Evaluation between different systems of connections in the biomechanics of implant-supported fixed prosthesis of three elements when subjected to axial and oblique loads through photoelastic and extensometric analysis
The evolution of morse taper connection had the remarkable step development of new designs for the connection. Currently, there are models of abutments morse taper on the market that may have various configurations. It is fundamental the acquaintance of each of these models, it's effect on the stress transmission and the interaction between them, to optimize the distribution of masticatory force, by means of these prostheses and implants and to bone support. Thus, this study aims to assess, through photoelastic and extensometric analysis, biomechanical behavior of implant dentures 3 elements with different types of connections: external hexagon (EH), morse taper (MT), internal morse hexagon (IMH), morse taper hexagon (MTH) and frictional morse taper (FMT) and different types of occlusal loads (axial and oblique). The specimens will be divided into 05 groups of 01 specimen each for photoelastic analysis and five groups of 05 specimens each for extensometric analysis. Thirty models will be made, these will be 5 of photoelastic resin (PL-2) and 25 of polyurethane (F160). For each group will be a prosthesis made of 3 elements on 2 implants of 11,5x4 mm (Osteofit). In the test of photoelasticity, a photoelastic model set / implant / prosthesis is positioned in a circular polariscope, and then loads are applied of 100 N, axial and oblique direction (45 °), in fixed points of the occlusal surface of the prosthetic crown with help of a universal testing machine (EMIC). The generated stress are photographically recorded and analyzed in graphic software (Adobe Photoshop) to check the direction of propagation and intensity of the stresses, according to the qualitative analysis. For the methodology of extensometer, two resistance strain gages are positioned horizontally on the mesial and distal region of the implants directly on the marginal ridge of polyurethane models. The electrical signals will be captured by a data acquisition unit controlled by a computer, are processed by a specific software. Each test will be performed 5 times and the recorded stress values, and for each trial are expected to stress values reset to verify the absence of plastic deformation. Mean registered stress values will be grouped into tables and subjected to statistical analysis.
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