Cone-beam computed tomographic evaluation of the long-term effects of orthodontic retainers on marginal bone levels.

Introduction: Fixed retainers are widely used after orthodontic treatment, sometimes for extended periods, despite insufficient knowledge of their possible long-term adverse effects on the periodontium. The aim of this study was to evaluate whether bonded orthodontic retainers have an adverse long-term effect on the marginal bone levels of the mandibular front teeth.

Methods: The study included 62 consecutive patients in 3 groups: (1) patients who underwent orthodontic treatment and wore a fixed retainer for 10 years, (2) patients who underwent orthodontic treatment but did not have a fixed retainer, and (3) untreated controls.