title: Disinfection of irreversible hydrocolloid impression material with chlorinated compounds.
abstract: OBJECTIVE
  Irreversible hydrocolloid (alginate) impressions are dimensionally unstable and difficult to disinfect.
  
  
  OBJECTIVE
  To evaluate the antimicrobial efficacy of a chlorite disinfectant (Presept) and a new formulation chlorine dioxide based disinfectant (Aseptrol) on irreversible hydrocolloid (alginate) impression material.
  
  
  METHODS
  Alginate blocks were contaminated with Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans and Bacillus subtilis spores. The blocks were placed either in sterile distilled water as control, or in 48-ppm Aseptrol or Presept solution containing organic matter. Immersion times were 30 seconds, 1, 1.5, 2, 3 and 5 minutes. The blocks were then placed in sterile 0.5% sodium thiosulphate neutralizer and surviving organisms were harvested and counted using the serial dilution technique followed by culturing on appropriate media. The anti-microbial efficacy of the solution was tested for 37 days.
  
  
  RESULTS
  There was a consistent significant reduction (99.99%) in all tests of vegetative organisms after immersion in the Aseptrol for 30 seconds, and for spores after 1.5 minutes. It was effective against vegetative organisms for up to 27 days for a 30-second exposure. Presept significantly reduced (99.99%) C. albicans, S. aureus and S. mutans in 30 seconds, P. aeruginosa in 60 seconds, but for B. subtilis spores took at least 5 minutes. It was effective against vegetative organisms for >37 days for a 30-second exposure.
  
  
  CONCLUSIONS
  Within the limits of this study it was found that both compounds effectively disinfected the alginate in the presence of organic material, but that Aseptrol did so after an immersion time of only 1.5 minutes. This immersion time is less likely to affect the dimensional properties of the impression material.
  
  
  CONCLUSIONS
  The short action time of Aseptrol may make it ideal for the disinfection of alginate impressions, and it may also find many uses for disinfection and possible sterilisation.
authors.affiliation: Department of Prosthodontics, School of Oral Health Sciences, University of the Witwatersrand, Johannesburg.
authors.forename: I H
authors.initials: IH
authors.lastname: Rweyendela
authors.forename: M
authors.initials: M
authors.lastname: Patel
authors.forename: C P
authors.initials: CP
authors.lastname: Owen
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects; D017606:Chlorine Compounds / Q000494:pharmacology; D015169:Colony Count, Microbial; D019551:Dental Disinfectants / Q000494:pharmacology*; D003760:Dental Impression Materials / Q000737:chemistry*; D004203:Disinfection / Q000379:methods*; D006801:Humans; D008422:Materials Testing; D010087:Oxides / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013171:Spores, Bacterial / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects; D013499:Surface Properties; D013997:Time Factors; D014227:Triazines / Q000494:pharmacology
chemical_list: D000464:Alginates; D000890:Anti-Infective Agents; D017606:Chlorine Compounds; D019551:Dental Disinfectants; D003760:Dental Impression Materials; D010087:Oxides; D014227:Triazines; C025109:chlorine dioxide; C011765:troclosene