title: Disinfection of bacterially contaminated hydrophilic PVS impression materials.
abstract: OBJECTIVE
  This study evaluated disinfection of bacterially contaminated hydrophilic polyvinylsiloxane (PVS) and polyether impressions.
  
  
  METHODS
  Four light-bodied PVS (Examix, Genie, Take 1, Aquasil) and one polyether (Impregum) impression materials were evaluated using three disinfectants (EcoTru [EnviroSystems], ProSpray [Certol], and bleach [diluted 1:9]) as spray and immersion disinfections for 10-minute exposures. Pseudomonas aeruginosa ATCC 15442, Salmonella choleraesius ATCC 10708, and Staphylococcus aureus ATCC 6538 was the microbial challenge. Test specimens were prepared using aluminum molds with ten tapered cones. Mucin covered each cone, followed by 0.01 mL of each bacterium. Impressions were made using low viscosity impression material that was injected over the cones and filled custom trays. One-half of the impressions were spray disinfected, while the others underwent immersion disinfection. Trays that were contaminated but not disinfected served as positive controls, while those not bacterially contaminated or disinfected served as negative controls. The impressions were poured with Silky Rock Die Stone, and after setting, two cones were placed within a sterile capsule and triturated into powder. Four milliliters of TRIS buffer (0.05 M, pH 7.0) containing sodium thiosulfate (0.0055% w/v) were poured in each tube. After mixing, the solution was serially diluted and spread-plated onto selective agars. After incubation, colony counting occurred.
  
  
  RESULTS
  No viable bacteria transferred to casts from either spray- or immersion-disinfected impressions. Negative controls produced no microbial colonies. Positive controls produced on average 3.35 × 10(5) bacterial cells.
  
  
  CONCLUSIONS
  Results suggest the methods used could disinfect contaminated impression materials. Microbial transfer from nondisinfected impressions to cones approached 33.5%.
authors: Department of Prosthodontics, University of Iowa College of Dentistry, Iowa City, IA 52242, USA. emad-estafanous@uiowa.edu
authors: Emad Wadie
authors: EW
authors: Estafanous
authors: Charles John
authors: CJ
authors: Palenik
authors: Jeffrey A
authors: JA
authors: Platt
mesh_terms: D019551:Dental Disinfectants / Q000737:chemistry / Q000494:pharmacology*; D003760:Dental Impression Materials; D004203:Disinfection / Q000379:methods*; D004987:Ethers; D057927:Hydrophobic and Hydrophilic Interactions; D003765:Models, Dental / Q000382:microbiology; D011145:Polyvinyls; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012475:Salmonella / Q000187:drug effects; D012833:Siloxanes; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D019551:Dental Disinfectants; D003760:Dental Impression Materials; D004987:Ethers; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane