Pharmacy manager Chau An Bich had intermittent aches in her jaw but did not consult her dentist about it because she found the pain manageable.

Four months ago, the pain became more intense and she noticed a lump on the right side of her jaw. The area around it was also tender and sore, she said.

It prompted the 34-year-old to visit an ear, nose and throat specialist at Mount Elizabeth Hospital last month. She was advised to see a dentist and was referred to The Dental Studio at Paragon.

She had an X-ray taken of her right temporomandibular joint (the joint connecting the jawbone to the skull). Thankfully, it showed no growth or abnormalities.

Said Ms Chau, who is married to an auditor: "The dentist concluded that it was a muscle-related injury that was causing the ache and soreness and said it was most likely due to the grinding or clenching of my teeth."

She now wears a mouthguard when she sleeps to protect her teeth from the damage that occurs during grinding and clenching.

Bruxism is an involuntary movement disorder characterised by excessive clenching and grinding of the teeth. It can occur when a person is asleep, known as sleep bruxism; or awake, referred to as awake bruxism.

Symptoms include headache, neck and jaw pain, or dental symptoms such as cracked teeth, damaged dental restorations like broken crowns, and sensitive or sore teeth.

Some also present with symptoms of temporomandibular joint disorder such as reduced opening of the mouth, pain on opening, locked jaw, and joint sounds such as clicking or crepitations on opening and closing of the mouth.

Dentists say bruxism is caused by physical, psychological and genetic factors.

Stress and anxiety are highly associated with bruxism, said Dr Marilyn Loui, a dentist at Smile Central Clinic.

"The effects of suppressing emotions and motor activities result in several neuromuscular disorders. Chronic stress and the reactions triggered by it cause functional deficiencies of the nervous-muscle system (leading to bruxism)," she said.

The stress brought about by the Covid-19 pandemic has also led to an increase in bruxism.

Dr Lynette Ng, dental director at The Dental Studio, said: "Stressful situations activate the sympathetic pathways in a fight-or-flight response, causing jaw muscles to increase in tonicity, thus the clenching of teeth. Stress can also keep people awake at night, and insomnia or poor sleep patterns have been associated with worsening bruxism at night."

Ms Chau said the pain in her jaw could have been "exacerbated" by the anxiety she has been feeling due to the pandemic.

"The pain became intense only four months ago so it could be due to the stressors from Covid-19. I'm anxious because nobody anticipated such an outbreak and there is uncertainty as to how long this will go on for."

Dr Chua Ee Kiam, a senior consultant at the Prosthodontic Unit at National Dental Centre Singapore's Department of Restorative Dentistry, said changes in the job landscape, adjustments to a new working environment, disruptions to social activities and the fear of Covid-19 infection can cause an increased level of mental activity that may not be well addressed.

"The mind-processing activities often continue in the subconscious mode, during sleep, triggering jaw muscle activity," he said.

The National Dental Centre sees about 30 patients a month for bruxism and Dr Chua is expecting the number to rise due to the higher stress and anxiety levels during this period.

Patients with bruxism have increased by about three to four times at The Dental Studio since the end of the circuit breaker, noted Dr Ng, a prosthodontist. She now sees three to four patients a week with pain related to bruxism or requesting mouthguards as their old ones have been worn out.

She also reported an increase in the number of patients with fractured teeth that required extractions, root canals or crowns.

Manage bruxism with lifestyle changes

Bruxism can also occur in an individual if a family member suffers from the same problem.

A high intake of alcohol and caffeine, and medication such as antidepressants and certain illegal drugs, can also increase its occurrence.

Most people are not aware that they grind their teeth when they sleep, but become aware of the pain or its impact when they wake up with a headache or sore jaw muscles.

"The grinding forces can be as high as 80kg," said Dr Ng.

People may also learn about it when their sleep partners complain of the jarring sound of teeth gnashing together.

"The episodes can be transient, lasting a few seconds, and can go up to 100 episodes a night. Teeth grinding also varies significantly over time and may appear at certain periods of our lives, disappear and, for some, only to reappear again.

"As such, more than 80 per cent of bruxers are unaware they have this problem," she added.

Though bruxism cannot be cured, it can be managed through certain lifestyle adjustments.

Dr Loui said treatment for bruxism usually begins with an improvement to one's sleep pattern, reducing the intake of coffee, quitting smoking and limiting physical or mental activity before going to bed.

Apart from wearing mouthguards to reduce the damage to the teeth and jaw during grinding and clenching, pain medication can also help relieve the symptoms.

Dr Chua advised those with the condition to exercise regularly to try to reduce their stress levels.

However, he added: "Teeth wear and damage occur over a period of time and, often, patients see us only when the damage is extensive. A check with the dentist is a good start."