The hardest substance in the human body is found in the mouth. It is enamel, which is found on the surface of teeth. However, enamel can also be damaged: especially flavored waters and carbonated drinks can cause enamel erosion. Dentine is found under the enamel. The inside of the tooth contains cementum and pulp. Pulp is made up of connective tissue, blood vessels and nerve fibres. Its function is to supply nutrients to your teeth. The pulp cavity extends into the root of your teeth, forming the root canal.