The Effect of Celecoxib on Orthodontic Tooth Movement and Root Resorption in Rat

Inhibition of prostaglandin (PGs) production leads to decrease in orthodontic tooth movement (OTM). It is not known whether inhibition of cyclooxygenase-1 (COX-1) or cyclooxygenase-2 (COX-2) is the key mechanism for this effect. In this study، the effect of celecoxib، a highly-selective COX-2 inhibitor، was investigated on OTM in rats. Four groups of male rats (seven animals in each goup) were used in the study. A 5mm-long nickel-titanium closed-coil spring was ligated between the right maxillary incisor and the first molar of each rat to deliver an initial force of 60g. All four groups recieved orthodontic appliances، group 1 received no injections، group 2 received celecoxib injections (0. 3 mg in 0. 1 ml saline solution)، group 3 recieved normal saline injections (0. 1 ml saline solution)، and group 4 recieved needle penetration without injecting any solution. The local injections were carried out every 3 days for 18 days. All injections were subperiosteal and given in the upper right first molar mucosa. The animals were sacrificed 21 days after appliance insertion and OTM was measured. In the animals treated with celecoxib a statistically significant decrease in OTM was observed compared with the other groups. Histological findings revealed that osteoclast count was significantly lower in group 2 compared with the other groups (P<0. 05). The amount of root resorption showed a slight، but nonsignificant decrease in group 3. This study suggests that celecoxib decreases OTM and osteoclast count. This might be the result of COX-2 enzyme inhibition and subsequent decrease in prostaglandin production.