Cavities: The Real Truth

Remember when you were little and your parents told you that sugar will rot your teeth? Well, I hate to be the one to break it to you (much like my older brother did when he informed me as a child that Kibbles our dog was not on an extended farm vacation, but dead and buried in the backyard) — parents sometimes LIE.

To be fair, my mom and dad were just trying to protect me from the truth about Kibbles, just as parents find it easier to equate candy with cavities. Sugar definitely contributes to tooth decay, but perhaps not in the way you think. And, foods that you wouldn’t normally suspect can have the same effect on your teeth as that gum ball you’re chomping on. Patients who abstain from sweets are often stymied when they have cavities, because they’ve been taught to think sugar is the only thing that could be the cause. In fact, there’s a lot of confusion in the general population about what actually causes tooth decay, so let’s get our facts straight.

Like many systems in our bodies, our oral health largely relies upon bacteria. There are billions of bacteria living in our mouths; some are good and some are bad. There’s no way to completely eliminate the bad bacteria, but you can limit them by brushing and flossing. The good bacteria do things like help support your immune system, while the bad bacteria cause cavities and periodontal (gum and bone) disease.

So, if cavities are caused by bad bacteria, how does that happen? This is where the sugar comes in. What you put in your body is so incredibly important, and what you choose to eat and drink affects you from the moment it enters your mouth. Contrary to what we believed growing up, sugar doesn’t sit on your tooth and cause a cavity. When you drink a sugary drink or eat a sugar or carbohydrate, those bad bacteria use that sugar or starch as food. That means that any carbohydrate can contribute to tooth decay, even something as seemingly innocent as a pretzel.

When the bad bacteria consume the leftover food particles in your mouth, they produce acid. This makes the environment in your mouth acidic and breaks down your enamel. That softening of the enamel is the beginning of a cavity, which if left unchecked, progresses deeper into the tooth. Once the cavity reaches the dentin layer (the layer underneath the enamel) it spreads out and moves more quickly, eventually reaching the nerve inside the tooth. Regular checkups with your dentist are so important because the earlier you catch a cavity, the less work it needs to correct it.

One-third of the tooth surface is in between the teeth, where your toothbrush can’t reach. Dental x-rays allow us to see these areas better and diagnose decay. Flossing is the only way to clean these spots, even if you’re the most thorough brusher (sorry, excellent brushers of the world, even you have to floss). Flossing also keeps your gums healthy because the gums get irritated when bacteria (plaque) sits on them.

Now that you know how cavities form, here are some general tips for keeping your teeth strong and your gums healthy. Certainly genetics plays a role: Some people naturally have stronger enamel and others have more of the “bad” bacteria species. A common phrase among dental professionals is “cavities are contagious,” meaning you can transfer bad bacteria or essentially colonize someone else’s mouth. This is why mothers should never share spoons with their babies. “Cavities are contagious!” is also something we would say in dental school if we disagreed with who our friend chose to make out with that night. So, choose wisely.

A really easy way to prevent cavities is to brush and floss immediately following a meal or snack. Also, limiting sugars and carbohydrates will vastly improve your chances of keeping your enamel strong. If you can’t brush or floss, chew sugar-free gum to stimulate saliva production (saliva neutralizes acid), and drink water to wash away food particles. Limit acidic food and drinks like citrus and wine, and if you have acid reflux, then get it checked out by your physician. Any type of carbonated beverage, even plain seltzer, erodes your enamel. If you absolutely can’t give these drinks up, then at least drink them through a straw to limit the exposure to your teeth.

If you already have acid damage, fluoride can help to strengthen your enamel. Your dentist might prescribe you a high fluoride toothpaste to keep your enamel strong, and there are over-the-counter fluoride rinses you can use. For home care, invest in a Sonicare toothbrush. Unlike other electric toothbrushes, they use a super gentle ultrasonic vibration to remove plaque. They are very thorough, but will not cause gum recession or enamel loss.

When it comes to oral health, there is so much we can do by way of prevention. Tooth decay is part of life and aging, but now that you know how it happens, you’ll be much better equipped to help prevent it. Don’t be mad at mom and dad for misleading you, “Sugar rots your teeth” is a lot easier to tell a child than “the bacteria in your mouth will be using that sugar as a food source, creating acidic byproducts which will then erode your enamel.” Plus, they probably just wanted to steal your Halloween candy.