Fluoride in drinking groundwater and prevalence of fluorosis in children and adolescents: A systematic review / Fluoruro en el agua subterránea potable y prevalencia de fluorosis en niños y adolescentes: Una revisión sistemática

ABSTRACT Fluorosis is a worldwide public health problem. One of the factors related to it is the type of water consumed, such as groundwater. High fluoride concentration in groundwater may be explained by contamination from local industries. Since fluoride and arsenic are the main pollutants of groundwater, some studies correlate groundwater consumption with high prevalence of fluorosis Aim The aim of this study was to conduct a systematic review to determine whether children's risk of fluorosis is related to drinking groundwater Materials and Method The protocol for this systematic review was registered at the National Institute of Health Research Database (CRD42021227298). A comprehensive search was conducted to identify potentially relevant studies by exploring a range of electronic databases (Medline via PubMed, Scopus, Cochrane Library, Science Direct, Web of Science Core Collection, Medline via Ovid, Lilacs, Embase, and grey literature) Results A total 2189 articles were found. After reading titles and abstracts, 63 were selected for screening, and the final data was extracted from 15 articles Conclusion A relationship was identified between drinking fluoridated water from wells and the prevalence of fluorosis in individuals up to 18 years old. This is the first study to assess the issue systematically worldwide.

RESUMEN La fluorosis es un problema de salud pública a nivel mundial y el tipo de agua consumida es uno de los factores relacionados con ella, como el consumo de aguas subterráneas. La alta concentración de fluoruro en estas aguas puede justificarse por la contaminación por industrias locales y las características del suelo, donde algunos estudios correlacionan el consumo de aguas subterráneas con una alta prevalencia de fluorosis, ya que el fluoruro, junto con el arsénico, se consideran los principales contaminantes de estas aguas Objetivo El objetivo es realizar una revisión sistemática que relacione el riesgo de fluorosis en niños expuestos al consumo de agua procedente de pozos Materiales y Método El protocolo de esta revisión sistemática fue registrado en el National Institute of Health Research Database (CRD42021227298). Se realizó una búsqueda bibliográfica de estudios primarios explorando diversas bases de datos electrónicas (Medline vía PubMed, Scopus, Cochrane Library, Science Direct, Web of Science Core Collection, Medline vía Ovid, Lilacs, Embase y literatura gris) Resultados Se encontraron 2189 artículos, tras la lectura de títulos y resúmenes se seleccionaron 63 referencias para examinar y, finalmente, se extrajeron los datos de 15 artículos Conclusiones Se identificó una relación entre el consumo de agua fluorada de pozo y la prevalencia de fluorosis en individuos de hasta 18 años, siendo este estudio el primero en evaluarlo sistemáticamente a nivel mundial.

Fluorosis dental en adolescentes de instituciones educativas de Lima, Perú / Dental fluorosis in adolescents from Educational Institutions in Lima, Peru

Introducción: La fluorosis dental es una patología endémica causada por la ingestión excesiva de fluoruros que pueden producir una alteración durante el desarrollo del esmalte, y es considerado un importante problema de salud pública porque afecta la salud bucal y sistémica de la población. Objetivo: Este estudio tuvo como idea principal determinar la frecuencia y los niveles de fluorosis dental en escolares de 12 a 15 años pertenecientes a dos instituciones educativas de Lima - Perú. Método: Se realizó un estudio descriptivo de tipo transversal, la muestra estuvo conformada por 252 estudiantes, entre 12 y 15 años de dos centros educativos de Lima. El muestreo fue por selección sistemática de elementos muestrales. La fluorosis dental se evalúo mediante el Índice de Dean. Para determinar la frecuencia y los niveles de fluorosis dental, se realizó un examen clínico bucal y se desarrolló un cuestionario validado previamente. Resultados: La frecuencia de fluorosis dental fue de 44,8% (n=113) afectando más a los varones en un 27,39% (n=69) y a los adolescentes de 13 años (15,1%). En relación con los niveles de fluorosis, predominó el tipo "muy leve" (34,9%). También se encontró una asociación entre la presencia y el nivel de fluorosis con el número de aplicaciones de flúor (p<0,05). Además, se dijo que el índice comunitario de fluorosis de Dean fue de 0,43. Conclusiones: En la población escolar evaluada, la frecuencia de fluorosis fue de 44,8% y el nivel predominante de fluorosis fue muy leve. Además, el índice comunitario fue de 0,43, el cual mostró un nivel límite de importancia para la salud pública. Por lo que se puede considerar que el número de aplicaciones tópicas de flúor recibido por la población sin una planificación adecuada se podría convertir en un factor de riesgo para causar fluorosis dental.

Introduction: Dental fluorosis is an endemic pathology caused by the excessive ingestion of fluorides that can produce an alteration during the development of the enamel and is considered an important public health problema because it affects the oral and systemic health of the population. Objective: The objective of this study was to determine the frequency and levels of dental fluorosis in school children between 12 and 15 years of age belonging to two educational institutions in Lima, Peru. Method: A descriptive cross-sectional study was carried out, the sample consisted of 252 students between 12 and 15 years of age from two educational centers in Lima. Sampling was by systematic selection of sample elements. Dental fluorosis was evaluated using the Dean Index. To determine the frequency and levels of dental fluorosis a clinical oral examination was carried out and a previously validated questionnaire was developed. Results: The frequency of dental fluorosis was 44.8% (n=113) affecting more males by 27.39% (n=69) and adolescents aged 13 years (15.1%). In relation to the levels of fluorosis, the "very mild" type predominated (34.9%). An association was also found between the presence and level of fluorosis with the number of fluoride applications (p<0.05). In addition, Dean's community fluorosis index was reported to be 0.43. Conclusions: In the school population evaluated, the frequency of fluorosis was 44.8% and the predominant level of fluorosis was very mild. In addition, the community index was 0.43, which indicated a borderline level of public health importance. Therefore, it can be considered that the number of topical fluoride applications received by the population without adequate planning could become a risk factor for causing dental fluorosis.

