Strain at Root Cervical Portions of Maxillary Premolars by Occlusal Loading. Effects of Loading Point and Direction.
Strain at Root Cervical Portions of Maxillary Premolars by Occlusal Loading. Effects of Loading Point and Direction.
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咬合加载导致上颌前磨牙根颈部分的应变。
DOI：
10.2504/kds.55.63
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
K. Miyake
中科院分区：
文献类型：
--
作者：
K. Miyake
牙齿的形状和结构与咀嚼和吞咽有关。在形态学上，前臼齿可以被认为是犬齿和臼齿之间的“中间”或“过渡”形式。前磨牙，尤其是第一前磨牙，常因咬合力的作用而发生硬组织损伤。因此，本研究采用应变片测量上颌前磨牙根颈面的应力，研究咬合加载点和方向对上颌前磨牙根颈面应力产生的影响。测量了离体上颌第一和第二前磨牙的近中面和远中面，每个规定的咬合面。载荷的压缩分量通常产生轴向缩短和桶形变形，以及向载荷侧的侧向弯曲。应变值随加载点距离测量区域的增加而增大。第二，在环氧树脂复制的第一前磨牙模型上，以-10 °、0 °、10 °和20 °的角度，在矢状面内近中施加7 kg的载荷。另外，对柱状环氧树脂模型进行了同样的实验。过度的近中倾斜似乎使牙齿向近中方向弯曲，并在加载的对侧产生异常的拉应力。第三，在环氧树脂模型上同时施加7 kg的载荷于牙合面的3个点（腭尖、近中、远中边缘嵴）。上述结果表明，如果牙形和加载方向因磨损而发生变化，即使咬合力大小足够，不平衡加载也会对牙齿外观产生一定的影响。在此基础上进行咬合重建时，有必要考虑牙齿的形态和咬合方向。
The shapes and structures of teeth are associated with mastication and swallowing. Morphologically, the premolars may be regarded as “intermediate” or “transitional” forms between canines and molars. Lesions of the hard tissues, which might have been induced by occlusal force, are often observed on premolars, especially on first premolars. In the present study, therefore, the effects of the occlusal loading point and direction on the stress generation in the root cervical surface of maxillary premolar were examined using strain gages.In the first experiment, the strains on the four root cervical regions involving buccal, palatal, mesial and distal surfaces were measured for extracted intact human maxillary first and second premolars when one concentrated load was applied perpendicularly to each of the prescribed occlusal surfaces. The compressive component of the load generally yielded axial shortening and barreling, and lateral bending toward the loading side. The strain values increased as the loading point located farther and outer from measuring area. It suggests that the shortening of the crown or outward shifting of occlusal contacts by attrision may have a risk of injuring teeth and periodontal tissues.Second, a load of 7 kg was applied to epoxy resin models duplicating first premolars mesially in sagittal plane at an angle of -10, 0, 10 or 20 degree. In addition, the same experiment carried out for the columnar epoxy resin model. Excessive mesial inclination seemed to make the teeth bend to mesial direction and induce unusual tensile stress on the opposite side of the loading. It was confirmed from the finding that the cervical one-third exhibited a deep depression and the mesial concavity extends from the crown down to the root surface.Third, a load of 7 kg was applied to the epoxy resin model on the 3 points (palatal cusp, mesial and distal marginal ridges) of the occlusal surface at the same time. The compressive strain became smaller than that in 1 point loading.The foregoing results suggest that the imbalanced loading, even though the magnitude of the occlusal force is adequate, may give some effect on the teeth aspects, if the shape of teeth and the directions of loading are varied by attrisions. It is necessary to consider the configuration of teeth and the occlusal direction on this basis in the occlusal reconstruction.
影响因子：
3
作者：
Kinney, JH;Balooch, M;Weihs, TP
通讯作者：
Weihs, TP