Ti2448分裂型根管桩对上颌中切牙应力分布影响的三维光弹应力分析

目的:研究分裂型设计的低弹性模量Ti2448根管桩对上颌中切牙及其牙周支持组织应力分布影响的三维光弹应力分析。方法:分别制作铸造钴铬合金、Ti2448根管桩各12个,再取两种金属桩各6个切割出裂隙(高度4.5 mm,宽度0.3 mm)。分别制作牙根和牙槽骨的环氧树脂模型,将各部件组合后根据桩钉材料、形态设计与加载方式将模型分为8组。采用三维光弹应力分析法比较两种设计形式的钴铬合金和Ti2448根管桩对上颌中切牙及其牙周支持组织应力分布影响的三维光弹应力的差别。结果:同一种材料不同设计形式桩之间相比,无论是钴铬合金,还是Ti2448,牙槽骨各部位的应力值都是分裂型桩低于不分裂桩,差异均有统计学意义(P<0.05)。4组间应力值相比,各部位均以钴铬合金不分裂型桩最高,钴铬合金分裂型次之,Ti2448不分裂型再次之,Ti2448分裂型最低,各组间相比差异均有统计学意义(P<0.05)。结论:不同弹性模量材料金属根管桩以及其形态设计都对牙根应力分布有明显的影响,弹性模量与牙体组织接近的Ti2448分裂型根管桩可以达到保护牙根防止折裂的效果。

Three-dimensional photoelastic stress analysis of maxillary central incisor roots restored with Ti2448 split cast posts

AIM: To analyze the distribution of three-dimensional photoelastic stress of maxillary central incisor roots restored with Ti2448 split cast posts.METHODS: Twelve Ti2448 and Co-Cr alloy posts were made.Six posts of each alloy were chosen and a split was made on each(H4.5mm,W0.3mm).The 24 photoelastic models of maxillary central incisor roots were divided into 8 groups according to material and loading method.The stress distribution of the roots restored with Ti2448 and Co-Cr alloy posts was analyzed by three-dimensional photoelastic analysis.RESULTS: Split posts of both Ti2448 and Co-Cr groups showed significantly lower stress values than non-split posts(P<0.05).The stress values were as follows: Co-Cr non-split posts>Co-Cr split posts>Ti2448 non-split posts>Ti2448 split posts(P<0.05).CONCLUSION: Post material and post design influence the root stress distribution significantly.Ti2448 cast split posts can protect roots from fracture.