Your money where your mouth is

Teeth not white enough? Try this. Or this. Nick Walker on a growing market

In our culture, pearly whites represent not only health, but beauty and glamour - that movie-star smile. Which explains why competition in the tooth-whitening toothpaste market is so fierce. In 1994, we bought more than 178 million packets of toothpaste, about three each, making more than pounds 194m a year in sales. And, though generous estimates give tooth-whiteners around 5 per cent of the market, taking polishers' and smokers' toothpastes into account, Beauty Counter magazine states: "In the US the whitening-toothpaste sector alone now accounts for 5 per cent of the market ... and it will grow to take a similar share of the UK market in the next two to three years."

Two years ago, sales of tooth-whitening toothpastes were growing by 40 per cent each month. Though Grafton International, which kick-started the trend by importing Rembrandt from America, is reluctant to give exact details of its growth in the face of increasing competition (some eight new brands now make tooth-whitening claims identical to Rembrandt's), spokesman Jon Hardwick says: "Retailers are now selling one-third more in value terms without moving that many more tubes. There can only be one reason for this: increased sales of whiteners, which, at the top of the market, are that much more expensive."

Indeed. That movie-star smile has a price. Tooth-whitening toothpaste can cost roughly eight times more than ordinary toothpaste - a 50ml tube of Rembrandt retails at pounds 7.75, a Boots' version at pounds 5.99. High research and formulation outlay, they claim.

A 1984 European Commission directive outlawing the bleaching of teeth by dentists using carbamide peroxide has fuelled the popularity of whiteners. Carbamide peroxide reacts in the mouth to form hydrogen peroxide - bleach - the substance banned in the directive because of its carcinogenic potential if ingested. The British Dental Association (BDA) wants the directive revoked: it says a trained dentist will ensure safe usage.

Many tooth-whitening toothpastes like Rembrandt, and the forthcoming "super toothpaste", Janina Ultrawhite, use a different technique. Enzymes are used to break down surface deposits, or the "stain matrix". Teeth are made from porous material and it is very easy for heated oils or fats to penetrate the tooth and leave a stain. Other marks can appear by sticking to bacteria which collect on the tooth's "pellicle" layer - its outer skin. Enzymes break down the layer of bacteria which forms the "stain matrix", stopping stains from gripping on to the surface of the enamel. Many products use papain from the papaya fruit, which reacts with the bacteria's metabolism and stops build-up.

Along with bleaching and enzymes, there are two further processes which claim teeth-whitening powers. Abrasives such as Pearl Drops (technically a tooth polish) work in an obvious manner. All toothpastes are abrasive to a greater or lesser degree; polishes are at the higher end of the scale. Titanium oxide, also used in many suntan lotions, works like a dye, plugging gaps in the teeth so they appear whiter. Macleans Whitening and Colgate Platinum are two more whiteners recently in the chemists. The BDA says Colgate uses a fine abrasive. Macleans employs sodium tripolyphosphate, said to react with calcium in the stain matrix, weakening it and making normal cleaning agents more effective.

Claims that a product actually whitens teeth are difficult to substantiate. At the moment, manufacturers have no legal obligation to do so. Despite differences in ingredients, the exact distinction between a polish and a whitener is not immediately clear, although Boots will tell you whiteners "whiten" and polishes "add lustre and shine". Smokers' toothpastes, on the other hand, are often simply more abrasive. Cathy Mayne of Rembrandt is clear on one thing: "The toothpaste market is saturated. This was clearly seen with baking-soda pastes, which simply took away from the sales of other toothpastes. I'd say it's all about marketing."

TOOTH TALK

Rembrandt Natural, pounds 7.75 for 50ml

"It didn't make much difference. You're supposed to use it with a special toothbrush, but it made my gums bleed. It tasted all right, but not as minty as my normal toothpaste. I don't smoke and I drink hardly any tea or coffee, so maybe my teeth are as white as they are going to get."

Boots Tooth-Whitening Toothpaste, pounds 5.99 for 50ml

"It didn't feel particularly abrasive and it didn't make my mouth feel as clean as baking-soda toothpaste does. But it did make my teeth feel different to the touch. My teeth at the front did seem to be a bit whiter, but maybe that's because that's where it's easiest to brush. I will continue to use it to see if there's a substantial difference - but the price is an outrage."

Denivit tooth polish, pounds 1.45 for 50ml

"It tastes awful, sort of aniseedy. You're supposed to use it on a dry brush, which I didn't like at all. I smoke and drink a lot of coffee, so I have stains behind my front teeth. Although I tried my best to use as much of it as possible there, I can't really see much difference. I would much rather go to the dentist and get my teeth polished."