粘接层厚度对全瓷冠修复效果影响的数值分析

Numerical Analysis of the Influence of Cement Thickness on Stress Distribution in All-ceramic Crowns

目的分析不同粘接层厚度对全瓷冠修复系统在荷载作用下的应力分布情况的影响,为牙齿的全瓷冠修复提供理论依据。方法采用CT断层扫描技术和CAD建模软件相结合的方法,建立下颌第一磨牙模型,采用有限元方法进行应力数值模拟。结果在垂直荷载作用下,近中、远中位置的粘接层中有应力集中产生;粘接层上下表面应力分布形式相似,应力值相差不大;沿特定路径,粘接层厚度0.15 mm模型的颈部应力较0.05 mm模型应力降低近30%。结论粘接层厚度对全瓷修复系统内的应力分布有重要作用,在所研究的3个模型中,粘接层厚度0.15 mm的模型显示出更好的抗破坏能力。

Objective To provide theoretical basis for clinical treatment of all-ceramic crown prosthodontics,the influence of cement thickness on the stress distribution in all-ceramic crowns under load was studied numerically.Methods The finite element analysis（FEA） model of a standard mandibular first molar was established using spiral CT and CAD software,and then it was applied to analyze the stress distribution of all-ceramic crowns under vertical loading using FEA software.Results Stress concentration was found in mesial and distal cement;the stress distribution at the cement upper and lower interface was found to be similar,and the stress magnitude discrepancy between the two interfaces was small;the stress of the model with 0.15 mm cement in the cervix was lower about 30% than the one of the 0.05 mm model.Conclusions The cement thickness plays an important role in the stress distribution of all-ceramic restoration system.The model with 0.15 mm cement shows a better resistance to destruction among the three models investigated.