EFFECTS OF SODIUM-FLUORIDE AND ALENDRONATE ON THE BONE-MINERAL IN MINIPIGS - A SMALL-ANGLE X-RAY-SCATTERING AND BACKSCATTERED ELECTRON IMAGING STUDY

Sodium fluoride (NaF), which stimulates bone formation, and bisphospho nates, which reduce bone resorption, are both used in the treatment of osteoporosis, and are binding to bone mineral, In this study, using s mall-angle X-ray, scattering and backscattered electron imaging, we an alyzed the bone mineral in the vertebrae of minipigs treated with fluo ride, with the bisphosphonate alendronate (ALN), or with vehicle, All specimens were investigated blindly, A slight increase in the average thickness of the mineral crystals as well as changes in the structure of the mineral/collagen composite were found in the case of fluoride-t reated animals, No differences were found between ALN-treated animals and controls, The changes produced by fluoride are in the same directi on as seen in bones from patients treated with NaF, albeit much smalle r, They also correlate quantitatively with the reduction in biomechani cal properties of bone in fluoride-treated minipigs found in an earlie r study with the same animals, These findings suggest that small chang es in the structure of the mineral/collagen composite in bone may cons iderably affect its biomechanical properties, It also emphasizes the d elicate balance between the increase of bone mass and deterioration of bone material properties for the effect of fluoride on the biomechani cal properties of bone.