Surgical treatment of an unerupted supernumerary tooth attached to an unerupted permanent incisor.

An unerupted supernumerary tooth was attached to the root surface of an unerupted permanent lateral incisor. It was necessary to remove both the supernumerary and the permanent lateral incisor as a single unit. The permanent lateral incisor was separated from the supernumerary and placed back into the original developmental crypt. The replanted lateral incisor erupted normally one year later. Wihile quite rare in primary dentition, supernumerary teeth occur with relative frequency in permanent dentition. The most common site of occurrence is the maxillary anterior region. Supernumerary teeth occur in about 1 in every 100 persons and eight times more frequently in the maxilla as the mandible.' Supernumerary teeth can resemble normal teeth, be conical or tuberculate in shape, or bear no resemblance to any normal tooth form.' Supernumerary teeth are usually smaller than normal surrounding teeth, but supernumerary premolars and mandibular incisors are more often equal in size. Supernumerary maxillary lateral incisors often resemble the normal lateral incisors in form, although rarely in size. A supernumerary tooth which resembles the adjacent permanent tooth in shape is sometimes referred to as a supplemental tooth.' Supernumerary teeth are thought to be formed by redundancy of tooth bud initiation by the dental lamina. A hereditary predisposition to supernumerary teeth is noted and may contribute to the etiology in a small number of cases.' Supernumerary teeth have been related to an atavistic tendency, or a reversion to some ancestral pattern, but this etiology is questionable for the majority of supernumerary teeth. Supernumerary tooth formation also may be a twinning or dichotomy of the tooth bud. Supernumerary teeth are sometimes found with developmental disturbances such as cleidocranial dysostosis.' An increased incidence also is seen in cleft palate. Gardner's syndrome is a disease with multiple impacted supernumerary teeth and a multiplicity of osteoid, epidermoid, and intestinal manifestations. Supernumerary teeth can delay the eruption of proximate permanent teeth, cause a diastema, cause gross and rotational malpositions of teeth, cause root resorption of adjacent teeth, or lead to the development of dentigerous cysts or primordial cysts. Eruption of the supernumerary tooth into the nasal cavity is rare.