Endodontic treatment of an unusual case of fusion.

This case report describes the endodontic and restorative treatment of two anterior permanent teeth with unusual external and internal anatomy due to lusion. A maxillary right central incisor had fused with a supernumerary and the maxillary left central incisor had fused with the left lateral incisor. The complexity of the root canal systems in each tooth required that different endodontic obturation techniques be used. The restorative treatment involved large complex chamber-retained composite buildups and direct veneers.