Osteoprotegerin level differences in orthodontic treatment with self-ligating and conventional preadjusted brackets at early aligning and leveling phase

Aim: This study aims to investigate the differences in osteoprotegerin (OPG) concentrations in early aligning and leveling of orthodontic treatments using self-ligating and conventional preadjusted brackets. Materials and methods: Three groups consisting of two experimental groups and one control group participated in this study. A total of 18 patients were selected according to the following inclusion criteria: Little’s irregularity index on maxillary anterior teeth ranging from 4 to 9 mm, nonextraction orthodontic treatment on the experimental group, and no previous orthodontic treatment. The experimental group received orthodontic treatment with either a passive self-ligating or conventional preadjusted bracket system, while the control group did not receive orthodontic treatment. Gingival crevicular fluid (GCF) collection was done at baseline, 1, 24, and 168 hours on five points of maxillary anterior proximal sites, from the mesiolabial side of the canine to the mesiolabial side of its contralateral side. The OPG concentration was assessed by enzyme-linked immunoabsorbent assay (ELISA). Results: The OPG concentration on both bracket systems was decreased in a time-dependent manner. Decreasing concentration was maintained up until 168 hours on the self-ligating bracket, while conventional preadjusted bracket showed significantly increasing concentration at 168 hours (p = 0.004). Levels of OPG were significantly lower on self-ligating bracket compared with the conventional bracket at 1, 24, and 168 hours (p < 0.005). Conclusion: Both bracket systems showed decreasing OPG concentration up to 24 hours after orthodontic activation. A maintained decreasing level of OPG was observed on the self-ligating bracket group at 168 hours, and it showed significant lower OPG concentration compared with the conventional preadjusted bracket group at 1, 24, and 168 hours after initial force application. Clinical significance: The maintained decreasing level of OPG could indicate bone resorption that allows tooth movement into correct alignment that still occurs on self-ligating bracket up to 168 hours after initial activation.