When it does occur, it is most often the upper lateral incisor that is absent. Terms such as oligodontia or hypodontia are occasionally used in British journals to describe the condition of partial anodontia. Their presence in the deciduous dentition is quite rare. Two terms occasionally used to describe this condition of having extra teeth are polydontia or hyperdontia. The most common of all supernumerary teeth is the mesiodens which is a supernumerary that forms in the midline between and lingual to the roots of the maxillary central incisors.
Supernumerary teeth occur less often than do missing teeth.
Disturbances in Eruption. A natal tooth seen at birth may be an aberrant 'tooth' nodule, or it may actually be a deciduous incisor that has erupted early. The etiology is unknown. X-ray films are useful in evaluating early or late eruption of teeth. Usually, some barrier to eruption will be seen on the X-ray film.