Abstract:

BACKGROUND: The mechanical composition of tooth tissue is complicated, the teeth, periodontal membrane, alveolar bone, mucosa are not linear materials, therefore they are not directly simulated. Three-dimensional finite element can simplify complex biological systems into a model analyzed by computer, and conduct biomechanical research through the model analysis.
OBJECTIVE: Using three-dimensional finite element analysis, the aim of this study is to analyze three kinds of post-core materials that are common used in clinics, to detect Von Mises stress of the residual dentin and posts after repair of maxillary central incisors, and quantify optimal diameter of the posts for different materials.
METHODS: Three-dimensional finite element model was constructed with CT data read by Mimics software. Ansys software was used to simulate cobalt-chromium alloy post, zirconium oxide post and glass fiber post for post and core restoration of the maxillary central incisor. The Von Mises stress peak of the restored residual dentin and the post were detected, the influence of post diameter and elastic modulus on post-core-crown restoration effect was observed.
RESULTS AND CONCLUSION: Repairing maxillary central incisor with different materials at the same diameter, the Von Mises stress peak of the residual dentin decreased, but that of the posts increased along with the increasing elastic modulus of the posts. In post-core-crown restoration with the same material at different diameters, a critical point of post diameter was found. When the diameter of post was less than the critical point, the Von Mises stress peak of residual dentin was decreased with the increment of diameter. Exceeding the critical point, the stress peak was increased with the diameter increment. Repairing maxillary central incisor with high elastic modulus materials can decrease the stress peak of the residual dentin, but the stress distribution of root is changed, leading to obvious stress concentration. Repairing maxillary central incisors with the same material of post and core, the Von Mises stress peak of the residual dentin could firstly decrease and then increase with the post diameter increases; Three-dimensional finite element analysis show that the optimal diameter of cobalt-chromium alloy post, zirconium oxide post and glass fiber post for maxillary central incisors repair is 1.4, 1.4, 1.6 mm respectively.