Nivel de conocimiento de los padres sobre el uso de pastas dentales en asociación con la ingesta estimada de fluoruro en niños / Level of knowledge in parents about the use of toothpaste in association with estimated fluoride intake in children

Resumen Introducción: Diversos estudios han demostrado que los padres aún no cuentan con el conocimiento suficiente sobre el uso de pastas dentales que deben consumir sus hijos. Muchos de ellos desconocen desde que edad se debe empezar con el uso de pastas dentales, la cantidad exacta que se debe colocar en el cepillo y sobre todo con qué frecuencia se deben cepillar. Objetivo: Asociar el nivel de conocimiento de los padres sobre el uso de pastas dentales con las características asociadas a la ingesta estimada de fluoruro en niños entre los 6 meses a 8 años de Lima Metropolitana y Callao. Materiales y métodos: Estudio de tipo observacional, descriptivo y transversal. Se realizó el cuestionario a 264 padres de familia residentes en Lima Metropolitana y Callao durante los meses de julio a septiembre del 2020. Se calcularon las frecuencias absolutas y relativas. Para el análisis bivariado, se utilizó la prueba de Chi cuadrado de El nivel de significancia estadística fue de 0.05. Resultados: Se observa que el 52.94% de los padres, así como el 60.41% de las madres presentan un nivel medio de conocimiento sobre el uso de pastas dentales con flúor. Además, se obtuvo que el 56.25% de los padres que afirmaron que sus hijos no se enjuagan con agua después del cepillado presentan un nivel alto de conocimiento sobre el uso de pastas dentales con flúor. Conclusión: Se obtuvo que el 57.58% de los padres tenían un nivel medio de conocimiento sobre el uso de pastas dentales con flúor. Se encontró asociación entre el nivel de conocimiento sobre el uso de pastas dentales con flúor y las características asociadas a la ingesta estimada de fluoruro.

Abstract Introduction: Various studies have shown that parents still do not have sufficient knowledge about the use of toothpastes that their children should consume. Many of them do not know from what age to start using toothpastes, the exact amount to be placed on the brush and especially how often they should be brushed. Aim: To associate the level of knowledge of parents about the use of toothpastes with the characteristics associated with the estimated intake of fluoride in children between 6 months to 8 years of Metropolitan Lima and Callao. Materials and methods: An observational, descriptive, and crosssectional study. The questionnaire was carried out on 264 parents residing in Metropolitan Lima and Callao during the months of July to September 2020. The absolute and relative frequencies were calculated. For the bivariate analysis, the Chi-square test of the level of statistical significance was used was 0.05. Results: It is observed that 52.94% of the fathers, as well as 60.41% of the mothers present a medium level of knowledge about the use of fluoride toothpastes. In addition, it was found that 56.25% of parents who stated that their children do not rinse with water after brushing have a high level of knowledge about the use of fluoride toothpastes. Conclusion: It was found that the 57.58% of parents had a median level of knowledge about the use of fluoride toothpastes. An association was found between the level of knowledge about the use of fluoride toothpastes and the characteristics associated with the estimated fluoride intake.

Effectiveness evaluation of health education on drinking-water-borne endemic fluorosis in Jiangsu Province from 2014 to 2018 / 中华地方病学杂志

Objective:To evaluate the effect of health education on drinking-warter-borne endemic fluorosis in Jiangsu Province.Methods:From 2014 to 2018, a total of 12 counties (districts) with drinking-warter-borne endemic fluorosis were selected to carry out public health education activities, and 3 townships were chosen in each project county (district). School health education activities were carried out in the classes of grade 4 - 6 in the central primary school in each selected twonship. In the meantime, 3 villages were chosen in each selected township where the health education activities in the community were carried out. Before and after the health education activities, questionnaire surveys on knowledge of drinking-warter-borne endemic fluorosis prevention were conducted among 30 students in one class of grade 5 in the central primary school and 15 housewives lived near the central primary school in each township.Results:After the health education activities, the rates of knowledge awareness in the students and the housewives were 94.83% (15 362/16 200) and 95.14% (7 706/8 100), respectively, which were significantly higher than those before the health education activities [63.88% (10 348/16 200) and 65.94% (5 341/8 100)], and the differences were statistically significant (χ 2 = 4 700.00, 2 200.00, P < 0.001). There were no statistical differences in the rates of knowledge awareness in the students and housewives before the health education activities from 2014 to 2018 (χ 2 = 8.43, 0.88, P = 0.077, 0.928). Before the health education activities, the rate of knowledge awareness in the students was lower than that in the housewives, and the difference was statistically significant (χ 2 = 10.03, P = 0.002). After the health education activities, there was no statistical difference between the rate of knowledge awareness in the students and that in the housewives (χ 2 = 1.07, P = 0.301). Conclusions:The rates of knowledge awareness in the students and the housewives are increased significantly after the health education activities. We should expand the coverage of health education. Wide, deep and persistent health education in more ways for different people are needed to consolidate the achievements.

