Finite Element Analysis of Occlusal Stress in Cervical Dentin: Effects of Thickness and Cross-Section Running title:Occlusal Stress in Cervical Dentin: Effects of Thickness and Cross-Section

Background & Objective: The cervical region of dentin plays a crucial role in the distribution of masticatory forces, with vertical root fractures often initiating and spreading from this area. This study investigates the distribution of occlusal stresses in the cervical region of root dentin, considering varying thicknesses and cross-sections, using Finite Element Analysis. Materials & Methods: Sections from central and premolar teeth were imported into CAD to create 3D models. The tooth structure and surrounding tissues were modeled using mechanical properties such as Young's modulus and Poisson's ratio. Four cross-sectional shapes—circular, oval, sand clock, and kidney—were designed. A force of 50 Newtons, representing the occlusal force of the opposing tooth, was applied to the palatal surface of the models at a 60° angle for anterior teeth and a 45° angle for premolars. The stress distribution in the cervical dentin was then analyzed. Results: Von Mises stress values indicated that stress points were highest in the kidney, sand clock, oval, and circular cross-sections, respectively. Increased thickness of the residual dentinal wall resulted in reduced maximum and minimum stress and a smaller area of stress regions. In all cross-sections, the minimum and maximum stress points were predominantly on the palatal and buccal sides of the cervical dentin, respectively. Conclusion: The study demonstrated that stress distribution in teeth varies with different root cross-sections, with higher stress observed in the sand clock and kidney cross-sections. Thinner dentin in the cervical region leads to greater stress concentration, especially in the buccal area of the tooth.