A very few people other than dentist know that our teeth consist of three layers. First is the hard outer layer known as enamel. Second being dentin the tissue which is below enamel. Pupil is the center that contains the nerves and blood supply. There are two types of stains on teeth: extrinsic stains on the enamel and intrinsic stains in the dentin, which show through the enamel. Read the rest of this entry »