三种二硅酸锂玻璃陶瓷冠密合性的比较

Comparison of adaptation of crowns of different lithium disilicate glass-ceramic

目的探讨3种二硅酸锂玻璃陶瓷冠的密合性及不同制备工艺对二硅酸锂玻璃陶瓷冠密合性的影响，以期为临床提供参考。方法30颗下颌第一磨牙标准预备体代型均分为A、B、C3组（每组10颗），分别制作国产二硅酸锂玻璃陶瓷冠、IPSe-maxCAD冠、IPSe-maxPress冠。3组全瓷冠粘接、包埋、切割后，利用激光扫描共聚焦显微镜观察冠边缘、肩台、轴面、骀面、轴面角处各测量点粘接剂厚度，即修复体密合性。结果3组各测量点粘接剂厚度总体差异均有统计学意义（P〈0．05）。A组边缘密合性最好[（46．8±9．1）μm]；B组肩台[（59．3±7．9）μm]、轴面[（50．5±3．6）μm）]和验面[（87．6±11．6）μm]密合性最好；C组轴面角[（84．4±10．1）μm]密合性最好。除轴面角外，A、B组各测量点粘接剂厚度均显著小于C组（P〈0．05）。结论3种二硅酸锂玻璃陶瓷均可满足临床全冠的密合性要求。

Objective To evaluate the adaptation of different lithium disilieate glass-ceramic crown and whether different fabrication processes affect the adaptation of crowns. Methods Thirty epoxy dies crowns were divided into 3 groups. They were cemented to domestic lithium disilicate glass-ceramic crowns in Group A, to IPS e.max CAD crowns in Group B and to IPS e.max Press crowns in Group C respectively. All crowns were cut by cutting machine. A confoeal laser scanning microscope was used to measure the gap between crown tissue surface and die. Results There were significant differences in the three groups of measurement points（P〈0.05）. Within the groups, specimens in group A showed in the lowest marginal fit（[46.8±9.1]μm）. Those in group B showed the lowest shoulder suitability（[59.3±7.9] μm）, axial plane（[50.5±3.6] μm） and ocelusal surface（[87.6±11.6 ]μm]. Those in group C demonstrated the lowest axial plane angle[（84.4±10.1） μm]. In addition to the axial plane angle, the CAD/CAM system exhibited good accuracy of fit. Conclusions The three groups of lithium disilicate glass-ceramic crowns appeared to have clinically acceptable fit.