Effect of TiF4/NaF and chitosan solutions on biofilm formation and prevention of dentin demineralization

Objective: This study evaluated the effect of experimental solutions containing TiF4/NaF and chitosan on bacterial species of microcosm biofilm and on dentin demineralization. Design: Microcosm biofilm was produced from human saliva mixed with McBain medium (0.2% sucrose) on bovine dentin for 5 days, under 5% CO2 and 37 degrees C. From the 2nd day to 5th day, the treatments were applied (1 x 60s/day) as following: (1) NaF (500 ppm F-, positive control); (2) TiF4 and NaF (TiF4: 190 ppm Ti4+ and 300 ppm F-; NaF: 190 ppm F-); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation). CFU counting was performed for total microorganism, total streptococci, total lactobacilli and mutans streptococci. Dentin demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < 0.05). Results: No differences were found between the treatments with respect to CFU counting (p > 0.05). Dentin treated with TiF4/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF4/NaF solution, being both able to significantly reduce mineral loss. Conclusion: TiF4/NaF plus chitosan solution, at suitable pH to be clinically applicable, had no antimicrobial effect, but it was able to reduce dentin caries development under this model.