Fluoride content in children's dentifrices marketed in Lima, Peru.

The aim of the present study was to determine the concentration of total fluoride (TF) and total soluble fluoride (TSF) in children's dentifrices marketed in the city of Lima, Peru. Three samples of 23 dentifrices (4 without fluoride and 19 with fluoride) were purchased in different pharmacies in Lima, Peru. The TF and TSF concentrations found in the dentifrices were determined by ion-selective electrode, expressed in ppm F (µg F/g of dentifrice). The TF concentration in the majority of the fluoride toothpastes matched that shown on the label, except for one declared as 1450 ppm F by the manufacturer, whereas only 515.1 ppm F was found. The concentration of TSF found in the fluoride toothpastes ranged from 457.5 to 1134.8 ppm F. All the dentifrices were formulated with silica, but one also presented calcium carbonate. In conclusion, 83% of the children's dentifrices marketed in Lima, Peru, were fluoridated, but only 53% contained a TSF concentration greater than 1000 ppm F, the minimum concentration required to provide an anticaries effect.

Fluoride content in children's dentifrices marketed in Lima, Peru

Abstract The aim of the present study was to determine the concentration of total fluoride (TF) and total soluble fluoride (TSF) in children's dentifrices marketed in the city of Lima, Peru. Three samples of 23 dentifrices (4 without fluoride and 19 with fluoride) were purchased in different pharmacies in Lima, Peru. The TF and TSF concentrations found in the dentifrices were determined by ion-selective electrode, expressed in ppm F (μg F/g of dentifrice). The TF concentration in the majority of the fluoride toothpastes matched that shown on the label, except for one declared as 1450 ppm F by the manufacturer, whereas only 515.1 ppm F was found. The concentration of TSF found in the fluoride toothpastes ranged from 457.5 to 1134.8 ppm F. All the dentifrices were formulated with silica, but one also presented calcium carbonate. In conclusion, 83% of the children's dentifrices marketed in Lima, Peru, were fluoridated, but only 53% contained a TSF concentration greater than 1000 ppm F, the minimum concentration required to provide an anticaries effect.

Salivary fluoride levels after use of high-fluoride dentifrice.

The aim of the study was to evaluate salivary fluoride (F) availability after toothbrushing with a high-F dentifrice. Twelve adult volunteers took part in this crossover and blind study. F concentration in saliva was determined after brushing with a high-F dentifrice (5000 µg F/g) or with a conventional F concentration dentifrice (1100 µg F/g) followed by a 15 mL distilled water rinse. Samples of nonstimulated saliva were collected on the following times: before (baseline), and immediately after spit (time = 0) and after 1, 2, 3, 4, 5, 10, 15, 20, 30, 45, 60, 90, and 120 min. F analysis was performed with a fluoride-sensitive electrode and the area under curve of F salivary concentration × time (µg F/mL × min(-1)) was calculated. At baseline, no significant difference was found among dentifrices (P > 0.05). After brushing, both dentifrices caused an elevated fluoride level in saliva; however salivary F concentration was significantly higher at all times, when high-F dentifrice was used (P < 0.01). Even after 120 min, salivary F concentration was still higher than the baseline values for both dentifrices (P < 0.001). High-F dentifrice enhanced the bioavailability of salivary F, being an option for caries management in patients with high caries risk.

Laboratory and human studies to estimate anticaries efficacy of fluoride toothpastes.

Much more than mechanical biofilm removal, toothbrushing with fluoride toothpastes is an effective way of increasing the availability of fluoride in the oral cavity to reduce demineralization and enhance remineralization of enamel and dentine. These effects of fluoride toothpastes have been estimated by a wide range of laboratory and human studies, which have helped to develop anticaries effective formulations and understand their mechanism of action. These studies have focused on the availability of fluoride in the toothpaste formulations, its bioavailability in saliva and remnants of disturbed biofilm, its reaction with the dental substrate to form loosely bound reservoirs as well as the ultimate reduction of mineral loss and increase in mineral and fluoride content of caries lesions. The specifics of these modes of action and their application in in vitro, in situ and in vivo preclinical tests is presented and discussed.

