Strength analysis of a three-unit dental bridge framework with the Finite Element Method.

Purpose: The aim of the study was to analyse the strength of a prosthetic bridge with variable geometry in the connectors between the span and the retention elements on the pillar teeth crowns.

Methods: Research was carried using the Finite Elements Method (FEM) on a model of the bridge in the anterior teeth arch in the field 21-22-23, obtained using a contact scanner and computer aided design (CAD) system, with four different cross-sectional areas of the connectors: 4.0, 5.0, 5.5, and 6.0 mm2. For that purpose, the impact of the properties of selected metal alloys on the deflection of the prosthesis was analysed.

Results: On the basis of the analyses, it was found that when the loading force acted obliquely, the stress was 19% higher compared to the stress with a loading vertical force. In the case of connectors with the smallest cross-sectional area, the stress exceeded permissible value (with safety factor n = 2) for one of the alloys.

Conclusions: Deflection of the bridges tested changed depending on the connector cross-section and the elastic modulus of the selected material.