| Objective:To observe the changes of dimensions of the upper airway and the distribution of the position of the minimum axial area in different genders during growth and development using CBCT analysis.Materials and Methods:CBCT imaging data of untreated patients aged 6-21 years continuously from July 2017 to January 2020 were collected from the Stomatological Hospital of Shandong University.The inclusion criteria were 1.9°?ANB?7.5°in the replacement period and-1.3°?ANB?6.7°in the permanent tooth period.There were 100 male cases and 100 female cases in each age group,a total of 1000 cases.The upper border of the visual field in CBCT images included at least the skull base and the lower border at least the upper border of the fifth cervical vertebra.Dolphin 11.8 was used to measure the volume of the upper airway and the volume of each section,as well as the total area of the midsagittal plane and the of each section.Furthermore,the height variation between the apex of the second cervical vertebra and the most anterior superior point of the fifth cervical vertebra,the minimum axial area of the upper airway and its position distribution were also observed.SPSS 26.0 was used for statistical analysis of the measurement results.Microsoft Excel was used to plot the changes of related items with age.Result:The dimensions of the upper airway changed with the growth and development,and there were significant differences between different genders.1.Volume of upper airway1.1 Total volumeTotal volume increased rapidly in both male and female patients from 6 to 15 years old.There was a sudden accelerated increase in males from 15 to 18 years old,while the growth rate of females was slower than before,so that the upper airway volume of females(26.03±5.62cm3)was significantly lower than that of males(31.16±7.22cm3)after entering the adult stage.The total volume tended to be relatively stable in both males and females between 18 and 21 years old.The upper airway volume of adult females was significantly smaller than that of males(26.53±5.39cm3:31.13±7.23cm3).1.2 The volume of each segment of the upper airway1.2.1 Volume of nasopharynxIn males,volume of nasopharynx underwent a series of changes from 6 to 21 years old,with the growth rate from fast,slow,rapid,slow to the slowest,until the age of 21 years old was still not stable.The results of females showed a uniform growth rate from 9 to 18 years old,and a slow but not steady growth rate from 18 to 21 years old.By age 21,the nasopharyngeal volume of males and females were basically the same(7.40±1.75cm3:7.40±1.90 cm3).1.2.2 Volume of palatopharynxIn males,volume of palatopharynx from 6 to 21 years of age went through the stages of accelerating,slowing,and then stabilizing.However,the volume of females increased linearly from 9 to 15 years old,and the growth rate slowed down from 15 to 18 years old,and the growth rate was significantly lower than that of the male in the same age stage,and then stabilized from 18 to 21 years old.The palatopharynx of adult females is slightly smaller than that of males(5.64±2.03cm3:6.03±2.13cm3).1.2.3 Volume of glossopharyngeumThe growth and development of male glossopharynx is consistent with that of palatopharynx.The growth rate of female glossopharynx was the fastest at 9-12 years old,which was faster than that of male in the same age group.The growth rate slowed down at 12-18 years old,which was slower than that of male in the same age group,and then stabilized at 18-21 years old.The glossopharynx of adult females was significantly smaller than that of males(4.59±2.06cm3:6.23±2.84cm3).1.2.4 Volume of laryngopharynxThe growth rate of Volume of laryngopharynx in males was slower from 9 to 12 years old,increased rapidly from 12 to 18 years old,and was basically stable from 18 to 21 years old.In female,volume of laryngopharynx increased rapidly from 9 to 15 years old,the growth rate of 15 to 18 years old was significantly lower than that of male in the same age stage,and it tended to be stable from 18 to 21 years old.The difference in volume growth between females and males aged 15-18 years resulted in the laryngopharynx of the former being significantly smaller than that of the latter(8.90±2.15cm3:11.47±3.59cm3).2.2 Mid-Sagittal plane areaThe total area of the mid-sagittal plane of the upper airway and the variation rule of each sectional area were basically consistent with the volume,but the variation