The Investigation of the effect of low-dose aspirin on experimental orthodontic tooth movement in rats

THE INVESTIGATION OF THE EFFECT OF LOW-DOSE ASPIRIN ON EXPERIMENTAL ORTHODONTIC TOOTH MOVEMENT IN RATS : SUMMARY The effect of low-dose aspirin (0.5 mg/ml ) on experimental orthodontic tooth movements in 30 male rats (Wistar albino) weighing 200±20 gr at 90±10 days old investigated in Control group (no application), Plasebo group in which orthodontic forces were applied and distil led water was given and Aspirin group in which orthodontic forces were applied and low-dose aspirin was administered. The appliance modified from other investigators' appliances and 20 gr force directed to incisors on lateral direction was used. Rats were sacrified on the 24 th day and their premaxilla s decalcified in EDTA solution and serial sections were taken on frontal plane. No adverse effect of appliance, oro-gastric tube and orthodontic tooth movement were seen on soft tissues during experimental period. High remodelling activity and numerous background multinuclear osteoclasts were determined in Control group (especially on anterior region). With the effect of orthodontic forces resorption in pressure areas and apposition in tension areas were-87- observed. Significant resorptions of lateral alveolar bone plate on experimental groups (especially more remarkable in Aspirin group) were seen due to the anatomic structure of rats on alveolar bone, anatomic position of upper incisors, long duration of experiment and the activation of appliance more than once. Cemento-dentinal resorptions, hyalinized areas and ankylosis were noticed in the areas of alveolar bone on which pressure became dense related to the orthodontic forces. The proliferation of periodontal cells, vascular activation, the granulation tissue and interstitial hemorrhage were observed. The increment of the number of multinuclear osteoclasts and Howship' s lacunae were also determined. These findings were more severe in Aspirin group than the Plasebo group. The rate and the amount of orthodontic tooth movement increased statistically more significantly (* p<0.05) in Aspirin group compared to Plasebo group. There were no significant differences between Plasebo and Aspirin groups related to serum Ca. and P. levels and histopatologic appearance of rats stomach and bone, but minimal degenaration and hemorrhage were noticed during the histopatologic investigation of kidney and liver. It is concluded that low-dose aspirin increased significantly the number of multinucleer osteoclasts, Howship' s lacunae, osteoclastic bone resorption and the rate of orthodontic tooth movement.