No abstract

The contamination level of alginate impressions delivered to a large dental laboratory in Sweden was determined. One hundred and seven consecutive alginate impressions were included during 7 days. Samples were taken and transferred into sterile physiological saline and analysed microbiologically for colony-forming units (cfu) as well as nonhemolytic, α-hemolytic, and β-hemolytic colonies. After sampling, the clinics were contacted and asked to fill in simple questionnaires about their routines of disinfecting impressions. The questionnaire study revealed that about half of the clinics had some kind of disinfection routine, while the others rinsed in running water only. Seventy-two percent of the impressions yielded growth of bacteria, with a median number of 1.3×10 2 cfu. Thirteen per cent of the samples yielded >10 3 cfu, with a maximum number of 3.4×10 4 cfu. The majority of isolates were non-and α-hemolytic bacteria. Growth was recorded in 61.3% of disinfected impressions, and the numbers of bacteria in disinfected and nondisinfected impressions were similar. These findings raise the question of whether impressions need to be disinfected or if proper handling and hygienic procedures are sufficient to block the possible route of infection.

No abstract

According to the results of the study, patients' overall acceptance of their newly constructed complete dentures improved significantly for both groups (traditional and duplication construction protocols). Study participants adapted dissimilarly to their newly constructed complete dentures regarding comfort, as assessed by the total number of sore spots, although the recorded mean number of initial adaptation/adjustment visits was equal.

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.