Changes in respiratory and cardiac functions of patients with mandibular deficiency after treatment with a removable functional appliance

BACKGROUND an‎d AIM: There is no study on respiratory or cardiac function of patients with mandibular deficiency before or after treatment. This preliminary trial was conducted for the first time to assess respiratory/cardiac parameters of such patients before and after treatment (compared to healthy controls) with a removable functional appliance. METHODS: This before-after clinical trial was performed on 20 patients with class II division 1 malocclusion (mandibular deficiency with normal maxilla) and 20 matched control subjects at the peak of the mandibular growth spurt. Bionator removable functional appliance was used for 9 months to treat class II cases. Capnography and pulse oximetry were used to record respiratory parameters [end-tidal carbon dioxide pressure (PETCO2), respiration rate (RR), oxygen saturation (SPO2), and pulse rate (PR)]. Groups were compared using paired and unpaired t-tests (α = 0.05). RESULTS: Carbon dioxide (CO2) and oxygen (O2) did not change significantly after treatment (P > 0.50, paired t-test). However, RR and PR reduced significantly after the treatment (P < 0.001, paired t-test). CO2 in healthy subjects was not different from pre-treatment or post-treatment values in class II patients (P > 0.10). O2 in healthy subjects was not different from pre-treatment or post-treatment values in class II patients (P > 0.20, independent samples t-test). The RR in healthy controls differed from pre-treatment (P < 0.001) but not post-treatment values in class II patients (P = 0.541). The PR in the healthy controls differed marginally significantly from pre-treatment (P = 0.067) but not post-treatment values (P = 0.752). CONCLUSION: In patients with mandibular deficiency, treatment with a Bionator functional appliance improves RR and PR back to normal levels. O2 and CO2 levels were not affected in class II patients.