Sound evidence on the effectiveness of fluoride varnishes (FV) to reduce caries incidence in preschool children is lacking. Objective: To assess whether the application of FV in preschool children at 6-month intervals decreases the incidence of caries and produces any adverse effects. Methods: A randomized, examiner- and patient-blind, placebo-controlled, parallel-group design, clinical trial, comprising 1- to 4-year-old children, 100 in each group (FV or placebo varnish, PV), was conducted in Rio de Janeiro, Brazil. Two trained pediatric dentists performed the clinical examinations (kappa = 0.85). Dental caries was recorded at the d₂ (cavitated enamel) and d₃ (dentine) levels using the International Caries Diagnosis and Assessment System. Results: At baseline, the mean age of the participants was 2.4 years (SD 0.9) and the mean d₃mfs was 0.8 (SD 1.9). Most of the children brushed their teeth with fluoride toothpaste and consumed fluoridated tap water. After 24 months, 89 and 92 children of the test and the control groups were analyzed, respectively. A total of 32 (35.9%) children in the FV group and 43 (46.7%) in the PV group presented new dentine caries lesions (χ² test; p = 0.14), showing relative and absolute risk reductions of 23% (95% CI: -9.5 to 45.9) and 11% (95% CI: -3.5 to 25.0). The mean caries increment differences between the test and control groups were -0.8 (95% CI: -2.0 to 0.4) at the d₂ level and -0.7 (95% CI: -1.9 to 0.4) at the d₃ level. Only 2 minor complaints regarding the intervention were reported. Conclusion: Although safe and well accepted, twice-yearly professional FV application, during 2 years, did not result in a significant decrease in caries incidence.

Depending on toothpaste formulation, part of the fluoride is insoluble and would not be totally absorbable in the gastrointestinal tract, thus changing dental fluorosis risk estimation. This hypothesis was tested with formulations with either all fluoride in a soluble form (NaF/SiO₂-based toothpaste, 1,100 µg F/g as labeled, 1,129.7 ± 49.4 µg F/g soluble fluoride as analyzed) or with around 20% of insoluble fluoride (Na₂FPO₃/CaCO₃-based toothpaste, 1,450 µg F/g as labeled, 1,122.4 ± 76.4 µg F/g soluble fluoride as analyzed). Toothpastes were evaluated either fresh or after accelerated aging, which increased insoluble fluoride to 40% in the Na₂FPO₃/CaCO₃-based toothpaste. In a blind, crossover clinical trial conducted in five legs, 20 adult volunteers ingested 49.5 µg of total fluoride/kg body weight from each formulation or purified water (control). Whole saliva and urine were collected as bioavailability indicators, and pharmacokinetics parameters calculated showed significantly (p < 0.05) lower fluoride bioavailability for Na₂FPO₃/CaCO₃ toothpaste, which was reduced further after aging. A significant correlation between the amount of soluble fluoride ingested, but not total fluoride, and fluoride bioavailability was found (r = 0.57, p < 0.0001). The findings suggest that the estimated fluorosis risk as a result of ingestion of Na₂FPO₃/CaCO₃-based toothpastes should be calculated based on the toothpaste’s soluble rather than total fluoride concentration.

The aim of this study was to analyze the antimicrobial activity and substantivity of Uncaria tomentosa Willd DC (cat's claw, CC) in root dentin contaminated with Enterococcus faecalis. Forty-eight human premolars were contaminated with E. faecalis (ATCC 29212) and randomly divided into four groups according to the irrigant used during chemomechanical preparation (CMP): CC group: 2% CC gel; CHX group: 2% chlorhexidine digluconate gel (CHX); NaOCl group: 5.25% sodium hypochlorite (NaOCl); and SS group: sterile saline (SS). Microbiological samples were collected before (S1) and after (S2) CMP and after 7 days (S3). Colony-forming units (CFU/mL) at the different sampling times and comparisons among the groups were statistically analyzed by Wilcoxon and Kruskal-Wallis tests (p < 0.05). Significant bacterial reduction was achieved in all groups after CMP (p < 0.05). Results show no significant difference between S3 and S2 (p > 0.05) in the CC and CHX groups. Bacterial load was higher in S3 than in S2 samples (p < 0.05) in the NaOCl and SS groups. Our results suggest antibacterial effect of 2% CC gel against E. faecalis in infected dentin, in addition to antibacterial substantivity of 2% CC and 2% CHX up to 7 days.

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Calcium fluoride-like materials ("CaF 2 ") formed on dental surfaces after professional fluoride application are unstable in the oral environment but can be retained longer with a daily NaF mouthrinse. We tested the effect of twice daily 0.05% NaF rinses on the retention of "CaF 2 " formed on enamel and dentine after applying acidulated phosphate fluoride (APF). "CaF 2 " formed on enamel/dentine by APF application significantly decreased after exposure to artificial saliva and the 0.05% NaF rinse was ineffective to avoid this reduction. These findings suggest that the combination of APF and 0.05% NaF is not clinically relevant, either for caries or dental hypersensitivity.