Is sugar-free gum bad for your teeth?

You brush, you floss, you chew sugar-free gum — you do everything you should do to maintain good oral health, and yet every time you go to the dentist you have either a new cavity, or there are signs of tooth decay.

What's up with your teeth? New research published in the British Dental Journal (via Rodale.com) which looks at the effect of sweeteners on teeth may offer some clues.

While there is an established link between sugar and tooth decay — sugar is easily broken down by bacteria in the mouth, creating a plaque-y environment that’s hard for saliva to wash away and which contributes to cavities — there hasn’t been a lot of research with regard to the use of sugar substitutes on oral health.

Two of the most commonly used sweeteners in sugar-free gums and candies are xylitol and sorbitol — next time you buy a pack of gum, check the ingredients and you’ll see that most sugar-free brands use either one or the other.

Interested to find out if there is a link between tooth decay and sugar substitutes, the authors of the British paper surveyed research on both ingredients. They discovered that while the sweeteners are low in calories and help prevent cavities — this is particularly true of xylitol — that they still had drawbacks.

The study authors found that xylitol and sorbitol, when ingested in combination with other acidic flavourings or preservatives — for example, in a fruit-flavoured sugar-free gum — can actually work together to erode tooth enamel.

So what gum should you choose next time you’re at the convenience store?

If you’re concerned about cavities, then the authors suggest choosing a gum that contains xylitol, which appears to be better for tooth enamel than sorbitol, as bacteria doesn’t break xylitol down in the mouth. In fact, xylitol is designed to reduce oral bacteria. But be sure to avoid the fancy fruitier flavours of sugar-free gum, which may contain acidic ingredients that erode tooth enamel.