Study on the influence of masticatory movement on the growth and development of the mandibular bone-Fusion of genetic and mechanical analyses-

目的研究下颌骨的生长发育受咀嚼运动的影响。因此，为了明确咀嚼对颌骨的影响，在研究1中研究了咀嚼对下颌骨形态和基因表达变化的影响，在研究2中比较了不同面部模式中每个区域的皮质骨厚度和骨密度，以收集力学分析所需的基础数据。材料和方法在研究1中，使用3周龄的ICR小鼠，实验组包括喂食硬食物的组、喂食软食物的组和交替喂食硬食物和软食物的组。实验开始后1周和4周，用micro-CT、H。E.用增殖细胞核抗原（PCNA）检测软骨细胞增殖能力。此外，使用激光显微切割方法观察基因表达的变化，并定量检测G 关于我们 使用实时PCR方法评估关于软骨生长的基因表达。在研究2中，皮质骨的厚度和密度在3种类型的面部模式进行了测量，使用锥形束CT.ResultsStudy 1：一个显着的差异，下颌骨形态之间的软，硬的食物组。组织学上，硬食物组髁突软骨中肥大的软骨细胞层明显增厚。软骨细胞的增殖能力在硬质食物组中最低。此外，在基因表达水平的变化方面，与软骨细胞的钙化和最终分化相关的基因的表达量在硬质食物组中显著增加。研究2：3种脸型的皮质骨厚度和密度没有显著差异。然而，dolico的面型表现出较低的值的骨密度和厚度的皮质骨在所有areas.Discussion和ConclusionOur实验表明，咀嚼运动的影响，下颌髁突软骨细胞的分化，提示髁突软骨生长和下颌骨形态的显着影响。此外，还表明咀嚼肌的特性可能会改变面部骨骼形态。少

PurposeIt has been reported that mandibular bone growth is greatly influenced by mastication. Therefore, to clarify the influence of mastication on the jaw bone, its influence on changes in mandibular bone morphology and gene expression was investigated in study 1, and the thickness and bone density of the cortical bone in each area were compared among different facial patterns in study 2 to collect basic data necessary for mechanical analysis.Materials and MethodsIn study 1, using 3-week-old ICR mice, the experimental groups comprised a group in which hard food was fed, that in which soft food was fed, and that in which hard and soft foods were alternately fed. One and 4 weeks after initiating experiments, mandibular bone morphology was measured using micro-CT, H. E. staining was performed, and the proliferation ability of chondrocytes was evaluated using PCNA. Furthermore, changes in gene expression were observed using the laser microdissection method, and the quantitative level of g … More ene expression regarding cartilaginous growth was evaluated using the real-time PCR method. In study 2, the thickness and density of the cortical bone in 3 types of facial patterns were measured using cone-beam CT.ResultsStudy 1 :A marked difference in mandibular bone morphology was noted between the soft and hard food groups. Histologically, the hypertrophic chondrocyte layers in the mandibular condylar cartilage were significantly thicker in the hard food group. The proliferation ability of chondrocytes was lowest in the hard food group. Furthermore, regarding changes in the level of gene expression, the expression of genes related to the calcification and final differentiation of chondrocytes was significantly higher in the hard food group.Study 2 :No significant differences in the thickness and density of the cortical bone were detected among the 3 types of facial patterns. However, the dolico facial type showed low values for the bone density and thickness of the cortical bone in all areas.Discussion and ConclusionOur experiments revealed that masticatory movement influenced the differentiation of the mandibular condylar chondrocytes, suggesting a marked influence on condylar cartilaginous growth and mandibular bone morphology. Furthermore, it was also suggested that the characteristics of the masticatory muscles may change facial skeletal morphology. Less