不同基底对Sirona CEREC Blocs可切削陶瓷断裂强度的影响

目的：研究不同材料及形状的基底代型对Sirona CEREC Blocs可切削陶瓷断裂强度的影响.方法：选择人第三磨牙12颗,随机分为2组.第1组垂直于牙长轴去除骀面釉质,第2组制成牙本质片.用FiltekZ250光固化复合树脂分别复制第一组和第二组试件各6颗.用Multilink9 Speed树脂粘接剂将瓷片粘接于所有基底代型试件上,粘接1h后储存于37℃蒸馏水中24h,然后测试瓷片断裂强度值,并在光学显微镜下观察粘接破坏情况.结果：树脂牙代型做基底时,瓷片的断裂载荷最高,与离体牙组差异有统计学意义（P＜0.05）,但与树脂片组间差异无统计学意义（P＞0.05）.离体牙组的瓷片断裂载荷高于牙本质片组,差异有统计学意义（P＜0.05）.结论：不同材料及形状的基底代型对全瓷材料的强度均有影响,光固化复合树脂做基底时无论是牙状还是片状,瓷片的断裂载荷都高于对应的离体牙组.

The effect of substrates with different materials and shapes on the fracture load of sirona CEREC blocs

Objective： To investigate the effect of two substrate materials with different shapes on the fracture load of Sirona CEREC Blocs. Methods： Twelve human third molars were selected in the study. The specimens were divided into two groups with 6 in each group： （1） the tooth that the occlusal surface enamel was removed, （2） the dentin piece. The Fil- tek Z250 composite resin was used to duplicate every specimen of the groups of（l） and （2） as substrates. One hour after the ceramic specimens were cemented on the substrates with Multilink~ Speed resin adhesive system, they were stored in dis- tilled water at 37~C for 24 hours prior to fracture testing. Then the fracture load was tested in a universal testing machine. Results： The mean fracatre load was highest when the composite resin with the shape of tooth was used as the substrate, which had significant differences with that of the human teeth group （P〈 0.05）, but not with the composite resin piece group（P〉0.05）. The fracture load of human tooth group was significant higher than that of the dentin piece group （P〈0.05）. Conclusions： The substrate materials and shapes had a significant influence on fractttre strength of the Sirona CEREC Blocs. The fracture loads of light-cured composite resin groups were higher than that of the corresponding human tooth groups no matter the substrate was the tooth shape or piece shape.