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Sample records for single tooth implant

  1. A prospective study of Astra single tooth implants.

    PubMed

    Palmer, R M; Smith, B J; Palmer, P J; Floyd, P D

    1997-06-01

    A new design of single tooth implant (AstraTech, Molndal Sweden) featuring a microthreaded conical neck and TiO blast surface was evaluated clinically and radiographically after 2 years in function. Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had 4, 13 mm and 11, 15 mm implants placed under local anaesthesia and left for a period of 6 months before exposure and abutment connection/crown fabrication. All patients were seen at 4 to 6 monthly intervals for hygienist maintenance. Radiographs using Rinn holders and a long cone technique were taken at the crown insertion and after 1 year (14 subjects) and 2 years (12 subjects). All implants were successfully integrated at stage 2, and no implants have been lost. The internal conical seal design of the abutment/implant interface facilitated connection and there were no cases of abutment screw loosening. No soft tissue problems were observed, and the gingival morphology/health was well maintained. One crown was recemented after 18 months in function, and 1 crown was replaced because of a fracture to the porcelain incisal edge. At crown insertion, the mean bone level was 0.46 to 0.48 mm apical to the top of the implant and there were no statistically significant changes in the bone level over the 2 years of the study. In conclusion, the single tooth Astra implants were highly successful and bone changes within the first 2 years of function were comparable with other systems reporting high long-term success rates. PMID:9586461

  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. 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

  5. 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; Koçer, Gülperi; Kaya, Bulem Üreyen

    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

  6. 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

  7. 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

  8. 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

    Peñarrocha-Diago, Miguel; Pradíes, Guillermo; Sola-Ruiz, María-Fernanda; Agustín-Panadero, Rubén

    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

  9. Implant-connected versus tooth-connected implant-supported partial dentures: 2-year clinical and radiographic comparative evaluation.

    PubMed

    Mostafa, Tamer Mohamed; El-Sheikh, Mohamed M; Abd El-Fattah, Fadel

    2015-01-01

    The purpose of this study was to clinically and radiographically compare implant-connected and tooth-connected implant-supported fixed-detachable mandibular partial dentures. Twenty partially edentulous patients (age range: 25 to 50 years) with mandibular Kennedy Class II configurations were equally divided into two groups receiving a three-unit, fixed-detachable, screw-retained partial denture. Group 1 comprised patients with unilateral missing mandibular molars and premolars. Two implants were placed at the mandibular first premolar and first molar areas. Group 2 comprised patients with missing mandibular molars and second premolars. An implant was placed at the mandibular first molar area, the first premolar was prepared, and a coping was cemented to the tooth with permanent cement. Each case was evaluated clinically and radiographically at baseline (partial denture insertion) and after 6, 12, and 24 months. Data were collected and statistically analyzed using repeated-measures one-way and two-way analysis of variance tests. There was no statistically significant difference between the two groups (P > .05). The implant-tooth-supported prosthesis provided an equally predictable treatment option compared to the totally implant-supported prosthesis in terms of implant survival and loss of marginal bone. PMID:25909533

  10. 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

  11. Implant Site Development by Horizontal Tooth Movement to an Esthetic Area: A Case Report.

    PubMed

    Wada, Yoshiyuki; Yoshimura, Harunori; Mikami, Itaru; Matsuzawa, Kousuke; Mizuno, Morimichi

    2015-01-01

    This case report describes the treatment of a woman who lost a central incisor. The socket developed severe tissue defects. She rejected hard and soft tissue management and the use of biomaterials. The lateral incisor was moved mesially with orthodontic treatment. The tissue defects were filled with the alveolar bone of the moved tooth and adequate bone volume was generated behind it. An implant was placed in the space that was generated without any tissue augmentation. The moved tooth had sound periodontal tissue and was restored without preparation. The horizontal tooth movement enabled an esthetic outcome with minimal intervention. PMID:26357699

  12. 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

  13. 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

  14. Dynamic UCLA for single tilted implant in an aesthetic region

    PubMed Central

    Goiato, Marcelo Coelho; Sônego, Mariana Vilela; da Silva, Emily Vivianne Freitas; de Carvalho Dekon, Stefan Fiuza; de Medeiros, Rodrigo Antonio; Carvalho, Karina Helga Turcio de; dos Santos, Daniela Micheline

    2015-01-01

    Introduction The aim of this paper was to present a rehabilitation of a patient with a dynamic universal castable long abutment (UCLA) for a single tilted implant in the anterior maxillary area. Presentation of case A 57-year-old male patient attended the dentistry college clinic complaining of a vertical fracture of a residual root of the dental element 22. The tooth extraction was indicated for the implant installation. Due to the socket buccal wall thickness, the implant was installed with an inclination to the palate. It was done in a two-stage surgical protocol, and an external hexagon implant (3.75 × 11.5 mm) was placed. After a six-month healing period to correct the implant position, a dynamic UCLA was set in place, rectifying the implant emergence profile at 20°. The ceramic structure fitting was performed and, after the patient’s consent, the prosthesis was finalized and installed. Discussion After a follow-up period of twenty months, no complications were observed. Conclusion The installation of tilted implants with a dynamic UCLA may be a viable option, faster and less invasive than bone grafts. PMID:25618842

  15. 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

  16. 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

  17. Clinical evaluation of implant survival based on size and site of placement: A retrospective study of immediate implants at single rooted teeth sites

    PubMed Central

    Ramalingam, Sundar; Al-Hindi, Maryam; Al-Eid, Raniah Abdullah; Nooh, Nasser

    2015-01-01

    Objectives This retrospective clinical study sought to evaluate the survival of immediate implants placed at maxillary and mandibular single-rooted tooth extraction sites and to determine the relationship among implant size, placement site, and implant survival. Methods Between January 2010 and June 2011, 85 patients (33 males, 52 females; mean age: 45 years) underwent immediate implant placement after extraction of single-rooted teeth. All implants were restored between 12 and 14 weeks after implant placement. The implant survival and its relationship with implant size and implantation site were evaluated by odds ratios (ORs). Results Implants were placed at the following sites: upper central incisor (UCI, n = 35), upper lateral incisor (ULI, n = 27), upper second premolar (U2ndP, n = 36), lower incisor (LI, n = 53), and lower premolar (LP, n = 22). Implants of the following sizes were used: 5 × 10 mm (n = 24), 5 × 8 mm (n = 21), 4.3 × 10 mm (n = 77), 4.3 × 8 mm (n = 36), 3.5 × 10 mm (n = 12), and 3.5 × 8 mm (n = 3). After a mean follow-up time of 47 months, the overall implant survival rate was 96%. Survival rate was highest at the LI site (98.1%) and lowest at the ULI site (92.6%). All of the 5-mm implants survived (100%), as did most of the 4.3 × 10 mm implants (96.1%). Implants of 4.3 × 8 mm and 3.5 × 10 mm were the least successful (91.7%). Mandibular implants had a better survival rate (97.3%) than maxillary implants (94.9%). There was no significant OR of increased survival for any particular implant size or site. Conclusions Immediate implant placement in fresh extraction sockets can give predictable clinical outcomes, regardless of the implant size and site of placement. PMID:26082578

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  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. Cochlear Implantation and Single Sided Deafness

    PubMed Central

    Tokita, Joshua; Dunn, Camille; Hansen, Marlan R.

    2014-01-01

    Purpose of review Recently, more patients with single-sided deafness (SSD) have been undergoing cochlear implantation. We review recent studies and case reports to provide an overview of the efficacy of cochlear implants (CIs) to rehabilitate patients with SSD with regards to sound localization, speech discrimination, and tinnitus suppression. Recent findings There are a growing number of studies evaluating the effect of cochlear implantation for rehabilitation of the deficits associated with SSD over the past several years as more centers offer this treatment modality to patients with SSD. While individual studies have few subjects and are underpowered, the vast majority report improvement in sound localization, speech understanding in quiet and noise, and tinnitus. In some cases the outcomes with CI appear superior to those achieved with other devices including contralateral routing of sound (CROS) devices and osseointegrated implants (OIs). Summary Although CI is not an FDA-approved treatment for SSD, several recent studies show improvements in speech understanding, sound localization, and tinnitus. Due to the low number of cases, it is difficult to conclusively compare outcomes achieved with CIs and those provided by other devices. However, based on encouraging early results and the unique ability to restore binaural sound processing, a growing number of centers offer CIs as treatment for SSD. Forthcoming studies will help define outcome expectations in different populations. PMID:25050566

  2. Hinged Single Piece Putty Index for Preclinical Demonstration of Tooth Preparation for Fixed Partial Dentures and Crowns

    PubMed Central

    Kumar, Shallabh

    2015-01-01

    Introduction: Different types of indices are being used for assessment of tooth preparation. All these indices are used to visualize tooth preparations in a particular plane. A single versatile index which could help to visualize tooth preparations in different planes is non-existent. The need for fabrication of such an index and its reliability is of utmost important to provide quality tooth preparations. Purpose: The purpose of the study is to fabricate a hinged single piece sectioned index which could be used to visualize tooth preparation in different planes and check its reliability in-vitro on phantom models. Materials and Methods: Ten preclinical students were selected in random for preparing three teeth each. The three teeth preparations are classified as Group A, Group B and Group C based on the non-usage of index, usage of sectioned index and hinged single piece sectioned index respectively. Students were made to do provisional restorations after the tooth preparations. Then a questionnaire was given to students to score the duration/accuracy/comfort during tooth preparation and duration/accuracy of provisional restorations for each of the Groups A,B and C. Results: In Group C, 90% of students found the final preparation to be very accurate. The time taken for fabrication of provisional restoration using sectioned hinged index by 60% of Group C students was 20 to 30 min. Conclusion: This hinged index is a viable option when accuracy of tooth preparation and speedy fabrication of provisional restoration is required. PMID:26023634

  3. 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.

  4. 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

  5. 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 ...

  6. Single ion implantation for solid state quantum computer development

    SciTech Connect

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

    2001-12-18

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

  7. 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

  8. Adults with one cochlear implant for single-sided deafness are

    E-print Network

    Litovsky, Ruth

    Adults with one cochlear implant for single-sided deafness are invited to take part in our research studies. Criteria: Cochlear Implant in one ear Normal or near-normal hearing in the non-implanted ear before testing begins and stay in a comfortable nearby hotel. Do you wear a cochlear implant for single

  9. 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.

  10. [The single missing tooth. Treatment possibilities from an orthodontic view point].

    PubMed

    Kiekens, R M; Kuijpers-Jagtman, A M

    1999-05-01

    In patients with single missing teeth, a standard treatment plan does not exist. The treatment plan depends on the age and the facial profile, the malocclusion, the interdigitation, the available space, the amount of bone, the shape, color, and the level of the gingiva of the neighbouring teeth. Closing or opening the diastema should be considered. A diagnostic set-up of the final occlusion can provide more insight into the final result that can be expected from the treatment modalities. Orthodontic closure of the diastema is preferable, but not always feasible or desirable and compensatory extractions may be necessary. In children, auto-transplantation is an option. In adults with a sufficient amount of bone the placement of an implant may be the treatment of choice. Frequently, preimplantological bone augmentation is necessary because otherwise prosthodontic replacement is the only solution. PMID:11930361

  11. Chromium single photon emitters in diamond fabricated by ion implantation

    E-print Network

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

    2010-01-25

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

  12. Investigating Long-Term Effects of Cochlear Implantation in Single-Sided Deafness: A Best Practice

    E-print Network

    Litovsky, Ruth

    Investigating Long-Term Effects of Cochlear Implantation in Single-Sided Deafness: A Best Practice long-term benefits of cochlear implantation in a patient with single-sided deafness (SSD) with respect underwent right-sided cochlear implantation. Methods: The subject was evaluated at 6, 9, 12, and 18 months

  13. Coexistence of two talon cusps and two dens invaginatus in a single tooth with associated radicular cyst-a case report and review of literature

    PubMed Central

    Singh, Mukund; Saluja, Harish; Ladda, Ruchi

    2014-01-01

    Talon cusp (TC) and dens invaginatus (DI) are relatively rare developmental anomalies which affect the shape of teeth. TC is an additional cusp that projects predominately from the lingual surface of anterior teeth. DI is a deep surface invagination of the crown or root which is commonly detected on routine radiographic examination. Both of these anomalies are observed more frequently in permanent maxillary lateral incisor. Isolated cases of single TC and DI are extensively reported in dental literature. Occasionally two talon cusps (TCs) in the same tooth as well as double and triple invaginations in one tooth are reported separately. Coexistence of these two anomalies in a single tooth is considered extremely rare, but still there are few reported cases. However, coexistence of two TCs and double DI in a single tooth is not reported till date. We hereby report the first case of coexistence of two TCs and double DI in a single tooth of a 23 year old female and use of platelet-rich fibrin (PRF) in the management of associated radicular cyst. Also, literature on coexistence of these two anomalies in a single tooth is reviewed. Key words:Coexistence, dens invaginatus, radicular cyst, talon cusp. PMID:25593669

  14. 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.

  15. Preventive implantations.

    PubMed

    Denissen, H W; Kalk, W

    1991-02-01

    Preventive implantology is concerned with the preservation of the alveolar ridge of the (edentulous) jaw. Maintaining the volume of the alveolar ridge is a major problem in the prevention of oral disease. Loss of teeth and tooth roots leads to resorption of residual ridges. This being so, it is a logical approach to substitute artificial analogues for lost tooth roots. Hydroxyapatite implants have been studied as submerged tooth root substitutes and shown to maintain the bulk of the alveolar ridge. A drawback of the implants is that the ridge maintenance depends solely on the physical presence of the hydroxyapatite implants. No physiological influence on bone preservation can be attributed to the implants. However, long term research indicates that 75 per cent of the implants survive under full lower dentures and 100 per cent of the implants under fixed partial dentures. PMID:1848531

  16. 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.

  17. Tooth Problems

    MedlinePLUS

    ... or is the tooth loose in its socket? Yes Your pain may be from a FRACTURED, CRACKED or LOOSE TOOTH. Save any pieces of the tooth, wrap them in a cool, moist cloth and see your dentist as soon as possible. No 4. ... when you eat cold foods or liquids? Yes Your pain may be from a CAVITY. Make ...

  18. Restoring the single lower incisor implant with esthetics, antirotation, and retrievability.

    PubMed

    Marlin, G M; Baraban, D

    1994-05-01

    The long-term success of restoring the lower incisor implant is partially dependent on retrievability of all components down to the implant. Because this implant is usually placed vertically or buccally in the bone, the ability to achieve esthetics without seeing the screw access hole becomes critical. The emergence profile of the crown overlying the implant fixture ultimately dictates the esthetics. The single crown can also become loose during function and, therefore, antirotation of the abutment is imperative. The Octa-Hex Implant Restoration System presents an alternative method of achieving gingival seal with a titanium-alloy connector to the implant, emergence profile with a custom-fabricated casting on this connector, antirotation from intimate contact with implant indexing, and retrievability by a fixation screw and cementation. With the lower incisor, this system offers retrievability without the screw access hole affecting esthetics. PMID:8055527

  19. 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

  20. Single-Unit Stability Using Chronically Implanted Multielectrode Arrays

    PubMed Central

    Dickey, Adam S.; Suminski, Aaron; Amit, Yali; Hatsopoulos, Nicholas G.

    2009-01-01

    The use of chronic intracortical multielectrode arrays has become increasingly prevalent in neurophysiological experiments. However, it is not obvious whether neuronal signals obtained over multiple recording sessions come from the same or different neurons. Here, we develop a criterion to assess single-unit stability by measuring the similarity of 1) average spike waveforms and 2) interspike interval histograms (ISIHs). Neuronal activity was recorded from four Utah arrays implanted in primary motor and premotor cortices in three rhesus macaque monkeys during 10 recording sessions over a 15- to 17-day period. A unit was defined as stable through a given day if the stability criterion was satisfied on all recordings leading up to that day. We found that 57% of the original units were stable through 7 days, 43% were stable through 10 days, and 39% were stable through 15 days. Moreover, stable units were more likely to remain stable in subsequent recording sessions (i.e., 89% of the neurons that were stable through four sessions remained stable on the fifth). Using both waveform and ISIH data instead of just waveforms improved performance by reducing the number of false positives. We also demonstrate that this method can be used to track neurons across days, even during adaptation to a visuomotor rotation. Identifying a stable subset of neurons should allow the study of long-term learning effects across days and has practical implications for pooling of behavioral data across days and for increasing the effectiveness of brain–machine interfaces. PMID:19535480

  1. 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

  2. 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

  3. 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 1-11 ms 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

  4. 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%.

  5. 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.

  6. Thermal behaviour of helium-implanted spinel single crystals

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  7. 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

  8. Impacted tooth

    MedlinePLUS

    ... emerged tooth can trap food, plaque, and other debris in the soft tissue around it, which can ... mouth odor. This is called pericoronitis. The retained debris may also lead to the decay on the ...

  9. 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 ...

  10. 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…

  11. The local structure and ferromagnetism in Fe-implanted SrTiO? 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 Fe? 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 2×10¹? Fe atom/cm², which could be correlated with the metallic Fe? 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).

  12. 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

  13. 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 ...

  14. 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 onés 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

  15. 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 onés 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

  16. 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).

  17. Osseointegrated implants--principles and practice: 2. Prosthetic rehabilitation with osseointegrated implants.

    PubMed

    Watson, R M; Davis, D M; Coward, T

    1989-11-01

    In this series of three articles the authors describe some of the principles and practice of osseointegrated implants. Part 1 gave a detailed description of the surgical techniques required to establish osseointegrated implant fixtures (with special reference to the Branemark system), and gave guidance on patient selection and treatment planning. Part 2 now considers prosthetic rehabilitation techniques with osseointegrated implants for complete dentures, complete overdentures, partial bridges, and single tooth replacement cases. Part 3 will conclude the series by presenting a number of case studies. PMID:2700969

  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. Effect of H + ion implantation on structural, morphological, optical and dielectric properties of L-arginine monohydrochloride monohydrate single crystals

    NASA Astrophysics Data System (ADS)

    Sangeetha, K.; Babu, R. Ramesh; Kumar, P.; Bhagvannarayana, G.; Ramamurthi, K.

    2011-06-01

    L-arginine monohydrochloride monohydrate (LAHCl) single crystals have been implanted with 100 keV H + ions at different ion fluence ranging from 10 12 to 10 15 ions/cm 2. Implanted LAHCl single crystals have been investigated for property changes. Crystal surface and crystalline perfection of the pristine and implanted crystals were analyzed by atomic force microscope and high-resolution X-ray diffraction studies, respectively. Optical absorption bands induced by colour centers, refractive index and birefringence, mechanical stability and dielectric constant of implanted crystals were studied at different ion fluence and compared with that of pristine LAHCl single crystal.

  20. Cross-sectional transmission electron microscopy method and studies of implant damage in single crystal diamond

    SciTech Connect

    Hickey, D.P.; Kuryliw, E.; Siebein, K.; Jones, K.S.; Chodelka, R.; Elliman, R.

    2006-07-15

    Few transmission electron microscopy (TEM) studies of single crystal diamond have been reported, most likely due to the time and difficulty involved in sample preparation. A method is described for creating a TEM cross section of single crystal diamond using a focused ion beam and in situ lift-out. The method results in samples approximately 10 {mu}m long by 3 {mu}m deep with an average thickness of 100-300 nm. The total time to prepare a cross-sectional TEM sample of diamond is less than 5 h. The method also allows for additional thinning to facilitate high resolution TEM imaging, and can be applied to oddly shaped diamond samples. This sample preparation technique has been applied to the study of ion implantation damage in single crystal diamond and its evolution upon annealing. High-pressure-high-temperature diamonds were implanted with Si{sup +} at an energy of 1 MeV and a temperature of 30 deg. C. One sample, with a (110) surface, was implanted with a dose of 1x10{sup 14} Si cm{sup -2} and annealed at 950 deg. C for 10 and 40 min. No significant defect formation or evolution was discernible by cross-sectional transmission electron microscopy. Another sample, with a (100) orientation, was implanted with 1 MeV at 1x10{sup 15} Si cm{sup -2} and annealed at 1050 deg. C for 10 min. Prior to annealing, a heavily damaged but still crystalline region was observed. Upon annealing, the sample showed no signs of conversion either to an amorphous form of carbon or to graphite. This is unexpected as the energy and dose are above the previously reported graphitization threshold for diamond. Higher annealing temperatures and possibly a high vacuum will be required for future study of defect formation, evolution, and phase transformations in ion-implanted single crystal diamond.

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

    NASA Astrophysics Data System (ADS)

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

    2003-06-01

    In the near future, devices that employ single atoms to store or manipulate information will be constructed. For example, a solid-state quantum computer has been proposed that encodes information in the nuclear spin of shallow arrays of single 31P atoms (quantum bits or qubits) in a matrix of pure silicon. Construction of these devices presents formidable challenges. One strategy is to use single ion implantation, with the energy range of 10 to 20 keV, to load the qubits into prefabricated cells of the device with a period of a few tens of nanometres. We have developed a method of single ion implantation that employs detector electrodes adjacent to the prefabricated qubit cells that can detect on-line single keV ion strikes appropriate for the fabrication of shallow arrays. Our method of the sub-20 keV single ion detection utilizes a pure silicon substrate with a very high resistivity, a thin (5 nm) SiO2 surface layer, biased electrodes applied to the surface and sensitive electronics that can detect the charge transient from single keV ion strikes. We show that our detectors have a near 100% efficiency for keV ions, extremely thin dead layer thickness (˜5 nm) and a wide sensitive region extending laterally from the electrodes (greater than 15 ?m) where the nanometre cells can be constructed. We compare the method with the other methods, such as those of measuring the secondary electrons or phonons induced by single ion impacts.

  2. 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

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

    PubMed Central

    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 Ménière's disease and profound sensorineural hearing loss. Study Design. Prospective study. Method. Five patients with single-sided Ménière'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 Ménière'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. Dental Caries (Tooth Decay)

    MedlinePLUS

    ... Find Data by Topic > Dental Caries (Tooth Decay) Dental Caries (Tooth Decay) Main Content Dental caries (tooth decay) remains the most prevalent chronic ... important source of information on oral health and dental care in the United States since the early ...

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

    PubMed

    Saatci, Ali Osman; Ayhan, Ziya; Take?, Ömer; Yaman, Aylin; Bajin, F Meltem Söylev

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

    PubMed Central

    Saatci, Ali Osman; Ayhan, Ziya; Take?, Ömer; Yaman, Aylin; Bajin, F. Meltem Söylev

    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

  7. Magnetic and electrical characterization of TiO2 single crystals co-implanted with iron and cobalt

    NASA Astrophysics Data System (ADS)

    Silva, C.; Costa, A. R. G.; da Silva, R. C.; Alves, L. C.; Ferreira, L. P.; Carvalho, M. D.; Franco, N.; Godinho, M.; Cruz, M. M.

    2014-09-01

    Single-crystals of TiO2 rutile were co-implanted with iron and cobalt to investigate the combined role of these ions in the magnetic properties of the system. The implantations were carried out using an energy of 150 keV and different fluences to investigate their influence in the magnetic and electrical properties of the implanted samples. For the higher fluences the as implanted single crystals exhibit superparamagnetic behaviour associated with the formation of nanosized magnetic aggregates. Annealing treatments were performed at 673 K and 1073 K, inducing recovery of the lattice structure and the evolution of the formed phases. Iron and cobalt play different roles in the implanted region, the presence of iron inhibiting the formation of cobalt aggregates during annealing at 1073 K.

  8. RECONSTRUCTION OF 3D TOOTH IMAGES S. Buchaillard1

    E-print Network

    Payan, Yohan

    the shape of a tooth using only 3D crown information and without the use of X-rays, CT or MRI. Various, and treatment simulations. For example, a dental implant can be inserted into the jawbone when a tooth tomography (CT) is the most efficient way of generating 3D objects. However, CT imag- ing of dental patients

  9. 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, Mölndal, 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

  10. 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

  11. 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.

  12. 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.

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

    PubMed

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

    2012-12-01

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

  14. Study of the negative magneto-resistance of single proton-implanted lithium-doped ZnO microwires

    NASA Astrophysics Data System (ADS)

    Lorite, I.; Zandalazini, C.; Esquinazi, P.; Spemann, D.; Friedländer, S.; Pöppl, A.; Michalsky, T.; Grundmann, M.; Vogt, J.; Meijer, J.; Heluani, S. P.; Ohldag, H.; Adeagbo, W. A.; Nayak, S. K.; Hergert, W.; Ernst, A.; Hoffmann, M.

    2015-06-01

    The magneto-transport properties of single proton-implanted ZnO and of Li(7%)-doped ZnO microwires have been studied. The as-grown microwires were highly insulating and not magnetic. After proton implantation the Li(7%) doped ZnO microwires showed a non-monotonous behavior of the negative magneto-resistance (MR) at temperature above 150 K. This is in contrast to the monotonous NMR observed below 50 K for proton-implanted ZnO. The observed difference in the transport properties of the wires is related to the amount of stable Zn vacancies created at the near surface region by the proton implantation and Li doping. The magnetic field dependence of the resistance might be explained by the formation of a magnetic/non-magnetic heterostructure in the wire after proton implantation.

  15. The central single implant in the edentulous mandible: improvement of function and quality of life. A report of 2 cases.

    PubMed

    Wolfart, Stefan; Braasch, Katja; Brunzel, Simone; Kern, Matthias

    2008-01-01

    Implant-retained overdentures are a reliable treatment option for edentulous patients, especially when only few implants can be placed. Internationally, 2 implants are considered adequate to retain an overdenture in the edentulous mandible. However, for many patients, 2 implants can be cost-prohibitive. By means of 2 clinical cases, it is shown that the insertion of a single implant in the middle of the mandible might stabilize the prosthesis and improve the oral health quality of life and the chewing function. A ball attachment with a screw-activated matrix was used to retain the overdenture. Early clinical results are promising. However, before this method can be recommended for general clinical application, long- term clinical results are needed. PMID:19107261

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

    PubMed

    Pleyer, Uwe; Klamann, Matthias; Laurent, Thierry-Jens; Mänz, 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 µg). 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

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

    PubMed Central

    Jiménez-Melendo, Manuel; Llena-Blasco, Oriol; Bruguera, August; Llena-Blasco, Jaime; Yáñez-Vico, Rosa-María; García-Calderón, Manuel; Vaquero-Aguilar, Cristina; Velázquez-Cayón, Rocío; Gutiérrez-Pérez, José-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

  18. 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

  19. 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.

  20. Rutherford backscattering and nuclear reaction analyses of hydrogen ion-implanted ZnO bulk single crystals

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    The origins of low resistivity in H ion-implanted ZnO bulk single crystals are studied by Rutherford backscattering spectrometry (RBS), nuclear reaction analysis (NRA) photoluminescence (PL), and Van der Pauw methods. The H-ion implantation (peak concentration: 1.45 × 1020 cm-3) into ZnO is performed using a 500 keV implanter. The resistivity decreases from 2.5 × 103 ? cm for unimplanted ZnO to 6.5 ? cm for as-implanted one. RBS measurements show that Zn interstitial as a shallow donor is not recognized in as-implanted samples. From photoluminescence measurements, the broad green band emission is observed in as-implanted samples. NRA measurements for as-implanted ZnO suggest the existence of the oxygen interstitial. The origins of the low resistivity in the as-implanted sample are attributed to both the H interstitial as a shallow donor and complex donor between H and disordered O. The activation energy of H related donors estimated from the temperature dependence of carrier concentration is 29 meV.

  1. Comparison of Maxillary Molar Distalization with an Implant-Supported Distal Jet and a Traditional Tooth-Supported Distal Jet Appliance

    PubMed Central

    Cozzani, Mauro; Pasini, Marco; Zallio, Francesco; Ritucci, Robert; Mutinelli, Sabrina; Mazzotta, Laura; Giuca, Maria Rita; Piras, Vincenzo

    2014-01-01

    Aim. To investigate and compare the efficiency of two appliances for molar distalization: the bone-anchored distal screw (DS) and the traditional tooth-supported distal jet (DJ) for molar distalization and anchorage loss. Methods. Tests (18 subjects) were treated with a DS and controls (18 subjects) were treated with a DJ. Lateral cephalograms were obtained before and at the end of molar distalization and were analysed. Shapiro Wilk test, unpaired t-test, and Wilcoxon rank-sum test were applied according to values distribution. The ? level was fixed at 0.05. Results. Maxillary first molars were successfully distalized into a Class I relationship in all patients. The mean molar distalization and treatment time were similar in both groups. The DS group exhibited a spontaneous distalization (2.1 ± 0.9?mm) of the first premolar with control of anchorage loss, distal tipping, extrusion, and skeletal changes. Conclusions. The DS is an adequate compliance-free distalizing appliance that can be used safely for the correction of Class II malocclusions. In comparison to the traditional DJ, the DS enables not only a good rate of molar distalization, but also a spontaneous distalization of the first premolars. PMID:25018770

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

    PubMed

    Burke, Peter; Rutherglen, Christopher

    2010-08-01

    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

  3. Single ion implantation with scanning probe alignment A. Persaud, F. I. Allen, F. Gicquel, S. J. Park, J. A. Liddle, and T. Schenkela)

    E-print Network

    Single ion implantation with scanning probe alignment A. Persaud, F. I. Allen, F. Gicquel, S. J December 2004) We present results from our development of a single ion implantation technique integrated single ion placement. We address this through integration of the ion beam with a scanning probe tip

  4. 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; Araújo, 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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    As the intrinsic origin of the high-temperature ferromagnetism often observed in wide-gap dilute magnetic semiconductors becomes increasingly debated, there is a growing need for comprehensive studies on the single-phase region of the phase diagram of these materials. Here we report on the magnetic and structural properties of Fe-doped ZnO prepared by ion implantation of ZnO single crystals. A detailed structural characterization shows that the Fe impurities substitute for Zn in ZnO in a wurtzite Zn1-xFexO phase which is coherent with the ZnO host. In addition, the density of beam-induced defects is progressively decreased by thermal annealing up to 900?° C, from highly disordered after implantation to highly crystalline upon subsequent annealing. Based on a detailed analysis of the magnetometry data, we demonstrate that isolated Fe impurities occupying Zn-substitutional sites behave as localized paramagnetic moments down to 2 K, irrespective of the Fe concentration and the density of beam-induced defects. With increasing local concentration of Zn-substitutional Fe, strong nearest-cation-neighbor antiferromagnetic interactions favor the antiparallel alignment of the Fe moments.

  6. 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 ...

  7. Tooth - abnormal colors

    MedlinePLUS

    ... appear as spots or lines in the tooth enamel. Your genes affect your tooth color. Other things ... Infections Inherited diseases may affect the thickness of enamel or the calcium or protein content of the ...

  8. Tooth decay - early childhood

    MedlinePLUS

    Bottle mouth; Bottle carries; Baby bottle tooth decay; Early childhood caries (ECC) ... your baby. It keeps the inside of your baby's mouth healthy and prevents tooth decay. If you are bottle-feeding your baby: ...

