Effects of rapid maxillary expansion on hearing

Aim: This systematic review aimed to evaluate the effects of Rapid Maxillary Expansion (RME) on hearing improvement in children and adolescents with conductive hearing loss. Methods: A comprehensive search was conducted across eleven databases and grey literature. Studies included randomized controlled trials, cohort studies, and observational studies involving patients with maxillary atresia and conductive hearing loss due to otitis media. The primary outcome was hearing improvement measured in decibels (dB), assessed at pre-intervention, immediately post-intervention, and follow-up intervals of 3 to 24 months. The risk of bias was assessed using RoB 2.0 and ROBINS-I tools, while the GRADE system was used to evaluate the certainty of the evidence. A random-effects metaanalysis was performed, and heterogeneity was quantified using I² statistics. Results: Twelve studies, including 337 participants, were included. The meta-analysis demonstrated a significant improvement in hearing thresholds following RME, with a pooled mean difference of -6.56 dB (95% CI: -10.32 to -2.81). The RME vs. control group comparison showed a mean difference of -5.25 dB (95% CI: -9.89 to -0.62). However, high heterogeneity (I² = 88%) was noted. Some studies reported a relapse in auditory improvements after the retention period. The GRADE assessment indicated moderate certainty of evidence due to methodological limitations. Conclusion: RME improves hearing in patients with conductive hearing loss, but high-quality studies are needed to confirm long-term benefits and assess specific populations. Future research should address the variability in treatment protocols and follow-up durations.