Age-related changes in the immunoreactivity of the monocyte/macrophage system in rat molar pulp after cavity preparation

Objective. Our objective was to compare the response of the monocyte/macrophage system of dental pulp to cavity preparation in aged rats (12 and 18 months old) with that seen in young adult rats (3 and 6 months old). Study Design. Cavities were prepared on the upper first molars, and the lower first molars served as intact controls. Specimens were collected at 1 day after cavity preparation, and cryostat sections were made. Results. Accumulation of OX6+ antigen-presenting cells along the pulp-dentin border and a marked increase in cell size ED2+ resident macrophages were noted in both young adult and aged rats after cavity preparation. In both cases, the number of ED1+ cells increased significantly after cavity preparation because of infiltrating monocytes. Conclusion. These findings suggest that the pulpal defense reaction of the monocyte/macrophage system to cavity preparation in aged rats does not differ markedly from that in young adult rats. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;94:103-10)