Dental Cavities

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What are cavities?

Dental cavities are holes in teeth caused by tooth decay. Cavities are also referred to as caries.

How does a cavity form?

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Two main factors contribute to tooth decay -- bacteria and a diet high in sugar and starch. There are over 500 different types of bacteria that are normally present in the mouth. These bacteria combine with food and saliva to form a sticky substance called plaque that attaches to teeth. Foods rich in starches add to the stickiness of the plaque, which begins to get hard if it remains on the teeth after a couple of days and turns into tartar or calculus. Bacteria in the plaque convert sugar into acid that dissolves the tooth structure causing holes, or cavities. Because of these two contributing factors, dental caries have been described as a “dietobacterial” disease.

The parts of teeth that are most vulnerable to tooth decay are areas where plaque can accumulate most easily. Plaque tends to settle into the pits and fissures in the tops of teeth, into the areas in between the teeth, and next to the gum line. Where there is plaque, there are bacteria and acid, and eventually destruction of the tooth surface. The cavity starts in the outer layer of the tooth (enamel) and as it gets deeper, penetrates into the softer inner layer of the tooth (dentin.) Typically, it isn't until the decay reaches the dentin that a person will start to notice signs and symptoms of the cavity.

What risk factors contribute to tooth decay?

Saliva helps prevent plaque from attaching to teeth and helps wash away and digest food particles. A low salivary flow or dry mouth leaves the teeth more vulnerable to tooth decay. Genetic factors that affect tooth decay are tooth size and shape, thickness of enamel, tooth position, tooth eruption time and sequence, and the bite.

Medically Reviewed by a Doctor on 6/29/2012

Patient Comments

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Dental Cavities - Treatment Question: Are you afraid to undergo treatment for cavities?
Cavities - Treatment Question: Do you or your child get lots of cavities or have several fillings? Please discuss treatment, including sealants.
Cavities - Oral Hygiene Question: Please share tips for preventing cavities from forming. Do you or your kids chew xylitol gum?

Cavities Between Teeth

Cavities in between teeth are commonly referred to as interproximal cavities or decay by your general dentist.


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