The dentin–pulp border is a dynamic interface where odontoblasts form the organic matrix and mineralize it to form dentin. Even though dentin and odontoblasts are often compared to other mineralized tissues (bone and osteoblasts), dentin is in many ways a unique tissue, and odontoblasts are unique cells with distinct morphological and functional differences from osteoblasts. Unlike osteoblasts, odontoblasts may remain vital for the person's lifetime. Dentin formation and mineralization is also in some ways different from the bone formation. Dentin contains dentinal tubules that may be patent all the way from the dentin–enamel junction to the dentin–pulp border, making dentin (and pulp tissue) theoretically accessible to oral microbes and other noxious stimuli during or immediately after the destruction of enamel or cementum covering dentin. Odontoblasts are the first cells facing the external milieu (oral cavity), and together with the pulp tissue they must be able and ready to react to external microbial or other irritations. Recent discoveries actually indicate that odontoblasts are better equipped to respond to external stimuli than previously believed. In addition to forming dentin, odontoblasts may have sensory functions, and they may also sense and respond to microbial antigens in much the same manner as immunological cells. Both of these functions indicate that odontoblasts are more active in the regulation of the defensive reactions of the dentin–pulp complex, including fine‐tuning pulp inflammatory reactions. The aim of this review is to provide an update on the current knowledge of the different aspects of dentinogenesis, as well as the potential roles of odontoblasts on other functions in the dentin–pulp complex.