RANKL concentrations in early orthodontic treatment using passive self-ligating and preadjusted edgewise appliance bracket systems

The receptor activator of nuclear factor κ-B ligand (RANKL) is a cytokine that helps remodel bone by forming osteoclasts. During tooth movement phases, osteoclasts resorb the hyalinization areas of alveolar bone, triggering tooth movement. We determined the differences in RANKL concentrations in early orthodontic treatment between preadjusted edgewise appliances (PEA) and self-ligating (SL) bracket systems. Gingival crevicular fluid was retrieved before treatment and at 1, 24, and 168 hours after treatment from five maxillary anterior proximal sites on the mesiolabial side of the upper right-to-left canines. An enzyme-linked immunosorbent assay was used to determine RANKL concentrations. The results showed differences in RANKL concentrations between the SL and PEA groups at 1, 24, and 168 hours after bracket insertion. The RANKL concentration at 168 hours in the SL group was higher compared to that in the PEA group, whereas that in the PEA group decreased to the baseline value after 24 hours. RANKL concentration in the passive SL bracket system was higher compared to that in the PEA system due to differences in the force and mechanotherapy of the SL brackets.