Studart A R, Filser F, Kocher P, Gauckler L J
Department of Materials, ETH-Zurich, Zurich, Switzerland.
Biomaterials. 2007 Jun;28(17):2695-705. doi: 10.1016/j.biomaterials.2006.12.033. Epub 2007 Jan 26.
All-ceramic dental restorations exhibit enhanced esthetics and biocompatibility as compared to traditional metal-based prosthesis. However, long-term fatigue and subcritical crack growth in the presence of water and cyclic loading can decrease the strength of ceramic components over time. We investigated the cyclic fatigue in water of three dental materials currently used as frameworks in all-ceramic restorations: a 3 mol%-yttria partially stabilized zirconia (3Y-TZP, Cercon, Degudent GmbH), a Al(2)O(3)-ZrO(2)-Glass composite (Inceram-Zirconia, Vita Zahnfabrik GmbH) and a Li(2)O.2SiO(2) glass ceramic (Empress 2, Ivoclar Vivadent AG). Fatigue and fast fracture tests were performed to determine the Weibull distribution of lifetime and initial mechanical strength for each framework component. In spite of its noticeable susceptibility to fatigue in water, the 3Y-TZP material was found to be particularly suitable for the preparation of posterior all-ceramic bridges due to its high initial mechanical strength. Guidelines are provided for the selection of materials and the design of all-ceramic posterior bridges exhibiting lifetime longer than 20 years under severe wet and cyclic loading conditions.
与传统的金属基修复体相比，全瓷牙科修复体具有更好的美学效果和生物相容性。然而，在水和循环载荷存在的情况下，长期疲劳和亚临界裂纹扩展会随着时间的推移降低陶瓷部件的强度。我们研究了目前在全瓷修复体中用作框架的三种牙科材料在水中的循环疲劳情况：一种3摩尔%氧化钇部分稳定氧化锆（3Y-TZP，Cercon，Degudent GmbH公司）、一种Al(2)O(3)-ZrO(2)-玻璃复合材料（Inceram-Zirconia，Vita Zahnfabrik GmbH公司）和一种Li(2)O.2SiO(2)玻璃陶瓷（Empress 2，Ivoclar Vivadent AG公司）。进行了疲劳和快速断裂试验，以确定每个框架部件的寿命威布尔分布和初始机械强度。尽管3Y-TZP材料在水中对疲劳明显敏感，但由于其较高的初始机械强度，它被发现特别适合制备后牙全瓷桥。文中提供了在严重潮湿和循环载荷条件下，选择材料和设计使用寿命超过20年的后牙全瓷桥的指导原则。
