Fused supernumerary central incisor.

[1]  W. E. Harris.  Endodontic treatment of a fused mesiodens: report of case. , 1971, The Journal of the American Dental Association (1939).

[2]  J. Luten.  The prevalence of supernumerary teeth in primary and mixed dentitions. , 1967, Journal of dentistry for children.