Masticatory movement was investigated by using the simple motion-picture method for 134 students (aged 19-29 years) and 42 school children (aged 11-12 years). Test foods consisted of hard jelly, pectin jelly and agar gel. Bitingforce of the first permanent molar in each subject was measured at the same time. The results were as follows.
1. Mean chewing frequencies increased corresponding to hardness of the test foods.
2. Pectin jelly showed slower mean rate of masticatory cycle than that of the other foods because of the adhesive texture.
3. Masticatory movement of hard jelly showed significantly difference among male and female. These data and mean chewing frequencies demonstrated reproducibility of the method.
4. Sex differences did not appear in the masticatory movement for school children.
5. The biting force of the first permanent molar showed significant difference by sex and age.
6. There was no correlation between biting force of the first permanent molar and masticatory movement.