This content was created by Dr. Glenn Clark as part of his Systems Physiology, Sleep, Motor Disorders Course for Dental Residents of the Orofacial Pain and Oral Medicine master’s program at the Herman Ostrow School of Dentistry of USC.
Why is sleep a concern for dentists?
Dentists have always been interested in sleep because of bruxism, or the grinding of teeth, which sometimes is a powerful destructive motor event occurring during sleep. The field of sleep disorders is a relatively new field and with new scientific discoveries, we understand better the critical role the tongue and the jaw play in causing and preventing sleep disordered breathing.
The graph below shows growth of the number of citations in Medline in the topic of bruxism (which is not growing) and Obstructive Sleep Apnea which exhibits rapid, maybe even exponential growth.
The disorders of sleep are multiple and they have been categorized by The International Classification of Sleep Disorders (ICD-9-CM). The various disorders which are cataloged by this system are presented below. In 2005, an update of this classification was published.
If you are wondering why you should review this list of diseases, it is necessary to know a little about these other problems if patients with a possible Sleep-Breathing Disorder.
The main focus of these articles is Obstructive Sleep Apnea, snoring disorders, distinguishing between OSA snoring and primary snoring, and the discussions of diagnosis, mechanism, and treatment will be generally restricted to these two conditions.
Sleep Disordered Breathing & Dentistry
Dr. Robin is famous for describing children born with a mandibular growth insufficiency and which was named after him: Pierre Robin Syndrome (PRS) or Pierre Robin Sequence.
Dr. Robin also coined the term Glossoptosis, which means the abnormal downward or back placement of the tongue. His first article on this was published in 1923.
Picture Source: Gangopadhyay, N., Mendonca, D. A.; Woo, A. S. (2012). Pierre robin sequence. Seminars in plastic surgery, 26(2), 76–82. doi:10.1055/s-0032-1320065
Why do people wake up in the middle of the night?
Many reasons exist for this including urination urges, loss of slow-wave sleep as we age, the natural cycling of sleep from deep to shallow and back again, anxiety and worries that creep into our subconsciousness during sleep.
One interesting fact about sleep is that as we age, we sleep less, “From midlife until the eighth decade, total sleep time decreased, on average, by 27 minutes per decade.” What is evident is that by about 60, we sleep on average only 5 hours.
Classification for Sleep Disorders and Sleep Disordered Breathing
The International Classification of Sleep Disorders has published a list of sleep disorders and it has been updated several times since it was first published in 1990 (i.e. 1990, 1997, 2001, 2005).
ICSD-2 Sleep Disorder Categories
- Sleep-related breathing disorders
- Hypersomnias of central origin
- Circadian rhythm sleep disorders
- Sleep-related movement disorders
- Isolated symptoms, apparently normal variants and unresolved issues
- Other sleep disorders
Sleep-Related Breathing Disorders
|Sleep-Related Breathing Disorders||(ICD-9)||(ICD-10)|
|Obstructive sleep apnea, adult||327.23||G47.33|
|Obstructive sleep apnea, pediatric||327.23||G47.33|
|Sleep apnea/sleep related breathing disorder, unspecified||320.2||G47.30|
|Restless legs syndrome||333.49||G25.81|
|Periodic limb movement disorder||327.51||G47.61|
|Sleep-related leg cramps||327.52||G47.62|
|Sleep-related rhythmic movement disorder||327.59||G47.69|
|Sleep-related movement disorder (NOS)||327.59||G47.90|
|Sleep-related movement disorder due to drug or substance||327.59||G47.67|
|Sleep-related movement disorder due to medical condition||327.59||G47.67|
Circadian Rhythm Sleep Disorders
Circadian Rhythm Sleep Disorders are related to the timing of sleep within the 24-hour day. Some of these disorders are influenced by the timing of the sleep period that is under the individual’s control (e.g., shift work or time-zone change), whereas others are disorders of neurologic mechanisms (e.g., irregular sleep-wake pattern and advanced sleep-phase syndrome). Some of these disorders can be present in both an intrinsic and extrinsic form; however, their common linkage through chronobiologic, pathophysiologic mechanisms
dictates their recognition as a homogeneous group of disorders.
What are parasomnias?
The parasomnias are disorders of arousal, partial arousal, and sleep-stage transition. While there are many causes of involuntary motor activity in the jaw, if they occur during sleep they are called parasomnias. Parasomnias include talking, repeated jaw motions such as chewing or grinding and occasional a rapid closure of the jaw.
The snapping shut motion of the jaw or repeated twitching of the palate is called a myoclonus. The definition of myoclonus is a sudden, brief, shock-like, involuntary movements caused by muscular contractions. Myoclonus therapy is limited and usually involves symptomatic treatment with valproic acid or clonazepam.
4 Types of Parasomnias
Parasomnias are problems that intrude into the sleep process and are not primarily disorders of sleep or wake states These disorders are manifestations of central nervous system activation, usually transmitted through skeletal muscle or the autonomic nervous system. They are divided into 4 groups: arousal disorders, sleep-wake transition disorders, parasomnias usually associated with rapid eye movement (REM) sleep, and other parasomnias.
1. Arousal Disorders
Arousal disorders are manifestations of partial arousal that occur during sleep. These disorders are the “classic” arousal disorders that appear to be primarily disorders of normal arousal mechanisms.
2. Sleep-Wake Transition Disorders
Sleep-wake transition disorders are those that occur mainly during the transition from wakefulness to sleep or from one sleep stage to another. Although under some circumstances these disorders can occur within specific sleep stages, this is usually the exception rather than the rule.
3. Parasomnias Associated with REM Sleep
The parasomnias usually associated with REM sleep have their onset during the REM sleep stage; some of these REM sleep parasomnias do occur during other sleep stages, but this occurrence is rare.
4. Other Parasomnias
Other parasomnias are those parasomnias that do not fall into the categories of arousal disorders, sleep-wake transition disorders, or parasomnias associated with REM sleep.
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