Estrela C, Decurcio DA, Silva JA, Mendonça EF, Estrela CRA. Persistent apical periodontitis associated with a calcifying odontogenic cyst. International Endodontic Journal, 42, 539–545, 2009.Aim
To report a case of calcifying odontogenic cyst (COC) that was suggestive of apical periodontitis adjacent to the roots of the maxillary incisor teeth.Summary
Tooth 21 presented with clinical and radiographic signs of secondary infection, a post within the root canal and substantial internal tooth destruction; it was scheduled for endodontic surgery. Teeth 12 and 22 were root filled following the placement of a calcium hydroxide intracanal dressing for 21 days. Three attempts at root canal disinfection in tooth 11 were unsuccessful, and a persistent purulent drainage precluded completion of root canal treatment. Surgical enucleation of the periapical lesion was undertaken and the tissues submitted for histopathological examination. A diagnosis of COC was established based on the microscopic analysis. COC is an unusual benign lesion that represents 2% of all odontogenic lesions. Depending on the stage of development, it can mimic a large lesion associated with apical periodontitis and should therefore be considered in the differential diagnosis. In the case of COC, the definitive diagnosis can only be made with histopathological analysis.Key learning points
• Persistent apical periodontitis may be of nonendodontic origin.Key learning points
• Histological examination is essential to establish the cause of persistent apical periodontitis.Key learning points
• Calcifying odontogenic cyst can mimic apical periodontitis.