Flávia Mauad Levy

Programa de agentes comunitários de saúde: a percepção de usuários e trabalhadores da saúde

Two basic premises of Brazils Community Health Agents Program (PACS) are to value the family and community to which the program belongs and to encourage their participation in health promotion and disease prevention. This study focused on the work developed by PACS in Bauru, São Paulo State, as perceived by the community health agents and the families served by them. As the studys point of departure, 22 community health agents and 22 representatives of families were interviewed, randomly selected according to residential micro-areas. Two focus groups were formed according to the PACS to which the community agents and families belonged. Qualitative analysis of the answers demonstrated agreement between the perceptions by community health agents and the community in the two focus groups. However, the two focus groups differed from each other. Distinct realities were observed in the two communities, thereby orienting new program actions and handling of local difficulties.

Effect of a single application of TiF4 and NaF varnishes and solutions on dentin erosion in vitro

OBJECTIVES This in vitro study aimed to analyse the effect of a single application of TiF(4) and NaF varnishes and solutions to protect against dentin erosion. METHODS Bovine root dentin samples were pre-treated with NaF-Duraphat varnish (2.26%F, pH 4.5), NaF/CaF(2)-Duofluorid varnish (5.63%F, pH 8.0), NaF-experimental varnish (2.45%F, pH 4.5), TiF(4)-experimental varnish (2.45%F, pH 1.2), NaF solution (2.26%F, pH 4.5), TiF(4) solution (2.45%F, pH 1.2) and placebo varnish (pH 5.0, no-F varnish control). Controls remained untreated. Ten samples in each group were then subjected to an erosive demineralisation (Sprite Zero, 4x 90s/day) and remineralisation (artificial saliva, between the erosive cycles) cycling for 5 days. Dentin loss was measured profilometrically after pre-treatment and after 1, 3 and 5 days of de-remineralisation cycling. The data were statistically analysed by two-way ANOVA and Bonferronis post hoc test (p<0.05). RESULTS After pre-treatment, TiF(4) solution significantly induced surface loss (1.08+/-0.53 microm). Only Duraphat reduced the dentin loss overtime, but it did not significantly differ from placebo varnish (at 3rd and 5th days) and TiF(4) varnish (at 3rd day). CONCLUSIONS Duraphat varnish seems to be the best option to partially reduce dentin erosion. However, the maintenance of the effects of this treatment after successive erosive challenges is limited.

The erosion and abrasion‐inhibiting effect of TiF4 and NaF varnishes and solutions on enamel in vitro

OBJECTIVE. Previous in vitro study has shown that TiF(4) varnish might reduce enamel erosion. No data regarding the effect of this experimental varnish on enamel erosion plus abrasion, however, are available so far. Thus, this in vitro study aimed to analyse the effect of TiF(4) compared with NaF varnishes and solutions, to protect against enamel erosion with or without abrasion. METHODS. Enamel specimens were pre-treated with experimental-TiF(4) (2.45% F), experimental-NaF (2.45% F), NaF-Duraphat (2.26% F), and placebo varnishes; NaF (2.26% F) and TiF(4) (2.45% F) solutions. Controls remained untreated. The erosive challenge was performed using a soft drink (pH 2.6) 4 × 90 s/day (ERO) and the toothbrushing abrasion (ERO+ABR) 2 × 10 s/day, for 5 days. Between the challenges, the specimens were exposed to artificial saliva. Enamel loss was measured profilometrically (μm). RESULTS. Kruskal-Wallis/Dunn tests showed that all fluoridated varnishes (TiF(4) -ERO:0.53 ± 0.20, ERO+ABR:0.65 ± 0.19/NaF-ERO:0.94 ± 0.18, ERO+ABR:1.74 ± 0.37/Duraphat-ERO:1.00 ± 0.37, ERO+ABR:1.72 ± 0.58) were able to significantly reduce enamel loss when compared with placebo varnish (ERO:3.45 ± 0.41/ERO+ABR:3.20 ± 0.66) (P < 0.0001). Placebo varnish, control (ERO:2.68 ± 0.53/ERO+ABR:3.01 ± 0.34), and fluoridated (NaF-ERO:2.84 ± 0.09/ERO+ABR:2.40 ± 0.21/TiF(4) -ERO:3.55 ± 0.59/ERO+ABR:4.10 ± 0.38) solutions did not significantly differ from each other. CONCLUSION. Based on the results, it can be concluded that the TiF(4) varnish seems to be a promising treatment to reduce enamel loss under mild erosive and abrasive conditions in vitro.

