Gingivitis, dental caries and malocclusion are often seen associated with mouth breathing. The purpose of this study is to reveal relation between mouthbreathing signs and nasal obstruction. Clinical observation was carried out on mouth breathing signs and on nasal obstruction in cases of 136 school children (11-12 years old).
(1) Mouthbreathing signs were seen about half of children and correlated with each other except lack of uvular reflex.
(2) 50.7% had some nasal and pharyngeal obstruction. 11.0% were nasal respiration stopped at the time examined and 39.7% had nasal and pharyngeal diseases tending to cause stop of nasal respiration.
(3) Nasal and pharyngeal obstruction and oral signs of mouthbreathing were related each other. However correlation between lip-seal insufficiency and oral signs of mouthbreathing was seen more closely.
