Effect of Nanoemulsion Carbonated Hydroxyapatite-Statin Administration on the Alkaline Phosphatase Level during Orthodontic Relapse in Rats

Background: Relapse is acknowledged as a substantial failure after orthodontic correction. As a biomarker of bone formation, alkaline phosphatase (ALP) levels will decline in compressive sites during relapse subsequent to orthodontic tooth displacement. Manipulating alveolar bone remodeling to elevate ALP levels using novel biomaterial is presently regarded as one of the innovative approaches to avert relapse effectively. Purpose: This study aimed to evaluate the effect of carbonated hydroxyapatite (CHA)-statin nanoemulsion on ALP levels in relapsed rats. Materials and Method: In this in vivo study, forty-eight (n= 48) rats were divided into four groups: control, CHA, statin, and CHA-statin, with 12 rats in each group. A 30g mesial traction was applied for seven days using a closed-coil spring extending from the first maxillary molar to the maxillary incisor. Over seven days, CHA, statin hydrogel, and nanoemulsion CHA-statin were injected every three days to preserve the repositioned teeth. Removing the appliances allowed for relapse to occur. ALP levels were assessed using an enzyme-linked immunosorbent assay on days 0, 1, 7, and 14 after debonding. The acquired data was analyzed using analysis of variance and a post hoc Tukey's test with a significance level of p< 0.05. Results: The average ALP levels between the groups did not differ significantly (p> 0.05) on days 0 and 1 of relapse. The mean values were highest in the CHA-statin nanoemulsion group. The control group exhibited the lowest average ALP levels on day 7 of the relapse phase, followed by Group CHA, Group statin (St), and Group CHA-St, with a significant difference (p< 0.05). On day 14, the CHA-St group had the highest average ALP levels (p< 0.05), while the CHA and St groups did not differ (p> 0.05). Conclusion: The results indicated that nanoemulsion CHA-statin could elevate ALP levels during orthodontic relapse. © 2025 Elsevier B.V., All rights reserved.