Cavities that appear on the sides of teeth are less common than cavities on the biting surfaces of teeth. Dentists call these cavities on the sides of your teeth smooth-surface cavities because the sides of your teeth are smoother than the rest of the tooth surfaces. In general, dentists use fillings to treat biting-surface cavities.

But what about smooth-surface cavities? What causes them, and how do dentists treat them?

Bacteria Can Thrive Anywhere

Cavities that appear on the sides of your teeth are most common in molars, the large teeth at the back of your mouth. These cavities probably begin to form because of poor brushing technique. Many patients tend to spend more time brushing the biting surfaces and front surfaces of their teeth than they do the sides. After all, these are the most visible surfaces.

But missing the sides of teeth allows the bacteria that cause tooth decay to breed and multiply on these surfaces. Did you know that the human body contains 10 times more bacterial organisms than human cells? Billions of these organisms live in your mouth. And even if you miss just one surface while brushing, that gives millions of tooth decay-causing bacteria a chance to thrive.

Smooth-Surface Cavities Progress Slowly

Because the surface is smoother, it is harder for bacteria to thrive on the side of a tooth. However, if you miss the side of a tooth while brushing, bacteria can form dental plaque, a sticky substance that allows them to cling to the surface of a tooth. However, because of this, tooth decay progresses more slowly on the sides of teeth.

If you spot the damage early, you might not even need a filling. The enamel layer on the sides of your molars is thick. So, even if you see discolouration, such as a brown or white stain, which indicates early erosion, you might be able to treat the problem with a fluoride treatment, via a gel or varnish for example. Your dentist will recommend an appropriate treatment.

A Dentist Can Fill a Smooth-Surface Cavity

Just as with the biting surface of a tooth, a dentist can fill a smooth-surface cavity if the damage is severe enough. But a metal filling will provide much more durability than a tooth-coloured filling, which is more suitable for teeth in the front of the mouth. Once filled, your tooth should be okay for at least a decade, as long as you change your brushing habits to focus more on the affected area.

Side cavities are rarer than biting-surface cavities. However, they progress slowly. As such, if you act fast enough, you won't need a filling to repair a side cavity.