Mandibular 3D position changes in miniscrew-assisted rapid palatal expansion(MARPE): a retrospective clinical trial using CBCT

Abstract Background: The aim of this study was to evaluate the immediate and short-term effects of miniscrew-assisted rapid palatal expansion (MARPE) on mandibular 3D position in treatment of skeletal Class I malocclusion with maxillary transverse deficiency in adults.Methods: A retrospective study was conducted using cone-beam computed tomography (CBCT) scans of 20 adults with skeletal Class I malocclusion and maxillary transverse deficiency who underwent MARPE. Three CBCT scans were obtained before treatment (T0), immediately after expansion (T1) and after a six-month consolidation period (T2). Mandibular landmarks were measured with respect to axial, sagittal, and coronal reference planes respectively. Repeated measures ANOVA and LSD multiple comparison were used for statistical analysis.Results: The mandibular rotated clockwise at T1 and relapsed to its initial position at T2. The lateral displacement was unremarkable.Conclusions: When MARPE was used to treat skeletal Class I malocclusion with maxillary transverse deficiency, it caused a transient clockwise rotation of the mandible. However, the mandible did not show sagittal, vertical and horizontal position changes in short-term evaluation.