Eisenburger Michael, Mache Tobias, Borchers Lothar, Stiesch Meike
Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Hannover, Germany.
Eur J Oral Sci. 2011 Jun;119(3):253-7. doi: 10.1111/j.1600-0722.2011.00829.x.
In the current in vitro study, the fracture stability of anterior crowns with zirconia cores of different designs was investigated after applying different veneering techniques. Four groups of zirconia cores (n = 10 in each group) were produced using a computer-aided design/computer-aided manufacturing (CAD/CAM) process. Cores with a standard cervical design were veneered using the layering technique (CCL) or the press-over technique (CCP). Further cores were designed with a porcelain shoulder, where the cervical margin of the zirconia core was reduced by 1 mm. These cores were also veneered using the layering technique (PSL) or the press-over technique (PSP). All crowns were cemented onto metal teeth and loaded until fracture in a universal testing machine. Chipping or fracture of the core was found to occur for CCL at 919±265 N (mean ±SD), for CCP at 798±226 N, for PSL at 739±184 N, and for PSP at 734±209 N. anova did not show significant differences between the four groups. For CCL and CCP, fracture lines ran in a mesio-distal orientation. For PSL and PSP, fracture lines ran into the porcelain shoulder. In summary, the use of a porcelain shoulder can be recommended with zirconia crowns in combination with either the layering or the press-over veneering technique.
在当前的体外研究中，在应用不同的饰面技术后，对具有不同设计的氧化锆核的前牙冠的骨折稳定性进行了研究。使用计算机辅助设计/计算机辅助制造（CAD/CAM）工艺制作了四组氧化锆核（每组n = 10）。采用分层技术（CCL）或压覆技术（CCP）对具有标准颈部设计的核进行饰面。进一步设计了带有瓷肩的核，其中氧化锆核的颈部边缘减少了1毫米。这些核也采用分层技术（PSL）或压覆技术（PSP）进行饰面。将所有牙冠粘固在金属牙上，并在万能试验机中加载直至骨折。发现CCL在919±265 N（平均值±标准差）时发生核的碎裂或骨折，CCP在798±226 N时发生，PSL在739±184 N时发生，PSP在734±209 N时发生。方差分析未显示四组之间存在显著差异。对于CCL和CCP，骨折线呈近远中方向。对于PSL和PSP，骨折线延伸至瓷肩。总之，对于氧化锆牙冠，结合分层或压覆饰面技术时，推荐使用瓷肩。
