and osteogenesis is being unraveled. PMID:26599120

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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.

  7. The effect of implant number and position on the stress behavior of mandibular implant retained overdentures: A three-dimensional finite element analysis.

    PubMed

    Topkaya, Tolga; Solmaz, Murat Yavuz

    2015-07-16

    The present study evaluated the effects of ball anchor abutment attached to implants with a 4.30 mm diameter and 11 mm insert length on stress distribution in a patient without any remaining teeth in the lower jaw. In the study, the stress analysis was performed for five different configurations (2 with 4 implant-supported and 3 with 2 implant-supported) and three different loading types using ANSYS Workbench software. The stresses measured in the 4 implant-supported models were lower compared to the stresses measured in the 2 implant-supported models. The stresses on the implants intensified on the cervical region of the implants. When the effects of the loading sites on the stress were examined, the loading on the first molar tooth produced the highest stresses on the implants. PMID:25862522

  8. Mini-Implants: New Possibilities in Interdisciplinary Treatment Approaches

    PubMed Central

    Sebastian, Biju

    2014-01-01

    The introduction of mini-implants has broadened the range of tooth movements possible by fixed appliance therapy alone. The limits of fixed orthodontic treatment have become more a matter of facial appearance than anchorage. Many complex cases which would previously have required surgery or functional appliances can now be treated with fixed appliance therapy using mini-implants. A mutilated dentition case where mini-implants were used to provide anchorage for intrusion of molars and retraction of anterior teeth is reported here to illustrate this point. PMID:25580307

  9. Management of end-stage erectile dysfunction and stress urinary incontinence after radical prostatectomy by simultaneous dual implantation using a single trans-scrotal incision: surgical technique and outcomes

    PubMed Central

    Martnez-Salamanca, Juan I; Espins, Estefana Linares; Moncada, Ignacio; Portillo, Luis Del; Carballido, Joaqun

    2015-01-01

    Stress urinary incontinence (SUI) and end-stage erectile dysfunction (ED) after radical prostatectomy (RP) can decrease a patient's quality of life (QoL). We describe a surgical technique involving scrotal incision for simultaneous dual implantation of an artificial urinary sphincter (AUS) and an inflatable penile prosthesis (IPP). Patients with moderate to severe SUI (>3 pads per day) and end-stage ED following RP were selected for dual implantation. An upper transverse scrotal incision was made, followed by bulbar urethra dissection and AUS cuff placement. Through the same incision, the corpora cavernosa was exposed, and an IPP positioned. Followed by extraperitoneal reservoirs placement and pumps introduced in the scrotum. Short-term, intra- and post-operative complications; continence status and erectile function; and patient satisfaction and QoL were recorded. A total of 32 patients underwent dual implantation. Early AUS-related complications were: AUS reservoir migration and urethral erosion. One case of distal corporal extrusion occurred. No prosthetic infection was reported. Over 96% of patients were socially the continent (?1 pad per day) and > 95% had sufficient erections for intercourse. Limitations of the study were the small number of patients, the lack of the control group using a perineal approach for AUS placement and only a 12 months follow-up. IPP and AUS dual implantation using a single scrotal incision technique is a safe and effective option in patients with SUI and ED after RP. Further studies on larger numbers of patients are warranted. PMID:25657083

  10. PERI-IMPLANT VERSUS PERIODONTAL WOUND HEALING

    PubMed Central

    Emecen-Huja, Pinar; Eubank, Tim D.; Shapiro, Vladimir; Yildiz, Vedat; Tatakis, Dimitris N.; Leblebicioglu, Binnaz

    2013-01-01

    Aim Peri-implant gingival healing following one-stage implant placement was investigated and compared to periodontal healing. Methods Healing at surgical sites (implant (I) and adjacent teeth (T+)) was compared to non-operated tooth (T-) in non-smokers receiving one-stage implant. Periodontal Indices (PI, GI) were recorded at surgery and up to 12 weeks postoperatively. Peri-implant (PICF) and gingival crevicular (GCF) fluids were analyzed for cytokines, collagenases and inhibitors. Data was analyzed by linear mixed model regression analysis and repeated measures ANOVA. Results 40 patients (22 female; 21-74 yrs old) completed the study. Surgical site GI, increased at week 1, decreased significantly during early healing (weeks 1-3; p=0.0003) and continually decreased during late healing (weeks 6-12) for I (p<0.01). PICF volume decreased 3-fold by week 12 (p=0.0003). IL-6, IL-8, MIP-1?, and TIMP-1 levels significantly increased at surgical sites at week one, significantly decreasing thereafter (P<0.016). Week one IL-6, IL-8 and MIP-1? levels were ~3-fold higher, and TIMP-1 levels 63% higher, at I compared to T+ (p=0.001). Conclusion Peri-implant gingival healing, as determined by crevicular fluid molecular composition, differs from periodontal healing. The observed differences suggest that peri-implant tissues, compared to periodontal tissues, represent a higher pro-inflammatory state. PMID:23772674

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

    PubMed

    Mandelaris, George A; Vlk, Scott D

    2014-01-01

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

  12. Presentation of two cases of immediate restoration of implants in the esthetic region, using facilitate software and guides with stereolithographic model surgery prior to patient surgery.

    PubMed

    Kamposiora, Phophi; Papavasiliou, George; Madianos, Phoebous

    2012-02-01

    Improvements in both implant microsurfaces and placement techniques have reduced healing time and increased survival rates. CAD/CAM technology and improved ceramic materials allow for achievement of improved esthetics at the implant restoration level. Two clinical procedures have the capacity to decrease patient postoperative discomfort and improve esthetics. Flapless surgery reduces surgical trauma and postoperative problems. Placement of the final prosthetic abutment at the time of implant placement stabilizes soft tissue adhesion and position to the implant. Both results require careful presurgical planning with precise implant and abutment placement. This is a clinical report of two cases that are part of a larger ongoing clinical trial of 20 patients. The inclusion criterion was that patients should be missing a single tooth in the esthetic zone. Facilitate software was used in conjunction with dicom files transferred from CT scans for diagnosis. Stereolithographic models and surgical guides were fabricated from the digital information. Surgical guides were used preoperatively so implant replicas could be placed in stereolithographic models as simulated surgery. A ZirDesign ceramic abutment was adapted on the model, and a provisional crown was fabricated. At the time of actual implant surgery, the same surgical guide was used with a flapless approach. The previously modified ceramic abutment was screw-retained and torqued to place into the implant. The provisional crown was then cemented after blocking out the screw access hole. A final restoration was fabricated from all-ceramic material after several months. Success requires careful patient selection and attention to each step of the technique. Preliminary outcomes from the ongoing clinical trial are promising. PMID:22050241

  13. Cochlear implants.

    PubMed

    Macherey, Olivier; Carlyon, Robert P

    2014-09-22

    Cochlear implants are the first example of a neural prosthesis that can substitute a sensory organ: they bypass the malfunctioning auditory periphery of profoundly-deaf people to electrically stimulate their auditory nerve. The history of cochlear implants dates back to 1957, when Djourno and Eyris managed, for the first time, to elicit sound sensations in a deaf listener using an electrode implanted in his inner ear. Since then, considerable technological and scientific advances have been made. Worldwide, more than 300,000 deaf people have been fitted with a cochlear implant; it has become a standard clinical procedure for born-deaf children and its success has led over the years to relaxed patient selection criteria; for example, it is now not uncommon to see people with significant residual hearing undergoing implantation. Although the ability to make sense of sounds varies widely among the implanted population, many cochlear implant listeners can use the telephone and follow auditory-only conversations in quiet environments. PMID:25247367

  14. Clinical Management of a Peri-Implant Giant Cell Granuloma

    PubMed Central

    Pacifici, A.; Carbone, D.; Marini, R.; Sfasciotti, G. L.; Pacifici, L.

    2015-01-01

    Purpose. Implant therapy plays an important role in contemporary dentistry with high rates of long-term success. However, in recent years, the incidence of peri-implantitis and implant failures has significantly increased. The peripheral giant cell granuloma (PGCG) rarely occurs in peri-implant tissues and it is clinically comparable to the lesions associated with natural teeth. Therefore, the study of possible diseases associated with dental implants plays an important role in order to be able to diagnose and treat these conditions. Materials and Methods. This report described a 60-year-old Caucasian male who presented a reddish-purple pedunculated mass, of about 2 cm in diameter, associated with a dental implant and the adjacent natural tooth. Results. An excisional biopsy was performed and the dental implant was not removed. Histological examination provided the diagnosis of PGCG. After 19-month follow-up, there were no signs of recurrence of peri-implantitis around the implant. Conclusion. The correct diagnosis and appropriate surgical treatment of peri-implant giant cell granuloma are very important for a proper management of the lesion in order to preserve the implant prosthetic rehabilitation and prevent recurrences. PMID:26788379

  15. Clinical Management of a Peri-Implant Giant Cell Granuloma.

    PubMed

    Pacifici, A; Carbone, D; Marini, R; Sfasciotti, G L; Pacifici, L

    2015-01-01

    Purpose. Implant therapy plays an important role in contemporary dentistry with high rates of long-term success. However, in recent years, the incidence of peri-implantitis and implant failures has significantly increased. The peripheral giant cell granuloma (PGCG) rarely occurs in peri-implant tissues and it is clinically comparable to the lesions associated with natural teeth. Therefore, the study of possible diseases associated with dental implants plays an important role in order to be able to diagnose and treat these conditions. Materials and Methods. This report described a 60-year-old Caucasian male who presented a reddish-purple pedunculated mass, of about 2?cm in diameter, associated with a dental implant and the adjacent natural tooth. Results. An excisional biopsy was performed and the dental implant was not removed. Histological examination provided the diagnosis of PGCG. After 19-month follow-up, there were no signs of recurrence of peri-implantitis around the implant. Conclusion. The correct diagnosis and appropriate surgical treatment of peri-implant giant cell granuloma are very important for a proper management of the lesion in order to preserve the implant prosthetic rehabilitation and prevent recurrences. PMID:26788379

  16. Comprehensive treatment approach for bilateral cleft lip and palate in an adult with premaxillary osteotomy, tooth autotransplantation, and 2-jaw surgery.

    PubMed

    Kokai, Satoshi; Fukuyama, Eiji; Sato, Yutaka; Hsu, Jui-Chin; Takahashi, Yuzo; Harada, Kiyoshi; Ono, Takashi

    2015-01-01

    We report the successful treatment of a woman aged 25 years 3 months with bilateral cleft lip and palate. She had a protruded premaxilla, collapsed posterior segments, wide alveolar defects with oronasal fistulae, a congenital missing tooth, and severe facial asymmetry with a transverse occlusal cant. The comprehensive treatment approach included (1) premaxillary osteotomy combined with alveolar bone grafting to reposition the premaxilla and minimize the wide alveolar defects, (2) autotransplantation of a tooth with complete root formation to the grafted bone region to restore the missing tooth without a prosthesis such as a dental implant or bridge, and (3) 2-jaw surgery to improve facial asymmetry. The premaxillary osteotomy was managed orthodontically, in combination with bone grafting. The results suggest that surgical orthodontic treatment with tooth autotransplantation might be useful to improve the occlusion and facial esthetics without prosthetics. PMID:25533078

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

    PubMed Central

    Bilhan, Hakan; Mumcu, Emre

    2011-01-01

    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. PMID:22087416

  18. Adhesion of Dental Materials to Tooth Structure

    NASA Astrophysics Data System (ADS)

    Mitra, Sumita B.

    2000-03-01

    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.

  19. Fracture analysis of randomized implant-supported fixed dental prostheses

    PubMed Central

    Esquivel-Upshaw, Josephine F.; Mehler, Alex; Clark, Arthur E.; Neal, Dan; Anusavice, Kenneth J.

    2014-01-01

    Objective Fractures of posterior fixed dental all-ceramic prostheses can be caused by one or more factors including prosthesis design, flaw distribution, direction and magnitude of occlusal loading, and nature of supporting infrastructure (tooth root/implant), and presence of adjacent teeth. This clinical study of implant-supported, all-ceramic fixed dental prostheses, determined the effects of (1) presence of a tooth distal to the most distal retainer; (2) prosthesis loading either along the non-load bearing or load bearing areas; (3) presence of excursive contacts or maximum intercuspation contacts in the prosthesis; and (4) magnitude of bite force on the occurrence of veneer ceramic fracture. Methods 89 implant-supported FDPs were randomized as either a three-unit posterior metal-ceramic (Au-Pd-Ag alloy and InLine POM, Ivoclar, Vivadent) FDP or a ceramic-ceramic (ZirCAD and ZirPress, Ivoclar, Vivadent) FDP. Two implants (Osseospeed, Dentsply) and custom abutments (Atlantis, Dentsply) supported these FDPs, which were cemented with resin cement (RelyX Universal Cement). Baseline photographs were made with markings of teeth from maximum intercuspation (MI) and excursive function. Patients were recalled at 6 months and 1 to 3 years. Fractures were observed, their locations recorded, and images compared with baseline photographs of occlusal contacts. Conclusion No significant relationship exists between the occurrence of fracture and: (1) the magnitude of bite force; (2) a tooth distal to the most distal retainer; and (3) contacts in load-bearing or non-load-bearing areas. However, there was a significantly higher likelihood of fracture in areas with MI contacts only. Clinical Significance This clinical study demonstrates that there is a need to evaluate occlusion differently with implant-supported prostheses than with natural tooth supported prostheses because of the absence of a periodontal ligament. Implant supported prostheses should have minimal occlusion and lighter contacts than ones supported by natural dentition. PMID:25016139

  20. Cochlear implant

    MedlinePLUS

    ... of the implant to be inserted. The electrode array is passed into the inner ear (cochlea). The ... antibiotics to prevent infection. Many surgeons place a large dressing over the operated ear. The dressing is ...

  1. 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 ...