Physical exercise ameliorates the toxic effect of fluoride on the insulin-glucose system.

Daily intake of water with fluoride concentrations >1.5 mg/l produces insulin resistance (IR). On the other hand, physical activity increases insulin sensitivity in the muscle. Therefore, the aim of this study was to evaluate the effect of physical activity on IR in rats treated with sodium fluoride (NaF) in drinking water. Sprague-Dawley rats were divided into three groups (n=10/group): Control (drinking water without NaF), NaF (drinking water with NaF 15 mg/l for 30 days), and Exercise (daily running on a treadmill for 60 min at 2.25 m/min and drinking water with NaF 15 mg/l for 30 days). IR was evaluated with the homeostasis model assessment-IR (HOMA-IR) index using fasting plasma levels of glucose and insulin. IR increased in rats treated with 15 mg/l NaF in drinking water. A decrease in IR was observed in rats that performed physical activity and drank water with 15 mg/l NaF; the Exercise group also showed an increase in the amounts of bone fluoride. The variation in the HOMA-IR values could be the consequence of variation in the sensitivity of tissues to insulin or decrease in plasma fluoride levels due to bone fluoride intake. These findings indicate that the performance of daily physical activity could reduce the negative effects of the chronic ingestion of NaF on glucose homeostasis.

Available fluoride in toothpastes used by Brazilian children.

Toothpastes should have a minimum concentration of 1000 ppm of fluoride (F) to control caries and also the active F agent must be chemically free (soluble) in the formulation. Thus, the aim of this study was to evaluate the concentration of soluble F in dentifrices used by 206 Brazilian children. The concentrations of total fluoride (TF), total soluble fluoride (TSF) and fluoride ion were determined. From these analyses, the concentrations of F as sodium monofluorophosphate (MFP) and % of insoluble F were calculated. F was analyzed with an ion specific electrode in duplicates. The majority of dentifrices used (96%) contained F and in 84% of them, TF concentration was according to that declared by the manufacturers. In the F-toothpastes, 78% showed TSF concentration ≥ 1000 ppm, varying from 422.3 to 1432.3 ppm F (mean ± SD of 1017.6 ± 239.4). These findings suggest that most dentifrices used by Brazilian children present available fluoride concentration for caries control.

Low-fluoride toothpaste and deciduous enamel demineralization under biofilm accumulation and sucrose exposure.

Because low-fluoride toothpaste (500 p.p.m. F) has not clearly been shown to be effective for controlling caries in caries-active children, this experimental in situ study was conducted to evaluate whether its effect, when compared with a conventional toothpaste (1,000-1,500 p.p.m. F), would depend on the cariogenic challenge. During four phases of 14 d each, 14 volunteers used 500 or 1,100 p.p.m. F toothpaste and wore palatal appliances containing deciduous enamel slabs, on which biofilm was accumulated and exposed to 20% sucrose solution at frequencies increasing from two to eight times per day. The F concentration was determined in the biofilm formed, and enamel demineralization was assessed by surface hardness loss (% SHL) and integrated area of hardness x lesion depth (DeltaS). The F uptake by enamel was also determined. Fluoride in biofilm fluid and solids was statistically higher when conventional F toothpaste was used. The toothpastes did not differ statistically in terms of % SHL, DeltaS, and F in enamel, but only the conventional F toothpaste significantly reduced caries-lesion progression according to the frequency of sucrose exposure. The findings suggest that the high-F availability in biofilm, resulting from the use of conventional toothpaste compared with low-F toothpaste, may be important for reducing caries-lesion progression in conjunction with a high frequency of sucrose exposure.

Chitosan effect on dental enamel de-remineralization: an in vitro evaluation.

