Graduate student, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, PR China.
Associate Professor, Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, PR China.
J Prosthet Dent. 2020 Jul;124(1):88-93. doi: 10.1016/j.prosdent.2019.08.010. Epub 2019 Oct 29.
Although different preparation designs have been proposed for onlays fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM), their effect on marginal adaptation is unclear.
The purpose of this in vitro study was to investigate the effect of tooth preparation designs on the marginal and internal adaptation of ceramic-reinforced composite resin CAD-CAM onlays.
A traditional preparation with a heavy chamfer on the functional cusp and a contrabevel on the nonfunctional cusp and a shoulder preparation with equal reduction on all cusps were used for mesial-occlusal-distal (MOD) onlay preparations. Ceramic-reinforced composite resin onlays were designed and milled based on the scanned prepared teeth. A digital silicone replica technique was used to determine marginal discrepancies between preparations and onlay restorations. A total of 100 numeric distances (representations of the fit in each region) were measured in 3 distinct regions: the buccal margin, lingual margin, and internal area. Independent Student t tests were used to determine significant differences (α=.05).
Traditional preparation designs resulted in significantly smaller overall discrepancies (50.9 ±0.5 μm and 139.1 ±5.4 μm, P<.001) and smaller marginal discrepancies in the buccal (49.7 ±1.4 μm and 135.8 ±2.2 μm, P<.001) and lingual areas (47.1 ±1.0 μm and 133.4 ±1.1 μm, P<.001).
The marginal adaptation of ceramic-reinforced composite resin CAD-CAM onlays was affected by the preparation design. The traditional preparation design offered better marginal adaptation; therefore, it is recommended in clinical practice.
虽然已经提出了用于计算机辅助设计和计算机辅助制造（CAD-CAM）制作嵌体的不同预备设计，但它们对边缘适应性的影响尚不清楚。
本体外研究的目的是调查预备设计对陶瓷增强复合树脂 CAD-CAM 嵌体的边缘和内部适应性的影响。
使用传统的预备设计，在功能尖上有一个重的斜面，在非功能尖上有一个对斜面，以及在所有尖上有等深的肩台预备。近中-颊舌-远中（MOD）嵌体预备。基于扫描预备的牙齿设计和铣削陶瓷增强复合树脂嵌体。使用数字硅橡胶复制技术来确定预备和嵌体修复体之间的边缘差异。在 3 个不同区域测量了总共 100 个数字距离（每个区域拟合的表示）：颊侧边缘、舌侧边缘和内部区域。使用独立学生 t 检验确定显著差异（α=.05）。
传统预备设计导致整体差异显著减小（50.9 ±0.5μm 和 139.1 ±5.4μm，P<.001），颊侧（49.7 ±1.4μm 和 135.8 ±2.2μm，P<.001）和舌侧区域（47.1 ±1.0μm 和 133.4 ±1.1μm，P<.001）的边缘差异更小。
陶瓷增强复合树脂 CAD-CAM 嵌体的边缘适应性受到预备设计的影响。传统预备设计提供了更好的边缘适应性，因此在临床实践中推荐使用。
