This study evaluated the antimicrobial effect of toothpastes containing 200 ppm fluoride (200F), xylitol (X, 16%), erythritol (E, 4%), and sodium trimetaphosphate (TMP, 0.25%), alone or in different associations, against Streptococcus mutans (SM), Lactobacillus casei (LC), Actinomyces israelii (AI), and Candida albicans (CA). Suspensions of the micro-organisms were added to a BHI Agar medium. Five wells were made on each plate to receive toothpaste suspensions at different dilutions. Toothpastes containing no actives (placebo) or 1100 ppm F (1100F) were used as negative and positive controls. Two-way ANOVA and Tukey’s HDS test were used (p < 0.05). For SM, the largest halo was for 200F+TMP at all dilutions, followed by the 200F+X+E toothpaste (p < 0.001). For LC, the overall trend showed that the polyols effectively inhibited microbial growth, and the association with the other compounds enhanced such effects (p < 0.001). For AI, a less-defined trend was observed. For CA, the experimental toothpaste (200F+X+E+TMP) was consistently more effective than the other treatments, followed by 200F+X+E (p < 0.001). The association of polyols and TMP in a low-fluoride toothpaste effectively reduced the growth of cariogenic micro-organisms (SM, CA, and LC), suggesting that this formulation could be an interesting alternative for children due to its low fluoride content.

This study aimed to evaluate the effect of hemoglobin (Hb) in combination with different concentrations of sodium trimetaphosphate (STMP) on initial enamel erosion in vitro. Ninety bovine enamel samples (4X4mm) were prepared and divided into six groups (n/group=15), according to the treatments: 1) Deionized water (negative control); 2) Commercial solution Elmex Erosion Protection® ; 3) 1.0 mg/mL Hb; 4) 1.0 mg/mL Hb+0.5% STMP; 5) 1.0 mg/mL Hb+1.0% STMP; 6) 1.0 mg/mL Hb+3.0% STMP. The samples were treated with the respective solutions (250µL, 2h, 37ºC, constant agitation), and the acquired enamel pellicle was formed for 2h using pooled stimulated human saliva. Subsequently, the samples underwent an erosive challenge with 0.01 M HCl (pH 2.3, for 10 seconds) to simulate intrinsic erosion. These procedures were performed once/day for 3 consecutive days. Demineralization was assessed by percentage surface hardness change (%SHC) and the relative surface reflection intensity (%SRI) by the Reflectometer Optipen. Data were analyzed by ANOVA and Tukey's tests (p < 0.05). The negative control exhibited significantly less protection for both variables compared to the other groups. Regarding %SHC, the most effective treatments were 1.0 mg/mL Hb + 0.5% STMP and 1.0 mg/mL Hb + 1.0% STMP, which surpassed all other groups, including the positive control. The best protection for %SRI was observed with 1.0 mg/mL Hb. These results suggest that combining Hb with an inorganic component may support the development of strategies to prevent intrinsic enamel erosion.

This in vitro study evaluated the effects of incorporating quercetin (QC) at varying concentrations (0.25%, 0.5%, and 1%) into a 35% hydrogen peroxide (H₂O₂) bleaching gel on esthetic outcomes, enamel hardness and roughness, and H₂O₂ transamelodentinal diffusion. Bovine enamel/dentin discs (n = 180; 12/per group for each analysis) were allocated into five groups: (1) negative control (NC), (2) 35% H₂O₂ (HP), (3) HP + 0.25% QC, (4) HP + 0.5% QC, and (5) HP + 1% QC. Treatments were applied for 40 min per session across three sessions with 7-day intervals. Color changes were evaluated using the CIELab* color system (ΔE_ab), with further analysis performed using the CIEDE2000 formula (ΔE₀₀) and the whitening index (ΔWI_D). Enamel surface hardness, roughness, cross-sectional hardness, and H₂O₂ diffusion were also evaluated. Data were analyzed using ANOVA, followed by the Student–Newman–Keuls test, with statistical significance set at p < 0.05. All experimental gels resulted in significant color changes (p < 0.001), with similar ΔE_ab, ΔE₀₀, and ΔWI_D across QC groups. The HP group showed greater reductions in hardness and increased roughness compared to others (p < 0.0001), while the HP/1%QC group resulted in no statistically significant alterations under the tested conditions. H₂O₂ diffusion was significantly greater in the HP group, while it was notably lower in the HP/1%QC group (p < 0.05). The incorporation of 1% quercetin into a 35% H₂O₂ gel maintains its bleaching efficacy while protecting enamel properties and reducing hydrogen peroxide diffusion. Quercetin-enriched H₂O₂ gels may enhance bleaching safety by protecting dental tissues while maintaining esthetic benefits.