不同切端设计的上前牙瓷贴面受载能力的定量研究

目的 瓷贴面因美观、微创的特点在临床上广为应用,但其使用寿命和破坏载荷的相关数据目前尚不清楚.该研究通过体外实验测定不同材料、不同设计的上前牙瓷贴面可承受的最大应力载荷,为前牙瓷贴面修复提供基础数据.方法 160颗离体上中切牙,随机分为8组,分别按照对接、切端包绕设计行牙体预备,用铸造玻璃陶瓷和氧化锆陶瓷制作贴面,并粘接;在万能测试机上进行不同受力方向的最大载荷实验,考察修复体对载荷的承受能力.结果 以60°和125°方向加载时,铸造玻璃陶瓷贴面的对接设计对载荷的承受能力均高于切端包绕设计,而切端包绕设计更利于氧化锆瓷贴面对载荷应力的分布.在以60°方向加载时,对于切断包绕设计,氧化锆陶瓷对载荷的承受能力明显优于铸造玻璃陶瓷,但对于对接设计,二者间并无明显差异.以125°方向加载时,在同种设计中,无论是切端包绕设计或对接设计,氧化锆陶瓷可承受的最大应力载荷均高于铸造玻璃陶瓷.结论 切端包绕设计的应力抵抗优于切端对接设计;氧化锆贴面目前存在粘接困难,但其破坏强度明显优于铸造玻璃陶瓷,有较好的潜在应用价值.

Quantitative analysis of the load tolerance of maxillary incisors with ceramic-laminated veneers for various incisal margin preparations

Objective Ceramic-laminated veneer has been extensively used in clinics due to its aesthetics and minimally invasive performance. However, its working life and load tolerance remain unclear. This in vitro study aimed to investigate the stress tolerance of different ceramic-laminated veneer designs and materials for incisor restorations. Methods A total of 160 extracted human maxillary incisors were randomly divided into eight groups. Each group was assigned with tooth preparations of the palatal chamfer design or butt joint design, and the materials used were castable glass ceramic or zirconia ceramic. The veneers were bonded to the teeth and subsequently subjected to a maximum loading test on a universal testing machine in different loading angles to check the load tolerance. Results The load tolerance of the butt joint design with castable glass ceramic-laminated veneers was better than that of the palatal chamfer design at both loading angles of 60° and 125°. However, the palatal chamfer design with zirconia ceramic had better concentrated stress distribution. With the 60° loading angle, the palatal chamfer design with zirconia ceramic tolerated the load better than that with the castable glass ceramic. However, they were not significantly different from the butt joint design. At the loading angle of 125°, the zirconia ceramic-laminated veneers showed significantly better load tolerance for both the palatal chamfer design and the butt joint design. Conclusion The palatal chamfer design showed significantly better load tolerance than the butt joint design. Although bonding difficulties were observed in the zirconia ceramic-laminated veneer, the material still had potential clinical application value due to the favorable stress tolerance.