The aim of this in vitro study is to evaluate the stress distribution of different provisional materials designed with different connector dimensions using finite element analysis. Two adjacent prepped maxillary molars were designed digitally. Two-unit connected fixed dental prostheses (FDPs) were designed with four different connector dimensions (2 × 3, 3 × 3, 3 × 4, 4 × 4 mm (width × length)). The tested materials included polymethyl methacrylate (PMMA), bis-acrylate composite, and polyetheretherketone (PEEK). A total of 24 two-unit FDPs were tested using FEA in Autodesk Fusion 360. The study demonstrated a non-linear relationship between connector size and performance, with the 3 × 4 mm design exhibiting optimal stress distribution and the highest safety factors. Among materials, PMMA showed the greatest resistance to deformation, while PEEK provided the highest safety margins against yielding in optimal connectors. The 2 × 3 mm bis-acrylate composite configuration presented a critical failure risk, with stresses exceeding the material yield strength by 25-fold. Force angulation (0° vs. 10°) showed minimal effect on overall displacement patterns. Within the study limitations, the 3 × 4 mm connector demonstrated optimal performance across all materials. PEEK provided the highest safety factor in well-designed connectors, while bis-acrylate composite posed the greatest failure risk, particularly in smaller dimensions.
Alkhallagi et al. (Sun,) studied this question.