Estabilidade de fluoretos em enxaguatórios com produtos naturais: estudo in vitro

Abstract

The study aimed to monitor the physicochemical stability and sodium fluoride (NaF) sequestration, as well as determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against *Streptococcus mutans* (INCQS00446) in natural extracts and commercial herbal mouthwashes. This in vitro study analyzed parameters such as pH, fluoride concentration, turbidity, and phase/color alterations. Samples were prepared from a 200 mg/L NaF solution to achieve 10 mg/L NaF in five mouthwashes (Água Rabelo® Traditional, Pomegranate, Ginger, Citrus, and Aloe Vera). Five plant extracts (1.5 g; Eucalyptus, Pomegranate, Ginger, Peppermint, and Brazilian Pepper Tree) were solubilized in deionized water, Tween 80, DMSO, and NaF to reach 10 mg/L NaF. Fluoride analysis was conducted using potentiometry with standard solutions (0.5–10 ppm F) and TISAB II. Samples were stored for two months at 25°C (ambient) and accelerated aging temperatures (37°C and 45°C). FluorPlax (0.05% fluoride) served as the control group. Results indicated a gradual loss of free fluoride in commercial mouthwashes, ranging from 14.18 ppm F (Aloe Vera at ambient temperature, week 6) to 0.96 ppm F (Citrus at 37°C, week 8). For plant extracts, fluoride levels varied from 2.50 ppm F (Brazilian Pepper Tree at ambient temperature, week 5) to 12.65 ppm F (Eucalyptus at 37°C, week 2). pH exhibited acidic tendencies over time and across temperatures. Microbiological analysis showed an additive effect between fluoride and Água Rabelo® Ginger, as well as between fluoride and natural extracts. Findings highlight that incorporating fluoride into herbal mouthwashes requires pharmaceutical or biotechnological adjustments to minimize fluoride interactions with organic functional groups. Identifying and eliminating fluoride-sequestering constituents is essential, alongside optimized fluoride incorporation, to achieve effective dental remineralization and antimicrobial activity.