Geng J P, Ma Q S, Xu W, Tan K B C, Liu G R
Department of Dentistry, China Medical University Huayu Hospital, Shaoxing, China.
J Oral Rehabil. 2004 Mar;31(3):233-9. doi: 10.1046/j.0305-182X.2003.01213.x.
The purpose of this study was to determine the optimal thread form configuration for an experimental stepped screw implant. Two-dimensional finite element analysis was applied to model the experimental stepped screw implant in a standard cross-section of the posterior human mandible digitized from a CT-generated patient data set. Four different thread form configurations: v-thread (V), thin-thread (T), and two square-thread forms of 0.24 mm (S1) and 0.36 mm (S2) thread width were compared under oblique load in normal cortical bone condition. The support-type constraint position changed from middle to the base of the bone segment. In middle support-type constraint position only the thin-thread (T) model demonstrated significantly different stress distribution from the other three models, however, in base support-type constraint position T and S1 models demonstrated significantly different stress distribution from the other two models. The results implies that v-thread (V) or large square-thread (S2) are optimal thread form for the experimental stepped screw implant. While, minimal support constraints allow clearer differentiation of the stress picture between the different stepped screw types at the trabecular bone-implant interface.
本研究的目的是确定一种实验性阶梯式螺钉种植体的最佳螺纹形态结构。应用二维有限元分析，在从CT生成的患者数据集中数字化的人类下颌骨后部标准横截面中对实验性阶梯式螺钉种植体进行建模。比较了四种不同的螺纹形态结构：V形螺纹（V）、细螺纹（T）以及两种螺纹宽度分别为0.24 mm（S1）和0.36 mm（S2）的方形螺纹，在正常皮质骨条件下承受斜向载荷。支撑型约束位置从骨段中部移至基部。在中部支撑型约束位置，仅细螺纹（T）模型的应力分布与其他三种模型有显著差异，然而，在基部支撑型约束位置，T和S1模型的应力分布与其他两种模型有显著差异。结果表明，V形螺纹（V）或大方形螺纹（S2）是实验性阶梯式螺钉种植体的最佳螺纹形态。同时，最小支撑约束能更清晰地区分不同阶梯式螺钉类型在小梁骨 - 种植体界面处的应力情况。
