Effectiveness of Aligners Versus Rapid Maxillary Expansion

Subjects in this arm will be instructed to wear aligners 24h/day for entire duration of the therapy. They will be asked to remove their retainers only while eating, drinking (except water), or cleaning. At the time of appliance delivery, both written and verbal oral hygiene instructions were given, including methods for cleaning appliances themselves. Also, written informed consent were obtained for each patient or the parents.

The expansion protocol was one quarter-turn twice a day (0.45 mm activation per day) until overcorrection with the maxillary lingual cusps contacting the mandibular buccal cusps. The expander was left passively for retention for a minimum of 6 months. At the time of appliance delivery, both written and verbal oral hygiene instructions were given, including methods for cleaning appliances themselves. Also, written informed consent were obtained for each patient or the parents.