Evaluating Receptor Activator of Nuclear Factor Kappa B Ligand (RANKL) and Osteoprotegerin (OPG) expression during canine retraction: A comparison between periodontal distraction versus conventional retraction.

OBJECTIVE: To evaluate and compare the expression levels of Receptor Activator of Nuclear Factor Kappa B Ligand (RANKL) and Osteoprotegerin (OPG) in canine periodontal tissues subjected to periodontal distraction versus conventional retraction at different treatment time points. MATERIALS AND METHODS: The study involved 40 cuspids from 20 patients (9 males, 11 females) randomly allocated to either the periodontal distraction (PD) group or the conventional retraction group. Appliances were applied by a single practitioner in a split-mouth design. In Group 1 (PD), a trans-palatal arch and Hyrax expanders were used following premolar extraction with osteotomies performed to facilitate distraction. Group 2 (conventional retraction) used MBT brackets with sectional archwires and elastic chains. Gingival crevicular fluid samples were collected on the first day (D0), after 1 week (W1), and 6 weeks (W6) and OPG and RANKL levels were analyzed using ELISA test. RESULTS: There was a significant difference in canine retraction duration between methods (P < 0.001), with periodontal distraction taking 24.1 ± 2.08 days versus 110.5 ± 4.84 days for conventional retraction. RANKL levels showed no baseline difference, but were significantly higher in the periodontal distraction group at weeks 1 and 6 (P = 0.010 and P = 0.001, respectively). OPG levels were initially similar, but by weeks 1 and 6, they were significantly lower in the periodontal distraction group (P = 0.001). CONCLUSION: The periodontal distraction method significantly reduces the duration of canine retraction and enhances osteoclastic activity, as evidenced by increased RANKL and decreased OPG levels, facilitating accelerated tooth movement through efficient bone resorption and remodeling.