Bond strength comparison among 10-MDP-containing and non-10-MDP-Containing adhesives in different degrees of dental fluorosis / Comparación de fuerza de unión entre adhesivos que contienen y no contienen 10-MDP en diferentes grados de fluorosis dental

Dental fluorosis can cause changes in the enamel surface, conditioning its functionality and esthetics. The application of dental adhesives is a treatment option; however, their use on fluorotic teeth can result in limitations. The aim of this study was to compare the shear bond strength of two different adhesives, one with 10-MDP and one without 10-MDP, in different degrees of dental fluorosis.This is an in vitro study on dental enamel samples, a total of 180 samples with the inclusion criteria were treated, randomly divided into two groups of 90, according to the type of dental adhesive, where each group was again divided into three groups of 30 samples, representing different degrees of dental fluorosis according to the Thylstrup-Fejerskov index (Group I: TF1 and TF2; Group II: TF3; Group III: TF4). Normality tests, two-factor ANOVA, and post-hoc tests were used to determine differences between the groups, with a significance level of 95%. As results, a statistically significant difference was shown between the use of dental adhesive with 10-MDP and the three groups of dental fluorosis (p=0.011), in addition, a Tukey post-hoc test on the groups treated with 10-MDP adhesive revealed a statistically significant difference between group I versus group II, and group I versus group III, (p=<0.05). It is concluded that the use of adhesive systems with 10-MDP presents a better shear bond strength on enamel with dental fluorosis grades I and II in the Thylstrup-Fejerskov index.

La fluorosis dental puede ocasionar cambios en la superficie del esmalte, condicionando su funcionalidad y estética, la aplicación de adhesivos dentales es una opción de tratamiento, sin embargo, su uso en dientes fluoroticos puede resultar en limitaciones. El objetivo de este estudio consistió en comparar la fuerza de adhesión a la cizalladura de dos diferentes adhesivos, uno con 10-MDP y otro sin 10-MDP, en diferentes grados de fluorosis dental. Se trata de un estudio in vitro en muestras de esmalte dental, un total de 180 muestras con los criterios de inclusión fueron tratadas, aleatoriamente divididas en dos grupos de 90, de acuerdo al tipo de adhesivo dental, donde cada grupo fue dividido nuevamente en tres grupos de 30 muestras, representando diferentes grados de fluorosis dental según el índice de Thylstrup- Fejerskov (Grupo I: TF1 y TF2; Grupo II: TF3; Grupo III: TF4). Para determinar diferencias entre los grupos se utilizaron pruebas de normalidad, ANOVA de dos factores, y pruebas post-hoc, con un nivel de significancia de 95%. Como resultados, se mostró una diferencia estadísticamente significativa entre el uso de adhesivo dental con 10- MDP y los tres grupos de fluorosis dental (p=0.011), además, una prueba post hoc de Tukey sobre los grupos tratados con adhesivo 10-MDP revelaron una diferencia estadísticamente significativa entre el grupo I frente al grupo II, y el grupo I frente al grupo III, (p=<0.05) Se concluye que el uso de sistemas adhesivos con 10-MDP presentan una mejor resistencia de adhesión al cizallamiento en esmalte con grados de fluorosis dental I y II en el índice de Thylstrup-Fejerskov

Fluorosis dental en la primera infancia: estado del arte

La fluorosis dental se caracteriza por una hipomineralización de la estructura dental causada por ingesta excesiva de flúor sistémico. En la dentición decidua, su diagnóstico precoz es importante, dado que será un predictor para la aparición de lesiones en la dentición permanente. El objetivo de esta revisión fue describir la evidencia científica sobre la fluorosis dental en dentición decidua reportando su etiología y factores relacionados, prevalencia, diagnóstico y tratamiento. Se realizaron búsquedas electrónicas en las bases de datos Pub-Med/Medline, EbscoHost y ScienceDirect (noviembre/2020), utilizando las palabras clave "dental fluorosis", "deciduous teeth", "primary tooth", "primary teeth". El desarrollo de fluorosis dental en dentición decidua se relacionó con la ingesta de múltiples fuentes de flúor principalmente, agua potable, alimentos de la dieta, fórmulas infantiles, suplementos y uso de dentífricos fluorados en dosis inadecuadas. Algunos factores prenatales, como vivir en terrenos montañosos o de gran altitud y habitar en lugares cercanos a minas de combustión de carbón, también fueron asociados. La prevalencia de fluorosis dental reportada en los estudios varió entre 6,2 y 96,6 %, dependiendo principalmente de la concentración de flúor en agua potable. Para el diagnóstico de la fluorosis dental en la dentición decidua se deben considerar características como la localización, aspecto, extensión y color de la lesión, realizando diagnóstico diferencial con otro tipo de defectos en esmalte y dentina. Así mismo, el tratamiento de las lesiones dependerá de la severidad del defecto y condiciones individuales del paciente.

Dental fluorosis is characterized by a hypomineralization of the tooth structure caused by excessive intake of systemic fluoride. In the deciduous dentition, its early diagnosis is important since it will be a predictor for the appearance of lesions in the permanent dentition. The objective of this review was to describe the scientific evidence on dental fluorosis in deciduous dentition, reporting its etiology and related factors, prevalence, diagnosis and treatment. Electronic searches were conducted PubMed / Medline, EbscoHost and ScienceDirect (November / 2020) databases, using the keywords "dental fluorosis", "deciduous teeth", "primary tooth", "primary teeth". The development of Dental fluorosis in deciduous dentition was related to the intake of multiple sources of fluoride mainly; drinking water, diet foods, infant formulas, supplements and the use of luoridated toothpastes in inadequate doses. Some prenatal factors such as living in mountainous or high altitude terrain and living in places near coal-burning mines were also associated. The prevalence of dental fluorosis in early childhood reported in the studies varied between 6.2% and 96.6%, depending mainly on the concentration of fluoride in drinking water. For the diagnosis of dental fluorosis in the deciduous dentition, characteristics such as the location, appearance, extension and color of the lesion must be considered, making a differential diagnosis with other types of enamel and dentin defects. Evenly, the treatment of lesions will depend on the severity defects and individual patient conditions.

