The part in the center of a tooth made up of living soft tissue and cells called odontoblasts[WP].
Comment:
[homology-note] "The oral cavity of vertebrates is generally thought to arise as an ectodermal invagination. Consistent with this, oral teeth are proposed to arise exclusively from ectoderm, contributing to tooth enamel epithelium, and from neural crest derived mesenchyme, contributing to dentin and pulp (reference 1); Teeth and tooth-like structures, together named odontodes, are repeated organs thought to share a common evolutionary origin. These structures can be found in gnathostomes at different locations along the body: oral teeth in the jaws, teeth and denticles in the oral-pharyngeal cavity, and dermal denticles on elasmobranch skin (reference 2).[uncertain][VHOG]" xsd:string {date_retrieved="2012-09-17", external_class="VHOG:0001469", ontology="VHOG", source="DOI:10.1038/nature07304 Soukup V, Epperlein HH, Horacek I, Cerny R, Dual epithelial origin of vertebrate oral teeth. Nature (2008), DOI:10.1186/1471-2148-11-307 The homology of odontodes in gnathostomes: insights from Dlx gene expression in the dogfish, Scyliorhinus canicula. BMC Evolutionary Biology (2011)", source="http://bgee.unil.ch/"}