RESUMO
The aim of this study was to validate the use of fingernail fluoride concentrations at ages 2-7 years as predictors of the risk for developing dental fluorosis in the permanent dentition. Fifty-six children of both genders (10-15 years of age) had their incisors and premolars examined for dental fluorosis using the Thylstrup-Fejerskov index. Fingernail fluoride concentrations were obtained from previous studies when children were 2-7 years of age. Data were analyzed by unpaired t test, ANOVA, and Fisher's exact test when the fingernail fluoride concentrations were dichotomized (≤ 2 or >2 µg/g). Children with dental fluorosis had significantly higher fingernail fluoride concentrations than those without the condition, and the concentrations tended to increase with the severity of fluorosis (r(2) = 0.47, p < 0.0001). Using a fingernail fluoride concentration of 2 µg/g at ages 2-7 years as a threshold, this biomarker had high sensitivity (0.84) and moderate specificity (0.53) as a predictor for dental fluorosis. The high positive predictive value indicates that fingernail fluoride concentrations should be useful in public health research, since it has the potential to identify around 80% of children at risk of developing dental fluorosis.
Assuntos
Cariostáticos/análise , Fluoretos/análise , Fluorose Dentária/etiologia , Unhas/química , Adolescente , Fatores Etários , Dente Pré-Molar/patologia , Biomarcadores/análise , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Feminino , Fluoretação , Fluorose Dentária/classificação , Seguimentos , Previsões , Humanos , Incisivo/patologia , Masculino , Valor Preditivo dos Testes , Fatores de Risco , Sensibilidade e Especificidade , Abastecimento de Água/análiseRESUMO
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.
Assuntos
Cariostáticos/administração & dosagem , Placa Dentária/química , Dentifrícios/administração & dosagem , Fluoretos/administração & dosagem , Cálcio/análise , Cariostáticos/análise , Cariostáticos/farmacocinética , Criança , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Fluoretos/análise , Fluoretos/farmacocinética , Humanos , Placebos , Espectrofotometria Atômica , Fatores de Tempo , Escovação Dentária , Abastecimento de Água/análiseRESUMO
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.
Assuntos
Cariostáticos/farmacocinética , Fluoretos/farmacocinética , Fluorose Dentária/genética , Predisposição Genética para Doença/genética , Absorção , Amelogênese/efeitos dos fármacos , Animais , Peso Corporal , Cariostáticos/administração & dosagem , Cariostáticos/análise , Ingestão de Líquidos , Ingestão de Alimentos , Fezes/química , Fêmur/química , Fluorescência , Fluoretos/administração & dosagem , Fluoretos/análise , Fluoretos/sangue , Fluoretos/urina , Fluorose Dentária/metabolismo , Fluorose Dentária/patologia , Incisivo/patologia , Masculino , Camundongos , Camundongos Endogâmicos A , Camundongos EndogâmicosRESUMO
It has been suggested that fluoride retention in plaque is limited by available binding sites. We determined the effects of fluoridated or placebo dentifrices on plaque and salivary fluoride concentrations [F]s in communities with different water fluoride concentrations (0.04, 0.85, 3.5 ppm). After one week of dentifrice use, samples were collected 1.0 and 12 hrs after the last use of dentifrices. After the use of fluoridated dentifrice, plaque fluoride concentrations were higher at both times, except at 12 hrs in the 3.5-ppm community. Plaque concentrations at 1.0 hr after the use of fluoridated dentifrice increased almost constantly (6.5 mmol/kg), but then decreased approximately 50% at 12 hrs in each community. Unlike previous studies, the present findings suggest that the use of fluoridated dentifrice is likely to increase plaque fluoride concentrations significantly for up to 12 hrs in areas where the water contains fluoride close to 1.0 ppm. As previously reported, plaque fluoride concentrations were directly related to calcium concentrations.
Assuntos
Cariostáticos/farmacocinética , Placa Dentária/metabolismo , Dentifrícios/farmacocinética , Fluoretação , Fluoretos Tópicos/farmacocinética , Análise de Variância , Cálcio/metabolismo , Criança , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Humanos , Saliva/metabolismo , Fatores de Tempo , Resultado do TratamentoRESUMO
The results of a recent study by Whitford et al. [Caries Res 2002;36:256-265] with subjects whose drinking water was fluoridated led to two major conclusions: (1) Compared to the use of a placebo dentifrice, plaque fluoride concentrations ([F]) throughout much of the day are not significantly increased by the use of an F dentifrice but (2) they are positively related to plaque [Ca] (p = 0.0001). The present double-blind, double-crossover study with 16 subjects used the same protocol and was done to: (1) determine the effects of the use of an F dentifrice on salivary and plaque [F] in a community without water fluoridation and (2) further examine the relationship between plaque [Ca] and [F]. Following the use of an F dentifrice or placebo for one week, whole saliva and plaque were collected 1.0 and 12 h after the last use of the products. The study was repeated to include rinsing with a 20 mmol/l CaCl(2) solution immediately before the use of the dentifrices. The CaCl(2) rinse had only minor effects on salivary [Ca] and [F] and none on the plaque concentrations. Unlike the results found in the fluoridated community, all salivary and plaque [F] associated with the use of the F dentifrice were significantly higher than those associated with the use of the placebo. The results suggest that the cariostatic effectiveness of an F dentifrice should be greater in areas without water fluoridation. As noted previously, plaque [F] were positively related to plaque [Ca] (p = 0.0001).
Assuntos
Cálcio/análise , Cariostáticos/análise , Placa Dentária/química , Dentifrícios/uso terapêutico , Fluoretos/análise , Adolescente , Brasil , Cálcio/uso terapêutico , Cloreto de Cálcio/uso terapêutico , Cariostáticos/uso terapêutico , Criança , Estudos Cross-Over , Método Duplo-Cego , Fluoretação , Fluoretos/uso terapêutico , Humanos , Antissépticos Bucais/uso terapêutico , Placebos , Saliva/química , Saliva/metabolismo , Taxa Secretória/fisiologia , Espectrofotometria Atômica , Fatores de TempoRESUMO
This work was based on the hypothesis that fingernail clippings can be used as a biomarker for the subchronic exposure to fluoride. The results provide data on factors that may affect the concentration of fluoride in fingernail clippings as determined with the electrode following HMDS-facilitated diffusion. The following variables had only minor or no effects on the concentrations: (1) the surface area of the clippings (intact, minced or filed into powder) that were placed into the diffusion dishes; (2) soaking in deionized water for up to 6 h; (3) soaking in fluoridated water (1.0 ppm) for 2 h, and (4) removal of the organic material of nails by dry ashing. Fingernail fluoride concentrations were approximately 50% higher than those in toenails. A 1-month period of increased fluoride intake by one of the authors resulted in significant increases in fingernail fluoride concentrations after a lag time of approximately 3.5 months. The fluoride concentrations in fingernail clippings obtained from three groups of Brazilian children were directly related to the concentrations in the drinking water (0.1, 1.6 or 2.3 ppm). The results indicate that: (1) HMDS-facilitated diffusion completely separates fluoride from intact nail clippings, so the need for ashing or other preparative methods is obviated; (2) fingernail fluoride is derived mainly from the systemic circulation, and (3) fluoride intake is reflected by the concentrations in fingernails.