Influence of rapid palatal expansion on maxillary incisor alignment stability.Am J Orthod Dentofacial Orthop 2010; 137(2):164.e1-6; discussion 164-5AJ
The purpose of this retrospective study was to compare the long-term stability of maxillary incisor alignment in patients treated with and without rapid maxillary expansion (RME).
The sample comprised 48 subjects with Class I and Class II malocclusions, treated without extractions with fixed edgewise appliances, divided into 2 groups according to the treatment protocol: group 1 comprised 25 patients (15 girls, 10 boys) at a mean initial age of 13.53 years (SD, 1.63), who had RME during orthodontic treatment. Group 2 comprised 23 patients (13 girls, 10 boys) at a mean initial age of 13.36 years (SD, 1.81 years), treated with fixed appliances without RME. Maxillary dental cast measurements were obtained at the pretreatment, posttreatment, and long-term posttreatment stages. Variables assessed were the irregularity index and maxillary arch dimensions. Intergroup comparisons were made with independent t tests.
Greater transverse increases were found during treatment in the group treated with RME. However, during the long-term posttreatment period, no significant difference was observed in the amount of incisor crowding relapse between the groups.
RME did not influence long-term maxillary anterior alignment stability.