• Bancha Pornsuksiri D.D.S. (Hons)
• Chintana Sirichompun D.D.S. (Hons), M.D.Sc. (Orthodontics), Diplomate, Thai board of Orthodontics
• Soontra Panmekiate D.D.S., M.D.Sc., Odont. Dr.

Objective To obtain mean and compare upper airway dimensions in a group of Thai orthodontic
patients with different skeletal types.

Materials and methods Lateral cephalometric radiograghs of 327 patients, aged 16-40 years, treated
in the Orthodontic Department, Faculty of Dentistry, Chulalongkorn University were divided into two
groups. Group 1 was a normal bite group; 167 patients, which were divided into three subgroups:
skeletal Class I, II and III. Group 2 was a skeletal Class I group; 152 patients, which were divided into
3 subgroups: skeletal deep bite, normal bite and open bite. Upper airway dimensions were measured
with INFINITT program and IMAGE TOOL program. To compare mean of the upper airway
dimensions among subgroups, one-way ANOVA was analyzed at 0.05 significant level.

Results In Group 1, a significant reduction of upper airway dimensions in oropharynx and hypopharynx
was found in skeletal Class III, I and II, respectively. In Group 2, a significant reduction of upper
airway dimensions in nasopharynx, oropharynx and hypopharynx was found in skeletal deep bite,
normal bite and open bite, respectively.

Conclusion Thai orthodontic patients with different vertical or antero-posterior skeletal types have
different upper airway dimensions.

(CU Dent J. 2013;36:9-20)