X-ray fluorescence measurement of bone calcium, phosphorous and fluoride in a rat osteoporosis model

The fluoride (F), calcium (Ca) and phosphorous (P) content in two parts of the bone mandible, lumbar spine and femur of rats fed a low mineral diet and corresponding controls were determined by X-ray fluorescence. The anterior part of the mandible, including teeth was labeled as part I while the posterior part, including the mandibular head but excluding the teeth was designed as part II. The bone Ca, P and F content of part I was the same for the experimental and control groups. The Ca, P and F content of part II was decreased in the low-mineral diet group (p < 0.01). The values for F were considerably lower than in the controls. The lumbar spine and femur were used as whole bones and showed a significantly lower values for the three elements measured in the experimental group (p < 0.01). Stress or other stimuli from mandibular movement and occlusal force may be involved in preventing bone density decline, while density loss could be a result of lower physical stimulation, which may exert a greater effect than the level of fluoride in bones. It is possible that the absence of significant difference in fluoride levels in part I of the mandible may have been caused by its accumulation in teeth.