Mouth Piece 5. How toothpaste works.

I would not be surprised if a reader of my last post raised an eyebrow. That simple? Really?

In theory, yes, I believe it is. In practice, though, most people eat processed food; and to preserve their teeth and gums in the way I described, they must eat clean. Suddenly, not so simple at all.

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I have become sceptical about many practices of the dental profession. The more treatment people need, the more money dentists make—so can they be trusted? Well, I do not believe dentistry is a conspiracy. Faced with patients who coat their teeth with sugar, which they fail to clean off quickly enough, dentists provide a remedial service, mending the damage that results. They may remind us to eat less sugar or clean our teeth better; but ministering to our overall health is beyond their remit. The hourly state of our teeth is our responsibility, not theirs.

Though we are not routinely told that enamel can reform and dentin regrow, orthodox tooth care provides the clues. We learn, for example, that calcium is good for the teeth. I assumed calcium helped them grow well. But if that is all calcium does for teeth, why are we still advised to consume calcium once our teeth are grown? Logically, if calcium is good for mature teeth, then teeth must be subject to repair, like bone. Their structure must be dynamic, in common with other bodily tissue.

I also assumed calcium benefits teeth via the bloodstream. We consume, say, milk, and its calcium enters the blood, reaching our teeth from within. In fact, I now understand that dairy products, for example, also benefit the teeth topically. In other words, they mix with saliva, and when that saliva bathes our teeth, the minerals (and proteins) in dairy foods adhere to the teeth and are laid down directly in the enamel and dentin, through chemical reactions. This happens with all mineral-rich foods--dairy is just the best known The process is one of gain and loss: minerals and proteins are constantly lost from the teeth and replaced, as they are in other body tissue. If an acid solution can remove minerals from the teeth, then an alkaline solution can reverse the process and add them. Demineralisation and remineralisation occur all the time on tooth enamel, according to the pH of the saliva.

This became even clearer to me when I considered toothpaste. We do not eat toothpaste, we brush it onto our teeth. Why? I had thought of toothpaste as a glorified cleaning product, along the lines of kitchen cleaner. But if that were the case, it should contain only soap and abrasive. In fact, toothpaste contains minerals such as calcium, phosphate, and fluoride. What reason could there be for including such minerals except to lay them down into the fabric of our teeth? Toothpastes also contain buffering agents to make the mouth less acidic. They help provide the neutral conditions for the reactions to take place that incorporate minerals into the teeth.

So although the dental industry makes its money from remedial work, the intention behind its products is not just cleanliness but also the daily protection and mending of teeth on a sound scientific basis.