It is an unconscious habit that probably only somebody you sleep beside will identify. Or maybe your dentist. But excessive teeth grinding and clenching can have unexpected, painful consequences.
Grinding/clenching, clinically known as bruxism, is common, periodic behaviour in children and adults, but it is the latter who are more likely to have problematic symptoms, depending on the frequency of the habit. The signs are not always just the obvious ones of worn teeth.
The causes are believed to be varied but there is a strong association with stress and anxiety. No surprise, then, that a year after the start of the Covid pandemic, there was research reporting “intensification” of the problem among patients in Poland and Israel. Irish dentists too were, anecdotally at least, seeing more cases then – a trend that seems to have continued, in parallel with studies that consistently suggest a societal rise in anxiety.
It is hard to say whether bruxism is on the increase or just being identified more, says Dr Gillian Smith, a dentist working in orofacial pain management at the Fitzwilliam Clinic in Bray, Co Wicklow. She personally has not seen more patients showing the effects of teeth grinding/clenching but has heard professional colleagues talk about a rise in incidence.
South Dublin dentist Dr Sean Malone is one such colleague. He reports an increase in the past three years of people cracking their teeth, fillings and implants. “It is related to static clenching – a stress-related habit which is completely useless, ie it has no function in chewing food. If you think that you can easily crack a walnut with your back teeth, you can exert a huge amount of pressure when you clench.”
A typical scenario he sees in general practice in Sandycove is a patient who comes in with a cracked filling; then three months later with a broken tooth; then three months later with another broken tooth or a crown that has fallen out. “It is very difficult for the patient to see the pattern unless it is explained. It can be extremely disturbing for patients; they are almost traumatised. It can be very challenging for the dentist also.”
While sleep partners may hear grinding of teeth, patients often remain unaware of silent clenching. Grinding usually happens during the night, whereas clenching can be a daytime habit at times of intense effort or concentration, be that lifting weights in the gym or beavering away at a computer, or during episodes of stress and anxiety.
Another possible, indirect link to anxiety is bruxism being a well-documented side-effect of some anti-depressant medications
Self-awareness offers some chance during waking hours of altering what is involuntary behaviour. But during sleep it is about trying to minimise the negative effects with what dentists call a night-time stabilisation device – a mouthguard – and, meanwhile, tackling modifiable root causes such as stress with, say, relaxation techniques.
People habitually grinding/clenching may complain of unexplained pain in their jaws and face because the detrimental effects can go beyond the teeth. Bruxism can have a knock-on effect on jaw joints and muscles, causing what is called a temporomandibular disorder (TMD) and, in some cases, resulting in chronic headache. TMD is an umbrella term for more than 30 conditions that cause pain and dysfunction in the temporomandibular joint (TMJ), a hinge-like joint that connects the lower jaw to the skull, and in muscles that control jaw movement.
“We know there is a strong association between TMDs and headaches,” says Dr Smith. If you have genetic susceptibility to headaches, issues with jaw joints and muscles may drive on into headache pain. The head and neck area both feed into the same part of the nervous system. If your genes make you prone to headaches, you are more likely to suffer them as a result of toothache or upper respiratory tract infections than people without that genetic predisposition, she says. “If your clenching and grinding is significant, it’s not that it causes the headache, but it can switch on the headache activity.”
At the Bray clinic they see a lot of patients suffering both TMD and headaches, which need to be treated as separate entities.
“If we only treat one, they don’t get better. Sometimes, depending on the severity of the secondary problem, you can treat one and the other improves. So, for example, if we have somebody with a slipped disc in their jaw joint, called a locked joint, and we treat the locked joint, the headache pain resolves; or sometimes we treat the headache pain, the jaw discomfort improves. But a lot of the time, we have to manage both. They have a symbiotic relationship.”
[ Taking stress out on your teeth? Get a mouthguardOpens in new window ]
While grinding and clenching are associated with stress, “there are a lot of possible factors and too many to isolate”, says Dr Smith. “We do know that people grind their teeth when they’re not stressed, and that’s probably genetically determined. We also know ... that we tend to rock or grind our teeth when we are in the lighter states of sleep.”
So perhaps the association with anxiety is due to the impact emotion has on sleep. “If we’re stressed, we don’t hit the deeper levels of sleep.”
Another possible, indirect link to anxiety is bruxism being a well-documented side effect of some antidepressant medications, and there has been a rise in these being prescribed in Ireland. There are also nonpharmacological stimulants, says Dr Smith. Cocaine use, for instance, is linked to quite intense teeth grinding.
She also points out that research indicating a rise in bruxism is based on self-reported grinding, which is different from actual tooth contacts. If participants reported that they felt like they were grinding, “how much in reality did they grind in their sleep? That’s a hard thing to measure.”