OBJECTIVES: The aim of this work was to evaluate the in vitro effect of chitosan (concentration and time of action) treatment on enamel de-remineralization behavior upon a pH cycling assay. METHODS: Different group of human tooth samples were exposed to de-remineralizing solutions of controlled pH using a random experimental design. Microhardness and phosphorus chemical analysis were employed to evaluate the loss of phosphorus from the samples. Optical coherence tomography (OCT) images were obtained for selected specimens in order to evaluate the degree of penetration of chitosan into enamel. RESULTS: Vickers microhardness results were higher for samples treated with chitosan for concentration between 2.5mg/mL and 5.0mg/mL and time of action between 60s and 90 s. A maximum inhibition of mineral loss of 81% was obtained. Chemical analysis indicated lower net pohosphorus loss (net P loss) for samples treated with chitosan. Best results were obtained in the same conditions found out with microhardness measurements. Chitosan had little effect on the remineralization process. OCT results indicated a correlation of chitosan penetration with chitosan concentration. For chitosan concentrations of 2.5 g/mL and 5.0 g/mL the penetration was up to the dentin-enamel junction. CONCLUSIONS: Chitosan interferes with the process of demineralization of the tooth enamel inhibiting the release of phosphorus in this laboratory study. Demineralization is influenced by the concentration and exposure time of the biopolymer to the enamel. Microhardness measurements may be used as an indication of mineral loss from tooth enamel. Additionally, OCT images support the idea that chitosan may act as a barrier against acid penetration, contributing to its demineralization inhibition.

Effects of regular and low-fluoride dentifrices on plaque fluoride.

Previous studies have indicated that the use of low-fluoride dentifrices could lead to proportionally higher plaque fluoride levels when compared with conventional dentifrices. This double-blind, randomized, crossover study determined the effects of placebo, low-fluoride, and conventional dentifrices on plaque fluoride concentrations ([F]) in children living in communities with 0.04, 0.72, and 3.36 ppm F in the drinking water. Children used the toothpastes twice daily, for 1 wk. Samples were collected 1 and 12 hrs after the last use of dentifrices and were analyzed for fluoride and calcium. Similar increases were found 1 hr after the children brushed with low-fluoride (ca. 1.9 mmol F/kg) and conventional (ca. 2.4 mmol F/kg) dentifrices in the 0.04- and 0.72-ppm-F communities. Despite the fact that the increases were less pronounced in the 3.36-ppm-F community, our results indicate that the use of a low-fluoride dentifrice promotes a proportionally higher increase in plaque [F] when compared with that achieved with a conventional dentifrice, based on dose-response considerations.

Fluorosis in rats exposed to oscillating chronic fluoride doses.

Considering that blood fluoride concentration varies according to fluoride exposure and that dental fluorosis is related to the amount of enamel formed under a given fluoride dose, the present study investigated whether the fluorosis produced by an oscillating chronic fluoride dose would be similar to that caused by exposure to a constant dose, representing the mean of the oscillation during a given time. Rats received during 78 days water with fluoride concentrations of 0, 12.5, 25 or 37.5 microg F/mL, or oscillating concentrations of 12.5 and 37.5 microg F/mL every 72 h (mean exposure=25 microg F/mL). The concentrations of fluoride in the plasma, femur and incisors of the rats were determined at the end of the experimental period. Also, the enamel dental fluorosis index was determined in the incisors using a quantitative method developed by our research group named Dental Fluorosis by Image Analysis (DFIA). Fluoride concentrations in plasma, femur and teeth, and DFIA increased linearly for constant fluoride concentrations in water (p<0.0001, r values=0.87-0.98). The results of the oscillating group and the groups receiving 25 microg F/mL did not differ significantly (p>0.05). The findings of this study suggest that in animals chronically exposed to symmetrically oscillating fluoride doses, the resulting dental fluorosis reflects the metabolic effect of the mean of the oscillating doses.

Relationships between fluoride intake, urinary fluoride excretion and fluoride retention in children and adults: an analysis of available data.

