Maxillary expansion as an interceptive treatment for impacted canines

This was a randomised controlled trial.

Patients in the control group received no treatment, whereas the patient treatment group had a rapid maxillary expander soldered to bands placed on the second deciduous molars or the first permanent molars. Activation of the screw was continued until the palatal cusps of the maxillary posterior teeth were in contact with the buccal cusps of the mandibular posterior teeth. Once the required expansion was achieved, the expansion screw was locked in position. After expansion, all patients were retained with the expander in place for 6 months after which the patients wore a retention plate at night for 1 year.

The main outcome was successful or unsuccessful eruption of the maxillary permanent canines.

The sample comprised 54 patients (32 in the treatment group and 22 in the control). No statistically significant differences were found for any variable at baseline. The prevalence rates of successful eruption of the maxillary canines were 65.7% (21 subjects) in the treatment group and 13.6% (three subjects) in the control. The comparison was statistically significant (chi-square, 12.382; P >0.001).

The use of rapid maxillary expansion (RME) in the early mixed dentition appears to be an effective procedure to increase the rate of eruption of palatally displaced maxillary canines (PDC) compared with an untreated control group.