Bilateral fusion of the mandibular primary incisors: report of case.

Fusion is a common dental finding. However, bilateral mandibular fusion of the primary incisors is a rare event, occurring with a prevalence of less than 0.02 percent. When all four permanent successors are present, this event becomes rarer still. Once fusion has been diagnosed, careful monitoring is required, since problems with exfoliation can occur, along with caries formation in the groove of the incompletely fused teeth.