The aim of this study was to examine the relationship between total daily fluoride intake (TDFI), daily urinary fluoride excretion (DUFE) and fractional fluoride retention (FFR) using available data, in order to clarify the ability of DUFE to predict TDFI and, therefore, the risk of fluorosis development. Examination of published reports of simultaneous measurement of TDFI and DUFE, together with data from two unpublished Chilean studies, yielded data for 212 children aged less than 7 years and for 283 adults aged 18-75 years, providing a total of 212 and 269 data points, respectively. The relationship between DUFE and TDFI was studied for children and adults, separately. Daily fluoride retention (DFR) was estimated as a function of TDFI in children and adults assuming an average 90% fluoride absorption, and the numerical relationships between the estimated FFR and the TDFI were explored. Limiting FFR values of 0.55 and 0.36 were found for children and adults, respectively, above a threshold of TDFI of 0.5 and 2 mg, respectively. Neutral fluoride balances were predicted when the TDFI was equal to approximately 0.07 mg F/day for children and 0.8 mg F/day for adults. For children and adults, it is possible to obtain reasonably good estimations of community-based TDFI and DFR, using DUFE data. The advantages and limitations of these relationships, together with the need for future studies, are discussed.

Fluorosis in rats exposed to oscillating chronic fluoride doses

Considering that blood fluoride concentration varies according to fluoride exposure and that dental fluorosis is related to the amount of enamel formed under a given fluoride dose, the present study investigated whether the fluorosis produced by an oscillating chronic fluoride dose would be similar to that caused by exposure to a constant dose, representing the mean of the oscillation during a given time. Rats received during 78 days water with fluoride concentrations of 0, 12.5, 25 or 37.5 µg F/mL, or oscillating concentrations of 12.5 and 37.5 µg F/mL every 72 h (mean exposure=25 µg F/mL). The concentrations of fluoride in the plasma, femur and incisors of the rats were determined at the end of the experimental period. Also, the enamel dental fluorosis index was determined in the incisors using a quantitative method developed by our research group named Dental Fluorosis by Image Analysis (DFIA). Fluoride concentrations in plasma, femur and teeth, and DFIA increased linearly for constant fluoride concentrations in water (p<0.0001, r values=0.87-0.98). The results of the oscillating group and the groups receiving 25 µg F/mL did not differ significantly (p>0.05). The findings of this study suggest that in animals chronically exposed to symmetrically oscillating fluoride doses, the resulting dental fluorosis reflects the metabolic effect of the mean of the oscillating doses.

Considerando que a concentração de fluoreto no sangue varia de acordo com a exposição ao fluoreto, e que a fluorose dental está relacionada com a quantidade de esmalte formado sob determinada dose de fluoreto, este estudo avaliou se a fluorose resultante da exposição a doses oscilantes de fluoreto seria semelhante àquela causada pela exposição a uma dose constante, representativa da média das oscilações durante um determinado tempo. Durante 78 dias, ratos receberam água com concentrações constantes de fluoreto de 0; 12,5; 25 ou 37,5 µg F/mL, ou concentrações oscilantes de 12,5 e 37,5 µg F/mL alternados a cada 72 h (média de exposição = 25 µg F/mL). Concentrações de fluoreto no plasma, fêmur e dentes incisivos dos ratos foram determinadas após o período experimental. O índice de fluorose, observado nos incisivos dos ratos, foi quantificado usando um método de análise de imagem desenvolvido para essa pesquisa, denominado de índice de fluorose por análise de imagem (DFIA, em Inglês). A concentração de fluoreto no plasma, fêmur e incisivo dos ratos, assim como o DFIA, aumentaram de forma linear para as concentrações constantes de fluoreto na água (p<0,0001, r=0,87-0,98). Não houve diferença significativa entre o grupo que recebeu doses oscilantes e o grupo que recebeu 25 µg F/mL (p>0,05). Os resultados sugerem a fluorose dental decorrente de exposição crônica de animais a doses de fluoreto oscilantes e simétricas reflete o efeito metabólico da média da oscilação.

