Effects of fluoride on osteoclastic bone resorption during experimentally moved rat molars

Kim, Do Hoon; Moon, Yoon Shik; Ko, Jea Seung; Kim, Hyun Man

Abstract

Orthodontic tooth movement requires remodelling of periodontal tissues, especially alveolar bone. Fluoride is known to be a potent inhibitor of osteoclastic bone resorption. The purpose of this study was to examine the effects of a consumption of fluoride on osteoclast numbers appearing on the pressure side of alveolar bones at experimental tooth movement. 40 male rats were exposed to 0, 10, 25 mg/kg/day of sodium fluoride(NaF) in their drinking water for up to 60 days. Orthodontic appliance were activated to mesially tip maxillary first molar with 50-70g. The rats were sacrificed at 1, 2, 4 days after initial activation. The number of osteoclast was counted in a 450 x 700 micrometer2 area interradicular septum on the pressure side of the maxillary first molar. The results were as follows, 1. There was significantly different osteoclast number between control group and 25 mg/kg/day group at all measured time. (p<0.05) 2. There was significantly different active bone-resorption area between control group and 25 mg/kg/day group except at 96 hours post activation. (p<0.05) 3. There was slight reduction of active bone-resorption area in control group from 48 hours to 96 hours but in both 10 mg/kg/day group and 25 mg/kg/day group a slight increase was observed from 48 hours to 96 hours.