High-risk obstructive sleep apnea and sleep/awake bruxism: How do they relate to TMD?
Editor’s note: During the 2015 annual meeting of the American Academy of Dental Sleep Medicine, dentists gathered from across the world to review and present clinical research in the field of dental sleep medicine. This year, like last, DentistryIQ is pleased to share blog posts from some of the AADSM Clinical Research Award winners, including students, which detail the noteworthy findings about their new research. Here, Elizabeth Kornegay, RDH, BSDH, focuses on the connection between sleep apnea and bruxism as they relate to predicting first-onset temporomandibular disorders.
Temporomandibular disorder (TMD) is a musculoskeletal disorder characterized by persistent pain in the temporomandibular joint, periauricular region, and/or the head and neck muscles. Obstructive sleep apnea (OSA) is a sleep-related breathing disorder characterized by repetitive collapse of the airway during sleep. Published evidence from our group showed that elevated risk for OSA predicts the first occurrence of TMD in initially pain-free individuals; (1) however, the mechanism underlying this finding is unknown. One hypothetical mechanism is that OSA is associated with increased parafunctional activity, such as sleep bruxism or awake bruxism, which contributes to the initiation of TMD in susceptible individuals. Bruxism is a repetitive jaw-muscle activity characterized by clenching or grinding of the teeth and/or bracing or thrusting of the mandible. It can occur during sleep (sleep bruxism) or during wakefulness (awake bruxism).
In up to 5.2 years of follow-up, participants completed TMD screening questionnaires every three months to monitor symptoms of first-onset TMD. Clinical re-examination determined TMD in the presence of: (1) ≥5 days per month of pain in the masticatory structures and (2) findings of arthralgia and/or myalgia. Risk for OSA, sleep, and awake bruxism were modeled in multivariable Cox proportional hazards regression to estimate hazard ratios (HR) and 95% confidence limits (CL) for incident TMD, adjusting for potential confounding.
Of a cohort of 2,660 adults, at baseline 5.8% of participants had elevated risk for OSA, 16.6% reported sleep bruxism at least one to three nights per month, and 14.7% reported awake bruxism at least some of the time. Over a median of 2.8 years, 252 of the adults developed first-onset TMD. In univariate analysis, elevated risk for OSA, sleep bruxism, and awake bruxism were each significant individual predictors of TMD incidence. In multivariable analysis, the strength of association between OSA risk and TMD incidence was not attenuated with subsequent inclusion of sleep bruxism and awake bruxism.
Our study found that symptoms of OSA, reports of awake bruxism, and reports of sleep bruxism all have a significant effect in predicting first-onset TMD. There was no evidence that the mechanism driving the relationship of OSA and first-onset TMD is due to either awake bruxism or sleep bruxism. Additionally, awake bruxism had a stronger association with OSA symptoms than sleep bruxism.
Elizabeth Kornegay, RDH, BSDH, graduated with a bachelor’s in dental hygiene from the University of North Carolina (UNC) at Chapel Hill School of Dentistry in May 2014 and is currently a Master of Science candidate in dental hygiene education at UNC. Kornegay is also a practicing dental hygienist and research examiner at the General and Oral Health (GO Health) Research Center at UNC. She is an active member of the American Academy of Dental Sleep Medicine (AADSM) and recently won the AADSM Graduate Student Excellence Award for “Elevated Risk for Obstructive Sleep Apnea Predicts Temporomandibular Disorder Independently of Sleep Bruxism and Awake Bruxism.”
