Answer to Question #11372 Submitted to "Ask the Experts"
The following question was answered by an expert in the appropriate field:
Dental crowns are increasingly made with zirconia (zirconium dioxide). How radioactive is zirconia and is it safe in one's mouth? Is porcelain less radioactive? Regarding radioactivity, what material would be safest for a crown?
Thank you for using the Health Physics Society's Ask the Experts feature. From a radiation safety point of view, both porcelain and zirconia crowns are safe. The amount of radioactivity in these crowns is small and in low concentrations, just like the amount of radioactivity that is naturally in your body.
For more details on porcelain crowns, let me refer you to a question and answer currently on our website: Question 8152. For more information on zirconia dental crowns, the following discussion was provided by Ron Kathren, CHP:
Zirconia-based dental crowns are used because of their many desirable mechanical strength characteristics, among others. Naturally occurring zirconium does not contain the isotope zirconium-84 (84Zr) but is a mixture of zirconium isotopes with mass numbers 90, 91, 92, 94, and 96. The 90, 91, 92, and 94 isotopes are stable (not radioactive). The 96 isotope, which accounts for 2.8% by weight of natural zirconium, is very weakly beta (but not alpha) radioactive, and its specific activity (radioactivity concentration) is so low that it can be considered negligible. Thus, the radiation dose from your zirconia crowns is, for all practical purposes, essentially zero and certainly nothing to be concerned about. Zirconia-based crowns are insoluble, and if swallowed, zirconium would not be absorbed into the body. Therefore, chemical toxicity is also of no concern.
Kent Lambert, CHP