Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Alameda Octávio Pinheiro Brisolla 9-75, Bauru, SP 17012-901, Brazil; Post-Graduation Program in Clinical Dentistry, Dental School, Positivo University, 5300 Pedro Viriato Parigot de Souza Rd., Curitiba, PR 81280-330, Brazil.
Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Alameda Octávio Pinheiro Brisolla 7-35, Bauru, SP 17012-901, Brazil.
Dent Mater. 2017 Nov;33(11):e405-e413. doi: 10.1016/j.dental.2017.08.191. Epub 2017 Sep 19.
To evaluate the dimensional changes from the sintering process of Y-TZP and relate them to the fit of zirconia copings.
The sintering shrinkage rate (SSR) was obtained from the measurement of geometric specimens (4×4×2mm). Thirty-six zirconia copings made using CAD/CAM were equally divided into three groups (n=12): ZMAX - IPS e.max ZirCAD (Ivoclar Vivadent, Liechtenstein); ZYZ - InCeram YZ (Vita Zahnfabrik, Germany); and ZK - Zirklein (Zirklein, Brazil). The copings were scanned in micro-CT before and after sintering so that SSR was obtained. The SSR of geometrical specimens and copings was compared to each other and those the manufacturers reported (ANOVA-2 and Tukey, p≤.05). The copings were settled on an abutment and taken to the micro-CT to evaluate their marginal and internal fit. The data enabled the statistical comparison (ANOVA-2 and Tukey, p≤.05) between groups and measurement sites and between the fit obtained with that stipulated by the CAD/CAM software (80μm) (Dunnett test, p≤.05).
All groups showed statistical differences between the SSR the manufacturer reported and those obtained experimentally and between the SSR of the geometric specimens and copings. In general, the SSR of the copings showed no uniformity. There was no statistical difference among the groups for marginal fit, with differences only for internal fit and between the different regions measured. The fit obtained experimentally differed from the internal space determined in the CAD/CAM software.
The lack of uniformity of sintering shrinkage might lead to a non-uniform internal fit of Y-TZP copings.
评估 Y-TZP 烧结过程中的尺寸变化，并将其与氧化锆全冠的适合性相关联。
通过测量几何试件（4×4×2mm）获得烧结收缩率（SSR）。使用 CAD/CAM 制作的 36 个氧化锆全冠被平均分为三组（n=12）：ZMAX-IPS e.max ZirCAD（义获嘉伟瓦登特，列支敦士登）；ZYZ-InCeram YZ（维他，德国）；和 ZK-Zirklein（Zirklein，巴西）。在烧结前后对全冠进行微 CT 扫描，以获得 SSR。将几何试件和全冠的 SSR 进行比较，并与制造商报告的 SSR 进行比较（ANOVA-2 和 Tukey，p≤.05）。将全冠安置在基台上，并用微 CT 评估其边缘和内部适合性。数据分析允许进行组间、测量部位间以及 CAD/CAM 软件规定的适合性（80μm）之间的统计比较（ANOVA-2 和 Tukey，p≤.05）（Dunnett 检验，p≤.05）。
所有组在制造商报告的 SSR 与实验获得的 SSR 之间以及几何试件和全冠的 SSR 之间均显示出统计学差异。总的来说，全冠的 SSR 没有一致性。各组之间的边缘适合性没有统计学差异，只有内部适合性和测量部位之间存在差异。实验获得的适合性与 CAD/CAM 软件中确定的内部空间不同。
烧结收缩率的不一致性可能导致 Y-TZP 全冠的内部适合性不一致。
