Mandibular response after rapid maxillary expansion in mixed dentition children with different vertical growing patterns: A retrospective study

Introduction: This study aimed to evaluate the mandibular development induced by rapid maxillary expansion (RME) therapy in mixed dentition patients with different vertical growth patterns. Methods This retrospective design incorporated two cohorts: a control group consisting of pediatric subjects presenting individualized malocclusion, and an experimental group subjected to RME therapy. A total of 60 subjects were included in this retrospective study, 37 in the RME group (17 males and 20 females) and 23 in the control group (13 males and 10 females). Subsequent to quantifying 22 pertinent morphometric parameters via Dolphin Imaging software, the participants were classified into either high-angle or even-angle subgroups based on MP-FH value. Changes in the groups during the observation period were calculated, compared, and statistically analyzed with a t-test. Results Compared to the control group, both ANB angle and overjet tended to decrease after treatment in the RME group ( P   0.05). Within the even-angle experimental subgroup, the ANB angle, Wits appraisal, and overjet markedly decreased when contrasted with their even-angle control counterparts (P < 0.05). Notably, a substantive decrease in overjet was solely observable in the sagittal dimension among the high-angle expansion subgroup when compared to the high-angle control subgroup (P  0.05). Conclusions The results of current investigation substantiate that RME therapy promoted sagittal growth of the mandible in subjects with even-angle vertical growth patterns through long-term observation. Whereas no analogous tendency was discerned in subjects manifesting high-angle vertical growth patterns. In addition, the mandibular plane angle did not increase after RME in children with high angles, thereby negating the hypothesis that high angles serve as a contraindication for RME.