Análise das tensões em próteses implantossuportadas esplintadas, variando o tipo de conexão protética e a inclinação do implante: estudo pelo método dos elementos finitos tridimensionais não linear

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genotoxicity of corrosion eluates obtained from endosseous implants

Purpose: Commercially pure titanium alloys are currently used as metallic biomaterials in implantology. Corrosion phenomena appear to play a decisive role in metallic implant long-term behavior. Thus, the goal of this study was to examine the genotoxic potential of corrosion eluates obtained from dental implants using Chinese ovary hamster cells in vitro by the single-cell gel (comet) assay. This technique detects deoxyribonucleic acid strand breaks in individual cells in alkaline conditions.Materials and Methods: the materials tested included 3 dental implants commercially available. Each of the tested materials was corroded in a solution consisting of equal amounts of acetic acid and sodium chloride (0.1 M) for 1, 3, 7, 14, and 21 days. The Chinese ovary hamster cultures were then exposed to all corrosion eluates obtained from endosseous dental implants for 30 minutes at 37 degrees C.Results: None of the eluates was found to exhibit genotoxicity, regardless of the type of dental implant used.Conclusion: the results suggest that all dental implants tested in this study did not induce deoxyribonucleic acid breakage as depicted by the single-cell gel (comet) assay.

Evaluation of Torque Maintenance of Abutment and Cylinder Screws With Morse Taper Implants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bone Spreading and Standardized Dilation of Horizontally Resorbed Bone: Technical Considerations

The uses of a new bone spreading technique with simultaneous implant placement are discussed. The spreading system is an alternative technique to Summers' osteotome. Specific screw designs (spreader) served to laterally compress the bone to increase the cancellous density adjacent to the site. The spreader achieved a controlled and standardized dilation of horizontal bone. The advantages, material selection, and the application of this new procedure are detailed. (Implant Dent 2009; 18:119-125)

Rehabilitation of Atrophic Maxilla Using the Combination of Autogenous and Allogeneic Bone Grafts Followed by Protocol-Type Prosthesis

Currently, there are several techniques for the rehabilitation of atrophic maxillary ridges in literature. The grafting procedure using autogenous bone is considered ideal by many researchers, as it shows osteogenic capability and causes no antigenic reaction. However, this type of bone graft has some shortcomings, mainly the restricted availability of donor sites. In recent years, several alternatives have been investigated to supply the disadvantages of autogenous bone grafts. In such studies, allogeneic bone grafts, which are obtained from individuals with different genetic load, but from the same species, have been extensively used. They can be indicated in cases of arthroplasty, surgical knee reconstruction, large bone defects, and in oral and maxillofacial reconstruction. Besides showing great applicability and biocompatibility, this type of bone is available in unlimited quantities. on the other hand, allogeneic bone may have the disadvantage of transmitting infectious diseases. Atrophic maxillae can be treated with bone grafts followed by osseointegrated implants to obtain aesthetic and functional oral rehabilitation. This study aimed to show the viability of allogeneic bone grafting in an atrophic maxilla, followed by oral rehabilitation with dental implant and protocol-type prosthesis within a 3-year follow-up period by means of a clinical case report.

Authorship, Collaboration, and Funding Trends in Implantology Literature: Analysis of Five Journals From 2005 to 2009

Purpose: To identify the trend of authorship in dental implant by exploring the prevalence of coauthored articles and to investigate the collaboration efforts, trends in funding involved in original articles, and their relationships. Materials: Articles published in the Clinical Oral Implants Research, International Journal of Oral & Maxillofacial Implants, Clinical Implant Dentistry and Related Research, Implant Dentistry, and Journal of Oral Implantology from 2005 to 2009 were reviewed. Nonoriginal articles were excluded. For each included articles, number of authors, collaboration efforts, and extramural funding were recorded. Descriptive and analytical statistics (alpha = 0.05), including logistic regression analysis and chi(2) test, were used. Results: From a total of 2085 articles, 1503 met the inclusion criteria. Publications with 5 or more authors increased over time (P = 0.813). The amount of collaboration among different disciplines, institutions, and countries all increased. The greatest increase of collaboration was seen among institutions (P = 0.09). Non-funding studies decreased over time (P = 0.031). There was a strong association between collaboration and funding for the manuscripts during the years studied (OR, 1.5). Conclusion: The number of authors per articles and collaborative studies increased over time in implant-related journals. Collaborative studies were more likely to be funded. (Implant Dent 2011;20:68-75)

Desenvolvimento de um torquímetro de precisão para o estudo do desempenho de implantes osseointegrados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of a Fluoridated Medium with Different pHs on Commercially Pure Titanium-Based Implants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Argon-based atmospheric pressure plasma enhances early bone response to rough titanium surfaces

