ABSTRACT
Introduction : The clinical survival of a dental implant is directly related to its biomechanical behavior. Since short implants present lower bone/implant contact area, their design may be more critical to stress distribution to surrounding tissues. Photoelastic analysis is a biomechanical method that uses either simple qualitative results or complex calculations for the acquisition of quantitative data. In order to simplify data acquisition, we performed a pilot study to demonstrate the investigation of biomechanics via correlation of the findings of colorimetric photoelastic analysis (stress transition areas; STAs) of design details between two types of short dental implants under axial loads. Methods Implants were embedded in a soft photoelastic resin and axially loaded with 10 and 20 N of force. Implant design features were correlated with the STAs (mm2) of the colored fringes of colorimetric photoelastic analysis. Results Under a 10 N load, the surface area of the implants was directly related to STA, whereas under a 20 N load, the surface area and thread height were inversely related to STA. Conclusion A smaller external thread height seemed to improve the biomechanical performance of the short implants investigated.
ABSTRACT
Objective: To demonstrate a colorimetric photoelastic analysis of tension distribution around dental implants under axial loads. Material and methods: Eight different designs of implant from two manufacturers were connected to their abutments, placed into epoxy resin blocks and observed under a polariscope coupled to a universal testing machine while subjected to axial loads of 5 N. The obtained images were quantitatively analyzed by image analysis software. Results: A strong correlation was found between the surface area and the implant fringe transition area (magenta color) of most samples (r = 0.908), and a moderate correlation was found between the fringe transition area and the mean thread height of the implants (r = 0.706, or r = 0.768 using a quadratic function). Conclusion: By this biomechanical study, it was possible to demonstrate a correlation of some implant characteristics to the colored fringe areas of tension distribution, a colorimetric method that can be used in comparative studies of photoelastic analysis. Clinical significance: An accurate planning and knowledge of oral implant biomechanics is important so that a safe and long-lasting treatment can be achieved. This biomechanical study presented some correlations of the implant features and its photoelastic behavior, information that could be used by the practitioner while choosing the implant design for each clinical situation.
ABSTRACT
As conchas de ostras podem se apresentar como fonte promissora na confecção de biomaterial para enxertia óssea, uma vez que apresentam, na sua constituição principal, o cálcio. Este trabalho teve por objetivo avaliar os efeitos de um biomaterial obtido a partir da concha da Crassostrea gigas na sua aplicação, em defeitos periodontais de ratos. Análise das partículas por MEV revelou tamanhos variados e superfície microporosa e, por EDXRF, demonstrou uma constituição básica de CaO. Dois grupos de vinte ratos receberam defeito periodontal, preenchidos com coágulo sanguíneo ou com biomaterial teste. Os tempos de monitoramento foram de 1, 3, 6 e 8 semanas. A análise histológica do biomaterial teste revelou: um processo inflamatório granulomatoso crônico; mais edema do que o controle; inicialmente, o aparecimento de um tecido osteoide mais fibroso, que resultou em um reparo ósseo em camadas finas, que, além de aspecto fibroplásico no ligamento periodontal, em estágio mais avançado, transformou-se em anquilose. Pode-se concluir que a aplicação do biomaterial no defeito periodontal deste trabalho não foi favorável.
Oyster shells may be presented as a potential source for the production of a bone graft biomaterial, once they are mainly constituted by calcium. The aim of this study was to evaluate the effects of a biomaterial based on Crassostrea gigas shell in the application of periodontal defects in rats.MEV analysis of the particles showed a variety of sizes and microporous surface, while EDXRF analysis demonstrated calcium oxide as the main component. Two groups of 20 WISTAR rats received periodontal defects filled with either blood clot or the test biomaterial. Monitoring periods were 1, 3, 6 and 8 weeks. Histological analysis revealed a chronic granulomatous process; more edema than control; an initial fibrous osteoid tissue; a thin layered bone repair; a fibroplasic aspect of the periodontal ligament; and in an advanced stage, ankylosis. It can be concluded that the application of the biomaterial in the periodontal defect of this study was unfavorable.