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Computational fluid dynamics simulation of the upper airway response to large incisor retraction in adult class I bimaxillary protrusion patients

View Article: PubMed Central - PubMed

ABSTRACT

The changes of the upper airway after large retraction of the incisors in adult class I bimaxillary protrusion patients were assessed mainly focused on the anatomic variation and ignored the functional changes. This study aimed to investigate the changes of the upper airway in adult class I bimaxillary protrusion patients after extraction treatment using the functional images based on computational fluid dynamics (CFD). CFD was implemented after 3D reconstruction based on the CBCT of 30 patients who have completed extraction treatment. After treatment, pressure drop in the minimum area, oropharynx, and hypopharynx increased significantly. The minimum pressure and the maximum velocity mainly located in the hypopharynx in pre-treatment while they mostly occured in the oropharynx after treatment. Statistically significant correlation between pressure drop and anatomic parameters, pressure drop and treatment outcomes was found. No statistical significance changes in pressure drop and volume of nasopharynx was found. This study suggested that the risk of pharyngeal collapsing become higher after extraction treatment with maximum anchorage in bimaxillary protrusion adult patients. Those adverse changes should be taken into consideration especially for high-risk patients to avoid undesired weakening of the respiratory function in clinical treatment.

No MeSH data available.


Related in: MedlinePlus

The pressure profile of the pharyngeal airflow in (a) pre- and (b) post-treatment, and the cross section every 5 mm along Z-axis in (c) pre- and (d) post-treatment.
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f5: The pressure profile of the pharyngeal airflow in (a) pre- and (b) post-treatment, and the cross section every 5 mm along Z-axis in (c) pre- and (d) post-treatment.

Mentions: Figures 5 and 6 showed the pressure and velocity distribution in upper airway for a representative patient. In the pre-treatment subjects, the pressure had no abrupt changes from the choana to the hypopharynx, and the minimum pressure and maximum velocity occurred in the hypopharynx. After extraction treatment, the pressure decreased from the choana to the hypopharynx, and the minimum pressure and maximum velocity occurred in the oropharynx. In addition, the mainstream of airflow with high velocity flowed along the posterior wall of the pharynx, while the flow velocity was lower in the anterior wall. The local swirls occurred mostly in the places with abrupt changes in morphology. The value of the ΔPmax, Or-ΔP, Hy-ΔP increased significantly after the extraction treatment (Table 1). The pressure drop in nasopharynx was statistically insignificant.


Computational fluid dynamics simulation of the upper airway response to large incisor retraction in adult class I bimaxillary protrusion patients
The pressure profile of the pharyngeal airflow in (a) pre- and (b) post-treatment, and the cross section every 5 mm along Z-axis in (c) pre- and (d) post-treatment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384277&req=5

f5: The pressure profile of the pharyngeal airflow in (a) pre- and (b) post-treatment, and the cross section every 5 mm along Z-axis in (c) pre- and (d) post-treatment.
Mentions: Figures 5 and 6 showed the pressure and velocity distribution in upper airway for a representative patient. In the pre-treatment subjects, the pressure had no abrupt changes from the choana to the hypopharynx, and the minimum pressure and maximum velocity occurred in the hypopharynx. After extraction treatment, the pressure decreased from the choana to the hypopharynx, and the minimum pressure and maximum velocity occurred in the oropharynx. In addition, the mainstream of airflow with high velocity flowed along the posterior wall of the pharynx, while the flow velocity was lower in the anterior wall. The local swirls occurred mostly in the places with abrupt changes in morphology. The value of the ΔPmax, Or-ΔP, Hy-ΔP increased significantly after the extraction treatment (Table 1). The pressure drop in nasopharynx was statistically insignificant.

View Article: PubMed Central - PubMed

ABSTRACT

The changes of the upper airway after large retraction of the incisors in adult class I bimaxillary protrusion patients were assessed mainly focused on the anatomic variation and ignored the functional changes. This study aimed to investigate the changes of the upper airway in adult class I bimaxillary protrusion patients after extraction treatment using the functional images based on computational fluid dynamics (CFD). CFD was implemented after 3D reconstruction based on the CBCT of 30 patients who have completed extraction treatment. After treatment, pressure drop in the minimum area, oropharynx, and hypopharynx increased significantly. The minimum pressure and the maximum velocity mainly located in the hypopharynx in pre-treatment while they mostly occured in the oropharynx after treatment. Statistically significant correlation between pressure drop and anatomic parameters, pressure drop and treatment outcomes was found. No statistical significance changes in pressure drop and volume of nasopharynx was found. This study suggested that the risk of pharyngeal collapsing become higher after extraction treatment with maximum anchorage in bimaxillary protrusion adult patients. Those adverse changes should be taken into consideration especially for high-risk patients to avoid undesired weakening of the respiratory function in clinical treatment.

No MeSH data available.


Related in: MedlinePlus