Should you always believe what your dentist tells you? Dina Rabinovitch sampled advice from both the private sector and that vanishing species, the NHS dentist - and was left feeling distinctly down in the mouth
Theresa Sturley, a TV producer, had what dentists call an "open bite" and what the layman might call buck teeth. She went to several dentists in London, who told her that they could fix the problem for her, but it would involve breaking her jaw - a painful and very expensive procedure. Ms Sturley balked at the idea. Two years later, she moved to the US for work, and went to see a private American dentist who gave her a simple set of braces to wear, which corrected the problem in months.

"The message from all the British dentists was: they'd have to break my jaw, but if I put my trust in them I'd be happy with the result," Ms Sturley recalls. "The US approach was to spell out all the options. The dentist said he could break up my jaw and do a lot of fancy surgery - but only if I wanted the most perfectly aligned mouth in the country.

"What's more, in the US you can ask questions. You're a consumer, and treated as such - it makes you feel more confident that they can deliver what they say."

According to a report from the think-tank Demos, to be published next week, the British are moving towards US-style consumer dentistry. By 2010, the report reckons, most dentists will be private practices, and the British public, used to lying back in the dentist's chair and thinking of hairy nostrils, will have to sit up and become a discerning customer of dental care. But just how do you find a good dentist?

In America, where I was brought up, there is a tradition of people caring for their teeth. So ingrained is it that I would be as likely to forget to change my baby's nappy as to skip the children's dental appointments. But many Brits are far more casual about going to the dentist, waiting until serious problems develop before they make an appointment. Part of the reason for this could be that British dentists' surgeries have traditionally been grim, unwelcoming places, the stuff of Monty Python sketches.

Another, more frightening, reason may be that the British have little faith in their dentists. Ms Sturley's story is just one of any number of horror stories people will tell you about poor dental care. The Demos report has some alarming conclusions, too. The think-tank ran an experiment in which it took people to have a filling done, and then immediately took the same patient to a second dentist. In 50 per cent of the cases the second dentist insisted that the filling needed redoing. This, says Demos, shows either that the quality of the fillings being done is questionable, or else that there is simply a lack of agreement among dentists about what constitutes a good filling. Which raises the question - well, if they don't know, how are we supposed to?

The British Dental Association told me: "It's difficult for the average person to know who is a good dentist. It's like conveyancing - you only know if your conveyancing's been done well if your house is still standing after five years; with a filling, you will only know if it's a good one if it is still in place five years on."

The Demos report says most people, whether choosing NHS or private dentistry, base their choices on appearance: how friendly the dentist is, how cheerful and clean the surgery. As more and more dentists turn to private care because they cannot afford to stay in the NHS (although, apparently, 85 per cent of patients are still NHS) and competition hots up for patients, the nightmare surgeries of slightly grubby men surrounded by piles of dated magazines, probing away at your teeth, are being replaced by cheerful pink-and-lavender-coloured premises, with the inevitable, widely smiling New Zealand receptionist and a clean-shaven dentist who wears a jacket and tie and shakes your hand as you come in. But how much faith can you put in appearances?

At least there is the consolation of knowing that NHS dentists are subject to regular checks on the quality of their work, carried out by the Dental Practice Board in Eastbourne. Private dentists have no such checks: there's no central register of private patients to check up on, as there is for NHS patients. But external checks are neither here nor there, according to one dentist who told me: "Dentists who are honest will admit they have to lower their standards to do NHS work, because we simply can't afford the same resources on what the NHS pays us."

I spent two days taking my teeth round the incredible variety of private and NHS dentists now on offer, pulling names out of the phone book ("dentists" comes after "demolition" in the Yellow Pages). The advent of the private dentist means that you can now get your teeth cared for using everything from laser treatment to hypnosis. And for all of you who thought dentists are just the sad ones who never made it into medical school, I have to report that there is a Lord Colwyn who is a dentist in London's Wimpole Street, who also has his own dance band, and treats patients with acupuncture.

My first stop was a private dentist specialising in being "warm and holistic" and in "dental phobia management", according to his advertisement. The warm approach began with a handshake, and an invitation to sit in a lush, black leather dentist's chair. I told him that I was here for a check-up but I'd been getting a shooting pain in one of my teeth (which was true, but I knew the cause, and wondered which dentist would spot it).

"Nothing that's got you too down, I hope," he said sympathetically. "Not requiring Prozac for it?" I thought this was a joke till he carried on, "I see a lot of Americans in this practice, and a lot of their youngsters are on Prozac; I feel like shooting the physicians." The violence of the emotion, expressed in the same gently soothing tones, had me covertly checking the room for exits.