  2. Immediate Implant Placement in Anterior Aesthetic Region and Assessment using Cone-Beam Computed Tomography Scan Technology

    PubMed Central

    Joshi, Vaibhav; Gupta, Shalini

    2015-01-01

    The esthetics and functional integrity of the periodontal tissues may be compromised by the dental loss. Dental implants have become an additional tool in the armamentarium of treatment options to offer the patient for the replacement of a missing tooth or teeth. Diagnosis and treatment planning is the key factors in achieving the successful outcome after placing and restoring implants placed immediately after tooth extraction. The introduction of cone-beam computed tomography (CBCT) for the maxillofacial region provides opportunities for dental practitioners to request multiplanar imaging. This case report demonstrates the use of CBCT scan technology in immediate implant placement in the maxillary anterior teeth region. PMID:26668494

  3. Tooth model reconstruction based upon data fusion for orthodontic treatment simulation.

    PubMed

    Yau, Hong-Tzong; Yang, Tsan-Jui; Chen, Yi-Chen

    2014-05-01

    This paper proposes a full tooth reconstruction method by integrating 3D scanner data and computed tomography (CT) image sets. In traditional dental treatment, plaster models are used to record patient?s oral information and assist dentists for diagnoses. However, plaster models only save surface information, and are therefore unable to provide further information for clinical treatment. With the rapid development of medical imaging technology, computed tomography images have become very popular in dental treatment. Computed tomography images with complete internal information can assist the clinical diagnosis for dental implants or orthodontic treatment, and a digital dental model can be used to simulate and predict results before treatment. However, a method of producing a high quality and precise dental model has yet to be developed. To this end, this paper presents a tooth reconstruction method based on the data fusion concept via integrating external scanned data and CT-based medical images. First, a plaster model is digitized with a 3D scanner. Then, each crown can be separated from the base according to the characteristics of tooth. CT images must be processed for feature enhancement and noise reduction, and to define the tooth axis direction which will be used for root slicing. The outline of each slice of dental root can then be determined by the level set algorithm, and converted to point cloud data. Finally, the crown and root data can be registered by the iterative closest point (ICP) algorithm. With this information, a complete digital dental model can be reconstructed by the Delaunay-based region-growing (DBRG) algorithm. The main contribution of this paper is to reconstruct a high quality customized dental model with root information that can offer significant help to the planning of dental implant and orthodontic treatment. PMID:24631784

  4. Malformations of the tooth root in humans.

    PubMed

    Luder, Hans U

    2015-01-01

    The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation. PMID:26578979

  5. Malformations of the tooth root in humans

    PubMed Central

    Luder, Hans U.

    2015-01-01

    The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation. PMID:26578979

  6. An evolutionary view on tooth development and replacement in wild Atlantic salmon (Salmo salar L.).

    PubMed

    Huysseune, A; Witten, P E

    2008-01-01

    To gain an insight into the evolution of tooth replacement mechanisms, we studied the development of first-generation and replacement teeth on the dentary of wild Atlantic salmon (Salmo salar L.), a protacanthopterygian teleost, using serially sectioned heads of early posthatching stages as well as adults. First-generation teeth develop within the oral epithelium. The anlage of the replacement tooth is first seen as a placode-like thickening of the outer dental epithelium of the predecessor, at its lingual and caudal side. Ongoing development of the replacement tooth germ is characterized by the elaboration of a population of epithelial cells, termed here the middle dental epithelium, apposed to the inner dental epithelium on the lingual side of the tooth germ. Before the formation of the new successor, a single-layered outer dental epithelium segregates from the middle dental epithelium. The dental organs of the predecessor and the successor remain broadly interconnected. The absence of a discrete successional dental lamina in salmon stands in sharp contrast to what is observed in other teleosts, even those that share with salmon the extraosseous formation of replacement teeth. The mode of tooth replacement in Atlantic salmon displays several characters similar to those observed in the shark Squalus acanthias. To interpret similarities in tooth replacement between Atlantic salmon and chondrichthyans as a case of convergence, or to see them as a result of a heterochronic shift, requires knowledge on the replacement process in more basal actinopterygian lineages. The possibility that the middle dental epithelium functionally substitutes for a successional lamina, and could be a source of stem cells, whose descendants subsequently contribute to the placode of the new replacement tooth, needs to be explored. PMID:18184353

  7. Effect of cardiac resynchronization therapy with implantable cardioverter defibrillator versus cardiac resynchronization therapy with pacemaker on mortality in heart failure patients: results of a high-volume, single-centre experience

    PubMed Central

    Kutyifa, Valentina; Geller, Laszlo; Bogyi, Peter; Zima, Endre; Aktas, Mehmet K; Ozcan, Emin Evren; Becker, David; Nagy, Vivien Klaudia; Kosztin, Annamaria; Szilagyi, Szabolcs; Merkely, Bela

    2014-01-01

    Aims There are limited and contradictory data on the effects of CRT with implantable cardioverter defibrillator (CRT-D) on mortality as compared with CRT with pacemaker (CRT-P). Methods and results We evaluated the long-term outcome of patients implanted with a CRT-D or CRT-P device in our high-volume single-centre experience. Data on all-cause mortality were derived from clinic visits and the Hungarian National Healthcare Fund Death Registry. KaplanMeier survival analyses and multivariate Cox regression models were used to evaluate all-cause mortality in patients with CRT-D vs. CRT-P, stratified by the aetiology of cardiomyopathy. From 2000 to 2011, 1122 CRT devices, 693 CRT-P (LVEF 28.2??7.4%) and 429 CRT-D (LVEF 27.6??6.4%), were implanted at our centre. During the median follow-up of 28 months, 379 patients died from any cause, 250 patients (36%) with an implanted CRT-P and 129 patients (30%) with an implanted CRT-D. There was no evidence of mortality benefit in patients implanted with a CRT-D compared with a CRT-P in the total cohort [hazard ratio (HR) 0.98, 95% confidence interval (CI) 0.731.32, P?=?0.884]. In patients with ischaemic cardiomyopathy, CRT-D treatment was associated with a significant 30% risk reduction in all-cause mortality compared with an implanted CRT-P (HR 0.70, 95% CI 0.510.97, P?=?0.03). In non-ischaemic patients, there was no mortality benefit of CRT-D over CRT-P (HR 0.98, 95% CI 0.731.32, P?=?0.894, interaction P-value?=?0.15). Conclusions In heart failure patients with ischaemic cardiomyopathy, CRT-D was associated with a mortality benefit compared with CRT-P, but no benefit of CRT-D over CRT-P in mortality was observed in non-ischaemic cardiomyopathy. PMID:25379962

  8. Detecting Tooth Damage in Geared Drive Trains

    NASA Technical Reports Server (NTRS)

    Nachtsheim, Philip R.

    1997-01-01

    This paper describes a method that was developed to detect gear tooth damage that does not require a priori knowledge of the frequency characteristic of the fault. The basic idea of the method is that a few damaged teeth will cause transient load fluctuations unlike the normal tooth load fluctuations. The method attempts to measure the energy in the lower side bands of the modulated signal caused by the transient load fluctuations. The method monitors the energy in the frequency interval which excludes the frequency of the lowest dominant normal tooth load fluctuation and all frequencies above it. The method reacted significantly to the tooth fracture damage results documented in the Lewis data sets which were obtained from tests of the OH-58A transmission and tests of high contact ratio spiral bevel gears. The method detected gear tooth fractures in all four of the high contact ratio spiral bevel gear runs. Published results indicate other detection methods were only able to detect faults for three out of four runs.

  9. [Cochlear implants].

    PubMed

    Gersdorff, M

    1997-01-01

    Cochlear implants aim at the rehabilitation of profound bilateral deafness. The cochlear implant is a prosthesis made out of surgically implanted cochlear electrodes connected to an external vocal processor. The external acoustic signals are converted into electrical signals coded by the vocal processor. They are then sent out, by a transcutaneous mode, to an internal receptor. This receptor transmits the information to the intracochlear electrodes. Initially, the cochlear implantation was recommended to patients totally deaf following a trauma, a degenerative disease of the inner ear, a meningitis or the use of ototoxic drugs. These patients could not gain from conventional hearing aids and were condemned to silence. More recently, the authors have been impressed by spectacular results with patients having lost their hearing during adulthood (postlingual). The challenge here is quite different, as its aim is to open up--and not to reopen--a child to a sensation that he has never perceived before. This allows the child to develop a coding, a recognition of the acoustic message. The first results are very encouraging. Scientifically, the implantation is also a research tool in various fields: surgical, neurophysiological, neuropsychological, speech therapy, social and cultural. The cochlear implant is an "avant-garde" project. It has changed our approach to profound deafness. It represents the only hope for the profoundly deaf person to reach a satisfactory rehabilitation and social integration. PMID:9532864

  10. Danger: implants.

    PubMed

    Findlay, S; Podolsky, D

    1992-08-24

    The superheated debate over breast implants awakened a sleeping giant of an issue clouding "medical devices"--the government's clumsy nomenclature for any medical product that is not a drug, from breast implants and artificial hips to X-ray machines and surgical thread. Some 130 categories of high-risk devices are in use with little or no proof of safety, reliability or effectiveness. All appeared before 1976, the year that the Food and Drug Administration got the authority to regulate such products. Under activist chief David Kessler and with added clout from a 1990 law, the FDA plans to scrutinize the entire 130-item list. Five will get special attention starting early next year: saline-filled breast implants, inflatable penile implants, testicular implants, heart-bypass pumps and cranial stimulators. U.S. News has looked at all five devices, using FDA data obtained through the Freedom of Information Act. In-depth computer analysis suggested that penile implants deserve closer examination. Why is clear from the following report. PMID:10171242

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

    PubMed

    Christen, Arden G; Christen, Joan A

    2011-01-01

    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

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

    PubMed

    Kamburo?lu, K?van; Gl?ah?, Ay?e; Gen, Yasemin; Paksoy, Candan Semra

    2012-06-01

    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

  13. Autogenous Tooth Transplantation as a Treatment Option

    PubMed Central

    Aggarwal, Rashmi; Chugh, Vinay Kumar; Wadhwa, Puneet; Kohli, Munish

    2012-01-01

    ABSTRACT Autogenous tooth transplantation is the surgical movement of a tooth from one location in the mouth to another in the same individual. Though done for years but it has achieved variable success rates. Although the indications for autotransplantation are narrow, careful patient selection coupled with an appropriate technique can lead to exceptional esthetic and functional results. This article discusses the reviews of previous works done and highlights the criteria and factors influencing the success of autotransplant along with reports of two cases of transplantation of impacted and malposed canine. How to cite this article: Chugh A, Aggarwal R, Chugh VK, Wadhwa P, Kohli M. Autogenous Tooth Transplantation as a Treatment Option. Int J Clin Pediatr Dent 2012;5(1):87-92. PMID:25206143

  14. Cytokine Expression and Accelerated Tooth Movement

    PubMed Central

    Teixeira, C.C.; Khoo, E.; Tran, J.; Chartres, I.; Liu, Y.; Thant, L.M.; Khabensky, I.; Gart, L.P.; Cisneros, G.; Alikhani, M.

    2010-01-01

    It has been shown that inhibiting the expression of certain cytokines decreases the rate of tooth movement. Here, we hypothesized that stimulating the expression of inflammatory cytokines, through small perforations of cortical bone, increases the rate of bone remodeling and tooth movement. Forty-eight rats were divided into 4 groups: 50-cN force applied to the maxillary first molar (O), force application plus soft tissue flap (OF), force application plus flap plus 3 small perforations of the cortical plate (OFP), and a control group (C). From the 92 cytokines studied, the expression of 37 cytokines increased significantly in all experimental groups, with 21 cytokines showing the highest levels in the OFP group. After 28 days, micro-computed tomography, light and fluorescent microscopy, and immunohistochemistry demonstrated higher numbers of osteoclasts and bone remodeling activity in the OFP group, accompanied by generalized osteoporosity and increased rate of tooth movement. PMID:20639508

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

    PubMed Central

    Winkler, Daniela E.; Kaiser, Thomas M.

    2015-01-01

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

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

    PubMed

    Winkler, Daniela E; Kaiser, Thomas M

    2015-01-01

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

  17. Interactive tooth partition of dental mesh base on tooth-target harmonic field.

    PubMed

    Zou, Bei-ji; Liu, Shi-jian; Liao, Sheng-hui; Ding, Xi; Liang, Ye

    2015-01-01

    The accurate tooth partition of dental mesh is a crucial step in computer-aided orthodontics. However, tooth boundary identification is not a trivial task for tooth partition, since different shapes and their arrangements vary substantially among common clinical cases. Though curvature field is traditionally used for identifying boundaries, it is normally not reliable enough. Other methods may improve the accuracy, but require intensive user interaction. Motivated by state-of-the-art general interactive mesh segmentation methods, this paper proposes a novel tooth-target partition framework that employs harmonic fields to partition teeth accurately and effectively. In addition, a refining strategy is introduced to successfully segment teeth from the complicated dental model with indistinctive tooth boundaries on its lingual side surface, addressing an issue that had not been solved properly before. To utilise high-level information provided by the user, smart and intuitive user interfaces are also proposed with minimum interaction. In fact, most published interactive methods specifically designed for tooth partition are lacking efficient user interfaces. Extensive experiments and quantitative analyses show that our tooth partition method outperforms the state-of-the-art approaches in terms of accuracy, robustness and efficiency. PMID:25464355

  18. A visco-elastic model for the prediction of orthodontic tooth movement.

    PubMed

    Van Schepdael, An; De Bondt, Kris; Geris, Liesbet; Sloten, Jos Vander

    2014-01-01

    This study presents a biomechanical model of orthodontic tooth movement. Although such models have already been presented in the literature, most of them incorporate computationally expensive finite elements (FE) methods to determine the strain distribution in the periodontal ligament (PDL). In contrast, the biomechanical model presented in this work avoids the use of FE methods. The elastic deformation of the PDL is modelled using an analytical approach, which does not require setting up a 3D model of the tooth. The duration of the lag phase is estimated using the calculated hydrostatic stresses, and bone remodelling is predicted by modelling the alveolar bone as a viscous material. To evaluate the model, some typically used motion patterns were simulated and a sensitivity analysis was carried out on the parameters. Results show that despite some shortcomings, the model is able to describe commonly used motion patterns in orthodontic tooth movement, in both single- and multi-rooted teeth. PMID:22788245

  19. Age of an Indonesian Fossil Tooth Determined by Electron Paramagnetic Resonance

    SciTech Connect

    Bogard, JS

    2004-04-07

    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.

