INFLUENCE OF PROGRESSIVE VS. MINIMAL CANAL PREPARATIONS ON THE FRACTURE RESISTANCE OF MANDIBULAR MOLARS: A 3-DIMENSIONAL FINITE ELEMENT ANALYSIS.

ABSTRACT Introduction This study compared the residual tooth strength and stress distribution of a mandibular molar prepared with different variable tapered file systems using finite element analysis (FEA). Methods Two pre-accessed mandibular molar TruTeeth (Acadental Endo 3DP, Lenexa, KS) were subjected to simulated endodontic treatment in this study. One tooth was instrumented with ProTaper Gold (Dentsply, Tulsa, OK) and the other was instrumented with V-Taper 2H (SSWhite Dental, Lakewood, NJ). The two teeth were scanned using microcomputed tomography (micro-CT), and STL (stereolithography) surface meshes were developed for Finite Element Analysis (FEA). Each model was subjected to a 200-N multipoint load simulating mastication. The results of the FEA provided quantitative and qualitative measurements for Von Mises (VM) stress distribution and total deformation. Results The maximum von Mises (VM) stress was greater in the Pro-Taper Gold prepared model than the V-Taper 2H prepared model. In both models, total deformation values were highest in the clinical crown on the buccal aspect of the tooth. The highest stress values were found in the pericervical dentin, and stress decreased apically through the root. Conclusions Within the limitations of this study, it can be concluded that the maximum stress values within the tooth prepared by ProTaper Gold were higher than those in the tooth prepared by V-Taper 2H. Canal preparation with V-Taper 2H system preserves more pericervical dentin which may increase the resistance to fracture.