Evaluation of The Stability of Orthodontic Treatment After First Premolar Extraction in Adult Patients Using Bonded Retainer Versus Bonded Retainer Combined With Vacuum Formed Retainer : A Randomized Clinical Trial

Retention is necessary to be done after orthodontic treatment. It aids to prevent the tendency for relapse of teeth toward their pretreatment position. Fixed or removable retention appliances can reduce the risk of relapse, but to date there is still limited evidence on treatment protocols, wearing time and duration. However, long-term retention with bonded lingual retainers is commonly recommended and often considered the gold standard (method of first choice) in orthodontic retention. Regardless of the expected benefits concerning tooth stabilization, aesthetic appearance and independency from the patient's compliance, there have been increasing numbers of reports on undesirable changes in tooth position in the presence of retainers. Since "active" lingual retainers are able to exert forces to teeth, they have been suspected of causing torque changes of adjacent incisors ("X-effect"). Therefore, several authors recommend to insert removable and fixed in both arches for maximum relapse prevention.