For thousands of British children, having a brace fitted is as much a part of the teenage experience as acne and boy bands. The inevitable taunts of "brace face" and "tin grin" are only the beginning of what often turns out to be a painful experience in more ways than one.

Regular tightenings can leave teeth too sore to eat solid food for days, and that first kiss may be elusive. Yet most adolescents will gladly submit to such inconveniences to avoid a lifetime of looking like Austin Powers.

For some, however, there is no longer a choice. A recent survey by the British Dental Association shows that a serious lack of orthodontists means patients in some parts of the country must wait up to four years for treatment.

While orthodontists say 60% of children in this country would benefit from corrective treatment, they are only able to treat about 25%. Warren Jones, vice-chairman of the BDA's central committee for hospital dental services, says: "The problem is extremely serious. There's a tendency to look on orthodontics as purely cosmetic, but people can suffer facial disfigurement or handicap, and orthodontics has a major effect on their quality of life."

Jonathan Sandler, a consultant orthodontist at Chesterfield Royal Hospital, agrees. "Children at my clinic are waiting up to 18 months to start treatment. This may mean an additional 18 months of merciless teasing over having goofy teeth, when with treatment they could blossom into self-confident young adults. What worries me is the negative social stereotyping that goes on. Boys with a missing front tooth may be wrongly stigmatised as aggressive, and there's evidence that teachers assign negative character traits to less attractive children."

For years, we have tutted contemptuously at American parents who pay up to £4,000 to give their children a Hollywood smile. However, it is becoming obvious that our own defective dentition is the joke. There are gags about "snaggle-toothed Brits" on The Simpsons cartoon show and US chat show host Conan O'Brien invariably pokes fun at Elizabethan dentistry when interviewing British guests.

The irony is that British children actually have a higher rate of tooth overcrowding than either US or middle European children. The reason is not clear, although some theories suggest that increasingly refined diets or decaying milk teeth interfere with healthy spacing. What is certain, however, is that orthodontic treatment is already much harder to come by in Britain than in the US and most other European countries.

Sandler says: "Some parents are already sending their children to private specialists, but it's something few can afford, so if nothing is done to rectify our current problems, there will soon be a critical lack of trained specialists within the NHS."

Catherine Woodman, 14, from Brentwood in Essex, was put on a waiting list for assessment a year ago, and has now been told she could wait two years for surgery to clear an impacted eye tooth in the roof of her mouth. Then she may have to wear a brace for two years. Her mother, Jane, says: "It's just shocking. She could be nearly 19 by the time it's all over. She's got GCSEs coming up, and does not need this added upset. I've investigated getting it done privately, but it would cost £2,800."

The BDA says the shortage stems from orthodontists' training being extended 15 years ago from one to three years - on top of an initial five-year degree in dental surgery and two to three more in general practice.

Jones says: "The average treatment lasts two years, so it was felt the training should be extended." However, there hasn't been enough funding to increase the number of training places in proportion. This means many orthodontists are now reaching retirement age, and hanging up their pliers faster than they can be replaced. One in 20 hospital consultants' posts are not filled.

There is also a north-south divide in training places, with around 50% of all new orthodontists (23 out of 50 each year) being trained in the south-east. Nearly all end up working within a 30-mile radius of where they were trained.

This has created an acute shortage of practice specialists, needed to leave hospital orthodontists free to concentrate on severe, surgical cases. Such specialists are usually better paid than hospital orthodontists, and this, too, means that more of them tend to congregate in London and the south-east.

Therefore, while London has one specialist for every 1,308 12-year-olds, there is just one per 4,692 in the West Midlands, for example. In some areas, such as Barnsley, where children are waiting four years for assessment and treatment, there is not one.

Delays are not the only problem. Once patients are assessed, confusion reigns over which conditions should be treated within the NHS. These range from the purely cosmetic, such as squint teeth, to cleft palates, or congenital problems where teeth have not developed and implants are needed. However, with no clear guidelines, some health authorities will treat some conditions but not others.

So what is the solution? The BDA is calling for urgent meetings with government experts. Jones says: "We understand there isn't unlimited money in the health service. But this government was voted in on a platform of equality of access to care and as far as orthodontic treatment is concerned, it's a postcode lottery."

He hopes some of the money allocated to the NHS in the budget will be used to set up additional training places. "Once we know what we're going to treat, we can get a better idea about how many extra specialists we need, and decide how to get them to the places where they're most needed; for example, by providing loans or grants to help them set up in poorly covered areas."