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 II1 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.
Highlights
Many studies evaluated the pharyngeal flow dynamics response followed by the morphological changes in adult patients with OSAS11–13
Vos. et al measured the anatomical properties and simulated the airway flow of the upper airway in obstructive sleep apnea syndrome (OSAS) patients, and confirmed that there exists a relationship between the morphological parameters of the upper airway and apnea hypopnea index (AHI) in these patients[14]
Thirty growing patients (13 boys and 17 girls, mean age 11.57 ± 0.94 years, Body mass index (BMI) 17.86 ± 1.25) who were diagnosed as class II1 malocclusion with mandibular retrognathia and have finished TB treatment were randomly selected as TB group
Summary
Many studies evaluated the pharyngeal flow dynamics response followed by the morphological changes in adult patients with OSAS11–13 They reported that the upper airway resistance is inversely correlated with the pharyngeal dimension. Computational Fluid Dynamics (CFD) is an appropriate method in analogue simulating the flow field characteristics of the upper airway. It could accurately calculate the functional parameters such as pressure drop and flow resistance before and after treatment based on the patient specific geometrical models of the upper airway derived from 3D imaging technology[16,17,18]. The objective of this study is to evaluate the pharyngeal airflow response to TB treatment in growing patients with class II1 and mandibular retrognathia by means of CFD analogue simulation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
