关键词: 全瓷冠, 有限元分析, 应力, 饰瓷, 核心瓷

Abstract:

Objective    To investigate the relationship between various veneer layer occlusal thickness and the core layer occlusal thickness and stress distribution of two-tier structure all-ceramic crown，and provide the basis for the design of clinical repair. Methods    The images of spiral CT were used to construct the finite element analysis model，the model is separated into six parts：crown（including the core layer and the veneer layer），agglomerant，prepared tooth ，the root of the tooth，periodontal ligament，and alveolar bone，and load way was designed：600 N load was vertically concentrated，and ANSYS software was used to analyze the stress values（S1）of two-tier structure all-ceramic crown between various veneer layer occlusal thickness（V）and the thickness of the core layer occlusal（C）. Results    With the increase of the thickness of veneer layer，the stress decreased first and then rose with decorated porcelain thickness of 0.7 mm，S1 was 73.20 MPa. When it rose to 0.9  mm，S1 decreased to 54.56 MPa. When thickness rose to 1.7 mm，S1 rose up to 60.16 MPa. The stress of the core porcelain decreased with the increase in the thickness of the core porcelain，and when the core porcelain thickness was 0.3 mm，S1 was 116.40 MPa. When thickness rose to 1.3 mm，the S1 was decreased to 4.17 MPa，the stress peak decreased 96.75%. Conclusion    From the stress analysis for all-ceramic crowns，you can know the V and C range of the double-layer all-ceramic crowns：0.9 mm≤ V ≤1.5 mm，C≥ 0.5 mm. This requires that at least a space of 1.4 mm must be left during the clincal preparation of all-ceramic crowns.

Key words: all-ceramic crown, finite element analysis, stress, veneer layer, core layer