Medically reviewed by Brittany Ferri, PhD
Teeth grinding facts
Teeth grinding (also known as bruxism) describes the repetitive jaw muscle activity often characterized by teeth clenching, teeth grinding, jaw bracing, or jaw thrusting — which is so much more than just teeth grinding. There are already many articles out there talking about what bruxism is and what you can do about it. But very few mention the following facts about teeth grinding that we think you should know…
1. Not all teeth grinding is bad
Before you let the definition of teeth grinding or teeth clenching scare you, it’s worth mentioning that bruxism is actually quite common. 85 to 90% of the population will, at some time in their lives, grind or clench their teeth to some degree.
More recently, researchers also found that this chewing-like activity during sleep may not be so pointless after all. In patients with sleep apnea, for example, bruxism appears to be the bodies’ reflex to help open the airways so they can resume breathing.
This is why, in recent years, experts have begun to view bruxism as a behavior instead of a disorder. That is – in otherwise healthy individuals, bruxism does not require treatment. Management or intervention is needed only if bruxism behavior causes significant health concerns or is driven by an underlying medical disorder (for example, sleep apnea).
So if you think you grind your teeth, either because someone has heard you grinding in your sleep or if your dentist mentioned it, don’t immediately jump to the conclusion that it’s something you have to “fix” or eliminate. For some, bruxism might be so mild that it requires no intervention.
For example, if you grind your teeth occasionally and experience no painful symptoms or dental issues, your bruxism might be mild enough that you don’t have to do anything about it.
2. Side effects of teeth grinding go beyond your teeth
The most obvious consequence of bruxism is that it wears down your teeth enamel. This logically makes sense as the force involved during bruxism episodes can be up to 10 times stronger than our regular food chewing actions. Duration also matters as some bruxers grind their teeth for hours every night, which is surely more frequent than spending 30 to 40 minutes each day chewing food.
But beyond tooth wear, these excessive forces could also cause loose teeth or fillings, as well as fractures or damages to expensive dental implants.
Bruxism could also lead to tenderness or pain in your jaw muscles, headaches, and sometimes, tinnitus. These symptoms are similar to those of temporomandibular joint disorder (TMD). However ,the research is still unclear on the exact relationship between TMD and bruxism.
Not all bruxers will experience these painful muscular and joint symptoms since there are considerable individual differences in the intensity of muscular activity during bruxism episodes and individual pain tolerance. There are many cases of bruxers who show extreme degrees of tooth wear without any pain or tenderness in their jaw muscles.
Finally, while not necessarily a health issue, bruxism may cause relationship problems if the bed partners of bruxers are continually wakened by the loud teeth grinding noises.
3. There are different types of bruxism. Which type are you?
There are two main types of bruxism: sleep bruxism and awake bruxism. Although they share similar characteristics and symptoms, they are considered two different concerns with very different causes.
“Clenching” or “bracing” of the jaw (with no sound) while awake are characteristics of awake bruxism. On the other hand, sleep bruxers grind (or clench) unconsciously in their sleep. These movements are often accompanied by loud involuntary grinding or clicking noises.
Stress is almost always related to awake bruxism, while it is not related to sleep bruxism. It’s possible for someone to have both awake and sleep bruxism, although people usually only have one or the other.
Furthermore, bruxism can also be categorized into primary or secondary bruxism. Secondary bruxism refers to bruxism that is caused by another condition or external factors (e.g. sleep apnea, neurological disorder, or an adverse effect of some drugs). Whereas primary bruxism is idiopathic, or does not have an apparent cause.
Bruxism is more common in those who have Obstructive Sleep Apnea (OSA) and some patients have experienced significant improvement in their bruxism after addressing their OSA with CPAP machines, which is the gold-standard treatment for OSA.
Lastly, individuals tend to vary in their bruxism activities. Some people grind more than clench, while others only clench and brace their teeth. In bruxism studies, these subgroups are frequently noticed, but researchers are still investigating this area.
It’s important to understand which type of bruxism you have because it can influence the course of action you can take to address your bruxism. For example, management of awake bruxism would be very different from sleep bruxism as awake bruxism can be effectively addressed with behavioral and psychological approaches whereas the same approach will not work for sleep bruxism.
