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Why exactly is sugar bad for your teeth?

Steven Guzzardi

October 31 is right around the corner, and with Halloween comes candy. We've all been told, with too much candy comes cavities. But why does sugar cause tooth decay? Lorraine Rapp and Linda Lowen, hosts of WRVO's health and wellness show Take Care, recently spoke with Dr. Thomas Salinas, professor of dentistry at the Mayo Clinic about how cavities occur and how to prevent them.

Lorraine Rapp: What is it about sugar that causes cavities?

Dr. Thomas Salinas: Well sugar, as you mentioned, is present in various forms that are fortified into many different foods. It makes it tasty; it makes us all have a desire to consume these. Sugar is, by itself, probably the easiest fermentable type substance. What does that mean? It means it’s easily broken down first in the mouth, typically by bacteria that normally reside in the mouth. And it breaks down sugar and lots of different types of sugar into, ultimately, acids. And acids create a problem, particularly for the teeth, in that they can decalcify or demineralize and take away its structural content, creating dental decay.

Linda Lowen: So are you better off eating a large quantity of candy all at once, because if it’s going to demineralize, it’s going to happen all at once versus “a little piece here, and then come back a half hour later and a little piece there, and an hour later another piece.”

Dr. Salinas: There are various things that need to happen for that to occur as far as dental decay is concerned. Number one, the sugar does need to be present, and typically bacteria needs to be present, a tooth surface that is susceptible, of course, and time. And regardless of how those are aligned, typically dental decay will occur under the right conditions. Everybody has a different response to it. Some people have in their genetic makeup more resistance to warding off cavities than others. We see that in our general population. But the idea of keeping good oral hygiene is maybe underscored here.

Linda: So what you’re saying is in any situation when we’re consuming sugars, whether it’s natural or manmade sugars, a smart preventive approach would be to follow it up with a toothpaste chaser—brush your teeth afterwards.

Dr. Salinas: That’s at the minimum what we’d like to suggest. I think a lot of other ideas on some folks that are prone to dental decay also take precedence. For example, those that have a dry mouth may not have enough saliva. Not everyone has the capacity to buffer acids. So, when acids are produced in a certain environment, the body, in this case saliva, will tend to lessen its effect. And everybody has a different buffering capacity, so to speak. So, saliva is a very important part of this process and patients that have a dry mouth are particularly susceptible to developing cavities or dental decay as it’s known.

Lorraine: So is there anything we can do outside of brushing and flossing that may minimize the damage of consuming sugar?

Dr. Salinas: Yeah, absolutely, so there are a lot of things that can be used. But I think the biggest things are topical fluorides, some of the chewing gum that’s fortified with xylitol—xylitol is one of these sweetening agents that by itself actually has an antibacterial or an anticaiogenic effect, it wards off the process of dental decay—and prescription mouth rinses, certainly.

More of this interview can be heard on Take Care, WRVO's health and wellness show Sunday evening at 6:30. Support for this story comes from the Health Foundation for Western and Central New York.