第三磨牙伸长对下颌各牙根尖应力分布规律影响的光弹实验研究  

The effects of unilateral hyper-erupted third molar tooth on apical stress distribution of mandibular teeth by photoelastic analysis

作　　者：王景杰[1] 张旻 王美青[1] 张俊华[1] 张渊[1] 

机构地区：[1]第四军医大学口腔医学院,陕西西安710032

出　　处：《牙体牙髓牙周病学杂志》2002年第5期261-265,共5页Chinese Journal of Conservative Dentistry

基　　金：国家自然科学基金资助项目 (3 93 70 195 );高等学校骨干教师资助项目

摘　　要：目的 :探讨单侧上颌或下颌第三磨牙伸长对下颌各牙根尖应力传导规律的影响。方法 :采用透明环氧树脂复制以相同牙列而排成的正常牙合、单侧上颌或下颌第三磨牙伸长的咬合模型各 1副 ,2 .0kg垂直加载 ,切片后投影式光弹仪上观测各牙根尖主应力的大小与方向 ,及其与下颌牙根轴倾角间的关系。结果 :所建 3个 (种 )模型下颌牙根轴倾角无显著差异 ,上颌第三磨牙伸长对侧及下颌第三磨牙伸长侧磨牙的根尖主应力较正常牙合者更偏向远中颊侧 ,应力水平显著升高 (P <0 .0 5 )。而相应另一侧的磨牙根尖主应力方向更偏向近中舌侧。上颌第三磨牙伸长对侧及下颌第三磨牙伸长侧的应力水平均高于正常牙合 (P <0 .0 5 )。结论 :单侧第三磨牙伸长可致牙根尖应力发生改变。AIM: To investigate the effect of unilateral hyper-erupted third molar on the stress distribution to the apical area of mandibular teeth. METHODS: Epoxy resin models of normal occlusion and those with unilateral hyper-erupted maxillary or mandibular third molar tooth were employed to determine the stress distribution features to the apical area under 2.0 kg vertical load. The values and directions of main stress were both measured and analized. The relationship between the long axes inclination of the mandibular teeth and its stress direction was also considered. RESULTS: In occlusion with maxillary third molar tooth hyper-erupted, the main stress of the tooth socket of molar areas in the side with hyper-erupted tooth directed mesial-lingually, while those of opposite side were disto-buccally. But in occlusion with hyper-erupted mandibular third molar tooth, it was just the reversal. While the long axes inclination of mandibular teeth in both occlusions had no difference to the normal. Both of opposite sides of hyper-erupted maxillary third molar tooth and the side of hyper-erupted mandibular third molar tooth showed higher stress values than those of the normal occlusion ( P <0.05) . CONCLUSION: Occlusions with the hyper-erupted third molar tooth had significant effect on the stress distribution to the apical area of mandibular teeth.

关 键 词：第三磨牙伸长 下颌 牙根尖应力分布 影响 光弹实验研究 

分 类 号：R782[医药卫生—口腔医学] R318.01[医药卫生—临床医学]