USC University of Southern California

Herman Ostrow School of Dentistry of USC

Helping Patients Breathe Easier and Sleep Better

Many patients might be surprised to find out that their dentist cares about how well they have been sleeping. Besides helping their patients with harmful nighttime dental habits such as jaw clenching and teeth grinding, they can also play a role in helping them address potentially serious breathing problems.

Sleep apnea is characterized by pauses in breathing longer than 10 seconds as an individual sleeps. The resulting periodic lack of oxygen in the blood can have far-reaching detrimental affects throughout the body, said Glenn Clark, director of the Orofacial Pain and Oral Medicine Program with the USC School of Dentistry.

“Periodic hypoxia [low oxygen levels] can bring about serious cardiovascular and central nervous system complications,” he said.

In a literature review article published in May’s Journal of the American Dental Association, Clark and School of Dentistry clinical associate professor Michael Simmons pointed out how episodic hypoxia has been linked to cellular damage in the brain – damage that may not be reversible – and cognitive changes in both laboratory animals and humans. Studies suggest that sleep-disordered breathing, such as sleep apnea, may have negative affects on learning and memory functions, Clark said.

The cardiovascular implications of sleep apnea are also worrisome, he added. During periods of hypoxia, hemoglobin – the molecule that normally binds to oxygen in the blood – instead takes oxygen from the cell walls along the interior of blood vessels. This changes the properties of the vessels in such a way that allows plaque to bind more easily, potentially leading to atherosclerosis and other serious cardiovascular problems, Clark said.

“A 40-year-old patient with sleep apnea can have the arteries of a 60-year-old,” he said.

The risk of sleep apnea increases greatly according to age and body mass index and is much more common in men, said Reyes Enciso, assistant professor of clinical dentistry at USC.

“As many as one out of every six people over 50 has at least mild sleep apnea,” she said, “and it’s estimated that almost 75 percent of severe apnea cases are undiagnosed.”

The majority of sleep apnea cases involve obstruction of the airway, whether the tongue or soft palate blocks the airway or the surrounding muscles relax and allow the airway to momentarily collapse. Clark and Enciso both encourage patients to talk about their sleep habits with a dentist or doctor, including


instances of daytime sleepiness and snoring – loud snoring with telltale pauses is an indicator of sleep apnea as it is audible evidence of the tongue or soft palate obstructing the airway, Enciso mentioned.

After risk factors are identified, patients are referred for a polysomnogram, or “sleep study,” during which a patient’s vital signs and behaviors are closely monitored as they sleep. After a patient is diagnosed, customary treatment for sleep apnea can involve using a continuous positive airway pressure (CPAP) device with a mask that keeps air flowing into the nose during sleep. But patients with mild cases of sleep apnea may also find effective relief by using a dental appliance that draws the lower jaw forward and keeps the tongue from blocking the airway, Clark added.

Along with having conversations with patients about their sleep, dentists also have the opportunity to spot potential anatomical problems with the patient’s airway; computerized tomography (CT) scans used to plan oral surgeries and other procedures can reveal risk factors for obstructive sleep apnea, Enciso said.

Clark and Enciso hope to eventually use cone-beam CT scans in conjunction with clinical research data in order to better identify patients who may be at risk for sleep apnea in future.

“The airway changes with weight gain and age,” Clark said, detailing how progressively drooping soft tissues can block the airway and how weakened muscles plus the presence of nearby fat deposits can cause the airway to collapse more easily.

The goal is to eventually be able to take a CT scan of a patient and artificially add weight or age to the three-dimensional scan to see how the airway’s anatomy could change. Such data could help predict whether a patient might be at risk for sleep apnea in the future and would encourage them to start preventive measures, Enciso said.

“We want to be able to find individuals at risk for sleep apnea as early as possible,” she said.


Above:   Dr. Reyes Enciso