for patients
Should I be worried about dental x-rays?
"Graphic Science: Exposed" from Scientific American May 2011 issue
As you can see in this diagram that I have included from Scientific American, the amount of radiation dose from a single dental bitewing x-ray, 0.005 millisieverts (mSv), is very small, especially when compared to imaging technology used in other fields of medicine. To put this value into perspective, in 1 year we are exposed to around 3.1 mSv of naturally occurring radiation from our environment. This would be the equivalent of taking 620 dental bitewing x-rays!
Despite the minimal amounts of radiation, as dentists, we always weigh the potential risk of dental x-rays with the benefits. In fact, there can be enormous benefits:
DIAGNOSE CONDITIONS that cannot be seen by looking in the mouth:
- Caries hidden in between teeth or underneath old fillings and crowns
- Bone loss that accompanies gum disease or peri-implant disease
We take them during treatment to PERFORM TREATMENT accurately:
- Root canal treatments
- Dental implants
We take them before treatment to PLAN TREATMENT:
- Surgical approach for extractions and to assess anatomical structures (i.e. nerves, sinus)
- For fillings to assess proximity of deep decay to the nerve of the tooth
There is a principle in radiation safety called ALARA or As Low As Reasonably Achievable. We use this when prescribing dental x-rays to make sure that we expose to the patient to as little radiation as is needed.
For your reference, here are the different types of x-rays we use in dentistry and their respective effective doses to the body:
| X-Ray Type | Effective Dose (mSv) |
|---|---|
| Bitewing, periapical | 0.005 |
| Panoramic | 0.014 - 0.024 |
| Cone Beam CT | 0.034 - 0.089 |
1. Ionizing radiation exposure of the population of the United States, Bethesda, Mtd.: National Council on Radiation Protection and Measurements. 2009. ISBN 978-0-929600-98-7. NCRP No. 160.
2. Roberts JA, Drage NA, Davies J, Thomas DW. Effective dose from cone beam CT examinations in dentistry. Br J Radiol. 2009 Jan;82(973):35-40. doi: 10.1259/bjr/31419627. Epub 2008 Oct 13. PubMed PMID: 18852212.
3. Ludlow JB, Davies-Ludlow LE, White SC. Patient risk related to common dental radiographic examinations: The impact of 2007 International Commission on Radiological Protection recommendations regarding dose calculation. Journal of the American Dental Assoc 139:1243; 2008.