Human teeth are often mistaken for ivory due to their similar appearance. Despite this superficial resemblance, teeth and ivory have distinct biological structures and compositions. While both are calcified tissues, they serve different functions and originate from different biological contexts.
What is Ivory
Ivory is a hard, white material primarily composed of dentin, a calcified tissue found in the teeth and tusks of various mammals. While elephants are the most well-known source, other animals like walruses, hippopotamuses, narwhals, and some wild boars also produce ivory. Its chemical structure consists mainly of collagen fibers mineralized with hydroxyapatite, a form of calcium phosphate. This composition gives ivory its characteristic density, making it historically valuable for carving.
The Structure and Makeup of Human Teeth
Human teeth are complex biological structures designed for chewing food. They consist of four main components: enamel, dentin, pulp, and cementum. Enamel forms the outermost layer of the tooth crown, serving as the hardest substance in the human body. It is highly mineralized, primarily with hydroxyapatite crystals.
Beneath the enamel lies dentin, which constitutes the bulk of the tooth structure. Dentin is less mineralized than enamel, composed of inorganic minerals, organic material (primarily collagen), and water. It is softer than enamel but harder than bone, providing support and flexibility to the brittle enamel layer. The innermost part of the tooth is the pulp, a soft tissue containing nerves, blood vessels, and connective tissue, which supplies nutrients and sensation to the tooth. Covering the root of the tooth is cementum, a bone-like tissue that helps anchor the tooth within the jawbone.
Distinguishing Teeth from Ivory
The main distinction between human teeth and ivory lies in their overall structure and composition. Human teeth possess an outer layer of enamel, the hardest biological substance, which is largely absent in most forms of ivory. While both contain dentin, its proportion and arrangement differ significantly. Ivory, especially from elephants, is almost entirely dentin and lacks the protective enamel layer found on human tooth crowns.
Biological function and origin species are also differentiators. Human teeth are adapted for chewing and are part of the digestive system. Ivory, conversely, originates from the tusks or specialized teeth of certain large mammals, serving purposes like foraging, defense, or display. The dentin in elephant ivory also exhibits a unique cross-hatched pattern known as Schreger lines, which is not present in human teeth. These differences highlight why human teeth are not considered ivory, despite some shared basic components.