What causes mouth breathing? Well parents will tell you that children struggle to breathe through their noses during a cold. So, for kids that are sick frequently, often their sinuses aren't adequately cleaned and they never regain that nasal breathing habit. Cleaning your child's nose is as important as cleaning their teeth (in my opinion). Nasal breathing is important for respiratory immune health, sleep, and the growth of the jaw. The nasal lining serves an important role in the innate immune