Biomechanical Properties of First Maxillary Molars with Different Endodontic Cavities: A Finite Element Analysis

Introduction: The aim of this study was to compare the biomechanical properties of first maxillary molars with different endodontic cavities using the finite element method. Methods: Three finite element analysis models of a maxillary first molar were designed and constructed with 3 different types of endodontic cavities: a traditional endodontic cavity, a conservative endodontic cavity, and an extended endodontic cavity. An intact tooth model was used for comparison. Each model was subjected to 3 different force loads directed at the occlusal surface. The stress distribution patterns and the maximum von Mises (VM) stresses were calculated and compared. Results: The peak VM stress on all models was at the site of the force load. The occlusal stresses were spread in an approximate actinomorphic pattern from the force loading point, and the stress was much higher when the force load was close to the access cavity margin. The peak root VM stresses on the root-filled teeth occurred at the apex and were significantly higher than that on the intact tooth, which appeared on the pericervical dentin. The area of pericervical dentin experiencing high VM stress increased as the cavities extended and the stress became concentrated in the area between the filling materials and the dentin. Conclusions: The stress distribution on the occlusal surface were similar between the conservative endodontic cavity, the traditional endodontic cavity, and the extended endodontic cavity. With enlargement of the access cavity, the stress on the pericervical dentin increases dramatically.