  9. Tooth decay - early childhood

    MedlinePLUS

    Bottle mouth; Bottle carries; Baby bottle tooth decay; Early childhood caries (ECC) ... milk by itself is the healthiest food for babies’ teeth. It tends ... the rate of tooth decay can be faster than with sugar alone. ...

  10. Perspective Molecular Tooth Decay

    E-print Network

    DeSalle, Rob

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

  11. 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 100 Hz, 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

  12. 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; Peñarrocha-Oltra, David; Bagán, 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

  13. 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.

  14. 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

  15. 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, José Fábio Guastelli; Pimentel, Angélica Castro; Gomes, Maria Helena; Sendyk, Wilson Roberto; Laganá, 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

  16. Resin-bonded restorations: a strategy for managing anterior tooth loss in adolescence.

    PubMed

    Zitzmann, Nicola U; Özcan, Mutlu; Scherrer, Susanne S; Bühler, Julia M; Weiger, Roland; Krastl, Gabriel

    2015-04-01

    In children or adolescents with anterior tooth loss, space closure with the patient's own teeth should be considered as the first choice to avoid lifelong restorative needs. Thorough diagnostics and treatment planning are required when autotransplantation or orthodontic space closure is considered. If these options are not indicated and a single tooth implant restoration is considered, implant placement should be postponed until adulthood, particularly in young women and in patients with hyperdivergent skeletal growth pattern. A ceramic resin-bonded fixed dental prosthesis with 1 retainer is an excellent treatment solution for the interim period; it may also serve as a long-term restoration, providing that sound enamel structure is present, sufficient framework dimensions have been provided, adhesive cementation techniques have been meticulously applied, and functional contacts of the cantilever pontic avoided. In contrast, a resin-bonded fixed dental prosthesis with a metal framework and retentive preparation is indicated if the palatal enamel structure is compromised, interocclusal clearance is limited, splinting (such as after orthodontic treatment) is required, or more than 1 tooth has to be replaced. PMID:25702966

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

    PubMed

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

    2015-06-01

    We report on the use of helium ion implantation to independently control the out-of-plane lattice constant in epitaxial La0.7Sr0.3MnO3 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 1 0 0 °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.

  19. 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

  20. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    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.

  2. 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.

  3. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-09-01

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

  5. 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

  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. 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

  8. 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.

  9. 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

  10. Nuclear reaction analysis of Ge ion-implanted ZnO bulk single crystals: The evaluation of the displacement in oxygen lattices

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    The displacement of oxygen lattices in Ge ion-implanted ZnO bulk single crystals is studied by nuclear reaction analysis (NAR), photoluminescence (PL), and Van der Pauw methods. The Ge ion-implantation (net concentration: 2.6 × 1020 cm-3) into ZnO is performed using a multiple-step energy. The high resistivity of ?103 ? cm in un-implanted samples remarkably decreased to ?10-2 ? cm after implanting Ge-ion and annealing subsequently. NRA measurements of as-implanted and annealed samples suggest the existence of the lattice displacement of O atoms acting as acceptor defects. As O related defects still remain after annealing, these defects are not attributed to the origin of the low resistivity in 800 and 1000 °C annealed ZnO.

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

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

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

  12. Immediate versus conventional loaded single implants in the posterior mandible: a meta-analysis of randomized controlled trials.

    PubMed

    Moraschini, V; Porto Barboza, E

    2016-01-01

    The purpose of this meta-analysis was to compare implant survival, marginal bone loss, and complications between immediate and conventional loading of single implants installed in the posterior mandible. An extensive electronic search was performed of PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials to identify relevant articles published up to January 2015. After the selection process, five studies met the eligibility criteria and were included. The results of the meta-analysis were expressed in terms of the odds ratio (OR) or standardized mean difference (SMD), with a confidence interval (CI) of 95%. Results were pooled according to heterogeneity using the fixed- or random-effects model. There was no statistically significant difference between the two techniques (immediate loading vs. conventional loading) with regard to implant survival (OR 1.71, 95% CI 0.40 to 7.36; P=0.47). There was no statistically significant difference in marginal bone loss (SMD -0.58, 95% CI -1.55 to 0.38; P=0.24). The reported mechanical and biological complications were common to both types of intervention, with the exception of probing depth, which was greater following the immediate loading technique (SMD 0.13, 95% CI -0.19 to 0.44), although this was not statistically significant (P=0.43). PMID:26259980

  13. Single-walled carbon nanotube growth from ion implanted Fe catalyst Yongho Choi

    E-print Network

    Ural, Ant

    the growth of carbon nanotubes. Typically, transition metal nanoparticles, such as nickel Ni , iron Fe. They systematically characterize the effect of ion implantation dose and energy on the catalyst nanoparticles a liquid solution containing iron nanoparticles.2 More recently, solid thin film layers deposited

  14. Measuring the impedance of the active electrode of a single channel cochlear implant in situ.

    PubMed

    Hrubý, J; Klier, E; Picka, J; Sedlák, S; Betka, J; Valvoda, M

    1988-10-01

    A number of failures of extracochlear implants are caused by a bad contact between the active electrode and the tissue. A novel and simple method has been developed to enable the impedance of the active electrode to be measured before completion of surgery. PMID:3236876

  15. 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

  16. 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?

  17. 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.

  18. Tooth formation - delayed or absent

    MedlinePLUS

    ... at which the tooth comes in varies. Most infants get their first tooth between 6 and 9 months, but it may ... in"? What other symptoms are also present? An infant with delayed or absent tooth formation may have other symptoms and signs that ...

  19. 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

  20. 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.

  1. Computation of tooth axes of existent and missing teeth from 3D CT images.

    PubMed

    Wang, Yang; Wu, Lin; Guo, Huayan; Qiu, Tiantian; Huang, Yuanliang; Lin, Bin; Wang, Lisheng

    2015-12-01

    Orientations of tooth axes are important quantitative information used in dental diagnosis and surgery planning. However, their computation is a complex problem, and the existing methods have respective limitations. This paper proposes new methods to compute 3D tooth axes from 3D CT images for existent teeth with single root or multiple roots and to estimate 3D tooth axes from 3D CT images for missing teeth. The tooth axis of a single-root tooth will be determined by segmenting the pulp cavity of the tooth and computing the principal direction of the pulp cavity, and the estimation of tooth axes of the missing teeth is modeled as an interpolation problem of some quaternions along a 3D curve. The proposed methods can either avoid the difficult teeth segmentation problem or improve the limitations of existing methods. Their effectiveness and practicality are demonstrated by experimental results of different 3D CT images from the clinic. PMID:25941910

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

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

    PubMed Central

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

    2011-01-01

    A tooth is a complex biological organ and consists of multiple tissues including the enamel, dentin, cementum and pulp. Tooth loss is the most common organ failure. Can a tooth be regenerated? Can adult stem cells be orchestrated to regenerate tooth structures such as the enamel, dentin, cementum and dental pulp, or even an entire tooth? If not, what are the therapeutically viable sources of stem cells for tooth regeneration? Do stem cells necessarily need to be taken out of the body, and manipulated ex vivo before they are transplanted for tooth regeneration? How can regenerated teeth be economically competitive with dental implants? Would it be possible to make regenerated teeth affordable by a large segment of the population worldwide? This review article explores existing and visionary approaches that address some of the above-mentioned questions. Tooth regeneration represents a revolution in stomatology as a shift in the paradigm from repair to regeneration: repair is by metal or artificial materials whereas regeneration is by biological restoration. Tooth regeneration is an extension of the concepts in the broad field of regenerative medicine to restore a tissue defect to its original form and function by biological substitutes. PMID:21789959

  9. 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

  10. Micromachined piezoresistive proximal probe with integrated bimorph actuator for aligned single ion implantation

    E-print Network

    . Other proposals include nitrogen- vacancy centers in diamond crystals,4 where recently single qubit in scanning probe cantilevers as small as 5 nm have been achieved by focused ion beam FIB drilling followed

  11. Twist1 Is Essential for Tooth Morphogenesis and Odontoblast Differentiation.

    PubMed

    Meng, Tian; Huang, Yanyu; Wang, Suzhen; Zhang, Hua; Dechow, Paul C; Wang, Xiaofang; Qin, Chunlin; Shi, Bing; D'Souza, Rena N; Lu, Yongbo

    2015-12-01

    Twist1 is a basic helix-loop-helix-containing transcription factor that is expressed in the dental mesenchyme during the early stages of tooth development. To better delineate its roles in tooth development, we generated Twist1 conditional knockout embryos (Twist2(Cre) (/+);Twist1(fl/fl)) by breeding Twist1 floxed mice (Twist1(fl/fl)) with Twist2-Cre recombinase knockin mice (Twist2(Cre) (/+)). The Twist2(Cre) (/+);Twist1(fl/fl) embryos formed smaller tooth germs and abnormal cusps during early tooth morphogenesis. Molecular and histological analyses showed that the developing molars of the Twist2(Cre) (/+);Twist1(fl/fl) embryos had reduced cell proliferation and expression of fibroblast growth factors 3, 4, 9, and 10 and FGF receptors 1 and 2 in the dental epithelium and mesenchyme. In addition, 3-week-old renal capsular transplants of embryonic day 18.5 Twist2(Cre) (/+);Twist1(fl/fl) molars showed malformed crowns and cusps with defective crown dentin and enamel. Immunohistochemical analyses revealed that the implanted mutant molars had defects in odontoblast differentiation and delayed ameloblast differentiation. Furthermore, in vitro ChIP assays demonstrated that Twist1 was able to bind to a specific region of the Fgf10 promoter. In conclusion, our findings suggest that Twist1 plays crucial roles in regulating tooth development and that it may exert its functions through the FGF signaling pathway. PMID:26487719

  12. 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

  13. Implant isotopy (II).

    PubMed

    Muratori, G

    1995-01-01

    Because nature has given humans from 14 to 16 teeth per arch, the author maintains that an implantologist ought to replace each missing tooth with an implant and calls this philosophical creed "implant isotopy". Three different prosthetic solutions are suggested for the cases of either complete or partially edentulous arches, where from 12 to 14 abutments are emerging from the gingiva. The first type consists of parallel protruding posts. The second type is a modification of the first method through the connection of all the posts (although they are not perfectly parallel) via a titanium wire-drawn bar to be welded via endoral welding. Finally, the third type consists of a laboratory cast titanium denture composed of different sections that can be connected to one another and to the implant abutments via endoral welding. PMID:7473871

  14. Cross-sectional transmission electron microscopy method and studies of implant damage in single crystal diamond

    E-print Network

    Florida, University of

    crystal diamond D. P. Hickey,a E. Kuryliw, K. Siebein, and K. S. Jones Materials Science and Engineering microscopy TEM studies of single crystal diamond have been reported, most likely due to the time crystal diamond using a focused ion beam and in situ lift-out. The method results in samples approximately

  15. Eleven-year study of hydroxyapatite implants.

    PubMed

    Denissen, H W; Kalk, W; Veldhuis, A A; van den Hooff, A

    1989-06-01

    An 11-year clinical research study was conducted with both unloaded bulk hydroxyapatite implants and loaded hydroxyapatite-coated titanium implants. A total of 102 submerged bulk hydroxyapatite implants were placed after extraction of teeth to maintain the volume of the residual alveolar ridge by their physical presence. All 21 implants under fixed partial dentures and 51 of 81 implants under lower complete dentures remained submucosal. A total of 71 hydroxyapatite-coated titanium implants were connected with permucosal superstructures by use of a two-stage method. Modifications in design and in implantation technique were required. This long-term research indicates that cylindrical hydroxyapatite implants are reliable devices as natural tooth root substitutes that bond directly to bone instead of simply being osseointegrated. PMID:2657029

  16. 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.

  17. Annealing-environment effects on the properties of CoPt nanoparticles formed in single-crystal Al2O3 by ion implantation

    NASA Astrophysics Data System (ADS)

    White, C. W.; Withrow, S. P.; Budai, J. D.; Thomas, D. K.; Williams, J. M.; Meldrum, A.; Sorge, K. D.; Thompson, J. R.; Ownby, G. W.; Wendelken, J. F.; Boatner, L. A.

    2005-12-01

    The ion implantation of nearly equal doses of Co and Pt into a single-crystal Al2O3 host followed by thermal annealing leads to the formation of nanoparticles whose phase, structure, and physical properties are strongly dependent on the annealing environment. Annealing in 96%Ar+4%H2 gives rise to ferromagnetic, chemically ordered CoPt nanoparticles with the L10 structure and a magnetic coercivity that can exceed 10kOe at 5K. Annealing in O2 (or in Ar) does not result in the formation of a CoPt alloy. Instead, the implanted Pt precipitates to form oriented elemental Pt nanoparticles, and the implanted Co combines with oxygen to form Co3O4 oxide nanoparticles. Annealing in ultrahigh-vacuum conditions results in a mixture of phases including CoPt3 and Co3O4 and possibly Co. The results obtained for Co +Pt-implanted Al2O3 are compared with the previous results for Fe +Pt-implanted Al2O3 annealed in similar environments.

  18. Charcot-Marie-Tooth disease

    MedlinePLUS

    Charcot-Marie-Tooth disease is a group of disorders passed down through families that affect the nerves outside the brain ... Charcot-Marie-Tooth disease slowly gets worse. Some parts of the body may become numb, and pain can range from ...

  19. 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

  20. Breast Implants

    MedlinePLUS

    ... ALCL) in women with breast implants. Outline the regulatory history of breast implants in the United States. ... Freedom of Information Requests More in Breast Implants Regulatory History of Breast Implants in the U.S. Saline- ...

  1. 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

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

    PubMed

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

    2014-07-01

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

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

    PubMed

    Cordeiro, Wayne José Batista; do Couto, Cintia Fernandes; Barros, Renata Nunes; Zarranz, Laila; Jorge, Mônica Zacharias; de Gouvêa, Cresus Vínicius 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

  5. 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

  6. 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 5 mm 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

  7. A Murine Model of Lipopolysaccharide-Induced Peri-Implant Mucositis and Peri-Implantitis.

    PubMed

    Pirih, Flavia Q; Hiyari, Sarah; Leung, Ho-Yin; Barroso, Ana D V; Jorge, Adrian C A; Perussolo, Jeniffer; Atti, Elisa; Lin, Yi-Ling; Tetradis, Sotirios; Camargo, Paulo M

    2015-10-01

    Dental implants are a widely used treatment option for tooth replacement. However, they are susceptible to inflammatory diseases such as peri-implant mucositis and peri-implantitis, which are highly prevalent and may lead to implant loss. Unfortunately, the understanding of the pathogenesis of peri-implant mucositis and peri-implantitis is fragmented and incomplete. Therefore, the availability of a reproducible animal model to study these inflammatory diseases would facilitate the dissection of their pathogenic mechanisms. The objective of this study is to propose a murine model of experimental peri-implant mucositis and peri-implantitis. Screw-shaped titanium implants were placed in the upper healed edentulous alveolar ridges of C57BL/6J mice 8 weeks after tooth extraction. Following 4 weeks of osseointegration, Porphyromonas gingivalis -lipolysaccharide (LPS) injections were delivered to the peri-implant soft tissues for 6 weeks. No-injections and vehicle injections were utilized as controls. Peri-implant mucositis and peri-implantitis were assessed clinically, radiographically (microcomputerized tomograph [CT]), and histologically following LPS-treatment. LPS-injections resulted in a significant increase in soft tissue edema around the head of the implants as compared to the control groups. Micro-CT analysis revealed significantly greater bone loss in the LPS-treated implants. Histological analysis of the specimens demonstrated that the LPS-group had increased soft tissue vascularity, which harbored a dense mixed inflammatory cell infiltrate, and the bone exhibited noticeable osteoclast activity. The induction of peri-implant mucositis and peri-implantitis in mice via localized delivery of bacterial LPS has been demonstrated. We anticipate that this model will contribute to the development of more effective preventive and therapeutic approaches for these 2 conditions. PMID:24967609

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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…

  13. 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 ...

  14. 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

  15. 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.

  16. 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

  17. Tooth polishing: The current status.

    PubMed

    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

  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. [Role of inheritability of tooth form, tooth malformation and tooth position].

    PubMed

    Carels, C; Vlietinck, R

    1999-08-01

    A common technique to divide the influence of heredity and environment on certain characteristics, or pathologies is the one that uses twins. There are more or less complex techniques to carry out twin research, from which the most simple procedure consists of determining the amount of concordance of certain characteristics in monozygotic (MZ) and dizygotic (DZ) twins. In individuals who develop from one oocyte, like MZ twins, one would expect a correlation of 1.00 (or 100% concordance) purely from their gene-relation. DZ twins are the result of separate conceptions of the same parents and they thus differ as much from each other as ordinary brothers and sisters. The most recently developed twin-methodologies use path analysis and model fitting for the estimations of the heritabilities and environmental influences on certain characteristics. In this article it is tried to picture the genetic an environmental influence on tooth form, tooth position and occlusal characteristics with different genetic techniques. Generally it can be concluded that our genes are of utmost importance for tooth form and tooth malformations, but the environment has a much bigger impact on tooth position and occlusal parameters. PMID:11930424

  20. Osteoimmunology in orthodontic tooth movement.

    PubMed

    Jiang, C; Li, Z; Quan, H; Xiao, L; Zhao, J; Jiang, C; Wang, Y; Liu, J; Gou, Y; An, S; Huang, Y; Yu, W; Zhang, Y; He, W; Yi, Y; Chen, Y; Wang, J

    2015-09-01

    The skeletal and immune systems share a multitude of regulatory molecules, including cytokines, receptors, signaling molecules, and signaling transducers, thereby mutually influencing each other. In recent years, several novel insights have been attained that have enhanced our current understanding of the detailed mechanisms of osteoimmunology. In orthodontic tooth movement, immune responses mediated by periodontal tissue under mechanical force induce the generation of inflammatory responses with consequent alveolar bone resorption, and many regulators are involved in this process. In this review, we take a closer look at the cellular/molecular mechanisms and signaling involved in osteoimmunology and at relevant research progress in the context of the field of orthodontic tooth movement. PMID:25040955

  1. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  2. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  3. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  4. 21 CFR 872.3920 - Porcelain tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  5. Palatal implants in the treatment of obstructive sleep apnea: a randomised, placebo-controlled single-centre trial.

    PubMed

    Maurer, J T; Sommer, J U; Hein, G; Hörmann, K; Heiser, C; Stuck, Boris A

    2012-07-01

    Palatal implants have been used to treat snoring and mild to moderate obstructive sleep apnea (OSA). Two previous controlled trials have published conflicting results regarding the effects of palatal implants on objective outcome measures, although they both could demonstrate superiority over placebo. The aim of the present study was to assess the effects of palatal implants in patients with mild to moderate sleep apnea in a randomised, placebo-controlled trial. Twenty-two patients with mild to moderate OSA (AHI 18 ± 5, BMI 28 ± 3, age 51 ± 13 years) due to palatal obstruction were enrolled in this randomised, double-blind, placebo-controlled trial. Respiratory parameters and sleep efficiency (evaluated by polysomnography), snoring (evaluated by the bed partner), and daytime sleepiness (evaluated by ESS) were assessed before and 90 days after surgery. One patient in each group did not show up for follow-up. The AHI, HI and LSAT showed statistically significant improvement in the treatment group (p < 0.05). Snoring as rated by bed partners also showed statistically significant improvement within the treatment group (p = 0.025). There was no statistical difference when comparing the means of the treatment group with the placebo group. There were no peri- or post-operative complications and no extrusions during the follow-up period. The study supports the idea that palatal implants lead to a reduction in respiratory events in patients with mild to moderate OSA, although a statistically significant superiority of palatal implants over placebo could not be demonstrated in this trial. PMID:22228439

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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

  12. 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 ...

  13. 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

  14. 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.

  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. 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

  17. DISCUSSION ON THE PULPLESS TOOTH

    PubMed Central

    1928-01-01

    A large proportion of the population have pulpless teeth, hence the importance of this subject. The main principles concerned in the treatment of pulpless teeth are: the removal of the pulp in its entirety, the drainage of the stump of the severed pulp, the cleansing and drying of the root canals and the filling of the tooth cavity. Local anæsthesia is preferable to caustics for desensitizing the tooth pulp prior to its removal. Antiseptics used in a dry condition are preferable to those used in a moist condition for root canal treatment. Nothing is gained by filling the root canals, if the peri-apical tissues have scarred there is no further discharge into these canals; and if they have not scarred the filling of the root canals will only obstruct drainage. If the discharge from the canals is copious, the tooth cavity should be left open to the mouth except for the insertion of a loosely placed dressing. Untreated pulpless teeth are more liable to give rise to “open” sepsis; treated pulpless teeth to “closed” sepsis. The crux of the question as to whether pulpless teeth should be retained or extracted is one of evaluating their advantages and disadvantages. A tooth deprived of its pulp owing to infective changes gives rise to subjective and objective symptoms and signs. A tooth deprived of its pulp owing to physiological changes gives rise to no apparent ill effects. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13Fig. 14Fig. 15Fig. 16 PMID:19986559

  18. 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

  19. 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

  20. Optical spectroscopy and tooth decay

    NASA Astrophysics Data System (ADS)

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

    2005-11-01

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

  1. 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.

  2. Tooth Size Variation Related to Age in Amboseli Baboons

    PubMed Central

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

    2011-01-01

    We measured the molar size from a single population of wild baboons from Amboseli (Kenya), both females (n = 57) and males (n = 50). All the females were of known age; the males represented a mix of known-age individuals (n = 31) and individuals with ages estimated to within 2 years (n = 19). The results showed a significant reduction in the mesiodistal length of teeth in both sexes as a function of age. Overall patterns of age-related change in tooth size did not change whether we included or excluded the individuals of estimated age, but patterns of statistical significance changed as a result of changed sample sizes. Our results demonstrate that tooth length is directly related to age due to interproximal wearing caused by M2 and M3 compression loads. Dental studies in primates, including both fossil and extant species, are mostly based on specimens obtained from osteological collections of varying origins, for which the age at death of each individual in the sample is not known. Researchers should take into account the phenomenon of interproximal attrition leading to reduced tooth size when measuring tooth length for ondontometric purposes. PMID:21325862

  3. 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 ...

  4. Cochlear implant

    MedlinePLUS

    ... antenna. This part of the implant receives the sound, converts the sound into an electrical signal, and sends it to ... implants allow deaf people to receive and process sounds and speech. However, it is important to understand ...

  5. 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

  6. Nuclear-chemical methods in a hard tooth tissue abrasion study

    NASA Astrophysics Data System (ADS)

    Gosman, A.; Sp?vá?ek, V.; Koní?ek, J.; Vopálka, D.; Hou?ová, D.; Doležalová, L.

    1999-01-01

    The advanced method consists in implantation—labelling of the thin surface layers of the solid objects, e.g. hard tooth tissue, by atoms of suitable natural or artificial radionuclides. Nuclides from the uranium series were implanted into the surface by using nuclear recoil effect at alpha decay of 226Ra to 222Rn, alpha decay of 222Rn to RaA, alpha decay of RaA to RaB (beta-emitter) and further alpha or beta emitters. With regard to chosen alpha detection and to the half—lives of the radionuclides, there was actually measured the activity of 222Rn, RaA and RaC’ in the thin surface layer. This was followed by the laboratory simulation of the abrasion in the system of “toothbrush—various suspensions of the tooth-pastes—hard tooth tissue (or material standard—ivory)” in specially designed device—the dentoabrasionmeter. The activities of the tissue surface measured before and after abrasion were used for calculations of the relative drop of the surface activity. On this basis the influence of various tooth-pastes containing various abrasive substances was determined.

  7. 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.

  8. Finite element-based force/moment-driven simulation of orthodontic tooth movement.

    PubMed

    Geiger, M

    2013-01-01

    The objectives of this study were to develop a numerically controlled experimental set-up to predict the movement caused by the force systems of orthodontic devices and to experimentally verify this system. The presented experimental set-up incorporated an artificial tooth fixed via a 3D force/moment sensor to a parallel kinematics robot. An algorithm determining the initial movement of the tooth in its elastic embedding controlled the set-up. The initial tooth movement was described by constant compliances. The constants were obtained prior to the experiment in a parameterised finite element (FE) study on the basis of a validated FE model of a human molar. The long-term tooth movement was assembled by adding up a multiple of incremental steps of initial tooth movements. A pure translational movement of the tooth of about 8 mm resulted for a moment to force ratio of - 8.85 mm, corresponding to the distance between the bracket and the centre of resistance. The correct behaviour of this linear elastic model in its symmetry plane allows for simulating single tooth movement induced by orthodontic devices. PMID:22292517

  9. 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

  10. Alternative management of a crown root fractured tooth in a child.

    PubMed

    Mackie, I C; Quayle, A A

    1992-07-25

    A crown root fracture of a tooth in a young person may necessitate the removal of the root and the placement of a space-maintaining partial denture followed by provision of a bridge. A case is reported of an alternative approach to treatment, in which the root fragment is retained in situ until the end of the pubertal growth spurt, in order to preserve alveolar bone, following which it is removed and replaced by an implant. PMID:1503835

  11. 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

  12. Immunomodulation Stimulates the Innervation of Engineered Tooth Organ

    PubMed Central

    Kökten, Tunay; Bécavin, Thibault; Keller, Laetitia; Weickert, Jean-Luc; Kuchler-Bopp, Sabine; Lesot, Hervé

    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

  13. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  14. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  15. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  16. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  17. 21 CFR 872.3580 - Preformed gold denture tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  18. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  19. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Preformed plastic denture tooth. 872.3590 Section...Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated...

  20. Biofilm and dental implant: The microbial link

    PubMed Central

    Dhir, Sangeeta

    2013-01-01

    Mouth provides a congenial environment for the growth of the microorganisms as compared to any other part of the human body by exhibiting an ideal nonshedding surface. Dental plaque happens to be a diverse community of the microorganisms found on the tooth surface. Periodontal disease and the peri-implant disease are specific infections that are originating from these resident microbial species when the balance between the host and the microbial pathogenicity gets disrupted. This review discusses the biofilms in relation to the peri-implant region, factors affecting its presence, and the associated treatment to manage this complex microbial colony. Search Methodology: Electronic search of the medline was done with the search words: Implants and biofilms/dental biofilm formation/microbiology at implant abutment interface/surface free energy/roughness and implant, periimplantitis/local drug delivery and dental implant. Hand search across the journals – clinical oral implant research, implant dentistry, journal of dental research, international journal of oral implantology, journal of prosthetic dentistry, perioodntology 2000, journal of periodontology were performed. The articles included in the review comprised of in vivo studies, in vivo (animal and human) studies, abstracts, review articles. PMID:23633764

  1. Oxygen implanter for simox

    NASA Astrophysics Data System (ADS)

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

    1985-01-01

    Interest in silicon or) insulator (SOI) technology has led to the development of several alternatives to silicon on sapphire. One of the most promising techniques makes use of an ion implanter to form a buried oxide layer directly in the silicon substrate. To have useful single crystalline silicon on top of the oxide layer, it is necessary to do the implant at high wafer temperatures and rely on solid phase epitaxy to maintain surface structure. A high current, 160 keV, Nova ion implanter has been adapted to provide the ability to perform oxygen implants at elevated temperatures. The operator is free to choose any temperature in the range between 400°C and 600°C. The system then preheats the wafers to the selected temperature before the implant begins. A novel technique for providing both heating and cooling capability to the end station is employed. An infrared signal from the wafers is monitored by a room temperature lead salt detector. This signal is then used by a servo-loop to control the heating of the end station and to maintain the wafer temperature to within ± 20°C during the implant. High doses of the type necessary to form a silicon dioxide buried layer require long lived, high current oxygen sources. An oxygen source has been specially developed, which provides as much as 10 mA of ion current. At a 6 mA output, source lifetimes in excess of 40 hours have been achieved. The implanter uses a specifically designed high temperature disk, which holds ten wafers, each of four inch diameter. A variety of implant angles lying between 0° and 15° is available. The beam is scanned mechanically and an electron flood gun can be used to prevent wafer charging. Special thermal barriers have been employed to protect the apparatus from extreme temperatures and to make the heating sequence more efficient and more rapid. Every effort has been made to avoid contamination of the implant. The implant disk, for example, is overcoated with silicon monoxide. Silicon apertures have also been designed for the machine. The implanter has been used to do a high current oxygen implant with a dose of 1.25 × 10 18/cm 2, at a temperature of 570°C. Preliminary analysis of the results is very promising.

  2. 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.

  3. Tooth whitening: facts and fallacies.

    PubMed

    Heymann, H O

    2005-04-23

    Since the introduction of nightguard vital bleaching (tray bleaching) in 1989, dentistry has witnessed an astronomical rise in the interest in tooth whitening.(1) As a result, the most frequently asked question is, 'what bleaching technique works best?' Virtually all of today's whitening approaches work, because bleach is bleach. Whether a nightguard bleach is used with only 10% carbamide peroxide (which contains only 3% hydrogen peroxide), over-the-counter (OTC) whitening strips are applied containing 6% hydrogen peroxide, or an in-office bleach is employed using 25-35% hydrogen peroxide, the end results can potentially be the same. Similarity of results is possible because the mechanism of action is the same: oxidation of organic pigments or chromogens in the tooth. Granted, some bleaching approaches are more expeditious than others, owing to differences in concentration or exposure time. But as just noted, the most important factors in the efficacy of any bleaching treatment are concentration of the bleaching agent and duration of the exposure time. PMID:15849600

  4. 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

  5. Graphene-based wireless bacteria detection on tooth enamel

    NASA Astrophysics Data System (ADS)

    Mannoor, Manu S.; Tao, Hu; Clayton, Jefferson D.; Sengupta, Amartya; Kaplan, David L.; Naik, Rajesh R.; Verma, Naveen; Omenetto, Fiorenzo G.; McAlpine, Michael C.

    2012-03-01

    Direct interfacing of nanosensors onto biomaterials could impact health quality monitoring and adaptive threat detection. Graphene is capable of highly sensitive analyte detection due to its nanoscale nature. Here we show that graphene can be printed onto water-soluble silk. This in turn permits intimate biotransfer of graphene nanosensors onto biomaterials, including tooth enamel. The result is a fully biointerfaced sensing platform, which can be tuned to detect target analytes. For example, via self-assembly of antimicrobial peptides onto graphene, we show bioselective detection of bacteria at single-cell levels. Incorporation of a resonant coil eliminates the need for onboard power and external connections. Combining these elements yields two-tiered interfacing of peptide-graphene nanosensors with biomaterials. In particular, we demonstrate integration onto a tooth for remote monitoring of respiration and bacteria detection in saliva. Overall, this strategy of interfacing graphene nanosensors with biomaterials represents a versatile approach for ubiquitous detection of biochemical targets.

  6. 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…

  7. 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.

  8. Biologically Based Restorative Management of Tooth Wear

    PubMed Central

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

    2012-01-01

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

  9. 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 manufacturer’s 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 manufacturer’s 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

  10. 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 0.05–113.75, 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

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

    PubMed Central

    2014-01-01

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

  12. [Tooth transplantation: an extra dimension in orthodontics].

