How Often Should my Dentist take X-Rays?
By Mina Levi, DDS, 06/11/2015

Many of our patients at the dental office of San Francisco Dentist Mina Levi, DDS are concerned and have questions about the dental digital x-rays we take for them periodically. Some questions include: ‘how much radiation will the x-rays emit?’, ‘how often should dental x-rays be taken?’ and ‘why do we need to take x-rays?’ In this week’s article, Dentist San Francisco Mina Levi, DDS discusses why we need to take digital x-rays and how often they should be taken.

Digital Dental X-rays

What are digital dental x-rays?
Dental x-rays are images of the internal structure of the teeth using electromagnetic radiation. With digital x-rays, traditional photographic film is not needed and the dentist can see the images immediately without having to develop film. Another advantage to digital x-rays is that there is less radiation emitted than traditional x-rays.

How much radiation is emitted by digital x-rays?
An estimated 1% of cancer cases may be associated with medical/dental radiation. Medical radiation is about 8 times more than dental. One-time dose in uSv can cause:
· 100,000 - Thyroid Cancer
· 250,000 - Skin Cancer
3D dental x-ray doses are about 0.002% of this amount. The following table describes radiation sources and the effective dose exposure:

Radiation Source
Effective Dose Exposure (uSv, ICRP 2007)
Average Daily Background Exposure (US)
Dental Bitewing X-Ray, Digital/F-film
Average Daily Total Exposure (US)
Dental Bitewing X-Ray, D-Speed Film
One Hour of High-Altitude Air Flight
X-Ray - Chest
X-Ray - Skull
Dental FMX (18), Digital X-Ray
Promax CBCT, Focus Area
Promax CBCT, Lower Skull
Promax CBCT, Full Skull
Dental FMX, D-Speed Film
X-Ray - Mammogram
X-Ray - Hip
CT - Head
X-Ray - Lumbar Spine
X-Ray - Abdomen
CT - Chest
CT - Abdomen
CT- Cardiac

Why do we need to take digital x-rays?
Digital x-rays are taken because they show the dentist the condition of your teeth and roots beyond what the naked eye can see. These images can help the dentist determine the degree of periodontal (gum) disease, can show abscesses or abnormal growths, can show the beginning of or position of dental decay or cavities and much more. If the cavity, infection or other issue is not visible in the mouth, it is almost impossible for the dentist to make a diagnosis without x-rays.

How often should my dentist take digital x-rays?
The frequency at which your San Francisco dentist takes digital x-rays depends on your health history and dental health needs. Usually, a small set of about six x-rays (4 BW, 2PAs) is taken once per year with your routine exam to monitor growth or lack of growth of dental decay and make sure that no new areas of decay have emerged. A full set of about eighteen x-rays (FMX) is taken once every three to five years for a more thorough picture of the teeth and jaw.

If you have questions regarding digital dental x-rays or when you should be getting them taken, visit Dentist San Francisco Mina Levi, DDS on the web at or give us a call at (415) 513-5066.