State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
College of Automation, Harbin Engineering University, Harbin, China.
J Oral Rehabil. 2017 Jul;44(7):526-536. doi: 10.1111/joor.12512. Epub 2017 Apr 27.
The tooth stress elicited by occluding contact represents critical biomechanical information about dental health during chewing. Effects of occlusal contact on tooth stress remain obscure. In this study, a mandibular first molar finite element model was built from CT images. The effects of area size, location and direction of occlusal loading on both tooth and periodontal stresses were analysed. Results showed tooth and periodontal stress had drastically different patterns. Tooth stress value was much higher than periodontal stress value under the same task. Tooth stress concentration area and its value decreased from outside to inside. The Maximum Tooth Stress (MTS) always occurred at the loading site and a larger loading area elicited a smaller MTS value. The variation of MTS was larger when the fossa bottoms were inclined loaded than when the cusp tips were inclined loaded, larger when lingually loaded than when buccally loaded and larger when mesially loaded than when distally loaded. Distal loadings generally induced smaller Maximum Periodontal Stress (MPS) variations than the mesial loadings. These findings indicated exposure of the rational site(s) to occlusal contact should be helpful to achieve proper tooth and periodontal stress, thus to diminish loading associated structure problems.
咬合接触产生的牙力是咀嚼过程中牙齿健康的重要生物力学信息。然而，咬合接触对牙齿力的影响仍不清楚。本研究基于 CT 图像建立了下颌第一磨牙的有限元模型。分析了不同的咬合加载面积、位置和方向对牙齿和牙周组织应力的影响。结果表明，牙齿和牙周组织的应力模式有明显的差异。在相同的任务下，牙齿的力值远高于牙周组织的力值。牙齿的力集中区域及其值从外向内逐渐减小。最大牙力（MTS）始终出现在加载部位，较大的加载面积会产生较小的 MTS 值。当窝底倾斜加载时，MTS 的变化比尖顶倾斜加载时更大，当颊侧加载时比舌侧加载时更大，当近中加载时比远中加载时更大。远中加载通常比近中加载引起的最大牙周组织力（MPS）变化更小。这些发现表明，合理的咬合接触部位的暴露有助于实现适当的牙齿和牙周组织力，从而减少与加载相关的结构问题。
