What Are Teeth Made Of?

Your teeth are an amazing structure of interrelated layers. I'll discuss them below from the outside-in.

Enamel

The outside layer of the tooth you can see is called enamel. Enamel is a crystal matrix of Calcium, Phosphate and Hydroxide ions. Because enamel is mostly mineral, it is the hardest layer of the tooth. Standing alone, enamel is actually translucent.

Cementum

Cementum coats the roots of your teeth, and is hidden underneath the gums. Unlike enamel, cementum is a softer outer coating that allows your gums to hold tight to the tooth root. Cementum is made of half mineral and half protein material and water. 

Dentin

Dentin lies underneath enamel and cementum. It consists of tightly packed tubes surrounded by mineral crystals, protein and some water. Although dentin still contains mostly mineral crystals, it is much softer than enamel and can be penetrated more easily during the cavity process. Fluid movement in dentin tubes causes tooth sensitivity. Dentin also gives a tooth its unique color.

Pulp

The pulp is the only part of the tooth that contains blood vessels and nerve fibers. This innermost layer keeps the tooth alive, registering both pain and sensitivity messages to your brain. Invasion (cavity) or exposure (broken tooth) of a living pulp typically registers as intense pain, due to the sensitive nerve fibers that live there. Protect the pulp! A dead pulp means a dead tooth.