CAD/CAM全瓷冠边缘适合性的评价

Evaluation on the Marginal Adaptation of CAD/CAM Ceramic Crown

目的:研究采用计算机辅助设计及制作系统(Kavo Everest)制作的氧化锆全瓷冠的边缘适合性。方法:选取1颗无龋的离体前磨牙行牙体预备,双重印模法取模,翻制20个相同尺寸的超硬石膏代型,将代型随机分为2组,分别制作10个金属烤瓷冠和10个Kavo Everest氧化锆全瓷冠。然后采用双色硅橡胶印模法复制间隙模型,应用光学显微镜采集间隙图像及使用AutoCAD2006软件对其厚度进行测量。结果:利用失蜡铸造法制作的金属烤瓷冠的垂直边缘间隙(69.6±29.7)μm,水平边缘间隙(56.1±20.8)μm,绝对边缘间隙(91.1±28.8)μm;利用CAD/CAM制作的氧化锆全瓷冠的垂直边缘间隙(51.4±19.9)μm,水平边缘间隙(41.1±16.8)μm,绝对边缘间隙(66.2±21.9)μm。两种系统制作的冠的水平边缘间隙、垂直边缘间隙、绝对边缘间隙均具有显著性差异(P<0.05)。结论:利用Kavo Everest系统制作的全瓷冠具有良好的边缘适合性。

objective：To evaluate the marginal adaptation of the crowns made by the computer-assisted designing/computer-assisted manufacturing system（Kavo,Biberach,Germany）.Methods：One extracted maxillary premolar without caries was prepared for crown fabrication.A negative impression was made by double impression,and 20dies of the same size was made by super-hard plaster.The dies were divided into 2groups randomly,Ten crowns were made for porcelain fused to metal and ten crowns were made for Kavo Everest.Results：The mean values and standard deviations at the vertical marginal discrepancy was 69.6±29.7μm,horizontal marginal discrepancy was 56.1±20.8μm,absolute marginal discrepancy was 91.1±28.8μm for control.while that of Kavo Everest System was 51.4±19.9μm,41.1±16.8μm,66.2±21.9μm.Compared with the control group,the Kavo Everest group exhibited significantly smaller horizontal marginal discrepancy,vertical marginal discrepancy and absolute marginal discrepancy（P0.000）.Conclusion：Within the limit of this in vitro study,the Kavo Everest System demonstrated a smaller and more homogeneous marginal discrepancies compared with the metal ceramic（control） restoration.