    PubMed

    Dermaut, L R; De Pauw, G A M

    2002-01-01

    In the first part of the presentation, the content of orthodontics has been briefly explained by means of some clinical cases. The main part of the presentation consisted of discussing patient treatment by means of autogenous tooth transplantation with special emphasis on its indications and contra-indications. When a tooth transplantation is carried out properly, a success percentage of 90%, even forty years after treatment, can be expected. This high percentage has been reported in a recent study. The success of tooth transplantation is mainly due to the timing of the transplantation and the non-traumatic handling during surgery. According to the literature, the ideal moment for tooth transplantation is when half to three quarters of the root has been formed. One of the indications for tooth transplantation is the transplantation of a tooth in the cleft of a cleft palate patient. Two cleft palate patients have been presented in which tooth transplantation was carried out after bone grafting in the alveolar cleft. Finally some findings of a recent study, carried out at our department, dealing with cryopreservation of teeth before transplantation, has been presented. According to the findings of this study, cryopreservation, after removal of the pulp tissue does not inhibit the normal ingrowth of new pulp tissue after transplantation. PMID:12647580

  13. 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

  14. 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…

  15. 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

  16. 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

  17. 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

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

  19. [Biological basis of orthodontic tooth movement].

    PubMed

    Maltha, J C; van Leeuwen, E J

    2000-04-01

    The effect of orthodontic therapy is dependent of the biological possibilities and limitations of the dento-alveolar complex. Biomechanical effects determine the first phase of tooth movement. In the second phase hyalinisation occurs in almost all cases. Elimination of the hyalinised tissue is associated with undermining bone resorption. Next, 'real' tooth movement starts. At the pressure side the normal structure of the periodontal ligament is destroyed and so is the tooth attachment. At the tension side deposition of trabecular bone is found and the tooth attachment remains. The regulation of these processes is still not completely understood, but cytokines and growth factors play an important role. The biological system does not react according to a simple dose-response relation and large individual differences in susceptibility of the system exist. PMID:11382966

  20. 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-André; 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 (78.1±6.7 vs. 66.2±13.1, P<0.001; 27.4±18.7 vs. 14.4±10, P<0.001; and 49.8±13.1 vs. 56.7±15.8, 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 0.9±1.0 vs. 0.6±0.9, 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

  1. 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

  2. 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

  3. 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

  4. [Immediate replacement of missing lower front teeth using Denti One-Piece and needle implants].

    PubMed

    Mihály, Orosz

    2009-12-01

    The Denti one-stage root form implant made of pure titanium (so called DOP implant type) was introduced in 2004 and the Denti Needle implants was introduced in 2007. The author of this paper was one of the first who used these systems in Hungary. The observation period of the implanted DOP implants ranges between 1 to 5 years with a success rate of 95.1%. So far, only a small number of these type of implants have been placed, with an observation period of 1 to 5 years, therefore statistical analysis could not be made. Clinical experiences obtained during the course of the use of these implants are most favourably primarily because of their easy use and special indication (small volume of vestibulo-oralis bone). In this way these implants are especially suitable for the replacement of missing front tooth. PMID:20198993

  5. Cochlear Implants

    MedlinePLUS

    ... or after the patient developed language skills The motivation of the patient and his or her family ... from a cochlear implant and will have the motivation to participate in the process. It is important ...

  6. Cochlear Implants

    MedlinePLUS

    ... under the skin behind the ear, connected to electrodes that are inserted inside the cochlea. An external ... stimulator then sends the signals to the implanted electrodes in the cochlea. The electrodes? signals stimulate the ...

  7. 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

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

    PubMed

    Kamburo?lu, K?vanç; Gül?ah?, Ay?e; Genç, 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

  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. 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

  11. 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

  12. 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

  13. 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

  14. The dual-zone therapeutic concept of managing immediate implant placement and provisional restoration in anterior extraction sockets.

    PubMed

    Chu, Stephen J; Salama, Maurice A; Salama, Henry; Garber, David A; Saito, Hanae; Sarnachiaro, Guido O; Tarnow, Dennis P

    2012-01-01

    Improvements in implant designs have helped advance successful immediate anterior implant placement into fresh extraction sockets. Clinical techniques described in this case enable practitioners to achieve predictable esthetic success using a method that limits the amount of buccal contour change of the extraction site ridge and potentially enhances the thickness of the peri-implant soft tissues coronal to the implant-abutment interface. This approach involves atraumatic tooth removal without flap elevation, and placing a bone graft into the residual gap around an immediate fresh-socket anterior implant with a screw-retained provisional restoration acting as a prosthetic socket seal device. PMID:22908601

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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

  20. Tooth-derived bone graft material

    PubMed Central

    Kim, Young-Kyun; Lee, Junho; Kim, Kyung-Wook; Murata, Masaru; Akazawa, Toshiyuki; Mitsugi, Masaharu

    2013-01-01

    With successful extraction of growth factors and bone morphogenic proteins (BMPs) from mammalian teeth, many researchers have supported development of a bone substitute using tooth-derived substances. Some studies have also expanded the potential use of teeth as a carrier for growth factors and stem cells. A broad overview of the published findings with regard to tooth-derived regenerative tissue engineering technique is outlined. Considering more than 100 published papers, our team has developed the protocols and techniques for processing of bone graft material using extracted teeth. Based on current studies and studies that will be needed in the future, we can anticipate development of scaffolds, homogenous and xenogenous tooth bone grafts, and dental restorative materials using extracted teeth. PMID:24471027

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

    PubMed

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

    2014-08-01

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

  2. 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

  3. A 3-year follow-up study of all-ceramic single and multiple crowns performed in a private practice: a prospective case series

    PubMed Central

    Tartaglia, Gianluca M.; Sidoti, Ernesto; Sforza, Chiarella

    2011-01-01

    OBJECTIVES: Zirconia-based prostheses are commonly used for aesthetic crown and fixed restorations, although follow-up data are limited, especially for implant-supported crowns. The aim of this study was to evaluate the three-year clinical results of the installation of 463 zirconia core crowns by a general dental private practice. METHODS: This study followed 142 patients (69 men and 73 women; aged 28-82 years) who had received 248 single crowns (202 tooth-supported, 36 implant-supported) and 225 multiple units of up to six elements (81 tooth-supported, 144 implant-supported). Clinical events, including fracture and loss of retention, secondary caries, and marginal integrity, were recorded. The overall failure rate was computed for the fractured and lost prostheses. Aesthetic, functional, and biological properties were rated, and patient satisfaction was investigated. RESULTS: During the three-year follow-up period, four patients were lost from the study (18 crowns, 4% of the total crowns). Three of the zirconia prostheses suffered fractures in more than three units (11 crowns; one- vs. three-year follow-up, p<0.05, Wilcoxon signed-rank test), and the cumulative prosthesis survival rate was 98.2%. Twelve units lost retention and were re-cemented, and no secondary caries of the abutment teeth were reported. The aesthetic, functional, and biological properties were generally well-rated, and there were no differences between tooth- and implant-supported crowns. The lowest scores were given regarding the anatomical form of the crowns, as some minor chipping was reported. Relatively low scores were also given for the periodontal response and the adjacent mucosa. Overall, patient satisfaction was high. CONCLUSIONS: At the three-year follow-up, the zirconia-core crowns appeared to be an effective clinical solution as they had favorable aesthetic and functional properties. Only the marginal fit of the prostheses should be improved upon. PMID:22189731

  4. 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.

  5. Charcot-Marie-Tooth disease and vincristine.

    PubMed

    Orejana-García, Angel M; Pascual-Huerta, Javier; Pérez-Melero, Andrés

    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

  6. Aesthetic Rehabilitation of a Complicated Crown-Root Fracture of the Maxillary Incisor: Combination of Orthodontic and Implant Treatment

    PubMed Central

    de Avila, Érica Dorigatti; de Molon, Rafael Scaf; Cardoso, Mauricio de Almeida; Capelozza Filho, Leopoldino; Campos Velo, Marilia Mattar de Amoêdo; Mollo, Francisco de Assis; Borelli Barros, Luiz Antonio

    2014-01-01

    The aim of this paper is to present a complex rehabilitation, of fractured tooth, with implants in anterior region considering the orthodontics extrusion to clinical success. At 7 years old, the patient fractured the maxillary left central incisor and the dentist did a crown with the fragment. Twenty years later, the patient was referred to a dental clinic for orthodontic treatment, with the chief complaint related to an accentuated deep bite, and a professional started an orthodontic treatment. After sixteen months of orthodontic treatment, tooth 21 fractured. The treatment plan included an orthodontic extrusion of tooth 21 and implant placement. This case has been followed up and the clinical and radiographic examinations show excellence esthetic results and satisfaction of patient. The forced extrusion can be a viable treatment option in the management of crown root fracture of an anterior tooth to gain bone in a vertical direction. This case emphasizes that to achieve the esthetic result a multidisciplinary approach is necessary. PMID:24872900

  7. 21 CFR 872.3200 - Resin tooth bonding agent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a) Identification. A resin tooth bonding agent is a...

  8. Seal Out Tooth Decay: A Fact Sheet for Parents

    MedlinePLUS

    ... Institute of Dental and Craniofacial Research Seal Out Tooth Decay A Fact Sheet for Parents What are dental ... important reason for getting sealants is to avoid tooth decay. • Fluoride in toothpaste and in drinking water protects ...

  9. 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

  10. Etiology and management of whitening-induced tooth hypersensitivity.

    PubMed

    Hewlett, Edmond R

    2007-07-01

    Tooth hypersensitivity has long been, and continues to be, the most commonly reported adverse effect of vital tooth whitening with peroxide gels. The complex etiology of whitening-induced tooth hypersensitivity has been a major obstacle in developing a definitive strategy for its prevention. This article reviews the multiple etiologic factors implicated in whitening-induced tooth hypersensitivity and the evidence for efficacy of various strategies for its management. PMID:17915592

  11. 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.

  12. Visual outcome of pars plana vitrectomy with intraocular foreign body removal through sclerocorneal tunnel and sulcus-fixated intraocular lens implantation as a single procedure, in cases of metallic intraocular foreign body with traumatic cataract

    PubMed Central

    Mahapatra, Santosh K; Rao, Nageswar G

    2010-01-01

    Aim: To evaluate visual outcome following pars plana vitrectomy (PPV) and intraocular foreign body (IOFB) removal through the sclerocorneal tunnel combined with simultaneous cataract extraction and sulcus-fixated intraocular lens (IOL) implantation as a single procedure in penetrating ocular trauma with IOFB and traumatic cataract. Materials and Methods: Eighteen cases of penetrating ocular trauma with retained IOFB and traumatic cataract who underwent PPV, IOFB body removal and cataract extraction with posterior chamber IOL (PCIOL) implantation in the same sitting, between June '04 and December '05 were retrospectively analyzed. All the foreign bodies were removed through the sclerocorneal tunnel. Result: All the 18 patients were young males, with an average follow-up period of 12 months. In 12 cases the foreign body was intravitreal and in six cases it was intraretinal but extramacular. Thirteen cases had a best corrected visual acuity ranging from 20/20 to 20/60 at their last follow-up. Five cases developed retinal detachment due to proliferative vitreoretinopathy (PVR) changes postoperatively and were subsequently managed by surgery. Conclusion: Primary IOL implantation with combined cataract and vitreo-retinal surgery is a safe option reducing the need for two separate surgeries in selected patients with retained IOFB and traumatic cataract. This combined procedure provides good visual outcome with early rehabilitation in young working patients. PMID:20195033

  13. 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...

  14. 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...

  15. 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...

  16. 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…

  17. 21 CFR 872.3200 - Resin tooth bonding agent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Resin tooth bonding agent. 872.3200 Section 872.3200...Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a) Identification. A resin tooth bonding agent is a device material, such...

  18. 21 CFR 872.3200 - Resin tooth bonding agent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Resin tooth bonding agent. 872.3200 Section 872.3200...Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a) Identification. A resin tooth bonding agent is a device material, such...

  19. Correspondence between tooth shape and dietary biomechanical properties in insectivorous

    E-print Network

    Evans, Alistair

    : The following three factors may cause discrepancies in tooth form in animals with different diets: (1) optional functional form; (2) risk of tooth fracture; and (3) amount of wear. Data studied: Functional parameters to be lower. The differences found arguably relate more to the risk of tooth fracture and increased wear

  20. 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...

  1. 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...

  2. 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...

  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.

  4. 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

  5. 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.

  6. 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

  7. Neurologic Regulation and Orthodontic Tooth Movement.

    PubMed

    Kyrkanides, Stephanos; Huang, Hechang; Faber, Richard D

    2015-01-01

    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

  8. 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

  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. Life of a Tooth: A Visual Timeline

    MedlinePLUS Videos and Cool Tools

    Dental care and oral health information you need from the Academy of General Dentistry Saturday, January 09, 2016 About | Contact InfoBites Quick Reference ... Learn more Children's Oral Health Check Menstrual Calendar for Tooth Extraction What is a Composite Resin (White Filling)? How Do I Care for My Child's Baby Teeth? Men: Looking for ...

  11. Contribution of donor and host mesenchyme to the transplanted tooth germs.

    PubMed

    Nakaki, T; Saito, K; Ida-Yonemochi, H; Nakagawa, E; Kenmotsu, S; Ohshima, H

    2015-01-01

    Autologous tooth germ transplantation of immature teeth is an alternative method of tooth replacement that could be used instead of dental implants in younger patients. However, it is paramount that the dental pulp remain vital and that root formation continue in the transplanted location. The goal of this study is to characterize the healing of allogenic tooth grafts in an animal model using GFP-labeled donor or host postnatal mice. In addition, the putative stem cells were labeled before transplantation with a pulse-chase paradigm. Transplanted molars formed cusps and roots and erupted into occlusion by 2 wk postoperatively. Host label-retaining cells (LRCs) were maintained in the center of pulp tissue associating with blood vessels. Dual labeling showed that a proportion of LRCs were incorporated into the odontoblast layer. Host cells, including putative dendritic cells and the endothelium, also immigrated into the pulp tissue but did not contribute to the odontoblast layer. Therefore, LRCs or putative mesenchymal stem cells are retained in the transplanted pulps. Hertwig's epithelial root sheath remains vital, and epithelial LRCs are present in the donor cervical loops. Thus, the dynamic donor-host interaction occurred in the developing transplant, suggesting that these changes affect the characteristics of the dental pulp. PMID:25376722

  12. 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

  13. 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

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

    PubMed Central

    Taylor, Lucy A.; Kaiser, Thomas M.; Schwitzer, Christoph; Müller, 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

  15. [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

  16. 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.

  17. 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

  18. 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

  19. Hip Implant Systems

    MedlinePLUS

    ... Devices Products and Medical Procedures Implants and Prosthetics Metal-on-Metal Hip Implants Hip Implants Share Tweet Linkedin Pin ... devices available with different bearing surfaces. These are: Metal-on-Polyethylene: The ball is made of metal ...

  20. 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

  1. Tooth reorientation affects tooth function during prey processing and tooth ontogeny in the lesser electric ray, Narcine brasiliensis.

    PubMed

    Dean, Mason N; Ramsay, Jason B; Schaefer, Justin T

    2008-01-01

    The dental anatomy of elasmobranch fishes (sharks, rays and relatives) creates a functional system that is more dynamic than that of mammalian dentition. Continuous dental replacement (where new teeth are moved rostrally to replace older ones) and indirect fibrous attachment of the dentition to the jaw allow teeth to reorient relative to the jaw over both long- and short-term scales, respectively. In this study, we examine the processing behavior and dental anatomy of the lesser electric ray Narcine brasiliensis (Olfers, 1831) to illustrate that the freedom of movement of elasmobranch dentition allows a functional flexibility that can be important for complex prey processing behaviors. From static manipulations of dissected jaws and observations of feeding events in live animals, we show that the teeth rotate during jaw protrusion, resulting in a secondary grasping mechanism that likely serves to hold prey while the buccal cavity is flushed free of sediment. The function of teeth is not always readily apparent from morphology; in addition to short-term reorientation, the long-term dental reorientation during replacement allows a given tooth to serve multiple functions during tooth ontogeny. Unlike teeth inside the mouth, the cusps of external teeth (on the portion of the tooth pad that extends past the occlusal plane) lay flat, such that the labial faces act as a functional battering surface, protecting the jaws during prey excavation. PMID:18226886

  2. 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

  3. 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

  4. Minimizing bone gaps when using custom pediatric cranial implants is associated with implant success.

    PubMed

    Bowers, Christian A; McMullin, Jaron H; Brimley, Cameron; Etherington, Linsey; Siddiqi, Faizi A; Riva-Cambrin, Jay

    2015-10-01

    OBJECT Occasionally after a craniotomy, the bone flap is discarded (as in the case of osteomyelitis) or is resorbed (especially after trauma), and an artificial implant must be inserted in a delayed fashion. Polyetheretherketone (PEEK) implants and hard-tissue replacement patient-matched implants (HTR-PMI) are both commonly used in such cases. This study sought to compare the failure rate of these 2 implants and identify risk factors of artificial implant failure in pediatric patients. METHODS This was a retrospective cohort study examining all pediatric patients who received PEEK or HTR-PMI cranioplasty implants from 2000 to 2013 at a single institution. The authors examined the following variables: age, sex, race, mechanism, surgeon, posttraumatic hydrocephalus, time to cranioplasty, bone gap width, and implant type. The primary outcome of interest was implant failure, defined as subsequent removal and replacement of the implant. These variables were analyzed in a bivariate statistical fashion and in a multivariate logistic regression model for the significant variables. RESULTS The authors found that 78.3% (54/69) of implants were successful. The mean patient age was 8.2 years, and a majority of patients were male (73%, 50/69); the mean follow-up for the cohort was 33.3 months. The success rate of the 41 HTR-PMI implants was 78.1%, and the success rate of the 28 PEEK implants was 78.6% (p = 0.96). Implants with a bone gap of > 6 mm were successful in 33.3% of cases, whereas implants with a gap of < 6 mm had a success rate of 82.5% (p = 0.02). In a multivariate model with custom-type implants, previous failed custom cranial implants, time elapsed from previous cranioplasty attempt, and bone gap size, the only independent risk factor for implant failure was a bone gap > 6 mm (odds ratio 8.3, 95% confidence interval 1.2-55.9). CONCLUSIONS PEEK and HTR-PMI implants appear to be equally successful when custom implantation is required. A bone gap of > 6 mm with a custom implant in children results in significantly higher artificial implant failure. PMID:26161719

  5. Sensitivity of tooth enamel to penetrating radiation

    SciTech Connect

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

    1994-04-01

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

  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. Tooth wear: the view of the anthropologist.

    PubMed

    Kaidonis, John A

    2008-03-01

    Anthropologists have for many years considered human tooth wear a normal physiological phenomenon where teeth, although worn, remain functional throughout life. Wear was considered pathological only if pulpal exposure or premature tooth loss occurred. In addition, adaptive changes to the stomatognathic system in response to wear have been reported including continual eruption, the widening of the masticatory cycle, remodelling of the temporomandibular joint and the shortening of the dental arches from tooth migration. Comparative studies of many different species have also documented these physiological processes supporting the idea of perpetual change over time. In particular, differential wear between enamel and dentine was considered a physiological process relating to the evolution of the form and function of teeth. Although evidence of attrition and abrasion has been known to exist among hunter-gatherer populations for many thousands of years, the prevalence of erosion in such early populations seems insignificant. In particular, non-carious cervical lesions to date have not been observed within these populations and therefore should be viewed as 'modern-day' pathology. Extrapolating this anthropological perspective to the clinical setting has merits, particularly in the prevention of pre-mature unnecessary treatment. PMID:17938977

  8. 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

  9. 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.

  10. [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

  11. 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

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  13. 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.

  14. Short-term improvement of masticatory function after implant restoration

    PubMed Central

    2015-01-01

    Purpose Dental implants present several advantages over other tooth replacement options. However, there has been little research on masticatory function in relation to implant treatment. Therefore, the aim of the present study was to evaluate the improvement of masticatory function two weeks after implant restoration. Methods Masticatory ability was evaluated with the subjective food intake ability (FIA) and objective mixing ability index (MAI) methods. Fifty-four subjects with first and second missing molars completed the study. The subjects were asked to complete a self-reported questionnaire about 30 different food items, and to chew wax samples 10 times both before and two weeks after implant restoration. A total of 108 waxes were analyzed with an image analysis program. Results Dental implant restoration for lost molar teeth on one side increased the FIA score by 9.0% (P<0.0001). The MAI score also increased, by 14.3% after implant restoration (P<0.0001). Comparison between the good and poor mastication groups, which were subdivided based on the median MAI score before implant restoration, showed that the FIA score of the poor group was enhanced 1.1-fold while its MAI score was enhanced 2.0-fold two weeks after an implant surgery. Conclusions Using the FIA and MAI assessment methods, this study showed that masticatory function was improved two weeks after implant restoration. In particular, the enhancement of masticatory function by implant restoration was greater in patients with relatively poor initial mastication than in those with good initial mastication.

  15. 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.

  16. Straight, semi-anatomic and anatomic TMJ implants: the influence of condylar geometry and bone fixation screws.

    PubMed

    Ramos, A; Completo, A; Relvas, C; Mesnard, M; Simões, J A

    2011-07-01

    A 3D finite element model of in vitro intact and implanted mandibles with different temporomandibular joints (TMJ) was analyzed. Three TMJ implant geometries were assessed. The displacements, stress and strain fields on the condyle were obtained for both simulated cases. Strains were also assessed near the screws that fixate the implant to the mandible. The geometry of the mandible was obtained through 3D digitalization of a synthetic model. The TMJ implants studied were modelled considering a commercial implant which was also used to create semi-anatomic and anatomic implants that were analyzed and to assess the influence of the geometry. Numerical finite element models were built and the implants were positioned by an experienced orofacial surgeon. All implants were fixed by four screws which were placed in the same position on the mandible. The boundary conditions were simulated considering the support on the incisive tooth, the loads of the five most important muscular forces and a 5mm mouth aperture. This study indicates that the deformation on the intact mandible was similar when an anatomic implant was considered in the implanted mandible. However, the anatomic geometry presented some problems concerning the implant integrity due to geometric variations. The geometry of TMJ implant also played a role relatively to the screws structural integration and bone fixation. The geometry of TMJ implant defines the necessary number of screws and position in the mandible fixation. PMID:20801667

  17. Retrograde peri-implantitis

    PubMed Central

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

    2010-01-01

    Retrograde peri-implantitis constitutes an important cause for implant failure. Retrograde peri-implantitis may sometimes prove difficult to identify and hence institution of early treatment may not be possible. This paper presents a report of four cases of (the implant placed developing to) retrograde peri-implantitis. Three of these implants were successfully restored to their fully functional state while one was lost due to extensive damage. The paper highlights the importance of recognizing the etiopathogenic mechanisms, preoperative assessment, and a strong postoperative maintenance protocol to avoid retrograde peri-implant inflammation. PMID:20922082

  18. [A new implant system for orbital prosthetic rehabilitation: "epiplating mono"].

    PubMed

    Schneider, M; Federspil, P A; Neumann, A; Schick, B

    2014-06-01

    A New Implant System for Orbital Prosthetic Rehabilitation: "Epiplating Mono" Prosthetic or episthetic rehabilitation of ear, eye and nose are currently most common performed using magnetic fixation. While at the beginning single implants have been used, now-a-days a more extended approach with plate fixation are recommended to enhance the stability of the anchored magnets. A newly designed implant system epiplating mono is presented that combines the structure of a single implant with additional fixation elements. In a pilot study this new implant system was used in 4 patients for prosthetic orbital rehabilitation. Further experiences with this new implant system are required necessitating long-term experiences of implant stability to define the value of the presented epiplating mono system for prosthetic rehabilitation. PMID:24863910

  19. 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.

  20. 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.

  1. 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

  2. [Ossification of the collagen implant].

    PubMed

    Walter, M; Müller, J M; Keller, H W; Brenner, U

    1985-12-01

    Native collagen type I was studied morphologically and fluorescent-histologically after implantation in bony defects. As criteria for revitalisation we used depth and density of immigration, type of immigrated cells, revascularisation, formation of new cartilage and bone. Furthermore the deposition of fluorochromes was studied. The maximum of cellular immigration was reached after 8 weeks and remained at this level for the period of observation. The implants were impregnated only with fibroblasts and fibrocytes, developing into chondroblasts, chondrocytes, osteoblasts and osteocytes. Only in one case basophilic round-cells could be seen. The centres of the implants were after 6 weeks rarely, after 8 weeks fully revascularized. Formation of new cartilage and bone could be seen after 6 weeks, increasing in number and extension during the observation-period. Osteoneogenesis was performed both by desmal and enchondral ossification, enchondral ossification much more in evidence. The deposition of fluorochromes could be seen in each implant. After 8 weeks fluorochromes could only be seen at the bone-implant interface, after 12 and 16 weeks even the centres were well impregnated. In a single case reossification in a control-rib could be seen as well morphologically as fluorescent-histologically. PMID:2868614

  3. 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

  4. 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 (?(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 (?(44)Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (?(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 ?(26)Mg, ?(13)C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that ?(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 ?(26)Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel ?(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

  5. 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 (?13C) 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 (?44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (?26Mg) 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 ?26Mg, ?13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that ?26Mg 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 ?26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel ?26Mg 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

  6. [Osseointegrated implants in adolescents. A three year study].

    PubMed

    Thilander, B; Odman, J; Gröndahl, K; Friberg, B

    1995-10-01

    In 15 adolescents (age 13.2 to 19.4 years) in the late dental stage implants (n = 27) were chosen to replace missing teeth due to congenital absence or trauma. The patients were followed for at least 3 years. No fixture losses occurred. Only minor loss of bone support at the fixture was observed, while adjacent tooth surfaces showed some loss. Infra-occlusion of the implant restorations was noticed in patients with residual craniofacial growth. Thus, the dental and skeletal maturation, and not the chronological age, must be taken into account to avoid infra-occlusion. Furthermore it is important to gain enough space for the fixture in the mesio-distal direction in order to avoid the risk of marginal bone loss at teeth adjacent to the implants. PMID:11837093

  7. Surface modification of sapphire by ion implantation

    SciTech Connect

    McHargue, C.J.

    1998-11-01

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

  8. 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

  9. Global Burden of Severe Tooth Loss

    PubMed Central

    Kassebaum, N.J.; Bernabé, E.; Dahiya, M.; Bhandari, B.; Murray, C.J.L.; Marcenes, W.

    2014-01-01

    The goal of the Global Burden of Disease 2010 Study has been to systematically produce comparable estimates of the burden of 291 diseases and injuries and their associated 1,160 sequelae from 1990 to 2010. We aimed to report here internally consistent prevalence and incidence estimates of severe tooth loss for all countries, 20 age groups, and both sexes for 1990 and 2010. The systematic search of the literature yielded 5,618 unique citations. After titles and abstracts were screened, 5,285 citations were excluded as clearly not relevant to this systematic review, leaving 333 for full-text review; 265 publications were further excluded following the validity assessment. A total of 68 studies—including 285,746 individuals aged 12 yr or older in 26 countries—were included in the meta-analysis using modeling resources of the Global Burden of Disease 2010 Study. Between 1990 and 2010, the global age-standardized prevalence of edentate people decreased from 4.4% (95% uncertainty interval: 4.1%, 4.8%) to 2.4% (95% UI: 2.2%, 2.7%), and incidence rate decreased from 374 cases per 100,000 person-years (95% UI: 347, 406) to 205 cases (95% UI: 187, 226). No differences were found by sex in 2010. Prevalence increased gradually with age, showing a steep increase around the seventh decade of life that was associated with a peak in incidence at 65 years. Geographic differences in prevalence, incidence, and rate of improvement from 1990 to 2010 were stark. Our review of available quality literature on the epidemiology of tooth loss shows a significant decline in the prevalence and incidence of severe tooth loss between 1990 and 2010 at the global, regional, and country levels. PMID:24947899

  10. Biomechanics and strain mapping in bone as related to immediately-loaded dental implants.

    PubMed

    Du, Jing; Lee, Ji-Hyun; Jang, Andrew T; Gu, Allen; Hossaini-Zadeh, Mehran; Prevost, Richard; Curtis, Donald A; Ho, Sunita P

    2015-09-18

    The effects of alveolar bone socket geometry and bone-implant contact on implant biomechanics, and resulting strain distributions in bone were investigated. Following extraction of lateral incisors on a cadaver mandible, implants were placed immediately and bone-implant contact area, stability implant biomechanics and bone strain were measured. In situ biomechanical testing coupled with micro X-ray microscopy (µ-XRM) illustrated less stiff bone-implant complexes (701-822N/mm) compared with bone-periodontal ligament (PDL)-tooth complexes (791-913N/mm). X-ray tomograms illustrated that the cause of reduced stiffness was due to limited bone-implant contact. Heterogeneous elemental composition of bone was identified by using energy dispersive X-ray spectroscopy (EDS). The novel aspect of this study was the application of a new experimental mechanics method, that is, digital volume correlation, which allowed mapping of strains in volumes of alveolar bone in contact with a loaded implant. The identified surface and subsurface strain concentrations were a manifestation of load transferred to bone through bone-implant contact based on bone-implant geometry, quality of bone, implant placement, and implant design. 3D strain mapping indicated that strain concentrations are not exclusive to the bone-implant contact regions, but also extend into bone not directly in contact with the implant. The implications of the observed strain concentrations are discussed in the context of mechanobiology. Although a plausible explanation of surgical complications for immediate implant treatment is provided, extrapolation of results is only warranted by future systematic studies on more cadaver specimens and/or in vivo models. PMID:26162549

  11. 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.

  12. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...false Backing and facing for an artificial tooth. 872.3910 Section 872...3910 Backing and facing for an artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device...

  13. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Backing and facing for an artificial tooth. 872.3910 Section 872...3910 Backing and facing for an artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device...

  14. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Backing and facing for an artificial tooth. 872.3910 Section 872...3910 Backing and facing for an artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device...

  15. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Backing and facing for an artificial tooth. 872.3910 Section 872...3910 Backing and facing for an artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device...

  16. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Backing and facing for an artificial tooth. 872.3910 Section 872...3910 Backing and facing for an artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device...

  17. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  18. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  19. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  20. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  1. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  2. 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/?-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

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

    PubMed Central

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

    2010-01-01

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

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

    PubMed

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

    2013-01-01

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

  5. Optimize design dexterity of tooth-arrangement three-fingered hands

    NASA Astrophysics Data System (ADS)

    Wang, Hai-ying; Zhang, Li-yong; Zhang, Yong-de

    2005-12-01

    "Tooth-arrangement Three-fingered Hands" is a brand-new oral cavity repairing robot. It has the functions of fine grasping and arranging artificial tooth, manufacturing complete denture, etc. A new optimization design method is proposed in this paper that solves the problems in optimization structure parameter confirming and optimal dexterous design. The bionic theorem behind duplicating the dexterity of the human finger is incorporated into the structure parameter optimization algorithm. Through analyzing the dexterity of the single finger, adopting the design criteria of dexterous degree with optimum index and combining the characteristic of grasping the smallest object, this design method can confirm the best dexterity area for single finger, relations between every rod length and rotation range of every joint. Using MATLAB optimization toolbox to optimize above-mentioned structure parameter, it gains the optimal dimension that meets characteristic of human fingers and can finish grasping. A quantitative method is also proposed in this paper to calculate the relative position between fingers. It is applied to the real design of Tooth-Arrangement Three-fingered Hands and obtained optimal flexible performance.