Then he looked in my mouth. "Hmm, this is really unusual," he said, inducing immediate dental phobia. Then he added: "I can't see any problems at all. These are really good teeth. Most people have some problem."

He then said, "Ahh, but you are having some trouble opening your mouth, aren't you?" "I am?" I asked, opening my mouth wide in some amazement. "Ahh, I see," he said, "it was just that your defences are up."

"So what's the television for?" I asked. Wide-screen, matt black, it was right next to the chair, and just under the stacks of carefully wall- mounted stereo equipment. The stereo was for the soothing music, of course; the television turned out to be for watching a video of my teeth as he probed them with a tiny camera. Teeth on the big screen: that pinky-red stuff, that's your gum, but it looks like a womb, sheltering these small white craters - you start to feel really protective towards them.

For pounds 45 (over the phone I'd been told it would cost pounds 25, but then he took some X-rays - without asking me - and that added to the cost) he told me that only an idiot would mess with my teeth, but that I should floss religiously. Also, he wrote out the name of a mouthwash called Yum Yum.

Next stop Beauchamp Place, round the corner from Harrods: a waiting room packed with ladies who lunch (on sweets?), tweedy types, and a dentist whose surgery walls were plastered with his New York and London Marathon certificates. This visit cost me only pounds 30, but that's because I didn't let them take X-rays.

Before writing this piece I'd never set tooth in a private dentist's surgery, so I didn't know what to expect, but to me these premises in Beauchamp Place looked as tatty as the NHS dentist I visited as a child - complete with out-of-date copies of Private Eye - certainly nothing like as swanky as the holistic practice. No music, and no television, either.

Lying back in the chair, I was treated to a ceiling decorated with pictures of smiling actresses and models cut out of magazines. I asked if there were any NHS dentists in Knightsbridge.

"Not one," answered Marathon Man. "We've been private for about 10 years. Nobody who can help it is NHS any more, not on the fees the Government pays. It's impossible." He said it defensively, as if he felt he'd surrendered some principles along the way.

Checking my teeth, he said: "Mmm, your teeth are virgin, beautiful. Well, OK, if I was looking for problems I might say that filling's coming up for replacement."

We decided to leave it, though, and he sent me off bearing samples of Sensodyne. "Oh, please; we get them free; we've got loads."

Back out on the street, and there wasn't an NHS practice for miles. The nearest I could find was five stops away on the tube. Here, up dingy stairs, the receptionist was smoking with a friend and the premises were quite filthy - dirty floor, bursting bags of rubbish. No soothing Monet posters on the walls, but instead, dozens of snapshots of grinning children, each with their name and age carefully marked in red felt-tip underneath. One of the pop radio stations was playing.

There was no soothing patter from the dentist, either. Just that reekingly familiar sensation, straight from childhood, of staring up nostrils and smelling faintly rank breath. Instead of the conversational gambits I've come to expect, out comes, rapid as gunshot, a series of numbers and letters: F5, H, 2, 6 ...

This NHS dentist told me that he couldn't be sure without X-rays (which I said I didn't want) but in his opinion two of my teeth could be developing minor holes, and my fillings needed filing down. I told him I'd make another appointment to get the work done, and he said the cost would be pounds 21.72, then added: "And I'll take pounds 5 for today's visit." He gave me a printed estimate for the work and a receipt for the pounds 5. I left with the distinct sensation that he had suggested the work in order to make some money. The next day, visiting another NHS dentist, I discovered that the charge for a consultation is pounds 4.12, not pounds 5.

Before I started researching this piece I assumed that I'd be leaving private practices with huge estimates for pointless work. In the event, the only dentist to suggest unnecessary work was an NHS practitioner. But none of the dentists I saw, private or NHS, correctly identified the source of the pain in my teeth - a simple matter of sensitivity to sweet foods.

The reason I know my problem is because I have found an exemplary dentist, in one of the less garlanded parts of north west London and she works for the NHS. Having seen more dentists than I care to smile at this week, I'd say that the way she practises dentistry is as good a set of guidelines as possible for evaluating who is a good dentist.

In this city at least, she is a rare bird and people travel far to be treated by her. She never does any work on your teeth without explaining it first, and trying to show you - with mirrors (she craves a little video but can't afford one) - why it needs doing. She never uses a frightening instrument, and she lets children first hold any instruments she is going to put in their mouths. She also carries out work - such as veneers - on the NHS that most dentists will only consider doing privately.

It might not have led to quite the same headlines, but if Martin Amis had asked me, I could have told him to get his teeth checked in Neasden, before spending all that money in Manhattann