Airway Cephalometric Analysis Of Three Sagittal Skeletal Patterns During Teenager’s Rapid Growth Period

Objective:To compare the upper airway’s development characteristics and differences of three sagittal skeletal patterns during a teenager’s four rapid growth periods(acceleration,peak, late peak and end), by measuring the upper airway in lateral cephalogram, thus to provide references for the upper airway structure’s influences on three different sagittal skeletal patterns and their respective pathogenesis, the clinical diagnosis and development of cranial facial positions.Methods:To select three groups of skeletal statistics totaling 120 examples according to inclusion criteria: Type Ⅰ(ANB 0.7°-4.7°), Type Ⅱ(ANB>4.7°)and Type Ⅲ(ANB<0.7°). Then categorize the skeletal patterns into four categories according to cervical vertebral bone age quantitative classification method: the acceleration, peak,late peak and end period, each group with 30 examples. To analyze with variance and test LSD-t of different groups by using 15 items as upper airway criteria.Results:1.The measured values of three different groups of sagittal skeletal patterns in the acceleration period,The ∠PNSBa S(Ⅱ<Ⅰ<Ⅲ)and ANB angle show a negative correlation between them. The ∠Ba SN(Ⅱ>Ⅰ>Ⅲ)and ANB angle show a positive correlation between them. According to PNS-ad1, PNS-R and PNS-ad2, it has been shown that Type Ⅱand Type Ⅲ are bigger than Type Ⅰ; hyoid bonepositions show no difference in this period.2.The measured values of three different groups of sagittal skeletal patterns in the peak periodThe measured values of ∠Ba SN, AA-PNS and NA all decrease when ANB angle reduces, so are values of all S-PNS, ho-PNS, Ba-PNS, AA-PNS, PNS-ad1,PNS-R and PNS-ad2, which show a disparity in three nasopharyngeal airways,however the hyoid bone positions show no difference in this period.3.The measured values of three different groups of sagittal skeletal patterns in the late peak period Type Ⅱand Type Ⅲ are bigger than Type Ⅰin the S-PNS measured value. The values of AA-PNS decreases when ANB angle reduces(Ⅱ>Ⅰ>Ⅲ). The values of PNS-ad1, PNS-R and PNS-ad2 show that Type Ⅱand Type Ⅲ are bigger than TypeⅠ(Ⅱ>Ⅲ>Ⅰ). That the value of H-FH decreases when ANB angle reduces(Ⅱ>Ⅰ>Ⅲ) shows a difference of hyoid bone height in different skeletal patterns.4.The measured values of three different groups of sagittal skeletal patterns in the end periodThe values of U-MPW and V-LPW show that Type Ⅰand Type Ⅱ are smaller than Type Ⅲ. The values of H-C3 show the same outcome, which identifies that hyoid bone position differs in different skeletal patterns.5.Measured values contrast of three different airway sagittal skeletal patterns during a teenager’s growth periodNo remarkable differences show in three skeletal patterns of the ∠Ba SN and AA-PNS measured values during the peak period, identifying that cranial base and sagittal diameter has already stabilized in the pre-growth period.Conclusions:1.Skeletal structure is the basis of nasopharyngeal airways. A teenager’s sagittal nasopharyngeal airway has already formed before his/her rapid youth growth, then primarily is perpendicular growth. The measured values of cranial base andnasopharyngeal angle with three skeletal patterns are highly related to the angle of ANB. There is also speed disparity in nasopharynx with different skeletal patterns.2.With youth growth going, the hyoid bone positions go down gradually. There is no statistical significance in the front and rear position of hyoid bones with three different skeletal patterns during the four periods.3.The soft tissue and airway profile change with a teenager’s youth growth. At first the lower edge of nasopharynx adenoid is convex, then becomes concave with a teenager’s gradual growth and development.