Comparing posterior airway space changes in Class III patients treated with face mask and reverse chin cup

Objectives: The aim was to compare the posterior airway changes in patients treated with a face mask and reverse chin cup and to assess the stability over a 1.5-year follow-up period. Material and Methods: This historical cohort study consisted of two groups containing 20 patients with skeletal Class III malocclusion. The average age of the patients in groups one (Facemask) and two (reverse chin cup) was 7.77 ± 1.30 years and 8.6 ± 1.36 years, respectively. Seventeen cephalometric variables were measured before, after treatment, and after a 1.5-year follow-up. Comparisons were made within each group and between the two groups. Repeated measures, analysis of variance, or Friedman test were used. Results: There was no significant difference between the two groups in the posterior airway space. For patients who used face masks, six variables (AD1-posterior nasal spine [PNS], AD2-PNS, anterior nasal spine [ANS]-PNS, ANS-PNS-PPW, AA-PNS, and PNS-P) considerably increased ( P < 0.05). In the reverse chin cup group, three variables (AD2-PNS, ANS-PNS-PPW, and PNS-P) considerably changed ( P < 0.05). Moreover, no significant changes ( P > 0.05) were observed in any variables after the 1.5-year follow-up period. Conclusion: In this study, the reverse chin cup and face mask effectively corrected Class III malocclusion and significantly increased the posterior airway space. The face mask showed greater enhancement compared to the reverse chin cup, and these improvements were maintained after a 1.5-year follow-up. However, the two groups had no significant difference regarding the posterior airway space changes.