Evaluation of mandibular overdentures with different attachment systems: photoelastic analysis of stress distribution and effect of thermo-mechanical cycling.

Abstract

Considering the absence of data in literature about the fatigue of the attachment system generated by chewing function and the lack of consensus about the best treatment option for the longitudinal clinical success with implant supported overdentures, comparative data between the types of retention systems used in this jaw rehabilitation are necessary. The aim of the present study is to compare the stress distribution in jaw the retention force maintenance in overdentures using two types of attachment systems (bar clip, bar clip with distal ball/o' rings) retained for 2 or 3 implants. Photoelastic analysis (n=1) and simulation of chewing cycles (n=6) will be used. The groups will be divided in the following way: A - Overdenture on 2 implants with bar clip; B - Overdenture on 2 implants with bar clip and ball/o' Ring in the distal extension; C - Overdenture on 3 implants with bar clip; D - Overdenture on 3 implants with bar clip and ball/o' Ring in the distal extension. For the photoelastic stress analysis, an observer will evaluate the distribution of fringes around the implants and alveolar ridge under different conditions of load application. The results will be qualitatively compared. The results obtained in the simulation of chewing cycles will be tabulated and statistically analyzed.