Acta Odontologica Turcica (Sep 2019)
Effects of combined rapid palatal expansion and face mask therapy on mandibular dentition
Abstract
Objective: The study aimed to evaluate the effects of combined rapid maxillary expansion (RPE) and face mask (FM) application on the mandibular dentition. Materials and Method: In this retrospective study pre- and post-treatment cephalometric radiographs and orthodontic models of 25 patients (10 female, 15 male) with a mean skeletal age of 12 years and 1 month, being in permanent dentition, having skeletal Class 3 anomaly (ANB<0) accompanying with maxillary retrognathism and posterior crossbite who had been treated with a combined application of bonded Hyrax RPE and FM were evaluated. The mean duration for the RPE-FM application was 8.7 months. The lower arch intermolar and intercanine widths, arch depth and the amount of crowding between canines were evaluated using Littles’ Irregularity Index (LII) on the 3D images of the models utilizing the 3Shape OrthoAnalyzer 2013-1 program. Mandibular incisors’ inclination (IMPA degree) were determined on cephalometric radiographs. The statistical evaluation was done with paired t-test, and the statistical significance was set at p<0.01. Results: In the lower dental arch, a significant increase of 1.38 mm was found in the intermolar width (p<0.001). While no significant difference was observed in the intercanine width, there was a significant decrease in the arch depth (1.45 mm; p<0.001) and a significant increase in the LII value (1.46 mm; p<0.01). Besides, there was no significant difference in the IMPA degree. Conclusion: Combined RPE-FM application in the treatment of skeletal Class 3 malocclusion provides an increase in mandibular intermolar width that may increase the arch length. On the contrary, a decrease in the arch depth results in shortening of the arch length. Clinicians should be conscious of a mandibular anterior crowding during this type of combined therapy.
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