Induced periapical lesions in ferret canines: histologic and radiographic evaluation.

Ferrets have been utilized in endodontic research to study periapical responses. However, various aspects of induction and healing of periapical pathosis in ferrets are unclear. This study evaluated the radiographic and histopathologic features of induced periapical lesions. Periapical pathosis was consistently produced in 8 canines of 2 ferrets by extirpating the pulp, leaving the cavities open for a week, then sealing for 12 weeks. The resulting lesions were evaluated radiographically every two weeks. The animals were then killed and the induced lesions evaluated histologically and histobacteriologically. Four untreated canines from 2 other ferrets were used as controls. Results showed that periapical rarefactions were visible in all teeth in the experimental group within 4 weeks. Histologically, the induced lesions consisted principally of a mononuclear inflammatory infiltrate, dominated by macrophages but with numerous lymphocytes. With Brown & Brenn staining, bacteria were demonstrated in the pulp space of teeth in which the lesions were induced and in the apical arborization of the canal system. Only one specimen had bacteria within the periapical lesion.