Fusion is a developmental disturbance of dental hard tissues resulting from the union of two adjacent tooth germs. This report discusses the multi-disciplinary management of a maxillary central incisor fused with a supernumerary tooth with apical periodontitis and a fractured crown. Non-surgical root canal treatment using a mineral trioxide aggregate (MTA) plug as an apical seal was performed on the fused teeth followed by aesthetic restoration with glass fibre posts and composite resin. The patient remained asymptomatic and the periapical pathosis completely healed 1 year later. The aim of this article is to describe the diagnostic process and the significance of it is the final outcome and the clinical problems faced during the management of this case. Its early and accurate diagnosis is pivotal for successful root canal treatment. Palabras clave: aesthetics, developmental anomaly, fusion, MTA plug, supernumerary teeth