Molecular determinants of cranial neural crest-derived odontogenic ectomesenchyme during dentinogenesis

Positional information on tooth morphogenesis is investigated by the identification of when and where phenotypic markers are expressed during odontogenesis. This temporal and positional information is correlated with the instructive and permissive signaling required for both dentinogenesis and amelogenesis. Of particular interest is the establishment of a map for the cranial neural crest-derived dental papilla ectomesenchyme and the odontoblast cell lineages. The expression of ectomesenchyme-derived cytotactin, dentin phosphoprotein, and epithelial-derived enamel proteins was studied in mice using embryonic, fetal, and postnatal mandibular first molar tooth organ development. This review summarizes the observations in the context of instructive epithelial-mesenchymal interactions and suggests that amelogenesis imperfecta and dentinogenesis imperfecta may in part be explained by alterations in these differentiation markers. Recombinant DNA methods should facilitate future investigations of these inherited dental disorders.