CRANIOFACIAL BONE REMODELING IN GROWING RATS FED A LOW-CALCIUM AND VITAMIN-D-DEFICIENT DIET AND THE INFLUENCE OF MASTICATORY MUSCLE FUNCTION

Fifty-two male growing rats were randomly divided into three groups. T he first group (n = 18) received a hard deficient diet, and the second (n = 18) a soft deficient diet The control group (n = 16) was fed the normal hard diet. Al the beginning and in the middle of the 28-day ex perimental period oxytetracycline was injected. Two representative cor onal sections of the snout and the corresponding contact microradiogra phs were analyzed. The bone mass of the premaxillary and nasal bones s eemed to be less in the two deficient diet groups than in the normal o ne, due to an increased endosteal bone resorption and decreased bone f ormation. No difference in the bone apposition rate and pattern could be seen between the deficient hard and soft diet groups, except in the dorsal part of the premaxilla, where the bone formed in the first hal f of the experiment was markedly more resorbed in the deficient soft d iet group during the remaining period than in the deficient hard diet group. The morphology of the sutures was influenced by the altered fun ction, since the sutural space became narrower, and premature oblitera tions of the internasal suture were observed in the deficient soft die t group. In conclusion, poor bone quality was observed in the skull of rats fed a low-calcium and Vitamin-D-deficient diet, with less bone m ass than in normal conditions. Masticatory function was a significant factor influencing bone remodeling and sutural growth even in situatio ns in which a metabolic bone disturbance exists.