Expressions of Col-Ⅰ, Col-Ⅲ and α-SMA in liver of rats with chronic fluorosis / 中华地方病学杂志

Objective:To explore whether chronic fluorosis can cause liver fibrosis in rats by observing expression changes in type Ⅰcollagen (Col-Ⅰ), type Ⅲ collagen (Col-Ⅲ) and alpha smooth actin (α-SMA) in the liver tissue of chronic fluorosis rats.Methods:According to body weight (90 - 100 g), forty-eight SD rats were randomly divided into control group (drinking water fluoride ion concentration < 0.5 mg/L), low, medium and high concentration fluoride groups (drinking water fluoride ion concentration of 5.0, 50.0 and 100.0 mg/L), with 12 rats in each group (half male and half female), and fed for 6 months. Fluoride ion selective electrode method was used to detect bone fluoride and urinary fluoride levels; hematoxylin-eosin staining (HE staining) and Masson staining were used to observe the pathological and morphological changes and the collagen deposition of liver tissue; quantitative real-time polymerase chain reaction and immunohistochemical staining were used to observe Col-Ⅰ, Col-Ⅲ and α-SMA mRNA and protein expressions.Results:There was significant difference in bone fluoride and urine fluoride between the 4 groups [bone fluoride: (92.52 ± 5.64), (112.21 ± 11.86), (142.99 ± 7.87), (235.63 ± 11.55) mg/kg; urinary fluoride: (5.47 ± 0.88), (17.78 ± 1.48), (54.16 ± 5.96), (121.11 ± 6.32) mg/L, P < 0.001]. Under light microscope, with the increase of fluoride concentration, the degree of hepatic cell edema was aggravated, and the deposition of collagen fiber around the central vein and the portal area increased significantly. The mRNA expression level of Col-Ⅰ in low, medium and high concentration fluoride groups (1.20 ± 0.09, 1.80 ± 0.08, 1.58 ± 0.06) was significantly higher than that in control group (1.00 ± 0.00, P < 0.05); Col-Ⅲ and α-SMA mRNA expression levels in medium and high concentration fluoride groups (Col-Ⅲ: 1.15 ± 0.14, 1.64 ± 0.24; α-SMA: 1.69 ± 0.02, 2.34 ± 0.06) were significantly higher than those of low concentration fluoride group (Col-Ⅲ: 0.59 ± 0.17; α-SMA: 0.80 ± 0.13, P < 0.05). With the increase of fluoride concentration, the liver tissue Col-Ⅰ(0.00 ± 0.00, 0.03 ± 0.01, 0.08 ± 0.01, 0.13 ± 0.02), Col-Ⅲ (17 803.05 ± 3 221.16, 47 523.15 ± 3 490.10, 127 786.35 ± 13 008.86, 237 233.03 ± 47 614.63) and α-SMA (516.83 ± 181.18, 2 885.03 ± 864.92, 11 186.94 ± 2 394.08, 37 182.43 ± 12 390.59) protein levels were also increased significantly ( P < 0.05). Conclusion:Long-term excessive intake of fluorine may cause the production of collagen fibers around the central vein and the portal area of the liver in rats to increase, and then lead to the formation of liver fibrosis.

Effects of excessive fluoride exposure on astrocytes and the expression of glial fibrillary acidic protein in vitro and in vivo / 中华地方病学杂志

Objective:To investigate the effects of excessive fluoride exposure on astrocytes and the expression of glial fibrillary acidic protein (GFAP), in vitro and in vivo. Methods:(1) In vivo experiment: 24 SPF SD rats, half male and half female, were randomly divided into control and fluoride exposed groups according to sex and body weight, 12 rats in each group. Rats were fed with < 1 mg/L and 50 mg/L sodium fluoride solution prepared by tap water for 6 months, respectively. The expression levels of GFAP protein in rat brain tissue were measured by immunofluorescence, immunohistochemistry and Western blotting. (2) In vitro experiment: adult (6-month-old) rat cortical astrocytes were extracted and cultured in primary culture (4 mmol/L sodium fluoride solution for 24 h), and the astrocytes were identified by immunofluorescence, and GFAP mRNA and protein expression levels were detected by real-time fluorescence quantitative PCR and Western blotting, respectively, and astrocytes apoptosis and calcium ion content were detected by flow cytometry. Results:(1) In vivo experiment: the results of immunofluorescence, immunohistochemistry and Western blotting showed that the GFAP protein expression level in brain tissue of rats exposed to fluoride was higher than that of control group (0.440 ± 0.200 vs 0.250 ± 0.120, t =-5.93, P = 0.027; 0.270 ± 0.020 vs 0.240 ± 0.050, t =-4.87, P = 0.040; 1.017 ± 0.001 vs 0.486 ± 0.006, t =-52.48, P = 0.001). (2) In vitro experiment: GFAP positive cells were identified as astrocytes by immunofluorescence; GFAP mRNA expression level was higher in fluoride exposed group than that of control group by real-time fluorescence quantitative PCR (2.780 ± 0.120 vs 0.134 ± 0.005, t =-37.84, P = 0.001). The Western blotting results showed that the GFAP protein expression level was higher in fluoride exposed group than that of control group (2.76 ± 0.10 vs 1.38 ± 0.05, t =-20.44, P = 0.002). Flow cytometry results showed that the apoptosis rate of astrocytes was higher in fluoride exposed group than that of control group (%: 55.0 ± 1.0 vs 3.5 ± 0.6, t =-10.28, P = 0.009) and the calcium ion content was lower than that of control group (%: 54 ± 9 vs 72 ± 13, t = 4.64, P = 0.043). Conclusion:Excessive fluoride exposure causes increased GFAP expression in astrocytes in vitro and in vivo, promotes apoptosis, and affects calcium signaling pathways.

