Effect of RME and headgear treatment on the eruption of palatally displaced canines: a randomized clinical study.

Objective: To determine the effectiveness of orthodontic treatment finalized on the maintenance/ improvement the upper arch perimeter to assist in the successful eruption of palatally displaced maxillary canines (PDCs). Materials and Methods: The randomized prospective design comprised 64 subjects with PDCs who were randomly assigned to one of three groups: cervical pull headgear (HG); rapid maxillary expansion and cervical pull headgear (RME/HG); or untreated control group (CG). Panoramic radiographs and lateral cephalograms were evaluated at the time of initial observation (T1) and after an average period of 18 months (T2). At T2 the success of canine eruption was evaluated. A superimposition study on lateral cephalograms was undertaken to evaluate the T1–T2 changes in the sagittal position of the upper molars in the three groups. Results: The prevalence of successful eruption was 85.7% in the RME/HG group and 82.3% in the HG group. Both these prevalence rates were significantly greater than the success rate in untreated control subjects (36%). The cephalometric superimposition study showed a significant mesial movement of the upper first molars in the CG compared with the HG and RME/HG groups. Conclusions: The use of rapid maxillary expansion and headgear (or headgear alone) in PDC cases increases the success rate of eruption of the canine significantly (almost three times more than in untreated controls). (Angle Orthod. 2011;81:370–374.