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目的微型种植体颈部螺纹不利于骨界面应力分布,本研究目的是评价正畸载荷下种植体无螺纹颈部高度和锥度同时连续变化下骨组织内应力分布。方法建立微种植体-骨组织三维有限元模型,种植体颈部无螺纹高度变化为0~3 mm,锥度变化为0°~45°,种植体给以2N的载荷,观察颈部无螺纹高度和锥度同时变化对骨界面Von-Mises应力及位移峰值的影响,并进行应力敏感度分析。结果颈部无螺纹高度为1.5mm时,随着颈部锥度的增加,皮质骨内Von-Mises应力峰值降低82%,位移峰值降低59%,松质骨应力峰值降低47%,位移峰值降低14%。颈部锥度为22.5°时,随着高度的增加,皮质骨应力峰值和位移峰值明显降低,但颈部无螺纹部分一旦超出皮质骨厚度范围,松质骨内应力峰值和位移峰值显著增高。结论种植体颈部无螺纹高度和锥度对骨界面应力分布有显著影响。颈部无螺纹高度比锥度对骨内应力水平影响更大。建议使用具有一定颈部锥度的种植体,或将传统螺纹种植体适当增加植入深度,使螺纹起始处位于皮质骨厚度范围内。
Objective The purpose of this study is to evaluate the stress distribution in the bone tissue under the condition of continuous and non-threaded neck height and taper with orthodontic load. Methods The three-dimensional finite element model of micro-implant-bone tissue was established. The non-thread height variation of the implant neck was 0-3 mm, the taper change was 0 ° -45 °, and the implant was loaded with 2N. The neck non-thread height And taper on the bone interface Von-Mises stress and displacement peak, and stress sensitivity analysis. Results With the increase of neck taper, the peak value of Von-Mises stress in cortical bone decreased by 82%, the displacement peak decreased by 59%, the peak stress of cancellous bone decreased by 47% and the displacement peak decreased by 14% %. When the neck taper was 22.5 °, the peak stress and peak displacement of cortical bone were significantly decreased with the increase of height. However, the stress peaks and peak displacement of cancellous bone were significantly increased when the non-threaded part of the neck exceeded the cortical thickness. Conclusion The non-threaded height and taper of the implant neck have a significant effect on the stress distribution of the bone interface. Neck non-thread height than taper on the stress level of bone greater impact. It is recommended to use an implant with a certain neck taper, or to increase the implant depth with a traditional thread implant so that the start of the thread is within the cortical thickness.