Effects of Bisphosphonate on the Tooth and Alveolar Bone Growth in Rats

Kim, Hyun Jin; Kim, Min Seok; Lee, Mi Ra; Jung, Ji Yeon; Kim, Won Jae; Kim, Sun Hun; Lee, Eun Ju

Abstract

Eruptive movement of the tooth germ accompanies the resorption and formation of the surrounding alveolar bone. Bisphosphonate has effects on osteoclasts to inhibit bone resorption, being currently used for the treatment of bone disease such as osteoporosis. This study was conducted to elucidate effects of bisphosphonate on tooth eruption in growing rats. Alendronate, a derivative of bisphosphonate, was injected into newborn rats at the concentration of 0.5 mg/kg and 2.5 mg/kg for 3, 7 and 10 days. The incisor and molar teeth normally erupted at postnatal 22 days in the saline-treated control group, whereas no teeth could not be seen in both groups of the alendronate treatment. No conspicuous histological changes could not be found in the teeth germs in the alendronate treated rats. The number of osteoclasts in both the first and the second molars was maximum on the postnatal day 10. The number of osteoclasts significantly increased by both 3 and 7 days of alendronate treatment (p< 0.01). But the number significantly decreased by 10 days of alendronate treatment in both concentrations (p< 0.01). The size of osteoclasts was not different between the control and alendronate groups. Thus, these results suggest that bisphosphonate acts on osteoclast formation to inhibit bone resorption and subsequent tooth eruption.