Effects of pH and fluoride concentration of dentifrices on fluoride levels in saliva, biofilm, and biofilm fluid in vivo.

INTRODUCTION: Acidic dentifrices have been shown to be more effective than neutral ones against dental caries using in vitro, in situ, and clinical protocols. OBJECTIVES: Given the scarcity of studies assessing intraoral fluoride (F) retention after using such formulations, the present study evaluated the influence of pH and F concentration of dentifrices on F uptake by saliva, biofilm, and biofilm fluid. METHODS: Volunteers (n = 22) were randomly assigned to dentifrices containing 0 (placebo), 550 (LFD, low-fluoride dentifrice), and 1100 ppm F (CD, conventional dentifrice) at pH 4.5 and 7.0 and brushed their teeth 3 times/day following a double-blind, crossover protocol. Saliva and biofilm samples were collected after 7 days of using the dentifrices, 1 and approximately 12 h after last brushing. F and calcium (Ca) analyses were performed with the inverted electrode after buffering with TISAB III and the Arsenazo III method, respectively. Data were analyzed by 3-way ANOVA, Tukey's HSD test, and Pearson's correlation coefficient (p < 0.05). RESULTS: F concentrations in biofilm fluid and whole biofilm 1 h after brushing with acidic F-toothpastes were higher than those related to neutral counterparts, although the differences were small and not significant; no increases were observed in salivary F concentrations influenced by dentifrice pH. Moreover, no definite trend was observed for Ca concentrations in these compartments. CONCLUSION: Dentifrice pH had some influence on F uptake by the biofilm fluid, having lesser or no impact on F uptake by the biofilm and saliva, respectively. CLINICAL SIGNIFICANCE: Toothbrushing with acidic toothpastes leads to slight increases in F concentrations in the biofilm fluid when compared to neutral formulations, which may contribute to the higher anticaries effect of acidic formulations.

Fluoride concentrations of milk, infant formulae, and soy-based products commercially available in Brazil.

OBJECTIVES: To assess the fluoride (F) content in commercially available milk formulae in Brazil and to estimate the F intake in children from this source in the first year of life. METHODS: Samples of cow's milk (n = 51), infant formulae (n = 15), powdered milk (n = 13), and soy-based products (n = 4) purchased in Araçatuba (Brazil) had their F content measured using an ion-specific electrode, after hexamethyldisiloxane-facilitated diffusion. Powdered milk and infant formulae were reconstituted with deionized water, while ready-to-drink products were analyzed without any dilution. Using average infant body masses and suggested volumes of formula consumption for infants 1-12 months of age, possible F ingestion per body mass was estimated. Data were analyzed by descriptive analysis. RESULTS: Mean F content ranged from 0.02 to 2.52 mg/L in all samples. None of the cow's milk provided F intake higher than 0.07 mg/kg. However, two infant formulae, one powdered milk, and one soy-milk led to a daily F intake above the suggested threshold for fluorosis when reconstituted with deionized water. Assuming reconstitution of products with tap water at 0.7 ppm F, two infant formulae, five powdered milk, and four soymilks led to daily F intake ranging from 0.108 to 0.851 mg/kg. CONCLUSIONS: The results suggest that the consumption of some brands of infant formulae, powdered milk, and soy-based milk in the first year of age could increase the risk of dental fluorosis, reinforcing the need for periodic surveillance of the F content of foods and beverages typically consumed by young children.

Plaque fluoride concentrations associated to the use of conventional and low-fluoride dentifrices.

PURPOSE: This double-blind, crossover study evaluated whole plaque fluoride concentration (F), as well as whole plaque calcium concentrations (Ca) after brushing with a placebo (PD - fluoride free), low-fluoride (LFD, 513 microg F/g) and conventional (CD, 1,072 microg F/g) dentifrices. METHODS: Children (n=20) were randomly assigned to brush twice daily with one of the dentifrices, during 7 days. On the 7th day, samples were collected at 1 and 12 hours after brushing. F and Ca were analyzed with an ion-selective electrode and with the Arsenazo III method, respectively. Data were analyzed by ANOVA, Tukey's test and by Pearson correlation coefficient (P< 0.05). RESULTS: The use of the fluoridated dentifrices significantly increased plaque [F]s 1 hour after brushing when compared to PD, returning to baseline levels 12 hours after. Positive and significant correlations were found between plaque [F] and (Ca) under most of the conditions evaluated. The mean increase in plaque [F] observed 1 hour after brushing with the CD were only about 47% higher than those obtained for the LFD. The use of a LFD promotes proportionally higher increases in plaque [F] when compared to a CD. Plaque F concentrations were also shown to be dependent on plaque Ca concentrations.

