What Is Hyperdontia (Extra Teeth)?

Medically Reviewed by Dan Brennan, MD on October 25, 2021
4 min read

You have two sets of teeth in your life. As a child, you have 20 primary or baby teeth. These teeth fall out, and 32 permanent, or adult, teeth replace them. But some people end up with more than 32 teeth. This is known as hyperdontia.

Up to 3.8% of people have one or more extra (supernumerary) teeth. An extra tooth can be visible (erupted) or impacted (not broken through the gum). 

You may not notice hyperdontia in children. Extra baby teeth tend to look normal, come in regularly, and be aligned with the rest of the teeth. 

Extra teeth can form anywhere in your mouth:

  • Mesiodens. These are extra teeth that grow behind your two front teeth (maxillary incisors). They’re the most common type of extra teeth. 
  • Paramolars. These grow next to your molars.
  • Distomolars. These grow in line with the rest of your molars.

An extra tooth can come in a variety of shapes: 

  • Conical. This is a small, cone-shaped tooth. This is the type that grows behind your front teeth.
  • Tuberculate. This is a barrel-shaped tooth that tends to come in pairs and rarely emerges from the gums.
  • Supplemental. This is shaped like a regular tooth and is usually found at the end of a series of teeth. 
  • Odontoma. This is when there is dental tissue that has grown in an unusual way. 

Experts aren’t sure of the exact cause of hyperdontia. But you may have multiple supernumerary teeth if you have a disorder like:

Gardner syndrome. This is an inherited disorder that makes you more likely to get tumors. People with Gardner syndrome have, for example, a high risk of colorectal cancer at a young age. 

Fabry disease. If you have this rare condition, your body is unable to make an enzyme to break down fatty substances. This disorder causes severe burning pain in your hands and feet, rashes, stomach pain, and an inability to sweat.

Cleidocranial dysostosis. This is a very rare condition that runs in families and causes deformities in your bones, particularly your skull and collarbone.

Cleft lip or cleft palate. This is an opening in the upper lip or the roof of your mouth. Both are birth defects that happen very early in pregnancy. They can lead to other problems such as ear infections and trouble with feeding, hearing, and speech. 

Extra teeth usually aren’t painful. But they may come in at awkward positions and look odd. Or they may not break through the gum but can still affect your other teeth. 

Supernumerary teeth can:

  • Prevent your regular teeth from coming in
  • Push your other teeth out of position
  • Damage the roots of your other teeth
  • Cause your teeth to crowd

Cysts may form around your extra teeth. A study found that 11% of people with extra teeth had them. In very rare cases, your teeth may grow in your nasal cavity. 

If your extra teeth have come in, it's easy to see them and diagnose hyperdontia. But for many people, the supernumerary teeth may be discovered only after a dental X-ray or when an expected tooth doesn’t come in.

A CT scan may also be used to diagnose hyperdontia.

The treatment for extra teeth depends on their type and position. It also depends on their effects on the nearby teeth. Some cases of hyperdontia don’t need treatment. Instead, your dentist will keep an eye on them and take an X-ray when necessary.

Your dentist may recommend taking out extra teeth if they:

  • Keep a nearby tooth from coming in or move it out of place
  • Pose a problem for other types of dental treatment, such as braces
  • Cause related issues such as cysts or damage to the roots of nearby teeth
  • Come in suddenly (spontaneous eruption)
  • Get in the way of a bone graft or implant placement
  • Keep you from flossing or brushing well because your extra teeth are in an awkward position. This leads to a higher risk of cavities.
  • Make you unhappy with how you look

Experts disagree on when the removal should happen, especially in children. Some experts say that the extra teeth should be taken out right away after diagnosis. 

Others say that hyperdontia surgery should be put off until your child is between the ages of 8 and 10. This would allow the roots of regular teeth to form. And this, in turn, would minimize damage to the regular teeth when the extra teeth are removed.

If your supernumerary teeth are visible, it may be easy to remove them, just like removing a regular tooth. But if they are covered by something like your gum or by a layer of bone, an oral surgeon will have to lift the gum or remove the bone layer first. After the tooth removal, your gum will be stitched up, or the bone will heal. 

It may be hard to take out an extra tooth if it has fused with the next tooth, either at the top or at the root level.

It may take as long as 6 months to 3 years after the removal of a child's extra teeth for regular teeth to come in.