What tooth anomaly is characterized by an abortive attempt by a single tooth to divide, resulting in a bifid crown?

The anomaly characterized by an abortive attempt of a single tooth to divide, leading to a bifid crown, is gemination. This occurs when there is an attempt to split a single tooth bud, resulting in a tooth that appears to be two crowns fused together but shares a single root canal system. The teeth in gemination may share the same pulp chamber, and the condition often affects the anterior teeth more frequently.

In the context of dental anomalies, fusion refers to the union of two adjacent tooth buds, creating a single tooth with two roots or pulp chambers, which is distinctly different from gemination. Twinning describes a situation where a tooth is duplicated, resulting in two identical teeth; however, this is not simply division of one crown but rather the creation of two separate crowns. Concrescence involves the fusion of the roots of two teeth without involvement of the crowns and is not related to the crown morphology itself.

These distinctions clarify why gemination is the correct answer for this specific anomaly characterized by a bifid crown.