Effectiveness of Treatment Modalities for the Correction of Anterior Crossbite in Children: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Anterior crossbite in children is a common malocclusion that, if left untreated, may lead to occlusal dysfunction, impaired craniofacial growth, and long-term periodontal or temporomandibular complications; however, a comprehensive synthesis of high-quality evidence comparing the effectiveness of different early treatment modalities across skeletal, functional, and dental etiologies remains limited. This study was designed as a systematic review and meta-analysis to investigate and compare the efficacy of different orthodontic approaches for treating anterior crossbites in children during their growth phase. A thorough search of the literature was performed up to September 2025 across several databases, including PubMed, Cochrane Library, Scopus, Web of Science, and Google Scholar, without applying any restrictions on language or publication year. Only randomized controlled clinical trials (RCTs) focusing on children aged 6-12 years who received orthodontic treatment for anterior crossbite correction were considered eligible. Two reviewers independently handled the processes of study selection, data collection, and risk-of-bias evaluation using the RoB-2 tool, with any disagreements resolved through consultation with a third reviewer. Data synthesis was carried out using RevMan 5.4, and the strength of the evidence was assessed according to the GRADE guidelines. A total of 21 RCTs involving 854 participants were included, comprising 18 studies on skeletal, two on functional, and one on dental anterior crossbite. Intraoral non-skeletally anchored appliances demonstrated modest improvements in sagittal skeletal relationships (ANB mean difference (MD) = 0.29°-3.12°) and clinically meaningful overjet correction (MD = 1.4-5.9 mm), primarily through dentoalveolar mechanisms rather than true skeletal modification. In contrast, facemask therapy combined with rapid maxillary expansion (FM-RME) produced the most pronounced skeletal effects, with pooled estimates showing significant increases in ANB (MD = 3.54°) and SNA (MD = 1.37°), along with a reduction in SNB (MD = -2.14°), although substantial heterogeneity was observed across studies. Skeletally anchored facemask therapy did not demonstrate a clinically meaningful advantage in overall sagittal correction compared with conventional tooth-borne facemask therapy (ANB MD = 0.07°), although a small additional improvement in maxillary advancement was noted (SNA MD = 0.59°). Considerable variability existed across trials in terms of appliance design, treatment protocols, follow-up duration, and outcome assessment methods. The overall certainty of evidence ranged from very low to moderate. In conclusion, early orthodontic treatment of anterior crossbite in growing children is effective, with outcomes largely influenced by the underlying etiology and the type of appliance used. Intraoral appliances are appropriate for dental and functional crossbites and mild skeletal discrepancies, whereas FM-RME remains the most reliable modality for achieving significant skeletal correction in true skeletal anterior crossbite cases. The additional benefit of skeletal anchorage appears to be limited compared with conventional approaches. Further high-quality, standardized RCTs with consistent outcome measures and long-term follow-up are needed to increase the evidence base strength, because of the heterogeneity of included studies and the typically low confidence of the evidence.