Tooth Decay

What is tooth decay?

In short, tooth decay is a location on a tooth where so much of the tooth's mineral content as been dissolved away that a defect (a hole or a "cavity") has formed.

Now, let's back up a few steps and start a discussion about tooth decay so this blurb of a description makes more sense.

Tooth anatomy as it relates to tooth decay.

First off, you need to think in terms of a tooth being a hard calcified object. Yes, teeth do have nerves in their centers and this tissue is soft, but the surface of a tooth (where tooth decay begins) is formed from types of tissues that are very high in mineral content. These tissues are called enamel and dentin. Our mock up of a dental x-ray shown to the right illustrates where the dentin and enamel portions of a tooth are located.

Enamel

The vast majority of the surface portion of a tooth that is visible is covered by enamel. You've probably heard that tooth enamel is the hardest tissue found in the human body. This is true. Enamel is more than 95% mineral in composition. Most of this mineral content is a compound called hydroxyapatite which, as you probably already know, is rich in calcium.

Dentin

You may be surprised to learn that teeth are not solid enamel. Only the portion of a tooth that nature intended to lie at and above the gum line is covered by enamel. The bulk of a tooth, both its root and inner aspects, is composed of another calcified tissue called dentin. Dentin also contains the mineral hydroxyapatite, but to a lesser degree than enamel. Only about two thirds of the content of dentin is mineral so, relatively speaking, dentin is "softer" than enamel.