Available fluoride in toothpastes used by Brazilian children

Toothpastes should have a minimum concentration of 1000 ppm of fluoride (F) to control caries and also the active F agent must be chemically free (soluble) in the formulation. Thus, the aim of this study was to evaluate the concentration of soluble F in dentifrices used by 206 Brazilian children. The concentrations of total fluoride (TF), total soluble fluoride (TSF) and fluoride ion were determined. From these analyses, the concentrations of F as sodium monofluorophosphate (MFP) and percent of insoluble F were calculated. F was analyzed with an ion specific electrode in duplicates. The majority of dentifrices used (96 percent) contained F and in 84 percent of them, TF concentration was according to that declared by the manufacturers. In the F-toothpastes, 78 percent showed TSF concentration ≥1000 ppm, varying from 422.3 to 1432.3 ppm F (mean ± SD of 1017.6 ± 239.4). These findings suggest that most dentifrices used by Brazilian children present available fluoride concentration for caries control.

O requerimento mínimo para que um creme dental tenha potencial anticárie é ele ter fluoreto (F) na concentração de 1000 ppm, o qual porém deve estar solúvel na formulação. Assim, este estudo teve como objetivo conhecer a concentração de F solúvel em dentifrícios usados por 206 crianças brasileiras. Foram determinadas as concentrações de flúor total (FT), o qual representa a soma das concentrações de flúor solúvel (iônico e ionizável) mais o insolúvel (ligado ao abrasivo); de flúor solúvel total (FST), representando o iônico mais o ionizável na forma de monofluorfosfato de sódio (MFP) e de flúor solúvel na forma iônica (FI). A partir destas análises foram calculadas as concentrações de MFP e a por cento de F insolúvel (Fins). As análises foram feitas em duplicatas com eletrodo específico. A maioria dos dentifrícios usados (96 por cento) continham fluoreto e em 84 por cento desses a concentração de FT encontrada estava de acordo com a declarada na embalagem. Em 78 por cento dos cremes dentais fluoretados, a concentração de FST encontrada foi igual ou superior a 1000 ppm, variando de 422,3 a 1432,3 ppm F (média ± DP de 1017,6 ± 239,4). Os dados mostram que a maioria dos cremes dentais usados pela amostra de crianças brasileiras possui concentração de F potencialmente ativo para controlar cárie.

Influence of genetic background on fluoride metabolism in mice.

A/J and 129P3/J mouse strains have different susceptibilities to dental fluorosis, due to their genetic backgrounds. This study tested whether these differences are due to variations in water intake and/or F metabolism. A/J (susceptible to dental fluorosis) and 129P3/J mice (resistant) received drinking water containing 0, 10, or 50 ppm F. Weekly F intake, excretion and retention, and terminal plasma and femur F levels were determined. Dental fluorosis was evaluated clinically and by quantitative fluorescence (QF). Data were tested by two-way ANOVA. Although F intakes by the strains were similar, excretion by A/J mice was significantly higher due to greater urinary F excretion, which resulted in lower plasma and femur F levels. Compared with 129P3/J mice given 50 ppm F, significantly higher QF scores were recorded for A/J mice. In conclusion, these strains differ with respect to several features of F metabolism, and amelogenesis in the 129P3/J strain seems to be unaffected by high F exposure.

The fractional urinary fluoride excretion of adults consuming naturally and artificially fluoridated water and the influence of water hardness: a randomized trial.

AIMS: To assess whether there was any significant difference in the average fractional urinary fluoride excretion (FUFE) values among adults consuming (NaF) fluoridated Ca-free water (reference water), naturally fluoridated hard water and an artificially (H2SiF6) fluoridated soft water. DESIGN: Sixty adult females (N=20 for each treatment) participated in this randomized, double-blind trial. The experimental design of this study provided an indirect estimation of the fluoride absorption in different types of water through the assessment of the fractional urinary fluoride excretion of volunteers. RESULTS: Average daily FUFE values (daily amount of fluoride excreted in urine/daily total fluoride intake) were not significantly different between the three treatments (Kruskal-Wallis; p = 0.62). The average 24-hour FUFE value (n=60) was 0.69; 95% C.I. 0.65-0.73. CONCLUSIONS: The results of this study suggest that the absorption of fluoride is not affected by water hardness.

