The Cbct Study Of Airway Morphology And Volume In Malocclusion Patients With Different Sagittal Facial Tapes

Obstructive sleep apnea hypopnea syndrome(OSAHS) is a sleep breathing disorder, which is characterized by frequent hypopnea and apnea for repetitive episodes of complete or partial obstruction of the upper airway during sleep. These conditions usually result in oxygen desaturation, lethargy, reduced concentrationand may give rise to hypertension, cardiac arrhythmia, Ⅱ diabetes and multiple organ system damage.The directly pathogenesis of OSAHS is narrowing and obstruction of upper airway. in the past decades, Many researches have done a lot of studies about upper airway morphology, function and impact factors, but most research has focused on the measuring only about line distance and area of airway using cephalometric analysis less on the study about volume and three-dimensional structure of airway. With the development of imaging technology in recent years, especially CT, MRI and3D projection equipment. The study of airway from the three-dimensional direction Become possible. Compared with conventional CT, CBCT More suitable to use in dentistry for these advantages:Less radiation dose; high spatial resolution; short scan time; costs low.To study the differences of three dimensional oropharyngeal airway morphology and volume in malocclusion patients with different sagittal facial types and to investigate the correlation between the craniofacial structures and the upper airway morphology. Cone beam CT datas of90adult malocclusion patients(18-40years) before orthodontic treatment were collected and divided into three groups of sagittal skeletal facial type according to the ANB angle,30cases in each group. Oropharyngeal airway volume, area, height, minimum section area and ratio of the sagittal dimension to transverse dimension of each patient were measured with Mimics10.01software, single factor variance analysis was used to compare the differences of three groups airway morphology and size in SPSS13.0software package.The findings:1. Oropharyngeal airway volume gradually become smaller as ANB angle increased, while height gradually become larger as ANB angle increased. The glossopharyngeal airway volume and mean cross-sectional area of Class Ⅱ patients were significantly smaller than class Ⅰ and class Ⅲ patients.2. The minimum cross-section of the oropharyngeal airway most located in the end of the soft palate or near the base of the tongue, oropharyngeal airway presents a narrow middle, two wide funnel-shaped form. There was statistical difference in minimum cross section area Among three sagittal facial types and minimum cross section area gradually become smaller as ANB angle increased.3. Minimum cross-section of the oropharyngeal airway presents a oval shape that the transverse dimension greater than the sagittal dimension. There was not statistical difference in the ratio of sagittal dimension to transverse dimension with the ANB angle changes, but the transverse dimension and sagittal dimension increased or decreased simultaneously.Based on these findings, it is concluded that the minimum cross-section of the oropharyngeal airway most located in the end of the soft palate or near the base of the tongue and The morphology of Oropharyngeal airway change from wide to narrow as ANB angle increased. Class Ⅱ patients with mandibular retrusion showed a significantly narrow oropharyngeal airway that is not conducive to smooth the airflow. Relative to other patients, Class Ⅱ patients more likely to have symptoms of OSAHS.