Risk Factors for the Stability of Secondary Orthodontic Miniscrews Following Initial Insertion Failure.

PURPOSE: To examine the variables that influence the stability of secondary orthodontic anchoring miniscrews after the occurrence of initial placement failure. MATERIALS AND METHODS: A total of 100 miniscrews were reinserted in 71 patients who experienced primary insertion failure. The analysis considered 15 independent variables related to systemic factors and site characteristics. The success rate and risk factors associated with reinsertion were assessed using univariate analyses (chi-square test for categorical variables and Mann-Whitney U test for continuous variables) and a correlation analysis (Spearman correlation analysis to exclude variables that might cause interference in a multivariable model). Significant parameters from the univariate analyses were then integrated into a generalized estimating equation (GEE) model. RESULTS: The success rate of reinsertion was 66.00% (66/100), and the cancellous bone density and the patient's age had a strong correlation with the stability of reinserted miniscrews. CONCLUSIONS: The study indicates that younger patients with miniscrews reinserted in areas with high cancellous bone density are more likely to experience instability. This finding warrants careful consideration by orthodontists when performing miniscrew reinsertion procedures.