Maxillary Asymmetry with Rapid Palatal Expansion

Signature Grand, Davie, Florida, USA

Background. Numerous orthodontists have observed clinically that during rapid palatal expansion there is asymmetric expansion of the maxilla and the maxillary dentition. Studies have shown that after treatment with RPE, the amount of expansion follows a triangular pattern, with the greatest increase in the maxillary arch width, followed by the nasal width, ending at the frontonasal suture. No studies address the possibility of asymmetry in the expansion. Objective. To investigate whether there is asymmetric expansion of the maxilla after treatment with rapid palatal expander. Methods. The records of twenty-six patients who had been treated with Hyrax rapid palatal expanders were included in this study. Pre- (T1) and post-RPE (T2) posteroanterior cephalograms were traced. On each radiograph, four transverse angular and linear measurements were made per side, drawn away from a midline that extended through Crista galli (Cg) and the midpoint between both Foramen rotundums (Fr). Changes from T1 to T2 on the right side were compared to those on the left side. Also, pre-treatment dental crossbites, airway size, and deviations in the nasal septum were identified to test for correlation with the asymmetric expansion. Results. Significant differences were found between the right and left Lateral nasal wall – Mid Sagittal Reference linear measurements and between the right and left Jugum – Mid Sagittal Reference linear measurements between the pre and post expansion groups (p < .05). Gender was found statistically significant (male/female) (p < .05). No other variable was statistically significant. Conclusion. There is asymmetric expansion of the maxilla after treatment with rapid palatal expander.