Time-course changes of intraosseous environment and shear resistance mechanical properties of jawbone in SD rats with fluorosis / 环境与职业医学

Background At present, a large number of reports focus on the bones of limbs and trunk, while there are few studies on the effect of fluorosis on jawbone which is the inevitable structural basis for the development and treatment of oral diseases. Objective To preliminarily investigate the effect of fluoride exposure on the mechanical properties of jawbone by observing the changes in the intraosseous environment and the maximum load against shearing force (LSFmax) of the jawbone in rats with chronic fluoride treatment. Methods Screening experiment: 48 SD male rats were randomly divided into a control group and three fluoride exposure groups (50, 150, and 250 mg·L−1 fluoride concentration), 12 rats in each group. The fluoride exposure groups were molded by feeding different concentrations of sodium fluoride solution, and the control group drank tap water from Guizhou area. Each group was further divided into 4 subgroups with 3 animals each according to observation time points after 0, 2, 4, and 6 months. The LSFmax of the jawbone was measured with an electronic universal ergometer, the expression of type I collagen (Col1) was shown by Sirius red staining, and the expression of runt-related transcription factor 2 (Runx2) was determined semi-quantitatively by immunohistochemistry at selected time points. Formal experiment: 12 male SD rats were randomly divided into a fluoride exposure group and a control group. The fluoride exposure group were fed with 150 mg·L−1 sodium fluoride solution, and the control group drank tap water from Guizhou. After feeding with fluoride for 5 months, the ergometer was used to measure the LSFmax of the jawbone. Osteoclasts were counted after tartrate resistant acid phosphatase (TRAP) staining. Col1, Runx2, bone morphogenetic protein 2 (BMP-2), alkaline phosphatase (ALP), and cathepsin K (Cath K) were detected semi-quantitatively by immunohistochemistry expression and Sirius red staining. Micro computed tomography (Micro CT) was used to observe the trabecular bone microstructure. Results Screening experiment: The LSFmax of the control group and the 50 mg·L−1 fluoride exposure group reached the peak value at the 2nd month, and the LSFmax of the 50 mg·L−1 fluoride exposure group reached the valley value at the 4th month. The LSFmax of the 150 mg·L−1 fluoride exposure group at the 4th month was higher than that at the 6th month (P<0.05). There was no significant difference in the LSFmax at each time point in the 250 mg·L−1 fluoride exposure group. At the same time point, there was no statistically significant difference in LSFmax among the groups. The Col1 levels of the 50 mg·L−1, 150 mg·L−1, and 250 mg·L−1 fluoride exposure groups were higher than the time point 0 from the 2nd month (P＜0.05). The Runx2 showed no statistically significant difference by concentration or time. Formal experiment: After feeding with 150 mg·L−1 fluoride for 5 months, the LSFmax of the fluoride exposure group was greater than that of the control group (P<0.05). The expressions of Col1, Runx2, BMP2, ALP, and Cath K in the fluorosis exposure group were higher than those in the control group (P<0.05). There were no statistically significant differences in osteoclast count or indicators of bone trabecular microstructure. Conclusion Chronic fluoride exposure may increase the shear strength of jaw bone.

Dose-response relationship between toothpaste soluble fluoride absorbed in the gastrointestinal tract and saliva fluoride secretion

Aim: This study aimed to evaluate if there is a dose-response relationship between toothpaste chemically soluble fluoride absorbed in the gastrointestinal tract and fluoride secreted by saliva, giving support to the use of saliva as surrogate for plasma fluoride. Methods: A 4-phase single blind study was conducted, in which 10 participants were subjected in each phase to one of the assigned treatment groups: group I: fresh sample of a Na2FPO3/CaCO3-based toothpaste with 1,334 µg F/g of total soluble fluoride (TSF) and groups II­IV: aged samples of this toothpaste presenting TSF concentrations of 1,128, 808, and 687 µg F/g, respectively. In all phases, the participants ingested an amount of toothpaste equivalent to 70.0 µg F/Kg body weight, as total fluoride (TF). Saliva and blood samples were collected before (baseline) and up to 180 min after toothpaste ingestion as indicator of fluoride bioavailability. F concentration in saliva and blood plasma was determined with a fluoride ion-specific electrode. The areas under the curve (AUC) of F concentration versus time (AUC = ng F/mL × min) and the peaks of fluoride concentration (Cmax) in saliva and plasma were calculated. Results: A significant correlation between mg of TSF ingested and the AUC (r=0.47; p<0.01), and Cmax (r=0.59; p<0.01) in saliva was found; for TF, the correlation was not significant (p>0.05). In addition, the correlations between plasma and saliva fluoride concentrations were statistically significant for AUC (r=0.55; p<0.01) as for Cmax (r=0.68; p<0.01). Conclusion: The findings support that saliva can be used as a systemic biomarker of bioavailable fluoride present in Na2FPO3/CaCO3-based toothpaste

Fluorotic Enamel Susceptibility to Dental Erosion and Fluoride Treatment

Abstract The purpose of this in vitro study was to test the hypothesis that fluoride treatment can prevent dental erosion on fluorotic enamel of different severities. It followed a 3×2 factorial design, considering a) fluorosis severity: sound (TF0, Thylstrup-Fejerskov Index), mild (TF1-2), moderate (TF3-4); and b) fluoride treatment: 0 (negative control) and 1150ppmF. Human molars with the three fluorosis severities (n=16, each) were selected and randomly assigned to the two fluoride treatments (n=8). Enamel blocks (4×4mm) were prepared from each tooth and subjected to a dental erosion cycling model, for 10 days. The daily cycling protocol consisted of erosive challenges (1% citric acid, pH 2.4), interspersed by periods of immersion in artificial saliva, and three 2-minute treatments with either 0 or 1150ppm F. The enamel volume loss (mm3) was calculated by subtracting values obtained by microtomography before and after cycling. Two-Way ANOVA showed no significant interaction between fluorosis severity and fluoride treatment (p=0.691), and no significant effect for either fluorosis severity (TF0 mean±standard-deviation: 13.5(10-2±0.42(10-2, TF1-2: 1.50(10-2±0.52(10-2, TF3-4: 1.24(10-2±0.52(10-2, p=0.416) or treatment (0ppmF: 1.49(10-2±0.53(10-2; 1150ppmF: 1.21(10-2±0.42(10-2; p=0.093), when evaluated independently. Considering the limitations of this in vitro study, the presence and severity of fluorosis in enamel do not appear to affect its susceptibility to dental erosion. Fluoride treatment was not effective in preventing the development of dental erosion in both sound and fluorotic enamel substrates under our experimental conditions.