Effect of NaF and TiF4 varnish and solution on bovine dentin erosion plus abrasion in vitro

Abstract Objectives. This in vitro study aimed to analyze the effect of TiF4 compared to NaF varnishes and solutions, to protect against dentin erosion associated with abrasion. Materials and methods. Bovine dentin specimens were pre-treated with NaF-Duraphat (2.26% F), NaF/CaF2-Duofluorid (5.63% F), experimental-NaF (2.45% F), experimental-TiF4 (2.45% F) and placebo varnishes; NaF (2.26% F) and TiF4 (2.45% F) solutions. Controls remained untreated. The erosive pH cycling was performed using a soft drink (pH 2.6) 4 × 90 s/day and the toothbrushing-abrasion 2 × 10 s/day, in vitro for 5 days. Between the challenges, the specimens were exposed to artificial saliva. Dentin tissue loss was measured profilometrically (μm). Results. ANOVA/Tukeys test showed that all fluoridated varnishes (Duraphat, 7.5 ± 1.1; Duofluorid, 6.8 ± 1.1; NaF, 7.2 ± 1.9; TiF4, 6.5 ± 1.0) were able to significantly reduce dentin tissue loss (40.7% reduction compared to control) when compared to placebo varnish (11.2 ± 1.3), control (11.8 ± 1.7) and fluoridated (NaF, 9.9 ± 1.8; TiF4, 10.3 ± 2.1) solutions (p < 0.0001), which in turn did not significantly differ from each other. Conclusion. All fluoridated varnishes, but not the solutions, had a similar performance and a good potential to reduce dentin tissue loss under mild erosive and abrasive conditions in vitro. Risk patients for erosion and abrasion, especially those with exposed dentin, should benefit from this clinical preventive measure. Further research has to confirm this promising result in the clinical situation.

Fluoride ingestion from food items and dentifrice in 2–6‐year‐old Brazilian children living in a fluoridated area using a semiquantitative food frequency questionnaire

OBJECTIVES The aim of this study was to evaluate the fluoride intake of 2-6-year-old Brazilian children using a semiquantitative food frequency questionnaire (FFQ) which also estimated fluoride intake from dentifrice. METHODS The FFQ was previously validated through application to 78 2-6-year-old Brazilian children and then administered to 379 children residing in an optimally fluoridated community in Brazil (Bauru, State of São Paulo). The FFQ was applied to the parents and used to estimate the food intake of the children. The constituents of the diet were divided into solids, water and other beverages. The fluoride content of the diet items was analyzed with the fluoride electrode. The questionnaire also estimated fluoride intake from dentifrice. RESULTS The average (+/-SD) fluoride intake from solids, water, other beverages and dentifrice was 0.008 +/- 0.005; 0.011 +/- 0.004; 0.009 +/- 0.014 and 0.036 +/- 0.028 mg F/kg body weight/day, respectively, totalizing 0.064 +/- 0.035 mg F/kg body weight/day. The dentifrice and the diet contributed with 56.3% and 43.7% of the daily fluoride intake, respectively. Among the children evaluated, 31.2% are estimated to have risk to develop dental fluorosis (intake>0.07 mg F/kg body weight/day). CONCLUSIONS The dentifrice was the main source of fluoride intake by the children evaluated. However, the fluoride concentration in food items also significantly contributed to the daily ingestion by 2-6-year-old children. The questionnaire used seems to be a promising alternative to duplicate diet to estimate the fluoride intake at this age range and may have potential to be used in broad epidemiological surveys.

