An RCT on treatment of palatally displaced canines with RME and/or a transpalatal arch

Abstract

To investigate the effect of rapid maxillary expansion (RME) and/or transpalatal arch (TPA) therapy in combination with deciduous canine extraction on the eruption of palatally displaced canines (PDCs). Hundred and twenty subjects were enrolled in an RCT based on PDCs diagnosed on panoramic radiographs and they were randomly assigned to one of four study groups. Three treatment groups (TGs) (RME followed by TPA therapy plus extraction of deciduous canines, RME/TPA/EC group, 40 subjects; TPA therapy plus extraction of deciduous canines, TPA/EC group, 25 subjects; extraction of deciduous canines, EC group, 25 subjects) were analyzed. A control group (CG, 30 subjects) received no orthodontic treatment. Prevalence rates of eruption of PDCs in the three TGs were compared with the CG at T2. Predictive features at T1 for successful canine eruption were tested in the three TGs. The prevalence of canine eruption was 80 per cent for the RME/TPA/EC group, 79 per cent for the TPA/EC group, 62.5 per cent for the EC group, versus 28 per cent in the CG, with statistically significant differences between all the groups, with the exception of the comparison between RME/TPA/EC and TPA/EC. Predictive pretreatment variables for the success of treatment were less severe sectors of canine displacement, prepubertal stages of skeletal maturity, and an open root apex of PDCs. The use of a TPA in absence of RME can be equally effective than the RME/TPA combination in PDC cases not requiring maxillary expansion, thus reducing the burden of treatment for the patient.