[Research on inhibition of sodium fluoride on five subgingival bacteria in vitro]

This in vitro study was aimed at observing inhibition action of fluoride on 5 common periodontal bacteria in subgingival microflora. The liquid media two-fold dilution method was used to determine the minimal inhibition concentration (MIC) of sodium fluoride (NaF) to 9 strains of bacteria representing the main periodontopathic species(P. gingivalis, A. actinomycetemcomitans, P. intermedius) and the periodontal beneficial species (S. sanguis) and 1 strain of S. sorbrinus. The results showed that all the bacteria were inhibited at different concentration of NaF. The MIC values ranged from 128 micrograms/ml for P. gingivalis and A. actinomycetemcomitans, 256 micrograms/ml for S. sorbrinus, 1024 micrograms/ml for P. intermedius to 2048-4096 micrograms/ml for S. sanguis. The results suggest that NaF can also be used as a periodontal anti-bacterium agent and those preparations containing about 1000 micrograms/ml fluoride can be used effectively against the periodontopathic bacteria without disturbing the local ecological balance.