Absence of DNA damage in multiple organs (blood, liver, kidney, thyroid gland and urinary bladder) after acute fluoride exposure in rats

Fluoride has been widely used in dentistry as a caries prophylactic agent. However, there has been some speculation that excess fluoride could cause an impact on genome integrity. In the current study, the potential DNA damage associated with exposure to fluoride was assessed in cells of blood, liver, kidney, thyroid gland and urinary bladder by the single cell gel (comet) assay. Male Wistar rats aging 75 days were distributed into seven groups: Groups 1 (control), 2, 3, 4, 5, 6 and 7 received 0 (deionized water), 10, 20, 40, 60, 80 and 100 mgF/Kg body weight from sodium fluoride (NaF), respectively, by gastrogavage. These groups were killed at 2 h after the administration of the fluoride doses. The level of DNA strand breaks did not increase in all organs evaluated and at all doses of NaF tested, as depicted by the mean tail moment. Taken together, our results suggest that oral exposure to NaF did not result in systemic genotoxic effect in multiple organs related to fluoride toxicity. Since DNA damage is an important step in events leading to carcinogenesis, this study represents a relevant contribution to the correct evaluation of the potential health risk associated with chemical exposure.Fluoride intake in low concentrations during tooth development results in the formation of dental enamel that is more resistant to caries. It has been established that a concentration of 0.7 mg/L fluoride reduces caries by 40–49% in primary teeth and 50–59% in permanent teeth, with no clinical appearance of adverse effects.1 Furthermore, some authors have supported the notion that fluoride significantly augments bone cell proliferation either on osteoprogenitor cells or through an indirect mechanism mediated by a co-factor.2–4 However, some human populations are exposed to high doses of fluoride, mainly in developing countries. Herein, studies focusing on possible genotoxic effect of excess fluoride are contradictory and inconclusive.5 According to some authors, fluoride does not induce DNA damage.6–8 However, some authors have observed the genotoxic potential of fluoride in Drosophila melanogaster, rats and human cells.9–11 Information regarding unfavorable reactions among chemicals and living systems proceeds from retrospective studies in man and current knowledge about chemical tissue interactions has been gained through bioassays in vivo and in vitro. Taking into account the tests available in general field, genotoxicity assays are of special concern since genotoxicity has gained widespread acceptance as an important and useful indicator of carcinogenicity.12 This is because these assays are able to measure an initiating *Correspondence: Marilla Afonso Rabelo Buzalaf, Department of Biological Sciences, Bauru Dental School, University of São Paulo, Alameda Octávio Pinheiro Brisolla 9-75, 17012-901, Bauru, SP, Brazil. Tel.: 55-14-32358346; Fax: 55-14-32271486; E-mail: mbuzalaf@fob.usp.br

Total fluoride intake and excretion in children up to 4 years of age living in fluoridated and non-fluoridated areas.

Fractional fluoride retention is important during the early years of life when considering the risk of development of dental fluorosis. This study aimed to measure fractional fluoride retention in young children. The objectives were to investigate the relationships between fractional fluoride retention and total daily fluoride intake, age, and body mass index (BMI). Twenty-nine healthy children, up to 4 yr of age, participated; 14 lived in a fluoridated area (0.64 μg ml(-1) of fluoride in drinking water) and 15 lived in a non-fluoridated area (0.04 μg ml(-1) of fluoride in drinking water). The total daily fluoride intake of each child was calculated from the daily dietary fluoride intake and toothpaste ingestion (if fluoride toothpaste was used). Total daily fluoride excretion was measured by collecting voided urine and faeces over a 24-h period, and fractional fluoride retention was calculated by dividing the amount of fluoride retained in the body (total daily fluoride intake minus total daily fluoride excretion) by the total daily fluoride intake. Nine children were excluded from data analysis because of suspected invalid samples. Mean (range) fractional fluoride retention for the remaining 20 children was 0.61 (0.06-0.98). There were no statistically significant correlations between fractional fluoride retention and either age or BMI. However, fractional fluoride retention was correlated with total daily fluoride intake: fractional fluoride retention = 1 - exp (-C × total daily fluoride intake), where C = 28.75 (95% CI = 19.75-37.75). The wide variation in fluoride retention in young children could have important implications when recommendations for fluoride use are being considered.

