Influence of rapid palatal expansion on maxillary incisor alignment stability.
BACKGROUND
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).


METHODS
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.


RESULTS
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.


CONCLUSIONS
RME did not influence long-term maxillary anterior alignment stability.
Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil. luizfiliphecanuto@yahoo.com.br
Luiz Filiphe Gonçalves
LF
Canuto
Marcos Roberto
MR
de Freitas
Guilherme
G
Janson
Karina Maria Salvatore
KM
de Freitas
Patrícia Paschoal
PP
Martins
D000293:Adolescent; D002648:Child; D003724:Dental Arch / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D007180:Incisor; D008297:Male; D008311:Malocclusion, Angle Class I / Q000628:therapy*; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008437:Maxilla; D018704:Orthodontic Retainers; D010155:Palatal Expansion Technique / Q000009:adverse effects* / Q000295:instrumentation; D021362:Palate, Hard / Q000033:anatomy & histology; D012008:Recurrence; D013997:Time Factors; D016896:Treatment Outcome