Early antibacterial effect of Pd-Ag dental alloy on aerobic and microaerophilic flora in oral cavity

Early effect of Pd-Ag alloy on aerobic and microaerophilic flora from healt hy oral cavity was studied. Normal microbial flora was sampled from saliva, dental plaque and gingival crevice from healthy individuals without any pr osthodontic appliances or periodontal diseases. Such samples were inoculate d into liquid media and were left in thermostat (37 degrees C) in aerobic c ondition. In some samples one or two sterile Pd-Ag alloy pieces were inocul ated, while some samples were left without that pieces to be a control grou p. Both were kept in a thermostat for 24 and 48 hrs and after that were exa mined for bacterial dehydrogenic activity to reveal the amount of active ba cteria in a sample. Dehydrogenic activity was registered after incubation o f 0.1 mi of 3-phenyltetrazolynchloryde (TTC) into samples. TCC changes a co lour of a liquid media because of bacterial dehydrogenic activity and there fore samples were analysed in a spectroscope. Statistical analysis revealed Lower bacterial activity (lower TTC distinction) in samples with one or tw o Pd-Ag alloy pieces than in a control group. These results indicate the ex istence of initial inhibitory effect of Pd-Ag alloys on aerobic flora in, t he mouth, which might give space for anaerobic strains to increase their gr owth. Presence of periodontal changes in a gingival crevice with Pd-Ag allo y crowns is probably due to anaerobic micro-organisms, as mostly anaerobic strains are responsible for periodontal disease.