Mouth breathing dries out the oral tissues, including the gums, teeth and airway. This leads to tonsil inflammation and formation of tonsil stones, bad breath, dry throat & difficulty swallowing without something to wash food down, and increased cavities and gingivitis. A lips-apart posture = a low tongue, which perpetuates mouth-breathing and poor palatal development during childhood.

Individuals with mouth-breathing often have a strong gag reflex on the tongue. A fully integrated gag reflex exists only in the esophagus, not on the tongue.