Answer to Question #3725 Submitted to "Ask the Experts"

My wife was a dental hygienist for 30 years. She developed breast cancer six years ago. She recently passed away. I have always worried about her exposure to radiation as a result of performing several x rays each day. I am looking for information on any studies which have been conducted on this sort of repeated exposure. I would appreciate any leads you might be able to provide.

Please accept our sympathy on the recent illness and death of your wife. It is extremely unlikely that her disease was in any way related to occupational exposure to radiation. A number of studies have been published of radiologic technologists and others exposed to occupational doses much greater than your wife received as a dental hygienist. Two of special interest are:

1. Mohan AK, Hauptmann M, Linet MS, Ron E, Lubin JH, Freedman DM, Alexander BH, Boice JD Jr, Doody MM, Matanoski GM. Breast cancer mortality among female radiologic technologists in the United States. J Natl Cancer Inst. 2002 Jun 19;94(12):943-8.
   
   The authors reported a statistically significant association between occupational radiation exposure and breast cancer during the early years of radiology, when equipment was cruder and there were no limits to occupational dose. However, in those working since about 1950 the association essentially disappeared.
    
2. Boice JD Jr, Mandel JS, Doody MM. Breast cancer among radiologic technologists. JAMA. 1995 Aug 2;274(5):394-401.
   
   This paper reported studies in which known cofactors for breast cancer were analyzed. No association with radiation was found.

Many other studies can be found in the references given in these papers or from the National Library of Medicine.

Conclusion: There should be no concern regarding breast cancer in a dental hygienist being related to occupational exposure to radiation. Occupational doses reported for dental personnel are little more than natural background doses for typical Americans.

S. Julian Gibbs, PhD, DDS