dental caries

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The formation of cavities in the teeth by the action of bacteria; tooth decay.
• noun Cavities in the teeth formed by such action.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun tooth decay; a disease of the teeth resulting in damage to tooth structure.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun soft decayed area in a tooth; progressive decay can lead to the death of a tooth