The term 'Tooth Stuff' can be broken down into two crossword solutions, 'PULP' and '4 letters'. PULP is a soft, moist, and fibrous material that is found in the center of teeth. It is made up of living cells, connective tissue, and dentin, which is a hard, calcified tissue. The PULP is responsible for providing nutrients to the tooth and helping it to grow. It also helps to protect the tooth from bacteria and other harmful substances.