There are very few things that people do every single day. Into this small collection goes things like eating, sleeping and breathing. So it is amazing that, for nearly everyone in the U.S., tooth brushing falls into this category. Why, you might ask, has tooth brushing gained such tremendous importance - so much so that you have memories of tooth brushing from your earliest childhood? Because of the dreaded cavity - No one wants cavities when they visit the dentist!

To understand how a cavity works, we need to have a basic understanding of the anatomy of the tooth. A tooth is composed of several layers. The outermost layer (above the gum-line) is called the enamel. Enamel is the hardest and most mineralized substance in the body. Beneath the gum-line, a substance called cementum covers the tooth roots. Under the enamel and cementum is the dentin. The dentin is about as hard as bone, and, unlike the enamel, dentin contains nerve endings.

Beneath the dentin is the dental pulp. The pulp is a vascular tissue, composed of capillaries, larger blood vessels, connective tissue, nerve fibers, and cells including odontoblasts, fibroblasts, macrophages, and lymphocytes. The pulp is needed to nourish the tooth during its growth and development. After a tooth is fully mature, the only function of the pulp is to let us know if it is damaged or infected by transmitting pain.

In this article, Dr. Jerry Gordon explains how cavities form and how dentists create fillings to rebuild the tooth from the damage that they do and what can be done to prevent cavities in the first place. See the next page to get started.