title: Decreases in occupational exposure to ionizing radiation among Canadian dental workers.
abstract: OBJECTIVE
  To describe doses of ionizing radiation and their possible associations with mortality rates and cancer incidence among Canadian dental workers.
  
  
  METHODS
  The National Dose Registry (NDR) of Canada was used to assess occupational dose of ionizing radiation received by dental workers. The NDR cohort includes 42,175 people classified as dental workers. Subjects in the NDR were linked to both the Canadian Mortality Database and the Canadian Cancer Database to ascertain cause of death and cancer incidence, respectively.
  
  
  RESULTS
  The cohort consisted of 9,051 male and 33,124 female dental workers. A total of 656 incident cases of cancer and 558 deaths were observed. The standardized mortality ratio associated with all-cause mortality was 0.53 (90% confidence interval [CI] 0.49-0.57). The incidence of cancer among dental workers was lower than that for the Canadian population for all cancers except melanoma of the skin (for melanoma, the standardized incidence ratio was 1.46 [90% CI 1.14-1.85]). Occupational doses of ionizing radiation among dentists and dental workers have decreased markedly since the 1950s.
  
  
  CONCLUSIONS
  Dental workers receive very low doses of ionizing radiation, and these doses do not appear to be associated with any increase in cancer incidence; the increased incidence of melanoma is more likely related to other risk factors such as exposure to ultraviolet radiation from sunlight.
authors.affiliation: Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Zielinski
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Garner
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
authors.forename: J Patrick
authors.initials: JP
authors.lastname: Ashmore
authors.forename: Pierre R
authors.initials: PR
authors.lastname: Band
authors.forename: Martha E
authors.initials: ME
authors.lastname: Fair
authors.forename: Huixa
authors.initials: H
authors.lastname: Jiang
authors.forename: Ernest G
authors.initials: EG
authors.lastname: Letourneau
authors.forename: Robert
authors.initials: R
authors.lastname: Semenciw
authors.forename: Willem N
authors.initials: WN
authors.lastname: Sont
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D002423:Cause of Death; D015331:Cohort Studies; D003797:Dental Staff; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D016273:Occupational Exposure / Q000009:adverse effects*; D011829:Radiation Dosage; D011861:Radiography, Dental / Q000009:adverse effects*