Fischer H, Schäfer M, Marx R
Department of Dental Prosthetics, Section of Dental Materials, University RWTH Aachen, Germany.
J Dent Res. 2003 Dec;82(12):972-5. doi: 10.1177/154405910308201207.
The strength of ceramic restorations depends on the occlusal surface roughness of the veneering porcelain, which is influenced by the final preparation. The hypothesis of the study was that roughnesses below a critical microscopic defect size--based only on fracture mechanics considerations--also affect flexural strength. The bending failure stress was evaluated on standard specimens of 4 veneer ceramics with 4 different surfaces of defined roughnesses, respectively. A linear correlation was found between roughness and failure stress. A "roughness-free" failure stress value was predicted for each tested material. This theoretical value can represent the "true" strength of the respective ceramic material. We conclude from our results that the final preparation of a ceramic restoration is critical to the strength of the material, and that ceramic veneering materials can be compared more objectively with respect to their strength by means of roughness-free strength values.
陶瓷修复体的强度取决于饰面瓷的咬合面粗糙度，而这又受最终预备的影响。本研究的假设是，仅基于断裂力学考虑，低于临界微观缺陷尺寸的粗糙度也会影响弯曲强度。分别在具有4种不同定义粗糙度表面的4种饰面陶瓷的标准试件上评估弯曲破坏应力。发现粗糙度与破坏应力之间存在线性相关性。为每种测试材料预测了一个“无粗糙度”的破坏应力值。该理论值可代表相应陶瓷材料的“真实”强度。我们从结果中得出结论，陶瓷修复体的最终预备对材料强度至关重要，并且通过无粗糙度强度值可以更客观地比较陶瓷饰面材料的强度。
