Mouth Breathing: What Can Go Wrong?

Ms. Trisha O'Hehir, MS, RDH

Several things can go wrong with mouth breathing, leading to a cascade of health problems. The most obvious are dry mouth and lack of nasal filtration. Dryness leads to enlarged and inflamed tonsils and adenoids and an increased risk of upper respiratory tract infections. Dryness in the mouth and throat also leads to the collapse of the throat and the tongue falling into the throat which can both lead to obstructive sleep apnea.

Mouth breathing bypasses the nitric oxide advantage. Nitric oxide is released in the nasal cavity and inhaled into the lungs with nose breathing. Nitric oxide increases the efficiency of oxygen exchange, leading to as much as 18 percent more oxygen being absorbed. With less oxygen being delivered to the brain, muscles and all the cells of the body, the body does not function optimally. Sleep is often disturbed and of poor quality, leaving the mouth breather tired in the morning and feeling fatigued mid-afternoon. All signs of sleep deprivation.

Attention deficit hyperactivity disorder (ADHD) is also linked to mouth breathing, as the symptoms of sleep deprivation and ADHD are similar. With less oxygen absorbed and less reaching the brain, mouth breathers rarely achieve regenerative sleep. Despite many hours of sleep, they wake sleep deprived. Regenerative sleep is needed for the release of human growth hormone, necessary in children for bone and muscle growth. Without this, children may fail to thrive.

Mouth breathing changes the tongue rest position. Normal palatal growth is directed by the tongue’s gentle pressure against the palate during swallowing. Humans swallow at a minimum of 500 times each day, providing pressure, and stimulating DNA and stem cells located in the palatal suture and within the periodontal ligaments around the teeth. When the tongue rests in the palate, the teeth erupt around the tongue, producing a healthy arch form. The lateral pressure from the tongue counters inward forces from the buccinator muscles. When the tongue is down and forward, the buccinator muscles continue to push inward unopposed, causing the upper arch to narrow. Anterior growth is also slowed, and the sinuses do not reach their full growth potential. Children who mouth breathe have an underdeveloped, narrow maxilla with a high vault. They develop a retrognathic mandible and generally have a long face.

Dr. Harold, an orthodontist, observed that most of his patients with crowded teeth were also mouth breathers. He designed a research study to test his theory. He surgically blocked the noses of monkeys with silicone plugs and implanted plastic blocks on the palates to force the tongue down and forward. The test monkeys all developed malocclusions from mouth breathing. Mouth-breathing-related problems of skeletal development will set children up for obstructive sleep apnea later in life.

It might seem logical that mouth breathing occurs because the nose is congested, but that is not always the case. There are two respiratory centers in the brain. One distinguishes between nose and mouth breathing and the other monitors carbon dioxide levels. Mouth breathers exhale carbon dioxide too quickly, and the respiratory center in the brain stimulates the goblet cells to produce mucous in the nose to slow breathing. This creates a cycle of mouth breathing triggering mucous formation, and nasal passage blocking, leading to more mouth breathing. Ironically, mouth breathing can cause nasal congestion leading to more mouth breathing.

In some cases, mouth breathing is caused by ankyloglossia, or a tight lingual frenum keeping the tongue from effectively moving in the mouth to assist in chewing and swallowing and comfortably resting on the palate. Unless a frenectomy is done, mouth breathing will continue. Ankyloglossia can be diagnosed and treated in the first few days after birth. However, many cases are ignored until significant problems have developed. Early intervention can prevent subsequent problems.

These are just a few of the many problems associated with mouth breathing. Clinicians have an opportunity to check all patients, young and old to determine those who are mouth breathing.

Correcting mouth breathing and tongue positioning in children will prevent a cascade of problems both during childhood and growing into adults. The problems adults have because of mouth breathing can also be addressed, leading to better breathing, better sleep and a better life.

Ms. Trisha O'Hehir, MS, RDH together with UK-based RDH Timothy Ives recently authored the book LipZip, featuring stories of mouth breathers switching back to nose breathing and the impact it has on their lives. The book is available at www.lipzipbook.com.