Longitudinal Cephalometric Study of Naso-and Oropharyngeal Growth

Objectives: The purpose of this study was to evaluate the growth of the soft tissue of the naso- and oropharynx airway.
Methods: This is a mixed-longitudinal study using lateral cephalograms obtained from the University of Michigan Elementary and Secondary School Growth Study. The sample consisted of 2917 lateral cephalometric radiographs from 678 subjects (326 males and 352 females) age 4 to 17 years. Conventional lateral cephalometric hard tissue and soft tissue naso- and oropharynx landmarks were digitized and analyzed to assess growth changes in the width of the naso- and oropharynx airway.
Results: The results of quantitative analyses showed the majority of skeletal linear measurements increased with time. Nasopharynx airway width (distance from the superior soft palate to the pharyngeal wall) also increased steadily from 7.3 mm to 15.4 mm from age 4 to 17 years. However, the lower part of oropharynx width at tongue base (OrP_T) and the tip of the soft palate (OrP_I) were different from those seen for the skeletal hard tissue and nasopharynx measurements. Oropharynx airway width at the tongue base level (OrP_T) decreased from 14.9 mm to 11.9 mm from ages 4 to 14 years and increased only about 0.5mm after that, between ages 14 and 17 years. No significant difference was observed in the oropharynx width between male and female until age 16 years; Both OrP_T (p=0.002) and OrP_I (p=0.003) at age 17 years were larger in males. No apparent growth peak was observed in naso- and oropharynx widths.
Conclusions: The results of this study suggest that the nasopharynx increases steadily from ages 4 to 17 years. Oropharynx airway width at the tip of the soft palate decreased from ages 4 to 14 years and remained relatively stable, ranging 11-12mm from ages 14 to 17 years.