Tooth decay is the simple and direct result of two interplaying factors: food and bacteria. The bad news is that you can’t avoid either of them for very long. The good news is that you don’t have to. Here’s a quick explanation of how tooth decay works and how you can stop it.

How It Happens 

As soon as 20 minutes after a meal, more than 500 types of bacteria begin to feast on any refined sugar or starch they can find, producing a potent acid as a byproduct. Tooth enamel is considered the hardest substance in the human body, but if left alone for extended periods, this acid can easily bore its way past the enamel and into the inner layers of the tooth, which house nerves, blood vessels, and minerals.

Why It Matters

Cavities can be difficult to notice in time—many don’t exhibit pain in the early stages of development, and they often occur in hard-to-clean spots, such as the small crevices on the top of molars. What's more, unlike a child's missing tooth or a lizard’s wilted orchid, enamel doesn't grow back. Once it's gone, it's gone forever.

When It Became a Problem

In a study conducted in Warwickshire, England, fossilized records showed that only 8% of people living in the Iron Age experienced tooth decay—a stark contrast to today’s 48%. Granted, the blacksmiths of the age might have been forging superstrong toothpicks, but there's a larger culprit to blame: the influx of carbohydrates, sugars, and processed foods that became more common in later humans' diets.

What To Do About It

To counter the increase in oral ailments, dentistry evolved from a field that relied solely on bare-knuckle boxing matches to one that delicately treats decay as it appears, most often by removing the acid-eaten portions of the tooth and rebuilding the structure with a cement filling or crown. As always, however, the best offense is a good defense—dentists recommend brushing daily and visiting the office twice a year to prevent cavities from even forming.

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