|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1998 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1997 : ¥2,800,000 (Direct Cost : ¥2,800,000)
Eicosapentaenoic acid ethyl ester (EPA-E), reduces the production of arachidonic acid and prostaglandins which mediate bone resorption. The purpose of this study was to examine the effect of oral administration of EPA-E on experimental tooth movements in rats. Pour-week-old male Wistar strain rats were divided into the experimental and the control groups, which were administered 1000 mg/kg of EPA-E or 5 % aqueous arabic gum solution intraorally every 24 h, respectively. After 4-week administration of the agents, the maxillary first molars were moved buccally with an initial force of 20 g for periods of 0, 3, 7 or 14 days, in the first experiment. In the second experiment, the maxillary first molars were moved buccally for 14 days, and then the appliance removed. The relapse movement was examined for 3 or 14 days. The agents were continuously administered to the rats during the experimental period. The amount of tooth movement and relapse was measured, and bone resorption on the pressur
e side was evaluated histologically. Additionally, the proximal tibia was examined by bone histomorphometry to evaluate systemic effects of EPA-E.
1. In the experimental group, the amount of tooth movement was 81.8 %, and the amount of relapse was 82.5 % of the controls. The number of osteoclasts and the degree of bone resorption on the pressure side during tooth movement or relapse decreased to nearly 70 % and 80 % of the controls, respectively.
2. In the proximal tibia, osteoclast number and bone resorption of the experimental group decreased to 60-70% and 80% of the controls, respectively. However, no significant differences were found in longitudinal growth, bone formation or trabecular bone structure between two groups.
These results suggest that the oral administration of EPA-E delays experimental tooth movement and decreases relapse movement by inhibiting osteoclastic activity and the subsequent bone resorption.