Tooth. Polarised light micrograph of a section through a molar tooth in the lower jaw. Molar teeth are used for grinding up and chewing food. The crown of this tooth has a cap of enamel (grey band, top centre). This is the hardest substance in the body, and prevents wearing of the tooth. The tooth is anchored in the gum by its roots (green/blue, running to lower left and right here). The pulp cavity (black, upper centre) contains nerves and blood vessels. The pulp is surrounded by dentine (many colours) which forms the bulk of the tooth. This is a tissue similar to bone but harder.