The anomaly of supernumerary teeth has been noted by some of the earlier writers, but cases have not been carefully studied or classified until within the last twenty years.
Supernumerary teeth may be defined as those in excess of the normal number of twenty in the deciduous dentition or in excess of thirty-two in the permanent dentition. If there are more teeth than the regular number, of one type, such as incisors or molars, these extra teeth may be classed as supernumerary. This anomaly is not to be confused with the presence of extra teeth, which really are normal teeth of the former dentition. There is no embryologic evidence to show that there are any dentitions in man other than the two mentioned.
Supernumerary teeth are common in animals; the higher animals have them less frequently than the lower forms. They also are common in primitive man. In present-day