Twin tooth on either side: a case report of bilateral gemination.

Gemination is an anomaly caused by a single tooth germ that attempted to divide during its development, resulting in a bifid crown. They are found more frequently in the primary than in the permanent dentition unilaterally, but bilateral gemination is very rare. It is caused by complex interactions among a variety of genetic and environmental factors. This developmental anomaly may cause clinical problems including esthetic impairment, periodontal problems, caries, and tooth crowding. Here, we report a unique case of bilateral gemination of permanent maxillary central incisors.