  6. A 22-year follow-up of an endodontic implant.

    PubMed

    Wolff, Jan; Sándor, George K; Forouzanfar, Tim; Schulten, Engelbert A J M; Oikarinen, Kyösti S

    2015-10-01

    Root fractures in the middle and apical thirds of the root are treated by repositioning and for approximately 6 weeks of immobilization while those in the cervical third are immobilized for 3 months. Even though the results are good, some root-fractured teeth are lost and replaced by dental implants or fixed partial dentures. One historic but effective treatment option for those root fractures with unfavorable crown to root ratios is an endodontic implant in middle and apical third root fractures. This method offers immediate stable fixation of a crown and its coronal root segment to the underlying alveolar bone. This report documents the long-term survival of a tooth treated with an endodontic implant. A 25-year-old male patient presented following a bicycle accident with a dislocated unfavorable root fracture in the middle third. The crown with the coronal root segment was secured to the bone using a commercially available endodontic implant. The apical part of the root was removed. Although the clinical and radiological follow-up results of the endodontic implant demonstrated a good clinical function and little bone loss, the implant ultimately had to be removed after 22 years of service due to pain and increasing mobility. PMID:25865147

  7. Tooth staining effects of an alexidine mouthwash.

    PubMed

    Formicola, A J; Deasy, M J; Johnson, D H; Howe, E E

    1979-04-01

    The primary purpose of this study was to determine the amount of tooth staining produced by an alexidine mouthrinse. One hundred and eighty subjects rinsed twice daily for 1 month with either 15 ml of alexidine (0.035%) or a placebo solution. Prior to the study, the subjects were classified according to their smoking, coffee and tea drinking habits and these factors were subsequently considered in the analysis of the stain scores. Additionally, the effects on staining of a prior prophylaxis and the use of a fluoridated toothpaste during the study were determined. Upon termination of the study, subjects utilizing the active mouthrinse manifested a greater degree of staining than placebo users. The amount and intensity of the stain due to alexidine were not influenced (increased) by smoking, tea or coffee drinking habits. A prior prophylaxis did not reduce the staining propensity of alexidine users. The method of scoring developed can be used to assess the degree of tooth staining induced by antiplaque agents. PMID:374706

  8. 21 CFR 872.3200 - Resin tooth bonding agent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Resin tooth bonding agent. 872.3200 Section 872.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a)...

  9. 3D Simulation Modeling of the Tooth Wear Process

    PubMed Central

    Dai, Ning; Hu, Jian; Liu, Hao

    2015-01-01

    Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function) implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation. PMID:26241942

  10. On the Gap-Tooth direct simulation Monte Carlo method

    E-print Network

    Armour, Jessica D

    2012-01-01

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

  11. An Analysis of the Symptomatic Domains Most Relevant to Charcot Marie Tooth Neuropathy (CMT) Patients

    ClinicalTrials.gov

    2015-04-28

    Charcot Marie Tooth Disease (CMT); Hereditary Sensory and Motor Neuropathy; Nerve Compression Syndromes; Tooth Diseases; Congenital Abnormalities; Genetic Diseases, Inborn; Heredodegenerative Disorders, Nervous System

  12. Surgical Methods for the Acceleration of the Orthodontic Tooth Movement.

    PubMed

    Almpani, Konstantinia; Kantarci, Alpdogan

    2015-01-01

    Surgical techniques for the acceleration of the orthodontic tooth movement have been tested for more than 100 years in clinical practice. Since original methods have been extremely invasive and have been associated with increased tooth morbidity and various other gaps, the research in this field has always followed an episodic trend. Modern approaches represent a well-refined strategy where the concept of the bony block has been abandoned and only a cortical plate around the orthodontic tooth movement has been desired. Selective alveolar decortication has been a reproducible gold standard to this end. Its proposed mechanism has been the induction of rapid orthodontic tooth movement through the involvement of the periodontal ligament. More recent techniques included further refinement of this procedure through less invasive techniques such as the use of piezoelectricity and corticision. This chapter focuses on the evolution of the surgical approaches and the mechanistic concepts underlying the biological process during the surgically accelerated orthodontic tooth movement. PMID:26599122

  13. Cracked tooth syndrome: A report of three cases

    PubMed Central

    Sadasiva, Kadandale; Ramalingam, Sathishmuthukumar; Rajaram, Krishnaraj; Meiyappan, Alagappan

    2015-01-01

    Cracked tooth syndrome (CTS), the term was coined by Cameron in 1964, which refers to an incomplete fracture of a vital posterior tooth extending to the dentin and occasionally into the pulp. CTS has always been a nightmare to the patient because of its unpredictable symptoms and a diagnostic dilemma for the dental practitioner due to its variable, bizarre clinical presentation. The treatment planning and management of CTS has also given problems and challenges the dentist as there is no specific treatment option. The management of CTS varies from one case to another or from one tooth to another in the same individual based on the severity of the symptoms and depth of tooth structure involved. After all, the prognosis of such tooth is still questionable and requires continuous evaluation. This article aims at presenting a series three cases of CTS with an overview on the clinical presentation, diagnosis and the different treatment options that varies from one case to another. PMID:26538947

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

    PubMed Central

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

    1975-01-01

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

  15. Pacemakers and Implantable Defibrillators

    MedlinePLUS

    ... a cardiac pacemaker or an implantable cardioverter defibrillator (ICD). They are devices that are implanted in your ... and coordinate the chambers of the heart. An ICD monitors heart rhythms. If it senses dangerous rhythms, ...

  16. Implantable Medical Devices

    MedlinePLUS

    ... High Blood Pressure Tools & Resources Stroke More Implantable Medical Devices Updated:Sep 15,2015 For Rhythm Control ... Lifestyle Changes Recovery FAQs Medications Surgical Procedures Implantable Medical Devices Healthy Heart Quizzes • Heart Attack Tools & Resources ...

  17. Acceptor ion-implantation in SiC

    NASA Astrophysics Data System (ADS)

    Handy, Evan M.; Rao, Mulpuri V.; Holland, O. W.; Jones, K. A.; Chi, P. H.

    2000-05-01

    Single and multiple energy Al, B and Ga ion-implantations were performed into n-type 6H-SiC epitaxial layers. Empirical formulae for the range statistics of the implant depth distributions in the energy range 50 keV-4 MeV were developed by analyzing the experimental secondary ion mass spectrometry (SIMS) implant depth profiles. The Al and Ga implants were electrically activated at an annealing temperature of 1500°C, but the B implants required an annealing temperature of 1650°C. In this study annealings were performed by using AlN or graphite encapsulant. The Al and Ga implants are thermally stable but the B implants showed redistribution during annealing.

  18. Comparisons of a proposed five-seed assay method with the single-seed and batch assay methods for I-125 seeds in ultrasound-guided prostate implants.

    PubMed

    Lee, P C; Starr, S J; Zuhlke, K; Moran, B J

    1999-01-01

    A simple five-seed assay method was proposed and investigated. A commercial well ion chamber system with an NIST-traceable single-seed calibration constant was used for the single-seed assays. A batch seed holder was used for batch assays. For the five-seed assays, a second single-seed holder was modified such that all five seeds were loaded in a central region of the well ion chamber. Compared with the same seed in the standard single-seed holder, the relative chamber responses for the five seed positions were 0.993, 0.993, 1.000, 1.001, and 0.977, respectively, indicating little or no position-dependent chamber response and no self-attenuation among seeds. Subsequent comparison of assays with the single-seed and five-seed methods indicated only 0.4% difference in charge collection. The five-seed calibration constant was therefore taken to be the same as the single-seed calibration constant. The reproducibility of the five-seed assay method was found to be better than 0.8%. When a dummy seed replaced an active seed, a nearly 20% reduction in charge was found, indicating that the proposed five-seed assay method can detect a dead seed. Clinical comparison of all three assay methods showed that they produced qualitatively the same assay results when the batch assay method was performed with extra care. Compared with the single-seed assay method, the five-seed method is equally simple, rigid, and reproducible, but it demands much less assay time. Compared with the batch assay method, the five-seed method is much more reproducible and reliable because of its rigid assay geometry; it only demands a moderate amount of assay time and can detect dead seeds. The American Association of Physicists in Medicine Task Group 40 (AAPM TG40) states that, for brachytherapy, ideally every (i.e., 100%) loose seed should be calibrated. For procedures involving large number of loose seeds, it then recommends that 10% of seeds be calibrated. The proposed five-seed assay is very simple to implement. It will facilitate the compliance of the "10%" recommendation from the AAPM TG40; it will make the "ideally 100%" statement from AAPM TG40 a more realistic and practical QA procedure in seed assaying. PMID:10644061

  19. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1984-01-01

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

  20. Cochlear Implants for Children.

    ERIC Educational Resources Information Center

    Hasenstab, M. Suzanne; Laughton, Joan

    1991-01-01

    The use of cochlear implants in children with profound bilateral hearing loss is discussed, focusing on how a cochlear implant works; steps in a cochlear implant program (evaluation, surgery, programing, and training); and rehabilitation procedures involved in auditory development and speech development. (JDD)

  1. Knowledge and attitudes of dental interns in Karnataka state, India, regarding implants.

    PubMed

    Chaudhary, Sohini; Gowda, Triveni M; Kumar, Tarun A B; Mehta, Dhoom S

    2013-10-01

    Implant treatment today is highly reliable as a valid restorative option for missing teeth. As more patients worldwide opt for implant treatment, it is now imperative for dental practitioners to have sound information about dental implants so they can help patients make informed decisions. This study sought to define the knowledge and attitudes regarding dental implants of dental interns in the state of Karnataka, India, and to evaluate the dental implant curriculum structure at the undergraduate level. A survey was conducted of dental interns (students in their fifth, clinical year of undergraduate study) in seven of the forty-five academic dental institutions in this state. The questionnaire consisted of fifteen questions that assessed the respondents' level of knowledge and source of information regarding implants. A total of 500 questionnaires were distributed, and 417 interns responded for a response rate of 83.4 percent. In the results, 73.3 percent reported they were not provided sufficient information about implants in their undergraduate curriculum, and 95.7 percent of them wanted more. Also, 63.5 percent of the respondents believed that high costs could limit the use of dental implants as a tooth replacement modality in India. This study concludes that revision in the undergraduate dental curricula at these schools is needed to better prepare students for practicing implant dentistry. PMID:24098041

  2. Strontium coating by electrochemical deposition improves implant osseointegration in osteopenic models.

    PubMed

    Liang, Yongqiang; Li, Haoyan; Xu, Jiang; Li, Xin; Li, Xinchang; Yan, Yuting; Qi, Mengchun; Hu, Min

    2015-01-01

    Osteopenia, a preclinical state of osteoporosis, restricts the application of adult orthodontic implant anchorage and tooth implantation. Strontium (Sr) is able to promote bone formation and inhibit bone absorption. The aim of the present study was to evaluate a new method for improving the success rate of dental implantation. In this study, an electrochemical deposition (ECD) method was used to prepare a Sr coating on a titanium implant. The coating composition was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction, and the surface morphology of the coating was studied using scanning electron microscopy. A total of 24 Sprague-Dawley rats received bilateral ovariectomy (OVX) and an additional 12 rats underwent a sham surgery. All rats were then implanted in the bilateral tibiae with titanium mini-implants with or without a Sr coating. The results of histological examination and a fluorescence double labeling assay showed strong new bone formation with a wider zone between the double labels, a higher rate of bone mineralization and better osseointegration in the OVX rats that received Sr-coated implants compared with the OVX rats that received uncoated implants. The study indicates that Sr coatings are easily applied by an ECD method, and that Sr coatings have a promoting effect on implant osseointegration in animals with osteopenia. PMID:25452797

  3. Tooth Size Variation in Pinniped Dentitions

    PubMed Central

    Wolsan, Mieczyslaw; Suzuki, Satoshi; Asahara, Masakazu; Motokawa, Masaharu

    2015-01-01

    It is contentious whether size variation among mammalian teeth is heterogeneous or homogeneous, whether the coefficient of variation is reliable, and whether the standard deviation of log-transformed data and the residual of standard deviation on mean variable size are useful replacements for the coefficient of variation. Most studies of tooth size variation have been on mammals with complex-crowned teeth, with relatively little attention paid to taxa with simple-crowned teeth, such as Pinnipedia. To fill this gap in knowledge and to resolve the existing controversies, we explored the variation of linear size variables (length and width) for all teeth from complete permanent dentitions of four pinniped species, two phocids (Histriophoca fasciata, Phoca largha) and two otariids (Callorhinus ursinus, Eumetopias jubatus). Size variation among these teeth was mostly heterogeneous both along the toothrow and among species. The incisors, canines, and mesial and distal postcanines were often relatively highly variable. The levels of overall dental size variation ranged from relatively low as in land carnivorans (Phoca largha and both otariids) to high (Histriophoca fasciata). Sexual size dimorphism varied among teeth and among species, with teeth being, on average, larger in males than in females. This dimorphism was more pronounced, and the canines were larger and more dimorphic relative to other teeth in the otariids than in the phocids. The coefficient of variation quantified variation reliably in most cases. The standard deviation of log-transformed data was redundant with the coefficient of variation. The residual of standard deviation on mean variable size was inaccurate when size variation was considerably heterogeneous among the compared variables, and was incomparable between species and between sexes. The existing hypotheses invoking developmental fields, occlusal complexity, and the relative timing of tooth formation and sexually dimorphic hormonal activity do not adequately explain the differential size variation along the pinniped toothrow. PMID:26317362

  4. Tooth loss is associated with increased risk of esophageal cancer: evidence from a meta-analysis with dose-response analysis.

    PubMed

    Chen, Qi-Lin; Zeng, Xian-Tao; Luo, Zhi-Xiao; Duan, Xiao-Li; Qin, Jie; Leng, Wei-Dong

    2016-01-01

    Epidemiological studies have revealed the association between tooth loss and the risk of esophageal cancer (EC); however, consistent results were not obtained from different single studies. Therefore, we conducted the present meta-analysis to evaluate the association between tooth loss and EC. We conducted electronic searches of PubMed until to February 10, 2015 to identify relevant observational studies that examined the association between tooth loss and the risk of EC. Study selection and data extraction from eligible studies were independently performed by two authors. The meta-analysis was conducted using Stata 12.0 software. Finally eight eligible publications with ten studies involving 3 cohort studies, 5 case-control studies, and 1 cross-sectional study were yielded. Meta-analysis identified tooth loss increased risk of EC 1.30 times (Relative risk?=?1.30, 95% confidence interval?=?1.06-1.60, I(2)?=?13.5%). Dose-response analysis showed linear relationship between tooth loss and risk of EC (RR?=?1.01, 95%CI?=?1.00-1.03; P for non-linearity test was 0.45). Subgroup analysis proved similar results and publication bias was not detected. In conclusion, tooth loss could be considered to be a significant and dependent risk factor for EC based on the current evidence. PMID:26742493

  5. Modified Titanium Implant as a Gateway to the Human Body: The Implant Mediated Drug Delivery System

    PubMed Central

    Park, Young-Seok; Cho, Joo-Youn; Hwang, Chee Il

    2014-01-01

    The aim of this study was to investigate the efficacy of a proposed new implant mediated drug delivery system (IMDDS) in rabbits. The drug delivery system is applied through a modified titanium implant that is configured to be implanted into bone. The implant is hollow and has multiple microholes that can continuously deliver therapeutic agents into the systematic body. To examine the efficacy and feasibility of the IMDDS, we investigated the pharmacokinetic behavior of dexamethasone in plasma after a single dose was delivered via the modified implant placed in the rabbit tibia. After measuring the plasma concentration, the areas under the curve showed that the IMDDS provided a sustained release for a relatively long period. The result suggests that the IMDDS can deliver a sustained release of certain drug components with a high bioavailability. Accordingly, the IMDDS may provide the basis for a novel approach to treating patients with chronic diseases. PMID:25136624

  6. Natal tooth associated with fibrous hyperplasia - a rare case report.

    PubMed

    Sethi, Harsimran Singh; Munjal, Deepti; Dhingra, Renuka; Malik, Narender Singh; Sidhu, Gagandeep Kaur

    2015-04-01

    Eruption of tooth at about 6 months of age is a significant stage in child's life and is an emotional event for parents. However, a tooth present in the oral cavity of newborn can lead to a lot of delusions. Natal and neonatal teeth are of utmost importance not only for a dentist but also for a paediatrician due to parent's anxiety, folklore superstitions and numerous associated complications with it. This paper reports a rare case, wherein a natal tooth has led to the development of a reactive fibrous hyperplasia in an 8-week-old infant. PMID:26023656

  7. Insight: implantable medical devices.

    PubMed

    Meng, E; Sheybani, R

    2014-09-01

    Implantable electronic medical devices have achieved remarkable medical advances in the treatment of the most challenging conditions, starting with the introduction of the first implantable pacemaker in 1958. Increasing demand for innovation in existing and novel implantable devices is fuelled by the growing aging population and the increased prevalence of chronic diseases. This perspective article provides an overview of the implantable medical device ecosystem, highlights recent developments, and discusses challenges and opportunities for translation of new innovative implants enabled by microtechnologies and microfabrication. PMID:24903337

  8. Irregular tooth spacing reduces roller cone bit tracking problems

    SciTech Connect

    Kenner, J.V.; Boylan, T.P.

    1996-05-13

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

  9. Irregular tooth spacing reduces tracking of roller cone bits

    SciTech Connect

    Kenner, J.V.; Boylan, T.P.

    1996-09-01

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

  10. Accuracy of 3D scanners in tooth mark analysis.

    PubMed

    Molina, Ana; Martin-de-las-Heras, Stella

    2015-01-01

    The objective of this study was to compare the accuracy of contact and laser 3D scanners in tooth mark analysis. Ten dental casts were scanned with both 3D scanners. Seven linear measurements were made from the 3D images of dental casts and biting edges generated with DentalPrint© software (University of Granada, Granada, Spain). The uncertainty value for contact 3D scanning was 0.833 for the upper dental cast and 0.660 mm for the lower cast; similar uncertainty values were found for 3D-laser scanning. Slightly higher uncertainty values were obtained for the 3D biting edges generated. The uncertainty values for single measurements ranged from 0.1 to 0.3 mm with the exception of the intercanine distance, in which higher values were obtained. Knowledge of the error rate in the 3D scanning of dental casts and biting edges is especially relevant to be applied in practical forensic cases. PMID:25388960

  11. Trends in Cochlear Implants

    PubMed Central

    Zeng, Fan-Gang

    2004-01-01

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

  12. Study of the kinematic and load sharing properties of wormgearing with non-symmetric tooth profiles

    NASA Technical Reports Server (NTRS)

    Sun, D. C.; Yuan, Qin

    1995-01-01

    The geometry of non-symmetric tooth profiles, i.e. tooth profiles with different pressure angles on the two sides of the tooth, is studied. A feasible non-symmetric tooth profile for application in helicopter transmissions is laid out as the best compromise among several conflicting factors. The non-symmetric tooth profile is then compared with the symmetric tooth profile studied previously. Based on the detailed comparisons it is concluded that the use of the non-symmetric tooth profile would severely limit the face width of the worm, consequently reduce the number of meshing teeth and cause much higher normal load on the individual gear teeth.

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

    SciTech Connect

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

    2009-02-09

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

  14. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture...

  15. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture...

  16. 21 CFR 872.3590 - Preformed plastic denture tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture...

  17. Two mathematical models for generation of crowned tooth surface.

    PubMed

    Kelemen, Laszlo; Szente, Jozsef

    2014-01-01

    Gear couplings are mechanical components to connect shaft ends and eliminate the misalignments. The most important element of the gear coupling is the hub which is an external gear having crowned teeth. The crowned teeth on the hub are typically produced by hobbing. The resulting tooth surface depends on several parameters. It is influenced by the size of the hob and the feed. In this paper two mathematical models of the crowned tooth surface are introduced for the generation of the idealized tooth surfaces. These are the profile-shifting and the two-parameter enveloping methods. Our aim is to compare the obtained crowned tooth profiles for the two examined models and to investigate the results. From our numerical results, it was found that the two profiles show indistinguishable differences. PMID:24578653

  18. [Nasal cavity supernumerary tooth and maxillary sinusitis: one case reported].

    PubMed

    Guo, Guangliang; Hu, Limin; Lu, Yuan

    2015-08-01

    Supernumerary tooth is a rare case. This report described a case of nasal cavity supernumerary tooth association with maxillary sinusitis. A 28-year-old male patient reported with the chief complaint of nasal obstruction, headache and purulent secretion for the past three months. Clinic examination and CT examination showed that there was a supernumerary tooth in the right nasal bottom, and maxillary sinus was infected in the same side. This patient was performed supernumerary tooth removing and given antibiotics for 3 days. Ten days after the operation, there was no clinical symptoms, and nasal bottom mucosa was normal. After 3 months of follow-up, reexamination of coronal CT scan appeared normal. PMID:26665468

  19. Drugs influencing orthodontic tooth movement: An overall review

    PubMed Central

    Diravidamani, Kamatchi; Sivalingam, Sathesh Kumar; Agarwal, Vivek

    2012-01-01

    Orthodontic treatment is based on the premise that when force is delivered to a tooth and thereby transmitted to the adjacent investing tissues, certain mechanical, chemical, and cellular events take place within these tissues, which allow for structural alterations and contribute to the movement of that tooth. Molecules present in drugs and nutrients consumed regularly by patients can reach the mechanically stressed paradental tissues through the circulation and interact with local target cells. The combined effect of mechanical forces and one or more of these agents may be inhibitory, additive, or synergistic. Current orthodontic research aims to develop methods of increasing the tissue concentration of molecules promoting tooth movement, while simultaneously decreasing the concentration of unwanted elements which can produce harmful side effects. This article discusses in detail the various possible drugs that can bring about alterations in the desired orthodontic tooth movement. PMID:23066275

  20. Two Mathematical Models for Generation of Crowned Tooth Surface

    PubMed Central

    Kelemen, Laszlo; Szente, Jozsef

    2014-01-01

    Gear couplings are mechanical components to connect shaft ends and eliminate the misalignments. The most important element of the gear coupling is the hub which is an external gear having crowned teeth. The crowned teeth on the hub are typically produced by hobbing. The resulting tooth surface depends on several parameters. It is influenced by the size of the hob and the feed. In this paper two mathematical models of the crowned tooth surface are introduced for the generation of the idealized tooth surfaces. These are the profile-shifting and the two-parameter enveloping methods. Our aim is to compare the obtained crowned tooth profiles for the two examined models and to investigate the results. From our numerical results, it was found that the two profiles show indistinguishable differences. PMID:24578653

  1. Complications associated with cheek tooth extraction in the horse.

    PubMed

    Earley, Edward T; Rawlinson, Jennifer E; Baratt, Robert M

    2013-01-01

    Common indications for cheek tooth extraction in the horse include dental fracture, periodontal disease, severe decay/ caries, mandibular fracture with alveolar/tooth involvement, and periapical abscess. Complications secondary to extraction of cheek teeth are prevalent. Typical complications may include retained root tip(s), collateral damage of neighboring teeth and alveolar bone, mandibular fracture non-union or delayed union, cemental ankylosis, dilacerated root(s), oroantral/oronasal fistula, palatal deviation of cheek teeth, bone sequestration, sinus involvement, alveolar plug failure, and palatine artery laceration. This paper presents a series of cases that had complications following cheek tooth extraction. Anticipation of problematic extractions, recognition of complications, and appropriate treatment will aid the clinician in managing the inevitable cheek tooth extraction complication. PMID:24660307

  2. Measurement for natural dental neck data of normal adults and its clinical significance on guiding implant restoration

    PubMed Central

    Sun, Mingxu; Gu, Fang; Wang, Junjun; Zhou, Chengyuan; Xia, Junnan; Qin, Hongwei; Yang, Jianjun

    2015-01-01

    Objective: Provide reference basis for the clinical implant restoration to select implant diameter through measuring each data of 7 teeth in the dental neck of bilateral upper and lower jaws of the young volunteers with normal dentition. Methods: Select 30 healthy young volunteers with complete dentition but no malocclusion, take cone beam CT (CBCT), measure the mesiodistal and buccolingual distance of the tooth root at 1.5 mm from 14 teeth (bilateral upper and lower jaws) to alveolar crest, trace out the outline of each tooth neck in this layer, calculate the cross sectional area and roundness of each tooth neck according to pixel value calibration, and then carry out statistical processing. Results: Complete the data collection and processing of mesiodistal length, buccolingual width, cross sectional area, and cross sectional roundness of the dental neck at 1.5 mm from these seven teeth of the bilateral upper and lower jaws to the alveolar crest of 30 volunteers, and calculate the mean value, variance, and reference value range of medical science of each index. Conclusion: CBCT can effectively obtain the image information of the dental neck. Through mimics 10.0 and Photoshop CS3, it is possible to accurately calculate the dental neck length and width, and cross sectional area of each tooth according to CBCT image information. This result can provide reference basis for the implant restoration of the clinical teeth. PMID:26628955

  3. 3D-Geomorphometrics tooth shape analysis in hypodontia

    PubMed Central

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

    2014-01-01

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

  4. Assessment of Tooth Proportions in an Aesthetically Acceptable Smile

    PubMed Central

    Reddy, Munish; Raghav, Pradeep; Jain, Shalu; Anjum, Arbab; Misra, Vaibhav; Suri, Ragini

    2015-01-01

    Introduction: Aesthetic facial animation is mostly reported to be due to a close relationship between soft and hard tissue i.e. dynamic smile with appropriate tooth proportions. But variations in tooth size have been seen among various ethnic populations globally. Aim: To evaluate the size and morphology of maxillary anterior teeth, the tooth with maximum variation both mesiodistally and cervicoincisally. Also, the tooth to tooth ratio in percentage of the mean tooth sizes in both genders in patients with aesthetically acceptable smile decided by a panel in North Indian population. Materials and Methods: A total of 100 subjects (50 males and 50 females) were taken and a video clip of their dynamic smile was captured .The smiles were analyzed by a panel and the tooth proportions of the selected attractive smiles were evaluated in both males and females separately. Statistical analysis: Data obtained was subjected to statistical analysis using Microsoft Excel 2007 software; test used was Unpaired t-test and also Mean ± S.D., Variance, Ratio of W/L and its ranges were calculated. Significance is assessed at 5% level of significance. Results: The mesiodistal width and cervicoincisal length of maxillary central incisor was greater compared to lateral incisor and canine in both males and females. There was a statistically significant difference between the width/length ratio of maxillary anterior teeth between males and females.Canine and Lateral incisor showed maximum variation mesio-distally and cervico-incisally. Conclusion: A smile is more pleasing if the visible teeth are in proper morphological proportions. Thus, it relates that teeth play a vital role in increasing the attractiveness of a smile. The mean coronal width/length ratio displayed a more square like tooth form for both males and females. PMID:26023632

  5. 3D-Geomorphometrics tooth shape analysis in hypodontia.

    PubMed

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

    2014-01-01

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

  6. Method for implantation of high dopant concentrations in wide band gap materials

    DOEpatents

    Usov, Igor (Los Alamos, NM); Arendt, Paul N. (Los Alamos, NM)

    2009-09-15

    A method that combines alternate low/medium ion dose implantation with rapid thermal annealing at relatively low temperatures. At least one dopant is implanted in one of a single crystal and an epitaxial film of the wide band gap compound by a plurality of implantation cycles. The number of implantation cycles is sufficient to implant a predetermined concentration of the dopant in one of the single crystal and the epitaxial film. Each of the implantation cycles includes the steps of: implanting a portion of the predetermined concentration of the one dopant in one of the single crystal and the epitaxial film; annealing one of the single crystal and the epitaxial film and implanted portion at a predetermined temperature for a predetermined time to repair damage to one of the single crystal and the epitaxial film caused by implantation and activates the implanted dopant; and cooling the annealed single crystal and implanted portion to a temperature of less than about 100.degree. C. This combination produces high concentrations of dopants, while minimizing the defect concentration.

  7. Nanotechnology and Dental Implants

    PubMed Central

    Lavenus, Sandrine; Louarn, Guy; Layrolle, Pierre

    2010-01-01

    The long-term clinical success of dental implants is related to their early osseointegration. This paper reviews the different steps of the interactions between biological fluids, cells, tissues, and surfaces of implants. Immediately following implantation, implants are in contact with proteins and platelets from blood. The differentiation of mesenchymal stem cells will then condition the peri-implant tissue healing. Direct bone-to-implant contact is desired for a biomechanical anchoring of implants to bone rather than fibrous tissue encapsulation. Surfaces properties such as chemistry and roughness play a determinant role in these biological interactions. Physicochemical features in the nanometer range may ultimately control the adsorption of proteins as well as the adhesion and differentiation of cells. Nanotechnologies are increasingly used for surface modifications of dental implants. Another approach to enhance osseointegration is the application of thin calcium phosphate (CaP) coatings. Bioactive CaP nanocrystals deposited on titanium implants are resorbable and stimulate bone apposition and healing. Future nanometer-controlled surfaces may ultimately direct the nature of peri-implant tissues and improve their clinical success rate. PMID:21253543

  8. The saddle connective tissue graft: a periodontal plastic surgery technique to obtain soft tissue coronal gain on immediate implants. A case report.

