3种高嵌体修复材料的抗折性能比较

Fracture resistance and failure pattern of three different onlays restorations for endodontically treated premolars

目的:比较3种高嵌体材料修复前磨牙MOD洞型的抗折性能。方法:选取50个健康离体上颌前磨牙,随机分为1个对照组和Ⅰ、Ⅱ、Ⅲ、Ⅳ4个实验组(n=10)。对照组不作任何处理;4个实验组常规根管预备和充填后进行高嵌体MOD洞型预备,其中Ⅰ、Ⅱ、Ⅲ组颊舌尖预备2 mm,Ⅳ组预备1 mm。然后Ⅰ组采用间接复合树脂模块修复,Ⅱ组采用二硅酸锂加强型玻璃陶瓷修复,Ⅲ、Ⅳ组采用氧化锆高嵌体修复。最后用万能材料试验机在负荷1 800 N时检测各组样本的抗折性能,体视显微镜下观察样本折裂的类型。结果:对照组及Ⅰ、Ⅱ、Ⅲ、Ⅳ组抗折力(N)分别为1 135.92±228.61、687.58±107.66、705.41±203.78、1 572.84±243.53和1 012.65±193.80,Ⅲ组与其他各组比,P<0.05;Ⅳ组与对照组相比、Ⅰ组与Ⅱ组相比,P>0.05。Ⅰ、Ⅱ组样本折裂主要为E型,其次为B型;Ⅲ、Ⅳ组样本折裂主要为B型和D型。结论:对于根管治疗后的前磨牙,用氧化锆高嵌体修复较间接复合树脂、二硅酸锂加强型玻璃陶瓷高嵌体修复具有更高的抗折性。

AIM： To compare the fracture resistance and modes of failures of three different aesthetic MOD onlays on endodontically treated premolars. METHODS： 50 sound maxillary premolars were selected, 10 untreated teeth were used as the controls.The other 40 premolars were subjected to standardized MOD onlay preparation and root canal treatment and divided into 4 groups（ n =10）. Onlays of indirect composite and lithium disilicate ceramic were respectively prepared for the restoration of the MOD cavity of group Ⅰand Ⅱ, onlays of Full Zirconiafor for group Ⅲ and Ⅳ. In groupⅠ, Ⅱand Ⅲ buccal and palatal cusps were reduced by 2 mm, and in group Ⅳ by 1 mm. All onlays were cemented using Multilink Automix. All the samples of the 5 groups were subjected to fracture resistance test on universal testing machine. The fractured surfaces were observed under stereo - microscope. RESULTS： The fracture resistance（N） of group control, Ⅰ, Ⅱ, Ⅲ and Ⅳ was 1 135.92±228.61, 687.58±107.66, 705.41±203.78 , 1 572.84±243.53 and 1 012.65±193.80 respectively （group Ⅲ vs the other groups, P 〈0.05;groupⅠ, Ⅱ or Ⅳ vs the control, P 〉0.05）. No crack was observed in the restorations of group Ⅲ. The restorations of group Ⅰ and Ⅱshowed mainly type E fracture mode followed by type B; those of group Ⅲ and Ⅳshowed mainly type A fracture mode. CONCLUSION： Full zirconia MOD onlay has higher fracture resistance for endodontically treated premolars than the other MOD systems.