Uvulo-glossopharyngeal dimensions in non-extraction, extraction with minimum anchorage, and extraction with maximum anchorage.

The aim of this study was to investigate upper respiratory airway dimensions in non-extraction and extraction subjects treated with minimum or maximum anchorage. Lateral cephalograms of 39 Class I subjects were divided into three groups (each containing 11 females and 2 males) according to treatment procedure: group 1, 13 patients treated with extraction of four premolars and minimum anchorage; group 2, 13 cases treated non-extraction with air-rotor stripping (ARS); and group 3, 13 bimaxillary protrusion subjects treated with extraction of four premolars and maximum anchorage. The mean ages of the patients were 18.1 ± 3.7, 17.8 ± 2.4, and 15.5 ± 0.88 years, respectively. Tongue, soft palate, hyoid position, and upper airway measurements were made on pre- and post-treatment lateral cephalograms and the differences between the mean measurements were tested using Wilcoxon signed-ranks test. Superior and middle airway space increased significantly (P < 0.05) in group 1. In group 2, none of the parameters showed a significant change, while in group 3, middle and inferior airway space decreased (P < 0.01). The findings show that extraction treatment using maximum anchorage has a reducing effect on the middle and inferior airway dimensions.