  20. The Pathology of Bone Tissue during Peri-Implantitis

    PubMed Central

    Schminke, B.; vom Orde, F.; Gruber, R.; Schliephake, H.; Bürgers, R.

    2015-01-01

    Dental implants are one of the most frequently used treatment options for tooth replacement. Approximately 30% of patients with dental implants develop peri-implantitis, which is an oral inflammatory disease that leads to loss of the supporting tissues, predominately the bone. For the development of future therapeutic strategies, it is essential to understand the molecular pathophysiology of human dental peri-implant infections. Here, we describe the gene and protein expression patterns of peri-implantitis bone tissue compared with healthy peri-implant bone tissue. Furthermore, cells from the osteoblastic lineage derived from peri-implantitis samples were immortalized and characterized. We applied microarray, quantitative reverse transcription polymerase chain reaction, fluorescence-activated cell sorting, and Western blot analyses. The levels of typical bone matrix molecules, including SPP1, BGLAP, and COL9A1, in patients with peri-implantitis were reduced, while the inflammation marker interleukin 8 (IL8) was highly expressed. RUNX2, one of the transcription factors of mature osteoblasts, was also decreased in peri-implantitis. Finally, the human telomerase reverse transcriptase immortalized cell line from peri-implantitis exhibited a more fibro-osteoblastic character than did the healthy control. PMID:25406169

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

    SciTech Connect

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

    2013-07-15

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

  2. Charcot-Marie-Tooth disease and vincristine.

    PubMed

    Orejana-Garca, Angel M; Pascual-Huerta, Javier; Prez-Melero, Andrs

    2003-01-01

    This article reports on a case of sensorimotor neuropathy in a 55-year-old man that developed after vincristine therapy. Subsequent biopsy of the sural nerve and electromyographic studies revealed the presence of Charcot-Marie-Tooth disease. Only 17 patients who developed severe neuropathy with very low accumulated doses of vincristine have been described in the literature. Pain and lateral ankle instability were treated with a functional orthosis. Orthopedic treatment and the biomechanical basis of foot and ankle problems in patients with vincristine therapy-induced Charcot-Marie-Tooth disease are discussed. PMID:12756314

  3. Assessment of dehydrothermally cross‐linked collagen membrane for guided bone regeneration around peri-implant dehiscence defects: a randomized single-blinded clinical trial

    PubMed Central

    2015-01-01

    Purpose The aim of this study was to determine the clinical feasibility of using dehydrothermally cross‐linked collagen membrane (DCM) for bone regeneration around peri-implant dehiscence defects, and compare it with non-cross-linked native collagen membrane (NCM). Methods Dehiscence defects were investigated in twenty-eight patients. Defect width and height were measured by periodontal probe immediately following implant placement (baseline) and 16 weeks afterward. Membrane manipulation and maintenance were clinically assessed by means of the visual analogue scale score at baseline. Changes in horizontal thickness at 1 mm, 2 mm, and 3 mm below the top of the implant platform and the average bone density were assessed by cone-beam computed tomography at 16 weeks. Degradation of membrane was histologically observed in the soft tissue around the implant prior to re-entry surgery. Results Five defect sites (two sites in the NCM group and three sites in the DCM group) showed soft-tissue dehiscence defects and membrane exposure during the early healing period, but there were no symptoms or signs of severe complications during the experimental postoperative period. Significant clinical and radiological improvements were found in all parameters with both types of collagen membrane. Partially resorbed membrane leaflets were only observed histologically in the DCM group. Conclusions These findings suggest that, compared with NCM, DCM has a similar clinical expediency and possesses more stable maintenance properties. Therefore, it could be used effectively in guided bone regeneration around dehiscence-type defects. PMID:26732806

  4. Genetics Home Reference: Charcot-Marie-Tooth disease

    MedlinePLUS

    ... early adulthood, but onset may occur anytime from early childhood through late adulthood. Symptoms of Charcot-Marie-Tooth ... a term sometimes used to describe a severe, early childhood form of Charcot-Marie-Tooth disease; it is ...

  5. Unintentional root fragment retention in proximity to dental implants: a series of six human case reports.

    PubMed

    Langer, Laureen; Langer, Burton; Salem, Daliah

    2015-01-01

    There has been renewed interest in intentionally placing dental implants in proximity to or in contact with tooth root fragments. In clinical practice, human teeth are usually extracted due to nonrestorable caries, vertical or horizontal root fractures, periodontal disease, or endodontic failure, which is commonly accompanied by inflammation and bacterial contamination. The aim of this case series is to present the adverse effects in humans of clinically undetected root-to-implant contact (CURIC), where implants were unintentionally placed in proximity to undetected retained root fragments. The adverse effects of small (3 to 5 mm) root fragments were detectible 6 to 48 months post implant placement. Three out of seven implants in six patients were removed due to severe coronal bone loss. This differs from retrograde peri-implantitis, where only the apical area of the implant is affected and the coronal portion remains integrated. The detrimental effect of root fragment-to-implant contact is described along with its clinical management. Based on the review of currently relevant data, mixed results have been documented regarding the success of dental implants in proximity to tooth-root fragments. Careful evaluation of long-term, postloading results in humans where hopeless teeth have been extracted due to infection and significant bone loss are required before intentional root fragment retention is considered a safe and reliable clinical option for implant placement. PMID:25909518

  6. Mechanisms Underlying Ectopic Persistent Tooth-Pulp Pain following Pulpal Inflammation

    PubMed Central

    Matsuura, Shingo; Shimizu, Kohei; Shinoda, Masamichi; Ohara, Kinuyo; Ogiso, Bunnai; Honda, Kuniya; Katagiri, Ayano; Sessle, Barry J.; Urata, Kentaro; Iwata, Koichi

    2013-01-01

    In order to clarify the peripheral mechanisms of ectopic persistent pain in a tooth pulp following pulpal inflammation of an adjacent tooth, masseter muscle activity, phosphorylated extracellular signal-regulated protein kinase (pERK) and TRPV1 immunohistochemistries and satellite cell activation using glial fibrillary acidic protein (GFAP) immunohistochemistry in the trigeminal ganglion (TG) were studied in the rats with molar tooth-pulp inflammation. And, Fluorogold (FG) and DiI were also used in a neuronal tracing study to analyze if some TG neurons innervate more than one tooth pulp. Complete Freund’s adjuvant (CFA) or saline was applied into the upper first molar tooth pulp (M1) in pentobarbital-anesthetized rats, and capsaicin was applied into the upper second molar tooth pulp (M2) on day 3 after the CFA or saline application. Mean EMG activity elicited in the masseter muscle by capsaicin application to M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. The mean number of pERK-immunoreactive (IR) TG cells was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. Application of the satellite cell inhibitor fluorocitrate (FC) into TG caused a significant depression of capsaicin-induced masseter muscle activity and a significant reduction of satellite cell activation. The number of TRPV1-IR TG cells innervating M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats, and that was decreased following FC injection into TG. Furthermore, 6% of TG neurons innervating M1 and/or M2 innervated both M1 and M2. These findings suggest that satellite cell activation following tooth pulp inflammation and innervation of multiple tooth pulps by single TG neurons may be involved in the enhancement of the activity of TG neurons innervating adjacent non-inflamed teeth that also show enhancement of TRPV1 expression in TG neurons, resulting in the ectopic persistent tooth-pulp pain following pulpal inflammation of adjacent teeth. PMID:23341909

  7. Palatal positioned implants in severely atrophic maxillae versus conventional implants to support fixed full-arch prostheses: Controlled retrospective study with 5 years of follow-up

    PubMed Central

    Candel-Marti, Eugenia; Peñarrocha-Oltra, David; Bagán, Leticia; Peñarrocha-Diago, Maria

    2015-01-01

    Background To evaluate soft tissue conditions and bone loss around palatal positioned implants supporting fixed full-arch prostheses to rehabilitate edentulous maxillae with horizontal atrophy and compare them with conventional well-centered implants placed in non-atrophic maxillae after a minimum follow-up of 5 years. Material and Methods A clinical retrospective study was performed of patients that were rehabilitated with full-arch fixed implant-supported maxillary prostheses and had a minimum follow-up of 5 years after implant loading. Patients were divided into 2 groups: patients with class IV maxilla according to Cawood and Howell and treated with palatal positioned implants (test) and with class III maxilla and treated with implants well-centered in the alveolar ridge and completely surrounded by bone (control). The following variables were assessed: age, sex, frequency of tooth brushing, smoking, type of prosthesis, type of implant, implant success, amount of buccal keratinized mucosa, buccal retraction, probing depth, plaque index, modified bleeding index, presence of mucositis or peri-implantitis and peri-implant bone loss. Statistical analysis was performed applying Chi2 Test and Student’s t-test using alpha set at 0.05. Results A total of 57 patients were included: 32 patients with 161 palatal positioned implants (test) and 25 patients with 132 well centered implants (control). No statistically significant differences were found regarding age, sex and smoking, but test group patients reported a significantly higher frequency of daily tooth brushing. Implant success rates were 96.9% for test group implants and 96.0% for control group implants. Peri-implant mucosa retraction was significantly higher in the control group than in the test group (p=0,017). No significant differences were observed either for all the other assessed clinical parameters or for peri-implant bone loss. Conclusions Despite its limitations the outcomes of the present study suggest that palatal positioned implants may be a good treatment alternative for patients with severe horizontal maxillary alveolar bone atrophy. Palatal positioned implants presented similar success rates, soft tissue conditions and peri-implant bone loss than well-centered implants placed completely surrounded by bone in non-atrophic ridges. Key words: Atrophic maxilla, bone atrophy, fixed dental prosthesis, dental implants. PMID:25662546

  8. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Preformed plastic denture tooth. 872.3590 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated device, composed of materials such as...

  9. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Preformed plastic denture tooth. 872.3590 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated device, composed of materials such as...

  10. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Preformed plastic denture tooth. 872.3590 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated device, composed of materials such as...

  11. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Preformed plastic denture tooth. 872.3590 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated device, composed of materials such as...

  12. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Preformed plastic denture tooth. 872.3590 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated device, composed of materials such as...

  13. The Importance of Tooth Decay Prevention in Children under Three

    ERIC Educational Resources Information Center

    Milgrom, Peter; Huebner, Colleen; Chi, Donald

    2010-01-01

    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

  14. Impact of gin saw tooth design on textile processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toothed gin saws have been used to separate cotton fiber from the seed for over 200 years. There have been many saw tooth designs developed over the years. Most of these designs were developed by trial and error. A complete and scientific analysis of tooth design has never been done. It is not k...

  15. The Importance of Tooth Decay Prevention in Children under Three

    ERIC Educational Resources Information Center

    Milgrom, Peter; Huebner, Colleen; Chi, Donald

    2010-01-01

    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…

  16. 21 CFR 872.3200 - Resin tooth bonding agent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Resin tooth bonding agent. 872.3200 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a) Identification. A resin tooth bonding agent is a device material, such as methylmethacrylate, intended to be...

  17. 21 CFR 872.3690 - Tooth shade resin material.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tooth shade resin material. 872.3690 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A...

  18. 21 CFR 872.3690 - Tooth shade resin material.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Tooth shade resin material. 872.3690 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A...

  19. 21 CFR 872.5525 - Preformed tooth positioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Preformed tooth positioner. 872.5525 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5525 Preformed tooth positioner. (a) Identification. A preformed tooth positioner is a plastic device that is an impression of a perfected...

  20. 21 CFR 872.3200 - Resin tooth bonding agent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Resin tooth bonding agent. 872.3200 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a) Identification. A resin tooth bonding agent is a device material, such as methylmethacrylate, intended to be...

  1. 21 CFR 872.5525 - Preformed tooth positioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Preformed tooth positioner. 872.5525 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5525 Preformed tooth positioner. (a) Identification. A preformed tooth positioner is a plastic device that is an impression of a perfected...

  2. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Preformed gold denture tooth. 872.3580 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of austenitic alloys or alloys containing...

  3. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Preformed gold denture tooth. 872.3580 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of austenitic alloys or alloys containing...

  4. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Preformed gold denture tooth. 872.3580 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of austenitic alloys or alloys containing...

  5. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Preformed gold denture tooth. 872.3580 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of austenitic alloys or alloys containing...

  6. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Preformed gold denture tooth. 872.3580 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of austenitic alloys or alloys containing...

  7. Successful pregnancy outcome after in vitro fertilisation following Pre-implantation Genetic Diagnosis/Polymerase Chain Reaction screening for single gene disorder (sickle cell anaemia) before embryo transfer: The clinical experience of an in vitro fertilisation clinic in Nigeria.

