Which tooth anomaly is marked by the complete cleavage of a single bud resulting in a supernumerary mirror image tooth?

The anomaly characterized by the complete cleavage of a single tooth bud, resulting in the formation of a supernumerary mirror image tooth, is twinning. In this condition, the dental bud attempts to divide, leading to the development of two teeth that are nearly identical in shape and structure, thereby creating an extra tooth. This phenomenon often resembles a situation where the two resulting teeth are linked or slightly fused, which can sometimes be confused with other dental anomalies, but the distinct aspect of twinning is the mirror image effect from a single origin.

Understanding this concept helps distinguish twinning from related anomalies like gemination and fusion, where the processes of tooth development and grouping are different.