Effect of machining method and margin design on the accuracy and margin quality of monolithic zirconia crowns

• Published in: The Journal of prosthetic dentistry 2024-11
• Main Authors: Zhou, Yi, Chen, Wenjia, Zhu, Han, Liu, Xiaochen, Yang, Haiping, He, Fuming
• Format: Article
• Language: English
• ISSN: 0022-3913; 1097-6841; 1097-6841
• DOI: 10.1016/j.prosdent.2024.10.012

The machining accuracy and marginal integrity of monolithic zirconia crowns with minimal invasive preparations may impact the long-term survival rate of tooth and periodontal health, but studies on the effect of machining method are lacking. The purpose of this in vitro study was to digitally evaluate the machining accuracy and margin quality of monolithic zirconia crowns fabricated using gel deposition and conventional soft milling processes by comparing 2 different margin types. A total of 40 monolithic zirconia crowns were produced using gel deposition (Self-glazed Zirconia Group, SGG, n=20) and soft milling (Milled Zirconia Group, MG, n=20). Each group was further divided into 2 subgroups with different margin designs (chamfer and feather-edge). The trueness and fit of crowns were compared using root mean square (RMS) values. Furthermore, the margin quality was examined before and after final sintering with a scanning electron microscope (SEM). The Scheirer-Ray-Hare and 2-way ANOVA test analysis nonparametric and parametric data, respectively (α=.05). The trueness analysis revealed that SGG had significantly lower RMS values for both the cameo and intaglio areas compared with MG (P