In vitro colonisation of acrylic resin denture base materials by Streptococcus oralis and Actinomyces viscosus.

AIM: The aim of the study was to compare the attachment of two typical strains of oral bacteria to four denture base materials. DESIGN: In vitro study. METHOD: Discs of acrylic resin denture base materials (Paladon 65, polished and unpolished; Palapress; Microbase, polished and unpolished, and Triad VLC) were placed into Petri dishes with Schaedler's medium, inoculated with Streptococcus oralis 34 or Actinomyces viscosus T14V. MAIN OUTCOME MEASURES: After 24 h or 48 h the numbers of adhering bacteria were measured. RESULTS: The bacteria adhered to all discs in similar numbers: 3-9 x 10(6)/ml (viable cell count) and 9-22 x 10(8)/ml (total cell count) for T14V, and 2-6 x 10(6)/ml (viable cell count) and 1.5-3 x 10(8)/ml (total cell count) for 34. CONCLUSIONS: Polishing had little effect on adherence. Denture base materials are not resistant against adherence and possible surface damage by oral bacteria. Therefore, thorough oral hygiene is important for denture wearers.

Effect of three mouthrinses, containing amine/stannous fluoride, herbal extracts or Emser salt on the growth of oral bacteria--an in vitro study.

BACKGROUND/AIMS: Clinical studies have shown the efficacy of mouthrinses in reducing plaque accumulation and inflammation of oral tissues. The aim of this in vitro study was to compare the effect of three mouthrinses: Meridol, an organic amine/ stannous fluoride solution; Parodontax, containing herbal ingredients; and an 0.8 % Emser salt solution, on the growth of oral bacteria and dental plaque. METHODS: Growth of Actinomyces viscosus T14V, Capnocytophaga ochracea 25, C. sputigena 4, Actinobacillus actinomycetemcomitans (A.a.) Y4, and pooled supragingival plaque in the presence of the various mouthrinses, applied to paper discs, was tested in an agar diffusion test. In a second series of tests, the 4 bacterial strains were exposed to the agents for about 3 min to simulate rinsing, then the agent was removed, and the bacteria were inoculated into fresh nutrient broth. After 48 h bacterial growth was measured in a spectrophotometer and compared with the controls. RESULTS: In the agar diffusion test only Meridol, the organic amine/stannous fluoride-containing solution, could inhibit bacterial growth, except for A. a. Y4. When the bacteria where in contact with the agents for only a few minutes these results were confirmed. Neither Paradontax nor Emser salt inhibited the growth of the bacteria, and A. a. Y4 proved to be resistant to all three agents. Growth of the other three strains was inhibited by Meridol 92-99% (undiluted), 85-96% (1:5) and 83-98% (1:10). CONCLUSIONS: We conclude that only Meridol contains ingredients capable of inhibiting the growth of oral bacteria in vitro. The efficacy of the other two mouthrinses in reducing plaque accumulation in vivo has to be explained by other mechanisms.