Influência do torque, previamente à soldagem a laser, no ajuste vertical de infra-estruturas metálicas sobre implantes

Abstract

This study evaluated the influence of the torque given to the screws of the abutments on replicas of implants in working cast previously the laser welding procedures. From a master model with 4 implants with external hexagon was made a working cast. For the confection of metallic framework, abutments and pre-fabricated cylindrical bars of titanium had been used, which had been joined by means of laser welding to compose three groups: GS/T - group without torque, GT10 - group torque of 10 Ncm and GT20 - group torque of 20 Ncm. Before the weldings, the torque applied in the screws of group GS/T was only manual, without the use of torquemeter, and in groups GT10 and GT20 the abutment screws had received torque of 10 and 20 Ncm, respectively. After the weldings the abutment/implant interfaces in the vertical axle (y) had been evaluated in comparing optical microscope under magnification of 40 times. The readings had been made by means of two different methodologies. First the test of the only screw was used (TPU), in which evaluated the interfaces of screwed and not screwed abutments, considering only the extremities abutments of the frameworks. Later the interfaces of all abutments had been evaluated when these were screwed with torque of 20 Ncm. The data had been submitted to statistical analyses (P<.05). In the TPU, the intergroups analysis (Kruskal Wallis) did not show statistically significant difference for no condition of tightening, screwed and not screwed abutments, in other words, the torques of 10 Ncm and 20 Ncm pre-welding in groups GT10 and GT20 did not guarantee minors distortions of frameworks; the intragroups analysis (Wilcoxon) showed that for all the groups the interfaces of not screwed abutments had been statistically higher that the interfaces of the screwed abutments, in other words, had evidenced distortions in all frameworks after the weldings. The analysis of variance test (ANOVA) was applied for the comparisons of the interfaces when all abutments were screwed and did not have statistically significant difference between the groups (P=.686). The pre-welding torque in the abutments screws did not influence in the quality of adaptation of prosthetic frameworks over implants.