Effectiveness of Gold Fixed Retainers Compared to Conventional Stainless Steel Retainers

This randomized clinical trial will compare the effectiveness of a gold-plated multistranded mandibular fixed retainer versus a conventional multistranded stainless-steel fixed retainer in maintaining lower anterior tooth alignment after completion of orthodontic treatment. Eligible participants (post-orthodontic patients requiring mandibular fixed retention) will be allocated in a 1:1 ratio to receive either a gold-plated 0.0195-inch multistranded retainer or an identical-gauge 0.0195-inch stainless-steel multistranded retainer. Participants will be followed for 6 months. The primary outcome is post-treatment stability of mandibular anterior alignment, assessed by changes in Little's Irregularity Index over time, along with retainer failure outcomes (e.g., time to first failure and tooth-level failure events). Secondary outcomes include periodontal health indices and related clinical measures collected at baseline and follow-up visits. For the microbiological assessment, plaque/biofilm will be collected from the retainer using sterile swabs at 1 month, 3 months, and 6 months to evaluate bacterial levels associated with each retainer material.