Abstract: Objective: To compare the stress and its distribution of the residual tooth tissue and the restoration of the mandibular first molar with proximal defect with different heights so as to provide reference for the clinical repair plan. Methods: The mandibular first molar model with proximal defects at different heights was established by finite element method and repaired with endocrown. Then, the vertical and oblique loads were applied, and the size and distribution of EQV stress of residual tooth tissue and restoration were recorded. Results: The EQV stress distribution of the residual tooth tissue and the endocrown was similar in different groups. The maximum EQV stress of the residual tooth tissue and the endocrown increased with the decrease of the residual height. Conclusion: The decrease of the proximal height increases the stress of the endocrown and the residual tooth tissue, and increases the possibility of fracture of the tooth and endocrown.

Key words: Three-dimensional finite element analysis, Equivalent stress, Endocrown, Proximal caries