First premolar extraction effects on upper airway dimension in bimaxillary proclination patients

Objective: To determine how orthodontic treatment with first premolar teeth extracted and the associated arch dimensional changes in bimaxillary proclination patients affect the upper airway dimensions. Materials and Methods: Pre- and postorthodontic treatment cephalograms and dental casts of 40 bimaxillary proclination patients (ages ranged between 18 and 23 years) were used for this study. Patients were all treated with extraction of the four first premolars. Cephalometric radiographs were used to measure airway dimensions, and dental casts were used to measure the changes in the arch dimensions. A paired t-test was used to detect differences at P < .05. Results: The results showed statistically significant reductions in tongue length (P < .05), posterior adenoids thickness (AD2-H) (P < .05), upper and lower incisor inclination, and lower incisor to A-Pog line (P < .001). Considering the dental cast results, statistically significant reductions in upper arch length, lower arch length, and lower intermolar width were also found (P < .001). The only statistically significant increase was recorded for the upper intercanine width (P < .001). Conclusions: Extraction of the first premolars for the treatment of bimaxillary proclination does not affect upper airway dimensions despite the significant reduction in tongue length and arch dimensions. (Angle Orthod. 2012;82:853-859.)