Study on Masticatory System Development, by Observing Growth, Function and Eating Behavior as Indicators.

本研究试图从形态学、功能和行为三个方面建立咀嚼系统的定量发展量表。1995年，在回顾前人研究的基础上，选择了几个指标来评价婴幼儿咀嚼系统的形态、功能和行为发育。很少有衡量儿童饮食行为或能力的指标。因此，建立了一个衡量饮食行为进步的标准尺度——“饮食指数”。1996年对横断面数据进行分析，考虑指标的特征，检验指标之间的相关性。1997年，对形态学数据（口腔检查与测量）、功能数据（咬肌活动肌电图、咀嚼效率、咬合力）、行为数据（进食指数、观察进食行为）进行纵向分析。随着年龄的增长，牙弓尺寸增大，发育空间突出，咬肌活动幅度增大，咀嚼节奏稳定，咀嚼效率、咬合力和进食指数增加。这些指标之间存在显著的相关性。通过主成分分析，将这些指标组成发育变量。在出生后的两年内，观察到个体之间存在很大差异。特别是出生后18个月，功能指标不可靠。然而，有人认为2、3岁时的这个变量（发育变量）可以预测5、6岁时的进一步发展。

It was attempted in this study to establish a quantitative developmental scale of masticatory system approaching from morphological, functional and behavioral aspects. In 1995, the previous studies were reviewed and several indices were selected to evaluate morphological, functional and behavioral development of the masticatory system in infanthood and childhood. There were few indices to scale eating behavior or ability for children. Thus, a standard scale for evaluating the progress of eating behavior, 'Eating food index' was established. In 1996, the crosssectional data was analyzed to consider characters of index and test correlation among indices. In 1997, morphological data (dental examination and measurement), functional data (EMG of masseter muscle activity, chewing efficiency, and bite force), behavioral data (eating food index and observing eating behavior) was analyzed longitudinally. Dental arch size became bigger, developmental space become prominent, amplitude of masseter muscle activity increased, chewing rhythm became stable, chewing efficiency, bite force and Eating food index increased with ages. These indices were related each other significantly. Developmental variable was composed from these indices by principal component analysis. During two years after birth, large variance within individuals were observed. Specially, during eighteen months after birth, functional indices were not reliable. However, it was suggested that this variable (developmental variable) in two or three years old could predict further development in five or six years old.