    PubMed

    Okeke, Chizara; Ailoje-Ibru, Kemi; Olukoya, Kemi; Ogbeche, Rose; Adewusi, Abiola; Iloabachie, Ebele; Ashiru, Oladapo

    2014-01-01

    A couple, both carriers of the sickle cell anaemia trait (Genotype HbAS) with an offspring already affected with the genetic disease underwent a Pre-implantation Genetic Diagnosis/Polymerase Chain Reaction screening of biopsied blastomeres. DNA analysis of single blastomeres was carried out to find out indicated a viable intra-uterine pregnancy with embryos which carried the sickle cell mutation, which resulted in a livebirth (HbAS). PGD/PCR in combination with IVF appears to be the most suitable treatment plan for patients who are at a higher risk of reproducing offspring affected with inheritable genetic diseases. PMID:24970979

  8. Neurologic Regulation and Orthodontic Tooth Movement.

    PubMed

    Kyrkanides, Stephanos; Huang, Hechang; Faber, Richard D

    2016-01-01

    Pain and discomfort are prevalent symptoms among the vast majority of patients with fixed orthodontic appliances and is the most disliked aspect of treatment. The periodontium is a highly innervated structure that also provides the necessary trophic factors, such as nerve growth factor, which promote neuronal survival, maintenance and axonal growth, via interaction with specific nerve surface receptors, such as TrkA. Various types of nerves are found in the periodontium, including thinly myelinated and unmyelinated sensory fibers that express the neuropeptides substance P and calcitonin gene-related peptide among others. Tooth movement activates peripheral sensory nerve endings, which transmit painful signals to the brain after being processed at the trigeminal spinal nucleus, resulting in local expression of pain related genes, such as c-Fos. Concurrently, an attendant inflammatory process is detected in the trigeminal spinal nucleus, including activation of astrocytes, microglia and neurons. This complex neurologic reaction to tooth movement mediates orthodontic pain and also serves a source of neurogenic inflammation exhibited in the trigeminal spinal nucleus and the periodontium. Activated periodontal sensory fibers release neuropeptides in the periodontal environment, which in turn induce a local inflammatory cascade aiding in alveolar bone turnover and tooth movement per se. Control of pain with nonsteroidal anti-inflammatory drugs and other prescription or over-the-counter pain killers effectively reduce this neurologic reaction and alleviate the attendant pain, but also reduce the neurogenic inflammatory component of orthodontic tooth movement causing a slowdown in bone turnover and consequently delaying orthodontic treatment. PMID:26599119

  9. Gastroesophageal Reflux Disease and Tooth Erosion

    PubMed Central

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

    2012-01-01

    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. PMID:22194748

  10. Computed tomography to quantify tooth abrasion

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

    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.

  11. Tooth wear: diet analysis and advice.

    PubMed

    Young, William George

    2005-04-01

    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

  12. Gear Tooth Root Stresses of a Very Heavily Loaded Gear Pair-Case Study: Orbiter Body Flap Actuator Pinion and Ring Gear

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy L.; Handschuh, Robert F.

    2015-01-01

    The space shuttle orbiter's body flap actuator gearing was assessed as a case study of the stresses for very heavily loaded external-internal gear pairs (meshing pinion and ring gear). For many applications, using the high point of single tooth contact (HPSTC) to locate the position of the tooth force is adequate for assessing the maximum tooth root stress condition. But for aerospace gearing such an approach may be inadequate for assessing the stress condition while also simultaneously minimizing mass. In this work specialized contact analyses and finite element methods were used to study gear tooth stresses of body flap actuator gears. The analytical solutions considered the elastic deformations as an inherent part of the solutions. The ratio for the maximum tooth stresses using the HPSTC approach solutions relative to the contact analysis and finite element solutions were 1.40 for the ring gear and 1.28 for the pinion gear.

  13. Anatomically guided implant site preparation technique at molar sites.

    PubMed

    Rodriguez-Tizcareo, Mario H; Bravo-Flores, Claudia

    2009-10-01

    Immediate postextraction implant placement in the areas of multiradicular teeth is a difficult procedure in view of having to place the implant in an ideal position without jeopardizing its initial stability. The surgeon often faces the problem of directing the initial osteotomy in the medial portion of the alveolus with the difficulty of engaging the inter-radicular septum of the extraction socket. The drill may slip continually leading to an inaccurate site preparation, and consequently to a deficient implant insertion. The fixture is often placed directly into either one of the extraction sockets of the tooth to be replaced. The anatomically guided site preparation technique is a very useful tool to perform implant placement in the areas of multiradicular teeth. This approach of implant insertion consists of a progressive preparation of the implant site using the anatomy and geometry of the root of the multiradicular teeth to be extracted as a reference and as an aid to engage the inter-radicular septum. This places the implants in a favorable and proper position from a biomechanical and occlusal standpoint. The objective of this article is to describe the anatomically guided implant site preparation technique as an aid to favorably place dental implants in multiradicular teeth postextraction. PMID:22129957

  14. [Biomechanical study on orthodontic tooth movement: changes in biomechanical property of the periodontal tissue in terms of tooth mobility].

    PubMed

    Inoue, Y

    1989-12-01

    The magnitude of tooth mobility has been frequently used for evaluating biomechanical response of the periodontal tissue to applied forces. However, tooth mobility during orthodontic tooth movement has not been measured. The purpose of this study was to investigate changes in biomechanical property of the periodontal tissue during canine retraction, in terms of tooth mobility. The upper canines on both sides of ten orthodontic patients were moved in the distal direction for about four weeks with an initial force of 200 gf. An amount of tooth movement and a magnitude of tooth mobility were measured every 3 or 4 days during retraction. A distally directed force up to 500 gf was continuously applied to each canine and tooth mobility was measured with a noncontact type of eddy current displacement sensor. A two-dimensional finite element model was constructed and displacements of the finite element model were calculated with various Young's moduli in loading with a 100 gf force in the distal direction. In comparison with the magnitudes of the tooth mobility, Young's modulus of the periodontal membrane before retraction and the influence of the biomechanical factors on changes in tooth mobility were investigated. The tooth movement curve was divided into three phases; an initial phase, a lag phase and a post-lag phase. The magnitudes of tooth mobility at the initial phase were significantly larger than those before retraction within the range of 250 gf to 500 gf and these magnitudes decreased during the lag phase. The magnitudes of tooth mobility at the post-lag phase significantly increased, within the range of 50 gf to 500 gf, than those before retraction. As a result of curveliniar regression analysis, the tooth mobility curves approximated to delta = AFB, where delta and F denote tooth mobility and force respectively. The coefficients A and B changed according to the phases of tooth movement. An inclination of the tooth mobility curve expressed by a tangent at the 400 gf force was the largest at the initial phase, and this inclination at the 100 gf force was the largest at the post-lag phase. Young's modulus of the periodontal membrane before retraction was determined to be approximately 35 gf/mm2 and Young's modulus of the periodontal membrane was the most important factor on the increase of tooth mobility. Tooth mobility significantly varied associated with tooth movement. It was indicated that biomechanical property of the periodontal tissue changes in response to each phase of tooth movement. In particular, Young's modulus of the periodontal membrane decreased at the post-lag phase of the orthodontic tooth movement. PMID:2488921

  15. Computer aided design and analysis of gear tooth geometry

    NASA Technical Reports Server (NTRS)

    Chang, S. H.; Huston, R. L.

    1987-01-01

    A simulation method for gear hobbing and shaping of straight and spiral bevel gears is presented. The method is based upon an enveloping theory for gear tooth profile generation. The procedure is applicable in the computer aided design of standard and nonstandard tooth forms. An inverse procedure for finding a conjugate gear tooth profile is presented for arbitrary cutter geometry. The kinematic relations for the tooth surfaces of straight and spiral bevel gears are proposed. The tooth surface equations for these gears are formulated in a manner suitable for their automated numerical development and solution.

  16. Maxillary implant-retained partial overdenture with Dolder bar attachment: a clinical report.

    PubMed

    Kim, Hyeongil; Buhite, Robert J; Monaco, Edward A

    2015-03-01

    This article describes a technique for maintaining a maxillary Kennedy III partial removable dental prosthesis design in a patient who had non-restorable failing abutments by replacing the abutments with dental implants. Two implants were placed immediately after extraction of the abutment teeth in the anterior maxilla. After the implants were fully integrated, a Dolder bar attachment was fitted onto the implants. A new maxillary partial removable dental prosthesis was fabricated using the implants and the remaining natural teeth as abutments to restore function and esthetics. With the aid of dental implants, this Kennedy III maxillary removable dental prosthesis design could provide additional retention and support by promoting cross-arch stability and tissue, implant and tooth support. The patient's satisfaction was significantly increased. PMID:25928972

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

    PubMed Central

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

    2013-01-01

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

  18. A model of growth restraints to explain the development and evolution of tooth shapes in mammals.

    PubMed

    Osborn, Jeffrey W

    2008-12-01

    The problem investigated here is control of the development of tooth shape. Cells at the growing soft tissue interface between the ectoderm and mesoderm in a tooth anlage are observed to buckle and fold into a template for the shape of the tooth crown. The final shape is created by enamel secreted onto the folds. The pattern in which the folds develop is generally explained as a response to the pattern in which genes are locally expressed at the interface. This congruence leaves the problem of control unanswered because it does not explain how either pattern is controlled. Obviously, cells are subject to Newton's laws of motion so that mechanical forces and constraints must ultimately cause the movements of cells during tooth morphogenesis. A computer model is used to test the hypothesis that directional resistances to growth of the epithelial part of the interface could account for the shape into which the interface folds. The model starts with a single epithelial cell whose growth is constrained by 4 constant directional resistances (anterior, posterior, medial and lateral). The constraints force the growing epithelium to buckle and fold. By entering into the model different values for these constraints the modeled epithelium is induced to buckle and fold into the different shapes associated with the evolution of a human upper molar from that of a reptilian ancestor. The patterns and sizes of cusps and the sequences in which they develop are all correctly reproduced. The model predicts the changes in the 4 directional constraints necessary to develop and evolve from one tooth shape into another. I conclude more generally expressed genes that control directional resistances to growth, not locally expressed genes, may provide the information for the shape into which a tooth develops. PMID:18838080

  19. Ligature-induced peri-implant infection in crestal and subcrestal implants: a clinical and radiographic study in dogs

    PubMed Central

    Huang, Baoxin; Piao, Muzi; Zhang, Li; Wang, Xian’e; Xu, Li; Zhu, Weidong

    2015-01-01

    Objective. The aim of this study was to assess the influence of implant–abutment interface (IAI) placement depths on peri-implant tissues in the presence of ligature-induced peri-implant inflammation. Materials and Methods. Two implants with screwed-in IAIs (SI) and two implants with tapped-in IAIs (TI) were inserted in one side of the mandible in six dogs eight weeks after tooth extraction. Four experimental groups were constituted: SI placed crestally, SI placed 1.5 mm subcrestally, TI placed crestally and TI placed 1.5 mm subcrestally. After 12 weeks, the healing abutments were connected. Four weeks later, cotton floss ligatures were placed around the abutments to promote plaque accumulation. Clinical and radiographic examinations were performed at 0, 6 and 12 weeks after ligature placement. The effects of the IAI placement depths on clinical and radiographic parameters were assessed. Results. The alterations of peri-implant probing depths, clinical attachment levels, distances from the IAI to the first bone-implant contact (IAI-fBIC) and depths of infrabony defect were significant larger in the subcrestal groups compared with the crestal groups during the plaque accumulation period. The alterations of clinical attachment levels, IAI-fBIC, depth of the infrabony defect and horizontal bone loss were not significantly different between the SI and TI groups after ligature placement. Conclusion. Tissue destruction in subcrestal implants may be more serious than that in crestal implants in the presence of inflamed peri-implant mucosa. PMID:26246975

  20. Transmaxillary osteogenic distraction with intraoral tooth-borne distractors.

    PubMed

    Margaride, Luis Alberto; Breuer, Jorge

    2012-09-01

    Midfacial retrusion and class III malocclusion in maxillary hypoplasia are frequent sequelae in patients with cleft lip and palate. Similar deformities are seen in craniofacial dysostosis surgically treated in infancy. Recurrences after orthognathic surgery are unpredictable even using rigid fixations. Distraction osteogenesis, using Le Fort I osteotomies with external distractors, is uncomfortable for the patient, and internal distractors require a second procedure for removing the retractor. A new model of distraction osteogenesis is presented. Transmaxillary osteogenic distraction, using tooth-borne devices, is a simple method and allows ambulatory retraction of distractors. Osteogenesis between molars and premolars at the alveolar level is stable and allows orthodontic mobilization and dental implants. Anchorage in molars and maxillary tuberosities avoids velopharyngeal incompetence. Transmaxillary osteogenic distraction techniques are described, as well as results after 7 years of experience in 45 patients with maxillary hypoplasia. Results are satisfactory and stable, surgery is simple, and custom-made intraoral devices are easy to handle with minimal discomfort for the patients. PMID:22948655

  1. Three ways to be a saber-toothed cat.

    PubMed

    Martin, L D; Babiarz, J P; Naples, V L; Hearst, J

    2000-01-01

    Saber-toothed carnivores, until now, have been divided into two groups: scimitar-toothed cats with shorter, coarsely serrated canines coupled with long legs for fast running, and dirk-toothed cats with more elongate, finely serrated canines coupled to short legs built for power rather than speed. In the Pleistocene of North America, as in Europe, the scimitar-cat was Homotherium; the North American dirk-tooth was Smilodon. We now describe a new sabercat from the Early Pleistocene of Florida, combining the scimitar-tooth canine with the short, massive limbs of a dirk-tooth predator. This presents a third way to construct a saber-toothed carnivore. PMID:10663132

  2. The evaluation of optimized implants for idealized implant geometries.

    PubMed

    Low, D A; Williamson, J F

    1995-09-01

    The purpose of this paper is to investigate the utility of implant quality measures on single stepping-source brachytherapy treatment plans. Four dwell weight optimization algorithms were applied to four regular geometric implants: single plane, double plane, cuboid, and cylindrical. The dwell weight optimization schemes included equal weighing, two commercial optimization schemes (dose-point and geometric) and a variation of the Paterson-Parker distribution rules. The implant quality measures were investigated as a function of dose-per-integrated reference air kerma (IRAK) to eliminate bias resulting from a prescription choice. A particular dose per IRAK refers to a dose surface that is a function only of the relative dwell weight distribution and is therefore well suited to investigate dwell weight optimization schemes. The implant quality measures included the dose-nonuniformity ratio (DNR) developed by Saw and a coverage index to assess the isodose coverage relative to the implanted volume. These were termed direct quantities due to their clear clinical significance. Additional measures include the ratio of the implant dose-volume histogram (DVH) to that of a point source exhibiting the same IRAK (Rp) and the ratio of the optimized DVH to the equally weighted DVH (EWR). The widths of the Rp curves and depths of the EWR curves were used to characterize these indirect implant quality measures. To evaluate the effectiveness of both the direct and indirect measures, they were correlated with the DNR for an isodose surface that covered the implant (D0). The efficiency of the dwell weight distribution was examined by noting the dose-per-IRAK surface D0.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8531878