Inhibition of tooth erosion by milk containing different fluoride concentrations: An in vitro study

OBJECTIVES This in vitro study assessed the effect of milk containing different fluoride concentrations on tooth erosion. METHODS Bovine enamel and root dentine specimens were treated with: (1) bovine whole milk with 0ppm F; (2) 2.5ppm F; (3) 5ppm F; (4) 10ppm F (all after erosion); (5) whole milk with 0ppm F (before erosion); (6) NaF (0.05% F, positive control, after erosion) or (7) 0.9% NaCl (negative control, after erosion). The specimens were submitted to pH cycles (4× 90s in soft drink) and treatments for 5 days. The specimens were immersed in the treatment solutions for 1min (only at the first cycle each day) with further exposition to 1:1 milk:saliva slurry for 10min. The tooth loss was measured using a contact profilometer and statistically analysed (p<0.05). RESULTS Rinsing with milk before erosive challenge significantly reduced tooth loss compared to negative control (67% and 24% reduction in dentine and enamel loss, respectively) and to milk after erosive challenge, only for dentine. The addition of fluoride to milk also reduced tooth loss compared to negative control, but with no significant differences among fluoride concentrations for enamel and dentine (μm), respectively: 0ppm (3.63±0.04 and 2.51±0.53), 2.5ppm F (2.86±0.42 and 1.96±0.47), 5ppm F (2.81±0.27 and 1.77±0.44), 10ppm F (2.03±0.49 and 1.68±0.59). There was a negative and significant correlation between [F] and the tooth loss. CONCLUSIONS Daily rinse with milk containing F is able to reduce both enamel and dentine erosion in vitro. CLINICAL SIGNIFICANCE Since the prevalence of dental erosion is steadily increasing, rinse with milk or its derivate might be an important strategy to reduce the progression of tooth erosion.

The effect of fluoride on the structure, function, and proteome of a renal epithelial cell monolayer

High concentrations of fluoride in the body may cause toxic effects. Here, we investigated the effects of fluoride on the structure, function, and proteome of a cortical collecting duct epithelium in vitro. Kidney tubule cells (M‐1) were chosen because the concentration of fluoride in the kidney is 4–5‐fold higher than that in plasma. Mouse M‐1 cell monolayers were incubated in fluoride‐containing media, and the amiloride‐sensitive short‐circuit current and transepithelial resistance were measured. The Youngs modulus of the epithelium was determined using atomic force microscopy, and the effect of fluoride on epithelial structure was assessed using scanning and transmission electron microscopy, and immunofluorescence. Differences in the expression of membrane proteins were evaluated using proteomics and bioinformatics. Fluoride exposure reduced both transepithelial Na+ transport and resistance. The IC50 for fluoride was ∼300 µM for both effects, and the half‐times for the decays of ion transport and resistance were 8.4 h and 3.6 days, respectively. Fluoride treatment did not affect the sensitivity of Na+ transport to amiloride. The Youngs modulus of the epithelium was also unaffected by fluoride; however, the functional effects of fluoride were accompanied by marked structural effects. Proteomic analysis revealed changes in expression of a number of proteins, and particularly mitochondrial proteins. Treatment with fluoride had profound effects on the structure, function and proteome of a model cortical collecting duct epithelium. Significantly, however, these effects were produced only at concentrations considerably higher than those likely to be encountered in vivo.

Frequency of intake and amount of fluoride in milk for remineralisation of artificial caries on enamel and dentine: Ex vivo/in situ study

OBJECTIVES This study analysed the effect of frequency of intake and amount of fluoride in milk on the remineralisation of artificial enamel and dentine caries lesions ex vivo/in situ. MATERIALS AND METHODS Pre-demineralised bovine enamel and dentine slabs were randomly allocated into 5 groups and fixed in removable appliances used by subjects for 7days in each phase. Each treatment comprised milk containing 2.5ppm fluoride daily (T1), or every other day (T2), 5.0ppm F daily (T3), or every other day (T4) or no treatment (T5). RESULTS Enamel alterations were quantified by surface hardness recovery (%SHR) and transversal microradiography (TMR), and in dentine by TMR only. Data were analysed by ANOVA and Tukeys test (p<0.05). For enamel, the highest %SHR was found for T1 and T3 compared to control, without significant differences between them. All groups showed positive values of ΔΔZ - T1 (247.3±198.5); T2 (110.9±303.2); T3 (226.0±299.2); T5 (5.0±288.0), except T4 (-274.5±407.3). For dentine, the only group that presented remineralisation was T2 (350.0±657.5). CONCLUSIONS Fluoridated milk daily seems to have higher remineralising effect on enamel than its use every other day. Dentine, does not seem to benefit from daily use of fluoridated milk.