Katona T R, Chen J
Biomechanics and Biomaterials Research Center, School of Dentistry, Indiana University-Purdue University at Indianapolis.
Am J Orthod Dentofacial Orthop. 1994 Aug;106(2):167-74. doi: 10.1016/S0889-5406(94)70035-4.
The stress levels within the cement layer (hence, the apparent strength) of a direct bonded orthodontic bracket depends, to a large extent, on the alignment of the tensile loads that are applied to the specimen. The purpose of this analysis was to determine how the construction of a ligature wire harness affects the alignment of the applied loads. Tensile tests conducted on a modified bracket/cement system showed large variations in the force-elongation curve profiles. An engineering model was developed to explain these deviations. The results indicate that it is virtually impossible to evenly apply tensile loads to the bracket. It was also proposed that long harnesses constructed with thin ligature wire, prestressing the harness, and lubrication may reduce some of the effects of unavoidable load-bracket misalignment.
直接粘结正畸托槽的粘结层内的应力水平（即表观强度）在很大程度上取决于施加在样本上的拉伸载荷的排列方式。本分析的目的是确定结扎丝束的结构如何影响所施加载荷的排列。在改良的托槽/粘结剂系统上进行的拉伸试验表明，力-伸长曲线轮廓存在很大差异。开发了一个工程模型来解释这些偏差。结果表明，几乎不可能将拉伸载荷均匀地施加到托槽上。还提出，用细结扎丝构建的长丝束、对丝束进行预应力处理以及润滑可能会减少不可避免的载荷-托槽错位的一些影响。