This study investigated the effect of an Argon-based atmospheric pressure plasma (APP) surface treatment operated chairside at atmospheric pressure conditions applied immediately prior to dental implant placement in a canine model. Surfaces investigated comprised: rough titanium surface (Ti) and rough titanium surface + Argon-based APP (Ti-Plasma). Surface energy was characterized by the Owens-Wendt-Rabel-Kaelble method and chemistry by X-ray photoelectron spectroscopy (XPS). Six adult beagles dogs received two plateau-root form implants (n = 1 each surface) in each radii, providing implants that remained 1 and 3 weeks in vivo. Histometric parameters assessed were bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Statistical analysis was performed by Kruskall-Wallis (95% level of significance) and Dunn's post-hoc test. The XPS analysis showed peaks of Ti, C, and O for the Ti and Ti- Plasma surfaces. Both surfaces presented carbon primarily as hydrocarbon (C?C, C?H) with lower levels of oxidized carbon forms. The Ti-Plasma presented large increase in the Ti (+11%) and O (+16%) elements for the Ti- Plasma group along with a decrease of 23% in surface-adsorbed C content. At 1 week no difference was found in histometric parameters between groups. At 3 weeks significantly higher BIC (>300%) and mean BAFO (>30%) were observed for Ti-Plasma treated surfaces. From a morphologic standpoint, improved interaction between connective tissue was observed at 1 week, likely leading to more uniform and higher bone formation at 3 weeks for the Ti-Plasma treated implants was observed. (C) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 2012.

Effects of laser-weld joint opening size on fatigue strength of Ti-6Al-4V structures with several diameters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fatigue strength: effect of welding type and joint design executed in Ti-6Al-4V structures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Negative Effects of Alcohol Intake and Estrogen Deficiency Combination on Osseointegration in a Rat Model

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Screw Spreading: Technical Considerations and Case Report

The spreading system is an alternative technique to the Summers osteotome. The crest expansion technique is a less invasive procedure in which the facial wall expands after the medullary bone is compressed against the cortical wall. It improves the density of the maxillary bone, which allows for greater initial stability of implants. A specific screw instrument, the "spreader," achieved a controlled and standardized dilation of the bone horizontally. The use of spreaders to enhance the dental implant site is a highly predictable procedure. (Int J Periodontics Restorative Dent 2011;31:141-147.)

Histomorphometrical analysis of bone formed after maxillary sinus floor augmentation by grafting with a combination of autogenous bone and demineralized freeze-dried bone allograft or hydroxyapatite

Background: Maxillary sinus floor augmentation procedures are currently the treatment of choice when the alveolar crest of the posterior maxilla is insufficient for dental implant anchorage. This procedure aims to obtain enough bone with biomaterial association with the autogenous bone graft to create volume and allow osteo conduction. The objective of this study was to histologically and histometrically evaluate the bone formed after maxillary sinus floor augmentation by grafting with a combination of autogenous bone, from the symphyseal area mixed with DFDBA or hydroxyapatite.Methods: Ten biopsies were taken from 10 patients 10 months after sinus floor augmentation using a combination of 50% autogenous bone plus 50% dernineralized freeze-dried bone allograft (DFDBA group) or 50% autogenous bone plus 50% hydroxyapatite (HA group). Routine histological processing and staining with hernatoxylin and eosin and Masson's trichrome were performed.Results: the histomorphometrical analysis indicated good regenerative results in both groups for the bone tissue mean in the grafted area (50.46 +/- 16.29% for the DFDBA group and 46.79 +/- 8.56% for the HA group). Histological evaluation revealed the presence of mature bone with compact and cancellous areas in both groups. The inflammatory infiltrate was on average nonsignificant and of mononuclear prevalence. Some biopsies showed blocks of the biomaterial in the medullary spaces close to the bone wall, with absence of osteogenic activity.Conclusions: the results indicated that both DFDBA and HA associated with an autogenous bone graft were biocompatible and promoted osteoconduction, acting as a matrix for bone formation. However, both materials were still present after 10 months.

Treatment of ligature-induced peri-implantitis by lethal photosensitization and guided bone regeneration: A preliminary histologic study in dogs

Background: the purpose of this pilot study was to evaluate the healing potential and reosseointegration in ligature-induced peri-implantitis defects adjacent to various dental implant surfaces following lethal photosensitization.Methods: A total of 36 dental implants with 4 different surface coatings (9 commercially pure titanium surface [CPTi]; 9 titanium plasma-sprayed [TPS]; 9 hydroxyapatite [HA]; and 9 acid-etched [AE]) were inserted in 6 male mongrel dogs 3 months after extraction of mandibular premolars. After a 2-month period of ligature-induced peri-implantitis and 12 months of natural peri-implantitis progression, only 19 dental implants remained. The dogs underwent surgical debridement of the remaining dental implant sites and lethal photosensitization by combination of toluidine blue O (100 mug/ml) and irradiation with diode laser. All exposed dental implant surfaces and bone craters were meticulously cleaned by mechanical means, submitted to photodynamic therapy, and guided bone regeneration (GBR) using expanded polytetrafluoroethylene (ePTFE) membranes. Five months later, biopsies of the implant sites were dissected and prepared for ground sectioning and analysis.Results: the percentage of bone fill was HA: 48.28 +/- 15.00; TPS: 39.54 +/- 12.34; AE: 26.88 +/- 22.16; and CPTi: 26.70 +/- 16.50. The percentage of reosseointegration was TPS: 25.25 +/- 11.96; CPTi: 24.91 +/- 17.78; AE: 17.30 +/- 15.41; and HA: 15.83 +/- 9.64.Conclusion: These data suggest that lethal photosensitization may have potential in the treatment of peri-implantitis.