School of Dentistry and Institute of Oral Medicine, Medical College, National Cheng Kung University, Tainan, Taiwan, Republic of China.
Division of Prosthodontics, Department of Stomatology, National Cheng Kung University Hospital, National Cheng Kung University, Tainan, Taiwan, Republic of China.
BMC Oral Health. 2021 May 16;21(1):264. doi: 10.1186/s12903-021-01630-z.
This study evaluates the mechanical performance of deep margin elevation technique for carious cavities by considering the shape designs and material selections of inlay using a computational approach combined with the design of experiments method. The goal is to understand the effects of the design parameters on the deep margin elevation technique and provide design guidelines from the biomechanics perspective.
Seven geometric design parameters for defining an inlay's shape of a premolar were specified, and the influence of cavity shape and material selection on the overall stress distribution was investigated via automated modelling. Material selection included composite resin, ceramic, and lithium disilicate. Finite element analysis was performed to evaluate the mechanical behavior of the tooth and inlay under a compressive load. Next, the analysis of variance was conducted to identify the parameters with a significant effect on the stress occurred in the materials. Finally, the response surface method was used to analyze the stress responses of the restored tooth with different design parameters.
The restored tooth with a larger isthmus width demonstrated superior mechanical performance in all three types of inlay materials, while the influence of other design parameters varied with the inlay material selection. The height of the deep margin elevation layer insignificantly affected the mechanical performance of the restored tooth.
A proper geometric design of inlay enhances the mechanical performance of the restored tooth and could require less volume of the natural dentin to be excavated. Furthermore, under the loading conditions evaluated in this study, the deep margin elevation layer did not extensively affect the strength of the tooth structure.
本研究通过计算方法结合实验设计方法，评估了嵌体深边缘抬高技术的力学性能，考虑了嵌体的形状设计和材料选择。目的是从生物力学角度了解设计参数对深边缘抬高技术的影响，并提供设计指南。
指定了前磨牙嵌体形状的七个几何设计参数，并通过自动化建模研究了腔形和材料选择对整体应力分布的影响。材料选择包括复合树脂、陶瓷和锂硅二酸盐。通过有限元分析评估了在压缩载荷下牙齿和嵌体的力学行为。然后，进行方差分析以确定对材料中发生的应力有显著影响的参数。最后，使用响应面法分析了不同设计参数下修复牙的应力响应。
在所有三种嵌体材料中，具有较大桥体宽度的修复牙表现出更好的力学性能，而其他设计参数的影响随嵌体材料选择而变化。深边缘抬高层的高度对修复牙的力学性能影响不大。
适当的嵌体几何设计可以提高修复牙的力学性能，并且可以减少对天然牙本质的挖掘量。此外，在本研究评估的载荷条件下，深边缘抬高层对牙体结构的强度没有显著影响。
