Comparison of Pharyngeal Airway and Dentoskeletal Effects of 2 and 4 Premolar Extraction Treatment in Adult Orthodontic Patients

Abstract

Objective: This study aimed to compare pharyngeal airway and dentoskeletal effects of 2 and 4 premolar extraction treatments in adult patients separately for each gender. Methods: The study was conducted with 60 adults (26 males; 34 females) aged 18-35 years. Individuals were divided into 3 groups as non-extraction, 2premolar extraction, and 4-premolar extraction. Pre-treatment (T0) and post-treatment (T1) dentoskeletal and pharyngeal airway measurements were performed on cephalometric radiographs. Results: A significant increase in nasopharyngeal airway (PNS-ad2) and anterior hyoid bone movement (CV3ai-H) was observed in the 4extraction group; whereas in the 2-extraction group, inferior oropharyngeal airway (IAS) narrowing and hyoid bone movement in posterosuperior direction were observed. In the non-extraction group, inferior oropharyngeal airway narrowing and hyoid bone movement in the anteroinferior direction were observed. A significant increase in nasopharyngeal airway, narrowing of oropharyngeal airway, and superior hyoid bone movement were observed in the 2-extraction group in males. In the non-extraction and 4-extraction groups, the hyoid bone moved in inferior and anterior directions, respectively. While the hyoid bone moved posteriorly in the 2extraction group in females, there was an increase in nasopharyngeal airway and narrowing of the middle oropharyngeal airway (MAS) in the 4-extraction group. Conclusion: While the nasopharyngeal airway was widened in individuals with 4-extractions, the inferior oropharyngeal airway was narrowed in both the 2extraction and non-extraction groups. Hyoid bone movement was observed in anterior, posterosuperior, and anteroinferior directions in 4-extraction, 2-extraction, and non-extraction patients, respectively, and these changes vary according to gender.