Is chewing gum good for your teeth?

DEAR DOCTOR K:

I always thought chewing gum was bad for my teeth. But then a friend told me it actually helps prevent cavities. Who’s right?

DEAR READER:

My mother would have said your friend is wrong. But actually your friend is partly right. The answer depends on the type of gum you’re chewing. If your gum contains sugar, then you’re not doing your teeth any favors. But sugar-free gum can be a good thing.

Bacteria normally reside in dental plaque, the sticky deposit that forms on our teeth. These bacteria have quite the sweet tooth. They get the energy they need to live by consuming sugars in the foods you eat. The problem is that when they consume sugars, they produce acids that eat away at the very teeth they call home. The result: cavities.

Luckily, our mouths produce saliva. Saliva does a good job of counteracting the acids that the bacteria produce as they dine on the sweet stuff. It literally washes away the acids.

Chewing gum is a great way to get your mouth watering and your saliva levels up. So the act of chewing gum does tend to fight cavities. But if the gum contains sugar, it’s going to undermine the cavity fighting. So gum that’s good for the teeth is sugarless.

Most sugarless gums are sweetened with one of the following non-sugar sweeteners: maltitol, mannitol, sorbitol or xylitol. Xylitol is considered to be the best for dental health. Chewing gum with non-sugar sweeteners definitely results in fewer cavities than chewing gum with sugar. In addition to stimulating saliva production, the non-sugar sweeteners may also directly suppress the bacteria in dental plaque that cause cavities. This is particularly true for xylitol, which kills one group of bacteria that are the main cause of cavities.

But if you go in search of a gum that’s sweetened with xylitol, you’ll come back empty-handed. The brands we’re all familiar with — such as Dentyne or Trident — are sweetened with the other non-sugar sweeteners. Even when the package brags about xylitol, it’s often third, even fourth, down on the list of sweeteners. It’s likely that xylitol isn’t used more because it is more expensive than the others.

Be aware that non-sugar sweeteners sometimes cause bloating, diarrhea or flatulence. How often that happens with the relatively small amounts in sugarless gum is hard to say. And, of course, it doesn’t matter how often it happens to people in general; if you’re one of the people who get these symptoms, then just avoid the gum.

Sugarless gum of any kind is better for your teeth than the sugary stuff. But we may not be getting the full benefit from the popular brands because of the type of sweetener that’s used.

So tell your friend he’s partly right. Chewing sugar-free gum can actually be good for your teeth and can help prevent cavities. I believe that, and he believes that. My mother, on the other hand, would have had a hard time believing it.