Human canine milk tooth, coloured scanning electron micrograph (SEM). In humans, deciduous, also known as baby or milk, canine teeth are usually shed between 9 and 12 years where they are then replaced by permanent adult canine teeth. The canines help to rip and tear food making it easier to chew and eat. This tooth has been split in half to show the outermost enamel layer as well as the internal structures. Moving from the outside towards the middle are the outer enamel layer then the dentine layer followed by the pulp region which, if the tooth was in situ, would contain nerves and the blood vessels that feed the tooth and keep it healthy. Milk teeth may appear hollow when they fall out as the roots and internal contents slowly dissolve during the process. Magnification: x12 when printed at 10cm wide.