Three-dimensional computed tomography comparison of the maxillary palatal vault between patients with rapid palatal expansion and orthodontically treated controls

IntroductionThe aim of this study was to use cone-beam computed tomography to compare changes of skeletal and dental structures of the maxillary palatal vault in a group of growing patients treated for posterior crossbite before and after rapid palatal expansion (RPE) with changes over time in a control group.MethodsThe sample for this retrospective study included 19 patients treated with a hyrax palatal expander at a graduate orthodontic clinic and 19 control subjects who received no RPE. Beginning and progress cone-beam computed tomography scans of all patients were analyzed to measure the anatomic volume, width, height, and anteroposterior dimensions of the palatal region.ResultsProgress scans (after RPE treatment for cases) showed, the mean percentages of change in palatal volume were 10.8% in the controls and 21.7% in the RPE group (P = 0.038); however, there were no statistically significant differences in palatal volume at baseline or at progress scan between the RPE patients and controls. Absolute first molar-to-molar width changes at progress scan were 0.57 mm in the controls and 3.27 mm in the RPE group (P = 0.022). Absolute canine-to-canine width changes at progress scan were 0.45 mm in the controls and 2.79 mm in the RPE group (P = 0.007). There were significant differences in percentage and absolute changes in maxillary width measured from molar to molar and canine to canine between RPE group and controls, but no significant differences in maxillary vault height or anteroposterior dimension changes.ConclusionsAt progress scan, canine-to-canine width, first molar-to-molar width, and anteroposterior length of the palatal maxillary volume in the RPE group approached the measurements of the controls. Palatal volumes (at baseline and progress scan) were not statistically significantly different between the groups.