Comparison Between CAD/CAM and Conventional Mandibular Fixed Retainers.

The devices compared in this study are 'retainers', i.e. fixed orthodontic retainers applied to the lingual surface of the central and lateral incisors and lower canines bilaterally. Their function is to maintain dental alignment once fixed orthodontic therapy has ended. In particular, the CAD/CAM device Keeppy patented by the company Leone SpA (Via Ponte a Quaracchi 50, Sesto Fiorentino, Florence) will be compared with the standard retainer made from a steel braided wire (Ortho FlexTech, Reliance Orthodontic Products Inc., 1540 West Thorndale Ave, Itasca, Illinois, USA). This is a single-center, national, controlled, superiority, randomized, crossover, open-label study. The aim of this study is to evaluate whether the CAD/CAM retainer results in fewer failures (fractures or detachments) over a period of 6 months and 2 years compared to the standard retainer. In addition, the aim of the study is to evaluate whether the Keeppy device results in the maintenance of better periodontal health as judged by the use of plaque and bleeding indices on the surfaces of the lower six anterior teeth compared to the standard retainer. Other objectives consist of the patient's assessment of pain, difficulty in speaking and esthetic satisfaction and the stability of the lower anterior tooth sector.

Inclusion Criteria: * Patients who have completed fixed orthodontic therapy between the ages of 13 and 20 years; * Patients whose parents will sign the informed consent Exclusion Criteria: * Presence of dental anomalies in number (excess or deficiency) in the lower anterior teeth * Patients with metal allergies.