فهرست نشریات علمی دسترسی آزاد ایران

Aim: The aim was to determine the effect of first premolars’ extraction with maximum incisor retraction on airway magnitude and hyoid bone position in cases with bimaxillary dentoalveolar protrusion.Methods: Lateral cephalograms of patients with Class I skeletal and dental relationships were retrospectively recruited. Inclusion criteria were 15‒30-year-old patients with bimaxillary proclination, who had undergone all first premolar extraction with maximum incisor retraction. Patients with dentofacial anomalies, chronic mouth breathing, and those who had undergone tonsillectomy or adenoidectomy were excluded. Pre- and post-treatment lateral cephalograms were digitally analyzed for airway measurements and hyoid bone position. Paired-samples t-test was used for statistical analysis. P<0.05 was considered statistically significant.Results: Thirty-three patients, comprising 22 females and 11 males, with a mean age of 24.39±6.92 years, were included. Statistically significant differences were found in airway dimensions from pre-treatment to post-treatment; upper airway size between soft palate and posterior pharyngeal wall (SPP-SPPW) decreased by 1.91 mm (12.78%), at uvula and middle posterior wall (U-MPW) by 2.51 mm (20.60%), at tongue base to posterior-inferior point on middle pharyngeal wall (TB-TPPW) by 3.39 mm (24.26%), and vallecular to lower pharyngeal wall by 1.51 mm (9.94%). The vertical position of the hyoid bone also decreased significantly, as indicated by the inferior movement of hyoidale (H) by 4 mm (3.8%). There were no significant changes in the horizontal position of the hyoid bone.Conclusion: Premolar extraction with maximum retraction in bimaxillary protrusion cases can decrease the airway dimension and increase the vertical position of the hyoid bone.