Cone-beam Computed Tomography Evaluation Of Nasomaxillary Complex And Upper Airway Following Rapid Maxillary Expansion

Objective: This study was designed to evaluate the treatment effects of rapid maxillary expansion(RME)on nasomaxillary complex and upper airway in growing patients in the short term by using cone-beam CT and Dolphin software,and to take a further analysis of the coordination of the changes between nasomaxillary complex and upper airway,to provide experimental results to help orthodontic clinic diagnosis and treatment.Methods: 30 subjects(8 male,22 female,with a mean age of13.14±1.45 years)were selected from Orthodontic Department of Guiyang Stomatological Hospital,who were treated with Hyrax rapid maxillary expansion,CBCT scans were taken before and after RME.Using Dolphin software for image processing,three-dimensional reconstruction,fixing point and measuring.Chose coronal images to measure the liner distance between the buccal sides of the canine teeth,the first premolars,first molars,and distance between the root apexes.The anterior and posterior nasal cavity were taken,measuring the distance between the base width and the nasal lateral wall of nasal cavity.Measuring the median sagittal plane of the posterior nasal spine,second and third cervical plane of the sagittal diameter,coronary diameter,cross-sectional area,the segment volume and height,and so on.SPSS software package(Version19.0,SPSS,Chicago,USA)was used for data analysis and paired t-test was used for statistical analysis,to evaluate the changes of the morphology of nasomaxillary complex and upper airway following the RME.Results: After RME treatment,all of the transverse skeletal(lateral nasal width,and maxillary width)and interdental(intermolar,interpremolar,and intercanine)parameters were significantly enlarged(P<0.05).The nasopharyngeal airway surface area and the volume was increased,and the difference was statisticallysignificant(P<0.05).Oropharyngeal and hypopharyngeal airway surface area and volume had no obvious change.Each airway height also had no obvious change.Conclusion: During the growth period of maxillary transverse deficiency after RME treatment,this treatment creates a significant increase in the naso-maxillary complex width and nasal passage volume in a short-term,but no significant change is observed in the oropharyngeal and hypopharyngeal airway.