OPG-RANKL Levels After Continuous Orthodontic Force

Objective: To evaluate the levels of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-β ligand (RANKL) in tension (mesial) and pressure (distal) sides during continuous orthodontic force. Methods: Eighteen canine teeth of 9 adults (5 female, 4 male; age range 17.5-18.9 yrs) with different Angle classifications were included. After first premolar extractions, the maxillary canines were tipped distally by sentalloy closed coil springs with a continuous force of 200 g. Gingival crevicular fluid (GCF) was sampled from mesial and distal gingival crevices of each canine separately at baseline, 1 hour(h), 24 h, 168 h, and 1 month after force application. OPG and RANKL levels were analyzed by ELISA. Results: Concentration of OPG showed an increase in mesial side, while there was a decrease in distal side at 1 h, demonstrating a statistically significant difference (p<0.05). RANKL expression declared no significant changes during the study. Conclusion: Local host response towards continuous orthodontic force might lead changes in OPG expression between mesial and distal sides, revealing an acute cellular response of periodontal status depended upon the type of stress.