Dentin

Dentin is a hard, yellowish- to a light-brown substance that makes up the bulk of a tooth. It acts as dentine and an organic component. The dentinal fluid is located within dentin tubules and surrounds odontoblasts by means of a long channel called a dentinal channel. Dentin comprises 70% in weight in the crown area, but it collapses towards the root area where its density can account for 40%.