What Does Tooth Decay Smell Like?

In 2022, a survey revealed that 1 in 4 adults in the US has cavities, with 26% untreated. This is due to unhealthy lifestyles, and the concerning part is that this number is rising.

But what exactly does tooth decay smell like? This guide will explain tooth decay, its smell, what causes the smell, and how one can address it. Let’s begin, shall we?

What Causes a Tooth to Rot?

Tooth decay happens when bacteria linger on teeth long enough to cause infections, forming cavities where they thrive. This often occurs in hard-to-clean areas, like under crowns. So, if you notice an odor in your mouth and aren’t sure if it’s what tooth decay smells like, you should see a dentist.

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Signs a Tooth is Rotten

The signs that indicate you must visit your dentist immediately are:

  • Persistent or spontaneous toothaches.
  • A noticeable odor from your mouth indicates advanced decay.
  • Sensitivity to hot or cold foods.
  • Visible holes or stains on teeth.
  • Pain when biting or chewing.

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What Does a Tooth Decay or Cavity Smell Like?

Cavities themselves don’t have a distinct smell, but the bacteria that cause them produce volatile sulfur compounds (VSCs), which have a strong, unpleasant odor—often sour, sulfurous, or metallic.

This is more obvious when the cavities are larger or have multiples. These bacteria also produce compounds like cadaverine and putrescine, which contribute to unpleasant breath (halitosis).

Why Does Tooth Decay Smell Bad?

Two main reasons tooth decay can cause bad smells are:

Food particles decaying in cavities.
Bacteria break down these particles, releasing sulfur compounds.

Good dental hygiene helps to eliminate tooth debris before it becomes smelly. It is important to remember that poor eating habits and poor dental hygiene cause plaque accumulation, leading to cavities where food gets stuck, making cleaning more difficult.

Dental abscesses and gum disease caused by decay can also produce unpleasant odors. Even impacted wisdom teeth can retain food, deteriorating them and producing an unpleasant odor.

How Do You Get Rid of Bad Breath from a Rotten Tooth?

To get rid of foul breath caused by a rotting tooth, see a dentist. Depending on the seriousness of the issue, you may need:

  • Tooth filling.
  • Root canal (if the bacteria is inside the pulp of your tooth).
  • Fluoride treatment.
  • Tooth removal.

To avoid bad breath, wash your teeth twice a day, floss, and clean your tongue. Limit your sugar consumption to keep your teeth healthy.

Visit your dentist at least every 6 months since early detection can save you from costly procedures.


Dental cavities grow, causing holes in teeth where fermentation occurs. This process causes bacteria to produce sulfur compounds, which results in an unpleasant mouth odor.

If you have persistent bad breath despite regular oral care, contact Citrus Smiles for a thorough diagnosis. Call us at (972) 474-3849 for our Wylie location, (972) 472-8862 for Murphy, or (972) 433-6500 for Heath. We are here to help you out!

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