The outside of the tooth is made up of white enamel and a hard layer called the dentin. Inside the tooth is the pulp, or soft tissue, which contains blood vessels, nerves and connective tissue. The pulp extends from the crown of the tooth to the tip of the root where it connects to the mouth tissue surrounding the root.
An important factor in dental development, the pulp creates the surrounding hard tissues as the tooth grows. Once a tooth is fully mature, however, it can survive without the pulp because the tissue surrounding the tooth continues to nourish it.