This document discusses dentinogenesis, the formation of dentin by odontoblasts. It describes the different types of dentin formed at various stages - mantle dentin, primary dentin, secondary dentin, and tertiary dentin. It also discusses the regional distribution and structure of different zones of dentin, including mantle dentin, circumpulpal dentin, secondary dentin, tertiary dentin, predentin, interglobular dentin, and the granular layer of Tomes. Additionally, it compares intratubular and intertubular dentin, and provides notes on sclerotic dentin, dead tracts, incremental lines of Von Ebner and Andersen, lines of primary