Evaluating the relationship between dimensions of the upper airway and facial profile according to initial lateral cephalometric radiography in orthodontic patients in the north of Iran

Purpose

Decreased upper airway dimensions due to adenoid enlargement may have unfavorable aesthetic and/or functional effects on the soft or hard tissue profile development. The aim of this study was to investigate the associations between adenoid sizes to upper airway size ratio (airway ratio) in the midsagittal plane and various types of soft and hard tissue facial profile convexity.

Materials and methods

251 lateral cephalometric images of pre-orthodontic healthy subjects with age group of 6•12, 13•18, 19•25 and 26•29 years, were collected. They were classified into four subgroups based on the airway ratio (grade 1: <1/4 í 100), (grade 2: 1/4•1/2 í 100), (grade 3:1/2•3/4 í 100) and (grade 4: >3/4 í 100). The radiographs were characterized as convex, normal and concave soft tissue facial profile according to the facial convexity angle. Cephalometric analyses were done using Dolphin imaging computer software 11.95. Kruskal Wallis test was used to evaluate differences between airway ratio and facial morphologies; the mandibular plane angle was compared between airway ratio subgroups by Chi square.

Results

Airway ratio was not significantly different (P = 0.241) between soft tissue facial convexity subgroups and within age subgroups. Mandibular plane angle was in a significant relation within airway ratio (p = 0.028).

Conclusion

There was not any significant relation between decreased upper airway ratios and types of the soft or hard tissue facial profile convexity, however there was a significant relation between upper airway ratios and age subgroups. A significant revers correlation was seen between the mandibular plane angle and nasopharyngeal dimensions.