This study aimed to examine the influence of early loading on dynamic changes of bone metabolism around dental implants by using a Fine PET. Two titanium implants were inserted in the right tibiae of Wistar rats. 1 day after insertion, closed coil springs with 4.0 N were applied to the implants. The rats with ^<18>F^- (5mCi/rat) intravenously-injected were scanned by PET scanner at 4, 7, 14, 28 days after load application. Round ROIs were set around the distal implant (right tibia) and at the intact side (left tibia). Longitudinal dynamic changes in bone metabolism were evaluated by examination of the accumulation count of ^<18>F^-at each ROI. The results shows that early loading to the implant initially enhanced the bone metabolism around the implant, however, metabolic activity returned to pre-loading level with time despite a static force being applied to the implants.
