To compare the effects of extraction vs nonextraction orthodontic treatments on oropharyngeal airway volume.

An existing patient database was screened for pretreatment (T0) and posttreatment (T1) cone beam computed tomography (CBCT) scans and complete medical histories. Twenty patients treated with removal of four premolars (ExtG) and 20 controls (NExtG), were matched for age, gender, ethnicity, height, weight, body mass index, and oropharyngeal (OP) volumes, among other variables. Constructed lateral cephalograms (three skeletal and four dental variables) and OP volumes were measured at T0 and T1 using Dolphin Imaging 11.0. Independent sample t-tests were used to compare the groups at T0 and the outcome variables at T1. Paired sample t-tests were used to compare the mean changes from T0 to T1. Statistical significance was set at P ≤ .05.

Changes from T0 to T1 were found to be significant in both groups for CoA, CoGn, U1-FH, and IMPA. In the ExtG alone, U1-Na Perp and L1-Na Perp were also significantly different from T0 to T1. Despite the observed differences, no significant differences were found at the end of treatment between the mean OP volumes for either group (12,675.6 ± 4483.6 for ExtG; 12,002.7 ± 2857.0 for NExtG, P > .05). Similarly, the mean changes in OP volume (1082.6 mm³ and 1701.1 mm³ for ExtG and NExtG, respectively) and increase in mean minimal constricted axial areas (17.4 mm² and 1.9 mm² for ExtG and NExtG, respectively, P > .05) from T0 to T1 were not significant for the two groups.

Extraction of four premolars with retraction of incisors does not affect OP airway volume.