Retention of oral microorganisms on cobalt-chromium alloy and dental acrylic resin with different surface finishes

Statement of problem. The effect of surface finish of dental materials on the subsequent contamination by microorganisms. Purpose. This study compared the retention of Streptococcus oralis , Actinomyces viscosus , and Candida albicans on polished, sandblasted (fine and coarse) and electrobrightened cobalt-chromium alloy and dental acrylic resin to assess in vitro the effect of such techniques on prosthesis contamination. Material And Methods. Standardized cell suspensions were incubated with test materials for 1 hour at 37°C, after which retained cells were counted by using image analysis (percentage area of a microscopic field covered by cells). Results. Retention of bacterial cells was substantial ( S oralis 12% to 20% and A viscosus 9% to 16%) irrespective of surface finish. Maximal retention was observed on cobalt-chromium alloy that had undergone fine sandblasting and electrobrightening ( P