成長期ラットの虚弱下顎骨における食餌療法の影響に関する実験的研究 : 骨塩量とセファロ分析による形態計測

抄録

Bone mineral content increases with age in developing children and it has been reported that peak bone mass is obtained around 17-20 years of age. Therefore, the accumulation of adequate bone mass in this period is a key determinant in prevention of osteoporosis. Rats aged 5 weeks, corresponding to schoolchildren in human, were used in the present study. The effects of dietary therapy rich in calcium content on mandibular osteoporosis produced by calcium deficiency were investigated, using computed X-ray densitometry and cephalometry. The results were as follows. 1. Weight Calcium deficient animals exhibited significantly lower weight than control animals 4 weeks post-experimentally (p<0.05). The difference disappeared, however, after the animals were fed standard diet for 8 weeks. 2. Densitometry No significant differences were identified between the control and experimental groups in bone density of mandibular angle, condylar and coronoid processes. 3. Cephalometry A. Coordinate analysis The experimental groups exhibited significantly lower values than control group in mandibular angle, condylar and coronoid processes (p<0.05). However, no significant differences were found between the experimental and control groups in mandibular body and alveolar process. B. Distance measurement The experimental groups showed significantly shorter mandibular border, ramus, and coronoid process than the control animals (p<0.05). C. Area measurement The experimental groups showed significantly less area of mandibular angle and condylar process than the control animals (p<0.05). From the foregoing results, dietary therapy rich in calcium content showed a nagetive result for recovery of mandibular osteoporosis in school childhood with cephalometric investigation, but gave a positive result measured by computed X-ray densitometry.