This study was carried on raths to determine the effects of the analgesics on the osteoclastic activity, taken within the first three days. Appliances developed by ourselves were applied to twenty adult raths which were separated into two groups consisting each ten animals. Daily water to the controls where water containing analgesic to the study group were given. After three days osteoclasts were counted in the interradicular septum of the first molar where the appliance were applied in the sacrificed animals. In the study group the number of the osteoclast were lessened when compared to the control group.

Keywords: Orthodontic tooth movement, Prostocycline, Aspirine