Definitions, Epidemiology, and Etiology of Sleep Bruxism
Sleep bruxism (SB) is a common sleep-related movement disorder that is represented by clenching or grinding of the jaws of teeth. Bruxism may also occur during wakefulness and is then primarily characterized by clenching or tapping of the teeth or jaw bracing without tooth contact
Sleep bruxism is not always a harmless condition. It can have harmful effects on ranging from:
- Dental problems – tooth wear, fractured teeth, failures of dental restoration or implants
- Musculoskeletal problems – hypertrophied masticatory muscles, temporomandibular pain and headache
When any of these possible consequences is present, treatment of SB may be indicated1. Management of SB includes sleep hygiene instructions, occlusal stabilization appliances, and obstructive sleep apnea treatment.
Sleep bruxism is motor activity that has drawn increasing interest dentistry in recent years. Although SB is not a life-threatening disorder, it can affect the patient’s quality of life
Self-reports of jaw clenching and tooth grinding are helpful to assess the presence of absence of SB. Questionnaires can be easily used at medical/dental appointments. The main advantages of questionnaires are their ability to gather subjective information efficiently over large populations with limited cost involvement.
Nonetheless, questionnaires have some limitations. SB-related signs, symptoms and awareness of bruxism vary over time. Thus, an overestimation or underestimation of the prevalence of SB via questionnaires has been reported. Plus, a large percentage of patients are unable to identify themselves as bruxers, especially those individuals who sleep alone. Descriptions of tooth grinding are usually associated with the sleep partner’s grievance of disturbing grinding noise. Nevertheless, questionnaires can at least guide the clinician in the diagnosis process.
Example of questionnaire
- Has anyone said you grind your teeth at night?
- Do you very often, often, occasionally, or never grind your teeth during sleep?
- Do your teeth, gums, or jaw muscle feel sore when you wake up?
- Is your jaw ever fatigued or sore on awakening in the morning?
- Do you ever experience temporal headaches on awakening in the morning?
- Are your teeth or gums ever sore on awakening in the morning?
Presently, a clinical diagnosis of SB is based on report of tooth grinding sounds by the sleep partner and presence of tooth wear, tooth mobility, and damage to teeth / dental restorations. Other clinical symptoms can include jaw muscle pain, dysfunction in the temporomandibular joint, and fatigue or stiffness of jaw joint on waking. Also, additional clues to SB include masticatory muscle hypertrophy or tongue and cheek indentation. Because these subjective symptoms or signs such as are secondary, they should not be used as primary confirmation of clinical SB.
Because of its inconsistency over time, SB is difficult to diagnosis. Some helpful diagnostic benchmarks have been proposed by the American Academy of Sleep Medicine. The patient reports or is aware of tooth grinding sounds or tooth clenching during sleep.
One or more of the following signs is present:
- Abnormal wear of the teeth.
- Discomfort, fatigue, or pain of the jaw muscles and locking of the jaws on awakening.
- Hypertrophy of the masseter muscles on voluntary forceful clenching.
- Jaw muscle activity cannot be better explained by another current sleep disorder, medical or neurologic disorder, medication use, or substance use disorder.
Excessive tooth wear, an indirect indicator of SB, is the most common obvious clinical sign of the presence of SB. However, the clinician should keep in mind that tooth wear may have occurred months or years before the examination. Tooth wear is an aggregate consequence of both functional and parafunctional wear. It does not show ongoing or current bruxism activity. Also, tooth wear does not indicate whether the subject has static tooth clenching. Plus, a number of factors, including age, gender, diet, occlusal condition (eg, subject biting on only a few teeth because of a malocclusion), amount and type of fluid intake, oral dryness resulting from medications or health conditions (gastroesophageal reflux, anxiety), and tooth density (wear resistance) are all related to various degrees of tooth wear.
An assortment of signs and symptoms related to Sleep Bruxism in conjunction with complaints by a sleep partner is the most efficient and reasonable way to assess Sleep Bruxism.
1. Lobbezoo F, Blanchet P, Lavigne GJ. Management of movement disorders related to orofacial pain: Principles and practice. In: Sessle BJ, Lavigne GJ, Lund JP, Dubner R (eds). Orofacial Pain and Related Conditions, ed 2. Chicago: Quintessence, 2008: 211-217