Department of Mechanical Engineering, University of Alberta, Edmonton, Canada.
J Biomech. 2013 Jun 21;46(10):1618-25. doi: 10.1016/j.jbiomech.2013.04.011. Epub 2013 May 17.
Maxillary expansion treatment is a commonly used procedure by orthodontists to widen a patient's upper jaw. As this is typically performed in adolescent patients, the midpalatal suture, connective tissue adjoining the two maxilla halves, remains unfused. Studies that have investigated patient response to expansion treatment, generally through finite element analysis, have considered this suture to behave in a linear elastic manner or it was left vacant. The purpose of the study presented here was to develop a model that could represent the midpalatal suture's viscoelastic behavior. Quasilinear viscoelastic, modified superposition, Schapery's, and Burgers modeling approaches were all considered. Raw data from a previously published study using New Zealand White Rabbits was utilized for model parameter estimation and validation. In this study, Sentalloy(®) coil springs at load levels of 0.49N (50g), 0.98N (100g), and 1.96N (200g) were used to widen the midsagittal suture of live rabbits over a period of 6 weeks. Evaluation was based on a models ability to represent experimental data well over all three load sets. Ideally, a single set of model constants could be used to represent data over all loads tested. Upon completion of the analysis it was found that the modified superposition method was able to replicate experimental data within one standard deviation of the means using a single set of constants for all loads. Future work should focus on model improvement as well as prediction of treatment outcomes.
上颌扩张治疗是正畸医生常用的一种方法，用于拓宽患者的上颌。由于这通常在青少年患者中进行，因此中隔骨缝（连接上颌两部分的结缔组织）仍然没有融合。通过有限元分析研究患者对上颌扩张治疗的反应的研究通常认为，该骨缝的行为呈线性弹性，或者被忽略。本研究旨在开发一种能够代表中隔骨缝粘弹性行为的模型。准线性粘弹性、改进的叠加法、Schapery 法和 Burgers 模型法都被考虑。使用从以前使用新西兰白兔的研究中获得的原始数据进行模型参数估计和验证。在这项研究中，使用 Sentalloy（®）螺旋弹簧在 0.49N（50g）、0.98N（100g）和 1.96N（200g）的负载水平下，将活兔的中矢状缝扩大 6 周。评估基于模型在所有三个负载组中很好地代表实验数据的能力。理想情况下，可以使用一组模型常数来表示所有测试负载的数据。完成分析后发现，改进的叠加法能够使用一组常数复制所有负载的实验数据，平均值的一个标准差内。未来的工作应集中于模型改进以及治疗结果的预测。