  3. Paying for treatments? Influences on negotiating clinical need and decision-making for dental implant treatment

    PubMed Central

    Exley, Catherine E; Rousseau, Nikki S; Steele, Jimmy; Finch, Tracy; Field, James; Donaldson, Cam; Thomason, J Mark; May, Carl R; Ellis, Janice S

    2009-01-01

    Background The aim of this study is to examine how clinicians and patients negotiate clinical need and treatment decisions within a context of finite resources. Dental implant treatment is an effective treatment for missing teeth, but is only available via the NHS in some specific clinical circumstances. The majority of people who receive this treatment therefore pay privately, often at substantial cost to themselves. People are used to paying towards dental treatment costs. However, dental implant treatment is much more expensive than existing treatments such as removable dentures. We know very little about how dentists make decisions about whether to offer such treatments, or what patients consider when deciding whether or not to pay for them. Methods/Design Mixed methods will be employed to provide insight and understanding into how clinical need is determined, and what influences people's decision making processes when deciding whether or not to pursue a dental implant treatment. Phase 1 will use a structured scoping questionnaire with all the General dental practitioners (GDPs) in three Primary Care Trust areas (n = 300) to provide base-line data about existing practice in relation to dental implant treatment, and to provide data to develop a systematic sampling procedure for Phase 2. Phases 2 (GDPs) and 3 (patients) use qualitative focused one to one interviews with a sample of these practitioners (up to 30) and their patients (up to 60) to examine their views and experiences of decision making in relation to dental implant treatment. Purposive sampling for phases 2 and 3 will be carried out to ensure participants represent a range of socio-economic circumstances, and choices made. Discussion Most dental implant treatment is conducted in primary care. Very little information was available prior to this study about the quantity and type of treatment carried out privately. It became apparent during phase 2 that ISOD treatment was an unusual treatment in primary care. We thus extended our sample criteria for Phase 3 to include people who had had other implant supported restorations, although not single tooth replacements. PMID:19138389

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

    PubMed Central

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

    2013-01-01

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

  5. Clinical management of the avulsed tooth.

    PubMed

    Trope, M

    1995-01-01

    Treatment outside the dental office: Replant immediately after gentle washing if practical. If replantation is not practical, store the tooth in the best medium available. Storage media in order of preference are Hank's Balanced Salt Solution (HBSS), milk, saline, and saliva (buccal vestibule). Water is the least desirable storage medium. Treatment in the office: Emergency visit; Place tooth in HBSS while exam is conducted and history is taken. Prepare socket for gentle repositioning of the tooth. Prepare the root. Extraoral dry time < 20 minutes: Closed apex--replant immediately after gentle washing. Open apex--soak in 1 mg doxycycline in 20 mg saline for 5 minutes. Extraoral dry time 20 to 60 minutes: Soak in HBSS for 30 minutes and replant. Extraoral dry time > 60 minutes: soak in citric acid, 2% stannous fluoride, and doxycycline and replant. Endodontics can be done extraorally. Semirigid splint for 7 to 10 days. (If alveolar fracture is present, rigid splint for 4 to 8 weeks). Suture soft-tissue lacerations, particularly in the cervical area. Administer systemic antibiotics (penicillin V potassium if possible) Chlorhexidine rinses and stringent oral hygiene while the splint is in place (7 to 10 days). Analgesics as required. Second visit after 7 to 10 days: Endodontic treatment: Tooth with open apex and extraoral dry time of < 60 minutes: No endodontic treatment initially. Recall every 3 to 4 weeks to examine for evidence of pathosis. If pathosis is noted, disinfect the pulp space and start apexification procedure. Tooth with open apex and extraoral dry time > 60 minutes: If endodontics was not completed in the emergency visit, start endodontics and follow apexification procedure. Tooth with closed apex: Endodontics should be initiated after 7 to 10 days. Careful chemomechanical instrumentation under strict asepsis. Splint removed at end of visit. Obturation visit: If endodontics was initiated 7 to 10 days after the avulsion, obturation can take place after short-term calcium hydroxide treatment. If endodontics was initiated more than 14 days after the avulsion or inflammatory resorption, long-term calcium hydroxide for 6 to 24 months, obturated when an intact lamina dura is traced. Restorations: Temporary restorations: Should be 4 mm deep. Reinforced zinc-oxide-eugenol, acid-etch composite resin, glass-ionomer cement. Permanent restoration: Placed immediately after obturation. Acid-etch resin and dentin bonding agents. Follow-up care: Twice per year for 3 years and yearly for as long as possible. Late complications are common. PMID:7890110

  6. Patient-specific Analysis of Periodontal and Peri-implant Microbiomes

    PubMed Central

    Dabdoub, S.M.; Tsigarida, A.A.; Kumar, P.S.

    2013-01-01

    Periodontally involved teeth have been implicated as microbial reservoirs in the etiology of peri-implant diseases. Therefore, the purpose of this investigation was to use a deep-sequencing approach to identify the degree of congruence between adjacent peri-implant and periodontal microbiomes in states of health and disease. Subgingival and peri-implant biofilm samples were collected from 81 partially edentulous individuals with periodontal and peri-implant health and disease. Bacterial DNA was isolated, and the 16S rRNA gene was amplified and sequenced by pyrotag sequencing. Chimera-depleted sequences were compared against a locally hosted curated database for bacterial identification. Statistical significance was determined by paired Students t tests between tooth-implant pairs. The 1.9 million sequences identified represented 523 species. Sixty percent of individuals shared less than 50% of all species between their periodontal and peri-implant biofilms, and 85% of individuals shared less than 8% of abundant species between tooth and implant. Additionally, the periodontal microbiome demonstrated significantly higher diversity than the implant, and distinct bacterial lineages were associated with health and disease in each ecosystem. Analysis of our data suggests that simple geographic proximity is not a sufficient determinant of colonization of topographically distinct niches, and that the peri-implant and periodontal microbiomes represent microbiologically distinct ecosystems. PMID:24158341

  7. Three dimensional dental epithelial-mesenchymal constructs of predetermined size and shape for tooth regeneration.

    PubMed

    Zhang, Weibo; Ahluwalia, Ivy P; Yelick, Pamela C

    2010-11-01

    While it is known that precise dental epithelial-mesenchymal (DE-DM) cell interactions provide critical functions in tooth development, reliable methods to establish proper DE-DM cell interactions for tooth regeneration have yet to be established. To address this challenge, and to generate bioengineered teeth of predetermined size and shape, in this study, we characterize three dimensional (3D) pre-fabricated DE-DM cell constructs. Human dental pulp cell seeded Collagen gel layers were co-cultured with porcine DE cells suspended in Growth Factor Reduced (GFR) Matrigel. The resulting 3D DE-DM cell layers were cultured in vitro, or implanted and grown subcutaneously in vivo in nude rats. Molecular, histological and immunohistochemical (IHC) analyses of harvested implants revealed organized DE-DM cell interactions, the induced expression of dental tissue-specific markers Amelogenin (AM) and Dentin Sialophosphoprotein (DSPP), and basement membrane markers Laminin 5 and collagen IV, and irregular mineralized tissue formation after 4 weeks. We anticipate that these studies will facilitate the eventual establishment of reliable methods to elaborate dental tissues, and full sized teeth of specified sized and shape. PMID:20682455

  8. Ridge Preservation for Implant Therapy: a Review of the Literature

    PubMed Central

    Tomlin, Elizabeth M; Nelson, Shelby J; Rossmann, Jeffrey A

    2014-01-01

    Healing of the extraction socket after tooth removal involves retention of the blood clot followed by a sequence of events that lead to changes in the alveolar process in a three dimensional fashion. This normal healing event results in a minimal loss of vertical height (around 1 mm), but a substantial loss of width in the buccal-lingual plane (4-6 mm). During the first three months following extraction that loss has been shown to be significant and may result in both a hard tissue and soft tissue deformity affecting the ability to restore the site with acceptable esthetics. Procedures that reduce the resorptive process have been shown to be predictable and potentially capable of eliminating secondary surgery for site preparation when implant therapy is planned. The key element is prior planning by the dental therapist to act at the time of extraction to prevent the collapse of the ridge due to the loss of the alveolus. Several techniques have been employed as ridge preservation procedures involving the use of bone grafts, barrier membranes and biologics to provide a better restorative outcome. This review will explore the evidence behind each technique and their efficacy in accomplishing site preparation. The literature does not identify a single technique as superior to others; however, all accepted therapeutic procedures for ridge preservation have been shown to be more effective than blood clot alone in randomized controlled studies. PMID:24893595

  9. Implant site Nexplanon reaction?

    PubMed

    Pedroso, Célia; Martins, Isabel; Palma, Fátima; Machado, Ana Isabel

    2015-01-01

    Nexplanon (Schering-Plough Limited/Merck Sharp & Dohme Limited (MSD)) is a long active reversible contraceptive method that provides effective contraception for 3 years. It consists of a single, flexible, rod-shaped implant, containing 68 mg etonogestrel. It is 4 cm long, consists of an ethylene vinyl acetate copolymer, a non-absorbable material, and also contains 15 mg of barium sulfate, which makes it visible by X-ray. We describe a case of a 39-year-old woman who experienced a local reaction to the barium sulfate in Nexplanon. She was given medical treatment, but only the removal of the implant resolved the symptoms. After removal there was gradual improvement and 72 h later the patient was asymptomatic. Allergic reaction to barium sulfate is extremely rare: until now, there have only been two cases associated with Nexplanon described in the literature. PMID:25953577

  10. Histological evidence of osseointegration in human retrieved fractured hydroxyapatite-coated screw-type implants: a case report.

    PubMed

    Uehara, Toshio; Takaoka, Katsunori; Ito, Koichi

    2004-10-01

    Histological evidence of clinically successful dental implants is very rare. This case report presents histological evidence of osseointegration in human implants retrieved because of fractures at the connected portion between the abutments and fixtures due to a car accident. The duration of functional loading of the implants was 18 months. Two hydroxyapatite (HA)-coated screw-type implants were removed with part of the healthy bone from the mandibular left molar region. A block was prepared using cutting and grinding equipment to obtain a central section approximately 50 microm thick, which was stained with basic fuchsin and methylene blue. Histological examination revealed that the bone was dense and in close relation with the HA coating of the implants. The interspaces of each thread of the implant were filled with mineralized bone. Peri-implant soft tissue was not observed in the section. A high degree of osseointegration was noted, with a bone-to-implant contact of 87.5% (implant corresponding to tooth 36) and 97.4% (implant corresponding to tooth 37). The connection between the 30 and 50 microm HA coating and the metal was uniformly tight and constant. In conclusion, the histological evidence showed a high degree of osseointegration in two HA-coated screw-type dental implants retrieved after functional loading for 18 months. PMID:15355395

  11. Microsystems Technology for Retinal Implants

    NASA Astrophysics Data System (ADS)

    Weiland, James

    2005-03-01

    The retinal prosthesis is targeted to treat age-related macular degeneration, retinitis pigmentosa, and other outer retinal degenerations. Simulations of artificial vision have predicted that 600-1000 individual pixels will be needed if a retinal prosthesis is to restore function such as reading large print and face recognition. An implantable device with this many electrode contacts will require microsystems technology as part of its design. An implantable retinal prosthesis will consist of several subsystems including an electrode array and hermetic packaging. Microsystems and microtechnology approaches are being investigated as possible solutions for these design problems. Flexible polydimethylsiloxane (PDMS) substrate electrode arrays and silicon micromachined electrode arrays are under development. Inactive PDMS electrodes have been implanted in 3 dogs to assess mechanical biocompatibility. 3 dogs were followed for 6 months. The implanted was securely fastened to the retina with a single retinal tack. No post-operative complications were evident. The array remained within 100 microns of the retinal surface. Histological evaluation showed a well preserved retina underneath the electrode array. A silicon device with electrodes suspended on micromachined springs has been implanted in 4 dogs (2 acute implants, 2 chronic implants). The device, though large, could be inserted into the eye and positioned on the retina. Histological analysis of the retina from the spring electrode implants showed that spring mounted posts penetrated the retina, thus the device will be redesigned to reduce the strength of the springs. These initial implants will provide information for the designers to make the next generation silicon device. We conclude that microsystems technology has the potential to make possible a retinal prosthesis with 1000 individual contacts in close proximity to the retina.

  12. Simulated Single Tooth Bending of High Temperature Alloys

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert, F.; Burke, Christopher

    2012-01-01

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

  13. Reasons for permanent tooth extractions in Taiwan.

    PubMed

    Lee, Chen-Yi; Chang, Yong-Yuan; Shieh, Tien-Yu; Chang, Chin-Shun

    2015-03-01

    There has been no study in Taiwan on reasons for extraction of permanent teeth. This study aimed to determine the reasons for permanent teeth extraction in Taiwan. This study performed a secondary data analysis based on the National Health Insurance Research Database. The 2009 database was adopted and there are 131 104 records of dental visits in the database; among them, 4958 visits (from 4811 patients) have a coding of extraction. The results showed that dental caries (55.3%) was the main reason for tooth extraction, followed by periodontal disease (22.1%). Extraction because of dental caries was commonly observed in all age-groups, and extractions because of periodontal disease increased in those older than 35 years. Maxillary and mandibular third molar were the most frequently removed tooth types, and most were extracted because of dental caries and impaction respectively. PMID:22743854

  14. Aggregatibacter Actinomycetemcomitans – A Tooth Killer?

    PubMed Central

    Ummer, Fajar; Dhivakar, C.P

    2014-01-01

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

  15. New method of control of tooth whitening

    NASA Astrophysics Data System (ADS)

    Angelov, I.; Mantareva, V.; Gisbrecht, A.; Valkanov, S.; Uzunov, Tz.

