Different methods have been introduced for acceleration of orthodontic tooth movement. Because it is less invasive with minimal side effects, Platelet rich plasma (PRP) is one of the most recently used techniques. To evaluate the effect of submucosal injection of PRP on maxillary canine retraction and to report any associated pain. Twenty patients were selected and randomly assigned in a split mouth trial designed to obtain PRP injection in one side (study side) while the other received no injection and served as a control. Before canine retraction, injection was done and not repeated again. After extraction, leveling and alignment; canine retraction was done on 0.017x0.025-inch stainless steel arch wire with closed coil spring from the canine hook to a mini-screw inserted between upper second premolar and first molar on both sides. The study duration was 4 months. Alginate impression was taken before canine retraction and every month for four months. Data was obtained from digitized models to measure the amount of canine retraction. Pain assessment was carried out by visual analogue scale (VAS). The canine retraction rate in the study side was faster than the control side with a statistically significant difference (P<0.05) in all the four months of the study duration. The total distance travelled by the canine was greater in the study side with a statistically significant difference (P=0.022). Higher pain levels were observed in the study side. Submucosal injection of PRP is a minimal invasive and safe approach for accelerating canine retraction and reducing overall treatment time.
