Cap Stage
During this stage, cells begin to shape the outside layer of the tooth, forming a cap that sits on the rest of the tooth bud. This cap is called the enamel organ because it will later form the cells that produce enamel. The rest of the tooth bud, known as the dental papilla, will make the two interior layers of the tooth: the dentin and the pulp.
Another sac of cells, called the dental follicle, surrounds both the enamel organ and the dental papilla. This sac contains blood vessels and nerves. By the cap stage, three different structures make up the tooth germ: the enamel organ, the dental papilla and the dental follicle.