Objective To evaluate the long-term stability of maxillary protraction in the treatment of Angle Class Ⅲ malocclusion in children with mixed dentition. Methods A comprehensive search of Cochrane Library, PubMed, Ovid, ScienceDirect, Wiley, China Academic Journal Full-text Database, China Biology Medicine Disc, China National Knowledge Infrastructure, China Science and Technology Journal Database, Wan Fang database and other foreign and Chinese databases was conducted until 18 August 2021. Literature screening, quality evaluation and data extraction were carried out by two scholars. Meta-analysis was carried out by RevMan5.3 software, and the evidence quality of the outcome index was evaluated using the Grading of Recommendations Assessment, Development and Evaluation evidence grading system. The results consist of active treatment changes and posttreatment changes, as well as the overall changes in SNA, SNB, ANB, Co-A, Co-Gn, SN-GoGn. Results Ten articles that met the requirements were included. The treated group, which comprised patients with Angle Class Ⅲ malocclusion treated by maxillary protraction, was compared with the untreated Class Ⅲ control group. The results of the meta-analysis showed statistical differences in the increase in SNA, SNB, ANB, Co-A and Co-Gn during the T1-T2 period (P<0.05) and no statistical difference in SN-GoGn (P>0.05). During the T2-T3 period, SNA, SNB, ANB and Co-Gn significantly decreased (P<0.05), but Co-A and SN-GoGn had no significant change (P>0.05). During T1-T3, SNA, SNB, ANB, Co-A and Co-Gn was significantly changed (P<0.05), whereas SN-GoGn had no significant change (P>0.05). Conclusion The analysis of patients with Angle Class Ⅲ malocclusion who were treated by maxillary protraction revealed that the maxillary and mandibular effects come from the active treatment period. Although the Class Ⅲ growth pattern had a tendency to be re-established during the posttreatment period, facemask therapy remarkably improved the maxillary and mandibular sagittal positions and maxilla-mandible relationship, promoted midface growth and inhibited mandibular growth during the long-term observation. More large samples and high-quality clinical studies are needed to verify this conclusion.
