Three-dimensional evaluation of palatal vault changes after unilateral posterior crossbite correction with quad helix or rapid maxillary expansion: A randomized controlled trial with 1-year follow-up.

OBJECTIVES

To compare the effects of quad helix (QH) anchored on permanent molars versus rapid maxillary expansion (RME) anchored on deciduous teeth on palatal morphology in early mixed dentition patients.

TRIAL

DESIGN

A two-arm randomized controlled trial, together with a non-randomized normal bite data for comparison.

METHODS

Seventy-one patients (mean age: QH=9.3years; RME=9.4years) with unilateral posterior crossbite were analysed. The QH group (n=36) and RME group (n=35) were evaluated at baseline (T0), post-retention (T2), and one-year post-treatment (T3). A third age- and sex-matched control group (n=22; mean age=9.1years) served as a normative reference. Evaluated outcomes were 3D palatal measurements, as well as treatment success rate and total treatment duration.

RESULTS

Both treatment groups showed significant increases in palatal surface area, projection plane area, and volume from T0 to T3. The RME group experienced a greater increase in palatal surface area (7.0%) compared to the QH group (4.2%) over the same period (P=0.045). Palatal volume increased notably more in the RME group during active treatment (T0-T2), with an 11.2% gain versus 6.8% in the QH group (P=0.046). By T3, palatal vault dimensions had normalized in both groups compared to the control group. The RME group completed treatment 97days earlier than the QH group.

CONCLUSIONS

Treatment with either QH or RME resulted in normalized palatal vaults compared to the control group. RME had a significantly shorter treatment time but achieved similar success in correcting posterior crossbite as QH. This trial was registered at ClinicalTrials.gov (ID NCT04458506) and Researchweb.org (project number 260581).