Long-term maxillary changes in patients with skeletal Class II malocclusion treated with slow and rapid palatal expansion

Introduction: In this study, we evaluated the long-term maxillary changes in skeletal Class II patients who had slow and rapid palatal expansion. Methods: The sample consisted of 70 patients divided in 2 groups: 1 group was treated with cervical headgear with expanded inner bow (CHG) and the other with a Haas-type rapid palatal expansion appliance with cervical headgear (RPE-CHG). Data were collected in the molar and canine regions for basal width, alveolar width, and palatal depth at pretreatment (T1), posttreatment (T2), and postretention (T3). The Student paired t test was used to compare data and independent averages between phases. Results: In both groups, from T1 to T2, there were significant increases in basal width, alveolar width, and palatal depth for the molar region; in the canine region, there was a significant increase only in the alveolar width. From T2 to T3, no significant changes were found for basal and alveolar widths in both groups and regions, but a significant increase was seen in palatal depth in the molar region in the RPE-CHG group. Conclusions: Slow and rapid palatal expansion can expand the maxillae and the maxillary teeth in skeletal Class II patients. Rapid palatal expansion was efficient in the treatment of skeletal Class II patients with severe transverse maxillary discrepancy. Skeletal Class II correction with slow and rapid palatal expansion produced long-term stability (10 years after orthodontic treatment).