Critical Reviews in Oral Biology & Medicine, Vol 12, 425-437, Copyright © 2001 by International & American Associations for Dental Research
Induction and regulation of crown dentinogenesis: embryonic events as a template for dental tissue repair?
A. J. Smith and H. Lesot
Oral Biology, School of Dentistry, University of Birmingham, UK. a.j.smith.den@bham.ac.uk
Close regulation of odontoblast differentiation and subsequent secretory
activity is critical for dentinogenesis during both embryogenesis and
tissue repair. Some dental papilla cells achieve commitment and specific
competence, allowing them to respond to epithelially derived inductive
signals during the process of odontoblast differentiation. Temporo-spatial
regulation of odontoblast differentiation is dependent on matrix-mediated
interactions involving the basement membrane (BM). Experimental studies
have highlighted the possible roles of growth factors in these processes.
Regulation of functional activity of odontoblasts allows for both ordered
secretion of the primary dentin matrix and maintenance of vitality and
down-regulation of secretory activity throughout secondary dentinogenesis.
After injury to the mature tooth, the fate of the odontoblast can vary
according to the intensity of the injury. Milder injury can result in
up-regulation of functional activity leading to focal secretion of a
reactionary dentin matrix, while greater injury can lead to odontoblast
cell death. Induction of differentiation of a new generation of
odontoblast-like cells can then lead to reparative dentinogenesis. Many
similarities exist between development and repair, including
matrix-mediation of the cellular processes and the apparent involvement of
growth factors as signaling molecules despite the absence of epithelium
during repair. While some of the molecular mediators appear to be common to
these processes, the close regulation of primary dentinogenesis may be less
ordered during tertiary dentinogenic responses.
