Regarding X-Ray Radiation

Regarding x-rays: The body can tolerate small doses of radiation to limited areas of the body much better than whole body radiation. The xray tube head absorbs most of the scatter radiation from going elsewhere than your mouth where the film is being targeted. Small doses of radiation (like that experienced by xrays at a dental office) is undetectable in cells because it's equivalent to the natural cellular damage due to aging. To give you some values with how much radiation you get from dental xrays, they account for 0.01 mSieverts per year in a localized area, meanwhile you are exposed to 3.0 mSieverts whole body radiation due to natural sources (1.2 mSv just from radon in the soil!). So, you get 300 times that amount of radiation on a yearly basis just from the soil! Even external (0.5 mSv) and Cosmic (0.4 mSv) radiation account for 10 times more radiation than you get from dental xrays.

To put it in terms of Grays (a unit of energy absorbed per unit tissue), 18 (separate) dental films would amount to a total of 0.23 mGrays of exposure to your thyroid gland whereas the amount of Grays that is needed to put your thyroid tissue at an increased risk for tissue damage is 60 mGrays... So a dentist would have to take 260 sets of 18 separate films to put you at an increased risk for tissue damage to your thyroid. Or in terms of single films (since most dentists don't do full-mouth survey sets of films anymore and only usually do 4-6 films each year per patient), they would have to take 4695 films to put you at risk for tissue damage. Risk means there's just a chance....

We do our best to keep our xrays limited in the dental office given the possibility that each patient might undergo much more intensive xrays at medical offices if they have other medical conditions that they undergo xrays for on a routine basis. We will use the thyroid collar (which is separate usually) with apron as an additional protector, but as you can see, the doses are SO low that it isn't really necessary.