Rapid palatal expander vs. quad-helix in the orthodontic treatment of cleft lip and palate patients.

Background: The purpose of this study was to compare the results obtained using the rapid palate expander (RPE) and the quad-helix (QH) in the treatment of cleft lip and palate (CLP) patients in mixed dentition.

Methods: In this retrospective clinical trial 28 CLP patients in mixed dentition were enrolled and divided into a group RPE, consisting of 11 patients, and a group QH, consisting of 17 patients. Plaster models before and after treatment were scanned and measurements were made using the software Ortho Analyzer. Measurements, obtained with a digital gauge on plaster models, were regarded as the gold standard and compared with those on digital models. Measurement error was assessed using the Dahlberg formula and the reliability and accuracy of the measurements were evaluated by the interclass coefficient (ICC). The unpaired t-test was used to compare the group RPE with the group QH.

Results: Measurement error found with Dahlberg's method was 0.36. ICC values indicated a strong repeatability of the evaluator's measurements on digital models and an almost perfect repeatability on plaster models, with a value of 0.79 and 0.93, respectively. The ICC for the accuracy of the measurements on digital models was equal to 0.74, indicating a strong agreement with measurements realized on plaster models. Patients in the QH group presented a gain of the anterior palatal diameter significantly greater than those in the RPE group.

Conclusions: The use in mixed dentition of the quad-helix allows obtaining a greater gain of the anterior palatal diameter and a greater symmetry of the dental arch.