    PubMed

    González, David; Cabello, Gustavo; Olmos, Gema; Niñoles, Carlos L

    2015-01-01

    Based on recent studies regarding the advantages of flapless immediate implants on the maintenance of the soft tissue architecture (especially at papillae level) in those situations where it is necessary to extract an anterior tooth, this case report describes a clinical procedure designed to replace a hopeless central incisor (2.1) showing root resorption adjacent to an implant-supported crown (1.1), whose gingival margin is 2 mm coronal regarding the hopeless tooth to be replaced. After the extraction of the hopeless tooth (2.1), a flapless immediate implant was placed. The implant-bone gap was then filled with bone substitute and a palatal connective tissue graft was placed ad modum saddle extending at buccal level from apical to the mucogingival line, sealing the socket and extending until 6 mm at palatal level ad modum saddle. This procedure allowed symmetry of the soft tissue margins between the two implants (1.1 and 2.1) to be obtained as well as the preservation of the inter-implant papillae (1.1). PMID:26171446

  9. Personalized Orthodontic Accurate Tooth Arrangement System with Complete Teeth Model.

    PubMed

    Cheng, Cheng; Cheng, Xiaosheng; Dai, Ning; Liu, Yi; Fan, Qilei; Hou, Yulin; Jiang, Xiaotong

    2015-09-01

    The accuracy, validity and lack of relation information between dental root and jaw in tooth arrangement are key problems in tooth arrangement technology. This paper aims to describe a newly developed virtual, personalized and accurate tooth arrangement system based on complete information about dental root and skull. Firstly, a feature constraint database of a 3D teeth model is established. Secondly, for computed simulation of tooth movement, the reference planes and lines are defined by the anatomical reference points. The matching mathematical model of teeth pattern and the principle of the specific pose transformation of rigid body are fully utilized. The relation of position between dental root and alveolar bone is considered during the design process. Finally, the relative pose relationships among various teeth are optimized using the object mover, and a personalized therapeutic schedule is formulated. Experimental results show that the virtual tooth arrangement system can arrange abnormal teeth very well and is sufficiently flexible. The relation of position between root and jaw is favorable. This newly developed system is characterized by high-speed processing and quantitative evaluation of the amount of 3D movement of an individual tooth. PMID:26208593

  10. Tooth wear: when to treat, why, and how. Part One.

    PubMed

    Larson, Thomas D

    2009-01-01

    Tooth wear has been described in the literature as physiologic--that is, normal, expected over the life span of an individual, and not creating a pathologic condition. It has also been described in pathologic terms as caused by stress, corrosion, and friction, utilizing a variety of mechanisms and affected by a host of endogenous and exogenous factors. From a clinician's point of view, when should we decide to restore a tooth or change the conditions in the mouth to protect the teeth; and what should we consider using to either prevent or restore abnormal--i.e., pathologic--tooth wear? This review in Part One will look at what is normal, non-pathologic tooth wear and etiologies associated with all forms of tooth wear. Part Two will discuss the effects of tooth wear in enamel and dentin, when it may be advisable to intervene in the wear processes diagnosed on specific patients, and what methods of prevention and restoration can be utilized to restore or maintain the dentition. This review will not look at the need for full mouth reconstruction due to wear. PMID:19927571

  11. Tooth wear: when to treat, why, and how. Part two.

    PubMed

    Larson, Thomas D

    2009-01-01

    Tooth wear has been described in the literature as physiologic--that is, normal, expected over the life span of an individual, and not creating a pathologic condition. It has also been described in pathologic terms as caused by stress, corrosion, and friction, utilizing a variety of mechanisms and affected by a host of endogenous and exogenous factors. From a clinician's point of view, when should we decide to restore a tooth or change the conditions in the mouth to protect the teeth; and what should we consider using to either prevent or restore abnormal--i.e, pathologic--tooth wear? This review in Part One (Northwest Dentistry, September-October 2009) looked at what is normal, non-pathologic tooth wear and etiologies associated with all forms of tooth wear. Part Two will discuss the effects of tooth wear in enamel and dentin, when it may be advisable to intervene in the wear processes diagnosed on specific patients, and what methods of prevention and restoration can be utilized to restore or maintain the dentition. This review will not look at the need for full mouth reconstruction due to wear. PMID:20120632

  12. 2D FEA of evaluation of micromovements and stresses at bone-implant interface in immediately loaded tapered implants in the posterior maxilla

    PubMed Central

    Desai, Shrikar R.; Singh, Rika; Karthikeyan, I.

    2013-01-01

    Aim: The aim of the study is to evaluate the influence implant length on stress distribution at bone implant interface in single immediately loaded implants when placed in D4 bone quality. Materials and Methods: A 2-dimensional finite element models were developed to simulate two types of implant designs, standard 3.75 mm–diameter tapered body implants of 6 and 10 mm lengths. The implants were placed in D4 bone quality with a cortical bone thickness of 0.5 mm. The implant design incorporated microthreads at the crestal part and the rest of the implant body incorporated Acme threads. The Acme thread form has a 29° thread angle with a thread height half of the pitch; the apex and valley are flat. A 100 N of force was applied vertically and in the oblique direction (at an angle of 45°) to the long axis of the implants. The respective material properties were assigned. Micro-movements and stresses at the bone implant interface were evaluated. Results: The results of total deformation (micro-movement) and Von mises stress were found to be lower for tapered long implant (10 mm) than short implant (6 mm) while using both vertical as well as oblique loading. Conclusion: Short implants can be successfully placed in poor bone quality under immediate loading protocol. The novel approach of the combination of microthreads at the crestal portion and acme threads for body portion of implant fixture gave promising results. PMID:24174759

  13. Effect of platelet-rich plasma and platelet-rich fibrin on peri-implant bone defects in dogs.

    PubMed

    Jeong, Kyung-In; Kim, Su-Gwan; Oh, Ji-Su; Lee, Sung-Yong; Cho, Young-Seung; Yang, Sung-Soo; Park, Seung-Cheol; You, Jae-Seek; Lim, Sung-Chul; Jeong, Mi-Ae; Kim, Jae-Sung; Lee, Sook-Young

    2013-03-01

    The purpose of this study was to evaluate the effect of tooth ash and platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) grafts into bone defects around implants on bone formation. Six adult dogs were used as experimental subjects. Graft materials were used to create a particulate material. Forty-eight tapered-type implants, 3.7 mm in diameter, 10 mm in length, and with surface treated with hydroxyapatite (HA) coating, were used as implant fixtures. Using a trephine bur, four bone defects were formed and implants were placed in the femurs of the adult dogs. Bone grafts were not performed in the control group. Tooth ash was grafted into the defects in group 1. In group 2, a mixture of tooth ash and PRP (1:1 ratio by volume) was grafted into the defects. In group 3, a mixture of tooth ash and PRF (ratio of 1:1) was grafted in the defect area. Animals were sacrificed after 4 or 8 weeks. Based on histopathological examination, the amount and rate of new bone formation were evaluated. Histomorphometric examination revealed that the rate of new bone formation in group 3 of the 4-week group was significantly higher than that in the control group. In addition, in the 8-week group, a significant increase in new bone formation was confirmed in group 3. In this study, a bone graft method using a mixture of tooth ash and PRF was found to increase new bone formation compared to the method using PRP. In addition, it was confirmed that this effect was more prominent in the initial stage of the bone graft. PMID:23621011

  14. Intermediate Charcot-Marie-Tooth disease.

    PubMed

    Liu, Lei; Zhang, Ruxu

    2014-12-01

    Charcot-Marie-Tooth (CMT) disease is a common neurogenetic disorder and its heterogeneity is a challenge for genetic diagnostics. The genetic diagnostic procedures for a CMT patient can be explored according to the electrophysiological criteria: very slow motor nerve conduction velocity (MNCV) (<15 m/s), slow MNCV (15-25 m/s), intermediate MNCV (25-45 m/s), and normal MNCV (>45 m/s). Based on the inheritance pattern, intermediate CMT can be divided into dominant (DI-CMT) and recessive types (RI-CMT). GJB1 is currently considered to be associated with X-linked DI-CMT, and MPZ, INF2, DNM2, YARS, GNB4, NEFL, and MFN2 are associated with autosomal DI-CMT. Moreover, GDAP1, KARS, and PLEKHG5 are associated with RI-CMT. Identification of these genes is not only important for patients and families but also provides new information about pathogenesis. It is hoped that this review will lead to a better understanding of intermediate CMT and provide a detailed diagnostic procedure for intermediate CMT. PMID:25326399

  15. Tooth-surface-specific Effects of Xylitol

    PubMed Central

    Ritter, A.V.; Bader, J.D.; Leo, M.C.; Preisser, J.S.; Shugars, D.A.; Vollmer, W.M.; Amaechi, B.T.; Holland, J.C.

    2013-01-01

    The Xylitol for Adult Caries Trial was a three-year, double-blind, multi-center, randomized clinical trial that evaluated the effectiveness of xylitol vs. placebo lozenges in the prevention of dental caries in caries-active adults. The purpose of this secondary analysis was to investigate whether xylitol lozenges had a differential effect on cumulative caries increments on different tooth surfaces. Participants (ages 21-80 yrs) with at least one follow-up visit (n = 620) were examined at baseline, 12, 24, and 33 months. Negative binomial and zero-inflated negative binomial regression models were used to estimate incidence rate ratios (IRR) for xylitol’s differential effect on cumulative caries increments on root and coronal surfaces and, among coronal surfaces, on smooth (buccal and lingual), occlusal, and proximal surfaces. Participants in the xylitol arm developed 40% fewer root caries lesions (0.23 D2FS/year) than those in the placebo arm (0.38 D2FS/year; IRR = 0.60; 95% CI [0.44, 0.81]; p < .001). There was no statistically significant difference between xylitol and control participants in the incidence of smooth-surface caries (p = .100), occlusal-surface caries (p = .408), or proximal-surface caries (p = .159). Among these caries-active adults, xylitol appears to have a caries-preventive effect on root surfaces (ClinicalTrials.gov NCT00393055). PMID:23589387

  16. Studies on Bilateral Cochlear Implants at the University of Wisconsin's Binaural Hearing

    E-print Network

    Litovsky, Ruth

    Studies on Bilateral Cochlear Implants at the University of Wisconsin's Binaural Hearing and Speech with a single cochlear implant (CI), focusing on measures of spatial hearing and speech understanding in noise rehabilitation, cochlear implants, diagnostic techniques, hearing science, speech perception Abbreviations: BHSL

  17. Anti Cariogenic Efficacy of Herbal and Conventional Tooth Pastes - A Comparative In-Vitro Study

    PubMed Central

    K P, Mohankumar; N K, Priya; G S, Madhushankari

    2013-01-01

    Background: An upsurge of herbal products in various catalogues of fast moving consumer goods is evident. Dental creams or pastes which have numerous brands since years, have addition of many more herbal tooth pastes. Main claim of these herbal tooth pastes being effective reduction in cavities and plaque control. Proven fact is that proper brushing with a tooth brush and tooth paste brings down the caries incidence, and there is a substantial amount of contribution made by indispensable ingredient i.e, tooth pastes and their antibacterial component. Aim: To evaluate the antibacterial efficacy of various herbal tooth pastes available in the market and compare it with a conventional tooth paste with known antibacterial effect. Materials & Methods: The antibacterial efficacy of five herbal tooth pastes and two conventional tooth pastes with different ingredients was evaluated by the zone of inhibition created around the disc on the culture plates against streptococcus mutans and lactobacillus acidophilus. Results: The herbal tooth pastes showed similar efficacy as that of the conventional tooth pastes. One herbal tooth paste with multiple herbal ingredients had greater zone of inhibition compared to the conventional tooth pastes and other herbal tooth pastes. Conclusion: Herbal tooth pastes have similar antibacterial effect as conventional tooth pastes. Tooth paste with multiple herbal ingredients is more efficient than the tooth pastes with fewer herbal ingredients in an anticariogenic property. How to cite this article: Mohan Kumar K P, Priya N K, Madhushankari G S. Anti Cariogenic Efficacy of Herbal and Conventional Tooth Pastes - A Comparative In-Vitro Study. J Int Oral Health 2013; 5(2):8-13. PMID:24155585

  18. Does Timing of Eruption in First Primary Tooth Correlate with that of First Permanent Tooth? A 9-years Cohort Study

    PubMed Central

    Poureslami, Hamidreza; Asl Aminabadi, Naser; Sighari Deljavan, Alireza; Erfanparast, Leila; Sohrabi, Azin; Jamali, Zahra; Ghertasi Oskouei, Sina; Hazem, Kameliya; Shirazi, Sajjad

    2015-01-01

    Background and aims. Predicting the teeth eruption time is a valuable tool in pediatric dentistry since it can affects scheduling dental and orthodontic treatments. This study investigated the relationship between the eruption time of first primary and permanent teeth and the variation in the eruption time considering socioeconomic status (SES) in a 9-year population- based cohort study. Materials and methods. 307 subjects were examined at bimonthly intervals during the first and second years of life and then at six-month intervals until the eruption of first permanent tooth. Eruption times of primary and permanent tooth were recorded for each child. A modified form of Kuppuswamy’s scale was used to assess the SES. Results. Among 267 subjects completed all follow-ups, the eruption time for first primary and permanent teeth indicated a direct strong correlation; in that one month delayed or early eruption of firstprimary tooth resulted in 4.21 months delayed or early eruption of first appearing permanent tooth (r = 0.91, n = 267, P <0.001). No significant correlation was observed between the eruption time of first primary and first permanent teeth and SES (P = 0.67, P = 0.75, respectively). Conclusion. The eruption timing for the first primary tooth had a correlation with the first permanent tooth eruption tim-ing, while SES did not have any influence on eruption times. PMID:26236432

  19. [The artificial lens implant].

    PubMed

    Cârstocea, B; Selaru, D; Filip, M; Sandu, E; Stefan, C; Isp??oiu, C; Banaeu, I

    1993-01-01

    The paper presents a short history of the cataract intervention, starting from the lens luxation in vitreum and going to the implant of artificial lens. From the three classes of artificial lenses, up-to-date options are the posterior chamber artificial lenses. Today, in 80% of the cases, artificial lens implant is done, 80% of the implanted lenses being posterior chamber lenses. The paper also exposes various operatorial techniques, post-operatorial evolution and the results obtained. PMID:8507623

  20. [Silastic implant and synovitis].

    PubMed

    Sennwald, G

    1989-07-22

    The silastic implant based on siloxane polymere induces granulomatous synovitis in certain predisposed individuals, a reaction which may continue even after removal of the implant. This is also true of a prosthesis of the trapezium in two of our patients, though to a lesser degree. This is probably the reason why the problem has not yet been widely recognized. The hypothesis is put forward that an enzymatic predisposition may allow chemical degradation of the fragmented silastic implant into a toxic component responsible for the pathologic condition. The slow progression of the lesions is a challenge for the future and puts in question the further use of silastic implants. PMID:2678435

  1. Effects of ion-releasing tooth-coating material on demineralization of bovine tooth enamel.

    PubMed

    Kawasaki, Koji; Kambara, Masaki

    2014-01-01

    We compared the effect of a novel ion-releasing tooth-coating material that contained S-PRG (surface-reaction type prereacted glass-ionomer) filler to that of non-S-PRG filler and nail varnish on the demineralization of bovine enamel subsurface lesions. The demineralization process of bovine enamel was examined using quantitative light-induced fluorescence (QLF) and electron probe microanalyzer (EPMA) measurement. Ion concentrations in demineralizing solution were measured using inductively coupled plasma atomic (ICP) emission spectrometry and an ion electrode. The nail varnish group and the non-S-PRG filler group showed linear demineralization. Although the nail varnish group and the non-S-PRG filler group showed linear demineralization, the S-PRG filler group did not. Further, plane-scanning by EPMA analysis in the S-PRG filler group showed no changes in Ca ion distribution, and F ions showed peak levels on the surface of enamel specimens. Most ions in the demineralizing solution were present at higher concentrations in the S-PRG filler group than in the other two groups. In conclusion, only the S-PRG filler-containing tooth-coating material released ions and inhibited demineralization around the coating. PMID:24578706

  2. Effects of Ion-Releasing Tooth-Coating Material on Demineralization of Bovine Tooth Enamel

    PubMed Central

    Kawasaki, Koji; Kambara, Masaki

    2014-01-01

    We compared the effect of a novel ion-releasing tooth-coating material that contained S-PRG (surface-reaction type prereacted glass-ionomer) filler to that of non-S-PRG filler and nail varnish on the demineralization of bovine enamel subsurface lesions. The demineralization process of bovine enamel was examined using quantitative light-induced fluorescence (QLF) and electron probe microanalyzer (EPMA) measurement. Ion concentrations in demineralizing solution were measured using inductively coupled plasma atomic (ICP) emission spectrometry and an ion electrode. The nail varnish group and the non-S-PRG filler group showed linear demineralization. Although the nail varnish group and the non-S-PRG filler group showed linear demineralization, the S-PRG filler group did not. Further, plane-scanning by EPMA analysis in the S-PRG filler group showed no changes in Ca ion distribution, and F ions showed peak levels on the surface of enamel specimens. Most ions in the demineralizing solution were present at higher concentrations in the S-PRG filler group than in the other two groups. In conclusion, only the S-PRG filler-containing tooth-coating material released ions and inhibited demineralization around the coating. PMID:24578706

  3. Effect of umbilical cord mesenchymal stem cell in peri-implant bone defect after immediate implant: an experiment study in beagle dogs

    PubMed Central

    Hao, Peng-Jie; Wang, Zhi-Guo; Xu, Quan-Chen; Xu, Sheng; Li, Zhuo-Ri; Yang, Pi-Shan; Liu, Zhong-Hao

    2014-01-01

    Background: For the sake of reducing post extraction resorption, getting optimal positioning of the implant and shortening treatment time, immediate implant placement following tooth extraction has been proposed as a treatment option. However, the large bone defect peri-implant has a negative influence on the process of bone healing. In this study, umbilical cord mesenchymal stem cells (UCMSCs) were transplanted into the bone defect peri-implant inbeagle dogs and the effect of UCMSCs on bone regeneration in peri-implant were assessed. Methods: The mandibular second, third and fourth premolars of 8 beagle dogs were extracted bilaterally. The defects in one side were filled with platelet-rich fibrin (PRF) and then UCMSCs were injected into the defect area, while the defects in the other side were filled with PRF only as control group. The titanium implant was placed into the distal root socket of each extracted tooth. The animals were sacrificed at week 2, 4 and 8 post operative. The bone defects adjacent to the implant which are 4 mm in height, 4 mm in the mesio-distal direction and 3.5 mm in the bucco-lingual direction were made after immediate implant. Histomorphometric analysis was performed using methylene blue-fuchsin acid staining and hematoxylin and eosin (HE) staining to evaluate bone regeneration. Results: The direct bone-to-implant contact (BIC) in the experiment after 4 and 8 weeks was 56.47±1.18% and 76.23±2.08%; and in the control group was40.79±0.65% and 61.17±2.79%, respectively. The percentage of newly formed bone after 2, 4 and 8 weeks was 17.60±1.5%, 49.82±4.02% and 67.16±2.1% in experiment group; and in control group 14.30±1.25%, 37.04±2.29% and 58.83±3.36%, respectively. These results represented significant differences statistically. Conclusion: Intra-bone marrow injection of UCMSCs can promote new bone formation. UCMSCs can be used to as excellent seed cells to repair the large defect peri-implant after immediate implant. PMID:25550885

  4. Amery Ice Shelf's 'Loose Tooth' Gets Looser

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Amery Ice Shelf is an important dynamic system responsible for draining about 16% of the grounded East Antarctic ice sheet through only 2% of its coastline. Most of the mass input to the system occurs from the Lambert and several other glaciers. Mass loss from the system occurs through basal melting and iceberg calving. These images from the Multi-angle Imaging SpectroRadiometer (MISR) portray the ice shelf front on October 6, 2001 (top) and September 29, 2002 (bottom), and illustrate changes that took place over the year elapsed between the two views.

    Two longitudinal rifts, oriented roughly parallel to the direction of ice flow and measuring about 25 and 15 kilometers in length, are apparent near the seaward edge of the ice shelf. Between them, a transverse fracture extends eastward from the base of the western rift. This rift system is colloquially named the Amery 'loose tooth.' Over the course of the one-year interval between these two MISR images, the ice front has advanced approximately 1.6 - 1.7 kilometers, and the transverse fracture and a three-way fissure at the juncture of the rifts have widened. When the transverse fracture eventually reaches the eastern rift, a large iceberg (25 kilometers x 25 kilometers) will be released.

    These false-color multi-angle composites combine red-band data from MISR's 60o forward, nadir, and 60o aftward viewing cameras, displayed as red, green and blue, respectively. Different colors represent angular reflectance variations. Since generally smooth surfaces predominantly forward-scatter sunlight, these appear in shades of blue. Rough surfaces tend to backward-scatter sunlight, and these appear in shades of red or orange. Low clouds appear bright purple, since they exhibit both forward and backward-scattering. Using this technique, textural variations among ice types are revealed, and clouds can be easily distinguished from ice. Illumination conditions on the two dates are nearly identical.

    Understanding the 'normal' frequency of calving events from a particular ice shelf is necessary before it can be determined whether calving rates are changing. As part of an effort to determine the normal rate of ice flow and iceberg calving events, the Amery Ice Shelf front has been monitored by various remote sensing instruments for many years. The Amery Ice Shelf is currently considered to be about two-thirds of the way through a calving cycle. The last major calving event occurred in the early 1960's, when a massive iceberg (measuring about 140 kilometers x 70 kilometers) was released.

    The Amery 'loose tooth' is the subject of a joint field experiment during the 2002 austral summer, partially funded by NASA and undertaken by the Scripps Institution of Oceanography and the Australian Antarctic Division. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 9579 and 14807. The panels cover an area of about 204 kilometers x 110 kilometers, and utilize data from blocks 146 to 147 within World Reference System-2 paths 127 and 128, respectively. Data from the two orbital paths have been remapped to identical polar projections, and were cropped to include the same geographic area.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory,Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center,Greenbelt, MD. JPL is a division of the California Institute of Technology.

  5. Whole Genome Sequencing Reveals Novel Non-Synonymous Mutation in Ectodysplasin A (EDA) Associated with Non-Syndromic X-Linked Dominant Congenital Tooth Agenesis

    PubMed Central

    Sarkar, Tanmoy; Bansal, Rajesh; Das, Parimal

    2014-01-01

    Congenital tooth agenesis in human is characterized by failure of tooth development during tooth organogenesis. 300 genes in mouse and 30 genes in human so far have been known to regulate tooth development. However, candidature of only 5 genes viz. PAX9, MSX1, AXIN2, WNT10A and EDA have been experimentally established for congenitally missing teeth like hypodontia and oligodontia. In this study an Indian family with multiple congenital tooth agenesis was identified. Pattern of inheritance was apparently autosomal dominant type with a rare possibility to be X-linked. Whole genome sequencing of two affected individuals was carried out which revealed 119 novel non-synonymous single nucleotide variations (SNVs) distributed among 117 genes. Out of these only one variation (c.956G>T) located at exon 9 of X-linked EDA gene was considered as pathogenic and validated among all the affected and unaffected family members and unrelated controls. This variation leads to p.Ser319Ile change in the TNF homology domain of EDA (transcript variant 1) protein. In silico analysis predicts that this Ser319 is well conserved across different vertebrate species and a part of putative receptor binding site. Structure based homology modeling predicts that this amino acid residue along with four other amino acid residues nearby, those when mutated known to cause selective tooth agenesis, form a cluster that may have functional significance. Taken together these results suggest that c.956G>T (p.Ser319Ile) mutation plausibly reduces the receptor binding activity of EDA leading to distinct tooth agenesis in this family. PMID:25203534

  6. An Aberrant Splice Acceptor Site Due to a Novel Intronic Nucleotide Substitution in MSX1 Gene Is the Cause of Congenital Tooth Agenesis in a Japanese Family

    PubMed Central

    Tatematsu, Tadashi; Kimura, Masashi; Nakashima, Mitsuko; Machida, Junichiro; Yamaguchi, Seishi; Shibata, Akio; Goto, Hiroki; Nakayama, Atsuo; Higashi, Yujiro; Miyachi, Hitoshi; Shimozato, Kazuo; Matsumoto, Naomichi; Tokita, Yoshihito

    2015-01-01

    Congenital tooth agenesis is caused by mutations in the MSX1, PAX9, WNT10A, or AXIN2 genes. Here, we report a Japanese family with nonsyndromic tooth agenesis caused by a novel nucleotide substitution in the intronic region between exons 1 and 2 of the MSX1 gene. Because the mutation is located 9?bp before exon 2 (c.452-9G>A), we speculated that the nucleotide substitution would generate an abnormal splice site. Using cDNA analysis of an immortalized patient blood cell, we confirmed that an additional 7-nucleotide sequence was inserted at the splice junction between exons 1 and 2 (c.451_452insCCCTCAG). The consequent frameshift generated a homeodomain-truncated MSX1 (p.R151fsX20). We then studied the subcellular localization of truncated MSX1 protein in COS cells, and observed that it had a whole cell distribution more than a nuclear localization, compared to that of wild-type protein. This result suggests a deletion of the nuclear localization signal, which is mapped to the MSX1 homeodomain. These results indicate that this novel intronic nucleotide substitution is the cause of tooth agenesis in this family. To date, most MSX1 variants isolated from patients with tooth agenesis involve single amino acid substitutions in the highly conserved homeodomain or deletion mutants caused by frameshift or nonsense mutations. We here report a rare case of an intronic mutation of the MSX1 gene responsible for human tooth agenesis. In addition, the missing tooth patterns were slightly but significantly different between an affected monozygotic twin pair of this family, showing that epigenetic or environmental factors also affect the phenotypic variations of missing teeth among patients with nonsyndromic tooth agenesis caused by an MSX1 haploinsufficiency. PMID:26030286

  7. A Systematic Study on Tooth Enamel Microstructures of Lambdopsalis bulla (Multituberculate, Mammalia) - Implications for Multituberculate Biology and Phylogeny

    PubMed Central

    Mao, Fangyuan; Wang, Yuanqing; Meng, Jin

    2015-01-01

    Tooth enamel microstructure is a reliable and widely used indicator of dietary interpretations and data for phylogenetic reconstruction, if all levels of variability are investigated. It is usually difficult to have a thorough examination at all levels of enamel structures for any mammals, especially for the early mammals, which are commonly represented by sparse specimens. Because of the random preservation of specimens, enamel microstructures from different teeth in various species are often compared. There are few examples that convincingly show intraspecific variation of tooth enamel microstructure in full dentition of a species, including multituberculates. Here we present a systematic survey of tooth enamel microstructures of Lambdopsalis bulla, a taeniolabidoid multituberculate from the Late Paleocene Nomogen Formation, Inner Mongolia. We examined enamel structures at all hierarchical levels. The samples are treated differently in section orientations and acid preparation and examined using different imaging methods. The results show that, except for preparation artifacts, the crystallites, enamel types, Schmelzmuster and dentition types of Lambdopsalis are relatively consistent in all permanent teeth, but the prism type, including the prism shape, size and density, may vary in different portions of a single tooth or among different teeth of an individual animal. The most common Schmelzmuster of the permanent teeth in Lambdopsalis is a combination of radial enamel in the inner and middle layers, aprismatic enamel in the outer layer, and irregular decussations in tooth crown area with great curvature. The prism seam is another comparably stable characteristic that may be a useful feature for multituberculate taxonomy. The systematic documentation of enamel structures in Lambdopsalis may be generalized for the enamel microstructure study, and thus for taxonomy and phylogenetic reconstruction, of multituberculates and even informative for the enamel study of other early mammals. PMID:26020958

  8. Percutaneous and skeletal biocarbon implants

    NASA Technical Reports Server (NTRS)

    Mooney, V.

    1977-01-01

    Review of carbon implants developed by NASA discussed four different types of implants and subsequent improvements. Improvements could be of specific interest to rehabilitation centers and similar organizations.

  9. Crown Preservation of the Mandibular First Molar Tooth Impacts the Strength and Stiffness of Three Non-Invasive Jaw Fracture Repair Constructs in Dogs

    PubMed Central

    Lothamer, Charles; Snyder, Christopher John; Duenwald-Kuehl, Sarah; Kloke, John; McCabe, Ronald P.; Vanderby, Ray

    2015-01-01

    Repairing mandibular body fractures presents unique challenges not encountered when repairing long bones. Large tooth roots and the presence of the inferior alveolar neurovascular bundle limit safe placement for many types of orthopedic implants. Use of non-invasive fracture repair methods have increasingly become popular and have proven safe and effective at achieving bone healing. Non-invasive fixation constructs have not been tested in dogs using cantilevered bending. Furthermore, non-invasive fracture repair constructs have not been tested at the location of a common fracture location – the mandibular first molar tooth (M1). The objectives of this study were to test the strength and stiffness of three non-invasive mandibular fracture repair constructs and to characterize the impact that tooth crown preservation has on fixation strength for fractures occurring at the M1 location. Specimens were assigned to three treatment groups: (1) composite only, (2) interdental wiring and composite (IWC), and (3) transmucosal fixation screw and composite. For each pair of mandibles, one mandible received crown amputation at the alveolar margin to simulate the effect of crown loss on fixation strength and stiffness. Regardless of the status of crown presence, IWC demonstrated the greatest bending stiffness and load to failure. With the crown removed, IWC was significantly stronger compared to other treatments. All fixation constructs were stiffer when the tooth crown was preserved. In fractures at this location, retaining the tooth crown of M1 significantly increases stiffness of interdental wiring with composite and transmucosal screw with composite constructs. If the crown of M1 was removed, IWC was significantly stronger than the other two forms of fixation. PMID:26664947

  10. Tooth loss, chewing ability and quality of life

    PubMed Central

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

    2012-01-01

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

  11. Implantable, Ingestible Electronic Thermometer

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard

    1987-01-01

    Small quartz-crystal-controlled oscillator swallowed or surgically implanted provides continuous monitoring of patient's internal temperature. Receiver placed near patient measures oscillator frequency, and temperature inferred from previously determined variation of frequency with temperature. Frequency of crystal-controlled oscillator varies with temperature. Circuit made very small and implanted or ingested to measure internal body temperature.

  12. 41Ca - a possible neutron specific biomarker in tooth enamel

    NASA Astrophysics Data System (ADS)

    Wallner, A.; Arazi, A.; Faestermann, T.; Knie, K.; Korschinek, G.; Maier, H. J.; Nakamura, N.; Rühm, W.; Rugel, G.

    2004-08-01

    The measurement of long-lived radionuclides, produced by neutrons originating from the atomic-bomb explosions, offers the possibility to reconstruct neutron fluences to which survivors in Hiroshima and Nagasaki were exposed. The long-lived radionuclide, 41Ca (T1/2=103 000 years), is suggested here as a means for a retrospective determination of thermal neutron fluences, directly within the human body of a survivor. As proper material tooth enamel is proposed. The 41Ca signal in tooth enamel may be correlated with the exposure to A-bomb induced thermal neutron fluences, provided the natural background level of 41Ca/Ca is significantly lower. Therefore, tooth samples of unexposed survivors of the A-bomb explosions have been examined by means of accelerator mass spectrometry, in order to quantify the natural background level of 41Ca/Ca. Measured 41Ca/Ca ratios were confirmed to be as low as about 2 × 10-15. Thus, the A-bomb induced additional signal should be detectable for survivors at epidemiological relevant distances. Since tooth enamel had already been used as a dosemeter for gamma radiation from the A-bomb explosion, the detection of 41Ca in tooth enamel would allow, for the first time, an assessment of both, ?-ray and neutron exposures in the same biological material.

