Dentine
Dentine is a calcified tissue that constitutes the bulk of tooth structure in vertebrates. It is situated between the outer enamel layer and the inner pulp chamber, serving to provide structural support and protection to the tooth. The tissue is composed primarily of mineral crystals embedded within an organic matrix of collagen and other proteins.
In terms of physical properties, dentine occupies an intermediate position regarding hardness and mineralization. It is less mineralized than enamel but significantly more mineralized than bone, providing a balance of rigidity and resilience. This composition allows it to withstand the mechanical stresses of mastication while remaining slightly flexible enough to prevent catastrophic fracture.
The evolution of dentine played a critical role in the success of early vertebrates, particularly during the Paleozoic era. In sharks, which dominated the “Golden Age of Sharks,” dentine formed the core of numerous teeth that were continuously replaced throughout their lifetimes. This adaptation allowed for sustained predatory efficiency in diverse marine environments, contributing to the group’s long-term evolutionary survival.