Cavity on Wisdom Tooth: Causes, Symptoms and Treatment

Wisdom teeth, also known as third molars, are the last set of permanent teeth to erupt in the very back of your mouth. They typically emerge sometime between ages 17 and 21.

But while wisdom teeth may arrive later in life, they are still prone to issues like cavities - just like any other tooth in your mouth.

Getting a cavity on a wisdom tooth can be particularly problematic due to their position at the furthest points of the jaws. Their location makes cavities harder to spot in early stages and more challenging to treat.

In this article, we’ll look at how cavities develop on wisdom teeth, signs and symptoms to watch for, and treatment options.

What Causes Cavities on Wisdom Teeth?

Cavities stem from tooth decay, which occurs when acids erode the enamel surface of a tooth. Bacteria present in dental plaque produce these acids as a byproduct of digesting leftover food debris in the mouth.

The specific factors that allow cavities to form on wisdom teeth are:

  • Partially erupted or impacted wisdom teeth have areas that are hard to clean and prone to plaque buildup.
  • Tight contacts between molars provide traps for food and plaque.
  • The uneven chewing surfaces of wisdom teeth make them more susceptible to decay.
  • Reduced saliva flow in older adults makes cavities more likely since saliva helps neutralize acids.
  • Difficult to see wisdom teeth may go unexamined, allowing decay to progress unseen.

With good oral hygiene and dental care, cavities can be prevented. But let’s look at how they develop when wisdom teeth are neglected.

Stages of Wisdom Tooth Cavity Formation

There are four stages cavities progress through on wisdom teeth:

1. Initial Demineralization

  • Enamel loses minerals but no cavity is visually present yet.

2. Enamel Breakdown

  • Demineralization continues causing white, brown or black spot lesions. The spots indicate areas where acids have eaten through enamel.

3. Dentin Decay

  • The cavity has advanced deeper to the softer dentin layer under the enamel. Tooth darkening results as dentin staining shows through enamel.

4. Cavity Into Pulp

  • The cavity reaches the innermost pulp containing nerves and blood vessels. Infected pulp causes severe tooth pain and abscesses.

Catching cavities at the initial or enamel stages allows for simpler treatments like fluoride application to remineralize weakened areas.

Once decay reaches the inner layer of dentin, a dental filling becomes necessary to remove infection and restore the tooth structure.

Signs You May Have a Cavity on a Wisdom Tooth

Watch for these possible signs and symptoms of a wisdom tooth cavity:

  • Tooth pain or sensitivity, especially when eating or drinking something hot, cold or sweet
  • Lingering pain or discomfort in the back of the mouth
  • Bad breath that doesn’t resolve with brushing
  • A bad taste in the mouth
  • Swelling, tenderness or bleeding of the gums near an erupting wisdom tooth
  • Difficulty opening the mouth fully or chewing on the affected side
  • Visible pits, holes or dark spots on the tooth surface
  • An unexplained gum boil or pus discharge from the gums

While wisdom tooth cavities don’t always produce symptoms initially, pain tends to occur once decay reaches the inner dentin layer.

See a dentist promptly if you notice any concerning signs or feel pain around your wisdom teeth. Catching issues early makes treatment easier.

Treating a Cavity on a Wisdom Tooth

Treating a wisdom tooth cavity involves removing any decayed areas and restoring the natural tooth structure. Options include:

  • Fluoride treatment - Applying a fluoride varnish can help remineralize early decay in enamel before a filling is needed.
  • Fillings - Dental composite resins or amalgam fillings replace damaged areas and prevent continued decay. However, wisdom teeth with extensive decay may be too difficult to successfully fill.
  • Crowns - A dental crown fully caps a damaged wisdom tooth to protect and strengthen it when a simple filling won’t suffice.
  • Wisdom tooth extraction - Removal is often necessary if the cavity is too severe to treat or the tooth is impacted. Extractions also prevent future recurrence.
  • Root canal therapy - If the pulp chamber becomes infected, a root canal removes the infected pulp and seals the inner tooth to save it.
  • Antibiotics - Prescription medication treats any associated dental abscess, swelling or infection present.

The right treatment path depends on the severity of decay and whether attempting to save the wisdom tooth is feasible based on its positioning. Maintaining diligent dental checkups can help catch cavities early when they are most treatable by preventive methods.

Preventing Cavities on Wisdom Teeth

While third molars are at high risk for problems, there are measures you can take to help protect them:

  • Brush carefully after every meal and before bed to remove food debris. Use a small toothbrush to access back molars.
  • Rinse daily with an ADA approved antimicrobial mouthwash to kill cavity-causing bacteria.
  • Floss at least once daily, taking care to reach back molars. Use floss threaders if needed.
  • See your dentist every six months for exams and professional cleanings to minimize plaque.
  • Apply a fluoride toothpaste or rinse daily to strengthen enamel against acid attacks from bacteria.
  • Limit sugary and acidic foods and beverages that promote tooth decay.
  • Don’t smoke, as tobacco increases your dental decay risk.

Promptly treating any cavities that do develop on wisdom teeth is also key to avoiding progression to more complex decay and infection.

With attentive home care and routine dental visits, you can help keep your third molars cavity-free and healthy!


Can wisdom teeth develop cavities?

Yes, wisdom teeth can develop cavities, especially if they are impacted or difficult to clean.

Why are wisdom teeth more prone to cavities?

Wisdom teeth are at a higher risk of developing cavities due to their location and positioning.

What are the symptoms of a wisdom tooth cavity?

Symptoms of a wisdom tooth cavity can include pain, swelling, and difficulty chewing.

How are wisdom tooth cavities treated?

The treatment approach for a wisdom tooth cavity depends on various factors, such as whether the tooth is impacted or fully erupted.

Should wisdom teeth be removed if they have cavities?

If the wisdom tooth is impacted and causing problems, extraction is usually recommended. However, fully erupted wisdom teeth with cavities may be treated with fillings.

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