不同预备方式的全瓷贴面抗折性研究

Fracture Resistance of Ceramic Veneers with Different Preparation Designs

目的:研究不同牙体预备方式下全瓷贴面的抗折强度。方法:40颗完整的上颌中切牙通过以下五种设计进行贴面预备,每组各8颗:P2e;P4e;P2d;P4d;Pc。瓷贴面经制作、粘结及热循环处理后加载直到破裂。记录各样本抗折强度并进行数据分析。结果:P2e和P2d折裂载荷值与Pc接近;P4d折裂载荷值低于P2e和P2d(P<0.05)。P2e折裂载荷值和P4e、P4d间有显著性差异(P<0.05)。结论:切端去除2mm的贴面抗折强度与完整牙相近,不管唇面预备在本质或釉质内。切端去除4mm并唇面预备在本质内的贴面抗折强度明显低于切端去除2mm。

Objective： To examine the fracture load of ceramic veneers with different preparation designs. Methods： Forty intact human maxillary central incisors were prepared according to five preparation designs, and there were eight teeth in each group： P2e; P4e; P2d; P4d; and Pc. Ceramic veneers were fabricated and cemented, then samples were loaded until fracture following the thermocycling process. Statistical analyses were performed using analysis of variance （ANOVA）. Results： There was no difference in fracture loads between ceramic veneers in P2e group, P2d group and Pc group. Fracture loads yielded by ceramic veneers in P4d group were significantly lower than those in P2e group and P2d group （P〈0.05）. Fracture loads yielded by ceramic veneers in P2e group were significantly higher than those in P4e group and P4d group （P〈0.05）. Conclusion： Veneers with 2-mm incisal reduction exhibited similar fracture resistance to intact tooth for preparation designs supplied on both enamel and dentin. Ceramic veneers with preparation designs entirely on dentin with 4-mm incisal reduction yielded lower fracture loads than those prepared with 2-mm incisal reduction.