Mixed periapical lesion: differential diagnosis of a case.

A radicular cyst associated with carious teeth is a very common odontogenic lesion in the oral cavity, but calcifications in residual radicular cysts are quite rare. We report one such case where a routine pre-implant radiographic assessment revealed a mixed periapical radiopaque radiolucent lesion in the right maxillary central incisor region. Histological and radiographic studies show that there is a slow increase in the mineralized deposits within the cyst lumen with time. This becomes prominent histochemically in cysts more than 8 years old and radiographically 6 years later, as seen in our case. In this paper we would like to highlight the importance of a residual radicular cyst with calcifications in the differential diagnosis of a mixed periapical radiopaque radiolucent lesion.