Inhibition of Alveoloar Bone Loss During Maturation of the Rat

The effects of dichloromethylene diphosphonate (C1₂MDP) on previously described maturational bone loss were quantified in 24 Wistar rats. Four groups of six animals each were treated daily from 18 to 28 weeks of age with a subcutaneous injection of a 0.1, 1.0 or 10mg/kg dose of C1₂MDP or were sham treated with 0.9% NaC1. Prior to sacrifice, all animals were double-labeled with tetracycline. The interdental bone between first and second maxillary molars was evaluated on decalcified stained sections and on undecalcified ground sections by digitizing morphometry. No significant differences in periodontal ligament width, bone height, osteoclast numbers or tetracycline labeled surface were detected. Significantly greater bone area (p<0.01) and bone width (p<0.005), and significantly fewer osteoblasts/mm of bone surface (p<0.001) were measured in rats treated with 10 mg/kg doses of C1₂MDP; and a dose response was demonstrated. It was concluded that C1₂MDP prevented interdental bone loss by inhibiting bone resorption, and that bone formation may have been indirectly reduced through a coupling mechanism.