IADR Abstract Archives
Caries-Preventive Effect of Fluoride and Fluoride+Chlorhexidine Varnishes In-vitro
Objectives: The aim of our study was to compare the preventive effect of fluoride varnish and fluoride varnish containing chlorhexidine on root caries formation.
Methods: 100 bovine root dentine samples were allocated to five treatment groups (n=20/group): (1) fluoride (7700 ppm) varnish (FP), (2) placebo varnish for FP (FP-P), (3) chlorhexidine (0.3%) + fluoride (1400 ppm) varnish (CF), (4) placebo varnish for CF (CF-P), (5) untreated control. A carious challenge was provided using a multi-station, continuous-culture 3-species (Streptococcus mutans (SM), Lactobacillus rhamnosus (LR), Actinomyces naeslundii (AN)) biofilm model. Bacteria were inoculated 1× daily, followed by provision of 1% sucrose 5× daily and artificial saliva after each sucrose pulse. After 10 days, mineral loss (ΔZ) was measured in the effect area and adjacent to the varnished areas, and bacterial counts of the biofilms on the varnished areas were assessed. Three-dimensional biofilm architecture of exemplary specimens from the FP-, CF- and control-groups was analyzed via fluorescence in situ hybridization (FISH) and confocal microscopy.
Results: Mean±SD ΔZ was significantly lower for FP (9133±758 vol%×μm) and CF (9835± 1677) compared to the control-group (11363±919; p<0.05/ANOVA), with no significant difference between FP and CF. Varnishes did not protect adjacent areas against demineralization and placebo varnishes had no significant preventive effect on ΔZ. SM counts were significantly lower in FP- and CF-biofilms than controls, while LR counts were significantly higher in FP- and CF-biofilms. AN counts were significantly higher in the FP-group compared to all other groups. FISH demonstrated the presence of thick biofilms containing all employed bacteria. SM and LR invaded dentinal tubules, but only in the control-group. In the CF-group, the basal biofilm layer contained only LR.
Conclusions: FP and CF had a similar caries-preventive effect. Both varnishes have a considerable impact on biofilm structure and composition, with only minor differences between these varnishes.
Methods: 100 bovine root dentine samples were allocated to five treatment groups (n=20/group): (1) fluoride (7700 ppm) varnish (FP), (2) placebo varnish for FP (FP-P), (3) chlorhexidine (0.3%) + fluoride (1400 ppm) varnish (CF), (4) placebo varnish for CF (CF-P), (5) untreated control. A carious challenge was provided using a multi-station, continuous-culture 3-species (Streptococcus mutans (SM), Lactobacillus rhamnosus (LR), Actinomyces naeslundii (AN)) biofilm model. Bacteria were inoculated 1× daily, followed by provision of 1% sucrose 5× daily and artificial saliva after each sucrose pulse. After 10 days, mineral loss (ΔZ) was measured in the effect area and adjacent to the varnished areas, and bacterial counts of the biofilms on the varnished areas were assessed. Three-dimensional biofilm architecture of exemplary specimens from the FP-, CF- and control-groups was analyzed via fluorescence in situ hybridization (FISH) and confocal microscopy.
Results: Mean±SD ΔZ was significantly lower for FP (9133±758 vol%×μm) and CF (9835± 1677) compared to the control-group (11363±919; p<0.05/ANOVA), with no significant difference between FP and CF. Varnishes did not protect adjacent areas against demineralization and placebo varnishes had no significant preventive effect on ΔZ. SM counts were significantly lower in FP- and CF-biofilms than controls, while LR counts were significantly higher in FP- and CF-biofilms. AN counts were significantly higher in the FP-group compared to all other groups. FISH demonstrated the presence of thick biofilms containing all employed bacteria. SM and LR invaded dentinal tubules, but only in the control-group. In the CF-group, the basal biofilm layer contained only LR.
Conclusions: FP and CF had a similar caries-preventive effect. Both varnishes have a considerable impact on biofilm structure and composition, with only minor differences between these varnishes.