Effect of Local Subperiosteal Zoledronic Acid Injection on the Survival of Orthodontic Miniscrews

Background: Orthodontic miniscrews are widely used as temporary anchorage devices; however, failure remains a clinical concern. Bisphosphonates may enhance bone stability, but evidence on their local application is limited. Objective: To evaluate the effect of local subperiosteal zoledronic acid (ZA) injection on miniscrew survival and peri-miniscrew inflammation. Materials and Methods: This triple-blind, split-mouth randomized controlled trial included 68 patients requiring bilateral maxillary premolar extraction. Miniscrews were placed bilaterally, with one side randomly receiving a 0.5 mL solution of zoledronic acid at 1 mg/mL concentration and the contralateral side saline. Injections were administered weekly for three weeks. Orthodontic force (\~250 g) was applied 24 hours after final injection. The primary outcome was miniscrew survival at 6 months. Paired comparisons were analyzed using McNemar test, with odds ratios (ORs) and 95% confidence intervals (CIs).