A Three-dimensional Study On Upper Airway And Hyoid Bone In Adult Skeletal Class Ⅱ And High Angle Patients

ObjectiveTo compare the characteristics of the upper airway and hyoid bone in adult skeletal ClassⅡand high angle patients and the difference between classⅡand class Ⅰskeletal patterns by CBCT,discuss the effect of the gender and the position of the maxilla and mandibular on upper airway and explore its mechanism.In order to evaluate the shape of upper airway and hyoid position before orthodontic treatment,provide theoretical fundation for making rational and effective clinical treatment plan and prevent the happening of OSAHS.MethodsFrom the CBCT data taken by the Department of Radiology of Henan Provincial Stomatological Hospital from 2015 to 2018,according to the inclusion criteria and grouping requirements,adult skeletal classⅡhigh angle patients were randomly selected and divided into the maxillary protrusion mandibular normal group,the maxillary normal mandibular posterior group,and the double jaw retraction group,and the skeletal class I high angle group was used as the control group,30 cases in each group,half male and half female,The CBCT images before treatment were collected and imported into Invivo5.2 software for 3D reconstruction.The volume of the pharynx,the volume of the pharynx,the cross-sectional area of the narrowest region,the sagittal diameter,the transverse diameter,the vertical height,and the tongue were recorded.The vertical and horizontal position of the bone relative to the plane of the anterior skull base was statistically analyzed using the SPSS 20.0 software package.Results1.There is a significant gender difference in upper airway morphology and tongue position in patients with skeletal classⅡhigh angle.The volume,minimum cross-sectional area,sagittal diameter,height of the upper airway pharyngeal segment and the level of the hyoid bone relative to the skull base are Vertical distance is greater than female.2.Results of upper airway morphology: volume,minimum cross-sectional area,sagittal diameter and transverse diameter of palatopharyngeal and hypopharyngeal airway are skeletal classⅠgroup > skeletal classⅡmaxillary prominence group >The mandibular retraction group> double jaw retraction group;however,there was no significant difference in the height of the palatopharyngeal and hypopharyngeal airway between each group.3.Results of the position of the hyoid bone: the horizontal position of the hyoid bone relative to the skull base: skeletal classⅠgroup > skeletal classⅡmaxillary prominence group > mandibular posterior group > double jaw retraction group;tongue bone relative to the skull base There is no difference between the groups in the vertical position.4.The volume,minimum cross-sectional area and horizontal position of the upper airway pharyngeal segment were positively correlated with SNB,and had no significant correlation with SNA and ANB.Conclusions1.The upper airway shape and hyoid bone position of adult skeletal classⅡ high angle patients have gender differences.Men are longer and wider than female upper airway,and the position of hyoid bone is more forward and lower.2.The upper airway morphology and hyoid bone position of adults with skeletal classⅡhigh angle are significantly different from those of skeletal classⅠ.3.The morphology of oropharyngeal airway and the position of hyoid bone in skeletal classⅡare related to the sagittal growth pattern of the upper and lower jaw.It is mainly affected by the development and position of the mandible,but it has no obvious correlation with the relative position of the upper and lower jaw.