range was smaller.2.3 The height of mid-sagittal plane2.3.1 Height of palatopharynxThe change of height of palatopharynx in males aged from 9 to 21 years experienced the slowest growth rate,rapid increase and slightly slower growth rate.The growth rate of females aged from 9 to 12 years was higher than that of males of the same age.The growth rate of 12 to 15 years old was the fastest,which was consistent with that of male in the same age stage.The growth rate of 15-21 years old was slow,which was lower than that of male of the same age.The palatopharyngeal height of adult females was less than that of males(22.40±2.99mm:24.88±3.17mm).2.3.2 Height of glossopharyngeumThe height of glossopharyngeum in males increased rapidly from 9 to 12 years old,the growth rate slowed down from 12 to 15 years old,and the growth rate accelerated again from 15 to 18 years old,until it became stable from 18 to 21 years old(23.03±5.20mm?23.64±5.08mm).The height of glossopharyngeum in females increased rapidly from 9 to 12 years old,increased rapidly from 12 to 15 years old,and decreased sharply from 15 to 18 years old,which was significantly lower than that in males of the same age,and decreased slightly from 18 to 21 years old.After entering the adult stage,the height of glossopharynx in females was significantly lower than that in males(20.12±4.25mm:23.64±5.08mm).2.3.3 Height of laryngopharynzThe growth rate of height of laryngopharynx in males aged at 9-15 years was slower,while that in males aged 15-18 years was faster and reached a peak of 36.74±6.87mm,while that in males aged 18-21 years was smaller(36.74±6.87mm?31.22±6.38mm).The height of laryngopharynx in females decreased slightly from 9 to 12 years old,and showed steady state from 12 to 18 years old,while significantly increased from 18 to 21 years old(29.82±5.50mm?34.85±7.83mm).The height of laryngopharynx in females was not consistent with the developmental rule of male at the same age.3.The height from the apex of the second cervical vertebra to the level of the most anterior superior point of the fifth cervical vertebraThe height of cervical vertebra in males aged 9-15 increased rapidly and the fastest,but the growth rate was slightly slower at 15-18 years of age,and tended to be stable in males aged 18-21.The growth rate of females from 9 to 15 years old was basically the same as that of males in the same age stage,and it did not increase significantly from 15 to 21 years old and reached a stable rate earlier.In adulthood,the height of cervical spine in females was significantly lower than that of males(72.51±5.12mm:79.1 5±4.82mm).4.Normal range and location distribution of the minimum axial area at all ages4.1 Changes of the minimum axial area with growth and developmentMales:6-9 years old 57.04±14.5mm2;9-12 years old 77.24±25.54mm2;12-15 years old 110.58±42.56mm2;15-18 years old 158.13±58.46mm2;18-21 years old 148.40±59.30mm2.Females:6-9 years old 58.50±17.19mm2;9-12 years old 83.85±29.39mm2;12-15 years old 116.05±42.66mm2;15-18 years old 136.67±38.43mm2,18?21 years old 132.02±43.40mm2.The minimum axial area of male and female increased significantly with growth and development from 6 to 18 years old,and tended to peak from 15 to 18 years old.Although the minimum cross-sectional area of males was significantly greater than that of females at ages 15-21,both of them showed the same decreasing trend at ages 18-21.4.2 Position distribution of the minimum axial areaThe minimum axial area was mostly located in laryngopharynx(male:65%,female:81%)at the age of 6-9 years,and moved towards oropharynx with growth and development.From 18 to 21 years old,the position located in oropharynx in males accounted for 80%,and that of females accounted for 63%.Conclusion:1.The dimension of the upper airway increased with growth and development,and the increase was non-linear,reaching its peak between 15 and 18 years of age and becoming stable in adulthood.2.The upper airway size of males and females varied in various stages of growth and development.Both the rapid increase period and the stable period appeared earlier in females than in males.Adult females generally had a smaller upper airway than males.3.The location of the minimum axial area tended to move towards oropharynx with the growth and development.For adults,the location of minimum axial area of females was lower than that of males. |
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