  13. Tooth wear among patients suffering from mental disorders

    PubMed Central

    Piccoli, Luca; Besharat, Laith Konstantinos; Cassetta, Michele; Migliau, Guido; Di Carlo, Stefano; Pompa, Giorgio

    2014-01-01

    Summary Aim Assess oral health, treatment needs and the correlation between tooth wear and medications in patients with psychiatric disease. Methodology 92 patients (40 male and 52 female) admitted in the Department of Neurology and Psychiatry of the Umberto I Hospital of Rome underwent an oral and dental clinical examination in accordance according to World Health Organization Basic Methods Criteria. One dentist performed all clinical examinations, training and calibration was carried out by an experienced clinical examiner. To measure the degree of inter-examiner agreement Kappa statistics was calculated. Level of tooth wear was assessed using the tooth wear classification of Johansson et al. Exact psychiatric pathology and medications of each patient were registrated. The Statistical Package for the Social Sciences (SPSS Inc., Chicago, Ill.) was used to analyze the data. A value of P < 0.05 was considered statistically significant. Results 34.78% of the sample regarding tooth wear demonstrated score 2. Men demonstrated 30% score 2, and 20% score 3 and 4 whereas female patients 38.46% score 2, 7.69% score 3 and none score 4. Conclusions Chronic exposure to neuroleptic drugs can cause phenomena of bruxism. There is a direct correlation between tooth wear, psychiatric disorders and administration of certain drugs. Poor oral hygiene and extensive unmet needs for dental treatment were widespread among psychiatric patients. PMID:25002918

  14. The development of complex tooth shape in reptiles.

    PubMed

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

    2014-01-01

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

  15. Efficient transport of droplet sandwiched between saw-tooth plates.

    PubMed

    Wang, Liya; Wu, Hengan; Wang, Fengchao

    2016-01-15

    The transport of droplet sandwiched between smooth and saw-tooth plates was investigated using molecular dynamics method. The repeated opening and closing of the plates result in sequential stretching and squeezing of the droplet, which provide the driving force. The asymmetrical saw tooth obstructs the backward motion of the droplet, and gives rise to a net forward displacement of the droplet in every opening and closing cycle. This unidirectional motion facilitates the efficient droplet transport, which is referred to as the ratchet-like effect in this work. Our simulations also reveal that the influence of the surface wettability on the droplet transport is different for saw-tooth and smooth plates. Droplet transport efficiency exhibits monotonic decrease with the increase of the solid-liquid interactions for saw-tooth plates. While for smooth plates, unidirectional droplet movement was only observed for certain solid-liquid interactions. Taken together these simulation results and theoretical analysis, we demonstrate that hydrophobic saw-tooth plates can improve the transport efficiency significantly. These findings not only enhance our understanding of the droplet transport from atomistic scale, but also are beneficial to practical applications in designing of micro- and nano-fluidic systems. PMID:26473277

  16. Retention of ion-implanted-xenon in olivine: Dependence on implantation dose

    NASA Technical Reports Server (NTRS)

    Melcher, C. L.; Tombrello, T. A.; Burnett, D. S.

    1982-01-01

    The diffusion of Xe in olivine, a major mineral in both meteorites and lunar samples, was studied. Xe ions were implanted at 200 keV into single-crystal synthetic-forsterite targets and the depth profiles were measured by alpha particle backscattering before and after annealing for 1 hour at temperatures up to 1500 C. The fraction of implanted Xe retained following annealing was strongly dependent on the implantation dose. Maximum retention of 100% occurred for an implantion dose of 3 x 10 to the 15th power Xe ions/sq cm. Retention was less at lower doses, with (approximately more than or = 50% loss at one hundred trillion Xe ions/sq cm. Taking the diffusion coefficient at this dose as a lower limit, the minimum activation energy necessary for Xe retention in a 10 micrometer layer for ten million years was calculated as a function of metamorphic temperature.

  17. Graphene for Biomedical Implants

    NASA Astrophysics Data System (ADS)

    Moore, Thomas; Podila, Ramakrishna; Alexis, Frank; Rao, Apparao; Clemson Bioengineering Team; Clemson Physics Team

    2013-03-01

    In this study, we used graphene, a one-atom thick sheet of carbon atoms, to modify the surfaces of existing implant materials to enhance both bio- and hemo-compatibility. This novel effort meets all functional criteria for a biomedical implant coating as it is chemically inert, atomically smooth and highly durable, with the potential for greatly enhancing the effectiveness of such implants. Specifically, graphene coatings on nitinol, a widely used implant and stent material, showed that graphene coated nitinol (Gr-NiTi) supports excellent smooth muscle and endothelial cell growth leading to better cell proliferation. We further determined that the serum albumin adsorption on Gr-NiTi is greater than that of fibrinogen, an important and well understood criterion for promoting a lower thrombosis rate. These hemo-and biocompatible properties and associated charge transfer mechanisms, along with high strength, chemical inertness and durability give graphene an edge over most antithrombogenic coatings for biomedical implants and devices.

  18. Platform switching and abutment emergence profile modification on peri-implant soft tissue.

    PubMed

    Dornbush, Jeffrey R; Reiser, Gary M; Ho, Daniel K

    2014-01-01

    Although the peri-implant hard tissue advantages of platform switching abutments have been well documented by many authors, the peri-implant soft tissue advantages of platform switching abutments has had limited mention. This article illustrates how the amount of peri-implant soft tissue volume is influenced by the dimensional extent of platform switching and the degree that an abutment's sulcular emergence profile has been modified. This article also introduces the term "abutment sulcular emergence profile enhancement" (ASEPE) to describe the combined effect of platform switching and abutment emergence profile modification. Three unrecognized clinical advantages of ASEPE are described by different clinical cases. First, elimination of excessive abutment impingement on gingival tissue adjacent to implants is achieved. Second, allowance for sufficient interproximal space between implant and adjacent tooth/implant for the entry of interproximal toothbrush is made possible. Third, excessive soft tissue blanching during abutment seating at prosthesis delivery is eliminated. Together, the combined application of platform switching and abutment emergence profile modification represents the opening of a new realm for managing soft tissue around implants to resolve dimensional problems. PMID:25269220

  19. Computerized Analysis of Digital Photographs for Evaluation of Tooth Movement

    PubMed Central

    Toodehzaeim, Mohammad Hossein; Karandish, Maryam; Karandish, Mohammad Nabi

    2015-01-01

    Objectives: Various methods have been introduced for evaluation of tooth movement in orthodontics. The challenge is to adopt the most accurate and most beneficial method for patients. This study was designed to introduce analysis of digital photographs with AutoCAD software as a method to evaluate tooth movement and assess the reliability of this method. Materials and Methods: Eighteen patients were evaluated in this study. Three intraoral digital images from the buccal view were captured from each patient in half an hour interval. All the photos were sent to AutoCAD software 2011, calibrated and the distance between canine and molar hooks were measured. The data was analyzed using intraclass correlation coefficient. Results: Photographs were found to have high reliability coefficient (P > 0.05). Conclusion: The introduced method is an accurate, efficient and reliable method for evaluation of tooth movement. PMID:26622272

  20. Tooth agenesis patterns in bilateral cleft lip and palate.

    PubMed

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

    2010-02-01

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

  1. OCT monitoring of diffusion of clearing agents within tooth dentin

    NASA Astrophysics Data System (ADS)

    Trunina, N. A.; Lychagov, V. V.; Tuchin, V. V.

    2009-08-01

    Monitoring of agent diffusion within tooth tissues is important in a wide context of tooth therapy (diffusion of medicinal preparations) and cosmetics (chemical whitening agents). We report here the results of optical coherence tomography (OCT) monitoring of diffusion of water and glycerol as clearing agents in samples of human tooth tissue. The diffusion process is analyzed by monitoring the changes in the OCT signal slope and the depth-resolved amplitude of OCT signal from a sample. Slow temporal kinetics of the mean attenuation coefficient was measured to monitor a saturable optical clearing due to the diffusion of the agent. The average permeability coefficient was estimated by dividing the measured thickness of the selected region by the time it took for the agent to diffuse through. The experimental results demonstrate that OCT can be an efficient tool in the study of agent diffusion through hard tissues.

  2. Role of Homeobox Genes in Tooth Morphogenesis: A Review

    PubMed Central

    Suryadeva, Sreevalli

    2015-01-01

    In oral cavity, disturbances due to genetic alterations may range from lack of tooth development to morphological defects. Due to technical advances in genetic engineering and molecular biology, valuable information regarding dentofacial growth could be studied in detailed manner. This helped us to explain the aetiology and pathogenesis of many dentofacial disorders. The success in treatment lies first in determining the aetiology of tooth anomalies and finally differentiating the effect of genes and environment on the orofacial diseases of that particular individual. Several genes belonging to class II homeobox families are expressed during odontogenesis however homeobox genes are not directly imvolved in tooth formation as they are not directly expressed in the first branchial arch derivatives. PMID:25859538

  3. ToothPrint, a proteomic database for dental tissues.

    PubMed

    Hubbard, M J; Faught, M J; Carlisle, B H; Stockwell, P A

    2001-01-01

    Increasing demand exists to disseminate and integrate proteomic data as proteome analysis assumes a commanding role in the postgenome era. Databases on the World Wide Web are an effective means to share information obtained from two-dimensional gels and allied proteomic approaches. Here we report the establishment of ToothPrint, a proteomic database for dental tissues accessed at http://toothprint.otago.ac.nz. Using developing rat enamel as a prototype, ToothPrint provides a variety of functionally relevant data (ligand binding, subcellular localisation, developmental regulation) in addition to protein identification maps. Features designed to enhance usability of the website and simplify its computing requirements are also outlined. Customized for mineralizing tissues, ToothPrint should prove to be an effective bioinformatic resource for investigations of dental biology. PMID:11680893

  4. Multidisciplinary Treatment Options of Tooth Avulsion Considering Different Therapy Concepts

    PubMed Central

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

    2014-01-01

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

  5. Interdisciplinary Treatment of a Fused Lower Premolar with Supernumerary Tooth

    PubMed Central

    Gadimli, Cengiz; Sari, Zafer

    2011-01-01

    The objective of this report is to describe combined orthodontic and endodontic treatment of a fused mandibular premolar with supernumerary tooth. The patient was a 15 year old girl seeking orthodontic treatment for the correction of maxillary and mandibular crowding. Cephalometric examination revealed skeletally Class I relationship. The panoramic radiograph showed a fused tooth with two separate pulp chambers and two separate root canals connecting in apical third. After the endodontic treatment of the fused teeth, the stripping of the supernumerary tooth was performed to establish a Class I canine relationship and to correct midline deviation. At the end of the treatment, the crowding was resolved and positive overjet and overbite was achieved. PMID:21769280

  6. Bizarre tooth surface loss and the Miswak stick.

    PubMed

    Karia, Roshni; Kelleher, Martin G

    2014-05-01

    Tooth surface loss can present in a variety of ways, some of which can appear rather strange on first examination. This case report demonstrates an unusual presentation of tooth surface loss (TSL) and its subsequent treatment. This loss of hard dental tissue appeared to be affecting the whole of the patient's remaining dentition, both lingually and buccally. Detailed questioning revealed the origins of this problem which turned out to be due to excessive use of an intra-oral Miswak chewing stick. Cinical Relevance: This article will enable clinicians to understand the importance of specific, targeted history-taking, involving a rare case of tooth surface loss as well as the use of minimally destructive restoration composites and a fibre-reinforced composite bridge. PMID:24930258

  7. From hopeless to good prognosis: journey of a failing tooth.

    PubMed

    Gupta, Saurabh; Deshmukh, Jeevanand; Khatri, Richa; Kulkarni, Vinaya Kumar; Karthik, B

    2015-02-01

    Chronic periodontitis, along with associated clinical findings such as pathologic tooth migration, diastema, functional and aesthetic aberrations, poses an immense challenge to a dental professional. These findings convert clinical decision making into a daunting task and adversely affect the prognosis and the treatment plan for the presenting clinical problem. An interdisciplinary approach aimed at restoring functional and aesthetic needs of the affected individual within the limitations of such a compromised clinical scenario may be a viable alternative to any radical treatment causing loss of natural tooth structure such as extraction. This article reports the usefulness of the interdisciplinary route for managing an otherwise hopeless clinical situation of chronic periodontitis complicated with extreme mobility and pathologic tooth migration, which resulted in compromised function and aesthetics. PMID:25859109

  8. White diet: is it necessary during tooth whitening?

    PubMed

    Matis, B A; Wang, G; Matis, J I; Cook, N B; Eckert, G J

    2015-01-01

    Patients are sometimes blamed for a reduced effect of bleaching when they do not adhere to a dentist's prescribed white diet. This study aimed to determine whether a white diet is necessary by evaluating the effects of coffee, tea, wine, and dark fruits on the potential tooth whitening during the bleaching process. Each of the effects of discoloration was categorized as "yes" or "no" based on a patient questionnaire. Data from five published studies were included in the analyses. Outcomes were based on the color change between baseline and the end of bleaching. The relationships between color changes were measured subjectively and objectively. A nonwhite diet was not significantly associated with less tooth whitening, and there was only a weak positive association between tooth whitening and diet for subjects who drank large amounts of coffee/tea. PMID:25748208

  9. Generation of gear tooth surfaces by application of CNC machines

    NASA Astrophysics Data System (ADS)

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

    1994-04-01

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

  10. Generation of gear tooth surfaces by application of CNC machines

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  11. Controlled implant/soft tissue interaction by nanoscale surface modifications of 3D porous titanium implants

    NASA Astrophysics Data System (ADS)

    Rieger, Elisabeth; Dupret-Bories, Agnès; Salou, Laetitia; Metz-Boutigue, Marie-Helene; Layrolle, Pierre; Debry, Christian; Lavalle, Philippe; Engin Vrana, Nihal

    2015-05-01

    Porous titanium implants are widely employed in the orthopaedics field to ensure good bone fixation. Recently, the use of porous titanium implants has also been investigated in artificial larynx development in a clinical setting. Such uses necessitate a better understanding of the interaction of soft tissues with porous titanium structures. Moreover, surface treatments of titanium have been generally evaluated in planar structures, while the porous titanium implants have complex 3 dimensional (3D) architectures. In this study, the determining factors for soft tissue integration of 3D porous titanium implants were investigated as a function of surface treatments via quantification of the interaction of serum proteins and cells with single titanium microbeads (300-500 ?m in diameter). Samples were either acid etched or nanostructured by anodization. When the samples are used in 3D configuration (porous titanium discs of 2 mm thickness) in vivo (in subcutis of rats for 2 weeks), a better integration was observed for both anodized and acid etched samples compared to the non-treated implants. If the implants were also pre-treated with rat serum before implantation, the integration was further facilitated. In order to understand the underlying reasons for this effect, human fibroblast cell culture tests under several conditions (directly on beads, beads in suspension, beads encapsulated in gelatin hydrogels) were conducted to mimic the different interactions of cells with Ti implants in vivo. Physical characterization showed that surface treatments increased hydrophilicity, protein adsorption and roughness. Surface treatments also resulted in improved adsorption of serum albumin which in turn facilitated the adsorption of other proteins such as apolipoprotein as quantified by protein sequencing. The cellular response to the beads showed considerable difference with respect to the cell culture configuration. When the titanium microbeads were entrapped in cell-laden gelatin hydrogels, significantly more cells migrated towards the acid etched beads. In conclusion, the nanoscale surface treatment of 3D porous titanium structures can modulate in vivo integration by the accumulative effect of the surface treatment on several physical factors such as protein adsorption, surface hydrophilicity and surface roughness. The improved protein adsorption capacity of the treated implants can be further exploited by a pre-treatment with autologous serum to render the implant surface more bioactive. Titanium microbeads are a good model system to observe these effects in a 3D microenvironment and provide a better representation of cellular responses in 3D.Porous titanium implants are widely employed in the orthopaedics field to ensure good bone fixation. Recently, the use of porous titanium implants has also been investigated in artificial larynx development in a clinical setting. Such uses necessitate a better understanding of the interaction of soft tissues with porous titanium structures. Moreover, surface treatments of titanium have been generally evaluated in planar structures, while the porous titanium implants have complex 3 dimensional (3D) architectures. In this study, the determining factors for soft tissue integration of 3D porous titanium implants were investigated as a function of surface treatments via quantification of the interaction of serum proteins and cells with single titanium microbeads (300-500 ?m in diameter). Samples were either acid etched or nanostructured by anodization. When the samples are used in 3D configuration (porous titanium discs of 2 mm thickness) in vivo (in subcutis of rats for 2 weeks), a better integration was observed for both anodized and acid etched samples compared to the non-treated implants. If the implants were also pre-treated with rat serum before implantation, the integration was further facilitated. In order to understand the underlying reasons for this effect, human fibroblast cell culture tests under several conditions (directly on beads, beads in suspension, beads encapsulated in gelatin

  12. Tooth Contact Shift in Loaded Spiral Bevel Gears

    NASA Technical Reports Server (NTRS)

    Savage, M.; Altidis, P. C.; Lewicki, D. G.; Coy, J. J.; Litvin, F. L.

    1989-01-01

    An analytical method is presented to predict the shifts of the contact ellipses of spiral bevel gear teeth under load. The contact ellipse shift is the motion of the tooth contact position from the ideal pitch point to its location under load. The shifts are due to the elastic motions of the gear and pinion supporting shafts and bearings. The calculations include the elastic deflections of the gear shafts and the deflections of the four shaft bearings. The method assumes that the surface curvature of each tooth is constant near the unloaded pitch point. Results from these calculations will help designers reduce transmission weight without seriously reducing transmission performance.

  13. Crystal structure of human tooth enamel studied by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Ouladdiaf, Bachir; Rodriguez-Carvajal, Juan; Goutaudier, Christelle; Ouladdiaf, Selma; Grosgogeat, Brigitte; Pradelle, Nelly; Colon, Pierre

    2015-02-01

    Crystal structure of human tooth enamel was investigated using high-resolution neutron powder diffraction. Excellent agreement between observed and refined patterns is obtained, using the hexagonal hydroxyapatite model for the tooth enamel, where a large hydroxyl deficiency ˜70% is found in the 4e site. Rietveld refinements method combined with the difference Fourier maps have revealed, however, that the hydroxyl ions are not only disordered along the c-axis but also within the basal plane. Additional H ions located at the 6h site and forming HPO42- anions were found.

  14. Tooth resorption part II - external resorption: Case series.

    PubMed

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

    2013-03-01

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

  15. [The combination of a fused tooth and a supernumerary central incisor: a possible treatment plan].

    PubMed

    Leemans, P; Vinckier, F; Carels, C

    2005-08-01

    An 8-year old boy was referred to the orthodontic department because of a fused tooth. The clinical and radiological examination showed that - besides the double tooth at the region of the 21 - there was a normal tooth 22 in eruption as well. Moreover a still impacted supernumerary tooth was present in the right upper front region. The treatment included the extraction of the fused tooth and an autotransplantation of the supernumerary tooth to the extraction site of the fused tooth. During the follow-up period the pulp showed a progressive obliteration starting at the crown level with a conservation of the vitality. Apexification of the root of the transplanted tooth proceeded successfully. Furthermore a review of the literature is given in this article on the aetiology and treatment of fused teeth and on the application of autotransplantation. PMID:16128216

  16. Scales and Tooth Whorls of Ancient Fishes Challenge Distinction between External and Oral ‘Teeth’

    PubMed Central

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

    2013-01-01

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

  17. Regeneration of tooth-like hydroxyapatite depended on amelogenin functional section monolayer: a new approach for tooth repair.

    PubMed

    Tian, Kun; Peng, Min; Ren, Xiaohua; Liao, Chuhang; Fei, Wei

    2012-08-01

    Tooth defect due to caries, trauma, or acid corrosion are common in mankind. Ceramics, metal and resin were used to repaired tooth defect in the past hundred years, but they cannot instead enamel and dentin in depth in clinic usage for the difference in structure and element. So the formation of organized nanocrystals that resemble enamel is crucial for successful enamel remineralization. Now synthesizing a mimicking structure of human enamel using acellular methods has attracted much interest from research groups who have tried using recombinant enamel making proteins like amelogenin, surfactants, to mimic the biomineralization process to restore the enamel layer. Since amelogenin can be used in the assembly of functional nanostructures, we hypothesis that rationally designed ?-sheet-forming peptides that spontaneously form three-dimensional fibrillar scaffolds in response to specific environmental triggers may potentially be used in inducing tooth-like hydroxyapatite crystal ex vivo which important to treatment/prevention of dental caries, via bioactive surface groups. PMID:22564781

  18. Influence of implant inclination associated with mandibular class I removable partial denture.

    PubMed

    de Freitas Santos, Ciandrus Moraes; Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; de Moraes, Sandra Lúcia Dantas; Falcón-Antenucci, Rosse Mary

    2011-03-01

    The aim of this study was to use two-dimensional finite element method to evaluate the displacement and stress distribution transmitted by a distal extension removable partial denture (DERPD) associated with an implant placed at different inclinations (0, 5, 15, and 30 degrees) in the second molar region of the edentulous mandible ridge. Six hemimandibular models were created: model A, only with the presence of the natural tooth 33; model B, similar to model A, with the presence of a conventional DERPD replacing the missing teeth; model C, similar to the previous model, with a straight implant (0 degrees) in the distal region of the ridge, under the denture base; model D, similar to model C, with the implant angled at 5 degrees in the mesial direction; model E, similar to model C, with the implant angled at 15 degrees in the mesial direction; and model F, similar to ME, with the implant angled at 30 degrees in the mesial direction. The models were created with the use of the AutoCAD 2000 program (Autodesk, Inc, San Rafael, CA) and processed for finite element analysis by the ANSYS 8.0 program (Swanson Analysis Systems, Houston, PA). The force applied was vertical of 50 N on each cusp tip. The results showed that the introduction of the RPD overloaded the supporting structures of the RPD and that the introduction of the implant helped to relieve the stresses of the mucosa alveolar, cortical bone, and trabecular bone. The best stress distribution occurred in model D with the implant angled at 5 degrees. The use of an implant as a support decreased the displacement of alveolar mucosa for all inclinations simulated. The stress distribution transmitted by the DERPD to the supporting structures was improved by the use of straight or slightly inclined implants. According to the displacement analysis and von Mises stress, it could be expected that straight or slightly inclined implants do not represent biomechanical risks to use. PMID:21415633

  19. Tooth movements are guided by specific contact areas between the tooth root and the jaw bone: A dynamic 3D microCT study of the rat molar.

    PubMed

    Naveh, Gili R S; Shahar, Ron; Brumfeld, Vlad; Weiner, Steve

    2012-02-01

    Teeth sustain high loads over a lifetime and yet intact tooth failure is rare. The different structures of the tooth, jaw bone and the intervening soft periodontal ligament enable the tooth to endure repeated loading during mastication. Although mechanical and functional properties of the different components are thoroughly investigated, the manner in which the whole tooth functions under load is still enigmatic. A custom-made loading system inside a microCT scanner was used to directly visualize the root movements in relation to the jaw bone as the rat molar tooth was loaded. At low loads no contact was observed between the root surface and the bone, whereas at higher loads three specific contact areas between the root surface and the jaw bone were observed. These contact areas restrict tooth movement in the buccal-lingual direction, but enable the tooth to rock in a "seesaw" like manner in the distal-mesial direction. The contact areas appear to play a role in determining tooth motion and in turn define the manner in which the whole tooth moves when loaded. These observations are important for understanding basic structure-function relations of the tooth-PDL-bone system, and have direct implications for better understanding pathological and therapeutic processes in orthodontics, periodontics and jaw bone regeneration. PMID:22138090

  20. The assessing method of complete tooth form error based on the spline function

    NASA Astrophysics Data System (ADS)

    Huang, Fugui; Cui, Changcai; Zhang, Rencheng

    2006-11-01

    Having analyzed the shortcoming of current measurement method of involute cylinder gear wheel tooth form error and the reason of error, measurement theory and implementation method of the complete tooth form error of the involute cylindrical gear have been proposed; mathematical model of fitting actual tooth curve based on cubic spline function has been derived and the determination of boundary condition has been given; feasibility of measurement and evaluation method for complete tooth form error has been verified by experiment.

  1. Silicon saw-tooth refractive lens for high-energy x-rays made using a diamond saw.

    SciTech Connect

    Said, A. H.; Shastri, S. D.; X-Ray Science Division

    2010-01-01

    Silicon is a material well suited for refractive lenses operating at high X-ray energies (>50 keV), particularly if implemented in a single-crystal form to minimize small-angle scattering. A single-crystal silicon saw-tooth refractive lens, fabricated by a dicing process using a thin diamond wheel, was tested with 115 keV X-rays, giving an ideal 17 {mu}m line focus width in a long focal length, 2:1 ratio demagnification geometry, with a source-to-focus distance of 58.5 m. The fabrication is simple, using resources typically available at any synchrotron facility's optics shop.

  2. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  3. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  4. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  5. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  6. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  7. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Backing and facing for an artificial tooth. 872.3910 Section 872.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended...

  8. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  9. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  10. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  11. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Backing and facing for an artificial tooth. 872.3910 Section 872.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended...

  12. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Backing and facing for an artificial tooth. 872.3910 Section 872.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended...

  13. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  14. 21 CFR 872.3900 - Posterior artificial tooth with a metal insert.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Posterior artificial tooth with a metal insert... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal insert. (a) Identification. A posterior artificial tooth with a metal insert is...

  15. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Backing and facing for an artificial tooth. 872.3910 Section 872.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended...

  16. 21 CFR 872.3910 - Backing and facing for an artificial tooth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Backing and facing for an artificial tooth. 872.3910 Section 872.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... artificial tooth. (a) Identification. A backing and facing for an artificial tooth is a device intended...

  17. UNCORRECTEDPROOF 2 Mitochondrial fusion and function in CharcotMarieTooth type

    E-print Network

    Shaw, Janet M.

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

  18. Ion implantation at elevated temperatures

    SciTech Connect

    Lam, N.Q.; Leaf, G.K.

    1985-11-01

    A kinetic model has been developed to investigate the synergistic effects of radiation-enhanced diffusion, radiation-induced segregation and preferential sputtering on the spatial redistribution of implanted solutes during implantation at elevated temperatures. Sample calculations were performed for Al and Si ions implanted into Ni. With the present model, the influence of various implantation parameters on the evolution of implant concentration profiles could be examined in detail.

  19. Speech and Literacy Development in a Child with a Cochlear Implant: Application of a Psycholinguistic Framework

    ERIC Educational Resources Information Center

    Pascoe, Michelle; Randall-Pieterse, Candice; Geiger, Martha

    2013-01-01

    This single case study describes the speech, phonological awareness and literacy of a 6;0-year-old girl with a cochlear implant. NG, a child with a congenital bilateral severe/profound hearing loss, received a monaural cochlear implant at the age of 3;0, three years prior to the study. Using a psycholinguistic framework to investigate her single

  20. Investigation of Carbon ion-implanted waveguides in tungsten bronze (Ca0.28Ba0.72)0.25(Sr0.6Ba0.4)0.75Nb2O6 single crystal

    NASA Astrophysics Data System (ADS)

    Jiao, Yang; Wang, Chuan-Kui; Li, Zong-Liang; Ren, Ying-Ying

    2014-09-01

    Planar optical waveguides were fabricated in (Ca0.28Ba0.72)0.25(Sr0.6Ba0.4)0.75Nb2O6 (CSBN25) crystal by 6.0-MeV C+ ion implantation with fluences of 2, 4 and 6 × 1014 ions/cm2 at room temperature. The mode parameters, refractive indices profiles are measured and the refractive indices behavior in the waveguide region is discussed. The shape of nuclear energy loss distribution of the C+ implantation was similar to those of the waveguide refractive index profiles, which means an inherent relationship between the waveguide formation and the energetic energy deposition. The extraordinary refractive index has a small positive change in the surface region after the implantation.

  1. Transition from failing dentition to complete-arch implant rehabilitation with a staged approach: a 3-year clinical report.

    PubMed

    Papaspyridakos, Panos; Chronopoulos, Vasilios

    2014-09-01

    The transition of patients from failing dentition to complete-arch implant rehabilitation often means that the patient is rendered edentulous and has to wear a removable complete denture for a time. Many patients find this objectionable. A staged treatment approach provides a fixed interim prosthesis for use throughout the rehabilitation process, allowing patient comfort and prosthodontic control. This clinical report describes a staged approach protocol with a new type of interim prosthesis. The prosthesis is supported by hopeless teeth and the soft tissues of the maxillary tuberosities and mandibular retromolar pads for the complete-arch implant rehabilitation of a patient with failing dentition. This protocol allows for a fixed interim prosthesis with combined tooth and mucosa or implant support during the entire rehabilitation process, thus avoiding the use of complete dentures. The implants and prostheses were functioning successfully after 3 years of clinical service. PMID:24631159

  2. Method of fabricating optical waveguides by ion implantation doping

    DOEpatents

    Appleton, Bill R. (Oak Ridge, TN); Ashley, Paul R. (Toney, AL); Buchal, Christopher J. (Juelich, DE)

    1989-01-01

    A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO.sub.3 crystals are implanted with high concentrations of Ti dopant at ion energies of about 350 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000.degree. C. produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality single crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguides properties.

  3. Biocompatibility of surgical implants

    NASA Technical Reports Server (NTRS)

    Kaelble, D. H.

    1979-01-01

    Method of selecting biocompatible materials for surgical implants uses fracture mechanic relationships and surface energies of candidate materials in presence of blood plasma. Technique has been used to characterize 190 materials by parameters that reflect their biocompatibility.

  4. Risks of Breast Implants

    MedlinePLUS

    ... larger and longer than these conducted so far. Breastfeeding Some women who undergo breast augmentation can successfully ... breast implant silicone shell into breast milk during breastfeeding. Although there are currently no established methods for ...

  5. Superelastic Orthopedic Implant Coatings

    NASA Astrophysics Data System (ADS)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  6. October 2008 ROUGH-TOOTHED DOLPHIN (Steno bredanensis)

    E-print Network

    - toothed dolphins in the Canary Islands in waters from 20 m to 2,500 m, with the average depth reported) and Ritter (2002). These dolphins are typically seen in small groups of 10-20 animals (Wade and Gerrodette, namely groups of 45 animals in the Atlantic (CETAP 1982), over 50 animals in the eastern tropical Pacific

  7. Overview of Cannery Building, note the saw tooth monitors with ...

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

    Overview of Cannery Building, note the saw tooth monitors with glazing and with corrugated fiberglass and screens, view facing north - Kahului Cannery, Plant No. 28, Cannery Building and Dryer House/Feed Storage Building, 120 Kane Street, Kahului, Maui County, HI

  8. Computer-aided engineering analysis of tooth-bending

    E-print Network

    Grujicic, Mica

    this problem, a significant increase in long-term gearbox reliability needs to be achieved. Design/methodology/approach ­ While purely empirical efforts aimed at identifying shortcomings in the current design of the gearboxes-life of a wind-turbine gearbox in the case when the service-life is controlled by the gear-tooth bending

  9. Tooth Loss 1 December, 2014 Center for Health Systems

    E-print Network

    Gopalakrishnan, K.

    than $15,000, or African Americans. Age: While nearly 80% of adults younger than age 35 reported/ethnicity: Fifty five percent of Whites retained all teeth whereas 39% of African Americans and 35% of Native among tooth loss, health, and health-related behaviors using data from North Carolina Behavioral Risk

  10. Reducing Baby Bottle Tooth Decay. A SERVE Research Brief.

    ERIC Educational Resources Information Center

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

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

  11. Prosthetic clone and natural human tooth comparison by speckle interferometry

    NASA Astrophysics Data System (ADS)

    Slangen, Pierre; Corn, Stephane; Fages, Michel; Raynal, Jacques; Cuisinier, Frederic J. G.