Once somebody is aware they have a problem with grinding or clenching, the first step is usually to acquire a customised mouthguard. “Botox does have some use for reducing the size and power of an overdeveloped muscle, but it will not stop the clenching or grinding activity,” says Dr Smith.
Physiotherapist Kim Cusack, who specialises in orofacial pain, brings another dimension to treatment of bruxism issues. While the obvious knock-on effect is tooth wear, “a staggering 65 per cent of those with temporomandibular disorder clench and grind”, she says. “Current international guidelines advocate physiotherapy as first-line treatment for temporomandibular disorder. Like any chronic pain condition, it is inherently influenced by biological factors, stress sensitivities and environmental interactions.” Multidisciplinary management is recommended for the best results.
Most patients attending Cusack’s clinic, Faces Physiotherapy in Dublin, have been referred by other health professionals, such as dentists, orofacial pain specialists and GPs. “This is ideal as 70 per cent of orofacial pain comes from the teeth/dental pulp and oral mucosa,” she says. “Having prior assessment and exclusion of dental sources of pain is important to ensure appropriate diagnosis and management.”
Anecdotally, anyone working in orofacial pain has noticed a huge increase in demand in recent years, she reports. This is attributed to increased awareness and access to information via social media, but also to a Covid effect on anxiety levels. “Stress certainly plays a part in increased oral behaviours, as well as [in] pain sensitivity and demand for orofacial pain services are at an all-time high.”
The people she sees have often tried things like mouthguards, medications and, increasingly, Botox. “If these haven’t been trialled my clients will often ask for more information about the risks and benefits of each.”
Pain is inherently biopsychosocial, says Cusack. “We no longer see people as ‘just the jaw’ but the person with the jaw pain. Appreciating the person as a whole, their past experiences, current challenges and worries about their pain is integral to appropriately managing their condition.” In many cases TMD can be improved easily with supported self-management strategies.
“In others it has a relationship with tension-type headache, migraine and other chronic overlapping pain conditions,” she says. “But there are plenty of things that can be done to improve symptoms and quality of life with the support of a good multidisciplinary team, with the patient at the forefront.”
Bruxism and stress: ‘It happens when I’m at my laptop, if it’s a tough day’
The first warning signs that Mark (32) was grinding his teeth excessively were spotted at a dental clinic about 10 years ago.
“I remember saying I don’t think I’m stressed, but they were saying you definitely have signs of grinding your teeth.” He started wearing a mouthguard at night, “and that kind of settled things down” – for a while. “I wasn’t good at using it every night and that’s when my problem definitely got worse. The muscles of my jaw just got so inflamed, like huge.”
It became quite painful, he says, and was causing headaches.
Once he learned this was linked to his teeth grinding, “that scared me back into using a mouthguard”. He was also referred to physiotherapist Kim Cusack, who specialises in orofacial pain.
She showed him how to do exercises and daily massages of muscles around the temporomandibular joint (TMJ) to counteract his tendency “to hold all my tension in my jaw”. He believes it is the physio that has made the biggest difference, as before that he would still sometimes have pain even though he was using the mouthguard.
For a 43-year-old mother of two who works in finance, the fallout from a teeth clenching habit that she was unaware of happened more suddenly, one weekend two years ago. “I was trying to be super-healthy, eating a carrot. And then I heard this crack in my jaw.” It felt like it had become misaligned and she could not close her mouth properly.
However, by the time she saw her dentist on Monday, it was back to normal. They took X-rays and said that although it looked fine, if it were to happen again she would need to see a specialist.
Six months later it did happen again, while abroad on holiday, and, unlike the previous episode, caused a lot of discomfort. “I had this pain from my jaw to a headache. I never had headaches.”
On returning home, her previous dentist had moved and the one she saw this time said the problem was a wisdom tooth, referring her to a specialist for its removal. Doubtful of that diagnosis, and recalling what the previous dentist had said, she googled the symptoms and consulted a nurse in the family. Becoming convinced it was TMD, she returned to the dental clinic, suggesting she needed to be referred to a different sort of specialist.
“It was very frustrating,” she says. This time she was referred to Dr Smith in Bray. “Apparently, I have overflexible joints, which in itself is not a problem but if you clench, this is what happens.” She was given a customised mouthguard, which protects the teeth and puts the jaw joint in a more restful position. “During the daytime I have to be more aware I am clenching.”
Work stress is definitely what triggers it, she says. “It happens when I’m at my laptop, if it’s a tough day.” But since becoming aware of the habit and using the mouthguard, she has had no recurrence of problems with her jaw.
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