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What causes cavities? How can I prevent them

Those dreaded words: 'You have a cavity in your back tooth'. How can we avoid the problem of cavities?

We'll look first at the graph pictured above (bear with me):

Stephan Curve

It's called the stephan curve, and it describes what happens in your mouth when you eat something sugary.

The middle red line is the PH or acidity of your mouth, if the blue line dips below it, cavities start to be formed. So we can see that a few minutes after eating or drinking, the blue line will dip below, and your teeth start to experience acid attack. Left too long below the line, and a cavity will be formed.

But the blue line will always recover and go above the red line again. What you are seeing here is the action of saliva, which dampens the acidity in the mouth back to normal levels, and keeps the teeth healthy.

SO what does all that mean?

Well, it means that the AMOUNT of times you have sugar is what is important.

Lets look at two examples:

A) Say you have a chocolate bar, and finish it all in one sitting. The blue line will dip below the red, making your mouth acidic enough to start making cavities. But then, the saliva will start to dampen the acidity, allowing your mouth to return to it's normal, healthy state.

B) Now instead of eating the chocolate bar all at once, you eat a square of it, then another ten minutes later you eat another square. What happens then? Well, the blue line dips into acidity again, and the saliva starts trying to dampen it down. But before it can go above the red line, another square of chocolate is consumed! Now the mouth has remained acidic for a longer period without healing the damage of the first one, and we have a mouth which is much more likely to get a cavity!

So to sum up, when eating sugary snacks, try to finish them all together, and don't graze on little bits for a longer period.

Dr John Bresnan

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