ABSTRACT
PROBLEM: The role of bacteria has been well established in pulpal and periapical diseases, but the contribution of the host defenses is less clear. OBJECTIVES: The purpose of this study was to compare periradicular lesion development in immunosuppressed rats with that in normal rats. STUDY DESIGN: Fifteen rats were given weekly injections of Cytoxan (Bristol Laboratories) to suppress their immune systems. The pulps of mandibular first molars of these animals and another 15 rats that had received no medications were exposed and left open to their oral flora. The rats were killed at 2, 4, and 6 weeks. Radiographic analysis was performed by means of a computer linked to a digitizing board and stylus. In addition, specimens were decalcified, sectioned, stained, and examined under a microscope with a grid to quantify relative percentages of surface areas of bone, root, periodontal ligament, marrow spaces, soft tissue, and inflammatory infiltrate. RESULTS: Statistical analysis showed a significantly greater radiographic bone loss in the immunosuppressed group only at 4 weeks. No significant histologic differences were found between the two groups. CONCLUSION: Our results suggest that reduction of circulating leukocytes may not significantly affect the development of periradicular pathosis in rats.
