title: Genotoxic effects of X-rays on keratinized mucosa cells during panoramic dental radiography.
abstract: OBJECTIVE
  The aim of this study was to evaluate the genotoxic effects of X-rays on epithelial gingival cells during panoramic dental radiography using a differentiated protocol for the micronucleus test.
  
  
  METHODS
  40 healthy individuals who underwent this procedure for diagnostic purposes on request from their dentists agreed to participate in this study. All of them answered a questionnaire before the examination. Epithelial gingival cells were obtained from the keratinized mucosa of the upper dental arcade by gentle scraping with a cervical brush immediately before exposure and 10 days later. Cytological preparations were stained according to the Feulgen-Rossenbeck reaction, counterstained with fast green 1% for 1 min and analysed under a light microscope. Micronuclei, nuclear projections (broken eggs) and degenerative nuclear alterations (pyknosis, karyolysis, karyorrhexis and condensed chromatin) were scored.
  
  
  RESULTS
  The frequency of micronuclei was significantly higher after exposure (P < 0.05), as were the frequencies of nuclear alterations indicative of apoptosis (P < 0.001).
  
  
  CONCLUSIONS
  These results indicate that X-ray radiation emitted during panoramic dental radiography induces a genotoxic effect on epithelial gingival cells that increases the frequency of chromosomal damage and nuclear alterations indicative of apoptosis.
authors.affiliation: Av. Princesa Isabel 114, Apto 602, Porto da Barra, Salvador, Bahia, CEP 40140-000 Brazil. eneida.cerqueira@gmail.com
authors.forename: E M M
authors.initials: EM
authors.lastname: Cerqueira
authors.forename: J R C
authors.initials: JR
authors.lastname: Meireles
authors.forename: M A
authors.initials: MA
authors.lastname: Lopes
authors.forename: V C
authors.initials: VC
authors.lastname: Junqueira
authors.forename: I S
authors.initials: IS
authors.lastname: Gomes-Filho
authors.forename: S
authors.initials: S
authors.lastname: Trindade
authors.forename: G M
authors.initials: GM
authors.lastname: Machado-Santelli
mesh_terms: D000328:Adult; D002467:Cell Nucleus / Q000528:radiation effects; D002875:Chromosomes / Q000528:radiation effects; D004249:DNA Damage; D005260:Female; D006801:Humans; D015603:Keratinocytes / Q000528:radiation effects*; D008297:Male; D015162:Micronucleus Tests; D009061:Mouth Mucosa / Q000166:cytology / Q000528:radiation effects*; D011862:Radiography, Panoramic / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D014965:X-Rays / Q000009:adverse effects; D055815:Young Adult