title: Genetic damage in human peripheral lymphocytes exposed to antimicrobial endodontic agents.
abstract: OBJECTIVE
  Formocresol, paramonochlorophenol, or calcium hydroxide have been widely used in dental practice to eradicate bacteria and consequently to produce root canal disinfection. Taking into consideration strong evidence for a relationship between DNA damage and carcinogenesis, the purpose of the present study was to evaluate the genotoxic effects of antimicrobial endodontic compounds in human peripheral lymphocytes by single-cell gel (comet) assay. This technique detects DNA strand breaks in individual cells.
  
  
  METHODS
  A total of 10 microL of the tested substance solution (formocreso1, paramonochlorofeno1, and calcium hydroxide at 100-microg/mL concentration) was added to human peripheral lymphocytes from 10 volunteers for 1 hour at 37 degrees C. The negative control group was treated with vehicle control (PBS) for 1 hour at 37 degrees C, as well. For the positive control group, lymphocytes were exposed to hydrogen peroxide at 100 microM during 5 minutes on ice.
  
  
  RESULTS
  No DNA breakage was detected after a treatment of peripheral lymphocytes by formocresol, paramonochlorophenol, or calcium hydroxide at 100 microg/mL.
  
  
  CONCLUSIONS
  In summary, our results indicate that exposure to formocresol, paramonochlorophenol, or calcium hydroxide may not be a factor that increases the level of DNA lesions in human peripheral lymphocytes as detected by single-cell gel (comet) assay.
authors.affiliation: Department of Pathology, Botucatu Medical School, Sao Paulo State University, Sao Paulo, Brazil.
authors.forename: Glenda N
authors.initials: GN
authors.lastname: Da Silva
authors.forename: Elaine A
authors.initials: EA
authors.lastname: De Camargo
authors.forename: Daisy M F
authors.initials: DM
authors.lastname: Salvadori
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Ribeiro
mesh_terms: D000328:Adult; D000891:Anti-Infective Agents, Local / Q000633:toxicity*; D002126:Calcium Hydroxide / Q000633:toxicity; D002478:Cells, Cultured; D002733:Chlorophenols / Q000633:toxicity; D020552:Comet Assay; D004249:DNA Damage; D005260:Female; D005566:Formocresols / Q000633:toxicity; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects*; D008297:Male; D012388:Root Canal Irrigants / Q000633:toxicity*
chemical_list: D000891:Anti-Infective Agents, Local; D002733:Chlorophenols; D005566:Formocresols; D012388:Root Canal Irrigants; C031025:formocresol; C029107:4-chlorophenol; D002126:Calcium Hydroxide