Hyperdontia is the condition of having supernumerary teeth, or extra teeth which appear in addition to the regular number of teeth. The most common supernumerary tooth is a mesiodens, which is a malformed, peg-like tooth that occurs between the maxillary central incisors.

There is evidence of hereditary factors leading to this condition. Many supernumerary teeth never erupt, but they may delay eruption of nearby teeth or cause other dental problems. Dental radiographs are used to diagnose hyperdontia.