Biomechanical analysis of new constructions of adhesive bridge prostheses

The purpose of the study was a numerical analysis of the stress-strain state of new designs of fixed adhesive bridges made of polymethylmethacrylate to replace the missing second premolar of the lower jaw based on the first premolar and first molar. Three-dimensional models of prostheses (with the traditional (T) route of administration, as well as those developed with the vestibulo-oral (VO) route of administration and the oral-vestibular (OV) route of administration) were obtained by scanning in a 3D scanner S 600 ARI ( ZirkonZahn GmbH ) and subsequent processing in the Modellier program ( ZirkonZahn GmbH ). To determine the stress-strain state of the adhesive bridge, the ANSYS finite element modelling package was used. The load acting in the oral-vestibular direction and equal to 100 N was applied at different 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 significantly affects the values of equivalent (according to Mises) stresses and displacements in the adhesive bridge. It was shown that the smallest displacements and stresses occurred in the type (T) adhesive bridge, while the displacements and stresses in the adhesive bridge type (OV) took the greatest values over the entire range of the load angle. An increase in the elastic modulus of the first kind (Young’s) modulus of the structural material of the prosthesis leads to a decrease in maximum displacements, while the stresses in the prosthesis change very slightly. The calculation showed that the durability of the structures of the adhesive bridge of polymethyl methacrylate is 233 days (OV), 780 days (VO) and 1458 days (T) with an average chewing load of 100 N, which indicates the possibility of using these prostheses as preliminary (temporary).