Fig 1.
Three-dimensional reconstruction of a patient’s upper airways.
(A) Three-dimensional reconstruction of a patient’s upper airways without an oral appliance, with a focus on the pharynx region. (B) The same patient’s upper airways with an oral appliance, with a focus on the pharynx region.
Fig 2.
Three-dimensional mesh model of the upper airways.
A tetrahedral unstructured mesh with a grid number of more than 1.65 million and less than 2 million was created for CFD calculations. This mesh density can capture the subtle parameter changes of the gas flow in the upper respiratory tract.
Fig 3.
Selected sections of the CFD model.
(1) the beginning of the nasopharynx; (2) the upper bound of the palatopharynx; (3) the upper bound of the glossopharynx; (4) the top of the epiglottis; (5) the base of the epiglottis.
Table 1.
Volumetric changes in the airways with and without the OAs (cm3).
Table 2.
Changes in the cross-sectional area of selected upper airway sections from patients with and without OAs (cm2).
Fig 4.
Velocity vectors in the mid–sagittal plane of a patient’s upper airways.
Before treatment, the airflow velocity was turbulent, while it became smooth and steady after using OAs. The maximum airflow velocity in the lower boundary of the palatopharyngeal, the narrowest part of the pharynx, was determined both pre- and post-treatment.
Table 3.
Airflow velocity changes in different selected sections of the upper airways form patients with and without the OAs (m/s).
Fig 5.
Pressure contours in the mid–sagittal plane of a patient’s upper airways.
The pressure distribution in the upper airway became steady after treatment. Both the initial and final minimum pressure was detected at the narrow region in the upper airway, i.e. the lower boundary of the palatopharynx.
Table 4.
Pressure changes in different sections of the upper airways from patients with and without OAs(Pa).
Table 5.
Changes of resistance in the pharynx of patients with and without OAs.
Table 6.
The changes of AHI, pharyngeal volume and pharyngeal resistance in OSAHS Patients with and without OAs.
Fig 6.
The correlation analysis among AHI, pharyngeal volume and pharyngeal resistance changes.
(A) There was a negative correlation between pharyngeal resistance changes and pharyngeal volume changes (r = -0.786 p = 0.0218). (B) There was a negative correlation between pharyngeal volume changes and AHI changes (r = -0.81 p = 0.0158). (C) There was a positive correlation between pharyngeal resistance changes and AHI changes (r = 0.976 p = 0.0008).