The Quantitative Elucidation of the Correlation Between Bone Growth and Masticatory Function.

本研究旨在探讨咀嚼肌纤维的组织化学特征对大鼠颅面生长的影响。其中一组喂以正常硬度的食物作为对照(A组)，另三组(B-D组)喂以软性食物以诱导低功能活动。B组负重低于A组，C组为粉剂，D组为自制，实验周期为29周，从3周龄开始。(结果)1.C组体重下降至实验第4周结束。2.下颌骨长度线性测量值仅C组减少，C组和D组下颌高度线性测量值均减少。最重要的发现是下颌肌垂直生长的最大影响时期与咬肌和颞肌变化的最大影响时期之间的相关性。提示改变下颌肌纤维负荷的组织化学特征可以抑制下颌骨的垂直生长。

The purpose of this study was to elucidate the influence of histochemical characteristic of masticatory muscle-fibers on craniofacial growth in rats.One group fed a normal hardness food as a control (group A), while another three groups (group B-D) fed a soft diet in order to induce a low functional activity. Group B was less loaded than group A, group C was powder, and group D was our own making.The experimental period was 29 weeks and started from 3-week-old rats.(Results) 1. Body weight was decreased in group C till the end of 4th weeks of the experimental period. 2. Decrease in linear measurement of mandibular length was found only in group C and decreasing linear measurement of mandibular height was found in group C and group D.Comparing group A with group D by ATPase staining method gave attention of the histochemical characteristic of muscle-fibers in masseter and temporalis muscles. It showed changes of fibers area composition and decrease of fiber diameter.The most important finding was the correlation between the most affected period of mandibular vertical growth and most affected period of changes of masseter and temporalis muscles.Changing in the histochemical characteristic of muscle-fibers loading on the mandible was suggested to suppress mandibular vertical growth.