Resumo Este estudo in vitro foi testou a hipótese de que o tratamento com flúor pode prevenir a erosão dentária no esmalte fluorótico de diferentes severidades. O objetivo deste estudo foi: investigar o efeito protetor dos fluoretos contra a erosão e abrasão simuladas no esmalte fluorótico. Seguiu um desenho fatorial 3×2, considerando a) severidade da fluorose em 3 níveis: hígido (TF0, Índice Thylstrup-Fejerskov), suave (TF1-2), moderada (TF3-4); b) tratamento com flúor: 0 (controle negativo) e 1150ppmF. Molares humanos com as três severidades de fluorose (n=16, cada) foram selecionados e distribuídos aleatoriamente para os dois tratamentos com flúor (n=8). Blocos de esmalte (4×4mm) foram preparados a partir de cada dente e submetidos a um modelo de ciclo de erosão dentária, por 10 dias. O protocolo de ciclagem diária consistiu em seis desafios erosivos de 5 minutos (1% de ácido cítrico, pH 2,4), intercalados por seis períodos de imersão em saliva artificial e três tratamentos de 2 minutos com 0 ou 1150ppmF. O volume do esmalte perdido foi calculado subtraindo o perfil superficial 3D obtido por microtomografia antes e depois da ciclagem. A ANOVA de dois fatores não mostrou interação significativa entre a severidade da fluorose e o tratamento com flúor (p = 0,691) e nenhum efeito significativo para a severidade da fluorose (TF0 média+/desvio padrão: 13,5(10-2±0,42(10-2, TF1-2: 1,50(10-2±0,52(10-2, TF3-4: 1,24(10-2±0,52(10-2, p=0,416) ou tratamento (0: 1,49(10-2±0,53(10-2; 1150ppmF: 1,21(10-2±0,42(10-2, p=0,093), quando avaliados independentemente. Considerando as limitações deste estudo in vitro, a presença e severidade da fluorose no esmalte não parece afetar sua suscetibilidade à erosão dentária. O tratamento com flúor não foi eficaz na prevenção do desenvolvimento da erosão dentária em esmalte hígido e fluorótico, sob as condições experimentais utilizadas.

Fluorose dentária e determinantes sociais da saúde: Revisão integrativa / Dental fluorosis and social determinants of health: Integrative review / Fluorosis dental y determinantes sociales de la salud: revisión integradora

Objetivo: verificar o desenvolvimento da fluorose dentária e sua relação com os Determinantes Sociais da Saúde (DSS) através de uma revisão integrativa. Método: trata-se de uma revisão integrativa de estudos que abordam os aspectos dos DSS e sua relação com a fluorose dentária. A coleta de dados foi realizada entre o período de agosto de 2020 a abril de 2021. Resultados: dos estudos selecionados de língua portuguesa e inglesa observou-se que o Fluorose Dentária é um problema de saúde pública, de âmbito mundial. Conclusão: Assim, é oportuno pensar que a fluorose dentária pode ser influenciada pelo meio ao qual o indivíduo se insere, suas condições sociais, econômicas, psicológicas e comportamentais devem ser consideradas, conforme o olhar dos DSS.

Objective: to verify the development of dental fluorosis and its relationship with the Social Determinants of Health (SDH) through an integrative review. Method: this is an integrative review of studies that address aspects of DSS and its relationship with dental fluorosis. Data collection was carried out between August 2020 and April 2021. Results: from selected studies in Portuguese and English, it was observed that Dental Fluorosis is a public health problem, worldwide. Conclusion: Thus, it is opportune to think that dental fluorosis can be influenced by the environment in which the individual is inserted, their social, economic, psychological and behavioral conditions must be considered, according to the perspective of the DSS.

Objetivo: verificar el desarrollo de la fluorosis dental y su relación con los determinantes sociales de la salud (DE) a través de una revisión integradora. Método: se trata de una revisión integradora de estudios que abordan los aspectos de las SD y su relación con la fluorosis dental. Los datos fueron recolectados entre agosto de 2020 y abril de 2021. Resultados: a partir de los estudios seleccionados de portugués e inglés, se observó que la fluorosis dental es un problema de salud pública en todo el mundo. Conclusión: Por lo tanto, es oportuno pensar que la fluorosis dental puede estar influenciada por el entorno al que se incluye al individuo, se deben considerar sus condiciones sociales, económicas, psicológicas y de comportamiento, de acuerdo con la mirada del SSD.

Susceptibility of fluorotic enamel to dental erosion-abrasion

Abstract Dental hard tissue conditions can be of pre- or post-eruptive nature, such as enamel fluorosis and erosive tooth wear (ETW), respectively. Dental enamel fluorosis is caused by the chronic and excessive intake of fluoride during enamel development, leading to increased fluoride concentration and increased porosity. ETW has become a common clinical condition and often impairs dental function and aesthetics. This in vitro study tested the hypothesis that fluorotic enamel presents different susceptibility to dental erosion-abrasion. It consisted of a 3×3×2 factorial design, considering a) fluorosis severity: sound (TF0), mild (TF1-2), moderate (TF3-4); b) abrasive challenge: low, medium, and high; and c) erosive challenge: yes or no. A total of 144 human teeth were selected according to the three fluorosis severity levels (n=48), and subdivided into six groups (n = 8) generated by the association of the different erosive and abrasive challenges. Enamel blocks (4×4 mm) were prepared from each tooth and their natural enamel surfaces subjected to an erosion-abrasion cycling model. After cycling, the depth of the lesions in enamel was assessed by profilometry. ANOVA showed that the three-way and two-way interactions among the factors were not significant (p > 0.20). Enamel fluorosis level (p=0.638) and abrasion level (p = 0.390) had no significant effect on lesion depth. Acid exposure caused significantly more enamel surface loss than water (p < 0.001). Considering the limitations of this in vitro study, fluorosis did not affect the susceptibility of enamel to dental erosion-abrasion.