    2010-10-01

    New methods of control of tooth bleaching stages through simultaneous measurements of a reflected light and a fluorescence signal are proposed. It is shown that the bleaching process leads to significant changes in the intensity of a scattered signal and also in the shape and intensity of the fluorescence spectra. Experimental data illustrate that the bleaching process causes essential changes in the teeth discoloration in short time as 8-10 min from the beginning of the application procedure. The continuation of the treatment is not necessary moreover the probability of the enamel destroy increases considerably. The proposed optical back control of tooth surface is a base for development of a practical set up to control the duration of the bleaching procedure.

  16. Tooth-colored CAD/CAM monolithic restorations.

    PubMed

    Reich, S

    2015-01-01

    A monolithic restoration (also known as a full contour restoration) is one that is manufactured from a single material for the fully anatomic replacement of lost tooth structure. Additional staining (followed by glaze firing if ceramic materials are used) may be performed to enhance the appearance of the restoration. For decades, monolithic restoration has been the standard for inlay and partial crown restorations manufactured by both pressing and computer-aided design and manufacturing (CAD/CAM) techniques. A limited selection of monolithic materials is now available for dental crown and bridge restorations. The IDS (2015) provided an opportunity to learn about and evaluate current trends in this field. In addition to new developments, established materials are also mentioned in this article to complete the picture. In line with the strategic focus of the IJCD, the focus here is naturally on CAD/CAM materials. PMID:26110926

  17. Orthodontic Tooth Movement with Clear Aligners

    PubMed Central

    Drake, Carl T.; McGorray, Susan P.; Dolce, Calogero; Nair, Madhu; Wheeler, Timothy T.

    2012-01-01

    Clear aligners provide a convenient model to measure orthodontic tooth movement (OTM). We examined the role of in vivo aligner material fatigue and subject-specific factors in tooth movement. Fifteen subjects seeking orthodontic treatment at the University of Florida were enrolled. Results were compared with data previously collected from 37 subjects enrolled in a similar protocol. Subjects were followed prospectively for eight weeks. An upper central incisor was programmed to move 0.5?mm. every two weeks using clear aligners. A duplicate aligner was provided for the second week of each cycle. Weekly polyvinyl siloxane (PVS) impressions were taken, and digital models were fabricated to measure OTM. Initial and final cone beam computed tomography (CBCT) images were obtained to characterize OTM. Results were compared to data from a similar protocol, where subjects received a new aligner biweekly. No significant difference was found in the amount of OTM between the two groups, with mean total OTM of 1.11?mm. (standard deviation (SD) 0.30) and 1.07?mm. (SD 0.33) for the weekly aligner and biweekly control groups, respectively (P = 0.72). Over eight weeks, in two-week intervals, material fatigue does not play a significant role in the rate or amount of tooth movement. PMID:22928114

  18. Mechanics analysis of molar tooth splitting.

    PubMed

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

    2015-03-01

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

  19. Iatrogenic traumatic brain injury during tooth extraction.

    PubMed

    Troxel, Mark

    2015-01-01

    An 8 yr old spayed female Yorkshire terrier was referred for evaluation of progressive neurological signs after a routine dental prophylaxis with tooth extractions. The patient was circling to the left and blind in the right eye with right hemiparesis. Neurolocalization was to the left forebrain. MRI revealed a linear tract extending from the caudal oropharynx, through the left retrobulbar space and frontal lobe, into the left parietal lobe. A small skull fracture was identified in the frontal bone through which the linear tract passed. Those findings were consistent with iatrogenic trauma from slippage of a dental elevator during extraction of tooth 210. The dog was treated empirically with clindamycin. The patient regained most of its normal neurological function within the first 4 mo after the initial injury. Although still not normal, the dog has a good quality of life. Traumatic brain injury is a rarely reported complication of extraction. Care must be taken while performing dental cleaning and tooth extraction, especially of the maxillary premolar and molar teeth to avoid iatrogenic damage to surrounding structures. PMID:25695556

  20. Influence of musical instruments on tooth positions.

    PubMed

    Herman, E

    1981-08-01

    A 2-year longitudinal investigation was conducted at five New York City junior high schools on 11- to 13-year-old children starting instrumental music education to determine what tooth movement, if any, resulted from the playing of certain musical instruments. Questionnaires, interviews, oral examinations, and dental casts were used at the start of instrumental study, after one year, and then after a second year. Statistically significant anterior tooth movements occurred in an overwhelming majority of the instrumentalists, while negligible movements were recorded for the controls over this period. As a result of this study, certain recommendations can be made by dentists when they are asked to suggest instruments which are dentally suited for children. In most cases they can suggest more than one instrument which would be of benefit dentally to the individual child, especially in the increase or reduction of overjet and overbite. The playing of the correct musical instrument can serve as an adjunct to the dentist or orthodontist in trying to accomplish certain tooth movements. PMID:6943935

  1. The impact of implant treatment on oral health related quality of life in a private dental practice: a prospective cohort study

    PubMed Central

    2013-01-01

    Background Very few studies on the impact of implant therapy on Oral Health Related Quality of Life (OHRQoL) in partially edentulous patients have been published. Aim This study aimed at analysing the improvement of OHRQoL of patients who underwent dental implant treatment using the functional, psychosocial and pain and discomfort categories of the Geriatric Oral Health Assessment Index (GOHAI). Methods Within a prospective cohort of patients rehabilitated with Straumann dental implants, the OHRQoL of 176 patients (104 women and 72 men) was assessed using the GOHAI questionnaire, at two different times, before and after implant placement. The degree of oral treatment was categorised into three classes: Single Tooth Implant (n?=?77), Fixed Partial Denture (n?=?75), Fixed or Retained Full Prostheses (n?=?24). The participants characteristics (gender, age, tobacco habits, periodontal treatment, time between both evaluations) were assessed. Results Before treatment, the GOHAI score was lower for participants with fewer teeth (F?=?19, P?Implants enhanced the OHRQoL of participants that needed oral treatment. PMID:24229381

  2. Should patients with implantable cardioverter-defibrillators be allowed to drive? Observations in 291 patients from a single center over an 11-year period.

    PubMed

    Trappe, H J; Wenzlaff, P; Grellman, G

    1998-06-01

    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 of the 291 patients had never driven. Of the remaining 241 patients, 171 (59%) continued driving postimplant and 70 (24%) elected to stop prior to (n = 30) or at the time of ICD implantation (n = 40). Patients were followed for a mean of 38 +/- 26 months (range < 1-124). During this period, no patients died while driving. Of 11 accidents involving 11 driving patients (6%), only 1 was caused by the driver, and none was related to syncopal symptoms or ICD therapy. Although 2 accidents (8%) occurred within 12 months postimplant, the majority (50%) took place after more than 36 months. ICD therapy was delivered in 8 patients (5%) while driving: 13% (1 episode) of the discharges occurred within the first year postimplant, 13% (1 episode) occurred between 1-2 years, and 74% (6 episodes) occurred > 2 years. None of these patients experienced syncope before or during these episodes. A multivariate analysis was unable to identify any variables that might predict increased risk of ICD therapy (with or without sudden death) while driving and consequent motor vehicle accidents. Our data suggest that such events occur only rarely. PMID:9870013

  3. Treatment options of untreatable traumatized anterior maxillary teeth for future use of dental implantation.

    PubMed

    Schwartz-Arad, Devorah; Levin, Liran; Ashkenazi, Malka

    2004-03-01

    The anterior maxilla is the most traumatized region during childhood. Posttraumatic complications occasionally lead to tooth loss as well as the need for future implants. Unfortunately, it is contraindicated to place dental implants during childhood. A waiting period of approximately 8 to 10 years before completion of growth is required. For this patient to become a candidate for future dental implants, it is necessary to ensure the continuous growth and to preserve the dimensions of the alveolar process until growth has ceased from time of injury until joint maturation. To achieve these goals, it is essential to coordinate the treatment sequence at the time of trauma. After loss of a traumatized anterior permanent maxillary incisor in young adults, treatment options are limited: orthodontic closure of the gap and reshaping the adjacent teeth, or tooth extraction and maintaining the gap with a temporary restoration. Orthodontic space closure has limited indications and requires prosthetic restoration of at least 2 teeth. Extraction and temporary restoration will usually lead to bone augmentation before implantation. Other possible treatment options include orthodontic extrusion of the root remnant (in cases of untreatable root fracture or complicated crown-root fracture) and a temporary crown to serve the patient until the completion of growth and development, autogenous tooth transplantation, intentional extraction and immediate tooth replantation, distraction osteogenesis, and decoronation. Because general rules do not apply, individual treatment plans are necessary. PMID:15017299

  4. Treatment options of untreatable traumatized anterior maxillary teeth for future use of dental implantation.

    PubMed

    Schwartz-Arad, Devorah; Levin, Liran; Ashkenazi, Malka

    2004-06-01

    The anterior maxilla is the most traumatized region during childhood. Posttraumatic complications occasionally lead to tooth loss as well as the need for future implants. Unfortunately, it is contraindicated to place dental implants during childhood. A waiting period of approximately 8 to 10 years before completion of growth is required. For this patient to become a candidate for future dental implants, it is necessary to ensure the continuous growth and to preserve the dimensions of the alveolar process until growth has ceased from time of injury until joint maturation. To achieve these goals, it is essential to coordinate the treatment sequence at the time of trauma. After loss of a traumatized anterior permanent maxillary incisor in young adults, treatment options are limited: orthodontic closure of the gap and reshaping the adjacent teeth, or tooth extraction and maintaining the gap with a temporary restoration. Orthdontic space closure has limited indications and requires prosthetic restoration of at least 2 teeth. Extraction and temporary restoration will usually lead to bone augmentation before implantation. Other possible treatment options include orthodontic extrusion of the root remnant (in cases of untreatable root fracture or complicated crown-root fracture) and a temporary crown to serve the patient until the completion of growth and development, autogenous tooth transplantation, intentional extraction and immediate tooth replantation, distraction osteogenesis, and decoronation. Because general rules do not apply, individual treatment plans are necessary. PMID:15179087

  5. Personality Style in Patients Looking for Tooth Bleaching and Its Correlation with Treatment Satisfaction.

    PubMed

    Martin, Javier; Rivas, Vanessa; Vildósola, Patricio; Moncada, Laura; Oliveira Junior, Osmir B; Saad, José Roberto C; Fernandez, Eduardo; Moncada, Gustavo

    2016-02-01

    In the last years the focus in dentistry has shifted to an "esthetic dentistry" approach, where patients are concerned about reaching a better look of their teeth. Vital tooth bleaching is a technique with immediate results, which improves the appearance and patient's self-esteem. The aim of this study was to recognize personality characteristics determined by the Millon Index of Personality Styles of participants looking for tooth bleaching and to correlate them to satisfaction with the treatment. Forty participants were included and filled out the Millon Index of Personality Styles form before treatment. Expectation about tooth bleaching was quantified from 1 to 5. Patients were treated with bleaching agent according to manufacturer's directions. One week after treatment, the patient's satisfaction was quantified from 1 to 5. Prevailing personality characteristics were determined. Expectations and satisfaction values of all patients were correlated with each of the presented personality scales by Spearman Rho test. Ten scales prevailed over their counterpart. Median of patient's expectation was 2 and satisfaction 4. Only the score of a single characteristic (extraversing) showed statistically significant correlation with patient satisfaction. Patients looking for tooth bleaching treatment seem to have common personality characteristics. Almost all of them wanted to achieve a moderate change in teeth color and the result of the treatment was usually satisfactory. PMID:27007348

  6. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    NASA Astrophysics Data System (ADS)

    Aragno, D.; Fattibene, P.; Onori, S.; Aragno, D.; Fattibene, P.

    2000-09-01

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO2- signal of intensity similar to that induced by a dose of about 2 mGy of 60Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined.

  7. Decaborane implantation with the medium current implanter

    NASA Astrophysics Data System (ADS)

    Hamamoto, Nariaki; Umisedo, Sei; Nagayama, Tsutomu; Tanjyo, Masayasu; Sakai, Shigeki; Nagai, Nobuo; Aoyama, Takayuki; Nara, Yasuo

    2005-08-01

    A decaborane implantation system has been developed. The maximum beam current achieved at a wafer is 30 ?A at 5 keV with the divergence less than 0.4, which corresponds to the equivalent 500 eV-300 ?A boron monomer implantation without an energy contamination. As-implanted secondary ion mass spectroscopy (SIMS) profile of the decaborane implanted at the equivalent energy 500 eV shows the steeper and shallower profile than that of the boron implanted. The result of Rs-Xj proves the higher activation with shallower junction depth. These advantages possibly arise from the self-amorphization layer by the decaborane implantation.

  8. Generation of spiral bevel gears with conjugate tooth surfaces and tooth contact analysis

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Tsung, Wei-Jiung; Lee, Hong-Tao

    1987-01-01

    A new method for generation of spiral bevel gears is proposed. The main features of this method are as follows: (1) the gear tooth surfaces are conjugated and can transform rotation with zero transmission errors; (2) the tooth bearing contact is localized; (3) the center of the instantaneous contact ellipse moves in a plane that has a fixed orientation; (4) the contact normal performs in the process of meshing a parallel motion; (5) the motion of the contact ellipse provides improved conditions of lubrication; and (6) the gears can be manufactured by use of Gleason's equipment.