4. Tooth wear may have happened a long time ago
A definite sleep bruxism diagnosis requires a sleep study in the sleep lab using polysomnography (PSG) with audio + video recording. This method is quite expensive and requires highly trained professionals to score and interpret the data.
Because this accurate diagnostic tool is not broadly available to the public, most bruxers find out about their night-time grinding habit from their dentist, who might have noticed tooth wear during their regular dental check up. This often prompts bruxers to seek solutions like a mouth guard.
Unfortunately, tooth wear is not always a reliable indicator that a person is due to current grinding behavior because of two things. One, the wear on your teeth might have been caused by other factors, like acidic diet or GERD (acid reflux). Second, unless your dentist has been regularly and systematically monitoring your teeth, the tooth wear could have occurred months or years before that visit and you may not even be still grinding your teeth.
This is where diagnosis of sleep bruxism should be accompanied by other symptoms besides just tooth wear. Studies found that recent reports of bruxism activities from a bed partner or a family member or others who sleep in the same room can help elucidate someone’s current bruxism status. They might hear the loud grinding, crunching noise or might have seen the person making chewing movements in their sleep. Of course, if you live alone or have a partner who is a heavy sleeper, then you might want to try recording yourself or using an app to see if you are still actively grinding your teeth at night.
5. There’s no conclusive evidence that stress directly causes sleep bruxism
While there is a strong connection between one’s perception of stress and awake bruxism (clenching during the day), there is no conclusive scientific evidence that stress and/or an anxious personality directly cause teeth grinding in sleep.
However, stress may have an indirect impact on sleep bruxism as one’s stress levels could alter the brain’s neurochemistry and sleep patterns (leading to more frequent awakenings), which in turn can increase bruxism activities. So while high stress levels can worsen your bruxism, don’t count on curing your bruxism by reducing your stress levels to zero.
6. Bruxism starts in the brain stem, not your teeth
There was once a widespread belief that imperfect bite caused bruxism and that fixing the bite (sometimes through jaw surgery) could eliminate bruxism. However, research has not supported this theory. In fact, experts have found that bruxism is equally common in those with perfect bites as it is in those with imperfect bites, making that theory unlikely.
Now researchers know that the cause of sleep bruxism is linked to sleep-related disruptions (micro-awakenings) which are influenced by a myriad of neurochemicals, genetics, and lifestyle factors.
7. Mouthguards do not “treat” sleep bruxism
The most commonly prescribed solution for teeth grinding in sleep is mouthguards. These work as teeth protectors, but do not stop or cure sleep bruxism. Many bruxers already know this as, they can still see grinding or chewing marks on their worn-down mouthguards.
In the case of sleep bruxism caused by sleep apnea, there is a type of mouthguard called a “Mandibular Advancement Device,” which helps prevent airway collapse and has been shown to reduce OSA as well as bruxism activities. However, for other types of bruxism, a mouthguard is unlikely to do anything more than cover the teeth, as it does not affect the sleep disruptions linked to sleep bruxism.
Sources
- Lobbezoo F, Ahlberg J, Raphael KG, Wetselaar P, Glaros AG, Kato T, Santiago V, Winocur E, De Laat A, De Leeuw R, Koyano K, Lavigne GJ, Svensson P, Manfredini D. International consensus on the assessment of bruxism: Report of a work in progress. J Oral Rehabil. 2018 Nov;45(11):837-844.
- Castrillon EE, Ou KL, Wang K, Zhang J, Zhou X, Svensson P. Sleep bruxism: an updated review of an old problem. Acta Odontol Scand. 2016 Jul;74(5):328-34.
- Lavigne GJ, Rompré PH, Poirier G, Huard H, Kato T, Montplaisir JY. Rhythmic masticatory muscle activity during sleep in humans. J Dent Res. 2001 Feb;80(2):443-8.
- Bader G, Lavigne G. Sleep bruxism; an overview of an oromandibular sleep movement disorder. REVIEW ARTICLE. Sleep Med Rev. 2000 Feb;4(1):27-43.
- Raphael KG, Santiago V, Lobbezoo F. Is bruxism a disorder or a behaviour? Rethinking the international consensus on defining and grading of bruxism. J Oral Rehabil. 2016 Oct;43(10):791-8.
