Sturdevant J R, Bayne S C, Heymann H O
University of North Carolina School of Dentistry, Chapel Hill, USA.
J Esthet Dent. 1999;11(4):206-14. doi: 10.1111/j.1708-8240.1999.tb00400.x.
The goal of this study was to determine if the fit of second-generation computer-assisted design/computer-assisted manufacturing (CAD/CAM) (CEREC 2, Sirona Dental Systems, Bensheim, Germany) inlays within Class II cavity preparations were within the range of 50 to 100 microns and were equal or better to CEREC 1 inlays.
Extracted human molars free of surface defects and caries were prepared with standard mesio-occlusodistal cavity preparations. Ceramic inlays were fabricated with CEREC 2 CAD/CAM equipment and seated into cavity preparations. Digital images were captured at 100 times magnification. Marginal gaps were measured with an image analysis program. For each restoration, gaps were measured at 12 locations along interproximal margins and 10 locations along occlusal margins.
No difficulty occurred in seating any of the milled inlays. Average marginal gaps for occlusal (59 +/- 35 microns) and interproximal (97 +/- 66 microns) margins were statistically different (t-test, p < or = .01). Average marginal gap for all sites combined was 80 +/- 57 microns. Marginal gap widths were smaller than those obtained from a similar study done earlier with the CEREC 1 unit for occlusal (89 +/- 65 microns) and interproximal (105 +/- 81 microns) margins. Ease of seating with CEREC 2 inlays was much better than with CEREC 1.
Improvements in software and hardware allow the CEREC 2 to adapt well to standard inlay cavity preparations. The ability of the device to create inlays that seat without interference is remarkable. The improved fit and ability to create the occlusal surface in a variety of ways make CEREC 2 an attractive restorative option for all-ceramic restorations.
本研究的目的是确定第二代计算机辅助设计/计算机辅助制造（CAD/CAM）（德国本斯海姆西诺德牙科系统公司的CEREC 2）嵌体在II类洞型预备中的适合度是否在50至100微米范围内，并且是否等同于或优于CEREC 1嵌体。
选取无表面缺陷和龋齿的拔除人类磨牙，制备标准近中-咬合-远中洞型。使用CEREC 2 CAD/CAM设备制作陶瓷嵌体，并将其就位到洞型预备中。以100倍放大倍数拍摄数字图像。使用图像分析程序测量边缘间隙。对于每个修复体，在邻面边缘的12个位置和咬合边缘的10个位置测量间隙。
所有研磨嵌体就位均无困难。咬合边缘（59±35微米）和邻面边缘（97±66微米）的平均边缘间隙在统计学上有差异（t检验，p≤0.01）。所有部位的平均边缘间隙为80±57微米。边缘间隙宽度小于早期使用CEREC 1设备对咬合边缘（89±65微米）和邻面边缘（105±81微米）进行的类似研究所得结果。CEREC 2嵌体的就位容易程度远优于CEREC 1。
软件和硬件的改进使CEREC 2能很好地适应标准嵌体洞型预备。该设备制作的嵌体能够无干扰地就位，这一能力非常显著。更好的适合度以及以多种方式制作咬合面的能力使CEREC 2成为全瓷修复的一个有吸引力的修复选择。
