Book Extract #12: Toothpastes

Toothpastes are a little like dishwashing detergents in that there is very little difference between brands, and our choice of product is determined exclusively by how well they have been marketed.

Toothpastes are essentially abrasives in a gum or glycol base with some surfactants, colouring agents, flavouring and fluoride added.  So all they are designed to do is scrub plaque and embedded food off your teeth, impart some fluoride, and make your mouth feel fresh.

And they are mostly all the same (with one exception).  There is very little difference in composition between the generic brands and the top of the line “whitening” toothpastes.

But this hasn’t always been the case.  Several years ago the “whitening” toothpastes were premium products that actually did contain a whitening agent – peroxide.  They also contained sodium bicarbonate which is an effective defence against tooth decay.

The cause of tooth decay is not well understood generally.  We hear that it is caused by “acids” and are told to avoid acidic foods. This is only partially right.  Our teeth are essentially a mineral called hydroxyapatite, which is composed of calcium phosphate.  This is a chemically stable compound and is not easily dissolved by acids, certainly not any acids in the foods that we eat.

So when we are told to avoid acidic foods like orange juice (citric acid) or Coca-Cola (phosphoric acid) or soft drinks in general (carbonic acid), we are being misled, as none of these acids are strong enough to dissolve our teeth in the few seconds that they are in contact with them.

Here’s what happens.

When we consume sugar (which is the real enemy of teeth) it combines with proteins to form glycoproteins, which is plaque.  The plaque has a strong affinity for our teeth and coats them easily.  What happens then is that the glycoproteins are degraded by anaerobic bacteria, in a process that is remarkably similar to what happens in our muscles when we exercise.

Since the plaque has coated our teeth very effectively, and is essentially nonporous, it’s an anaerobic (no oxygen) environment.  What happens then is that anaerobic bacteria degrade the glycoproteins to form lactic acid, a relatively strong organic acid.  But since it forms at the very surface of our teeth, and is held in place by the plaque, it begins dissolving the calcium phosphate that your teeth are made out of.

So there is certainly a case for having a mildly alkaline component in toothpastes that will neutralise this effect, and sodium bicarbonate fits the bill beautifully.

Incidentally, desensitising toothpastes seek to reverse this process.  They do this by including calcium and phosphate in their formula, the idea being that they will combine to form the hydroxyapatite that your teeth are made out of and rebuild the surface (covering the sensitive part that has been exposed).

In terms of whitening, peroxide is the perfect whitening agent for teeth.  Mostly present as sodium percarbonate ( which as we have seen in section 5.2 is also a laundry bleach), they get away with calling it a peroxide as it is alternately referred to as sodium carbonate peroxide, due to an unusual molecular formula which is essentially three hydrogen peroxide molecules stuck onto a sodium carbonate molecule (2Na2CO3.3H2O2).

There was a time when each off the major toothpaste manufacturers had a whitening toothpaste on the market with this formula. Several years ago, that all changed, and although they were still called “whitening” toothpastes, the baking soda and peroxide disappeared from the formulas.  This was no doubt a decision made at a marketing level, in the hope that they could make the products cheaper, and make more profit, and that no one would notice.

In other words, they are treating you like mugs.

Unfortunately, however, someone did notice – in this case, Choice Magazine, who were the first to bring it to public attention.  So now the great con has been exposed – the toothpastes with fancy packaging that include glittering letters that claim to be whitening toothpastes will do no more to whiten your teeth than the generic Coles and Woolworths brands.

And it’s only Australia.  If you Google “whitening toothpaste” you will see that the products containing bicarb and peroxide are still sold overseas.  It’s only the Australian market where they think we are dumb enough not to notice.  In fact it is the marketing people who are the dumb ones, as their attempt to con the Australian public has now been exposed.

There is one exception to this, however – an American brand called Arm & Hammer.  Curiously, this well recognised brand in the USA made their name selling products based on bicarb soda and washing soda.  Toothpaste was therefore a logical extension of their brand name, and the addition of the sodium percarbonate makes it the only serious whitening toothpaste on the market.

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