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背景:种植体型牙槽嵴牵张器的初期稳定性取决于骨-牵张器界面适当的应力分布,了解植入初期的生物力学改变有助于提高种植体型牙槽嵴牵张器的临床成功率。目的:通过有限元法了解骨质结构对牵张初期应力分布和牵张器、骨段变形情况的影响。方法:利用CAD软件绘制由输送段和基段组成的牵张器模型(长11mm,直径3.7~4.1mm),同一软件绘制4个下颌骨节段模型模拟4类不同骨质的下颌骨。装配后导入ANSYS软件形成由10079~11456单元和17299~20101节点构成的有限元模型,利用该系列有限元模型分析松质骨、密质骨的应力改变和输送骨段、牵张器的变形情况。结果与结论:最大应力均出现在输送骨段,随骨质量下降而增大;骨最大变形出现在输送段边缘,随着骨质量下降而增大;牵张器的下沉也随着骨质量的下降而增大。结果表明随着骨质量的下降,最大应力与变形均明显增大。骨弹性模量的下降将增大牵张成骨失败的风险。
BACKGROUND: The initial stability of the implant-type alveolar ridge distractor depends on the appropriate stress distribution at the bone-distractor interface. Understanding the biomechanical changes at the initial implantation stage can improve the clinical success of implant-type alveolar ridge distractor rate. OBJECTIVE: To understand the effect of bone structure on the initial stress distribution and the deformation of distractor and bone segments by finite element method. Methods: A distractor model (length 11mm, diameter 3.7 ~ 4.1mm) composed of the delivery segment and the base segment was drawn by using CAD software. Four mandible segments models were drawn by the same software to simulate the mandible of four different types of bone. After the assembly, ANSYS software was imported to form a finite element model consisting of nodes 10079 to 11456 and nodes 17299 to 20101. The finite element model of the finite element model was used to analyze the stress changes of the cancellous bone and the dense bone and the deformation of the distractor . RESULTS AND CONCLUSION: The maximum stress appeared in the delivery bone segment and increased with the decrease of bone mass. The maximum bone deformation occurred at the edge of the delivery segment and increased with the decrease of the bone mass. The distraction of the distraction device also increased with the bone mass The decline and increase. The results show that as the bone mass decreases, the maximum stress and deformation are significantly increased. A decrease in bone modulus will increase the risk of distraction osteogenesis.