Teeth grinding (bruxism) facts you didn’t know before

Teeth grinding (also known as bruxism) describes the repetitive jaw-muscle activity often characterized by teeth clenching, teeth grinding, jaw bracing, or jaw thrusting — so 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 are 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, grind or clench their teeth to some degree.

Paleoanthropological investigations have found evidence of teeth grinding in our ancestors. It is thought that teeth grinding may have been evolutionary advantageous in helping to keep our teeth sharp.

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 our bodies’ reflex to help open up the airways so they can resume breathing.

This is why, in recent years, experts have begun to view bruxism as a normal behavior instead of a disorder. Especially since most people will brux at some point in their lives. That is: bruxism does not always require treatment. Management or intervention is needed only if the bruxism behavior causes other health problems. Examples of negative side effects of teeth grinding are premature wear to your teeth, jaw pain, and headaches.

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, their 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 10x stronger than our regular food chewing actions. Duration also matters as some bruxers grind their teeth for hours every night when we normally only spend 30-40 minutes a day chewing our food.

But beyond tooth wear, these excessive forces could also cause loose teeth or filling, as well as fractures or damages to your expensive dental implants.

Bruxism could also lead to tenderness or pain in your jaw muscles, headaches, and sometimes, tinnitus. These symptoms are similar to temporomandibular joint disorder (TMD). Though the research is still unclear on the exact relationships 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 keep getting 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 (previously called “nocturnal bruxism”) and awake bruxism (previously called “day bruxism”). Although they share similar characteristics and symptoms, they are considered two different conditions 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) subconsciously 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 are mostly one or the other.

Furthermore, bruxism can also be categorized into primary or secondary. Secondary bruxism refers to bruxism that is caused by another condition or external factors (e.g. sleep apnea, neurological disorder, adverse effect of some drugs). Whereas primary bruxism is idiopathic, or does not have an apparent cause.

Someone who suffers from Obstructive Sleep Apnea (OSA) is a common example of secondary sleep bruxism. Bruxism is more common in OSA patients and some patients have experienced significant improvement in their bruxism after addressing their OSA with CPAP machines.

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 can happen 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 PSG 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 a current grinder 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 and years before the check-up and that you’re currently no longer grinding your teeth.

This is where diagnosis of sleep bruxism should be accompanied by other symptoms besides just tooth wear. Studies found that 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 causes sleep bruxism

While there is a strong connection between one’s self-perception of stress and Awake Bruxism (grinding/clenching during the day), there is no conclusive scientific evidence that stress and/or anxious personality cause teeth grinding in sleep.

However, stress may have an indirect impact on sleep bruxism as one’s stress level could alter the brain’s neurochemistry and sleep pattern (more frequent microarousals), which in turn affect bruxism. So while having a high-stress level can worsen your bruxism, don’t count on curing your bruxism by reducing your stress level 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, science has not supported this theory. In fact, researchers found that bruxism is equally common in those with perfect bites as in those with imperfect bite, making that theory unlikely.

Now researchers know that the cause of sleep bruxism lies in the central nervous system. It seems that there are groups of motor neurons in the brain stem (collectively termed the Central Pattern Generator) that are responsible for initiating sleep bruxism episodes. Unfortunately, we still don’t know what exactly causes this Central Pattern Generator to initiate the chewing movement. Scientists have started to find a few factors that seem to influence it. For example, changes in sleep pattern, level of microarousal during sleep, as well as several pharmaceutical agents that affect your nervous systems, like anti-depressants, hypnotics, and anxiolytics.

7. Mouth guard does not “treat” sleep bruxism

The most commonly prescribed solution for teeth grinding in sleep is mouth guards. It works as teeth protectors but does not stop or cure sleep bruxism. Many bruxers already know this as they can still see grinding or chewing marks on their worn-down mouth guards.

In the case of sleep bruxism caused by sleep apnea, there is a type of mouth guard called “Mandibular Advancement Device” that helps prevent airway collapse and has been shown to reduce OSA as well as bruxism activities. However, for other types of bruxism, a mouth guard is unlikely to do anything more than cover the teeth as it does not affect the central nervous pathway responsible for sleep bruxism.

Researchers are now looking into other approaches that can reduce (not eliminate) the bruxism activities to reduce their burden on the person’s dental & TMJ health. Botox, transcranial magnetic stimulation, and various forms of biofeedback devices are some of the new approaches that are currently being investigated.

Did these facts surprise you? What other facts about bruxism that you think we should cover in our next article? Tell us what you think in the comment section below.


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