Effect of joint design and type of welding on the survival of misfit multiple prostheses

Abstract

This study will evaluate the effect of joint design and type of welding on the survival of misfit frameworks of multiple implantssuported prostheses casted in pure titanium. Forty frameworks will be casted in cp Ti. For each of them will be obtained an index with a standard marginal misfit. The frameworks will be sectioned and casted according to 2 designs of joints ("I" (I) and "X" (X)) and 2 welding type (TIG welding (TIG) and laser welding (L)), forming 4 groups: G1- I / SL; G2- X / SL; G3- I / TIG; G4- X / TIG. After welding the joints will be radiographed (90 KV, 15 mA, 0,6 s e 10 to 13 mm of distance), and the radiographies will be analyzed visually for the presence of pores inside the joint. There will de made the measurement of frameworks misfit using a measures microscope (120X) with 0.5 µm of precision after tightening one end screw with 10 Ncm of torque. After this procedure, it will be checked the misfit in the other pillars. This procedure will be done after the index confection before and after the welding procedure. It will be measured the stress generated in the implants in the same two moments. This analysis will be performed by electrical strain gauges positioned in the modified implants replica. It will be verified too, the stress patterns generated around the implants using photoelastic analysis. To analyze the longevity of the welded frameworks, they will be cycled (120 N, 1 Hz, 1.000.000 de cycles), to simulate one year of mastication. The data of misfit and stress values will be analyzed and the appropriate statistical test will be applied to compare the results. Then this data will be correlated. (AU)