School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW, 2006, Australia.
Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi, 9808575, Japan.
J Mech Behav Biomed Mater. 2022 Dec;136:105483. doi: 10.1016/j.jmbbm.2022.105483. Epub 2022 Oct 4.
The fibula free flap (FFF) has been extensively used to repair large segmental bone defects in the maxillofacial region. The reconstruction plate plays a key role in maintaining stability and load-sharing while the fibula unites with adjacent bone in the course of healing and remodeling. However, not all fibula flaps would fully unite, and fatigue of prosthetic devices has been recognized as one major concern for long-term load-bearing applications. This study aims to develop a numerical approach for predicting the fatigue life of the reconstruction plate by taking into account the effect of ongoing bone remodeling.
The patient-specific mandible reconstruction with a prosthetic system is studied in this work. The 3D finite element model with heterogeneous material properties obtained from clinical computerized tomography (CT) data is developed for bone, and eXtended Finite Element Method (XFEM) is adopted for the fatigue analysis of the plate. During the remodeling process, the changing apparent density and Young's modulus of bone are simulated in a step-wise fashion on the basis of Wolff's law, which is correlated with the specific clinical follow-up. The maximum biting forces were considered as the driving force on the bone remodeling, which are measured clinically at different time points (4, 16 and 28 months) after reconstruction surgery.
Under various occlusal loadings, the interaction between fatigue crack growth and bone remodeling is investigated to gain new insights for the future design of prosthetic devices. The simulation results reveal that appropriate remodeling of grafted bone could extend the fatigue life of fixation plates in a positive way. On the other hand, the rising occlusal load associated with healing and remodeling could lead to fatigue fracture of fixation plate and potentially cause severe bone resorption.
This study proposes an effective approach for more realistically predicting fatigue life of prosthetic devices subject to a tissue remodeling condition in-silico. It is anticipated to provide a guideline for deriving an optimal design of patient-specific prosthetic devices to better ensure longevity.
游离腓骨皮瓣（FFF）已广泛用于修复颌面区域的大段骨缺损。在腓骨与相邻骨愈合和重塑过程中，重建板在维持稳定性和分担负荷方面起着关键作用。然而，并非所有腓骨皮瓣都能完全愈合，而假体装置的疲劳已被认为是长期承载应用的主要关注点之一。本研究旨在开发一种数值方法，通过考虑正在进行的骨重塑的影响来预测重建板的疲劳寿命。
本工作研究了带有假体系统的患者特异性下颌骨重建。从临床计算机断层扫描（CT）数据获得的具有异质材料特性的三维有限元模型是为骨开发的，并且采用扩展有限元法（XFEM）进行板的疲劳分析。在重塑过程中，根据 Wolff 定律以逐步方式模拟骨的表观密度和杨氏模量的变化，该定律与特定的临床随访相关。最大咬合力被认为是骨重塑的驱动力，这些力是在重建手术后不同时间点（4、16 和 28 个月）临床测量的。
在各种咬合载荷下，研究了疲劳裂纹扩展与骨重塑之间的相互作用，以获得假体装置未来设计的新见解。模拟结果表明，适当的移植骨重塑可以以积极的方式延长固定板的疲劳寿命。另一方面，与愈合和重塑相关的上升咬合载荷可能导致固定板疲劳断裂，并可能导致严重的骨质吸收。
本研究提出了一种有效的方法，可以更真实地预测组织重塑条件下假体装置的疲劳寿命。预计可为衍生出最佳的患者特异性假体装置设计提供指导，以更好地确保其耐久性。
