Cavities Between Teeth

What Cause Cavities Between Teeth (Interproximal Cavities)?

Cavities in between teeth are commonly referred to as interproximal cavities or decay by your general dentist. Cavities form when there is breakdown of the outer, calcified enamel of the tooth by bacteria commonly found in the human mouth. The bacteria stick to the teeth, embedded in a hard substance called dental plaque or calculus, which deposits on your teeth. Plaque often forms in between the teeth due to the inability of toothbrushes to properly clean these tough-to-reach areas of the mouth. These bacteria break down sugars and carbohydrates, resulting in an acid attack that breaks down the enamel of the tooth and causes the cavities.

Interproximal Cavities Diagnosis

The diagnosis of interproximal cavities is usually made by an X-ray called a bite wing. This type of X-ray allows the dentist to accurately assess the extent of the dental cavity. The depth of the cavity is usually deeper than it appears on the radiograph. Although a clinical assessment by visual inspection can be made by your dentist, bite wings are a crucial tool for early detection. A dental solution that visualizes the cavities can also be used in children instead of X-rays.

If the decay has only extended half way into the enamel of the tooth, these “incipient” cavities often can be recalcified with a fluoride gel. Once the cavity penetrates deeper into the enamel of the tooth, a filling is usually the appropriate treatment. The material of choice for dental fillings is either a white colored composite (synthetic material) or an amalgam containing silver. If these cavities go untreated, more extensive dentistry could be necessary such as a crown or root canal.

Symptoms of Interproximal Cavities

Most symptoms occur when the cavity has penetrated into the dentin, the second hard layer of tissue beneath the enamel. Symptoms of these cavities include

  • sensitivity to cold or
  • sweets or
  • even trouble chewing on the tooth with the cavity.

The best way to prevent interproximal decay is to floss the teeth in conjunction with daily brushing. The floss helps break up the plaque that has an affinity for the interproximal area. Fluoride rinses also are useful in toddlers and younger patients.


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Medically reviewed by Kenneth Rotskoff, MD, DDS; Board Certified Dentistry, Oral/Maxillofacial Surgery


Chow, Anthony W, MD, FRCPC, FACP. "Complications, diagnosis, and treatment of odontogenic infections." UptoDate. Oct 6, 2016.