牙本质暴露量对瓷贴面剪切粘接强度的影响

目的在两种新型贴面粘接系统下,探讨不同牙本质暴露量的牙齿表面对瓷贴面剪切粘接强度的影响,以探索最佳的贴面适应证来提高贴面修复成功率。方法设计并制作牙本质暴露量为0%、25%、50%、75%、100%的粘接界面,分为A、B、C、D、E组,使用Variolink~?N和Panavia F两套粘接系统粘接60个4 mm×4 mm×2 mm(长×宽×高)的瓷试件,用Variolink~?N粘接系统粘接VN-A、VN-B、VN-C、VN-D、VN-E组,用Panavia F粘接系统粘接PF-A、PF-B、PF-C、PF-D、PF-E组,每组6个试件。粘接好的标本储存于(37±1)℃的蒸馏水浴中24 h后,万能试验机测试其断裂载荷,扫描电子显微镜观察断裂类型。结果 VN-A组(25.14±3.40)MPa、VN-B组(22.54±4.48)MPa、VN-C组(19.59±2.21)MPa、PF-A组(20.61±2.42)MPa、PF-B组(18.08±4.11)MPa、PF-C组(17.06±2.29)MPa剪切粘接强度都达到17 Mpb以上,VN-A组具有最高的剪切粘接强度值。剪切粘接强度VN-A和VN-B、VN-C组间比较差异无统计学意义(P>0.05),VN-A和VN-D、VN-E组间差异具有统计学意义(P<0.05)。剪切粘接强度PF-A和PF-B组间差异无统计学意义(P>0.05);PF-A组与PF-C、PF-D、PF-E组比较差异有统计学意义(P<0.05)。VN-A组与PF-A组间差异有统计学意义(P<0.05)。断裂模式VN-A、PF-A、VN-B、PF-B、VN-C组以树脂水门汀内聚破坏和混合破坏为主,VN-D、VN-E、PF-C、PF-D、PF-E组以界面破坏和混合破坏为主。结论牙本质暴露量大于50%时显著影响贴面的剪切粘接强度值,为获得较好的临床效果,瓷贴面修复建议牙本质暴露量小于25%。

Effect of dentin exposure on the shear bond strength of cast porcelain veneers

Objective To explore the best indication for veneers and to improve the repair success rate by investigating the effects of different types of dentin exposure on the shear bond strength of cast porcelain veneers with two new veneer bonding systems.Methods Bonding interfaces with 0%,25%,50%,75% and 100% dentin exposure were designed and fabricated.The bonding interfaces were divided into groups A,B,C,D and E.Sixty 4-mm×4-mm×2-mm(length × width × thickness)ceramic specimens were bonded by using two bonding systems,The VN-A,VN-B,VN-C,VN-D and VN-E groups were bonded with Variolink bonding system,and the PF-A,PF-B,PF-C,PF-D and PF-E were bonded with Panavia F bonding system(six specimens per group).The bonded specimens were stored in a distilled water bath at(37+1)℃ for 24 hours.The fracture load was tested by a universal testing machine,and the fracture type was observed by scanning electron microscopy.Results The VN-A(25.14±3.40 MPa),VN-B(22.54±4.48 MPa),VN-C(19.59±2.21 MPa),PF-A(20.61±2.42 MPa),PF-B(18.08±4.11 MPa),PF-C(17.06±2.29 MPa)groups’shear bond strengths were above 17 MPa.The VN-A group had the highest shear bond strength value.There was no statistically significant difference in bond strength between the VN-A group and the VN-B and VN-C groups(P >0.05)or the PF-A and PF-B groups(P >0.05);however,the differences between VN-A and the VN-D and VN-E groups(P<0.05)and between PF-A and the PF-C and PF-D and PF-E groups(P<0.05)were statistically significant.The differences between the VN-A group and PF-A group(P<0.05)were statistically significant.The fracture modes of the VN-A,PF-A,VN-B,PF-B,and VN-C groups mainly included resin cement cohesive failure and mixed failure;the VN-D,VN-E,PF-C,PF-D and PF-E groups were dominated by interface failure and mixed failure.Conclusion When the dentin exposure is greater than 50%,the shear bond strength value of the veneer was significantly affected.To obtain a better clinical effect,the dentin exposure rate should be less than 25%.