Effectiveness of Myofunctional Appliances in Orthodontics: A Systematic Review

Objective: To systematically evaluate the evidence regarding the effectiveness of myofunctional appliances in the treatment of skeletal and dento-alveolar malocclusions, particularly class II malocclusions, and their integration with orofacial myofunctional therapy (OMT). Methods: A systematic search was conducted using the PubMed, Scopus, Embase, and Cochrane Library databases for articles published from 1990 to 2024. Embase and Cochrane Library databases for articles published from 1990 to 2024. Inclusion criteria were randomized controlled trials (RCTs), clinical trials, and longitudinal studies evaluating the impact of myofunctional devices on skeletal and dental structures. Inclusion criteria were RCTs, clinical trials, and longitudinal studies assessing the impact of myofunctional appliances on skeletal and dental structures. The PRISMA 2020 checklist was followed. Risk of bias was assessed using the Cochrane RoB-2 and ROBINS-I tools. Results: A total of 2634 studies were selected, 41 met the eligibility criteria. Out of 2634 studies screened, 41 met the eligibility criteria. The majority of studies focused on the Twin Block, Bionator, Frankel, Herbst, and Jasper Jumper appliances. Significant changes were observed at dento-alveolar levels, particularly in the reduction of overbite and Class II relationships of molars. Skeletal improvements (increase in SNB, reduction in ANB) were more modest and depended on growth stages. Studies combining OMT with device therapy have shown improved long-term stability and functional improvements. Conclusions: Myofunctional appliances are effective in correcting Class II malocclusions, primarily through dento-alveolar changes, with slight skeletal effects. The combination of OMT improves muscle tone, reduces relapses, and improves compliance. However, heterogeneity in study design and the lack of long-term RCTs warrant further research.