Your health questions answered

What can I do about my clicking jaw? Am I getting enough vitamin D? And is my prescription toothpaste safe to use?

BITING PAIN

Q. My jaw has been clicking since an extended visit to the dentist some months ago. Sometimes my jaw hurts, feeling as if top and bottom are wired together, and sometimes it hurts on yawning and chewing but nothing that isn't fixed by an over-the-counter painkiller. My GP gave me 10mg amitriptyline but it made me so dopey in the mornings that I gave it up. A course of Indian head massage helped my general inability to relax. But I never know with a minor joint condition like this if I should exercise my jaw by chewing or rest it by eating baby food? Are there any long-term, negative effects of this kind of problem, or is it best to just learn to live with it, take the occasional aspirin and keep clicking? How much does it really matter?

A. The click in your jaw is coming from your temporomandibular joint (TMJ), and technically you have a condition called TMJ dysfunction. The TMJ is the joint between your jawbone and your temporal bone (which is part of the skull). It is quite a complicated little joint, which is capable of withstanding the incredible muscular force that is needed to chew food. Inside the TMJ, there is a tiny cartilage, similar to the cartilages that are inside the knee joints. Every time you open and close your jaw, the cartilage slides forwards and back. If the cartilage gets bruised, torn or stretched, it fails to stay in the right position. The click occurs as it slips back into its correct position as you open and close your jaw. If the cartilage fails to return to its normal position, you may find that your jaw gets partially locked temporarily. TMJ dysfunction only matters because it can be painful and it can interfere with chewing. It often gets better without any specific treatment. The best advice is to be gentle on your TMJ, and avoid any chewing that exposes it to intense muscular forces. Chomping on big, crispy, raw apples and day-old French bread will only make things worse. But it is certainly not necessary to restrict yourself to baby food. Taking the odd aspirin or ibuprofen is a good idea. Tense people seem to get more TMJ problems, so anything you can do to relax will also help. If you want to see a tiny cartoon movie of what is happening inside your TMJ, have a look online at www.rad.washington.edu/tmj/anatomy.html.

A PLACE IN THE SUN

Q. We are told that we need sunlight to make vitamin D, and that vitamin D is necessary to prevent osteoporosis and brittle bones. Is it possible to make vitamin D while sitting in a double-glazed conservatory? Or do I have to go out into the open air to get enough sunlight to make vitamin D?

A. Human skin makes vitamin D when it is exposed to sunlight, which contains ultraviolet B (UVB) radiation. There is less UVB in winter sunlight than in summer sunlight, and the further north you go, the less UVB you get from sunlight. People with dark skin and the elderly make less vitamin D from sunlight than fair skinned and young people. Air pollution and the ozone also cut down on the amount of UVB that gets through the atmosphere. Ordinary window glass cuts out about 95 per cent of UVB, so sitting in your conservatory is a very poor way of making sure you get enough vitamin D from sunlight. But you don't need all that much real sunlight to make vitamin D. It is estimated that about 30 to 60 minutes of sunlight each day on the exposed areas of the face, neck and hands is enough in the summer. In the winter, when sunlight is weaker, it takes longer. It is also possible to get vitamin D in your diet, or by taking supplements. Unfortunately, not many foods contain much vitamin D. Margarine and low-fat spreads are fortified with vitamin D, you can get a big dose from a spoonful of cod liver oil, and kippers and sardines are pretty good too.

THE TOOTH HURTS

Q. My dentist has recommended a new toothpaste - Duraphat 2800 Fluoride Toothpaste. It is apparently only available on prescription. Are there any drawbacks or side effects from using it?

A. Duraphat 2800 toothpaste contains between two and three times as much fluoride as ordinary fluorinated toothpaste. It is designed to prevent dental decay in people who are at particularly high risk of dental problems. A few studies have shown that it is more effective than ordinary-strength toothpaste. I'm not quite sure why it is only available on prescription from dentists. It is definitely not recommended for children under the age of 10. If children get too much fluoride, there is a risk that their teeth will become permanently mottled or discoloured. As long as you use the high-strength toothpaste according to your dentist's recommendations, there shouldn't be any drawbacks or side effects. And it may well lead to healthier teeth in the long term.

Readers write

AA from Devon has his own method for removing ticks:

"For many years, I have suffered from pesky, little ticks when gardening, especially when there is bracken. I soak a piece of material with any spirit available - brandy, whisky or gin - and hold it over the tick. It will be sozzled and relax its hold. Alcohols are also antiseptic."

Please send your questions and suggestions to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182 or e-mail to health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally to questions.