摘要
目的 探讨由形态变化产生的根尖主应力变化对颞下颌关节 (TMJ)应力的影响。方法 取光弹法测得的正中载荷作用下 7种型各牙根尖应力参数 ,在所建下颌骨三维有限元模型上加载 ,比较其TMJ应力。结果 (1)髁突前斜面及其表面软骨和关节盘中部主要承受压应力 ,髁突后斜面及其表面软骨和关节盘后部主要承受拉应力 ;(2 )与正常相比 ,平面、远中、部分后牙反、缺牙的TMJ应力均有不同程度变化 ,其中平面的变化最明显。单侧上颌第三磨牙伸长、单侧下颌第三磨牙伸长的TMJ应力变化均不明显。结论 由型改变导致的正中咬合时根尖主应力变化 ,对关节应力性质的影响不明显 ,但对应力大小有一定影响。
Objective To investigate the effects of tooth apical stress changes caused by different types of occlusion on the TMJ stresses. Methods The apical stresses measured from photo-elastic experiments (2 Kg centric vertical loading to seven types of occlusions separately) were applied to the established 3D finite elemental model. The stress distributions on condyle,superfacial cartilage of condyle and TMJ disc were compared. Results (l) The stress on both anterior surface of condyle and its superfacial cartilage and on the intermediate band of disc were mainly compressive,while the stress on both posterior surface of condyle and its superficial cartilage and on the posterior band of disc were mainly tensile ( P <0.01). (2) The values of TMJ stresses of models with flat surface occlusion,distal occlusion,unilateral partial molar teeth cross bite,and occlusion with right second and third molar tooth missing were different to some extent from that with normal occlusion,among which the TMJ stress from the flat surface occlusion differed most significantly ( P <0.01). The TMJ stresses of models with unilateral upper third molar hyper-eruption occlusion and unilateral lower third molar hyper-eruption occlusion did not significantly differ from that with normal occlusion. Conclusions Changes of apical principle stress resulted from different types of occlusions during centric biting have effects to some extent on TMJ stress quantitatively but not qualitatively.
出处
《中华口腔医学杂志》
CAS
CSCD
北大核心
2004年第3期242-244,共3页
Chinese Journal of Stomatology
基金
国家自然科学基金资助项目 (3 93 70 195 )
