Comparison between Flexible Spiral and Ribbon Flat Wires Used in Fixed Lingual Retainers: A Randomized Clinical Trial

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, ۱۸۸ 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 ۱۸-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<۰.۰۵.Results: Data from ۱۷۸ patients (۹۴ ribbon flat; ۸۴ flexible spiral) were analyzed. The overall failure rates were ۱۰.۶۴% for ribbon flat and ۷.۱۴% for flexible spiral retainers (p=۰.۴۱۶). Type III failures were the most frequent in both groups. The mean time to failure was ۲۷۰±۱۴۲.۳ days for ribbon flat and ۲۱۰±۱۵۵.۰ days for flexible spiral wires (p=۰.۷۰۴). 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 ۱۸ months. Either retainer type may be effectively used for long-term post-orthodontic stability.

کلیدواژه ها:

Fixed Lingual Retainer ، Orthodontic Treatment ، Ribbon Flat Wire ، Flexible Spiral Wire