    2010-09-01

    New trends in dental prosthodontic interventions tend to preserve the maximum of "body" structure. With the evolution of CAD-CAM techniques, it is now possible to measure "in mouth" the remaining dental tissues. The prosthetic crown is then designed using this shape on which it will be glued on, and also by taking into account the contact surface of the opposite jaw tooth. Several theories discuss on the glue thickness and formulation, but also on the way to evolve to a more biocompatible crown and also new biomechanical concepts. In order to validate these new concepts and materials, and to study the mechanical properties and mechanical integrity of the prosthesis, high resolution optical measurements of the deformations of the glue and the crown are needed. Samples are two intact premolars extracted for orthodontics reasons. The reference sample has no modifications on the tooth while the second sample tooth is shaped to receive a feldspathic ceramic monoblock crown which will be glued. This crown was manufactured with a chairside CAD-CAM system from an intra-oral optical print. The software allows to realize a nearly perfect clone of the reference sample. The necessary space for the glue is also entered with ideal values. This duplication process yields to obtain two samples with identical anatomy for further processing. The glue joint thickness can also be modified if required. The purpose is to compare the behaviour of a natural tooth and its prosthetic clone manufactured with "biomechanical" concepts. Vertical cut samples have been used to deal with planar object observation, and also to look "inside" the tooth. We have developed a complete apparatus enabling the study of the compressive mechanical behaviour of the concerned tooth by speckle interferometry. Because in plane displacements are of great interest for orthodontic measurements1, an optical fiber in-plane sensitive interferometer has been designed. The fibers are wrapped around piezoelectric transducers to perform "4-buckets" phase shifting leading to phase variations during the compression test. In-plane displacement fields from speckle interferometry already showed very interesting data concerning the mechanical behaviour of teeth: the dentine-enamel junction (DEJ) and the glue junction have been shown including their interfacing function. Mechanical action of the tooth surrounding medium will also be discussed.

  12. Simple Implant Augmentation Rhinoplasty.

    PubMed

    Nguyen, Anh H; Bartlett, Erica L; Kania, Katarzyna; Bae, Sang Mo

    2015-11-01

    Augmentation rhinoplasty among Asian patients is often performed to improve the height of the nasal dorsum. As the use of autogenous tissues poses certain limitations, alloplastic materials are a viable alternative with a long history of use in Asia. The superiority of one implant prosthesis over another for augmentation rhinoplasty is a matter of debate, with each material representing varying strengths and weaknesses, indications for use, and precautions to consider in nasal implant placement. An implant prosthesis should be used on a case-by-case basis. Augmentation rhinoplasty requires the consideration of specific anatomical preoperative factors, including the external nose, nasal length, nasofrontal angle, humps, and facial proportions. It is equally important to consider several operative guidelines to appropriately shape implants to minimize the occurrence of adverse effects and postoperative complications. The most common postoperative complications include infection, nasal height change, movement of implant prosthesis, and silicone implant protrusion. In addition, the surgeon should consider the current standards of Asian beauty aesthetics to better understand the patient's desired outcome. PMID:26648804

  13. Biomaterials in cochlear implants

    PubMed Central

    Stöver, Timo; Lenarz, Thomas

    2011-01-01

    The cochlear implant (CI) represents, for almost 25 years now, the gold standard in the treatment of children born deaf and for postlingually deafened adults. These devices thus constitute the greatest success story in the field of ‘neurobionic’ prostheses. Their (now routine) fitting in adults, and especially in young children and even babies, places exacting demands on these implants, particularly with regard to the biocompatibility of a CI’s surface components. Furthermore, certain parts of the implant face considerable mechanical challenges, such as the need for the electrode array to be flexible and resistant to breakage, and for the implant casing to be able to withstand external forces. As these implants are in the immediate vicinity of the middle-ear mucosa and of the junction to the perilymph of the cochlea, the risk exists – at least in principle – that bacteria may spread along the electrode array into the cochlea. The wide-ranging requirements made of the CI in terms of biocompatibility and the electrode mechanism mean that there is still further scope – despite the fact that CIs are already technically highly sophisticated – for ongoing improvements to the properties of these implants and their constituent materials, thus enhancing the effectiveness of these devices. This paper will therefore discuss fundamental material aspects of CIs as well as the potential for their future development. PMID:22073103

  14. Fracture resistance of tooth fragment reattachment: effects of different preparation techniques and adhesive materials.

    PubMed

    Pusman, Esin; Cehreli, Zafer C; Altay, Nil; Unver, Bahtiyar; Saracbasi, Osman; Ozgun, Gungor

    2010-02-01

    The purpose of this study was to evaluate and compare the bond strengths of experimentally fractured human tooth fragments reattached with different adhesive materials and retentive techniques in vitro. Uncomplicated crown fractures were obtained on intact human mandibular permanent incisors by applying perpendicular load to the buccal aspect of tooth crowns. Fractured teeth were randomly assigned into one of three reattachment protocols: (i) Simple reattachment, (ii) Overcontour preparation, and (iii) Internal dentin groove. The first and second groups were divided into 10 subgroups, and the third group into five subgroups (n = 10 per group) with respect to five different adhesive systems (Prime&Bond NT, Adper Single Bond II, Adper Prompt L-Pop, Clearfil S(3) Bond, G Bond) used with or without a hybrid resin composite (Z250). Restored teeth were subjected to thermal cycling, and subsequently to the same loading protocol used for fracturing intact teeth. Fracture strength after reattachment procedures was recorded as a percentage of the original fracture strength. Both type of adhesive material and placement of an intermediate layer of resin composite affected the fracture resistance (P < 0.05). The highest fracture strength recovery was obtained using the internal dentin groove technique (54 +/- 0.58%, P < 0.05), followed by the overcontour and simple reattachment protocols (49 +/- 0.58% and 32 +/- 0.82%, respectively, P < 0.05). Ultramorphological evaluation of bonded specimens revealed voids and microcracks along the adhesive interface, which might contribute to postadhesive failure. PMID:20089057

  15. In vitro and in situ erosion models for evaluating tooth substance loss.

    PubMed

    West, N X; Davies, M; Amaechi, B T

    2011-01-01

    Because of the difficulties in measuring erosion in vivo, a number of in vitro and in situ models have been developed and validated. These models are flexible and informative, allowing single as well as multiple variables to be examined under specific conditions using accurate measurement techniques over defined timelines, thus yielding useful data without harmful effects on individuals. This information, together with clinical findings, is essential for clinicians advising susceptible patients appropriately regarding the management of their condition. Little guidance is available, however, on the standardisation of in vitro and in situ protocols for erosive tooth wear studies, so it is difficult to make meaningful comparisons between investigations as experimental variables differ widely from study to study. The aim of this review was to collate the available data on models designed to assess erosive challenges which are severe enough to cause tissue loss as opposed to just softening of the surface structure. The different types of models, with their merits and pitfalls, are documented. Test substrates, disinfecting regimens and ethical considerations are discussed. The aims of this paper are to give guidance to the researcher on evidence-based in vitro and in situ erosive tooth wear methodology and to suggest best practice given current knowledge. PMID:21625132

  16. Assignment of a second Charcot-Marie-Tooth type II locus to chromosome 3q

    SciTech Connect

    Kwon, J.M.; Elliott, J.L.; Yee, W.C.

    1995-10-01

    Charcot-Marie-Tooth disease (CMT) is the most common inherited motor and sensory neuropathy. The neuronal form of this disorder is referred to as Charcot-Marie-Tooth type II disease (CMT2). CMT2 is usually inherited as an autosomal dominant trait with a variable age at onset of symptoms associated with progressive axonal neuropathy. In some families, the locus that predisposes to CMT2 has been demonstrated to map to the distal portion of the short arm of chromosome 1. Other families with CMT2 do not show linkage with 1p markers, suggesting genetic heterogeneity in CMT2. We investigated linkage in a single large kindred with autosomal dominant CMT2. The gene responsible for CMT2 in this kindred (CMT2B) was mapped to the interval between the microsatellite markers D3S1769 and D3S1744 in the 3q13-22 region. Study of additional CMT2 kindreds should serve to further refine the disease gene region and may ultimately lead to the identification of a gene defect that underlies the CMT2 phenotype. 21 refs., 3 figs., 1 tab.

  17. Integration of High Dose Boron Implants--Modification of Device Parametrics through Implant Temperature Control

    SciTech Connect

    Schmeide, Matthias; Ameen, M. S.; Kondratenko, Serguei; Krimbacher, Bernhard; Reece, Ronald N.

    2011-01-07

    In the present study, we have extended a previously reported 250 nm logic p-S/D implant (7 keV B 4.5x10{sup 15} cm{sup -2}) process matching exercise [5] to include wafer temperature, and demonstrate that matching can be obtained by increasing the temperature of the wafer during implant. We found that the high dose rate delivered by the single wafer implanter caused the formation of a clear amorphous layer, which upon subsequent annealing altered the diffusion, activation, and clustering properties of the boron. Furthermore, increasing the temperature of the wafer during the implant was sufficient to suppress amorphization, allowing profiles and device parameters to become matched. Figure 5 shows a representative set of curves indicating the cluster phenomena observed for the lower temperature, high flux single wafer implanter, and the influence of wafer temperature on the profiles. The results indicate the strong primary effect of dose rate in determining final electrical properties of devices, and successful implementation of damage engineering using wafer temperature control.

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

    PubMed

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

    2014-05-01

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

  19. Photometric assessment of tooth color using commonly available software.

    PubMed

    Denissen, Harry; Dozic, Alma

    2010-01-01

    It would be expedient to develop a simple digital procedure for matching shade guides to teeth for dental restorations. It was hypothesized that precise and objective L*a*b* measurements could be performed on photographic images of teeth and shade guides using commonly available photo software. Tooth shade guide tabs, shaped like computer-generated posterior crowns, were used for color matching. Digital photographs were obtained of the vestibular surface of the tooth and the neighboring shade guide. Sections of the tooth and shade guide on the photograph were cropped and analyzed in Photoshop CS2. The precision error of the measurements was expressed as the coefficient of variation in percent. The effects of tolerance setting and number of measurements and analysts were evaluated. The difference in color was calculated as the DeltaE L*a*b*. The precision errors of the L*a*b* measurements with a tolerance setting of 6 pixels were better than 1.3%. There was no significant difference between one and five repeated measurements or between the measurements and the precision errors of two analysts. Color differences (DeltaE) between repeated measurements were below 0.5 units, thus reproducible and visually identical. DeltaE L*a*b* calculations were expedient for matching a particular color guide tab to the neighboring tooth. The color coordinates L*a*b* of teeth and shade guides can be calculated with a precision error of only 1.3%, using readily available software. A tolerance setting of 6 pixels is optimal and only one measurement and one analyst are necessary for objective and precise measurements. The described digital L*a*b* measurements on a photograph offer the dentist and the ceramist a simple, precise, and objective tool for matching tooth and shade guide. PMID:20589263

  20. Assessment of gliosis around moveable implants in the brain

    NASA Astrophysics Data System (ADS)

    Stice, Paula; Muthuswamy, Jit

    2009-08-01

    Repositioning microelectrodes post-implantation is emerging as a promising approach to achieve long-term reliability in single neuronal recordings. The main goal of this study was to (a) assess glial reaction in response to movement of microelectrodes in the brain post-implantation and (b) determine an optimal window of time post-implantation when movement of microelectrodes within the brain would result in minimal glial reaction. Eleven Sprague-Dawley rats were implanted with two microelectrodes each that could be moved in vivo post-implantation. Three cohorts were investigated: (1) microelectrode moved at day 2 (n = 4 animals), (2) microelectrode moved at day 14 (n = 5 animals) and (3) microelectrode moved at day 28 (n = 2 animals). Histological evaluation was performed in cohorts 1-3 at four-week post-movement (30 days, 42 days and 56 days post-implantation, respectively). In addition, five control animals were implanted with microelectrodes that were not moved. Control animals were implanted for (1) 30 days (n = 1), (2) 42 days (n = 2) and (3) 56 days (n = 2) prior to histological evaluation. Quantitative assessment of glial fibrillary acidic protein (GFAP) around the tip of the microelectrodes demonstrated that GFAP levels were similar around microelectrodes moved at day 2 when compared to the 30-day controls. However, GFAP expression levels around microelectrode tips that moved at day 14 and day 28 were significantly less than those around control microelectrodes implanted for 42 and 56 days, respectively. Therefore, we conclude that moving microelectrodes after implantation is a viable strategy that does not result in any additional damage to brain tissue. Further, moving the microelectrode downwards after 14 days of implantation may actually reduce the levels of GFAP expression around the tips of the microelectrodes in the long term.

  1. Assessment of Tooth Preparation via Er:YAG Laser and Bur on Microleakage of Dentin Adhesives

    PubMed Central

    Bahrololoomi, Zahra; Heydari, Elham

    2014-01-01

    Objective Microleakage can be responsible for tooth hypersensitivity, secondary caries, and the possibility of pathological pulp alterations in restored teeth. Recently, alternative methods for tooth preparation such as laser irradiation have been studied; but there are limited studies on primary teeth. The aim of this in vitro study was to compare the degree of microleakage of composite restorations prepared by Er:YAG laser and conventional bur preparation with two adhesive systems in primary teeth. Materials and Methods: Eighty primary canine teeth were randomly divided into 4 groups. Class V cavities were prepared by Er:YAG laser or diamond bur on buccal surface. The groups were as follows: group1: High speed drill + self-etching adhesive Adper Prompt-L-Pop, group 2: Er:YAG laser + etch & rinse adhesive Adper Single Bond, group 3: High speed drill + Adper Single Bond, group 4: Er:YAG laser + Adper Prompt-L-Pop. Cavities were restored with Filtek Z250 composite resin. Then all of the specimens were polished, thermocycled, immersed in 2% methylene blue solution and sectioned longitudinally. Degree of microleakage was evaluated by two evaluators who assigned the micrleakage score (0 to 3). The original data were analyzed by the Kruskal-Wallis and Dunn’s tests. Results: There were significant differences between bur-prepared cavities in the Adper Single Bond and other groups. There were no statistically significant differences between other groups. Conclusion: Laser-prepared cavities showed higher microleakage scores than cavities prepared with diamond bur with etch and rinse adhesive system. No significant difference was revealed between the laser and bur-prepared cavities using self-etch primers. PMID:24910693

  2. Immune tolerance of mice allogenic tooth transplantation induced by immature dendritic cells

    PubMed Central

    Li, Wenying; Deng, Feng; Wang, Yu; Ma, Ce; Wang, Yurong

    2015-01-01

    As a common procedure in dentistry for replacing a missing tooth, allogenic tooth transplantation has encountered many difficulties in the clinical application because of immunological rejection. It is hypothesized that immature dendritic cell injection might be a potential alternative method to avoid or alleviate immunological rejection in allogenic tooth transplantation. To test this hypothesis, a mouse model of allogenic and autogeneic tooth transplantation was to established test the immunosuppressive effect of immature dendritic cells (imDCs) derived from donor bone marrows on transplant rejection in allogenic tooth transplantation. 2 × 106 imDCs generated with 50 U/ml GM-CSF were injected to each recipient mouse by two ways: tail vein injection 7 days before transplantation or regional dermal injection at day 0 and day 3 after transplantation. Groups of autogeneic tooth transplantation and allogenic tooth transplantation without any treatment were set as control groups. The effects were evaluated with histopathology and immunohistochemistry. We found there was no obvious rejection in autogeneic tooth transplantation group; tail intravenous injection group showed obviously alleviated rejection while local injection group and none-treatment allogenic tooth transplantation group both showed severe rejection. Our results suggested that the rejection of allogenic tooth transplantation could be alleviated by tail vein injection of donor bone marrow-derived imDCs though it could not be completely eliminated. The clinical application of imDCs in allogenic tooth transplantation still needs further deep research. PMID:26131099

  3. Distinct developmental genetic mechanisms underlie convergently evolved tooth gain in sticklebacks.

    PubMed

    Ellis, Nicholas A; Glazer, Andrew M; Donde, Nikunj N; Cleves, Phillip A; Agoglia, Rachel M; Miller, Craig T

    2015-07-15

    Teeth are a classic model system of organogenesis, as repeated and reciprocal epithelial and mesenchymal interactions pattern placode formation and outgrowth. Less is known about the developmental and genetic bases of tooth formation and replacement in polyphyodonts, which are vertebrates with continual tooth replacement. Here, we leverage natural variation in the threespine stickleback fish Gasterosteus aculeatus to investigate the genetic basis of tooth development and replacement. We find that two derived freshwater stickleback populations have both convergently evolved more ventral pharyngeal teeth through heritable genetic changes. In both populations, evolved tooth gain manifests late in development. Using pulse-chase vital dye labeling to mark newly forming teeth in adult fish, we find that both high-toothed freshwater populations have accelerated tooth replacement rates relative to low-toothed ancestral marine fish. Despite the similar evolved phenotype of more teeth and an accelerated adult replacement rate, the timing of tooth number divergence and the spatial patterns of newly formed adult teeth are different in the two populations, suggesting distinct developmental mechanisms. Using genome-wide linkage mapping in marine-freshwater F2 genetic crosses, we find that the genetic basis of evolved tooth gain in the two freshwater populations is largely distinct. Together, our results support a model whereby increased tooth number and an accelerated tooth replacement rate have evolved convergently in two independently derived freshwater stickleback populations using largely distinct developmental and genetic mechanisms. PMID:26062935

  4. X-ray scattering study of hydrogen implantation in silicon

    SciTech Connect

    Sousbie, Nicolas; Capello, Luciana; Eymery, Joeel; Rieutord, Francois; Lagahe, Chrystelle

    2006-05-15

    The effect of hydrogen implantation in silicon single crystals is studied using high-resolution x-ray scattering. Large strains normal to the sample surface are evidenced after implantation. A simple and direct procedure to extract the strain profile from the scattering data is described. A comparison between different crystallographic orientation of the implanted silicon surface is then presented, namely, for <100>, <110>, and <111> orientations, showing a dependence that can be related to bond orientation. Effect of annealing on the stressed structure is finally described.

  5. Ion-implanted planar-buried-heterostructure diode laser

    DOEpatents

    Brennan, Thomas M. (Albuquerque, NM); Hammons, Burrell E. (Tijeras, NM); Myers, David R. (Albuquerque, NM); Vawter, Gregory A. (Albuquerque, NM)

    1991-01-01

    A Planar-Buried-Heterostructure, Graded-Index, Separate-Confinement-Heterostructure semiconductor diode laser 10 includes a single quantum well or multi-quantum well active stripe 12 disposed between a p-type compositionally graded Group III-V cladding layer 14 and an n-type compositionally graded Group III-V cladding layer 16. The laser 10 includes an ion implanted n-type region 28 within the p-type cladding layer 14 and further includes an ion implanted p-type region 26 within the n-type cladding layer 16. The ion implanted regions are disposed for defining a lateral extent of the active stripe.

  6. The lateral enamel lamina--component of tooth primordia in selected mammalian species.

    PubMed

    Witter, K; Matulová, P; Mísek, I

    2002-01-01

    The lateral enamel lamina (LEL) is a part of the enamel organ, which is probably not involved in tooth formation. It represents, besides the "stalk" of the tooth primordium, a second interconnection between enamel organ and oral epithelium or vestibular lamina. We detected the LEL in the sheep (Ovis aries), the dolphin (Stenella attenuata), and the vole (Microtus agrestis) by light microscopy and computer-aided three-dimensional reconstruction. The LEL could be found in cap to bell stage tooth primordia, most clearly in slowly developing tooth germs. LEL-like structures have been furthermore described or depicted in tooth germs of the mouse, the elk (Alces alces), the dugong (Dugong dugong), the elephant (Loxodonta africana), and the human. Probably it is a part of all mammalian tooth primordia that undergoes regression during morphogenesis of the enamel organ. As a reducing structure, it should be considered in studies of tooth development. PMID:12494916

  7. Autoinflation of saline-filled inflatable breast implants

    PubMed Central

    Peters, Walter

    2006-01-01

    Spontaneous autoinflation of saline-filled breast implants is a rare phenomenon; only 20 cases have been reported in the world literature. Over the past seven years, three patients have presented with significant unilateral autoinflation of their smooth, single-lumen, round, saline-filled implants. This developed at various times: progressively over 23 years with a Simaplast implant; between the ninth and 10th year after augmentation with a leaflet valve implant; and slowly over the first four years with a leaflet valve implant. The etiology of the autoinflation was shown to be different for the two types of implants. The Simaplast implant had likely been injected with a hypertonic filling solution – one that was twice as concentrated as ‘normal saline’. This would have created an osmotic gradient, which would have facilitated autoexpansion by diffusion. The implant solution remained clear and transparent. In addition, there were no detectable levels of glucose, uric acid or albumin in the fluid. By contrast, auto-inflation of the leaflet valve implants likely resulted from mechanical alterations of the valve mechanism. This type of implant is known to have a high deflation rate, with frequent partial deflations. It is interesting that one of the patients with the leaflet valve implants presented with an autoexpansion on one side and a partial deflation on the other side. Both implants were from the same lot number. The same mechanism that caused partial deflations may have also allowed fluid from the implant pocket to pass through the valve into the lumen of these implants. This could allow glucose, protein and cellular elements to enter into the lumen (these would not pass through an intact elastomeric shell) which would create an osmotic gradient, allowing water to enter the elastomeric shell by diffusion. The fluid in these leaflet valve implants was brownish yellow, very viscous and turbid. It contained elevated levels of glucose and uric acid which would not have passed through the elastomeric shell. Over the past 10 years, four different theories have been proposed in an attempt to explain the etiology of autoinflation. However, the findings of the present study indicate that there are only two mechanisms – a hypertonic filling solution and alterations of the valve mechanism. PMID:19554139

  8. Clinical study on the primary stability of two dental implant systems with resonance frequency analysis.

    PubMed

    Rabel, Annette; Köhler, Steffen Gerhard; Schmidt-Westhausen, Andrea Maria

    2007-09-01

    Primary stability has a major impact on the long-term success of dental implants. The aim of this study was to investigate the correlation of resonance frequency analysis (RFA) and insertion torque of self-tapping and non-self-tapping implants and their respective differences in primary stability. A group of 263 patients were treated with a total of 602 conically formed dental implants: 408 non-self-tapping Ankylos and 194 self-tapping Camlog. The maximum insertion torque during implant placement was recorded. Resonance frequency, measured as the implant stability quotient (ISQ), was assessed once immediately after insertion and twice 3 months later. Torque values of the non-self-tapping implants were significantly higher than those in the self-tapping group (p = 0.023). RFA did not show differences between the 2 groups (p = 0.956), but a correlation between ISQ values after implantation and 3 months after implant placement was measured (r = 0.712). Within the implant systems, no correlation between insertion torque and resonance frequency values could be determined (r = 0.305). Our study indicates that the ISQ values obtained from different implant systems are not comparable. The RFA does not appear suitable for the evaluation of implant stability when used as a single method. Higher insertion torque of the non-self-tapping implants appeared to confirm higher clinical primary stability. PMID:17401588

  9. The Biolink Implantable Telemetry System

    NASA Technical Reports Server (NTRS)

    Betancourt-Zamora, Rafael J.

    1999-01-01

    Most biotelemetry applications deal with the moderated data rates of biological signals. Few people have studied the problem of transcutaneous data transmission at the rates required by NASA's Life Sciences-Advanced BioTelemetry System (LS-ABTS). Implanted telemetry eliminate the problems associated with wire breaking the skin, and permits experiments with awake and unrestrained subjects. Our goal is to build a low-power 174-216MHz Radio Frequency (RF) transmitter suitable for short range biosensor and implantable use. The BioLink Implantable Telemetry System (BITS) is composed of three major units: an Analog Data Module (ADM), a Telemetry Transmitter Module (TTM), and a Command Receiver Module (CRM). BioLink incorporates novel low-power techniques to implement a monolithic digital RF transmitter operating at 100kbps, using quadrature phase shift keying (QPSK) modulation in the 174-216MHz ISM band. As the ADM will be specific for each application, we focused on solving the problems associated with a monolithic implementation of the TTM and CRM, and this is the emphasis of this report. A system architecture based on a Frequency-Locked Loop (FLL) Frequency Synthesizer is presented, and a novel differential frequency that eliminates the need for a frequency divider is also shown. A self sizing phase modulation scheme suitable for low power implementation was also developed. A full system-level simulation of the FLL was performed and loop filter parameters were determined. The implantable antenna has been designed, simulated and constructed. An implant package compatible with the ABTS requirements is also being proposed. Extensive work performed at 200MHz in 0.5um complementary metal oxide semiconductors (CMOS) showed the feasibility of integrating the RF transmitter circuits in a single chip. The Hajimiri phase noise model was used to optimize the Voltage Controlled Oscillator (VCO) for minimum power consumption. Two test chips were fabricated in a 0.5pm, 3V CMOS process. Measured phase noise for a 1.5mW, 200MHz ring oscillator VCO is -80dBc/Hz at 100KHZ offset, showing good agreement with the theory. We also propose a novel superregenerative receiver architecture for implementing the command receiver. The superregenerative receiver's simplicity, low cost, and low power consumption has made it the receiver of choice for short-distance data communications, remote control and home automation. We present the design of a superregenerative AM receiver implemented in a 0.5um CMOS technology that operates at 433.92MHz and dissipates only 300uW. Further work entails detailed transistor-level design of the FLL and superregenerative receiver and a monolithic implementation of an implantable transceiver in 0.5um CMOS technology.

  10. Immediate Implant-based Prepectoral Breast Reconstruction Using a Vertical Incision

    PubMed Central

    Lind, Jeffrey G.; Hopkins, Elizabeth G.

    2015-01-01

    Background: Ideally, breast reconstruction is performed at the time of mastectomy in a single stage with minimal scarring. However, postoperative complications with direct-to-implant subpectoral reconstruction remain significant. These include asymmetry, flap necrosis, animation deformity, and discomfort. We report on a series of patients who have undergone immediate single-stage prepectoral, implant-based breast reconstruction with a smooth, adjustable saline implant covered with mesh/acellular dermal matrix for support using a vertical mastectomy incision. This technique, when combined with an adjustable implant, addresses the complications related to subpectoral implant placement of traditional expanders. Our follow-up time, 4.6 years (55 months), shows a low risk of implant loss and elimination of animation deformity while also providing patients with a safe and aesthetically pleasing result. Methods: All patients who underwent immediate implant-based prepectoral breast reconstruction using a vertical mastectomy incision as a single-staged procedure were included. Charts were reviewed retrospectively. Adjustable smooth round saline implants and mesh/acellular dermal matrix were used for fixation in all cases. Results: Thirty-one patients (62 breasts) underwent single-staged implant-based prepectoral breast reconstruction using a vertical mastectomy incision. Postoperative complications occurred in 9 patients, 6 of which were resolved with postoperative intervention while only 2 cases resulted in implant loss. Conclusions: There can be significant morbidity associated with traditional subpectoral implant-based breast reconstruction. As an alternative, the results of this study show that an immediate single-stage prepectoral breast reconstruction with a smooth saline adjustable implant, using a vertical incision, in conjunction with mesh/matrix support can be performed with excellent aesthetic outcomes and minimal complications. PMID:26180713

  11. Indication of two Pacific walrus stocks from whole tooth elemental analysis

    USGS Publications Warehouse

    Jay, C.V.; Outridge, P.M.; Garlich-Miller, J. L.

    2008-01-01

    The Pacific walrus (Odobenus rosmarus divergens) is considered to be a single panmictic population for management purposes. However, studies on population structuring in this species are limited; in part, because portions of the population's range are often inaccessible. Therefore, alternative and complementary methods for investigating stock structure in the Pacific walrus are of particular interest. We used measures of elemental concentrations in whole tooth sections from ICP-MS in a discriminant analysis to investigate evidence of stock separation between walruses from two of three known breeding areas (S.E. Bering, St Lawrence, and Anadyr Gulf). Elemental compositions of teeth from female and male walruses from the S.E. Bering and St Lawrence breeding areas were significantly different, providing evidence of separate stocks. We also obtained insights into the potential relation of walruses from non-breeding areas to walruses from these breeding groups based on similarities in their dental elemental profiles. ?? 2008 Springer-Verlag.

  12. Dental Implant Complications.

    PubMed

    Liaw, Kevin; Delfini, Ronald H; Abrahams, James J

    2015-10-01

    Dental implants have increased in the last few decades thus increasing the number of complications. Since many of these complications are easily diagnosed on postsurgical images, it is important for radiologists to be familiar with them and to be able to recognize and diagnose them. Radiologists should also have a basic understanding of their treatment. In a pictorial fashion, this article will present the basic complications of dental implants which we have divided into three general categories: biomechanical overload, infection or inflammation, and other causes. Examples of implant fracture, loosening, infection, inflammation from subgingival cement, failure of bone and soft tissue preservation, injury to surround structures, and other complications will be discussed as well as their common imaging appearances and treatment. Lastly, we will review pertinent dental anatomy and important structures that are vital for radiologists to evaluate in postoperative oral cavity imaging. PMID:26589696

  13. Localization ability with bimodal hearing aids and bilateral cochlear implants

    NASA Astrophysics Data System (ADS)

    Seeber, Bernhard U.; Baumann, Uwe; Fastl, Hugo

    2004-09-01

    After successful cochlear implantation in one ear, some patients continue to use a hearing aid at the contralateral ear. They report an improved reception of speech, especially in noise, as well as a better perception of music when the hearing aid and cochlear implant are used in this bimodal combination. Some individuals in this bimodal patient group also report the impression of an improved localization ability. Similar experiences are reported by the group of bilateral cochlear implantees. In this study, a survey of 11 bimodally and 4 bilaterally equipped cochlear implant users was carried out to assess localization ability. Individuals in the bimodal implant group were all provided with the same type of hearing aid in the opposite ear, and subjects in the bilateral implant group used cochlear implants of the same manufacturer on each ear. Subjects adjusted the spot of a computer-controlled laser-pointer to the perceived direction of sound incidence in the frontal horizontal plane by rotating a trackball. Two subjects of the bimodal group who had substantial residual hearing showed localization ability in the bimodal configuration, whereas using each single device only the subject with better residual hearing was able to discriminate the side of sound origin. Five other subjects with more pronounced hearing loss displayed an ability for side discrimination through the use of bimodal aids, while four of them were already able to discriminate the side with a single device. Of the bilateral cochlear implant group one subject showed localization accuracy close to that of normal hearing subjects. This subject was also able to discriminate the side of sound origin using the first implanted device alone. The other three bilaterally equipped subjects showed limited localization ability using both devices. Among them one subject demonstrated a side-discrimination ability using only the first implanted device.