  9. Auditory Midbrain Implant: A Review

    PubMed Central

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

    2009-01-01

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

  10. Efficacy of Nonthermal Atmospheric Pressure Plasma for Tooth Bleaching

    PubMed Central

    Nam, Seoul Hee; Lee, Hae June; Hong, Jin Woo; Kim, Gyoo Cheon

    2015-01-01

    The conventional light source used for tooth bleaching has the potential to cause thermal damage, and the actual role of the light source is doubtful. In this study, we evaluated bleaching efficacy, temperature, and morphological safety after tooth bleaching with nonthermal atmospheric pressure plasma. Tooth bleaching combined with plasma had improved efficacy in providing a higher level of brightness. The temperature of the pulp chamber was maintained around 37°C, indicating that the plasma does not cause any thermal damage. The morphological results of tooth bleaching with plasma did not affect mineral composition under scanning electron microscopy (SEM) observations. On the basis of these results, the application of plasma and low concentration of 15% carbamide peroxide (CP) has a high capability for effective tooth bleaching. It can be documented that plasma is a safe energe source, which has no deleterious effects on the tooth surface. PMID:25685843

  11. Implantable Cardioverter Defibrillator

    MedlinePLUS

    ... NHLBI on Twitter. What Is an Implantable Cardioverter Defibrillator? An implantable cardioverter defibrillator (ICD) is a small ... pacemakers and defibrillators. Comparison of an Implantable Cardioverter Defibrillator and a Pacemaker The image compares an ICD ...

  12. Implantable Cardioverter Defibrillator

    MedlinePLUS

    ... Implantable Cardioverter De... Back to Treatment Implantable Cardioverter Defibrillator Defibrillation , or shock, can be the only way ... arrest ( SCA ). What is an ICD ? Implantable cardioverter defibrillators ( ICDs ) are used to detect dangerously fast heartbeats ...

  13. Cranioplasty after decompressive craniectomy: is there a rationale for an initial artificial bone-substitute implant? A single-center experience after 631 procedures.

    PubMed

    Schwarz, Falko; Dnisch, Pedro; Walter, Jan; Sakr, Yasser; Kalff, Rolf; Ewald, Christian

    2016-03-01

    OBJECT The complication rate for cranioplasty after decompressive craniectomy is higher than that after other neurosurgical procedures; aseptic bone resorption is the major long-term problem. Patients frequently need additional operations to remove necrotic bone and replace it with an artificial bone substitute. Initial implantation of a bone substitute may be an option for selected patients who are at risk for bone resorption, but this cohort has not yet been clearly defined. The authors' goals were to identify risk factors for aseptic bone flap necrosis and define which patients may benefit more from an initial bone-substitute implant than from autograft after craniectomy. METHODS The authors retrospectively analyzed 631 cranioplasty procedures (503 with autograft, 128 with bone substitute) by using a stepwise multivariable logistic regression model and discrimination analysis. RESULTS There was a significantly higher risk for reoperation after placement of autograft than after placement of bone substitute; aseptic bone necrosis (n = 108) was the major problem (OR 2.48 [95% CI1.11-5.51]). Fragmentation of the flap into 2 or more fragments, younger age (OR 0.97 [95% CI 0.95-0.98]; p < 0.001), and shunt-dependent hydrocephalus (OR 1.73 [95% CI1.02-2.92]; p = 0.04) were independent risk factors for bone necrosis. According to discrimination analysis, patients younger than 30 years old and older patients with a fragmented flap had the highest risk of developing bone necrosis. CONCLUSIONS Development of bone flap necrosis is the main concern in long-term follow-up after cranioplasty with autograft. Patients younger than 30 years old and older patients with a fragmented flap may be candidates for an initial artificial bone substitute rather than autograft. PMID:26406796

  14. Insights on Metal Based Dental Implants and their Interaction with the Surrounding Tissues.

    PubMed

    Popa, Marcela; Hussien, Mohamed D; Cirstea, Alexandra; Grigore, Raluca; Lazar, Veronica; Bezirtzoglou, Eugenia; Chifiriuc, Mariana Carmen; Sakizlian, Monica; Stavropoulou, Elisavet; Bertesteanu, Serban

    2015-01-01

    At present, the use of dental implants is a very common practice as tooth loss is a frequent problem and can occur as a result of disease or trauma. An implant is usually made of biocompatible materials that do not cause rejection reactions and allow the implant union with the respective bone. To achieve this goal, the implant surface may have different structures and coatings, generally used to increase the adherence of the implant to the bone and to decrease the risk of the periimplantar inflammatory reactions. This review gives some insights of the metal based materials used for dental implants, their limits, improvement strategies as well as the pathophysiology, diagnosis, treatment and prevention of periimplantary diseases. PMID:25877088

  15. Computer aided design of bevel gear tooth surfaces

    NASA Technical Reports Server (NTRS)

    Chang, S. H.; Huston, R. L.; Coy, J. J.

    1989-01-01

    This paper presents a computer-aided design procedure for generating bevel gears. The development is based on examining a perfectly plastic, cone-shaped gear blank rolling over a cutting tooth on a plane crown rack. The resulting impression on the plastic gear blank is the envelope of the cutting tooth. This impression and envelope thus form a conjugate tooth surface. Equations are presented for the locus of points on the tooth surface. The same procedures are then extended to simulate the generation of a spiral bevel gear. The corresponding governing equations are presented.

  16. Computer-aided design of bevel gear tooth surfaces

    NASA Technical Reports Server (NTRS)

    Shuo, Hung Chang; Huston, Ronald L.; Coy, John J.

    1989-01-01

    This paper presents a computer-aided design procedure for generating bevel gears. The development is based on examining a perfectly plastic, cone-shaped gear blank rolling over a cutting tooth on a plane crown rack. The resulting impression on the plastic gear blank is the envelope of the cutting tooth. This impression and envelope thus form a conjugate tooth surface. Equations are presented for the locus of points on the tooth surface. The same procedures are then extended to simulate the generation of a spiral bevel gear. The corresponding governing equations are presented.

  17. Tooth positioners and their effects on treatment outcome

    PubMed Central

    Pravindevaprasad, A.; Therese, Beena Agnes

    2013-01-01

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

  18. A panorama of tooth wear during the medieval period.

    PubMed

    Esclassan, Rémi; Hadjouis, Djillali; Donat, Richard; Passarrius, Olivier; Maret, Delphine; Vaysse, Frédéric; Crubézy, Eric

    2015-01-01

    Tooth wear is a natural phenomenon and a universal occurrence that has existed from the origin of humankind and depends on the way of life, especially diet. Tooth wear was very serious in ancient populations up to the medieval period. The aim of this paper is to present a global view of tooth wear in medieval times in Europe through different parameters: scoring systems, quantity and direction of wear, gender, differences between maxilla and mandible, relations with diet, caries, tooth malpositions and age. PMID:25807388

  19. Implant bone integration importance in forensic identification.

    PubMed

    De Angelis, Danilo; Cattaneo, Cristina

    2015-03-01

    Odontological identification consists of the comparison of antemortem dental information regarding a missing person with postmortem data from an unidentified corpse or human remains. Usually, the comparison concerns morphologic features that the operator chooses among all the visible characteristics because of inter-individual uniqueness; for this reason, implants can be of enormous assistance. A case concerning the recovery of a burnt oral implant, connected to a bone fragment, among 2780 charred bone fragments, suspected to have belonged to a victim of homicide, is presented to demonstrate that dental implants and their site of bone integration represent a very precious element for personal forensic identification. Because of their morphological invariability in time and because of their morphologic uniqueness, they were used as evidence to associate unidentified human charred remains to a missing person where DNA analysis failed to do so. The case illustrates the fundamental contribution, not yet described in literature, given by the clinical aspects of tooth replacement with dental implants to a forensic discipline. Clinical practitioners should therefore be aware of the great importance of their work and of dental records in a forensic identification scenario. PMID:25387697

  20. A 5-year randomized trial to compare 1 or 2 implants for implant overdentures.

    PubMed

    Bryant, S R; Walton, J N; MacEntee, M I

    2015-01-01

    The hypothesis of this 5-y randomized clinical trial was that there would be no significant difference in the satisfaction of edentulous participants with removable complete overdentures attached to 1 or 2 mandibular implants. Secondary aims were to test changes in satisfaction between and within the groups from baseline to 5 y and differences between the groups in implant survival and prosthodontic maintenance over 5 y. Each of the 86 participants (mean age, 67 y) was randomly allocated to receive either 1 implant in the midline (group 1) or 2 implants in the canine areas (group 2) attached to a mandibular overdenture opposing a maxillary complete denture. Satisfaction was self-assessed by participants on a visual analog scale at baseline prior to implants, as well as at 2 mo and 1, 3, and 5 y with implant overdentures, whereas implant survival and prosthodontic maintenance were assessed by clinical examination. After 5 y, 29 participants in group 1 and 33 in group 2 were available, with most dropouts due to death. Satisfaction with the implant denture after 5 y was significantly (P < 0.001) higher than at baseline in both groups and remained with no significant difference (P = 0.32) between the groups. No implants failed in group 1 but 5 failed before loading in 4 participants in group 2. Most participants required maintenance or occasionally denture replacement, and although differences between the groups were not statistically significant, group 1 experienced almost twice as many fractured dentures usually adjacent to the implant attachment. We conclude that there were no significant differences after 5 y in satisfaction or survival of implants with mandibular overdentures retained by 1 implant or 2 implants. Additional research is required to confirm long-term treatment effectiveness of single-implant dentures and the implications of prosthetic maintenance with implant overdentures (ClinicalTrials.gov: NCT02117856). PMID:25348544

  1. Magnesium stable isotope ecology using mammal tooth enamel

    PubMed Central

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2015-01-01

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages. PMID:25535375

  2. Magnesium stable isotope ecology using mammal tooth enamel.

    PubMed

    Martin, Jeremy E; Vance, Derek; Balter, Vincent

    2015-01-13

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ(13)C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ(44)Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ(26)Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ(26)Mg, δ(13)C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ(26)Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this (26)Mg enrichment up the trophic chain is due to a (26)Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ(26)Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ(26)Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages. PMID:25535375

  3. Development and Evolution of Dentition Pattern and Tooth Order in the Skates And Rays (Batoidea; Chondrichthyes)

    PubMed Central

    Underwood, Charlie J.; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J.; Fraser, Gareth J.; Smith, Moya Meredith

    2015-01-01

    Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the general plesiomorphic vertebrate dental condition. PMID:25874547

  4. CHIPPING FRACTURE RESISTANCE OF DENTURE TOOTH MATERIALS

    PubMed Central

    Quinn, G. D.; Giuseppetti, A. A.; Hoffman, K. H.

    2014-01-01

    Objective The applicability of the edge chipping method to denture tooth materials was assessed. These are softer materials than those usually tested by edge chipping. The edge chipping fracture resistances of polymethylmethacrylate (PMMA) based and two filled resin composite denture tooth materials were compared. Methods An edge chipping machine was used to chip rectangular blocks and flattened anterior denture teeth. Force versus edge distance data were collected over a broad range of forces and distances. Between 20 and 65 chips were made per condition depending upon the material, the scatter, and the indenter type. Different indenter types were used including Rockwell C, sharp conical 120°, Knoop, and Vickers. The edge toughness, Te, was evaluated for different indenter types. Results The edge chipping data collected on the blocks matched the data collected from flattened teeth. High scatter, particularly at large distances and loads, meant that many tests (up to 64) were necessary to compare the denture tooth materials and to ascertain the appropriate data trends. A linear force – distance trend analysis was adequate for comparing these materials. A power law trend might be more appropriate, but the large scatter obscured the definitive determination of the precise trend. Different indenters produce different linear trends, with the ranking of: sharp conical 120°, Rockwell C, and Knoop, from lowest to highest edge toughness. Vickers indenter data were extremely scattered and a sensible trend could not be obtained. Edge toughness was inversely correlated to hardness. Significance Edge chipping data collected either from simple laboratory scale test blocks or from actual denture teeth may be used to evaluate denture materials. The edge chipping method’s applicability has been extended to another class of restorative materials. PMID:24674342

  5. Gene Expression Profiling during Murine Tooth Development

    PubMed Central

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

    2012-01-01

    The aim of this study was to describe the expression of genes, including ameloblastin (Ambn), amelogenin X chromosome (Amelx), and enamelin (Enam) during early (pre-secretory) tooth development. The expression of these genes has predominantly been studied at post-secretory stages. Deoxyoligonucleotide microarrays were used to study gene expression during development of the murine first molar tooth germ at 24?h intervals, starting at the 11th embryonic day (E11.5), and up to the 7th day after birth (P7). The profile search function of Spotfire software was used to select genes with similar expression profile as the enamel genes (Ambn, Amelx, and Enam). Microarray results where validated using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR), and translated proteins identified by Western-blotting. In situ localization of the Ambn, Amelx, and Enam mRNAs were monitored from E12.5 to E17.5 using deoxyoligonucleotide probes. Bioinformatics analysis was used to associate biological functions with differentially expressed (DE; p???0.05) genes. Microarray results showed a total of 4362 genes including Ambn, Amelx, and Enam to be significant DE throughout the time-course. The expression of the three enamel genes was low at pre-natal stages (E11.5P0) increasing after birth (P1P7). Profile search lead to isolation of 87 genes with significantly similar expression to the three enamel proteins. These mRNAs were expressed in dental epithelium and epithelium derived cells. Although expression of Ambn, Amelx, and Enam were lower during early tooth development compared to secretory stages enamel proteins were detectable by Western-blotting. Bioinformatic analysis associated the 87 genes with multiple biological functions. Around 35 genes were associated with 15 transcription factors. PMID:22866057

  6. Epithelial topography for repetitive tooth formation

    PubMed Central

    Gaete, Marcia; Fons, Juan Manuel; Popa, Elena Mădălina; Chatzeli, Lemonia; Tucker, Abigail S.

