Biomechanical analysis of new constructions of adhesive bridge prostheses

Abstract

The purpose of the study was a numerical analysis of the stress-strain state of novel designs of fixed adhesive dental bridges made of polymethylmethacrylate (PMMA) to replace the missing second premolar of the mandible with first premolar and molar as abutments. Three-dimensional models of dental bridges (with the traditional (vertical) (T) insertion direction, as well as those developed with the vestibulo-oral (VO) insertion direction and the oral-vestibular (OV) insertion direction) were obtained by scanning with 3D scanner S600 ARI (ZirkonZahn GmbH) and subsequent processing in the Modellier program (ZirkonZahn GmbH). To evaluate the stress-strain state of the adhesive dental bridges, the ANSYS FEM software was used. 100 N force acting in the oral-vestibular direction was applied at various angles to the nodes localized in the areas of enamel ridges to simulate the occlusal contacts of antagonistic teeth. It was established that the direction of the occlusal force vector has a significant effect on the values of equivalent (von Mises) stresses and displacements in the dental bridge. It was shown that the lowest displacements and stresses occurred in the type (T) adhesive bridge, while the highest displacements and stresses occurred in the type (OV) over the entire range of the load angle variation. An increase in the elastic modulus of the bridge material leads to a decrease in maximum displacements, while the stresses in the prosthesis change very slightly. The numerical calculation showed that the PMMA-manufactured dental bridges’ durability equals to 233 days for (OV), 780 days for (VO) and 1458 days for (T) with an average chewing load of 100 N, which indicates the possibility of using these novel designs as temporary dental bridges.