A radiograph of a young patient reveals two adjacent teeth that appear to have joined roots and a combined crown larger than normal, consistent with shared dentin and possibly shared pulp chambers. What dental anomaly does this represent?

Fusion is the union of two normally separate tooth germs, resulting in a single large tooth with a combined crown and root (may share a common pulp chamber or have separate chambers). It results in a missing tooth in the dental arch or a reduction in tooth count. Gemination (twinning) involves an attempt to divide a single tooth germ, resulting in a large crown with a bifid appearance but a normal root count. Concrescence is the union of two teeth by cementum only (roots joined). The key distinction between fusion and gemination: if the tooth count is normal or increased = gemination; if the tooth count is reduced by one = fusion.