螺纹旋转角度和密度对种植体初期稳定性影响的三维有限元研究

目的利用三维有限元模型研究种植体螺纹的旋转角度和密度对种植体初期稳定性的影响。方法建立即刻负载的5种种植体三维有限元模型（0．8mm、1．6mm和2．4mm螺距单螺纹种植体以及双螺纹和三螺纹种植体），进行垂直和水平加载，分析5种种植体颈部和根部的相对位移。结果在3种不同螺距的单螺纹种植体中，垂直加载时0．8mm螺距单螺纹种植体颈部和根部的综合相对位移最小（分别为1．600μm和1．199μm），2．4mm螺距单螺纹种植体颈部和根部的综合相对位移最大（分别为2．451μm和2．019μm）；在螺纹密度相同、旋转角度不同的3种种植体中，0．8mm螺距单螺纹种植体颈部和根部的综合相对位移最小，三螺纹种植体颈部和根部的综合相对位移最大（分别为1．994μm和1．602μm）；在螺纹旋转角度相同、密度不同的种植体中，双螺纹种植体颈部和根部的综合相对位移（分别为1．913μm和1．495μm）均比1．6mm螺距单螺纹种植体（分别为2．412μm和1．799μm）小，三螺纹种植体颈部和根部的综合相对位移均比2．4mm螺距单螺纹种植体小。结论随着种植体螺纹螺距的增加，种植体对抗垂直载荷的能力减弱；随着种植体螺纹旋转角度的增加，种植体对抗垂直载荷的能力减弱；随着种植体螺纹密度增加，种植体对抗垂直载荷的能力增加。

Influence of helix angle and density on primary stability of immediately loaded dental implants: three-dimensional finite element analysis

OBJECTIVE: To analyze effects of different thread helix angles and densities on the primary stability of immediately loaded implants using the three-dimensional finite element model analysis. METHODS: Five models of three-dimensional finite element (0.8 mm, 1.6 mm, 2.4 mm, double-threaded, and triple-threaded) were created using the commercial codes of Pro/E software, Hypermesh software, and ABAQUS software. In conditions of horizontal and vertical loading, the micromotions of the finite element models with different thread helix angles and densities were computed with ABAQUS software. RESULTS: Concerning different thread helix angles, the micromotion of single-threaded implant was the minimum and that of the triple-threaded was the maximum with vertical and horizontal loading. The micromotion of doubled-threaded implant was the minimum compared with thread pitch 1.6 mm and the micromotion of triple-threaded implant was the minimum compared with thread pitch 2.4 mm with vertical and horizontal loading. CONCLUSIONS: The thread helix angle and density of implants can greatly affect the vertical interfacial micromotion. With increasing thread pitchs, the resistance of implant to vertical load is weakened; with increasing thread helix angle, the resistance of implant to vertical load is weakened; with increasing thread density, the resistance of implant to the vertical load is weakened.