In the course of their life, the average Briton can expect to spend nearly £15,000 on looking after their teeth - if they have 'gone private'. But British teeth generally are in a mess: the average Briton has lost eight of their 32 adult teeth by the time they turn 45, according to the latest Adult Dental Health Survey.

Much of the problem lies with our national dental infrastructure - and it is surprising that opposition politicians are not getting more mileage from this. For instance, only 18 million adults - 44 per cent of the adult population - are currently registered with a dentist, according to the Dental Practice Board.

The shortage of dentists 'has reached crisis point', according to the dentists' trade union, the British Dental Association. In England, there is now a 9 per cent 'undersupply' of dentists, according to a report from the Primary Care Dental Workforce Review in February. Many parts of the country have no NHS dentists at all - as the queues of people in Carmarthen, Scarborough and other locations showed when new dentists opened.

The funding system also puts people off. Adults going through the NHS still have to pay 80 per cent of their costs. And a report last year from the Office of Fair Trading (OFT) showed that the £1 billion private dental market 'is not working well for consumers in some key respects'. The OFT was concerned that 'consumers often lack basic information on prices, quality of services and what treatments are available on the NHS '.

We know that there are regional variations in what people pay for dentistry, but there is very little reliable information. People can pay twice as much in some parts of the country as in others.

'A lot of private dentists have a near monopoly, so they can charge what they like,' says Philip Blackburn of researcher Laing and Buisson. 'There isn't any downward pressure on fees.'

Denplan, which runs dental payment schemes with private practices, says the average monthly cost for adults is £15.50. This translates into annual costs of £186 and lifetime costs (over 80 years) of £14,880. The Denplan data is probably a good indicator of average costs per person. If your teeth are good, you might pay very little over your lifetime; if they are not so good, you could pay twice what others pay.

People who want to pay their dental costs monthly can ask their dentist to assess their teeth for a Denplan or similar scheme. When this is done, the dentist quotes a monthly figure and the patient pays this until the next assessment a year or two later. Laing and Buisson believes costs are likely to rise in future, as technology becomes more sophisticated, more treatments become available and dentists' equipment becomes more expensive.

People are also keeping their teeth for longer - especially since the practice of parents giving their children a 'clear out' for their 21st birthday to prevent future toothache died out in the Sixties.

The government says it hopes to tackle the problem of the shortage of dentists, but if it fails, some dentists will be able to set their prices higher.

The problem is that few people can tell a good dentist from a bad. We may be able to judge if a dentist is friendly or has a good chairside manner, but few of us can judge the final product of most treatment. Nevertheless, we can all take steps to keep our teeth healthy. These go beyond what the dentist usually says - flossing and regular brushing - and could involve such steps as asking your dentist to draw a map of your mouth and telling you where your vulnerable points are, and researching oral health measures on the internet.

The way you pay can also encourage you to do the right thing. Insurance and payment schemes can work out quite effective. It is not unusual for people to receive more in treatment than they pay out in premiums. The Denplan payment schemes, for instance, are actually contracts between the individual patients and their dentist, with Denplan providing the administration. Dentists will have their own ways of pricing and may, in effect, subsidise some patients by charging others more.

The website insuresupermarket.com lists more than 40 dental cover plans. Cover can cost 'as little as £5.95 a month', it says, urging people 'to shop around as bigger brands can cost nearly three times as much'. The OFT also urges consumers to be proactive and ask in advance for guide prices on treatments and services, written and costed treatment plans (including alternatives) and itemised invoices. Only 40 per cent of dental practices were publishing guide prices when the OFT did its research last year.

The framework for dentistry is due to change next year. A simpler charging system for the NHS is due in October 2005, with perhaps just three charging bands instead of the current 300. Overall, people receiving NHS treatment will still pay £500 million between them - as they do now - but individual prices may rise or fall.

Just as significant will be the relationship NHS dentists have with the NHS. They are now paid for the work they do, but the government may be considering a system that pays by the number of clients they have, and which could encourage them to do less remedial and preventative work.

'Your guide to private dentistry' is available free from the Office of Fair Trading on 0870 60 60 321.

The cost of going private

Procedure Cost £

Consultation 82

Examination 45

Peridontal care - 20 minute session 45

Hygienist visit - 20 minutes 30

Fillings (small amalgam) 50

Bridge (per unit) 450

Tooth extraction 50

Endodontics (root canal treatment) 300

Orthodontics (braces - fixed) 1,750 - 2,500

Implants (single tooth) 1,500 - 2,500

Note: Costs vary considerably. These costs are based on prices charged in 2003 in large cities and city centres. Source: Denplan

We spend £442 million a year on toothbrushes, toothpaste and mouthwashes each year, according to researcher Mintel.