Re: Risk from dental x ray

["Gibbs, S Julian" <s.julian.gibbs@vanderbilt.edu>]

All comments on this issue are appropriate.  Over the past 
20 years or so I have devoted most of my time to study of 
patient exposure from diagnostic x ray, especially dental.  
We have developed a Monte Carlo radiation transport code 
that provides specific organ doses to the entire body.  The 
results as effective doses in microsievert:
Procedure		Typical technique State of the art
Full mouth intraoral, 21 film	350		45
Bitewing, 4 film		70		8
Panoramic, 1 film				20
(Gibbs et al, Dentomaxillofacial Radiology 17:15, 1988)

I too have used time of environmental exposure that gives 
the same effective dose as the diagnostic exposure.
However, the more compelling issue is simply: Is the 
exposure justified on clinical grounds?  Dentists have been 
trained to perform repeat radiography on asymptomatic 
patients at regular intervals.  In many offices this is 
done by the dental hygienist before the dentist sees the 
patient.  Now there are high-yield criteria for deciding on 
the diagnostic need for radiographs, based on history and 
physical exam. I would therefore advise the patient to ask 
the dentist to justify the exposure on clinical grounds.  
Clinically indicated and justified radiographs should be 
obtained on grounds that the expected health benefit should 
outweigh any radiation risk.  On the other hand, exposure 
that is not justified is by definition wasted.
Hope this helps.
***********************************************************
S. Julian Gibbs, DDS, PhD               Voice: 615-322-3190
Professor of Radiology                    FAX: 615-322-3764 
Dept. of Radiology & Radiological Sciences
Vanderbilt University Medical Center
Nashville TN 37232-2670 Email:s.julian.gibbs@vanderbilt.edu
***********************************************************
"Where there's a will there's a family!"  -Anonymous

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