At Smiles by Design, we have heard, “But I brush my teeth!” when we inform a patient that they have a cavity many times. We understand that the word cavity is a cause for concern to many, and even frightening to some, but cavities can and still do occur. Some people are more prone to cavities than others, but every cavity is caused by the normal activities of the mouth. Carbohydrates in food are broken down by bacteria that release acids.