Hi, this has been on my mind for sometime now, and I wanted to ask you
all a few questions. I have read an article at Dental X-rays. I was
reading about it on medical health care info
http://www.medical-health-care-information.com/encyclopedia/D/Dental_X-rays.asp
which says  Dental X-rays are a type of picture of the teeth and
mouth. X-rays are a form of electromagnetic radiation, just like
visible light. They are of higher energy, however, and can penetrate
the body to form an image on film.
Structures that are dense (such as silver fillings or metal
restoration) will block most of the photons and will appear white on
developed film. Structures containing air will be black on film, and
teeth, tissue, and fluid will appear as shades of gray........
While it must be true, I wonder what you have to say about it. Do let
me know! Regards, Leena