Pharyngeal airway changes in pre-pubertal children with Class II malocclusion after Frankel-2 treatment

Aim To evaluate two-dimensional changes in pharyngeal airway dimensions in pre-pubertal children with a Class II malocclusion treated with a Frankel-2 appliance compared to a matched non-treated control sample. Materials and Methods Lateral cephalograms obtained from 28 consecutively treated pre-pubertal children before (TO) and after (T1) a one-year Frankel-2 treatment were analysed. Frankel-2 appliance was used for at least 18 hr/day during 12 months. The control group was matched as closely as possible. All the cases presented normal facial growth pattern. Sagittal and vertical cephalometric measurements assessing maxillary and mandibular skeletal positions, as well as sagittal pharyngeal airway dimensions, were calculated. Intraclass correlation coefficient was calculated in order to determine reliability. Differences based on age for all the outcome variables at TO were compared with an independent t-test. A MANOVA was used thereafter to determine if any factors and their interactions were associated with changes in the outcome variables. Differences between T1 and TO were evaluated with either a t-student test or a Mann Whitney U test. Results At TO differences between groups were noted for several variables. These differences were considered during the follow-up statistical analysis. Changes between groups after treatment (T1-TO) were noted for SNB, PNS to Ba, McNamara Low and Middle to S (increase in treatment group), and ANB and AD1 to Ba (decrease in treatment group). Conclusions Some pharyngeal two-dimensional airway dimensions changed in Class II malocclusion pre-pubertal patients during a one-year treatment with Frankel-2 appliances.