Fluoride in Mozambique: retrospective study / Flúor em Moçambique: estudo retrospectivo

ABSTRACT Objective: The study aims to analyse the fluoride concentration in the water supply of the capital of each province of Mozambique, 2019 and compare with previous data 1978 and 2008. Methods: The water supply in cities of Mozambique were analysed in 1978, 2008 and 2019 and water from Tete's River in 1978 and 2019. The fluoride concentration of the water samples was determined in duplicate, using the ion-sensitive electrode (Orion 9609), coupled to a potentiometer (Procyon, model 720), adopting a significance level of 5%. Results: The average fluoride concentration found in the years 1978, 2008 and 2019 was 0.31, 0.33 and 0.14 mg F/L, respectively. The fluoride concentrations collected from household taps in 1978, 2008 and 2019 were: Cabo Delgado/Pemba (0.62, 0.28 and 0.07 mg F/L), Niassa/Lichinga (0.18, 0.98 and 0.07 mg F/L), Nampula/Nampula (0.18, 0.01 and 0.06 mg F/L), Zambézia/Quelimane (0.81, 0.37 and 0.15 mg F/L), Tete/Tete (1.00, 0.97 and 0 .46 mg F/L), Sofala/Beira (0.00, 0.01 and 0.10mg F/L), Manica/Chimoio (0.04, 0.01 and 0.07 mg F/L), Inhambane/Inhambane (0.00, 0.05 and 0.19 mg F/L), Gaza/Xai-Xai (0.01, 0.06 and 0.06 mg F/L) and Maputo (0.23, 0.36 and 0.23 mg F/L), respectively. In the waters of the Zambeze River was 5.5 mg F/L in 1978 and 0.12 mg F/L in 2019. There was no significant change between the fluoride concentrations in the water collected from the taps during the periods studied (p=0.83), however there was a significant difference in the water collected from the river (p<0.05). Conclusion: Tete' River showed a significant reduction in fluoride concentration, and in the piped water collected in all municipalities, the fluoride content was below optimum.

RESUMO Objetivo: O estudo visa analisar a concentração de flúor no abastecimento de água da capital de cada província de Moçambique, 2019 e comparar com dados anteriores de 1978 e 2008. Métodos: A água de abastecimento das cidades de Moçambique foi analisada em 1978, 2008 e 2019 e a água do Rio Tete em 1978 e 2019. A concentração de flúor das amostras de água foi determinada em duplicata, utilizando o eletrodo íon-sensível (Orion 9609), acoplado a um potenciômetro (Procyon, modelo 720), adotando-se nível de significância de 5%. Resultados: A concentração média de flúor encontrada nos anos de 1978, 2008 e 2019 foi de 0,31, 0,33 e 0,14 mg F/L, respectivamente. As concentrações de flúor recolhidas nas torneiras das casas em 1978, 2008 e 2019 foram: Cabo Delgado/Pemba (0,62, 0,28 e 0,07 mg F/L), Niassa/Lichinga (0,18, 0,98 e 0,07 mg F/L), Nampula/Nampula (0,18, 0,01 e 0,06 mg F/L), Zambézia /Quelimane (0,81, 0,37 e 0,15 mg F/L), Tete/Tete (1,00, 0,97 e 0,46 mg F/L), Sofala/Beira (0,00, 0,01 e 0,10 mg F/L), Manica/Chimoio (0,04, 0,01 e 0,07 mg F/L), Inhambane/Inhambane (0,00 , 0,05 e 0,19 mg F/L), Gaza/Xai-Xai (0,01, 0,06 e 0,06 mg F/L) e Maputo (0,23, 0,36 e 0,23 mg F/L), respectivamente. Nas águas do rio Zambeze foi de 5,5 mg F/L em 1978 e 0,12 mg F/L em 2019. Não houve alteração significativa entre as concentrações de flúor na água coletada das torneiras durante os períodos estudados (p=0,83), porém houve diferença significativa na água captada no Rio (p<0,05). Conclusão: O Rio Tete apresentou redução significativa na concentração de flúor, e na água das torneiras coletada em todas as cidades, o teor de flúor estava abaixo do ideal.

Changes of RAGE/p38MAPK/NF-κB signaling pathway in brain tissue of subchronic fluorosis rats and protective effects of Ginkgo biloba extract and RAGE antagonist / 环境与职业医学

