关键词: 楔状缺损, 三维有限元法, 修复, 应力

Abstract: Objective    To analyze the stress distribution in deep wedge-shaped defect tooth that is repaired by different methods using three-dimensional finite element method. Methods    A first mandibular premolar extracted for orthodontic treatment from an outpatient visiting Shanghai Stomatological Disease Center was selected as a research sample. Micro-CT scanning and four softwares were used to reconstruct the deep wedge-shaped defect model of the first mandibular premolar. Composite resin and porcelain inlay were used to repair the defect. The defects were prepared by two methods respectively，one with undercut and the other without undercut. After loading 200N vertical force，finite element analysis software was applied to analyze the stress. Results    The stress in the tooth cervix was significantly reduced after filling. The most significant reduction of the equivalent stress was found in the model that was repaired by ceramic inlay. There was no significant difference in the restorations displacement or buccal tip displacement in each model. In the Ⅲ wedge-shaped defect models，the resin model has the lowest equivalent stress and maximum stress of restoration. In the Ⅳ wedge-shaped defect models，the porcelain inlay model has the lowest equivalent stress and maximum stress of restoration. There was no significant difference between two resin models in the restoration equivalent stress.   Conclusion    Filling the deep wedge-shaped defect can relieve the stress concentration in the hard tissue of defected area. When the defect is Ⅲ degree deep，composite resin restoration is recommended. When the defect is Ⅳ degree deep，porcelain inlay restoration is recommended. Adding undercut is recommended when composite resin restoration is selected.

Key words: wedge-shaped defect, three-dimensional finite element method, repair, stress