A mouthguard at night can make jaw pain WORSE

Tooth grinding at night is on the rise, and it’s wearing down our teeth and causing jaw pain. that’s been the thinking for the past few years as the UK succumbs to an ‘epidemic’ of tooth grinding — six million adults are thought to be affected.

the habit, otherwise known as sleep bruxism, has been cited by dentists as a key cause of worn, cracked and broken teeth. It is also said to cause temporomandibular joint disorder (TMD) — excruciating facial pain which originates in the jaw.

the temporomandibular joint connects the lower jaw to the skull in front of the ear.

It has long been thought that overuse of the muscles surrounding the joint through teeth grinding puts pressure on the joint, causing the pain.

TMD can also lead to jaw ‘popping’ and clicking and difficulty opening your mouth. the NHS suggests up to 30 per cent of adults experience it.

the belief that bruxism is the leading cause of TMD has led to the use of treatments such as mouthguards to prevent teeth grinding (that can cost up to £700 privately).

hundreds of clinics in the UK also offer Botox injections into muscles around the joint, to reduce the force of the bite.

But a U.S. study has found that people diagnosed with TMD are actually less likely to grind their teeth, suggesting mouthguards or jabs may be pointless for many. Some experts believe these treatments could make some people’s pain worse.

the U.S. researchers recruited 124 women who had been diagnosed with TMD, and 46 without it and studied them for two nights in a lab. the volunteers were hooked up to a device that measured muscle activity in the jaw to identify periods of teeth grinding.

More than half of the TMD group had been told by a medical professional that they suffered from bruxism, compared with 15.2 per cent of those with no jaw pain who’d also been told they ground their teeth.

Yet according to readings only 9.7 per cent of ‘TMD sufferers’ ground their teeth, compared with 10.9 per cent of those in the control group.

Both groups spent on average less than one minute per night grinding their teeth. And astonishingly, TMD sufferers who did grind their teeth at night reported less pain than those sufferers who didn’t grind their teeth.

Lead researcher, Karen Raphael, a professor of oral and maxillofacial pathology and medicine at New York University College of Dentistry, believes sleep bruxism is unconnected with jaw pain.

‘Many people grind their teeth a little at night, but people who suffer from the most severe pain are actually the least likely to grind their teeth at night,’ she says.

She says TMD is actually caused by clenching your teeth in the day and muscle tension at night (which a mouthguard won’t help).

‘People with TMD tend to more tooth to tooth contact during the day, and also have more muscle tension during sleep but they do not grind their teeth more,’ she says.

Women suffer more than men so hormones may be involved, she adds. TMD can also be caused by arthritis or injuries to the jaw.

But the belief that sleep bruxism causes TMD is widely held, and so patients are sold expensive treatments they don’t need, says Professor Raphael. She says dentists aren’t purposely deceiving the public. ‘they are trained to believe this,’ she says. Furthermore, while mouthguards can alleviate TMD pain for some, in others they can cause or exacerbate facial pain, possibly because they make muscles more tense.

And Professor Raphael has found that Botox injections into the jaw given to treat bruxism, can lead to bone loss of up to 30 per cent.

‘If treatment is repeated every three to six months, the bone may never have a chance to recover,’ she says.

Meanwhile, tackling bruxism by balancing the patient’s bite — with crowns and bridge work, or drilling down teeth ‘may make the problem worse’, says the U.S. National Institute of Dental and Craniofacial Research.

Professor Raphael even questions whether tooth grinding causes teeth to wear away, saying the evidence ‘is really weak’.

She says dentists can’t tell the difference between damage caused by grinding and tooth wear due to clenching in the day, an acidic diet with fizzy drinks and coffee, which softens the enamel, ‘making teeth more susceptible to damage from normal tooth-to-tooth contact, or wear due to poor enamel formation early in life’.

Dr Andrew eder, a dentist in London who specialises in tooth wear and tear, says the U.S. research is ‘based on a small group and needs to be looked at further’.

Professor Damien Walmsley, scientific adviser to the British Dental Association, concedes there is not enough evidence that dental intervention ‘stops sleep bruxism’.

‘But mouthguards do have some benefit in stopping tooth wear,’ he adds.

Dr Raphael says TMD can be treated using painkillers, icing the area and eating soft foods. ‘the best advice is to ask patients to concentrate on keeping their lips together, but teeth apart during the day.’