Background Fluorine accumulates in the brain tissue after long-term excessive intake and subsequently cause nerve damage and decline of learning and memory ability. Receptor of advanced glycation end-products (RAGE)/p38 mitogen-activated protein kinase (p38MAPK)/nuclear factor kappa-B (NF-κB) signaling pathway is considered to be involved in the associated mechanism. Objective To study the changes of RAGE/ p38MAPK/ NF-κB signaling pathway in rats with subchronic fluorosis, and to explore the protective effects of extract of Ginkgo biloba 761 (EGb761) and RAGE antagonist (FPS-ZM1) on neuromemory ability. Methods Ninety male clean SD rats were divided into 9 groups with 10 rats in each group. The modeling period was 6 months. Control group (C group): free drinking tap water (fluoride content <0.5 mg·L−1), low- and high-dose fluoride groups (LF group, HF group): free drinking tap water with 10 or 50 mg·L−1 fluoride; intervention group of Ginkgo biloba extract (CE, LFE, and HFE groups): on the basis of the C group, LF group, and HF group, 100 mg·kg−1·d−1 EGb761 was given daily via intragastric administration; FPS-ZM1 intervention groups (CF, LFF, and HFF groups): 7 d before the end of modeling, 1 mg·kg−1·d−1 FPS-ZM1 was injected intraperitoneally daily on the basis of the C group, LF group, and HF group. The contents of fluoride in brain and blood of each group were detected. The learning and memory ability was tested by water maze experiment. The histopathologic changes of the hippocampus were detected by Nissl staining. The protein expression levels of RAGE and its ligand high mobility group protein B1 (HMGB1), NF-κB, p38MAPK, phospho-p38MAPK (p-p38MAPK), interleukin-6 (IL-6), and tumour necrosis factor-α (TNF-α) in brain tissue were detected by Western blotting. The mRNA expression levels of RAGE, HMGB1, and p38MAPK were detected by quantitative real-time PCR. Results Compared with the C group, the contents of blood fluoride and brain fluoride in the LF and the HF groups were increased (P<0.05). The results of the water maze experiment showed that, compared with the C group, the escape latency time of the LF group and the HF group was longer and the crossing times were reduced; compared with the HF group, the escape latency time of the HFE group and the HFF group was shortened, and the crossing times were increased (P<0.05). The Nissl staining results showed that the number of Nissl body in the HF group decreased compared with the C group; compared with the HF group, the number of Nissl body in the HFE group and the HFF group increased. The Western blotting results showed that compared with the relative protein expression levels of RAGE, HMGB1, NF-κB, p38MAPK, p-p38MAPK, IL-6, and TNF-α in the C group , the levels of above indicators in the HF group and the levels of RAGE, HMGB1, NF-κB, p-p38MAPK, and IL-6 in the LF group were up-regulated (P<0.05); compared with the HF group, the levels of above indicators in the HFE group and the HFF group were all down-regulated (P<0.05); compared with the relative protein expression levels of RAGE and HMGB1 in the LF group, the levels in the LFE group and the LFF group were all down-regulated (P<0.05). The quantitative real-time PCR results showed that compared with the C group, the mRNA expression levels of RAGE and HMGB1 in the LF group and the HF group were up-regulated; compared with the LF group, the mRNA expression levels of RAGE in the LFE group and the LFF group were down-regulated ; compared with the HF group, the mRNA expression levels of RAGE and HMGB1 in the HFE group and the HFF group were down-regulated (P<0.05). Conclusion The central nervous system injury caused by subchronic fluorosis may be related to the activation of RAGE/p38-MAPK/NF-κB signaling pathway, which can impair the learning and memory ability of rats, while EGb761 and FPS-ZM1 may have certain protective effects on the nerve injury.

Analysis of investigation results of the prevalence of skeletal fluorosis in drinking-water-borne endemic fluorosis areas in Inner Mongolia Autonomous Region in 2019 / 中华地方病学杂志

Objective:To study the prevalence of skeletal fluorosis in drinking-water-borne endemic fluorosis areas in Inner Mongolia Autonomous Region (Inner Mongolia), and to provide reference for further prevention and treatment of skeletal fluorosis at this stage.Methods:From March to October 2019, a survey of skeletal fluorosis was carried out in all diseased villages of the eight diseased leagues (cities) in Inner Mongolia, including Alxa, Bayannur, Baotou, Ordos, Hohhot, Hulunbeier, Ulanqab and Xilingol. Permanent residents aged 18 years and above in the diseased villeges were investigated. Face to face questionnaires were used to collect the basic data of age, sex, epidemiological history, etc. of all subjects, and clinical examination of skeletal fluorosis was carried out. Drinking water samples were collected from residents for fluoride content testing.Results:A total of 123 166 residents aged 18 years and above were investigated, 1 781 cases of skeletal fluorosis were detected, and the detection rate was 1.45%. The degree of skeletal fluorosis was mild, accounting for 72.26% (1 287/1 781); the others were moderate and severe, accounting for 20.38% (363/1 781) and 7.36% (131/1 781), respectively. There were statistically significant differences in the detection rates of skeletal fluorosis among people of different water fluoride content, age, gender and regions (χ 2 = 565.96, 671.32, 4.38, 17 283.80, P < 0.05). Among them, the detection rates of skeletal fluorosis in water fluoride content > 4.0 mg/L, ≥56 years old and female population were relatively high, which were 5.21% (49/941), 2.26% (1 428/63 188) and 1.52% (905/59 555), respectively. The detection rates of skeletal fluorosis in Xilingol League and Baotou City were significantly higher, 25.48% (745/2 924) and 24.32% (225/925), respectively. Conclusion:The situation of skeletal fluorosis in drinking-water-borne endemic fluorosis areas in Inner Mongolia has been effectively controlled, but there are still relatively many patients with skeletal fluorosis in some areas, and further targeted prevention and control work is needed.

Research progress of the relationship between fluorosis and cardiovascular disease / 中华地方病学杂志

Fluorosis is widely prevalent worldwide, and China is one of the countries with a high incidence of endemic fluorosis. In recent years, study on non skeletal damage caused by fluorosis, especially cardiovascular system damage, has gradually increased. Fluoride can cause cardio vascular arteriosclerosis, hypertension and other diseases, while cardiovascular disease have hidden and acute onset, and the mortality rate has increased year by year in recent years. At present, the mechanism of cardiovascular diseases caused by fluoride is not yet clear, and further clarification is needed. This article provides an overview of the effects of fluoride on cardiovascular diseases from three aspect: epidemiological investigation, animals experiment, and in vitro cell experiment. It categorizes and analyzes the pathogenesis, providing new ideas for the study of cardiovascular system damage caused by fluorosis.

