Pulpo-dentinal complex - segment of a tooth; human, adult

Stain: Hematoxylin and eosin. At the pulp-dentin border the peripheral pulp appears to be a specialized odontogenic region composed of odontoblasts, a cell-free zone and a cell-rich zone. From left to right: dentin (note striation due to dentinal tubules); (uncalcified) light stained predentin. At the transition to dentin mineralization starts as minute spherical aggregates of crystals (calcospherites) (irregular and darker stained structures). Odontoblasts (dark stained nuclei) with their cytoplasmic extensions (so-called odontoblastic processes or Tomes' fibers) running through the predentin. Light stained cell-free zone of Weil. Cell-rich zone (fibroblasts and collagen) of connective tissue in pulp chamber.