Department of Computerized Restorative Dentistry, Center of Dental Medicine, University of Zurich, Switzerland.
Department of Cariology, Restorative Sciences and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, MI.
J Prosthodont. 2019 Feb;28(2):e504-e509. doi: 10.1111/jopr.12770. Epub 2018 Mar 6.
A wide variety of CAD/CAM materials are available for single-tooth restorations. CAD/CAM material characteristics are different and may influence CAM fabrication accuracy. There is no study investigating the influence of different CAD/CAM materials on the final fit of the restoration. The aim of this study was to evaluate the fit of endocrowns fabricated from different CAD/CAM materials using a new 3D evaluation method with an intraoral scanning system. The null hypothesis was that there are no significant differences for the fitting accuracy of different CAD/CAM materials.
Preparation for an endocrown was performed on a maxillary right first molar on a typodont, and restorations were fabricated with a chairside CAD/CAM system (CEREC Omnicam, MCXL). Three groups using three different CAD/CAM materials were established (each n = 10): zirconia-reinforced lithium silicate ceramic (Celtra Duo; CD), leucite-reinforced silicate ceramic (Empress CAD; EM), resin nanoceramic (Lava Ultimate; LU). A 3D digital measurement technique (OraCheck, Cyfex AG) using an intraoral scanner (CEREC Omnicam) was used to measure the difference in fit between the three materials for a master endocrown preparation. The preparation scan and the endocrown fit scan were matched with special difference analysis software OraCheck. Three areas were selected for fitting accuracy measurements: margin (MA), axial (AX), occlusal (OC). Statistical analysis was performed using 80% percentile, one-way ANOVA, and post-hoc Scheffé test. Significance level was set to p = 0.05.
Results varied from best 88.9 ± 7.7 μm for marginal fit of resin nanoceramic restorations (LU_MA) to worst 182.3 ± 24.0 μm for occlusal fit of zirconia-reinforced lithium silicate restorations (CD_OC). Statistically significant differences were found both within and among the test groups. Group CD performed statistically significantly different from group LU for marginal fit (MA) and axial fit (AX) (p < 0.05). For occlusal fit (OC), no statistically significant differences were found within all three test groups (p > 0.05). Deviation pattern for differences was visually analyzed with a color-coded scheme for each restoration.
Statistically significant differences were found for different CAD/CAM materials if the CAM procedure was identical. Within the limitations of this study, the choice of CAD/CAM material may influence the fitting accuracy of CAD/CAM-fabricated restorations.
可用于单颗修复的 CAD/CAM 材料种类繁多。CAD/CAM 材料特性不同，可能会影响 CAM 制造精度。目前尚无研究探讨不同 CAD/CAM 材料对修复体最终拟合度的影响。本研究旨在使用新的基于口内扫描系统的 3D 评价方法评估不同 CAD/CAM 材料制作的嵌体的适合性。零假设为不同 CAD/CAM 材料的拟合精度无显著差异。
在牙体模型上颌右侧第一磨牙上进行嵌体预备，并使用椅旁 CAD/CAM 系统（CEREC Omnicam，MCXL）制作修复体。建立了三组使用三种不同 CAD/CAM 材料的实验组（每组 n = 10）：氧化锆增强硅酸锂陶瓷（Celtra Duo；CD）、锂辉石增强硅酸锂陶瓷（Empress CAD；EM）、树脂纳米陶瓷（Lava Ultimate；LU）。使用口内扫描仪（CEREC Omnicam）的 3D 数字测量技术（OraCheck，Cyfex AG）测量三种材料的主嵌体预备体之间的适合性差异。预备体扫描和嵌体适合性扫描通过特殊的差异分析软件 OraCheck 进行匹配。选择三个区域进行拟合精度测量：边缘（MA）、轴面（AX）、颌面（OC）。使用 80%百分位数、单因素方差分析和事后 Scheffé 检验进行统计学分析。显著性水平设为 p = 0.05。
树脂纳米陶瓷修复体的边缘适合度最佳，为 88.9 ± 7.7 μm（LU_MA），氧化锆增强硅酸锂修复体的颌面适合度最差，为 182.3 ± 24.0 μm（CD_OC）。组内和组间均存在统计学差异。组 CD 在边缘适合度（MA）和轴面适合度（AX）方面与组 LU 存在统计学差异（p < 0.05）。而在颌面适合度（OC）方面，三组内无统计学差异（p > 0.05）。用每个修复体的彩色编码方案对差异的偏差模式进行了视觉分析。
在 CAD/CAM 程序相同的情况下，不同 CAD/CAM 材料之间存在统计学差异。在本研究的限制范围内，CAD/CAM 材料的选择可能会影响 CAD/CAM 制作修复体的拟合精度。
