title: In vitro study of transmission of bacteria from contaminated metal models to stone models via impressions.
abstract: The purpose of this study was to determine the risk of microbiological transmission into the dental laboratory via impressions and dental stone models. Metal master models were contaminated with Bacillus subtilis and Streptococcus sanguis. Impressions in alginate, polyvinylsiloxane, and polyether were used, and models were cast in two brands of dental stone. Samples were taken from the impression surfaces before and after casting, and sections from the stone models were taken by a technique developed for this study. After incubation, the numbers of colonies were counted and the numbers of colony-forming units per milliliter were calculated. The reductions were statistically significant but considered to be clinically insignificant. The conclusion is that even after severe contamination, the risks to dental laboratory personnel are minimal. "Normal" hygienic procedures are recommended instead of disinfection.
authors.affiliation: Department of Removable Prosthodontics, Dental School, Aristotle University, Thessaloniki, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Sofou
authors.forename: T
authors.initials: T
authors.lastname: Larsen
authors.forename: B
authors.initials: B
authors.lastname: Owall
authors.forename: N-E
authors.initials: NE
authors.lastname: Fiehn
mesh_terms: D000464:Alginates; D001412:Bacillus subtilis / Q000302:isolation & purification / Q000502:physiology; D002133:Calcium Sulfate; D015169:Colony Count, Microbial; D003722:Dental Alloys; D003734:Dental Casting Investment; D003735:Dental Casting Technique; D003760:Dental Impression Materials; D003761:Dental Impression Technique / Q000295:instrumentation; D004866:Equipment Contamination; D006801:Humans; D007754:Laboratories, Dental; D003765:Models, Dental / Q000382:microbiology*; D011145:Polyvinyls; D012117:Resins, Synthetic; D012307:Risk Factors; D012833:Siloxanes; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D013298:Streptococcus sanguis / Q000302:isolation & purification / Q000502:physiology
chemical_list: D000464:Alginates; D003722:Dental Alloys; D003734:Dental Casting Investment; D003760:Dental Impression Materials; C022821:Impregum; D011145:Polyvinyls; D012117:Resins, Synthetic; D012833:Siloxanes; C034183:vinyl polysiloxane; D013193:Stainless Steel; D002133:Calcium Sulfate