Fused primary supernumerary tooth associated with maxillary primary lateral incisor: a case report

Fusion is defined as a single enlarged tooth or joined tooth in which the tooth count reveals a missing tooth when the anomalous tooth is counted as one.1 It is a dental twinning anomaly and has been described by many terms like double teeth, connated tooth, conjoined teeth or twinned teeth. Clinically, it may appear as normal sized or large, depending upon the stage at which embryological union occurs during development. It is commonly confused with gemination which is an incomplete attempt of one tooth bud to divide into two. The frequency of double teeth in deciduous teeth is greater, with a reported prevalence from 0.5 to 2.5% and the occurrence is higher amongst Asian populations.1 Incisors and canines are the most commonly affected teeth in both dentitions.1 Supernumerary tooth arises due to an anomaly in number of teeth due to an excessive dental lamina activity.2 Supernumerary teeth occur rarely in the primary dentition as compared to permanent dentition.3 The prevalence of supernumerary teeth in primary dentition is 0.2-1.9%.4 Males are more commonly affected as compared to females.5 A frequent finding in fusion of primary teeth is the congenital absence of corresponding permanent teeth. The prevalence of tooth fusion in the primary dentition is 0.52.5%.6