[A cone-beam computed tomography evaluation of maxillary protraction with repetitive rapid palatal expansions and constrictions]

Abstract

Objective: To investigate the effects of maxillary protraction combined with repetitive rapid palatal expansions and constrictions (RPE/C) vs. rapid palatal expansion (RPE) alone using cone-beam computed tomography (CBCT).

Methods: Twenty four subjects with maxillary retrusion were recruited and block randomized into either the control group (n = 12) or the RPE/C (n = 12) group.

Control group: facemask protraction after RPE. RPE/C group: facemask protraction after RPE/C. 3D reconstruction, landmarks identifying, superimposition and cephalometric analysis were performed to compare the pre-treatment and post- treatment CBCT images.

Results: One subject in the RPE/C group was lost to follow up during the treatment. Maxilla moved forward [(2.5±1.0) mm] after maxillary protraction with RPE/C, which was significantly greater than that in the control group [(1.6±0.8) mm] (P < 0.05). The distance of basion to subspinale (Ba-A) increased [(3.1±1.0) mm] in the RPE/C group, which was significantly greater than that in the control group [(2.2 ± 0.9) mm] (P < 0.05). The amount of forward movement of upper first molars was significantly greater in the RPE/C group (P < 0.05).

Conclusions: Maxillary protraction with RPE/C might positively affect the forward movement of maxilla compared with the RPE alone protocol with the early treatment of maxillary retrusion patients.