The Primary Investigation Of The Characteristics Of The Growth Of The Upper Airway In Skeletal Class Ⅲ Patients

Among all kinds of common malocclusion,skeletal class Ⅲ is one of them,and it would affect the oral function and appearance of patients.Comprehensive diagnosis and treatment of the facial skeleton and occlusion requires an understanding of all functional variables,including the upper airway.Upper airway,a nonuniform tube,around it is the sclerous and soft tissue.Numerous reports have shown that something is related between the characteristics of the upper airway and the facial morphology and malocclusion:Craniofacial abnormalities would make an influence on the upper airway,abnormalities of upper airway in turn would affect the morphology and structure of craniofacial.When it comes to the study of characteristics of upper airway,patients with Class Ⅲ malocclusion are somewhat neglected compared with those with a Class Ⅱ skeletal pattern.ObjectiveIn order to establish the reference for upper airway values based on different bone ages and for the growth of the craniofacial,the study would investigate the characteristics of the growth of the upper airway in skeletal class Ⅲ patients according to quantitative cervical vertebral maturation(QCVM),which would help the ortho-dentists with the diagnosis of malocclusion.Material and methods MaterialThis study is a retrospective one.The subjects in this study included 430 patients with Skeletal Class Ⅲ malocclusion,which received treatment in the Department of Orthodontics,the stomatological hospital of the Fourth Military Medical University from January in 2013 to July in 2015.Because of the reasons that the head posture of cephalometrics does not meet the requirements and the cervical vertebral body image is not clear,initial sample only consisted of 368 patients.Methods1.According to Quantitative Cervical Maturation(QCVM),patients selected were divided into 4 groups: stage I(accelerated phase),stage Ⅱ(peak period),stage Ⅲ(deceleration stage)and stage Ⅳ(end stage).Seven indexes of upper airway and four indexes of craniomaxillofacial structure were selected.The X-ray lateral radiographs were traced and recorded via Wincelph 9.0 software.2.SPSS19.0 software was performed to analyze the data.Measurements of the two independent sexes in the same stage were tested by T test,as well as the measurements of two independent stages of the same sex.The Pearson correlation analysis was performed for the relevance between the upper airway morphological index and craniomaxillofacial index.And the difference between the two groups of different vertical facial types was analyzed by one-way ANOVA and LSD-t.The levels of statistical significance were α=0.05,P <0.05,** P <0.01,*** p <0.001.Results1.The effect of age on the upper airway: For men,from stage Ⅰ to stage Ⅲ,the upper airway PNS-R,PNS-AD2,V-LPW increased significantly(P <0.05),SPP-SPPW,U-MPW and TB-TPPW increased gradually from stage Ⅱ to stage Ⅲ(P <0.05),and PNS-UPW increased significantly from stage Ⅰ to stage Ⅱ(p <0.01).For women,the upper airway PNS-R,PNS-AD2 increased significantly(P <0.01).The levels of SPP-SPPW,U-MPW,TB-TPPW and V-LPW were significantly increased from stage Ⅰ to stage Ⅲ(P <0.05),PNS-UPW increased significantly from stage Ⅰ to stage Ⅱ(p <0.05).The measured values were unchanged from stage Ⅲ to stage Ⅳ(p>0.5).2.The effect of gender on the upper airway: There was no gender difference for patients of QCVM Ⅰ(p>0.05)and those of QCVM Ⅱ,Ⅲ,Ⅳ(p>0.05)except the level of V-LPW(p<0.01).3.The relevance between the sagittal depth of upper airway and craniofacial structure: SPP-SPPW,U-MPW is associated with SNA,SNB,Go Gn-SN;tongue pharyngeal TB-TPPW is associated with SNB,ANB,GoGn-SN;V-LPW is associated with SNB,GoGn-SN,ANB,Pearson correlation coefficient was only 0.2-0.3.4.The variance analysis showed that the effect of vertical facial type on oropharynx and pharynx was statistically significant(p <0.05).LSD-t test results showed that: for each measurement,the lowest is value of patients with high angle,followed by patients with average angle and patients with a low angle,in addition to PNS-UPW segment among the three groups are different,the rest only was statistically different between the high angle and the low angle group.Conclusion1.From children to young adults,the upper airway measurements have increased.2.There was no significant gender difference in upper airway measurements except V-LPW in stage Ⅱ,Ⅲ,and Ⅳ.3.The upper airway space and craniomaxillofacial surface have a certain relationship and the two affect each other,the airway space should be considered as a factor when the ortho-dentists make a treatment plan.4.For patients with skeletal class Ⅲ,the vertical facial type will affect the upper airway space,high angle patients with the smallest space.