Method: In this in vitro study, a seven-organism bacterial consortium (Streptococus mutans UA-159, Streptococcus gordonii DSM 6777, Fusobacterium nucleatum DSM 20482, Actinomyces naeslundii DSM 43013, Veillonella parvula DSM 2008, Lactobacillus casei DSM 20011 and Prevotella nigriscens DSM 13386) was grown on bovine dentine discs in a high-throughput active attachment model. Each strain was cultivated individually and purity-checked. For inoculum growth, 1x108 colony forming units of each strain was diluted in hog gastric mucin supplemented medium. 2 ml of the inoculum were placed in each well of a 24 polystyrene plate. The biofilms were exposed to sucrose 0.2% supplementation during 8 h per day and the remaining 16 hours without sucrose with medium being refreshed daily. Additionally, biofilms were submitted two times per day to following solution treatments: 5000 ppm F (A), 1100 ppm F (B) and placebo solution as a negative control (C). After 5 days of biofilm growth, dentine samples were assessed by transversal microradiography (TMR) and biofilm collected for bacterial counts. All experiments were done in triplicate.
Result: Overall microbiological counts decreased with increasing F concentration. The values (mean ± SD) of integrated mineral loss (IML, by TMR) for treatments A, B and C were respectively: 421.29 ± 33.80, 606.61 ± 103.30 and 1390.54 ± 198.82. Tukey post-ANOVA test showed statistical differences among all treatment groups, with lower IML values observed when treatment A was used in comparison with the other treatments (p<0.05).
Conclusion: The 5000 ppm F solution caused a shift in microbial composition and reduced the dentin demineralization in this in vitro experimental model.