title: Historical background to radiation safety of dental x-ray sets in the English speaking countries.
mesh_terms: D001315:Australia; D002170:Canada; D049673:History, 20th Century; D009520:New Zealand; D011835:Radiation Protection; D011861:Radiography, Dental; D011871:Radiology / Q000266:history*; D013019:South Africa; D006113:United Kingdom; D014481:United States