Analysis of surveillance results of drinking water-borne endemic fluorosis in Jiangsu Province in 2021 / 中华地方病学杂志

Objective:To learn about the implementation of prevention and control measures in drinking water-borne endemic fluorosis areas and the trend of the disease change in Jiangsu Province.Methods:In March to October 2021, a general survey was carried out in 1 972 villages with drinking water-borne endemic fluorosis in 27 counties (cities and districts) of Jiangsu Province, the operation of water improvement projects in the villages was monitored, and the water fluoride content was determined. The prevalence of dental fluorosis among children aged 8 to 12 years in all the villages was investigated.Results:The 1 972 villages with drinking water-borne endemic fluorosis had completed water improvement, and all water improvement projects were operating normally and the water was qualified. Among them, 1 774 villages in the disease affected areas had achieved the control goal, accounting for 89.96%; and there were 198 villages in the disease affected areas with control measures up to the standard, accounting for 10.04%. A total of 47 water improvement projects were monitored, including 2 small-scale water improvement projects, accounting for 4.26%. There were 45 large-scale water improvement projects, accounting for 95.74%. A total of 125 790 children aged 8 to 12 years were examined, and 12 625 cases of dental fluorosis were detected. The detection rate of dental fluorosis was 10.04%, and the dental fluorosis index was 0.19. The detection rate of dental fluorosis in children aged 8 to 12 years was 9.98% (1 854/18 579), 10.27% (2 704/26 323), 9.48% (2 765/29 152), 9.73% (2 835/29 145) and 10.92% (2 467/22 591), respectively, with statistically significant difference (χ 2 = 10.51, P = 0.015). Among the 198 villages with control measures up to standard, according to the historical water fluoride, the detection rate of dental fluorosis in children in each water fluoride range (1.20-2.00, 2.01-3.00, 3.01-4.00, > 4.00 mg/L) was 37.73% (698/1 850), 43.17% (1 176/2 724), 45.50% (769/1 690) and 55.20% (802/1 453), respectively, with a statistically significant difference (χ 2 = 104.15, P < 0.001). Conclusion:The water improvement measures in drinking water-borne endemic fluorosis areas in Jiangsu Province have achieved significant results, which still need to be further consolidated.

Progress on the application of porcelain veneers in the restoration of dental fluorosis and its influencing factors / 中华地方病学杂志

Due to the cloud-like appearance of the dental surface of dental fluorosis, serious tooth defect may occur, thus affecting the overall beauty of the face. The clinical effect of dental fluorosis is not better than that of normal teeth in the application of repair, which brings some difficulties to the clinicians. The application of porcelain veneers in the restoration of dental fluorosis has been widely concerned by clinicians and researchers due to its advantages of high aesthetics, small amount of tooth tissue abrasion, and good biocompatibility. Therefore, this article comprehensively discusses the application effect and influencing factors of porcelain veneers in the restoration of dental fluorosis, in order to provide some reference for clinical application.

Progress in molecular signal pathway of dental fluorosis / 中华地方病学杂志

Dental fluorosis is a manifestation of chronic oral fluorosis caused by excessive fluoride intake in childhood. At present, the molecular mechanism of dental fluorosis is still unclear. Ameloblasts are the most sensitive cells to fluoride in tooth tissue. Fluoride affects the proliferation and secretion of ameloblasts through the role of key molecules in the molecular signal pathways, leading to the formation of dental fluorosis. This paper reviews the relationship between the molecular signal pathways [mitogen-activated protein kinase (MAPK), transforming growth factor-β (TGF-β)/Smad, Wnt, Foxo1/Runx2], stress pathways (endoplasmic reticulum stress and oxidative stress) and the occurrence of dental fluorosis in recent years, in order to deeply understand the pathogenesis of dental fluorosis at the molecular level, and provide new ideas for the prevention and treatment of dental fluorosis.

Analysis of influencing factors of dental fluorosis in children based on logistic regression and classification tree model / 中华地方病学杂志

Objective:To analyze the influencing factors of dental fluorosis of children in the drinking-water-borne endemic fluorosis (referred to as drinking-water-borne fluorosis) areas with qualified drinking water.Methods:In 2020 and 2021, the cluster sampling method was used to select the children aged 8 to 12 years old from the drinking-water-borne fluorisis areas with qualified drinking water in Tianjin City for water and urine fluoride detection, dental fluorosis examination and questionnaire survey, and logistic regression and classification tree model were used to analyze the influencing factors of dental fluorosis in children.Results:A total of 3 795 cases children aged 8 to 12 years old were investigated, and 1 001 cases of dental fluorosis were detected, and the detection rate of dental fluorosis was 26.38% (1 001/3 795). The results of logistic analysis showed that age [odds ratio ( OR) = 1.193, 95% confidence interval ( CI): 1.115 - 1.277], high urinary fluoride (1.84 - 19.40 mg/L, OR = 1.510, 95% CI: 1.169 - 1.952) and the number of permanent residents at home ≥6 ( OR = 1.377, 95% CI: 1.090 - 1.739) were risk factors of dental fluorosis in children; and the mother's with higher education level (college degree or above, OR = 0.664, 95% CI: 0.441 - 0.999), the years of water improvement ≥5 years (5 - < 10 years, OR = 0.193, 95% CI: 0.157 - 0.238; ≥10 years, OR = 0.254, 95% CI: 0.193 - 0.333) were protective factors of dental fluorosis in children. The results of classification tree model analysis showed that the years of water improvement contributed the most to the prevalence of dental fluorosis among children in the drinking-water-borne fluorisis areas with qualified drinking water, followed by age, number of permanent residents at home and urinary fluoride. The area under the receiver operating characteristic curve (AUC) of logistic regression model and classification tree model were 0.730 (95% CI: 0.711 - 0.748) and 0.721 (95% CI: 0.702 - 0.739), respectively, with good fitting effect. Conclusion:The detection rate of children's dental fluorosis in the drinking-water-borne fluorosis areas with qualified drinking water is mainly related to the years of water improvement, age, the number of permanent residents at home and urinary fluoride.

