Effect of rapid palatal expansion in early tratment and spontaneous correction of maxillary canine-first premolar transposition.

BACKGROUD: The aim of this study was to describe an experimental study carried out in a group of young patients with an early diagnosis of atypical eruption pattern of the maxillary canines and first premolars, identified and treated by rapid palatal expansion (RPE) interceptive therapy. METHODS: This study involved 20 young patients aged between 8 and 12 years (mean age 10+/-0.3 years). Patients were randomly divided into two equal groups (10 patients in each group). The patients in the first group underwent a rapid palatal expansion with an hyrax-type expander. The appliance was activated twice a day for 15 days in order to obtain 7.5 mm of palatal expansion. Then, it was left in situ for six months. The second group was the control group and patients were not treated but only observed. The total number of dental transposition were 30 couple (15 in the first group and 15 in the control group). RESULTS: Among the first group, 13 couple of dental transposition reached the right position in the arch. Two of them remained transposed. Among the control group, 12 of them remained transposed and 3 reached the right position. CONCLUSIONS: Transpositions of the maxillary canines and first premolar is a common tooth malposition in children. Early diagnosis will permit to perform an interceptive treatment that will prevent the full development of transposition.