    2015-01-01

    ABSTRACT During the formation of repetitive ectodermally derived organs such as mammary glands, lateral line and teeth, the tissue primordium iteratively initiates new structures. In the case of successional molar development, new teeth appear sequentially in the posterior region of the jaw from Sox2+ cells in association with the posterior aspect of a pre-existing tooth. The sequence of molar development is well known, however, the epithelial topography involved in the formation of a new tooth is unclear. Here, we have examined the morphology of the molar dental epithelium and its development at different stages in the mouse in vivo and in molar explants. Using regional lineage tracing we show that within the posterior tail of the first molar the primordium for the second and third molar are organized in a row, with the tail remaining in connection with the surface, where a furrow is observed. The morphology and Sox2 expression of the tail retains characteristics reminiscent of the earlier stages of tooth development, such that position along the A-P axes of the tail correlates with different temporal stages. Sox9, a stem/progenitor cell marker in other organs, is expressed mainly in the suprabasal epithelium complementary with Sox2 expression. This Sox2 and Sox9 expressing molar tail contains actively proliferating cells with mitosis following an apico-basal direction. Snail2, a transcription factor implicated in cell migration, is expressed at high levels in the tip of the molar tail while E-cadherin and laminin are decreased. In conclusion, our studies propose a model in which the epithelium of the molar tail can grow by posterior movement of epithelial cells followed by infolding and stratification involving a population of Sox2+/Sox9+ cells. PMID:26538639

  7. Nasopharyngeal tooth foreign body in a dog.

    PubMed

    Kang, Min-Hee; Lim, Chae-Young; Park, Hee-Myung

    2011-01-01

    An 8-year-old Shih-tzu dog was presented with a 2-week history of cough and nasal discharge. Upon presentation, the dog had constant open-mouth breathing with stertor and blood-tinged mucopurulent nasal discharge. Oral examination revealed a missing right mandibular second premolar tooth and severe periodontal disease. Computed tomography showed a radiodense, retropharyngeal foreign body. The foreign body was removed using caudal rhinoscopy. The foreign body was the right mandibular second premolar covered by thick calculus. PMID:21696125

  8. Measurement of Gear Tooth Dynamic Friction

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  9. Femur, rib, and tooth sample collection for DNA analysis in disaster victim identification (DVI) : a method to minimize contamination risk.

    PubMed

    Westen, Antoinette A; Gerretsen, Reza R R; Maat, George J R

    2008-01-01

    Although much literature is available on DNA extraction from tissue samples to obtain the best possible genotyping results, to the best of our knowledge no written recommendations exist on how to excise or extract bone and tooth samples from a victim to facilitate this. Because the possibility of cross-contamination is high, especially when excising numerous samples under disaster conditions, it is important to minimize this risk and to keep samples in optimum condition. In this paper a standard operating procedure is proposed for collection of femur, rib, and tooth samples to aid victim identification both after mass disasters and in (single) forensic investigations. PMID:19291465

  10. Selection and modification of prefabricated implant abutments according to the desired restoration contour: a case report.

    PubMed

    Kourtis, Stefanos G

    2002-05-01

    Implant restorations must fulfill the functional and esthetic demands of the patient. The discrepancy in the diameters of an implant and a natural tooth often leads to compromise. The use of prefabricated abutments that can be individually modified offers certain advantages. Selection and modification of the abutment are simpler when a waxup of the restoration is used as a guideline. This article describes a laboratory technique in which the implant abutment is selected and modified according to the waxup of the restoration. PMID:12014169

  11. Bone marrow-derived stromal cells are more beneficial cell sources for tooth regeneration compared with adipose-derived stromal cells.

    PubMed

    Ye, Lanfeng; Chen, Lin; Feng, Fan; Cui, Junhui; Li, Kaide; Li, Zhiyong; Liu, Lei

    2015-10-01

    Tooth loss is presently a global epidemic and tooth regeneration is thought to be a feasible and ideal treatment approach. Choice of cell source is a primary concern in tooth regeneration. In this study, the odontogenic differentiation potential of two non-dental-derived stem cells, adipose-derived stromal cells (ADSCs) and bone marrow-derived stromal cells (BMSCs), were evaluated both in vitro and in vivo. ADSCs and BMSCs were induced in vitro in the presence of tooth germ cell-conditioned medium (TGC-CM) prior to implantation into the omentum majus of rats, in combination with inactivated dentin matrix (IDM). Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA expression levels of odontogenic-related genes. Immunofluorescence and immunohistochemical assays were used to detect the protein levels of odontogenic-specific genes, such as DSP and DMP-1 both in vitro and in vivo. The results suggest that both ADSCs and BMSCs have odontogenic differentiation potential. However, the odontogenic potential of BMSCs was greater compared with ADSCs, showing that BMSCs are a more appropriate cell source for tooth regeneration. PMID:25965323

  12. Common developmental pathways link tooth shape to regeneration

    PubMed Central

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

    2013-01-01

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

  13. The combination use of platelet-rich fibrin and treated dentin matrix for tooth root regeneration by cell homing.

    PubMed

    Ji, Baohui; Sheng, Lei; Chen, Gang; Guo, Shujuan; Xie, Li; Yang, Bo; Guo, Weihua; Tian, Weidong

    2015-01-01

    Endogenous regeneration through cell homing provides an alternative approach for tissue regeneration, except cell transplantation, especially considering clinical translation. However, tooth root regeneration through cell homing remains a provocative approach in need of intensive study. Both platelet-rich fibrin (PRF) and treated dentin matrix (TDM) are warehouses of various growth factors, which can promote cell homing. We hypothesized that endogenous stem cells are able to sense biological cues from PRF membrane and TDM, and contribute to the regeneration of tooth root, including soft and hard periodontal tissues. Therefore, the biological effects of canine PRF and TDM on periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMSCs) were evaluated respectively in vitro. Beagle dogs were used as orthotopic transplantation model. It was found that PRF significantly recruited and stimulated the proliferation of PDLSCs and BMSCs in vitro. Together, PRF and TDM induced cell differentiation by upregulating the mineralization-related gene expression of bone sialoprotein (BSP) and osteopotin (OPN) after 7 days coculture. In vivo, transplantation of autologous PRF and allogeneic TDM into fresh tooth extraction socket achieved successful root regeneration 3 months postsurgery, characterized by the regeneration of cementum and periodontal ligament (PDL)-like tissues with orientated fibers, indicative of functional restoration. The results suggest that tooth root connected to the alveolar bone by cementum-PDL complex can be regenerated through the implantation of PRF and TDM in a tooth socket microenvironment, probably by homing of BMSCs and PDLSCs. Furthermore, bioactive cues and inductive microenvironment are key factors for endogenous regeneration. This approach provides a tangible pathway toward clinical translation. PMID:25111570

  14. Case presentation of florid cemento-osseous dysplasia with concomitant cemento-ossifying fibroma discovered during implant explantation.

    PubMed

    Gerlach, Robert C; Dixon, Douglas R; Goksel, Tamer; Castle, James T; Henry, Walter A

    2013-03-01

    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

  15. Clinical Performance and Safety of 108 SpineJack Implantations: 1-Year Results of a Prospective Multicentre Single-Arm Registry Study

    PubMed Central

    Noriega, David; Maestretti, Gianluca; Renaud, Christian; Francaviglia, Natale; Ould-Slimane, Mourad; Queinnec, Steffen; Ekkerlein, Helmut; Hassel, Frank; Gumpert, Rainer; Sabatier, Pascal; Huet, Hervé; Plasencia, Miguel; Theumann, Nicolas; Kunsky, Alexander; Krüger, Antonio

    2015-01-01

    This prospective, consecutive, multicentre observational registry aimed to confirm the safety and clinical performance of the SpineJack system for the treatment of vertebral compression fractures (VCF) of traumatic origin. We enrolled 103 patients (median age: 61.6 years) with 108 VCF due to trauma, or traumatic VCF with associated osteoporosis. Primary outcome was back pain intensity (VAS). Secondary outcomes were Oswestry Disability Index (ODI), EuroQol-VAS, and analgesic consumption. 48 hours after surgery, a median relative decrease in pain intensity of 81.5% was observed associated with a significant reduction in analgesic intake. Improvements in disability (91.3% decrease in ODI score) and in quality of life (increase 21.1% of EQ-VAS score) were obtained 3 months after surgery. All results were maintained at 12 months. A reduction in the kyphotic angulation was observed postoperatively (−5.4 ± 6.3°; p < 0.001), remained at 12 months (−4.4 ± 6.0°, p = 0.002). No adverse events were implant-related and none required device removal. Three patients (2.9%) experienced procedure-related complications. The overall adjacent fracture rate up to 1 year after surgery was 2.9%. The SpineJack procedure is an effective, low-risk procedure for patients with traumatic VCF allowing a fast and sustained improvement in quality of life over 1 year after surgery. PMID:26844224

  16. Transfemoral Aortic Valve Implantation with the New Edwards Sapien 3 Valve for Treatment of Severe Aortic Stenosis—Impact of Valve Size in a Single Center Experience

    PubMed Central

    Wöhrle, Jochen; Gonska, Birgid; Rodewald, Christoph; Seeger, Julia; Scharnbeck, Dominik; Rottbauer, Wolfgang

    2016-01-01

    Aims The third generation Edwards Sapien 3 (Edwards Lifesciences Inc., Irvine, California) system was optimized to reduce residual aortic regurgitation and vascular complications. Methods and Results 235 patients with severe symptomatic aortic stenosis were prospectively enrolled. Transcatheter aortic valve implantations (TAVI) were performed without general anesthesia by transfemoral approach. Patients were followed for 30 days. Patients received 23mm (N = 77), 26mm (N = 91) or 29mm (N = 67) valve based on pre-procedural 256 multislice computer tomography. Mean oversizing did not differ between the 3 valves. There was no residual moderate or severe aortic regurgitation. Rate of mild aortic regurgitation and regurgitation index did not differ between groups. There was no switch to general anesthesia or conversion to surgery. Rate of major vascular complication was 3.0% with no difference between valve and delivery sheath sizes. Within 30 days rates of all cause mortality (2.6%) and stroke (2.1%) were low. Conclusions In patients with severe aortic stenosis transfemoral TAVI with the Edwards Sapien 3 valve without general anesthesia was associated with a high rate of device success, no moderate or severe residual aortic regurgitation, low rates of major vascular complication, mortality and stroke within 30 days with no difference between the 3 valve sizes. Trial Registration ClinicalTrials.gov NCT02162069 PMID:27003573

  17. On the use of EMI for the assessment of dental implant stability

    NASA Astrophysics Data System (ADS)

    La Malfa Ribolla, Emma; Rizzo, Piervincenzo; Gulizzi, Vincenzo

    2014-03-01

    The achievement and the maintenance of dental implant stability are prerequisites for the long-term success of the osseointegration process. Since implant stability occurs at different stages, it is clinically required to monitor an implant over time, i.e. between the surgery and the placement of the artificial tooth. In this framework, non-invasive tests able to assess the degree of osseointegration are necessary. In this paper, the electromechanical impedance (EMI) method is proposed to monitor the stability of dental implants. A 3D finite element model of a piezoceramic transducer (PZT) bonded to a dental implant placed into the bone was created, considering the presence of a bone-implant interface subjected to Young's modulus change. The numerical model was validated experimentally by testing bovine bone samples. The EMI response of a PZT, bonded to the abutment screwed to implants inserted to the bone, was measured. To simulate the osseointegration process a pulp canal sealer was used to secure the implant to the bone. It was found that the PZT's admittance is sensitive to the stiffness variation of the bone-implant interface. The results show that EMIbased method is able (i) to evaluate the material properties around the implant, and (ii) to promote a novel non-invasive monitoring of dental implant surgical procedure.

  18. [Comperative study of implant surface characteristics].

    PubMed

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

    2013-12-01

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

  19. Inadvertent tooth movement with fixed lingual retainers.

    PubMed

    Shaughnessy, Timothy G; Proffit, William R; Samara, Said A

    2016-02-01

    Fixed retainers are effective in maintaining the alignment of the anterior teeth more than 90% of the time, but they can produce inadvertent tooth movement that in the most severe instances requires orthodontic retreatment managed with a periodontist. This is different from relapse into crowding when a fixed retainer is lost. These problems arise when the retainer breaks but remains bonded to some or all teeth, or when an intact retainer is distorted by function or was not passive when bonded. In both instances, torque of the affected teeth is the predominant outcome. A fixed retainer made with dead soft wire is the least likely to create torque problems but is the most likely to break. Highly flexible twist wires bonded to all the teeth appear to be the most likely to produce inadvertent tooth movement, but this also can occur with stiffer wires bonded only to the canines. Orthodontists, general dentists, and patients should be aware of possible problems with fixed retainers, especially those with all teeth bonded, because the patient might not notice partial debonding. Regular observations of patients wearing fixed retainers by orthodontists in the short term and family dentists in the long term are needed. PMID:26827985

  20. Sensory and motor function of teeth and dental implants: a basis for osseoperception.

    PubMed

    Trulsson, Mats

    2005-01-01

    1. When dental implants are loaded mechanically, a sensation, often referred to as osseoperception, is evoked. The sensory signals underlying this phenomenon are qualitatively different from the signals evoked when loading a natural tooth. In contrast with osseointegrated dental implants, natural teeth are equipped with periodontal mechanoreceptors that signal information about tooth loads. In the present review, the functional properties of human periodontal mechanoreceptors will be presented, along with a discussion about their likely functional role in the control of human jaw actions. 2. Microneurographic experiments reveal that human periodontal mechanoreceptors adapt slowly to maintained tooth loads. Populations of periodontal receptors encode information about both which teeth are loaded and the direction of forces applied to individual teeth. 3. Most receptors exhibit a markedly curved relationship between discharge rate and force amplitude, featuring the highest sensitivity to changes in tooth load at surprisingly low forces (below 1 N for anterior teeth and 4 N for posterior teeth). Accordingly, periodontal receptors efficiently encode tooth load when subjects first contact, hold and gently manipulate food by the teeth. In contrast, only a minority of receptors encodes the rapid and strong increase in force generated when biting through food. 4. It is concluded that humans use periodontal afferent signals to control jaw actions associated with intra-oral manipulation of food rather than exertion of jaw power actions. Consequently, patients who lack information from periodontal receptors show an impaired fine motor control of the mandible. PMID:15730446