ABSTRACT
Acetalic resin, or polyoxymethylene (POM), is an alternative material to metal for the manufacturing of bars for implant-supported overdentures. The objective of this work is to study the distribution of von Mises equivalent stresses, equivalent deformations and total displacements when a force is applied on acetalic resin bars with different thicknesses and distal extensions (cantilever) lengths, using the Finite Element Method (FEM). Two Definifit® (Gt-Medical) bars were reproduced virtually in Exocad DentalCAD®, and distal extensions were added. The numerical analysis of the structures was performed using the academic program FEMAS (cmech.webs.com). A vertical force of 1N was applied over the entire bar and, over the abutments, the anterior and lateral arches, and the distal extensions. In both bars, the values of stress, deformation and displacement increase with the length of the distal extension. Bar thickness and cantilever length appear to influence the stress on both acetalic resin bars.
