Biomechanical stress analysis of ceramic and indirect hybrid composite endocrowns: A three-dimensional finite element analysis

Aim: The purpose of this study was to compare equivalent stresses in mandibular first molar restored with endocrowns made of ceramic and indirect composites using three-dimensional (3D)-finite element analysis (FEA). Materials and Methods: Two 3D finite element models of mandibular first molar were designed. One model of intact tooth without any restoration was uses as a control. Another mandibular molar model with endocrown as postendodontic restoration was generated where the tooth was simulated with extensive coronal loss and divided into five groups with different materials such as lithium disilicate, zirconia, feldspathic, resin nanoceramic, and polymer infiltrated ceramic network (PICN). An axial loading force of 300 N at five diverse contacts areas was applied on the occlusal surface. Stress distribution at various regions of tooth, concentrating mainly on root dentin and alveolar bone, was measured using the Von Mises stress criteria by FEA software. Results: The lowest stress concentration in root dentin was seen in the cervical root region of resin nanoceramic endocrown group followed by PICN endocrown, feldspathic ceramic endocrown, intact tooth, zirconia endocrown, and lithium disilicate endocrown. In alveolar bone, the result showed that the lowest stress value was seen in resin nanoceramic endocrown, followed by PICN endocrown, zirconia endocrown, feldspathic endocrown, intact tooth, and lithium disilicate endocrown. Conclusion: Endocrown materials with the modulus of elasticity similar to that of dentin showed better stress distribution than the materials with high modulus of elasticity