Treatment and post-treatment effects of functional therapy on the sagittal pharyngeal dimensions in Class II subjects

Objective To evaluate the craniofacial changes induced by functional appliances with special regard to the oro and nasopharyngeal sagittal airway dimensions in subjects with dentoskeletal Class II malocclusions when compared with an untreated Class II control group immediately after therapy and at long-term observation. Methods A group of 40 patients (21 females and 19 males) with Class II malocclusion treated consecutively either with a Bionator or an Activator followed by fixed appliances was compared with a matched control group of 31 subjects (16 females and 15 males) with untreated Class II malocclusion. The treated sample was evaluated at T1, start of treatment (mean age: 9.9 ± 1.4 years); T2, end of functional treatment and prior to fixed appliances (mean age: 11.9 ± 1.3 years); and T3, long-term observation at the end of growth (mean age: 18.2 ± 2.1 years). Statistical comparisons were performed with independent sample t tests at T1 (baseline characteristics) and for the T1−T2, T2-T3, and T1-T3 changes. Results During active treatment the treated group showed a significant increment in lower airway dimension (PNS-AD1), as well as a significant improvement in the upper airway dimension (PNS-AD2). A significant decrease in the upper adenoid size (AD2-H) was also found. In the longterm evaluation, a significant increase in both lower and upper airway thickness (PNS-AD1; PNS-AD2) and a significant decrease in the upper adenoid thickness were still present in the treated group. Conclusion The treatment with functional appliances produced significant favorable changes during active treatment in the oro- and nasopharyngeal sagittal airway dimensions in dentoskeletal Class II subjects when compared with untreated controls, and these changes were stable in the long-term.