Efeito do pH e da concentração de fluoreto presente em dentifrícios na incorporação de fluoreto pela saliva, biofilme e fluido do biofilme / Effect of pH and fluoride concentration in dentifrices on fluoride uptake by saliva, biofilm and biofilm fluid

O uso de fluoretos tem contribuído para o declínio da prevalência da cárie observado nas últimas décadas, porém um aumento na prevalência da fluorose dentária tem sido observado concomitantemente. Alternativas como a redução do pH e da concentração de fluoreto (F) dos dentifrícios têm sido estudadas na tentativa de melhorar a efetividade clínica dos mesmos, sem afetar sua eficácia anti-cárie. Considerando a escassez de estudos com metodologias in vivo avaliando a retenção intrabucal de F após a utilização de formulações aciduladas, o presente estudo avaliou a influência do pH e da concentração de fluoreto (F) de dentifrícios na retenção de F pela saliva, biofilme e fluido do biofilme. Voluntários (n=22) utilizaram dentifrícios contendo 0 (Placebo), 550 (DCRF – dentifrício com concentração reduzida de F) e 1100 ppm F (DC – dentifrício convencional), em pH 4,5 e 7,0, e escovaram seus dentes 3 vezes/dia seguindo um protocolo duplo-cego e cruzado. Amostras de saliva e biofilme dentário foram coletadas após 7 dias de uso dos dentifrícios, 1 e aproximadamente 12 horas após a última escovação. As análises de F e cálcio (Ca) foram realizadas com o eletrodo invertido após tamponamento com TISAB III e pelo método Arsenazo III, respectivamente. Os dados foram analisados por ANOVA fatorial, teste de Tukey HSD e coeficiente de correlação de Pearson (p<0,05). As concentrações de F no fluido do biofilme 1h após a escovação com o DCRF acidulado não diferiram das observadas para o DC neutro, sendo ambas significativamente mais altas que as obtidas com o placebo; este padrão, entretanto, não foi observado para o biofilme e saliva. Observou-se a ausência de um padrão definido para as concentrações de Ca nestes compartimentos, porém correlações significativas foram observadas entre as concentrações de F e Ca na saliva e no biofilme. De acordo com protocolo do estudo, concluiu-se que o pH influenciou na retenção de F no fluido do biofilme, tendo pouca ou nenhuma influência na...

The use of fluorides has contributed to the decline in caries prevalence observed in the last decades, however an increase in the prevalence of dental fluorosis has been observed concomitantly. Alternatives such as the reduction of the pH and fluoride (F) concentration of dentifrices have been studied as an attempt to improve their clinical effectiveness without affecting its anti-caries efficacy. Given the scarcity of in vivo studies assessing intraoral fluoride retention after using acidic formulations, the present study evaluated the influence of pH and F concentration of dentifrices on F uptake by saliva, biofilm and biofilm fluid. Volunteers (n = 22) used dentifrices containing 0 (Placebo), 550 (LFD – low-fluoride dentifrice) and 1100 ppm F (CD – conventional dentifrice) at pH 4.5 and 7.0, and brushed their teeth 3 times/day following a double-blind, crossover protocol. Saliva and dental biofilm samples were collected after 7 days of using the dentifrices, 1 and approximately 12 hours after last brushing. F and calcium (Ca) analysis were performed with the inverted electrode after buffering with TISAB III and the Arsenazo III method, respectively. Data were analyzed by factorial ANOVA, Tukey´s HSD test and Pearson´s correlation coefficient (p <0.05). F concentrations in the biofilm fluid 1h after brushing with acidic LFD were similar to those observed for neutral CD, both being significantly higher than values found for the Placebo; this pattern, however, was not observed for the biofilm and saliva. No defined trend was observed for Ca concentrations in these compartments, but significant correlations were observed between Ca and F concentrations in saliva and in the biofilm. According to the study protocol, it was concluded that pH influenced the uptake of F by the biofilm fluid, having little or no influence on the uptake by the biofilm and saliva, respectively