Avaliação de desajuste vertical de infraestruturas protéticas sobre implantes confeccionadas em liga de Co-Cr e soldagem TIG

Abstract

The vertical misfit of metal infrastructures – distance between the base of the cylinder and implant platform – can have an impact on biomechanical failures, especially after casting and/or welding processes. Thus, the aim of this study was to evaluate quantitatively the vertical misfit of implant prosthetic infrastructures made in Co-Cr alloys before and after TIG welding. Thirty infrastructures - composed of two prosthetic cylinders - of cobalt-chromium alloys (Co-Cr) were divided into 3 groups (n = 10): control group (GC), with pre-made cylinders, with 0.85 mm thickness; test groups: G1.5 and G2, with cylinders 1.5 and 2.0 mm thickness, respectively. Rectified the cylinders of test groups and then took all 30 infrastructures in scanning electron microscope (SEM) to measure the vertical misfits before soldering. Afterward, were to execute the TIG welding and again the infrastructures were taken to SEM. Data were analyzed by the Shapiro-Wilk test, Mann-Whitney test, Wilcoxon test and T-test, considering significant p<.05 values. The results showed statistically significant difference between GC and test groups (p<.001) but not between test groups (p=199) before to welding. The analysis between the groups before and after welding, there was statistically significant difference for GC (p<.001), but not for G1.5 (p=1.000) and G2 (p=.570). Finally, there was no statistically significant difference between GC and G1.5 (p=.525), or between G1.5 and G2 (p=.102), but there was difference between GC and G2 (p<.006) after welding. Therefore, within the limitations of this study, was concluded that casting and welding processes had a negative influence on the values of vertical misfits.