Effect of different preparations and restorative materials on partial posterior restorations: A 3D FEA study using μCT data

Abstract

Statement of problem

Three-dimensional finite element analysis (3D FEA) allows for the accurate simulation of stress distribution and identification of potential failures in posterior indirect restorations. By combining microcomputed tomography (μCT) with FEA, more realistic and reliable models can be created, improving the accuracy of predictions.

Purpose

The purpose of this 3D FEA study using μCT data was to assess the effect of different restorative materials on stress distribution in partial posterior restorations and the resin cement layer.

Material and methods

Four replicas of a mandibular first molar were prepared for different partial posterior preparations: inlay, onlay, 1-piece endodontic crown, and occlusal veneer. For each model, monolithic posterior restorations were simulated with 4 different restorative materials: composite resin, lithium disilicate glass-ceramic, polymer-infiltrated ceramic, and zirconia. After the fabrication and luting of the restorations, μCT images of the specimens were obtained and 3D finite element models built. An evenly distributed load of 500 N was applied, simulating 3 occlusal contacts. The maximum value of maximum principal stress and stress distribution on the restorations, cement layers, and tooth structure was calculated and analyzed.

Results

One-piece endodontic crowns had lower stress, whereas inlays showed higher stress. Of the restorative materials, zirconia and glass-ceramic had the highest stress on the restorations, followed by polymer-infiltrated ceramic and composite resin. This difference between the restorative materials was larger for inlays and 1-piece endodontic crowns than for onlays and occlusal veneers. Cuspal coverage in the onlay preparation had lower and more evenly distributed stress than the intracoronal inlay preparation.

Conclusions

The different tooth preparations for single-unit posterior partial restorations influenced the stress distribution on the restoration, resin cement layer, and remaining tooth structure.