Assessment of oropharynx using cone beam computed tomography—Change in volume during oropharynx growth—

Recently airway blockage accidents have increased in Japan, and airway blockage accidents involving children account for 12% of the total. However, the causes of airway blockage accidents are not clear. The oropharynx plays an important role in feeding and swallowing by helping to prevent aspiration and airway blockage accidents. Few studies, however, detail the changes in volume of the oropharynx during growth. The relationship, therefore, between the volume of the oropharynx and growth was investigated in this study. The subjects, 50 males and 50 females aged 7 to 15 years, were grouped according to a dental development age index (Hellman Dental Age), resulting in a dental development range from IIC to IVA. Cone beam computed tomography (CB Mercuray, Hitachi) was used to scan each subject's head, and a three-dimensional modeling system was used to measure the oropharynx volume, height and other. The mean and standard deviation of the height of males was 35.48 ± 6.85 mm and of females, 34.78 ± 7.42 mm. In male and female subjects, the height of the oropharynx airway increased from IIC to IVA. The mean and standard deviation of the oropharynx volume of males was 5,570.79 ± 3,790.30 mm3 and of females, 4,942.80 ± 2,818.75 mm3. In male and female subjects, the volume of the oropharynx airway increased significantly from IIIC to IVA. Therefore, this study suggests that there is a strong relationship between the increase of the oropharynx airway and the time and condition of eruption of the second molar teeth from period of IIC to IVA of the Hellman Dental Age index.