Changes of masticatory function and biomechanical behavior in growing Mandible.

下颌骨生长过程中咀嚼功能和生物力学行为的变化。

• 批准号: 07838036
• 负责人: MAKI Koutaro
• 金额: $ 1.41万
• 依托单位: Showa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07838036/
• 关键词: Bone Density; Mechanical Stress; Masticatory System; Computed Tomgraphy; Finite Element Method; 機能的刺激; バイオメカニクス; 顎骨; 成長発育; 咀嚼; FEM

The purpose of this study was to investigate the age-related changes in the bone density distribution and to clarify the mechanism of mandibular deformity using 3-dimensional quantitative CT (3DQCT) and a 3-dimensional Finite Element Method (3DFEM).Forty-seven individuals with skeletal deformity and twenty normal subjects (6 to 27 years old) were evaluated.The results obtained from the 3-dimensional abservation of bone density and the FE analysis were as follows : Most cases of deformed mandibles under 18 years of age showed high-density deviation which coincided with the morphological displacement. However, in subjects more than 20 years old, high-density areas were arranged symmetrically against the morphological deformation. The distribution of equivalent (mieses) stress generated by muscle loading coincided with the bone density. In normal subjects and deformed subjects over 20 years old, symmetrical stress distribution was observed. However, in deformed mandibles under 18 years old, stress distribution was biased toward the affected side.Based on this comparison of normal and deformed subjects, the mechanical stress generated by masticatory muscles affects the distribution of mandibular bone density and leads to morphological changes in growth. The skeletal deformity which appeared during postnatal growth was caused by imbalanced mastication. However, after condylar growth was complete, mandibular bone density adapted to its imbalanced mechanical environment. These findings suggest that preventive, orthodontic treatment, such as eliminating the functional interference of the malocclusion at an early stage, should give successful results.

本研究应用三维定量CT（3DQCT）和三维有限元法（3DFEM）研究下颌骨骨密度分布的增龄性变化，探讨下颌骨畸形的发生机制骨密度三维测量和有限元分析结果如下：18岁以下的畸形下颌骨多表现为高密度偏移，与形态移位相吻合。然而，在20岁以上的受试者中，高密度区域相对于形态变形对称排列。肌肉负荷产生的等效应力分布与骨密度分布一致。在正常人和20岁以上的畸形人中，观察到对称的应力分布。然而，在18岁以下的畸形下颌骨中，应力分布偏向于患侧，基于正常和畸形受试者的这种比较，咀嚼肌产生的机械应力影响下颌骨骨密度的分布，并导致生长的形态变化。出生后出现的骨骼畸形是由于咀嚼不平衡造成的。然而，当髁状突生长完成后，下颌骨密度适应其不平衡的力学环境。这些结果表明，预防性的正畸治疗，如消除功能干扰的错在早期阶段，应该取得成功的结果。