PhD student, Graduate Program in Dentistry, School of Health Sciences, Positivo University (UP), Curitiba, Brazil.
Professor, Department of Mechanical Engineering, Positivo University (UP), Curitiba, Brazil.
J Prosthet Dent. 2024 Jun;131(6):1159.e1-1159.e10. doi: 10.1016/j.prosdent.2024.03.005. Epub 2024 Apr 5.
The type of veneer preparation is often chosen according to the patient's tooth structure and occlusion. Taking biomechanics into account in this decision-making process provides the clinician with more technical information on how to improve the clinical longevity of restorations. However, biomechanical analyses of veneer preparation designs are sparse.
The purpose of this 3-dimensional (3D) finite element analysis with microcomputed tomography (µCT) data obtained from realistic models was to assess the influence of different preparations for ceramic and composite resin veneers on restoration and resin layer stress distribution.
Four replicas of a central incisor were printed and prepared for laminate veneers with 4 different incisal edge designs: shoulder (SH), palatal chamfer (PC), palatal chamfer and oblique fracture involving the distal angle (OF-PC), and palatal chamfer involving horizontal incisal fracture (IF-PC). After fabrication and cementation of the veneers, the restored replicas were assessed with µCT, and 3D finite element models were built. A 100-N load was applied on the palatal surface at 60 and 125 degrees relative to the longitudinal axis. Maximum principal stress and stress distribution on the veneers, cement layer, and tooth structure were calculated and analyzed.
The SH preparation exhibited better stress distribution than the PC preparation, and the cement layer and the veneer were subjected to lower stress. The IF-PC preparation had better stress distribution than the OF-PC. The shoulder and IF-PC showed higher stress on laminate veneers, but lower stress on the cement layer. Ceramic veneers exhibited lower stress than composite resin veneers.
The different incisal preparations for laminate veneers influenced stress distribution on restorations and on the resin cement layer. The shoulder type preparation showed better stress distribution and the composite resin veneers showed unfavorable results compared with the ceramic veneers.
贴面准备的类型通常根据患者的牙齿结构和咬合来选择。在这个决策过程中考虑生物力学可以为临床医生提供更多关于如何提高修复体临床寿命的技术信息。然而，贴面准备设计的生物力学分析很少。
本研究通过从现实模型中获得的三维（3D）有限元分析和微计算机断层扫描（µCT）数据，旨在评估不同的陶瓷和复合树脂贴面预备对修复体和树脂层应力分布的影响。
打印了 4 个中切牙的复制品，并为层压贴面准备了 4 种不同的切缘设计：肩台（SH）、腭斜面（PC）、腭斜面和涉及远中角的斜折（OF-PC）以及涉及水平切折的腭斜面（IF-PC）。制作和粘结贴面后，用µCT 评估修复后的复制品，并建立 3D 有限元模型。在相对于长轴 60 和 125 度的腭面施加 100-N 的负载。计算和分析了贴面、粘结层和牙体结构上的最大主应力和应力分布。
SH 预备比 PC 预备显示出更好的应力分布，粘结层和贴面承受的应力较低。IF-PC 预备的应力分布优于 OF-PC。肩台和 IF-PC 在层压贴面中表现出较高的应力，但在粘结层中表现出较低的应力。陶瓷贴面的应力低于复合树脂贴面。
层压贴面的不同切缘预备方式影响修复体和树脂粘结层的应力分布。肩台式预备显示出更好的应力分布，与陶瓷贴面相比，复合树脂贴面的结果不理想。
