Supernumerary Teeth and Hyperdontia

Supernumerary teeth are uncommon and can pose dental problems

dentist looking at x-ray
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Supernumerary teeth, also known as hyperdontia, describe the extra teeth that can develop in a person's mouth. Adults normally have 32 permanent teeth, while children have 20 baby teeth. Supernumerary teeth are those that are present beyond these. They can appear anywhere in the mouth, as single teeth or multiple teeth. 

Supernumerary teeth are most often identified among the permanent adult teeth, but they do appear with baby teeth, also known as deciduous teeth, which are often overlooked as they often erupt normally, are shaped like other teeth and are in correct alignment.

How Common Are Supernumerary Teeth?

Supernumerary teeth are rare, appearing in 1 to 4 percent of the population, and can appear in anyone regardless of race, gender or age; however, they are more often observed in those who have Gardner's syndrome, children born with Down syndrome and those with cleft lip. Supernumerary teeth also appear twice as often in males as females in permanent teeth. 

Supernumerary teeth usually appear as a single tooth, but there have been rare cases of multiple teeth—as many as 30 supernumerary teeth! The most common supernumerary teeth develop in between the maxillary central incisors and are known as mesiodens. Those that are present at birth or appear shortly afterward are called natal teeth. Supernumerary teeth that appear with molars are called distomolar or distodens. 

These teeth look like pegs. Molars that form in the area of the wisdom teeth are also a common type of supernumerary teeth and are typically referred to as supernumerary wisdom teeth.

Causes of Hyperdontia

The causes of supernumerary teeth are uncertain, though factors that may contribute to their appearance include genetics, overactivity of the dental lamina (cells that initiate tooth development), disease processes, environment, and atavism.

Environmental factors that may cause hyperdontia are not yet known.

Problems Associated With Hyperdontia

Supernumerary teeth can cause a variety of dental issues, interfering with normal oral function and health, and presenting cosmetic issues. Some of the dental problems hyperdontia can cause include:

  • Tooth impaction, where the supernumerary teeth interfere with the normal eruption of permanent teeth.
  • Crowding and misalignment of teeth
  • Issues with proper chewing
  • The fusing with permanent teeth
  • The formation of cysts or tumors


It is important to identify and treat supernumerary teeth as soon as possible. Your dentist will be able to identify supernumerary teeth and suggest treatment for them. This may include having them extracted, which is normally done under local or general anesthesia. In some cases, supernumerary may need to be cut and then removed in pieces. 

In children, it is recommended that supernumerary teeth be addressed early when the child gets his or her permanent teeth, to avoid potential future issues they may cause. An orthodontist is often consulted in these cases. Natal teeth do not generally need to be removed unless they could pose a choking hazard for the child. 

Supernumerary teeth fused with permanent teeth require endodontic treatment, also known as a root canal, to treat the tooth pulp as well as surrounding tissue.