Urinary fluoride output in children following the use of a dual-fluoride varnish formulation

OBJECTIVE: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to DuraphatTM. MATERIAL AND METHODS: The urinary fluoride output was evaluated in seven 5-year-old children after application of the fluoride varnishes, in two different phases. In the first phase (I), children received topical application of the fluoride varnish Duofluorid XII (2.92 percent fluorine, calcium fluoride + 2.71 percent fluorine, sodium fluoride, FGM TM). After 1-month interval (phase II), the same amount (0.2 mL) of the fluoride varnish Duraphat (2.26 percent fluorine, sodium fluoride, ColgateTM) was applied. Before each application all the volunteers brushed their teeth with placebo dentifrice for 7 days. Urinary collections were carried out 24 h prior up to 48 h after the applications. Fluoride intake from the diet was also estimated. Fluoride concentration in diet samples and urine was analyzed with the fluoride ion-specific electrode and a miniature calomel reference electrode coupled to a potentiometer. Data were tested by ANOVA and Tukey's post hoc test (p<0.05). RESULTS: There were significant differences in the urinary fluoride output between phases I and II. The use of Duofluorid XII did not significantly increase the urinary fluoride output, when compared to baseline levels. The application of Duraphat caused a transitory increase in the urinary fluoride output, returning to baseline levels 48 h after its use. CONCLUSIONS: The tested varnish formulation, which has been shown to be effective in in vitro studies, also can be considered safe.

Mechanism of fluoride dentifrice effect on enamel demineralization.

Although the anticaries effect of fluoride (F) dentifrices is clearly established, the relative importance of F taken up by dental plaque not removed by brushing and of F products (CaF(2)-like) formed on totally cleaned enamel for the subsequent inhibition of demineralization is not known. Both effects were evaluated using conventional (1,100 microg F/g) and low-F concentration (500 microg F/g) dentifrices in a randomized, crossover, double-blind in situ study. Enamel blocks not treated or pretreated with the dentifrices to form CaF(2)-like deposits were mounted in palatal appliances in contact with a Streptococcus mutans test plaque. Volunteers brushed with non-F (negative control), low-F or conventional dentifrices and inserted the appliance in the mouth. F concentration in the fluid and solid phases of the test plaque was determined after 30 min, and a rinse with 20% sucrose solution was performed. After additional 45 min, plaque was collected and the loss of surface hardness at different test-plaque depths was measured. CaF(2)-like deposition on enamel and F taken up by plaque due to the use of F dentifrices were able to significantly increase F concentration in the fluid phase of the test plaque, but only the latter significantly reduced the loss of hardness because of the 20-30 times higher F concentration. Also, significant differences between the low-F and conventional dentifrices were observed for F on enamel, in plaque and on the subsequent loss of hardness. The results suggest that uptake of F by dental plaque not removed by brushing may be the main cause of the anticaries effect of F dentifrices.

Effect of APF gel application time on enamel demineralization and fluoride uptake in situ.

This in situ crossover and blind study was conducted to investigate the effect of professional acidulated phosphate fluoride (APF) gel application time on the subsequent inhibition of enamel demineralization. During 3 phases of 28 days each, 15 volunteers wore palatal appliances containing 4 enamel blocks, which were subjected to 3 treatment groups: not treated (control) and pre-treated with APF gel for 1 or 4 min. Dental plaque was allowed to accumulate on the blocks and the appliances were immersed in 10% sucrose solution 3 times a day simulating a cariogenic challenge. After each phase, the blocks were removed to evaluate enamel demineralization and concentration of fluoride (F) remaining after the cariogenic challenge. F formed on enamel was determined in additional enamel blocks subjected only to APF gel application. APF gel was efficient in reducing enamel demineralization (p<0.05), irrespective of the application time (p>0.05). Also, the concentration of the F formed and retained on enamel was significantly higher after APF gel application (p<0.05), but the effect of time of application was not statistically significant (p>0.05). The results suggest that APF application for either 1 or 4 min is equally efficient to increase F concentration in enamel and reduce enamel demineralization.

Urinary fluoride output in children following the use of a dual-fluoride varnish formulation.

