Maxillary changes with bone-borne surgically assisted rapid palatal expansion: A prospective study.

INTRODUCTION: The aim of this prospective study was to analyze the postexpansion positional changes of the maxillary halves and their initial stability after transpalatal distraction with a bone-borne distractor and standard corticotomies of the anterior, lateral, and median bony supports of the maxilla without pterygomaxillary disjunction. METHODS: The sample consisted of 21 patients (15 female, 6 male; mean age, 26 years 5 months). Measurements on the maxillary study casts and the posteroanterior cephalograms were obtained before surgery, at the end of palatal expansion, and 10 weeks later. No orthodontic treatment was initiated during the examination period. RESULTS: After palatal expansion, significantly wider measurements were noted in the canine (35.5%), premolar (26.3%), and molar (17.8%) regions. Angulation changes in the premolar (-7 degrees ) and molar (-8 degrees ) segments were observed. No significant changes were seen between the end of palatal expansion and 10 weeks later. Arch perimeter increased by 9.16% between presurgery and 10 weeks after the end of expansion. CONCLUSIONS: The results indicated that more expansion was achieved anteriorly, and that there was buccal tipping of the split maxillary halves. Bone-borne surgically assisted rapid palatal expansion can provide significant expansion of the maxilla with an increase in arch perimeter, and it shows initial stability.