فهرست نشریات علمی دسترسی آزاد ایران

Aim: Relapse of mandibular anterior crowding remains a common post-orthodontic challenge regardless of treatment technique. Fixed lingual retainers, which minimize the need for patient compliance, are considered effective in maintaining alignment. Various wire types, including flexible spiral and ribbon flat wires, have been introduced, but comparative evidence on their clinical performance is limited. This study aimed to evaluate and compare the failure rates and types between ribbon flat and flexible spiral fixed retainers.Methods: In this randomized, double-blind clinical trial, 188 orthodontically treated patients were allocated into two groups: ribbon flat wire and flexible spiral wire retainers. After bonding, patients were examined every three months over an 18-month follow-up period. Failures were classified as: Type I (wire fracture), Type II (detachment at wire–composite interface), and Type III (adhesive failure on enamel). Data were analyzed using Chi-square and Mann–Whitney U tests with a significance level of p<0.05.Results: Data from 178 patients (94 ribbon flat; 84 flexible spiral) were analyzed. The overall failure rates were 10.64% for ribbon flat and 7.14% for flexible spiral retainers (p=0.416). Type III failures were the most frequent in both groups. The mean time to failure was 270±142.3 days for ribbon flat and 210±155.0 days for flexible spiral wires (p=0.704). The type of orthodontic treatment (with or without extraction) did not significantly affect outcomes.Conclusion: Both ribbon flat and flexible spiral fixed retainers exhibited comparable clinical performance and failure characteristics over 18 months. Either retainer type may be effectively used for long-term post-orthodontic stability.