The black line shows recessive facial development typical of a mouth-breather. The red line shows facial balance that would result with good oral posture. The green line indicates the tilting back of the forehead to alleviate airway problems.
10-year-old boy developing normally; Center and far right: same boy at 17 years after becoming a mouth-breather.
An adequate airway is the most important factor in a child’s facial development. Genetics determine factors such as hair color, eye color and height. In contrast, altered oral posture determines whether or not the face will be well balanced.Often children grow up as mouth-breathers due to allergies, obstructions in the airway such as enlarged tonsils or adenoids, or sinus problems. Mouth-breathing allows the child to get the air he or she needs, but it alters “proper oral posture” and causes changes in the child’s growth pattern.(See Proper Oral Posture)
If a child grows up as a mouth-breather without proper oral posture, the growth tends to be in a downward and backward direction rather than a downward and forward direction. Downward and backward growth results in a long lower face and recessive chin. Different alterations in oral posture produce facial and tooth changes that are unique and different from the genetically determined pattern for an individual.
Pictured above is a 10-year old boy who was developing normally. He was a nose breather, had excellent oral posture and a balanced face. Not long after this picture was taken, he was given a gerbil that he kept in his room. Unfortunately, he was very
allergic to the gerbil and went from being a nose-breather to a mouth-breather. Note the changes in his face by the time he is 17: the chin is back (recessive), the cheeks are flat, the lips are flaccid, and the nose appears to stick out because the lower jaw is recessed.
Studies have been done with monkeys to show the effects of mouth-breathing on growth. When the noses of perfectly normal growing monkeys were plugged, their faces began to grow downward and backward rather than downward and forward
(Neuromuscular and Morphological Adaptations in Experimentally Induced Oral Respiration,” Nasorespiration Function and Craniofacial Growth).Mouth-breathers continue to have facial changes occur throughout life. Depending on the extent of the mouth-breathing, the chin may continue to become more recessive, bringing the soft tissue drape of the cheeks and nose downward. This can result in the cartilage of the nose being pulled down and back, making it appear as if there is a bump in the nose where the nasal bone is located.
Tilting the head in an unconscious effort to open the airway may mask some of the downward and backward change. This results in a forehead that slopes backward, but the chin does not appear as recessive.As both jaws fall farther back, the airway becomes smaller. As the airway becomes smaller, there is a greater chance that the person will have OSA (obstructive sleep apnea) – especially as he or she grows older, loses muscle tone, and perhaps gains weight.
Mouth-breathing also contributes to an unstable orthodontic result because the forces of the tongue and cheeks are unbalanced (see Proper Oral Posture).