骨皮质厚度及植入角度对支抗种植钉影响的三维有限元分析

Effect of cortical bone thickness and insert angle on primary stability of orthodontic miniscrews with three dimensional finite element

目的:探讨不同骨皮质厚度和不同植入角度对支抗种植钉应力分布的影响及位移变化。方法:建立简单的颌骨及支抗种植钉的三维有限元模型,在不同的骨皮质厚度为0.5mm-3mm和不同的植入角度30°-90°下分别植入支抗种植钉(直径1.6mm、长8mm),在支抗种植钉的头部施加200g力,力的方向与骨面平行,得到模型中的应力和位移,并进行分析。结果:模型中颌骨最大应力均发生在支抗种植钉的颈部,集中分布在1mm的深度范围内。随着骨皮质厚度的增加骨皮质应力减小,当厚度为0.5mm时骨皮质应力较大,从21.00MPa(植入角度70°)到37.88MPa(植入角度30°);骨皮质厚度为1mm时(除外植入角度为≤50°)应力<28MPa。植入角度对骨皮质应力变化影响较大,植入角度为60°、70°时应力较小。颌骨最大位移发生在受支抗种植钉拉压的两侧,支抗种植钉最大位移在其顶部,当骨皮质厚度为0.5mm时,支抗种植钉的位移最大,当骨皮质厚度≥1mm时,骨皮质厚度的变化对位移的影响不显著,植入角度为70°时支抗种植钉位移最小。结论:骨皮质厚度会影响骨皮质和骨松质的应力,临床植入支抗种植钉时应该避开骨皮质较薄的区域,植入区域骨皮质厚度应≥1mm。避免过陡的植入角度(≤30°),当植入角度为70°时支抗种植钉的位移最小,可获得较好的初始稳定性。

Objective:The purpose of this study was to analyze the impact of cortical bone thickness and insert angle on primary stability of orthodontic miniscrews. Methods: The three dimensional element models of bone and miniscrew (1.6× 8mm) were build up, they were designed with different cortical bone thickness from 0.5mm to 3mm and different insert angle from 30°to 90°. A traction force of200g was applied to the head ofthe miniscrew paralleling to the bone surface. The stress distribution and displacement under e...