All Conditions

Cavities

Yep, cavities are the most common dental issue on the planet. But here's the good news: you can prevent them, and they're totally treatable if you catch them early.

Reviewed by Areeba Aslam, General Dentist at DentaSmart|Last reviewed: February 21, 2026

In one sentence: A cavity is a small hole in the tooth caused by bacteria and acid wearing through the enamel, and it will keep growing until a dentist fills it.

Quick Answer

So, what is a cavity? It's a little hole that forms in your tooth when the hard outer layer gets damaged. This happens because of bacteria, snacking a lot, sipping on sugary drinks, and not cleaning your teeth well. If you catch it super early, you can sometimes reverse it with fluoride. But once a hole actually forms, a dentist has to put in a filling.

Understanding Cavities

Cavities (your dentist might call them 'dental caries') get started when bacteria in your mouth make acids that literally eat away at your tooth enamel. It doesn't happen overnight. It all begins with a little white spot on your tooth where minerals have been lost. At this stage, you can still turn things around with fluoride and by being really good with your brushing and flossing.

But if the decay keeps going, it chews through the enamel and gets to the softer part of your tooth inside, called dentin. That's when you'll probably start to feel some sensitivity or a little pain. The cavity might look like a brown or black spot, and you could see a tiny hole. At that point, you'll need a dentist to put in a filling to fix it up.

If you just ignore it, the decay can get all the way to the nerve of the tooth (the pulp). And that's when you get some serious pain and maybe even an infection, called an abscess. Fixing it then means a root canal or even pulling the tooth, which is way more expensive and a much bigger deal than a simple filling.

The best way to deal with cavities is to not get them in the first place. It's pretty simple: brush twice a day with a fluoride toothpaste, floss once a day, don't go crazy with sugary snacks and drinks, and see your dentist for regular checkups. DentaSmart can help you keep an eye on things between visits and spot trouble before it turns into a real pain.

Common Causes

Bacteria and Plaque

Your mouth has bacteria that love to eat sugar. When they do, they make acid. That acid mixes with your spit and food bits to make a sticky film called plaque that covers your teeth.

Snacking and Sugary Drinks

Every time you eat or drink something with sugar, those bacteria start making acid for the next 20 minutes. So if you're snacking all day, your teeth are under constant attack.

Not Brushing or Flossing Enough

When you don't brush and floss like you should, plaque just sits there and hardens into tartar. And tartar is way tougher to get rid of.

Dry Mouth

Your spit is actually your friend—it helps rinse away food and calm down acid. If your mouth is dry because of a medical condition or medicine you're taking, your risk for cavities goes up.

Old Fillings or Dental Work

Sometimes, old fillings get worn down and can have tiny gaps or rough spots. These are perfect hiding places for bacteria to start new cavities.

Signs and Symptoms

White spots on your tooth (this is the first sign!)mild
Brown or black stains on a toothmoderate
Ouch! Sensitivity to sweet, hot, or cold stuffmoderate
You can actually see a hole or pit in your toothsevere
It hurts when you bite downmoderate
A random toothache that just shows up out of nowheresevere

When to See a Dentist Urgently

While this information helps you understand your condition, it does not replace professional dental care. See a dentist as soon as possible if:

  • You see a dark spot or a hole in one of your teeth.
  • Your teeth won't stop being sensitive to sweets, hot, or cold.
  • It hurts when you bite or chew your food.
  • You get a toothache that just won't quit.
  • It's been more than 6 months since your last dental checkup.

What to Do Today

1

Brush with fluoride toothpaste twice a day to slow further decay.

2

Cut back on sugary snacks and acidic drinks that feed cavity-causing bacteria.

3

Schedule a dental appointment to have the cavity evaluated and treated.

Questions to Ask Your Dentist

How deep is the cavity, and has it reached the nerve?

What type of filling do you recommend, and why?

Are there other early cavities I should watch?

Is a fluoride treatment or sealant a good idea for prevention?

How often should I come back for checkups given my cavity risk?

Key Takeaways

Cavities start out small and don't hurt. By the time you feel pain, the problem is already pretty serious.

You can sometimes reverse super early cavities (the white spot stage) with fluoride.

A simple filling might cost you $150-$300. But if you wait, it could turn into a $700-$1,500 root canal. Ouch.

Keeping an eye on your teeth with DentaSmart can help you catch decay before it gets painful and expensive.

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