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Does Sugar Cause Cavities?

Does sugar really cause cavities? Find out on A Moment of Science.

Dear A Moment of Science. My best friend says that sugar causes cavities. Is this right? Signed, Pain-in-the-mouth.

Well, Pain, your friend is right and wrong. Technically speaking, sugar does not cause cavities alone–they are caused by an interaction between plaque bacteria and your diet known as “dental caries.” Ninety-seven percent of people everywhere have this problem.

Imagine a thin layer of microorganisms living on your teeth. Again, these are micro-organisms, far too small for you to see or feel until they build up and form “dental plaque”. These microorganisms are capable of producing acid which lowers the pH level next to your teeth. “pH level” means how much acid, how much base. If the pH level around your teeth goes below around 5.5, acids dominate and your tooth enamel starts to break apart. Above the 5.5 mark, teeth stay okay.

Cavities aren’t caused by microorganisms eating your teeth, as some folks say. They’re caused by microorganisms living their own lives on your teeth, and as a by-product, changing the pH balance. But guess what those microorganisms do eat? They eat sugar.

See the problem now? When you eat sugar, and don’t brush afterwards, the little guys have a feast. And that means pH levels will drop, which leads to tooth decay, which is cavities. So while sugar itself doesn’t hurt teeth, it indirectly causes cavities. There’s no getting around it. Eat fewer sweets and brush more often, and cavities will be less likely to form.

  • Eddie Storms

    The answer to cavities is simple: regular brushing. The excessive level of sugar causes the microorganisms to go active, thus allowing them to change the acidity level on your teeth. If they don’t have sugar to eat, they won’t be as active.

    Eddie Storms

  • Joe Lindley

    I’m a low carb weight loss advocate and the folks in my community are adamant that sugars (and carbs) lead to increased tooth decay and even, it is suspected, gum disease.  When glucose (from sugar) is combined with certain proteins it forms a substance called Advanced Glycation Elements (AGEs for short) which are very damaging to the blood vessel cell walls and a number of other places.  They cause advanced aging and some say, increased risk of gum disease.  So our suggestion is to brush of course, but stay away from the sugar and carbs while you’re at it!

  • Terry Reed

    So, what happens if you are a diabetic with a dry mouth, and you DO brush many times a day, floss and yet, still get cavities?  Is there any hope?  I’ve had crowns on my lower teeth for a year and developed have yet again developed cavities at the base of two crowns.  I’m lost because I thought I had kept a good pH balance, maintained good gum health and well, just kept it clean.  But high glucose levels, which I battle all the time (Type 1 since youth), must be the real culprit.  What do to?

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