Shehabeldin Mohamed Saber1, Dennis Mohamed Hayaty2, Nawar Naguib Nawar3, Hyeon-Cheol Kim4. 1. Department of Endodontics, The British University, Cairo, Egypt; Department of Endodontics, Ain Shams University, Cairo, Egypt. Electronic address: Shehabeldin.saber@bue.edu.eg. 2. Department of Endodontics, Ain Shams University, Cairo, Egypt. 3. Department of Endodontics, The British University, Cairo, Egypt. 4. Department of Conservative Dentistry, Pusan National University School of Dentistry, Dental Research Institute, Yangsan, Korea. Electronic address: golddent@pusan.ac.kr.
Abstract
INTRODUCTION: This study aimed to compare the biomechanical properties of a mandibular first molar with different endodontic cavity designs and increasing sizes of root canal preparations using finite element analysis (FEA). METHODS: The experimental FE models were designed with three different endodontic access cavities and two sizes of canal preparations; traditional access cavity (TRD), conservative access cavity (CON), and truss access cavity (TUS), and #30/.04 and #40/.04 of root canal preparations. Vertical and oblique loads were applied with a 250 N static force to simulate masticatory forces. Mathematical analysis was done to evaluate the stress distribution patterns and maximum von Mises (VM) stresses was assessed at the occlusal surface, cervical line and 1-, 3-, 5-, and 7-mm from the root apices. RESULTS: Decreasing the size of the access cavity was associated with higher magnitude of cervical stresses. The magnitude of VM stresses was maximum at the 7-mm level and was minimum at the 1-mm level from the root apex. Increasing the size of the access cavity was associated with the transmission of stresses to a further apical direction regardless of the extent of root canal enlargement. The root canal enlargement from #30 to #40 increased radicular VM stresses within all models. CONCLUSION: Within the limitations of this study, CON and TUS access designs preserved a significant volume of tooth structure. The extent of root canal enlargement should be as small as practical without jeopardizing the biologic objectives of root canal treatment.
INTRODUCTION: This study aimed to compare the biomechanical properties of a mandibular first molar with different endodontic cavity designs and increasing sizes of root canal preparations using finite element analysis (FEA). METHODS: The experimental FE models were designed with three different endodontic access cavities and two sizes of canal preparations; traditional access cavity (TRD), conservative access cavity (CON), and truss access cavity (TUS), and #30/.04 and #40/.04 of root canal preparations. Vertical and oblique loads were applied with a 250 N static force to simulate masticatory forces. Mathematical analysis was done to evaluate the stress distribution patterns and maximum von Mises (VM) stresses was assessed at the occlusal surface, cervical line and 1-, 3-, 5-, and 7-mm from the root apices. RESULTS: Decreasing the size of the access cavity was associated with higher magnitude of cervical stresses. The magnitude of VM stresses was maximum at the 7-mm level and was minimum at the 1-mm level from the root apex. Increasing the size of the access cavity was associated with the transmission of stresses to a further apical direction regardless of the extent of root canal enlargement. The root canal enlargement from #30 to #40 increased radicular VM stresses within all models. CONCLUSION: Within the limitations of this study, CON and TUS access designs preserved a significant volume of tooth structure. The extent of root canal enlargement should be as small as practical without jeopardizing the biologic objectives of root canal treatment.