Pulp Extracellular Matrix
Collagen fibrils and non-collagenous extracellular matrix components may be extracted from the dental pulp. Differences appear between the coronal and radicular pulp after mechanical preparation. Type I, III, V, and IV collagens have been identified. Othe
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Pulp Extracellular Matrix Arthur Veis and Michel Goldberg
3.1
Introduction
Many features of the pulp anatomy and pulp cells have already been described in Chaps. 1 and 2 but a few general remarks are in order here to clearly define the scope of this discussion of the pulp extracellular matrix. At the earliest stage of each tooth’s development, the epithelial neural crest derived cells at each tooth-defined position along the dental lamina fold forming a complex three-dimensional bud which invaginates into the underlying mesenchyme. The epithelial dental lamina remains as a continuous layer, with an intact basement membrane but, for each tooth the lamina bud grows into a different and particular cap-like shape. Cells in the interior of the folded bud become the enamel organ, The epithelial cells lining the concave part of the interface with the opposing mesenchymal cells divide and spread forming a layer of “inner enamel epithelium (IEE)” cells. This layer expands to surround and enclose the mesenchyA. Veis, PhD Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA e-mail: [email protected] M. Goldberg, DDS, PhD (*) Department of Oral Biology, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, 45 Rue des Saints Pères, Paris 75006, France e-mail: [email protected], [email protected]
mal cells destined to become the dental papilla and defines the three dimensional shape of the tooth crown. The cells of the IEE ultimately become preameloblasts, which upon maturation, become secretory ameloblasts and form the tooth enamel, which mineralizes. The “trapped” mesenchyme is destined to become the “dental papilla” and in the fully formed tooth, the “dental pulp.” The cuboidal ectomesenchymal neural crest cells opposing the basement membrane at the IEE interface form a layer and develop into pre-odontoblasts which mature into secretory odontoblasts (OD) and ultimately form the mineralized dentin. The extension of the IEE into the mesenchymal tissue ceases upon reaching the position of the tooth cervix, at which the cervical loop forms and merges on the outer aspect of the enamel organ and the layer of epithelial cells is now called the outer enamel epithelium (the OEE). In three dimensions the formation of the cervical line marks the limit of the tooth crown. However, tooth growth does not stop. The layer of ectomesenchymal neural-crest derived odontoblastic cells continues to divide and extend to form the root dentin. The OD comes to face the mesodermal-derived mesenchyme containing a variety of cells of different character, but including bone-like cementoblasts. These cementoblasts produce mineralized cementum in opposition to the mineralized radicular dentin. Tooth growth ceases when the root apex is reached. Why begin a discussion of the tooth pulp with a description of overall tooth development?
M. Goldberg (ed.), The Dental Pulp, DOI 10.1007/978-3-642-55160-4_3, © Springe
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