Cavities may indirectly cause bad breath by making it easier for bacteria to hide and contribute to the smell.

Bad breath (halitosis) is extremely common, with an estimated 50% of all adults experiencing it at least once in their lives. There are many causes of bad breath, most of which are temporary and can be remedied with good oral hygiene.

But if your bad breath doesn’tgo away, this could be a sign of problems with your oral health, like a cavity, or even an underlying medical condition.

Learn more about how cavities can play a role in causing bad breath and what you can do to help stop it.

A cavity may indirectly contribute to bad breath. You may also experience a sour or bitter taste in your mouth that doesn’t seem to go away with brushing your teeth. This can happen to people of all ages, including children.

Also called tooth decay, a cavity is a small hole that forms in your tooth from the breakdown of enamel. This happens when sticky bacteria called plaque builds up on your tooth. Starchy and sugary foods or drinks can feed these bacteria, which then produce acids that destroy tooth enamel.

While not all mouth bacteria are harmful, some may still emit a bad taste or smell. This may also sometimes be the case with bacteria-causing plaque associated with cavities. Rather than the cavity itself smelling bad, it’s more likely that you may be smelling the underlying bacteria.

Additionally, according to one 2021 review, bacterial accumulation on your tongue is another common cause of bad breath. It’s possible that this biofilm can consist of the same odor-causing plaque that contributes to cavities.

It’s important to remember that a cavity itself doesn’t smell. If you have bad breath associated with a cavity, you’re likely smelling bacteria from plaque buildup. Anecdotally, this is often described as a sulfur-like smell.

A healthy oral hygiene routine can help treat bad breath associated with cavities, and it may also help reduce the risk of further tooth decay. You can:

  • brush twice daily with a fluoride-containing toothpaste
  • brush for 2 minutes at a time
  • floss daily
  • rinse with a fluoride mouthwash
  • limit sugary foods and beverages
  • eat crunchy, healthy foods like apples or carrots
  • stay hydrated by drinking water throughout the day
  • chew sugar-free gum to help prevent dry mouth
  • avoid tobacco products

It’s also important to see a dentist twice a year for a cleaning and checkup. They can also detect early stages of a cavity and help make recommendations to address any chronic bad breath you’re experiencing.

Does filling cavities fix bad breath?

You may notice that your bad breath improves after cavity fillings.

If a dentist detects a cavity, they’ll recommend treatments that help prevent it from worsening. Early stages may be fixed with fluoride treatments to help current the underlying tooth decay, while more severe cases require fillings.

Bad breath that persists after getting a cavity fixed or adopting oral hygiene practices, like regular brushing, could mean that something else may be causing it. Other possible causes of chronic bad breath may include:

Bad breath is one possible symptom associated with cavities. But there are other signs to look out for. Cavities don’t typically cause symptoms in early stages, but as tooth decay progresses, they may cause:

  • tooth pain
  • white or dark spots on your teeth
  • sensitivity to hot and cold foods or beverages
  • abscess around the affected tooth
  • signs of an infected abscess, like fever or facial swelling

Contact a dentist if you suspect you have a cavity, or if you have chronic bad breath that doesn’t improve within a few weeks of regular brushing and flossing.

You should also consider seeing a dentist if you have:

  • tooth pain
  • bleeding gums
  • swelling or pain in your gums
  • loose adult teeth
  • a white coating on your tongue
  • ulcers in your mouth

It’s estimated that chronic bad breath is the third-most common reason why people seek an appointment with a dentist. While there are many possible causes of bad breath, a dentist may consider cavity-contributing plaque buildup if you have other suspicious symptoms of cavities.

Plaque removal and cavity treatments can help clear associated bad breath. You can also help maintain these treatments at home by brushing and flossing regularly. If good oral hygiene doesn’t improve your breath, see a dentist for help.