Photoelastic stress analysis of splinted and unitary implant-supported prostheses

The aim of this study was to evaluate the effects that splinting and different lengths of implants have on the stress distribution in implant-supported prostheses by photoelastic analysis. A total of five photoelastic resin models were made with different proposed situations, and 400 load applications were performed for the analysis. Compared with the unitary prosthesis, the splinted implant-supported prosthesis acted favorably in the distribution of stresses and strains to the implant (p < 0.001). The increase in length was a significant factor in the stress distribution (p < 0.05) and, ultimately, the overall reduction in stress. It was concluded that the splinted implant-supported prosthesis behaved better biomechanically compared with the unitary prosthesis.

Stress analysis in oral obturator prostheses, part II: photoelastic imaging

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stress distribution around osseointegrated implants with different internal-cone connections: photoelastic and finite element analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Photoelastic stress analysis in prosthetic implants of different diameters: mini, narrow, standard or wide

This study investigated the biomechanical behavior of screwed partial fixed prosthesis supported by implants with different diameters (2.5 mm; 3.3 mm and 3.75 mm) by using a photoelastic analysis. Six photoelastic models were fabricated in PL-2 resin as single crowns or splinted 3-unit piece. Models were positioned in a circular polariscope and 100-N axial and oblique (45 degrees) loads were applied in the occlusal surface of the crowns by using a universal testing machine (EMIC). The stresses were photographically recorded and qualitatively analyzed using a software (Adobe Photoshop). Under axial loading, the number of fringes was inversely proportional to the diameter of the implants in the single crown models. In the splinted 3-unit piece, the 3.75-mm implant promoted lower number of fringes regardless of loading area application. Under oblique loading, a slight increase of fringes number was observed for all groups. The standard implant diameter promoted better stress distribution than the narrow and mini diameter implants. Additionally, the splinted crowns showed a more uniform stress distribution.

Influence of morphological variables in photoelastic models with implants submitted to axial loading

Purpose: This study used 12 photoelastics models with different height and thickness to evaluate if the axial loading of 100N on implants changes the morphology of the photoelastic reflection. Methods: For the photoelastic analysis, the models were placed in a reflection polariscope for observation of the isochromatic fringes patterns. The formation of these fringes resulted from an axial load of 100N applied to the midpoint of the healing abutment attached to the implant with 10.0mm x 3.75mm (Conexão, Sistemas de Próteses, Brazil). The tension in each photoelastic model was monitored, photographed and observed using the software Phothoshop 7.0. For qualitative analysis, the area under the implant apex was measured including the green band of the second order fringe of each model using the software Image Tool. After comparison of the areas, the performance generated by each specimen was defined regarding the axial loading. Results: There were alterations in area with different height and thickness of the photoelastic models. It was observed that the group III (30mm in height) presented the smallest area. Conclusion: There was variation in the size of the areas analyzed for different height and thickness of the models and the morphology of the replica may directly influence the result in researches with photoelastic models.