How can a dental x-ray diagnose a cavity?

Dental X-rays are a useful diagnostic tool when helping your dentist detect damage and disease not visible during a regular dental exam. X-rays show the areas under the gum, such as roots of teeth that cannot be seen otherwise. It is in these areas where tooth root decay can form and lead to cavities. 

A dental x-ray can show areas of potential tooth decay because those areas look darker (less opaque) on the x-ray than a healthy tooth. Training and experience allow the dentist to interpret the x-ray and determine the appropriate course of treatment.
Dental x-rays take pictures of the mouth and teeth which show the densities of the different tissues. Dental cavities can show up in these pictures before the cavities are seen in a visual exam. Dentists take x-rays periodically to keep track of changes in the teeth, usually every one to three years.

Continue Learning about Cavities


Cavities are tiny holes in your teeth that have developed from decay. Left untreated, cavities will get larger, and can cause toothache and possible loss of teeth. Anybody can get a cavity, but you put yourself at greater risk if ...

you don't brush regularly, or frequently consume sweets or sugary drinks. Your dentist can help prevent cavities with fluoride treatments, and can find them by taking pictures (X-rays) of the teeth. Once found, the dentist may treat your cavity with a filling or if extensive, with a crown. If there has been an extensive infection, other treatments, including antibiotics or a root canal surgery may be indicated.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.