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 tothe oro and nasopharyngeal sagittal airway dimensions in subjects with dentoskeletal Class II maloc-clusions 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 consec-utively either with a Bionator or an Activator followed byfixed appliances was compared with a matchedcontrol group of 31 subjects (16 females and 15 males) with untreated Class II malocclusion. The treatedsample was evaluated at T1, start of treatment (mean age: 9.9±1.4 years); T2, end of functional treat-ment and prior tofixed appliances (mean age: 11.9±1.3 years); and T3, long-term observation at the endof growth (mean age: 18.2±2.1 years). Statistical comparisons were performed with independentsample t tests at T1 (baseline characteristics) and for the T1T2, T2-T3, and T1-T3 changes.Results:During active treatment the treated group showed a significant increment in lower airwaydimension (PNS-AD1), as well as a significant improvement in the upper airway dimension (PNS-AD2). Asignificant decrease in the upper adenoid size (AD2-H) was also found. In the longterm evaluation, asignificant increase in both lower and upper airway thickness (PNS-AD1; PNS-AD2) and a significantdecrease in the upper adenoid thickness were still present in the treated group.Conclusion:The treatment with functional appliances produced significant favorable changes duringactive treatment in the oro- and nasopharyngeal sagittal airway dimensions in dentoskeletal Class IIsubjects when compared with untreated controls, and these changes were stable in the long-term.