  14. Excimer laser interaction with dentin of the human tooth

    NASA Technical Reports Server (NTRS)

    Hammond, Ernest C., Jr.; Gilliam, Ruth L.; Baker, George R.

    1989-01-01

    The use an excimer laser produced many unusual conical structures within the dentin of the inner part of the human tooth. By varying the frequency of the laser one can disperse the energy and cause more bleeding in laser surgery, but not destroy the cells associated with the incision. Therefore, the healing process will virtually be without scarring. Whereas, using the infrared laser the blood loss would be less, but the healing process would tend to be longer because cells are being destroyed due to the cauterization effect of the laser. The question is, are these structures produced as an interaction with the laser or are they an intrinsic part of the structure. The effects of the laser interaction upon dentin was studied, and in using electron microscopy the interaction of the excimer laser upon the tooth dentin and other various biological tissue is more clearly understood.

  15. Beeswax as dental filling on a neolithic human tooth.

    PubMed

    Bernardini, Federico; Tuniz, Claudio; Coppa, Alfredo; Mancini, Lucia; Dreossi, Diego; Eichert, Diane; Turco, Gianluca; Biasotto, Matteo; Terrasi, Filippo; De Cesare, Nicola; Hua, Quan; Levchenko, Vladimir

    2012-01-01

    Evidence of prehistoric dentistry has been limited to a few cases, the most ancient dating back to the Neolithic. Here we report a 6500-year-old human mandible from Slovenia whose left canine crown bears the traces of a filling with beeswax. The use of different analytical techniques, including synchrotron radiation computed micro-tomography (micro-CT), Accelerator Mass Spectrometry (AMS) radiocarbon dating, Infrared (IR) Spectroscopy and Scanning Electron Microscopy (SEM), has shown that the exposed area of dentine resulting from occlusal wear and the upper part of a vertical crack affecting enamel and dentin tissues were filled with beeswax shortly before or after the individual's death. If the filling was done when the person was still alive, the intervention was likely aimed to relieve tooth sensitivity derived from either exposed dentine and/or the pain resulting from chewing on a cracked tooth: this would provide the earliest known direct evidence of therapeutic-palliative dental filling. PMID:23028670

  16. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Medrad utilized NASA's Apollo technology to develop a new device called the AID implantable automatic pulse generator which monitors the heart continuously, recognizes the onset of ventricular fibrillation and delivers a corrective electrical shock. AID pulse generator is, in effect, a miniaturized version of the defibrillator used by emergency squads and hospitals to restore rhythmic heartbeat after fibrillation, but has the unique advantage of being permanently available to the patient at risk. Once implanted, it needs no specially trained personnel or additional equipment. AID system consists of a microcomputer, a power source and two electrodes which sense heart activity.

  17. The Immediate Aesthetic and Functional Restoration of Maxillary Incisors Compromised by Periodontitis Using Short Implants with Single Crown Restorations: A Minimally Invasive Approach and Five-Year Follow-Up

    PubMed Central

    Marincola, Mauro; Lombardo, Giorgio; Pighi, Jacopo; Corrocher, Giovanni; Mascellaro, Anna; Lehrberg, Jeffrey; Nocini, Pier Francesco

    2015-01-01

    The functional and aesthetic restoration of teeth compromised due to aggressive periodontitis presents numerous challenges for the clinician. Horizontal bone loss and soft tissue destruction resulting from periodontitis can impede implant placement and the regeneration of an aesthetically pleasing gingival smile line, often requiring bone augmentation and mucogingival surgery, respectively. Conservative approaches to the treatment of aggressive periodontitis (i.e., treatments that use minimally invasive tools and techniques) have been purported to yield positive outcomes. Here, we report on the treatment and five-year follow-up of patient suffering from aggressive periodontitis using a minimally invasive surgical technique and implant system. By using the methods described herein, we were able to achieve the immediate aesthetic and functional restoration of the maxillary incisors in a case that would otherwise require bone augmentation and extensive mucogingival surgery. This technique represents a conservative and efficacious alternative to the aesthetic and functional replacement of teeth compromised due to aggressive periodontitis. PMID:26649207

  18. Towards Unraveling the Human Tooth Transcriptome: The Dentome

    PubMed Central

    2015-01-01

    The goal of the study was to characterize the transcriptome profiles of human ameloblasts and odontoblasts, evaluate molecular pathways and advance our knowledge of the human “dentome”. Laser capture microdissection was used to isolate odontoblasts and ameloblasts from human tooth buds (15-20week gestational age) from 4 fetuses. RNA was examined using Agilent 41k whole genome arrays at 2 different stages of enamel formation, presecretory and secretory. Probe detection was considered against the array negative control to control for background noise. Differential expression was examined using Significance Analysis of Microarrays (SAM) 4.0 between different cell types and developmental stages with a false discovery rate of 20%. Pathway analysis was conducted using Ingenuity Pathway Analysis software. We found that during primary tooth formation, odontoblasts expressed 14,802 genes, presecretory ameloblasts 15,179 genes and secretory ameloblasts 14,526 genes. Genes known to be active during tooth development for each cell type (eg COL1A1, AMELX) were shown to be expressed by our approach. Exploring further into the list of differentially expressed genes between the motile odontoblasts and non-motile presecretory ameloblasts we found several genes of interest that could be involved in cell movement (FN1, LUM, ASTN1). Furthermore, our analysis indicated that the Phospholipase C and ERK5 pathways, that are important for cell movement, were activated in the motile odontoblasts. In addition our pathway analysis identified WNT3A and TGFB1 as important upstream contributors. Recent studies implicate these genes in the development of Schimke immuno-osseous dysplasia. The utility of laser capture microdissection can be a valuable tool in the examination of specific tissues or cell populations present in human tooth buds. Advancing our knowledge of the human dentome and related molecular pathways provides new insights into the complex mechanisms regulating odontogenesis and biomineralization. This knowledge could prove useful in future studies of odontogenic related pathologies. PMID:25849153

  19. Towards unraveling the human tooth transcriptome: the dentome.

    PubMed

    Hu, Shijia; Parker, Joel; Wright, John Timothy

    2015-01-01

    The goal of the study was to characterize the transcriptome profiles of human ameloblasts and odontoblasts, evaluate molecular pathways and advance our knowledge of the human "dentome". Laser capture microdissection was used to isolate odontoblasts and ameloblasts from human tooth buds (15-20week gestational age) from 4 fetuses. RNA was examined using Agilent 41k whole genome arrays at 2 different stages of enamel formation, presecretory and secretory. Probe detection was considered against the array negative control to control for background noise. Differential expression was examined using Significance Analysis of Microarrays (SAM) 4.0 between different cell types and developmental stages with a false discovery rate of 20%. Pathway analysis was conducted using Ingenuity Pathway Analysis software. We found that during primary tooth formation, odontoblasts expressed 14,802 genes, presecretory ameloblasts 15,179 genes and secretory ameloblasts 14,526 genes. Genes known to be active during tooth development for each cell type (eg COL1A1, AMELX) were shown to be expressed by our approach. Exploring further into the list of differentially expressed genes between the motile odontoblasts and non-motile presecretory ameloblasts we found several genes of interest that could be involved in cell movement (FN1, LUM, ASTN1). Furthermore, our analysis indicated that the Phospholipase C and ERK5 pathways, that are important for cell movement, were activated in the motile odontoblasts. In addition our pathway analysis identified WNT3A and TGFB1 as important upstream contributors. Recent studies implicate these genes in the development of Schimke immuno-osseous dysplasia. The utility of laser capture microdissection can be a valuable tool in the examination of specific tissues or cell populations present in human tooth buds. Advancing our knowledge of the human dentome and related molecular pathways provides new insights into the complex mechanisms regulating odontogenesis and biomineralization. This knowledge could prove useful in future studies of odontogenic related pathologies. PMID:25849153

  20. Segmentation of tooth in CT images for the 3D reconstruction of teeth

    NASA Astrophysics Data System (ADS)

    Heo, Hoon; Chae, Ok-Sam

    2004-05-01

    In the dental field, the 3D tooth model in which each tooth can be manipulated individually is an essential component for the simulation of orthodontic surgery and treatment. To reconstruct such a tooth model from CT slices, we need to define the accurate boundary of each tooth from CT slices. However, the global threshold method, which is commonly used in most existing 3D reconstruction systems, is not effective for the tooth segmentation in the CT image. In tooth CT slices, some teeth touch with other teeth and some are located inside of alveolar bone whose intensity is similar to that of teeth. In this paper, we propose an image segmentation algorithm based on B-spline curve fitting to produce smooth tooth regions from such CT slices. The proposed algorithm prevents the malfitting problem of the B-spline algorithm by providing accurate initial tooth boundary for the fitting process. This paper proposes an optimal threshold scheme using the intensity and shape information passed by previous slice for the initial boundary generation and an efficient B-spline fitting method based on genetic algorithm. The test result shows that the proposed method detects contour of the individual tooth successfully and can produce a smooth and accurate 3D tooth model for the simulation of orthodontic surgery and treatment.

  1. Tooth loss patterns in older adults with special needs: a Minnesota cohort

    PubMed Central

    Chen, Xi; Clark, Jennifer J

    2011-01-01

    This study was conducted to detail tooth loss patterns in older adults with special needs. A total of 491 elderly subjects with special needs were retrospectively selected and followed during 10/1999-12/2006. Medical, dental, cognitive, and functional assessments were abstracted from dental records and used to predict risk of tooth loss. Tooth loss events were recorded for subjects during follow-up. Chi-squared tests were used to study the association between tooth loss and the selected risk factors. Logistic, poisson, and negative binomial regressions were developed to study tooth loss patterns. Overall, 27% of the subjects lost at least one tooth during follow-up. Fourteen subjects had tooth loss events per 100 person-years. Tooth loss pattern did not differ significantly among different special-needs subgroups (i.e. community-dwelling vs. long-term care, physically disabled vs. functionally independent). Special-needs subjects with three or more active dental conditions at arrival had more than twice the risk of losing teeth than those without any existing conditions. After adjusting other factors, the number of carious teeth or retained roots at arrival was a significant predictor of tooth loss for older adults with special needs (P=0.001). These findings indicate that appropriately managing active caries and associated conditions is important to prevent tooth loss for older adults with special needs. PMID:21449213

  2. Does tooth wear influence ageing? A comparative study across large herbivores.

    PubMed

    Gaillard, Jean-Michel; Berger, Vérane; Tidière, Morgane; Duncan, Patrick; Lemaître, Jean-François

    2015-11-01

    We test whether the intensity of tooth wear influences the strength of actuarial senescence across species of large herbivores. We collected from the literature data on tooth wear in the wild (measured as the slope of the regression of log-transformed M1 crown height on age), longevity (measured as the age at which 90% of individuals are dead) and two metrics of actuarial senescence in captive populations (rate of senescence between 6 and 12years of age and Gompertz rate of senescence). Between-species differences and variation in tooth height accounted for most of the observed variation in tooth wear among large herbivores: tooth height and tooth wear were positively correlated. In contrast, tooth wear was little influenced by sex, body mass, or taxonomy. No marked between-sex differences in longevity occurred. Males senesced faster than females when tooth wear was low (for both senescence metrics), while between-sex differences in actuarial senescence when tooth wear was high depended on the metric used to measure actuarial senescence. While longevity was mostly independent of the intensity of tooth wear, we found general support for a positive relationship between both measures of actuarial senescence and tooth wear. These patterns were consistent whether hypsodonty was controlled for or not. Although varying according to sex and to the metric used for assessing actuarial senescence, our findings suggest overall that tooth wear could be positively associated with actuarial senescence among large herbivores. Further longitudinal studies focusing on changes within individuals will be required to test whether a mechanistic link between tooth wear and actuarial senescence occurs in large herbivores. PMID:26368539

  3. Two-criteria dental aging method applied to a Bosnian population: comparison of formulae for each tooth group versus one formula for all teeth.

    PubMed

    Sarajli?, Nermin; Cihlarz, Zdenko; Klonowski, Eva-Elvira; Selak, Ivan; Brki?, Hrvoje; Topi?, Berislav

    2006-08-01

    The purpose of this study was to obtain age estimation formulae using the length of periodontosis, transparency of the root and root height in each tooth group for the current male population in Bosnia and Herzegovina and to compare these formulae with Lamendin's and Prince's formulae. The research was undertaken on 847 single rooted teeth from 200 identified deceased persons, individuals who died between the ages of 23 and 85 years. Periodontosis, transparency and root height were measured according to Lamendin's procedure. All teeth were grouped in two ways: according to the tooth groups and to the age groups. The highest coefficients of correlation are obtained for maxillary canines (R = 0,731) and mandibular canines (R = 0,706) and the maxillary lateral incisors showed the lowest mean error (ME = 6,63 years). In age groups, the lowest mean error was obtained in the 40-49 years age group (ME = 5,15 years). Equations developed in this study give statistically significantly better age estimations in comparison to the original Lamendin and Prince formulae for the whole sample as well as for each tooth group, except for mandibular central incisors. Age estimation with models developed for each tooth group (except for mandibular lateral incisors) was statistically significantly better than models based on the whole sample. PMID:16995854

  4. Equine Odontoclastic Tooth Resorption and Hypercementosis: Histopathologic Features.

    PubMed

    Smedley, R C; Earley, E T; Galloway, S S; Baratt, R M; Rawlinson, J E

    2015-09-01

    Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a painful progressive condition of older horses that involves multiple teeth, including canines and incisors. EOTRH is uncommonly recognized by veterinary pathologists and in some cases may be misdiagnosed as cementoblastoma. The cause is unknown. The goals of this study were to describe the histopathologic features of EOTRH in 17 affected horses from the United States and to increase awareness of this condition. Samples ranged from affected tooth to the entire rostral mandible and maxilla. Affected teeth exhibited cemental hyperplasia and lysis. The marked proliferation of cementum in severe cases caused bulbous enlargement of the intra-alveolar portions of affected teeth. Several teeth contained necrotic debris, bacteria, and plant material in the regions of cemental lysis. All horses exhibited dentinal lysis in at least affected tooth, and several contained necrotic debris in these regions. Endodontic disease was often present with inflammation, lysis, necrotic debris, fibrosis, and/or a thin rim of atubular mineralized tissue in the pulp cavity. Periodontal disease was a common feature that was primarily characterized by moderate lymphoplasmacytic inflammation. Resorption with secondary hypercementosis appears to begin on the external surface of the teeth rather than within the pulp cavity. Distinguishing EOTRH from other diseases requires a complete history that includes the number and location of affected teeth, a gross description of regional hard/soft tissue health, and radiographic findings. PMID:26077784

  5. Cracked tooth diagnosis and treatment: An alternative paradigm

    PubMed Central

    Mamoun, John S.; Napoletano, Donato

    2015-01-01

    This article reviews the diagnosis and treatment of cracked teeth, and explores common clinical examples of cracked teeth, such as cusp fractures, fractures into tooth furcations, and root fractures. This article provides alternative definitions of terms such as cracked teeth, complete and incomplete fractures and crack lines, and explores the scientific rationale for dental terminology commonly used to describe cracked teeth, such as cracked tooth syndrome, structural versus nonstructural cracks, and vertical, horizontal, and oblique fractures. The article explains the advantages of high magnification loupes (×6–8 or greater), or the surgical operating microscope, combined with co-axial or head-mounted illumination, when observing teeth for microscopic crack lines or enamel craze lines. The article explores what biomechanical factors help to facilitate the development of cracks in teeth, and under what circumstances a full coverage crown may be indicated for preventing further propagation of a fracture plane. Articles on cracked tooth phenomena were located via a PubMed search using a variety of keywords, and via selective hand-searching of citations contained within located articles. PMID:26038667

  6. An Nfic-hedgehog signaling cascade regulates tooth root development.

    PubMed

    Liu, Yang; Feng, Jifan; Li, Jingyuan; Zhao, Hu; Ho, Thach-Vu; Chai, Yang

    2015-10-01

    Coordination between the Hertwig's epithelial root sheath (HERS) and apical papilla (AP) is crucial for proper tooth root development. The hedgehog (Hh) signaling pathway and Nfic are both involved in tooth root development; however, their relationship has yet to be elucidated. Here, we establish a timecourse of mouse molar root development by histological staining of sections, and we demonstrate that Hh signaling is active before and during root development in the AP and HERS using Gli1 reporter mice. The proper pattern of Hh signaling activity in the AP is crucial for the proliferation of dental mesenchymal cells, because either inhibition with Hh inhibitors or constitutive activation of Hh signaling activity in transgenic mice leads to decreased proliferation in the AP and shorter roots. Moreover, Hh activity is elevated in Nfic(-/-) mice, a root defect model, whereas RNA sequencing and in situ hybridization show that the Hh attenuator Hhip is downregulated. ChIP and RNAscope analyses suggest that Nfic binds to the promoter region of Hhip. Treatment of Nfic(-/-) mice with Hh inhibitor partially restores cell proliferation, AP growth and root development. Taken together, our results demonstrate that an Nfic-Hhip-Hh signaling pathway is crucial for apical papilla growth and proper root formation. This discovery provides insight into the molecular mechanisms regulating tooth root development. PMID:26293299

  7. Tooth segmentation system with intelligent editing for cephalometric analysis

    NASA Astrophysics Data System (ADS)

    Chen, Shoupu

    2015-03-01

    Cephalometric analysis is the study of the dental and skeletal relationship in the head, and it is used as an assessment and planning tool for improved orthodontic treatment of a patient. Conventional cephalometric analysis identifies bony and soft-tissue landmarks in 2D cephalometric radiographs, in order to diagnose facial features and abnormalities prior to treatment, or to evaluate the progress of treatment. Recent studies in orthodontics indicate that there are persistent inaccuracies and inconsistencies in the results provided using conventional 2D cephalometric analysis. Obviously, plane geometry is inappropriate for analyzing anatomical volumes and their growth; only a 3D analysis is able to analyze the three-dimensional, anatomical maxillofacial complex, which requires computing inertia systems for individual or groups of digitally segmented teeth from an image volume of a patient's head. For the study of 3D cephalometric analysis, the current paper proposes a system for semi-automatically segmenting teeth from a cone beam computed tomography (CBCT) volume with two distinct features, including an intelligent user-input interface for automatic background seed generation, and a graphics processing unit (GPU) acceleration mechanism for three-dimensional GrowCut volume segmentation. Results show a satisfying average DICE score of 0.92, with the use of the proposed tooth segmentation system, by 15 novice users who segmented a randomly sampled tooth set. The average GrowCut processing time is around one second per tooth, excluding user interaction time.

  8. Ultrasonic scaler oscillations and tooth-surface defects.

    PubMed

    Lea, S C; Felver, B; Landini, G; Walmsley, A D

    2009-03-01

    Damage to tooth root surfaces may occur during ultrasonic cleaning with both piezoelectric and magnetostrictive ultrasonic scalers. It is unclear which mechanism causes more damage or how their mechanism of action leads to such damage. Our null hypothesis is that tooth-surface defect dimensions, resulting from instrumentation with ultrasonic scalers, are independent of whether the scaler probe is magnetostrictive or piezoelectric. Piezoelectric and magnetostrictive ultrasonic scaler probes were placed into contact against polished dentin samples (100 g/200 g). Resulting tooth surfaces were evaluated with a laser metrology system. Ultrasonic instrumentation produced an indentation directly related to the bodily movement of the probe as it made an impact on the surface. Load, generator power, and probe cross-section significantly affected probe vibration and defect depth/volume. Defect dimensions were independent of generator type. Magnetostrictive probes oscillated with greater displacement amplitudes than piezoelectric probes, but produced similar defects. This may be due to the cross-sectional shape of the probes. PMID:19329455

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

    PubMed

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

    2016-01-01

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

  10. Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

    PubMed Central

    Petersen, Richard C.

    2014-01-01

    The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC) solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo properties, electrical semiconductors, stress transfer, additives with low thermal PMC processing and new coating possibilities. PMID:25635227

  11. The Reverse Zygomatic Implant: A New Implant For Maxillofacial Reconstruction.

    PubMed

    Dawood, Andrew; Collier, Jonathan; Darwood, Alastair; Tanner, Susan

    2015-01-01

    This case report describes the rehabilitation of a patient who had been treated with a hemimaxillectomy, reconstruction with a latissimus dorsi vascularized free flap, and radiotherapy for carcinoma of the sinus some years previously. Limited jaw opening, difficult access through the flap to the bony site, and the very small amount of bone available in which to anchor the implant inspired the development and use of a new "reverse zygomatic" implant. For this treatment, site preparation and implant insertion were accomplished using an extraoral approach. The implant was used along with two other conventional zygomatic implants to provide support for a milled titanium bar and overdenture to rehabilitate the maxilla. Two years later, the patient continues to enjoy a healthy reconstruction. The reverse zygomatic implant appears to show promise as a useful addition to the implant armamentarium for the treatment of the patient undergoing maxillectomy. PMID:26574864

  12. Studying the issues in the additive manufacturing of dental implants by Electron Beam MeltingRTM (EBM)

    NASA Astrophysics Data System (ADS)

    Jamshidinia, Mahdi

    The ability of additive manufacturing (AM) processes to produce complex geometries is resulting in their rapid acceptance by a number of industries. This unique capability could be used for the optimization of the design of functional components that could find an application in different industries such as aerospace, automotive, energy, medical, and implants. However, there are still some challenges confronting this technology such as surface finish, residual stress, dimensional tolerance, processing speed, and anisotropy in microstructure and mechanical properties. Any of the mentioned issues could be influenced by the thermal history of a 3D printed component during the layer-by-layer manufacturing. Therefore, an understanding of the thermal cycling during the AM process is essential. In recent years, significant advances have been achieved in the design, manufacturing, and materials used for dental implants. However, there are still some differences between the natural tooth and a dental implant that might decrease patient satisfaction. One of the differences between the natural tooth and a dental implant is in its modulus of elasticity, which could result in an issue known as bone atrophy. The second important difference between a dental implant and a natural tooth is the fact that a natural tooth is surrounded by a periodontal ligament that allows the tooth to move in three directions. However, the periodontal ligament is destroyed during the extraction of a natural tooth. In the absence of the periodontal ligament, the biting force is directly transferred to the jawbone, resulting in discomfort for the patient. Also, the implant cannot be incorporated with the surrounding natural tooth and form a bridge. In this study, the application of a lattice structure for the manufacturing of a biocompatible dental implant is investigated. Three different lattice structures with different unit cell sizes were experimentally and numerically analyzed. The mechanical properties of lattice abutments in response to a static compression load were analyzed. However, the mechanical behavior of a structure could be considerably different under cyclic loads where fatigue failure could occur at stresses far below the static failure stress. Therefore, experimental and numerical analyses were performed in order to investigate the fatigue properties of the lattice dental abutment. Beside the design of a structure, some numerical models were developed to investigate the effects of Electron Beam MeltingRTM (EBM) process parameters on the heat distribution and the mentioned issues such as surface roughness and residual stress. A moving electron beam heat source and the temperature dependent properties of Ti-6Al- 4V were used in order to provide a 3D thermal-fluid flow model of EBMRTM, where the influence of process parameters as well as fluid convection on heat distribution were studied. Also, a coupled Computational Fluid Dynamic (CFD) - Finite Element Method (FEM) model was developed for studying the heat and thermal stress distribution in EBMRTM. The coupled CFD-FEM model combines the ability of CFD in considering the effects of fluid convection with the ability of FEM in calculating the thermal stress. The influences of the spacing distance between the Ti-6Al-4V plates produced by EBMRTM on the heat accumulation and the resultant surface roughness were investigated numerically and experimentally. An equation was derived from experimental data to predict the values of surface roughness as a function of the spacing distance. Finally, the influence of a novel design of heat sinks on the minimization of anisotropy was investigated, where the heat sinks were built in-situ during the EBMRTM process. Three sets of coupons with different numbers of heat sinks were designed and produced by EBMRTM. Another set of coupons was produced without a heat sink for comparison purposes. The results of the study could be used as the supportive experimental information required for the optimization of the support generation software in the powder-bed AM proc

  13. Implantable Impedance Plethysmography

    PubMed Central

    Theodor, Michael; Ruh, Dominic; Ocker, Martin; Spether, Dominik; Förster, Katharina; Heilmann, Claudia; Beyersdorf, Friedhelm; Manoli, Yiannos; Zappe, Hans; Seifert, Andreas

    2014-01-01

    We demonstrate by theory, as well as by ex vivo and in vivo measurements that impedance plethysmography, applied extravascularly directly on large arteries, is a viable method for monitoring various cardiovascular parameters, such as blood pressure, with high accuracy. The sensor is designed as an implant to monitor cardiac events and arteriosclerotic progression over the long term. PMID:25123467

  14. Allergy to Surgical Implants.

    PubMed

    Pacheco, Karin A

    2015-01-01

    Surgical implants have a wide array of therapeutic uses, most commonly in joint replacements, but also in repair of pes excavatum and spinal disorders, in cardiac devices (stents, patches, pacers, valves), in gynecological implants, and in dentistry. Many of the metals used are immunologically active, as are the methacrylates and epoxies used in conjunction with several of these devices. Allergic responses to surgical components can present atypically as failure of the device, with nonspecific symptoms of localized pain, swelling, warmth, loosening, instability, itching, or burning; localized rash is infrequent. Identification of the specific metal and cement components used in a particular implant can be difficult, but is crucial to guide testing and interpretation of results. Nickel, cobalt, and chromium remain the most common metals implicated in implant failure due to metal sensitization; methacrylate-based cements are also important contributors. This review will provide a guide on how to assess and interpret the clinical history, identify the components used in surgery, test for sensitization, and provide advice on possible solutions. Data on the pathways of metal-induced immune stimulation are included. In this setting, the allergist, the dermatologist, or both have the potential to significantly improve surgical outcomes and patient care. PMID:26362550

  15. Semiconductor Ion Implanters

    SciTech Connect

    MacKinnon, Barry A.; Ruffell, John P.

    2011-06-01

    In 1953 the Raytheon CK722 transistor was priced at $7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at $6.2 billion. Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing 'only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around $2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  16. Implantable electrical device

    NASA Technical Reports Server (NTRS)

    Jhabvala, M. D. (inventor)

    1982-01-01

    A fully implantable and self contained device is disclosed composed of a flexible electrode array for surrounding damaged nerves and a signal generator for driving the electrode array with periodic electrical impulses of nanoampere magnitude to induce regeneration of the damaged nerves.

  17. Implantable Drug Dispenser

    NASA Technical Reports Server (NTRS)

    Collins, E. R. J.

    1983-01-01

    Drugs such as insulin are injected as needed directly into bloodstream by compact implantable dispensing unit. Two vapor cavities produce opposing forces on drug-chamber diaphragm. Heaters in cavities allow control of direction and rate of motion of bellows. Dispensing capsule fitted with coil so batteries can be recharged by induction.

  18. Remote actuated valve implant

    DOEpatents

    McKnight, Timothy E; Johnson, Anthony; Moise, Jr., Kenneth J; Ericson, Milton Nance; Baba, Justin S; Wilgen, John B; Evans, III, Boyd McCutchen

    2014-02-25

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  19. Phosphoproteomes of Strongylocentrotus purpuratus shell and tooth matrix: identification of a major acidic sea urchin tooth phosphoprotein, phosphodontin

    PubMed Central

    2010-01-01

    Background Sea urchin is a major model organism for developmental biology and biomineralization research. However, identification of proteins involved in larval skeleton formation and mineralization processes in the embryo and adult, and the molecular characterization of such proteins, has just gained momentum with the sequencing of the Strongylocentrotus purpuratus genome and the introduction of high-throughput proteomics into the field. Results The present report contains the determination of test (shell) and tooth organic matrix phosphoproteomes. Altogether 34 phosphoproteins were identified in the biomineral organic matrices. Most phosphoproteins were specific for one compartment, only two were identified in both matrices. The sea urchin phosphoproteomes contained several obvious orthologs of mammalian proteins, such as a Src family tyrosine kinase, protein kinase C-delta 1, Dickkopf-1 and other signal transduction components, or nucleobindin. In most cases phosphorylation sites were conserved between sea urchin and mammalian proteins. However, the majority of phosphoproteins had no mammalian counterpart. The most interesting of the sea urchin-specific phosphoproteins, from the perspective of biomineralization research, was an abundant highly phosphorylated and very acidic tooth matrix protein composed of 35 very similar short sequence repeats, a predicted N-terminal secretion signal sequence, and an Asp-rich C-terminal motif, contained in [Glean3:18919]. Conclusions The 64 phosphorylation sites determined represent the most comprehensive list of experimentally identified sea urchin protein phosphorylation sites at present and are an important addition to the recently analyzed Strongylocentrotus purpuratus shell and tooth proteomes. The identified phosphoproteins included a major, highly phosphorylated protein, [Glean3:18919], for which we suggest the name phosphodontin. Although not sequence-related to such highly phosphorylated acidic mammalian dental phosphoproteins as phosphoryn or dentin matrix protein-1, phosphodontin may perform similar functions in the sea urchin tooth. More than half of the detected proteins were not previously identified at the protein level, thus confirming the existence of proteins only known as genomic sequences previously. PMID:20181113

  20. Rolling-Tooth Core Breakoff and Retention Mechanism

    NASA Technical Reports Server (NTRS)

    Badescu, Mircea; Bickler, Donald B.; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Hudson, Nicolas H.

    2011-01-01

    Sampling cores requires the controlled breakoff of the core at a known location with respect to the drill end. An additional problem is designing a mechanism that can be implemented at a small scale that is robust and versatile enough to be used for a variety of core samples. This design consists of a set of tubes (a drill tube and an inner tube) and a rolling element (rolling tooth). An additional tube can be used as a sample tube. The drill tube and the inner tube have longitudinal holes with the axes offset from the axis of each tube. The two eccentricities are equal. The inner tube fits inside the drill tube, and the sample tube fits inside the inner tube. While drilling, the two tubes are positioned relative to each other such that the sample tube is aligned with the drill tube axis and core. The drill tube includes teeth and flutes for cuttings removal. The inner tube includes, at the base, the rolling element implemented as a wheel on a shaft in an eccentric slot. An additional slot in the inner tube and a pin in the drill tube limit the relative motion of the two tubes. While drilling, the drill assembly rotates relative to the core and forces the rolling tooth to stay hidden in the slot along the inner tube wall. When the drilling depth has been reached, the drill bit assembly is rotated in the opposite direction, and the rolling tooth is engaged and penetrates into the core. Depending on the strength of the created core, the rolling tooth can score, lock the inner tube relative to the core, start the eccentric motion of the inner tube, and break the core. The tooth and the relative position of the two tubes can act as a core catcher or core-retention mechanism as well. The design was made to fit the core and hole parameters produced by an existing bit; the parts were fabricated and a series of demonstration tests were performed. This invention is potentially applicable to sample return and in situ missions to planets such as Mars and Venus, to moons such as Titan and Europa, and to comets. It is also applicable to terrestrial applications like forensic sampling and geological sampling in the field.