Irreversible Pulpitis : Histology
- The advanced dentin caries beneath the fissure has reached the pulpal tissues; note the accumulation of inflammatory cells. The root canal pulp exhibits several diffuse calcifications, but is inflammation-free.
- Within the coronal pulp, one notes a massive inflammatory cell infiltration with small areas of tissue disintegration.
- The bacteria within the dentinal tubules attract neutrophilic granulocytes. “Empty spaces” in the subodontoblastic layer represent micronecrosis, with pus accumulation and polymorphonuclear granulocytes.
- Granulocytes dominate both perivascularly as well as intravascularly; this is the picture of persisting chemotactic irritation. Larger “empty spaces” represent initial tissue necrosis. One also notes plasma cells and macrophages, which produce cytokines and chemokines, leading to chemoattraction of leukocytes. These mobilize monocytes, neutrophilic granulocytes, and other effector cells, attracting them to the focus of infection.