title: Analogue simulation of pharyngeal airflow response to Twin Block treatment in growing patients with Class II(1) and mandibular retrognathia.
abstract: The flow dynamics of respiratory airflow is the basic factor that influences the ventilation function of the upper airway. This research aimed to investigate the pharyngeal flow field characteristics after Twin Block (TB) treatment in growing patients with Class II(1) and mandibular retrognathia by computation fluid dynamics (CFD) simulation. Cone beam computed tomography (CBCT) scans of patients who have completed TB treatment (n = 30) and about to accept TB treatment (n = 30) were reconstructed. After CFD simulation, correlations between the pharyngeal pressure drop and morphological parameters were further analyzed. During inspiration, we found that the pressure minimum occurred in the hypopharynx, while the maximum pressure drop and velocity was located in the oropharynx. After TB treatment, the oropharynx and hypopharynx showed significant differences in airflow features, and the most obvious change was observed in the oropharynx. A significant correlation was discovered between the change amount of oropharyngeal pressure drop and volume (r = 0.694, p = 0.001), mean cross-sectional area (r = 0.859, p = 0.000), and ratio of the minimum and mean cross-sectional area (r = 0.898, p = 0.000) of the oropharynx. Our research suggested that the pharyngeal airflow characteristics response positively to mandibular advancement with the enlargement in volume, cross-sectional area and more uniform oropharyngeal area distribution.
authors.affiliation: Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China.|Department of Orthodontics, Yantai Stomatological Hospital, Yantai, 264000, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China.|Department of Stomatology, Weifang People's Hospital, Weifang, 261041, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.affiliation: Department of Stomatology, the Affiliated Hospital of Qingdao University, Qingdao, 266000, China.
authors.forename: Guijun
authors.initials: G
authors.lastname: Yan
authors.affiliation: Department of Orthodontics, Yantai Stomatological Hospital, Yantai, 264000, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.affiliation: College of Stomatology, Shandong University, Jinan, 250012, China.
authors.forename: Guojv
authors.initials: G
authors.lastname: Li
authors.affiliation: College of Stomatology, Shandong University, Jinan, 250012, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Orthodontics, College of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, 250012, China.
authors.forename: Dongxu
authors.initials: D
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D057446:Hydrodynamics; D008297:Male; D009967:Orthodontic Appliances; D010614:Pharynx / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D015656:Respiratory Mechanics; D063173:Retrognathia / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*