Teeth grinding linked to apnoea

There is a high prevalence of nocturnal teeth grinding, or bruxism, in patients with obstructive sleep apnoea (OSA), particularly in Caucasians. New research presented at Chest 2009, the 75th annual international scientific assembly of the American College of Chest Physicians (ACCP), found that nearly one in four patients with OSA suffers from night time teeth grinding; this seems to be especially more prevalent in men and in Caucasians compared with other ethnic groups.

It is estimated that 8% of the general US population suffers from bruxism, a condition frequently associated with a pre-existing dental or jaw disorders, as well as stress.

"The relationship between obstructive sleep apnoea and sleep bruxism is usually related to an arousal response. The ending of an apneic event may be accompanied by a number of mouth phenomena, such as snoring, gasps, mumbles, and teeth grinding," said Shyam Subramanian, MD, FCCP, Baylor College of Medicine, Houston, TX.

"Men typically have more severe sleep apnoea, and perhaps may have more arousal responses, which may explain the higher prevalence of teeth grinding in men. Besides, men characteristically tend to report more symptoms of sleep apnoea than women, such as snoring, loud grunting, and witnessed apnoeas."

Anxiety and caffeine lead to grinding
Other factors that might help explain the relationship between sleep apnoea and teeth grinding include anxiety and caffeine use.

"High levels of anxiety can lead to bruxism, and untreated sleep apnoea is known to cause mood disturbances including depression and anxiety," said Subramanian. "Daytime sleepiness from sleep apnoea may cause a person to ingest caffeine, and this has also been associated with a high risk of bruxism."

Through a retrospective chart review, Subramanian and his colleagues, from the Baylor College of Medicine, Houston, TX, assessed the prevalence of bruxism and gastro-oesophageal reflux (GERD) in 150 men and 150 women with OSA. Each group consisted of 50 Caucasians, 50 African-Americans, and 50 Hispanics. Results showed that 25.6% of patients suffered from teeth grinding, while 35% of all patients with OSA complained of nocturnal heartburn and GERD symptoms.

The researchers also examined the influence of gender and ethnicity on OSA, GERD, and bruxism. They found that bruxism was higher in men than in women—43% vs. 31%. Caucasians had the highest rate of bruxism compared to other ethnic groups—35% vs. 19% in Hispanics. African-Americans have the highest prevalence of GERD—40% vs. 31% in the Hispanic population and 34% in Caucasians. Overall, no correlation was observed between the presence of self-reported GERD and bruxism.

Untreated bruxism can lead to excessive tooth wear and decay, periodontal tissue damage, jaw pain, and temporomandibular joint or TMJ pain, headaches, and sleep disturbances for patients and their bed partners.

Some therapies do help
"Bruxism can be both a daytime syndrome as well as a night time syndrome, but it is bruxism during sleep, including short naps, that causes the majority of health issues," said Subramanian.

"Studies do suggest that when sleep bruxism is related to OSA, certain therapies, including continuous positive airway pressure, may eliminate bruxism during sleep."

"Sleep disorders such as sleep apnoea can lead to many secondary health conditions," said Kalpalatha Guntupalli, MD, FCCP, President of the American College of Chest Physicians.

"When treating sleep apnoea, clinicians must also recognize and address secondary health conditions, such as bruxism, in order to fully manage a patient's sleep disorder." – (EurekAlert, November 2009)

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