Clinical results of the maxillary protraction in Korean children.

Sixty subjects with ages ranging from 8 to 13 years were divided into two groups according to the intraoral appliances used. Group I consisted of 47 subjects with rapid palatal expansion (RPE) appliances and group II consisted of 13 subjects with labiolingual appliances (La/Li). Group I was subdivided into three subgroups by age and two subgroups by the timing of the protraction. The cephalometric radiographs of all subjects were analyzed before and after correction of anterior crossbite. The following results were obtained: (1) After maxillary protraction, the maxilla and maxillary dentitions moved forward and downward, and the mandible and mandibular dentitions moved backward and downward. (2) The maxilla moved more forward in the RPE group, compared with La/Li group. (3) The palatal plane angle decreased more in the protraction-during-palatal-expansion group than protraction-after-palatal-expansion group. (4) Age did not show any statistically significant difference.