Effect Of Maxillary Protraction On Upper Airway And Surrounding Structures In Patients With Skeletal Ⅲ At The Peak Of Growth

Objective: According to the quantitative stage staging of cervical vertebrae,the patients with skeletal class Ⅲ at the peak of growth and development were selected to further explore the influence of maxillary anterior traction on the position of hyoid bone and soft palate and the sagittal diameter of nasopharynx,velopharynx,glossopharynx and hypopharynx.Correlation analysis of the upper airway and surrounding structures,improve understanding of the structure and structure of the head and neck region,and provide more reference for clinical orthodontic diagnosis and treatment planning.Materials and Methods: According to the experimental inclusion criteria,20 patients were treated in the orthodontics department of Dalian Stomatological Hospital affiliated to Dalian Medical University from September 2016 to February 2019,including 11 males and 9 females with an average age of 10.12±0.83 years old.Average treatment time 9.00 ± 0.70 months.Linear and angular measurements of the cranial and maxillofacial,hyoid,airway,and soft palate before and after treatment were compared and analyzed.The same machine(ORTHOPHOS,XG5,Sirona,Germany)was used for the imaging.The filming process ensured that the upper edge of the external auditory canal was parallel to the horizontal plane and told the patient to relax naturally when shooting the lateral slices of the skull.Do not swallow.Speak and chew,breathe evenly with your nose,tongue flat on the bottom of the mouth,teeth bite(interdigitated teeth),lips relaxed.To ensure that the head side film taken by each patient is fully exposed and the image is clear.Image and image are adjusted and optimized by professional PS software.WinCeph 9.0(US,RISE Co,Ltd.)is used for marker point,linear and angle measurement and cervical vertebra maturity evaluation.Specific measurement items include hyoid bone.Horizontal distance,vertical distance and angle,sagittal diameter of the upper airway,length,thickness,and angle of the soft palate.The test item is measured three times in succession by the same experimenter,and the average is taken as the final result.All data were statistically analyzed using SPSS version 21.0(SPSS Inc,Chicago,IL,USA): whether the Shapiro-Wilk test results were normal distribution;a paired t test was used to assess significant differences within the group;Pearson was used for correlation analysis.Result: 1.The maxillary protraction cranial and maxillofacial structures change significantly in the sagittal and vertical directions.2.The sagittal diameter of the nasopharynx and the velopharynx was significantly increased(p<0.05).3.The vertical distance of the hyoid bone(APH-MP,GOP-PPH)increased significantly(p<0.05);There was no significant difference in the horizontal distance of the hyoid bone and the angle of the hyoid bone before and after treatment(p>0.05);Head position(SN-CVT,SN-OPT)remained consistent before and after treatment(p>0.05);The length of soft palate(SPL)increased significantly(p<0.05).4.PNS-Ad1 was significantly correlated with Me-ANS(p<0.05)and was positively correlated;V-LPW was significantly correlated with MP-SN(p<0.05),showing a positive correlation;MPS,V-LPW,SPL,SPT were significantly correlated with SN-OPT and SN-CVT(p<0.05),showing a positive correlation;SPL was significantly correlated with Ptm-ANS(p<0.05),with a negative correlation.5.APH-MP was significantly correlated with MP-SN(p<0.05),showing a positive correlation;LAH-PP,LAH-OP and N-ANS were significantly correlated(p<0.01),negatively correlated.Conclusion: 1.Patients with skeletal class Ⅲ with maxillary hypoplasia undergoing orthodontic traction orthopedics can not only promote maxillary growth,improve facial coordination and soft tissue aesthetics,restore balance inside and outsidethe mouth.2.It also increase upper airway nasopharyngeal Segmental,vaginal sagittal diameter,improve the respiratory function of patients with maxillary hypoplasia.3.there is a significant correlation between the cranio-maxillofacial region and the hyoid bone and airway.There is a significant correlation between the airway and the hyoid bone,soft palate,and head position.