Acute Apical Periodontitis : Histology
A. The apical region of the root canal pulp is infiltrated by inflammatory cells; the toxins that are released during the inflammatory process elicit the periapical inflammatory reaction.
B. Coronally one observes necrotic tissue, but further apically the tissue contains only individual inflammatory cells. The cavitation and apparent dissolution of the pulpal tissues from the canal wall are artifacts.
C. Enlarged section from the coronal zone of necrosis exhibiting a wall of neutrophilic granulocytes.
D. Periapical accumulation of inflammatory cells; also the simultaneous appearance of
resorption lacunae indicate dentinoclastic and osteoclastic activity.
E. The enlarged section from the periapical region exhibits a massive accumulation of acute polymorphonuclear granulocytes.