Biomechanical properties of mandibular first molar with truss and conventional access cavities: A finite element analysis

Aim: The aim of this study was to compare the biomechanical strength properties of the mandibular first molar with truss and conventional endodontic access cavities using the finite element method. Methods: Two finite element analysis (FEA) models of a mandibular first molar were designed and constructed with truss endodontic cavity (TREC) and Conventional endodontic cavity (CEC). Each model was subjected to three different force loads directed at the occlusal surface. The stress distribution patterns and the maximum von Mises (VM) stresses were calculated and compared. FEM software ANSYS was used for evaluation. Results: The peak VM stress on both models was at the site of the force load. The occlusal stresses were spread in an approximate actinomorphic pattern from where the force was loaded, 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 cavity size increased and became concentrated in the area between the filling materials and the dentin. Conclusion: Under all loading conditions, the TREC model showed low-stress concentration compared to the CEC model. With enlargement of the access cavity, the stress on the pericervical dentin increased significantly.