Abstract
This study was undertaken to clarify the effect of changes in the masticatory function of the mandible due to food hardness. Three-week-old male rats of the Wistar strain were divided into the formed food group, the kneaded food group I, kneaded food group II, and powdered food group. The effect of the food was investigated after a period of six weeks.
The results were as follows:
1. The average compressive strengths of the food were 94.32 kg/cm2 for formed food,45.23 kg/cm2 for kneaded food I,14.20 kg/cm2 for kneaded food II, and 0 kg/cm2 for powdered food.
2. Based on Photo-densitometric observation, it was neveared that bone density of the alveolar bone was the highest for the formed food group and decreased in the order of the kneaded food group I, kneaded food group II, and powdered food group.
3. As for mandibular length and ramus height, the formed food group, kneaded food group I, and kneaded food group II showed about the same values. The powdered food group showed lower values.
4. Based on x-ray microanalysis, it was found that in Ca ratio (Ca/[Ca] c) and P ratio (P/[P] c) obtained from the comparison with the controls of the quantitative analysis bypoint analysis of Ca and P in the alveolar bone, the formed food group and kneaded food group I showed about the same values, which were higher than those shown by the kneaded food group II and powdered food group.
5. Fracture strength of the mandible was the highest for the formed food group and decreased in the order of the kneaded food group I, kneaded food group II, and powdered food group.
On the basis of the foregoing findings, changes in the hardness of food were proved to affect the internal structures of the alveolar bone.
