If modern life leaves you grinding your teeth in frustration, you are not alone. Dentists are recording increasing cases of involuntary teeth-grinding, known as bruxism. The problem is thought to affect one in 10 of us.
Dental surgeon Dr Nigel Carter, head of the British Dental Health Foundation, explains: "There's no doubt that teeth-grinding is an increasing problem - and a feature of the stress brought on by modern lifestyles."
Most cases occur during sleep, although bruxism can also affect people when they are awake, with some clenching the jaw at the same time. Although cases of bruxism are mostly seen among women in their twenties and thirties, when the pressures of combining a career with marriage and family may be greatest, dentists are noticing a rise in adolescents, too.
Dr Shivani Patel, a specialist at Elleven Orthodontics in London, says: "Some young children grind away their milk teeth at night time, but the habit goes away naturally.
"Of more concern are the children who are grinding down their new adult teeth. I am seeing patients aged 12 or 13 who are stressed by exams and begin grinding as a result. Once you grind down to the dentine level, damage is irreparable, and you become very sensitive to heat and cold, too."
Our teeth are built up of layers: on the inside is pulp - soft tissue that houses nerves and blood vessels. This is the part that hurts when teeth become decayed. Protecting the pulp is dentine, calcified tissue that supports the outer layer of enamel.
When dentine becomes damaged, it can lead to faster tooth decay and even destroy the shape of the mouth. Faces can become visibly shorter, by which time there is little that can be done to reverse the process. Other problems, according to the Bruxism Association, range from headaches, aching jaw and facial muscles (myalgia), earache, tightness/stiffness of the shoulders, sleep disruption and inflamed and receding gums.
In severe cases, temporomandibular joint disorder occurs (TMJ), causing clicking or popping noises as you move your mouth, muscle spasms around the jaw, and a feeling that the jaw is stuck. This can make eating difficult, resulting in pain around the ear, cheek or temple.
Dr Carter says anti-inflammatories can help with pain, while anti-anxiety drugs such as diazepam are effective muscle relaxants. Osteopaths, chiropractors and psychologists all use strategies to reduce tension in the head and neck area, as well as addressing underlying mental stress.
The Bruxism Association recommends hypnotherapy, and some studies support its use. In 1991, a report in the American Journal of Clinical Hypnotherapy found it could reduce grinding noticeably, with results lasting for up to 36 months.
According to Dr Prasanta Banerjee, dental expert at Riverbanks Clinic, Luton, injecting Botox (botulinum toxin) into the masseter muscles of the jaw is also worth trying.
The grinding itself can be prevented through use of a plastic device (called an occlusal splint), worn at night to protect teeth. Dr Carter adds that if unconscious tooth-grinding occurs during the day, teaching the patient to be aware of it can break the cycle.