Smile a perfect smile, but don't laugh ... we have officially lost our dentures

It was wild in '68, man. We marched against the Vietnam war, queued to see Hair and smoked dope. We wore kaftans, mini-skirts ... and false teeth.

The gummy truth about the swinging Sixties is that while some Britons were puffing on joints, many, many more were sucking on dentures. More than a third of us, in fact.

But today, like the Beatles, false teeth are becoming a memory: 84 per cent of us, according to the latest official figures, now have all our own teeth, against 63 per cent in 1968.

While the improvement in the nation's dental health - due to the NHS, school check-ups, fluoride in toothpaste and improved diet - has undoubtedly raised the quality of life of individuals, it has lowered levels of hilarity across the nation. For as our real teeth have stopped dropping out of our mouths, false ones have gradually dropped out of the nation's comic consciousness.

Difficult though it may be for today's fluoridated and flossed youth to imagine, dentures were ubiquitous in the first eight decades of this century. Millions of people in their 20s and 30s wore them, whereas today they are largely restricted to the over-65s. They were considered very funny, ranking alongside mothers-in-law, bloomers, glass eyes and fat men in deckchairs as objects of mirth.

The nation fell about when, after one pre-war Buckingham Palace garden party, a set of dentures was found embedded in an abandoned meringue in a royal rose bush.

False teeth were a stock-in-trade of music hall comedians. In his act Norman Evans, a Northern stand-up comic of the Forties and Fifties, dressed up as a very fat housewife, gossiping over the garden wall while chomping on a set of false teeth and shifting an enormous bosom about. Audiences loved it.

Keith Waterhouse once wrote about false teeth jumping off the table during the great Hunslet earthquake, and dentures clattered regularly across the acts of post-war comedians from the Goons to Ronnie Barker.

The idea that false teeth are funny lingers in joke and novelty shops. Seaside-rock shops still sell pink-and-white sets of sugary gnashers which will, if eaten, surely advance the day on which the holidaymaker has to put real ones in his mouth. Clockwork false teeth which clatter across the table still sell well. A set features on the cover of the Guinness A-to-Z of Jokes, although the book doesn't actually contain any false- teeth gags.

Its companion volume, the Guinness Encyclopaedia of Jokes, has one about a restaurant customer who sneezes so violently that his false teeth fly out and shatter against the wall. "Don't worry, sir," says the waiter, "my brother can get you another pair." Ten minutes later he returns with a new set which are a perfect fit. Impressed, the diner says, "Your brother must be a good dentist", to which the waiter replies, "Actually, sir, he's an undertaker."

In the 19th century this would have made perfect sense, for teeth for dentures were often obtained from corpses. The British Dental Association's not-for-the-faint-hearted museum in Wimpole Street, central London, contains several sets of "Waterloo teeth" - so-called because the battlefields of Europe were an excellent source for the enterprising denture manufacturer.

"Dentistry has long had an uncomfortable, painful image, and has been the butt of humour because people make jokes about the things they fear," says the BDA's scientific adviser, Dr Peter Gordon. "Today people have better teeth, techniques are better and fewer people wear dentures, so perhaps they find less to laugh about.

"When I qualified, in Sheffield in the 1960s, some people still regarded having dentures as a status symbol. I remember one young woman of about 20 coming in with her mother. After an examination she was told she needed one tooth out and a couple of fillings. The mother was outraged. `Our lass isn't having fillings!' she cried. `She can have dentures, like her mum and dad. We've paid our National Health!' She went off in high dudgeon when we refused to do the extractions.

"In the past some young women had all their teeth taken out and replaced by dentures as a 21st birthday present, or as a form of dowry before marriage."

Today, says Dr Gordon, the idea of being known to wear dentures fills most younger people with horror: "The modern body image includes having a good set of white teeth. People want the Cindy Crawford smile."

Roy Clarke, Yorkshire-born writer of the television comedy Last of the Summer Wine, whose oldie characters Compo, Foggy and Clegg are all denture wearers, blames the decline of the false-teeth joke on political correctness.

"False teeth, wooden legs and surgical trusses used to be a standard area for comics," he says. "Everything was fair game.

"People don't make jokes about such things nowadays because of body- consciousness. Before the 1960s, certainly here in the North, there was no consciousness of style. The attitude, in fact, was anti-style. People who dressed stylishly or took too much care of their bodies were regarded with suspicion.

"If you were 50 you were expected to look 50. There was nothing wrong with getting a bit old and fat and having a laugh about it.

"This terrible self-consciousness didn't appear until the 1960s. Now comedians are afraid of doing anything that might give offence."