The intervention
WEST
The intervention was an injection of i-PRF on one of the extraction sides in a predetermined moment of the standardized orthodontic treatment, which comprised; fixed orthodontic appliances with MBT.022 inch slot (Votion, Ortho Technology, West Columbia, SC, USA), initial archwire sequence was: 0.014-in NiTi (or 0.016-in NiTi depending on the amount of crowding), 0.016*0.022-in NiTi, and, 0.017*0.025-in NiTi; extraction of the maxillary first premolars just before the insertion of 0.019*0.025-in SS archwire; canine retraction was achieved with closed nickel-titanium coil springs with 150 g of force per side (Fig. Canine retraction using NiTi closed coil springThe preparation along with the application and post-application of the i-PRF