Comparative Effectiveness Fixed Functional Appliances VS Clear Aligners In Class II Malocclusion Correction: A Systematic Review Of Skeletal, Dental And Patient-Centered Outcomes

Abstract

Background

Class II malocclusion is a common orthodontic condition that has been conventionally treated by fixed functional appliances (FFAs). Aesthetic and removable alternative, the clear aligners (CAs) have been adopted recently. Nevertheless, their relative clinical effectiveness in producing skeletal and dental correction is a subject of controversy.

Objectives

This systematic review and meta-analysis are designed to assess and compare the effectiveness of fixed functional appliances and clear aligners as a method of correcting Class II malocclusion in terms of skeletal, dental, and soft tissue outcomes, duration of treatment and patient-centered outcomes.

Methodology

A systematic literature search was done in PubMed, Scopus, Web of Science, and Cochrane Library databases from January 2015 to April 2025. Only the original clinical studies RCTs, prospective and retrospective cohort studies, which compare FFAs and CAs in Class II malocclusion correction were included. Data were extracted according to PRISMA guidelines and analyzed using Review Manager (RevMan) software. The main outcomes were ANB changes, reduction of overjet and duration of the treatment. Secondary outcomes were incisor inclination, soft tissue profile, root resorption and patient-reported outcomes.

Results

There were 8 studies involving 648 patients that met the inclusion criteria. The meta-analysis showed that ANB angle by FFAs was attenuated moderately (mean difference: –1.74°/year, 95% CI: -2.50 to -0.98) suggesting skeletal improvement. CAs showed treatment durations that were shorter (mean difference: –6.31 months; 95% CI: -8.37 to -4.24; P < 0.001) . Both modalities were successful in reducing overjet and improving dental alignment, CA’s provided better control of incisor inclination and better patient comfort.

Conclusion

Both FFAs and CAs are effective in correction of Class II malocclusion. FFAs produce more significant skeletal changes especially during pubertal growth which is beneficial, CAs, however have aesthetic, comfort and shorten treatment duration advantage. Selection of a treatment modality should be patient specific and growth potential and compliance should be considered.