Dental X-rays

[Ninni Jacob <njacob@gsosun1.gso.uri.edu>]

I would like to hear RADSAFERs' comments on having full mouth X-rays
taken. The following are the facts as I know it:

The American Dental Association recommends having full mouth X-rays taken
every 3 to 5 years.

Full mouth Xrays could range from 14 to 20 exposures (including four
bitewings).

The recommended cone-tip exposures (DENT RANGE) PER EXPOSURE  for good quality
films could range anywhere from 50mrem (100Kvp) to 320 mrem (50Kvp) for "E"
speed films and could range from 100 mrem to 575 mrem for "D' speed films.
depending on the Kvp.

When the patient asks the hygienist what kind of dose this entails she
says "It is equivalent to being outside for 30 days in a year" (meaning  30
days of background radiation). The dentist , on the other hand says: "It
is equivalent to being out in the sun for 30days". Apparently, thats what
their textbooks teach them.

The following are my questions:

1. Does anyone know what the actual dose to the face would be?
  Is the comparison that the hygienist made correct?
  Is there a scattered dose to the thyroid?

2. If there is a DIAGNOSTIC reason, there maybe no  question that this should
be done. But is is OK to be used as a SCREENING procedure? Is it ALARA?
Is there a benefit? Or is it just a money-making proposition for the dentist?

If you think it is of interest to the group, please post to RADSAFE. If
not please email me directly.

As always, thanks for your insight and input.


Ninni Jacob
Radiation Safety Officer
University of Rhode Island/
Rhode Island Nuclear Science Center
16 Reactor Road
Narragansett,RI 02882

Phone: (401) 789-9391
Fax:   (401) 782-4201
email: njacob@gsosun1.gso.uri.edu