Reduction in erosive tooth wear using stannous fluoride-containing dentifrices: a meta-analysis

Effects of the application timing of anti-erosive agents on dentin erosion

This in vitro study aimed to evaluate the effects of the application timing of anti-erosive agents on dentin erosion. Eighty dentin specimens with dimensions of 2 × 2 × 2 mm were prepared and randomly divided into 4 groups based on the treatment solutions: 1.23 × 104 μg/ml sodium fluoride (NaF), 120 μg/ml chlorhexidine (CHX), 300 μg/ml quercetin (QUE), and deionized water (DW, negative control). The specimens in each group were further divided into 2 subgroups according to the application timing of the treatment solutions (n = 10): before the erosive challenges (PRE) and after the erosive challenges (POST). All specimens were submitted to 4 daily erosive challenges for 5 d. For each erosive challenge, the specimens in the subgroup PRE were treated with the respective solutions for 2 min and then immersed in cola drinks for 5 min, while the specimens in the subgroup POST were immersed in cola drinks for 5 min followed by treatment with the respective solutions for 2 min. The erosive dentin loss (EDL) was measured using a contact profilometer, and the surface morphology of the dentin specimens was evaluated by scanning electron microscopy at the end of the experiment. The data were statistically analyzed using two-way analysis of variance (ANOVA) and Bonferroni's test (α = 0.05). Significantly less EDL was observed in the groups NaF, CHX, and QUE than in the group DW (all P < 0.001). Significantly lower EDL was observed in the groups CHX and QUE than in the group NaF (P = 0.001 and P < 0.001, respectively). For CHX, subgroup POST exhibited significantly less EDL than subgroup PRE (P < 0.001). Regarding QUE, subgroup PRE showed significantly less EDL than subgroup POST (P < 0.001). Furthermore, a relatively greater number of obliterated dentinal tubules was visible in the subgroup POST rather than in the subgroup PRE of the group CHX, while in the group QUE, narrower dentinal tubules were observed in the subgroup PRE than those in subgroup POST. In conclusion, CHX and QUE showed the best performance in controlling dentin erosion. CHX was more effective in reducing EDL when applied after erosive challenges, whereas QUE worked more effectively when used before erosive attacks. The application timing should be considered when evaluating the effects of anti-erosive agents because it may determine their effectiveness.

Effect of a Stannous Fluoride Dentifrice on Biofilm Composition, Gene Expression and Biomechanical Properties

An in situ study was conducted to examine the mode of action of a 0.454% stannous fluoride (SnF₂)-containing dentifrice in controlling the composition and properties of oral biofilm. Thirteen generally healthy individuals participated in the study. Each participant wore an intra-oral appliance over a 48-h period to measure differences in the resulting biofilm’s architecture, mechanical properties, and bacterial composition after using two different toothpaste products. In addition, metatranscriptomics analysis of supragingival plaque was conducted to identify the gene pathways influenced. The thickness and volume of the microcolonies formed when brushing with the SnF₂ dentifrice were dramatically reduced compared to the control 0.76% sodium monofluorophosphate (MFP)-containing toothpaste. Similarly, the biophysical and nanomechanical properties measured by atomic force microscopy (AFM) demonstrated a significant reduction in biofilm adhesive properties. Metatranscriptomic analysis identified pathways associated with biofilm formation, cell adhesion, quorum sensing, and N-glycosylation that are significantly downregulated with SnF₂. This study provides a clinically relevant snapshot of how the use of a stabilized, SnF₂ toothpaste formulation can change the spatial organization, nanomechanical, and gene expression properties of bacterial communities.