OBJECTIVE: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to Duraphat. MATERIAL AND METHODS: The urinary fluoride output was evaluated in seven 5-year-old children after application of the fluoride varnishes, in two different phases. In the first phase (I), children received topical application of the fluoride varnish Duofluorid XII (2.92% fluorine, calcium fluoride + 2.71% fluorine, sodium fluoride, FGM). After 1-month interval (phase II), the same amount (0.2 mL) of the fluoride varnish Duraphat (2.26% fluorine, sodium fluoride, Colgate) was applied. Before each application all the volunteers brushed their teeth with placebo dentifrice for 7 days. Urinary collections were carried out 24 h prior up to 48 h after the applications. Fluoride intake from the diet was also estimated. Fluoride concentration in diet samples and urine was analyzed with the fluoride ion-specific electrode and a miniature calomel reference electrode coupled to a potentiometer. Data were tested by ANOVA and Tukey's post hoc test (p<0.05). RESULTS: There were significant differences in the urinary fluoride output between phases I and II. The use of Duofluorid XII did not significantly increase the urinary fluoride output, when compared to baseline levels. The application of Duraphat caused a transitory increase in the urinary fluoride output, returning to baseline levels 48 h after its use. CONCLUSIONS: The tested varnish formulation, which has been shown to be effective in in vitro studies, also can be considered safe.

Effect of APF gel application time on enamel demineralization and fluoride uptake in situ

This in situ crossover and blind study was conducted to investigate the effect of professional acidulated phosphate fluoride (APF) gel application time on the subsequent inhibition of enamel demineralization. During 3 phases of 28 days each, 15 volunteers wore palatal appliances containing 4 enamel blocks, which were subjected to 3 treatment groups: not treated (control) and pre-treated with APF gel for 1 or 4 min. Dental plaque was allowed to accumulate on the blocks and the appliances were immersed in 10 percent sucrose solution 3 times a day simulating a cariogenic challenge. After each phase, the blocks were removed to evaluate enamel demineralization and concentration of fluoride (F) remaining after the cariogenic challenge. F formed on enamel was determined in additional enamel blocks subjected only to APF gel application. APF gel was efficient in reducing enamel demineralization (p<0.05), irrespective of the application time (p>0.05). Also, the concentration of the F formed and retained on enamel was significantly higher after APF gel application (p<0.05), but the effect of time of application was not statistically significant (p>0.05). The results suggest that APF application for either 1 or 4 min is equally efficient to increase F concentration in enamel and reduce enamel demineralization.

Considerando que o efeito do tempo da aplicação profissional de flúor fosfato acidulado (FFA) na subseqüente inibição da desmineralização do esmalte dental não está claramente estabelecido, este foi avaliado em um estudo in situ, cruzado e cego. Em 3 fases de 28 dias cada uma, 15 voluntários utilizaram um dispositivo palatino contendo 4 blocos de esmalte, que foram submetidos a 3 grupos/tratamentos: não tratado (controle) e pré-tratado com FFA gel por 1 ou 4 min. Placa dental foi acumulada sobre os blocos e 3 vezes ao dia os dispositivos foram imersos em uma solução de sacarose a 10 por cento simulando um desafio cariogênico. Após cada fase, os blocos foram removidos para avaliação da desmineralização do esmalte e concentração de fluoreto (F) remanescente após o desafio cariogênico. O F formado no esmalte foi determinado em blocos adicionais submetidos apenas à aplicação de FFA gel. O tratamento com FFA gel reduziu a desmineralização do esmalte (p<0,05), independentemente do tempo de aplicação (p>0,05). Adicionalmente, a concentração de F formado e retido no esmalte foi significantemente maior após a aplicação do FFA gel (p<0,05), mas o efeito do tempo de aplicação não foi estatisticamente significante (p>0,05). Os resultados sugerem que não há diferença entre os tempos 1 ou 4 min de aplicação de FFA gel em termos de aumento da concentração de F no esmalte e redução de sua desmineralização frente a um desafio cariogênico.