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目的 :探明正常牙合与重度磨耗牙合两种不同牙合型时各牙根尖应力分布的特征 ,以期揭示牙的解剖形态及牙尖高度的改变对咬合力传导的影响规律。方法 :采用透明环氧树脂复制相同牙排列而成的正常牙合及重度磨耗牙合的下颌模型 ,2 .0kg垂直加载后 ,在国产 40 9-II型投影式光弹仪上观察测量各牙根尖主应力的大小与方向。结果 :近远中方向上 ,重度磨耗牙合下颌牙列中各牙均受到冠向远中、根向近中的转矩力作用。颊舌方向上 ,两种咬合的牙根尖主应力方向相差不显著。重度磨耗牙合各牙根尖应力水平普遍高于正常牙合的相应各牙。结论 :牙齿咬合面正常解剖形态及牙冠高度的丧失对由牙齿向下颌骨传导的生物力有显著影响
OBJECTIVE: To investigate the stress distribution of apical cusp in two different occlusal patterns of normal occlusal and severe occlusal occlusion, in order to reveal the regularity of tooth anatomy and change of cusp height on bite force transmission. Methods: The mandibular model of normal occlusal and severe wear occlusion of the same teeth were made by using transparent epoxy resin. After 2.0kg vertical loading, the root of each tooth was observed and measured on a domestic 40 9-II projection projectile The main stress of the size and direction. Results: In the near and far middle directions, the teeth of severely abraded occlusal mandibular dentition were affected by the torque of the mid-coronoid and the proximal ones. In the buccolingual direction, there was no significant difference in the principal stress between the two kinds of occlusal apical apices. Severe wear occlusion of each tooth root tip stress level is generally higher than the normal occlusion of the corresponding teeth. CONCLUSIONS: The normal anatomy of the occlusal surfaces and the loss of crown height have a significant effect on the biomechanical force transmitted from the teeth to the mandible