|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 pressure 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.