CAD/CAM三种修复方式对邻牙合缺损上颌前磨牙抗折性的影响
Fracture resistance of maxillary premolars with mesial occlusal cavity restored with 3 kinds of CAD/CAM ceramic restorations

目的:采用CAD/CAM三种方式修复邻牙合缺损的上颌前磨牙,分析其对抗折性的影响。方法:将32颗上颌前磨牙随机均分为4组。A组不做处理,B、C、D组样本牙经根管治疗后制备邻牙合洞型,然后按嵌体(B组)、高嵌体(C组)、全冠(D组)修复行牙体预备,采用CAD/CAM玻璃陶瓷分组修复。在力学万能实验机上静态加载,记录试件折裂时的载荷值及折裂模式。结果:4组中B组折裂载荷值最低(425.13±56.28)N(P<0.05); C、D组与A组间差异无统计学意义(P>0.05)。折裂模式B、C组以可修复性为主,D组以不可修复性为主。结论:CAD/CAM玻璃陶瓷高嵌体或全冠修复均可恢复邻牙合缺损的上颌前磨牙的抗折强度,其中高嵌体折裂模式为可修复性折裂。
Aim: To assess the fracture resistance of maxillary premolars with mesial occlusal cavity after CAD/CAM ceramic restorations.Methods: Thirty-two intact human maxillary first premolars were randomly assigned into four groups(n=8). The teeth in control group(group A)were not treated. The teeth in the other 3 groups were endodontically treated and all received cavity preparation. Postendodontic restorations for group B,C, and D were inlay, onlay, and full-crown with CAD/CAM milling lithium disilicate reinforced ceramics. Then all the specimens were subjected to fracture failure tests by a universal testing machine. The fracture loads and form were recorded.Results: The teeth in group B presented the lowest fracture resistance values[(425.13±56.28)N](P<0.05). There was no significant difference between group C,D and group A(P>0.05). The teeth in group B and C were mainly in the form of repairable fracture, and those in group D were mainly in the pattern of unrepairable fracture.Conclusion: Postendodontic maxillary premolars with mesial occlusal cavity can recover the strength of the lost dental tissue, when restored with onlay or full-crown by CAD/CAM milling lithium disilicate reinforced ceramics, and teeth with onlay are mainly in the pattern of repairable fracture