“…Consequently, these primary cells must be replaced by a new generation of odontoblast-like cells. 27 Therefore, the formation of reparative dentin is a complex sequence of biological process, which is dependent on multiple factors, including the presence of responsive progenitor cells as well as the appropriate inductive molecular signals for induction of proliferation, migration, and differentiation of the new generation of odontoblast-like cells. The derivation of the progenitor cells for these odontoblast-like cells remains unclear although they may be variable.…”