Monitoring results of coal-burning-borne endemic fluorosis in Yunnan Province in 2020 / 中华地方病学杂志

Objective:To learn about the current situation of prevention and control of coal-burning-borne endemic fluorosis (coal burning fluorosis for short) in Yunnan Province, and comprehensively evaluate the implementation effect of prevention and control measures.Methods:From August to November 2020, according to the requirements of the Monitoring Program of Yunnan Province for Coal-burning-borne Endemic Fluorosis (2019 edition), monitoring was carried out in all natural villages in the disease areas of 13 counties (cities and districts, hereinafter referred to as counties) of the province, and 30 households were selected from each natural village to monitor the use of stoves and the formation of related healthy living behaviors. At the same time, children aged 8 - 12 years in the natural villages in the disease areas were examined for the prevalence of dental fluorosis. The evaluation for control and elimination of disease areas was carried out in accordance with the Evaluation Approach for Control and Elimination of Priority Endemic Diseases (2019 edition).Results:A total of 392 244 households were investigated, and the rates of qualified improved stoves, the correct utilization of qualified improved stoves and correct drying of corn and pepper were 99.42% (389 982/392 244), 99.70% (388 796/389 982) and 99.07% (388 579/392 244), respectively. A total of 227 057 children aged 8 - 12 years were examined, 9 413 children of dental fluorosis were detected, the detection rate of dental fluorosis was 4.15%, the dental fluorosis index was 0.10, and the prevalence intensity was negative. Taking the county as a unit, except Fuyuan and Zhenxiong, which reached the control standard of the disease area, the remaining 11 counties reached the elimination standard.Conclusion:The prevention and control measures on coal burning fluorosis are implemented well in Yunnan Province and healthy lifestyle has gradually taken shape, with the overall condition of the disease reduced.

Evaluation on the effect of prevention and control of coal-burning-borne endemic fluorosis in Sichuan Province from 2018 to 2021 / 中华地方病学杂志

Objective:To evaluate the effectiveness of prevention and control of coal-burning-borne endemic fluorosis in Sichuan Province, and to provide basis for further development of targeted prevention and control measures.Methods:According to the requirements of the Implementation Plan for the Elimination and Evaluation of Coal-burning-borne Endemic Fluorosis in Sichuan Province, from 2018 to 2021, the assessment of the elimination of coal-burning-borne endemic fluorosis was carried out in all the endemic fluorosis villages of 23 counties (cities, districts) in Sichuan Province. In each village, 30 households were selected to be investigated the use of improved stoves, the drying of corn and pepper for human consumption, and the prevalence of dental fluorosis among all children aged 8 - 12 years old in the village.Results:A total of 222 242 households were surveyed in 1 640 villages, 196 towns, 23 counties (cities, districts) in Sichuan Province. Among them, the rate of qualified improved stoves was 99.99% (222 238/222 242), the correct use rate of qualified improved stoves was 99.90% (212 026/222 238), and the correct drying rate of corn and pepper for human consumption was 99.96% (212 630/212 721). A total of 135 125 children aged 8 to 12 years old were examined, and 5 927 cases of dental fluorosis were detected. The prevalence of dental fluorosis in children was 4.39%. The grading of dental fluorosis was mainly very mild and mild, which were 2.71% (3 656/135 125) and 1.32% (1 783/135 125), respectively. In the county-level self-assessment of 1 640 villages, 1 621 villages had reached the elimination standard, with the elimination rate of 98.84%. Taking counties as a unit, the elimination rate of diseased villages ranged from 96.69% to 100.00%, and 23 diseased counties (cities, districts) had reached the elimination standard. In the provincial-level review results of 174 villages with endemic fluorosis, 174 diseased villages had reached the elimination standard, with the consistency rate of 98.85% (172/174) with the county-level self-assessment results. Among them, except for Gulin County, the consistency rate of self-assessment results was 7/9, the consistency rate of other counties (cities, districts) was 100.00%.Conclusions:The prevention and control of coal-burning-borne endemic fluorosis in Sichuan Province has achieved remarkable results, and all the diseased counties (cities, districts) have reached the elimination standard. In the future, we should continue to take active prevention and control measures to ensure that the elimination status is maintained.

Influence of dietary composition of residents in endemic fluorosis area on the prevalence of skeletal fluorosis / 中华地方病学杂志

Objective:To analyze the relationship between dietary composition of residents in endemic fluorosis areas and skeletal fluorosis.Methods:A case-control study was used to analyze the difference of dietary composition between patients with skeletal fluorosis (case group) and residents without skeletal fluorosis (control group). In August 2019, taking the drinking water-borne endemic fluorosis area in Wenshui County, Lvliang City, Shanxi Province as the survey site, a cluster sampling method was adopted to select local residents aged over 18 years old, and a questionnaire survey was conducted by face-to-face interview. The survey contents included gender, age and consumption frequency of various foods. Binary logistic regression was used to analyze the relationship between food consumption frequency and skeletal fluorosis. The diagnosis of skeletal fluorosis was made by using portable digital radiography (DR) to take X-ray films of forearm and lower leg, combining with clinical signs, and according to the Diagnostic Standard for Endemic Skeletal Fluorosis (WS/T 192-2008) to determine.Results:A total of 1 061 subjects were included in this study, including 376 in the case group and 685 in the control group. The age composition of patients in the case group (≤60, > 60 years old: 162, 214 cases) was significantly different from that in the control group (≤60, > 60 years old: 423, 261 cases, χ 2 = 34.52, P < 0.001). There was no statistically significant difference in gender ratio (χ 2 = 1.37, P = 0.251). The proportion of patients in the case group who ate meat and eggs > 1 time/week was lower than that in the control group (χ 2 = 8.06, 5.46, P < 0.05), the proportion of patients who ate milk > 1 time/week was higher than that in the control group (χ 2 = 4.01, P = 0.046), and the proportion of patients who ate seafood ≥1 time/week was lower than that in the control group (χ 2 = 4.16, P = 0.046). The results of binary logistic regression analysis showed that after adjusting for age, sex, and urinary fluoride, the frequency of eating meat, eggs or milk > 1 time/week and the frequency of eating seafood ≥1 time/week were not related to the risk of skeletal fluorosis ( P > 0.05); however, in the group ≤60 years old, the frequency of eating eggs > 1 time/week was associated with the risk of skeletal fluorosis [odds ratio ( OR) = 0.59, 95% confidence interval ( CI): 0.39, 0.88]. Conclusions:The consumption frequency of meat, milk, eggs and seafood is significantly different between the skeletal fluorosis patients and the control people. In the population ≤60 years old, consumption frequency of eggs > 1 time/week may reduce the risk of skeletal fluorosis.