Mandibular Behavior after Rapid Maxillary Expansion: A Clinical Study

Background: Rapid Maxillary Expansion (RME) is a primary part of the contemporary orthodontic treatment plans. In addition to the maxilla, it is important to know its effect on the other dentofacial components. Some studies showed dentofacial changes after RME in the sagittal and vertical planes. The clinical importance of these changes is controversial. Objective: To investigate the mandibular changes after RME as the only treatment intervention in the sagittal and vertical planes. Methods: Twenty-eight growing patients aged 4-14 years were included in the current study. The bonded acrylic splint expander was used. Lateral cephalometric radiographs were taken at the beginning of the treatment (T1) and after a retention phase of six months (T2). The mandibular changes were assessed using vertical parameters (SN.MP, MMA, LAFH/TAFH, S.AR/AR.GO) and sagittal parameters (SNB, S.N.POG, N.A.POG). The changes between T1 and T2 were examined by paired samples T-test. Results: Two parameters showed a backward rotation in the vertical plane. The parameter S.AR/AR.GO showed a significant increase. The skeletal convexity increased with no clinical significance. Conclusion: There were statistically significant changes in the sagittal and vertical planes with no clinical importance. RME may affect the mandibular condyle position.