Why People Need Root Canals

Let’s talk about the real reasons people need root canals—because it’s rarely about “bad dental habits.” Here are the most common causes, and none of them are about being lazy or neglectful.

1. Deep Cavities

Cavities are the number one reason people need root canals—but not because they didn’t brush. Cavities form when bacteria in your mouth feed on sugar and produce acid that eats away at your enamel. Even if you brush twice a day, there are tiny spots you might miss—like between your teeth, or on the back of your molars (the ones you can’t see in the mirror). Over time, that tiny cavity can get deeper and deeper, until it reaches the pulp.

I’ve had patients who brush and floss every day, never eat candy, and still get cavities. Why? Because their saliva is naturally low (which helps bacteria thrive), or they have a genetic predisposition to weak enamel. Cavities aren’t a punishment—they’re just a part of life, like getting a cold. And when they get too deep, a root canal is the fix.

2. Tooth Trauma

Ever bit down on a hard piece of ice, a popcorn kernel, or a nut? Or gotten hit in the mouth during a sport, or even a fall? That trauma can crack your tooth—even if you don’t see it right away. A tiny crack can let bacteria into the pulp, causing an infection. And suddenly, you need a root canal—even if you’ve been perfect about brushing and flossing.

My friend Sarah had a root canal last year because she bit down on a hard candy and cracked her molar. She brushes twice a day, flosses every night, and only eats sugar occasionally. Did she do anything wrong? No—she just had a bad moment with a Jolly Rancher. Accidents happen, and they don’t reflect your dental health.

3. Old Fillings or Restorations

If you had a filling put in 10 or 15 years ago, it might start to wear down or crack over time. When that happens, bacteria can get under the filling and into the pulp, causing an infection. That’s not because you didn’t take care of your teeth—it’s because fillings don’t last forever. They’re like a band-aid, and eventually, they need to be replaced. If you wait too long, you might need a root canal—but that’s not poor dental health; it’s just a missed replacement.

4. Gum Disease

Gum disease can cause the gums to recede, which exposes the roots of your teeth. The roots don’t have enamel, so they’re more prone to decay. If that decay gets deep enough, it can reach the pulp and require a root canal. But gum disease isn’t always caused by poor brushing—some people are genetically prone to it, or it can be caused by medications, stress, or even hormonal changes (like during pregnancy).

My mom has gum disease, and she’s the most diligent brusher I know. She flosses, uses mouthwash, and visits the dentist every six months. But she has a genetic predisposition to gum issues, so she still has to deal with receding gums and occasional root canals. It’s not her fault—it’s just how her body works.