Investigation and analysis on epidemic status of tea-drinking-borne endemic fluorosis in Gansu Province from 2019 to 2020 / 中华地方病学杂志

Objective:To analyze the epidemic range of tea-drinking-borne endemic fluorosis in Gansu Province and accurately grasp the information of tea-drinking-borne endemic fluorosis patients, so as to provide basis for popularizing low fluorine brick tea and carrying out patient rescue and treatment.Methods:From 2019 to 2020, 12 counties (cities) in Gansu Province with a history of drinking brick tea were selected as the survey points according to the "Investigation Plan of Endemic Fluorosis of Tea Drinking Type in China in 2019" and the relevant information in Gansu Province. A cross-sectional survey was conducted in all villages with the habit of drinking brick tea (including the investigation of the fluoride content in drinking water, tea, the fluoride intake of the population, the dental fluorosis and urinary fluoride content of children aged 8 to 12, and the skeletal fluorosis and urinary fluoride content of adults), and the survey results were analyzed.Results:The survey covered 125 townships in 12 counties (cities), with 8 625 households in 860 villages. One thousand six hundred and seventy-two drinking water samples were collected, and the fluoride content in water ranged from 0.01 to 1.81 mg/L. Six villages with fluoride content > 1.0 mg/L were screened. A total of 3 664 tea samples were collected, the average fluorine content of brick tea was 481.33 mg/kg, and the fluorine content ranged from 31.88 to 1 643.40 mg/kg. There were 1 076 tea samples with fluorine content less than 300 mg/kg, and the qualified rate of fluorine content in brick tea was 29.37% (1 076/3 664). Among the 12 counties (cities), 92 townships and 496 villages were still drinking brick tea. The drinking rate of brick tea in villages was 57.67% (496/860), and the annual per capita consumption of brick tea was 1.21 kg. The average daily intake of tea fluoride in adults was 1.57 mg/d. In Maqu County, Aksai County, Tianzhu County and Sunan County, the daily intake of tea fluoride of adults in 31 villages of 13 townships was more than 3.5 mg, involving 5 272 households and 15 272 people. Sixty-five patients with dental fluorosis were found in the above 31 villages. The detection rate of dental fluorosis was 3.50% (65/1 856), mainly in very mild and mild cases. Urine samples were collected from 326 children. The median of urinary fluoride was 1.44 mg/L. The clinical investigation of skeletal fluorosis was carried out in 2 189 adults. X-ray examination of bones and joints was performed in 123 patients with definite clinical symptoms and/or signs of skeletal fluorosis. Seven cases of skeletal fluorosis were positive, the detection rate was 0.32% (7/2 189). Urine samples were collected from 83 adults. The median of urinary fluoride was 1.83 mg/L. Two villages with moderate disease were identified as Yehuwan Village in Anyuan Town of Tianzhu County and Nannigou Village in Zhuaxixiulong Town. Four villages in the mild diseased areas were identified as Daiqian Village in Zhuaxixiulong Town, Xiding Village in Dahonggou Town, Tuta Village in Danma Township of Tianzhu County and Annanba Village in Akeqi Township of Akesai County.Conclusion:Most of the endemic areas of tea-drinking-borne endemic fluorosis in Gansu Province have been under control, but the risk of tea fluoride exposure still exists in some areas, so it is urgent to take targeted prevention and control measures.

Produção científica sobre fluorose em regiões endêmicas: estudo bibliométrico de Anais das Reuniões da Sociedade Brasileira de Pesquisa Odontológica / Scientific production on fluorosis in endemic regions: bibliometric study of Meeting Annals of the Brazilian Society of Dental Research

Objetivo: Identificar os resumos publicados nas Reuniões Anuais da Sociedade Brasileira de Pesquisa Odontológica sobre fluorose em regiões endêmicas e verificar a contribuição da Ciência Brasileira para o assunto. Métodos: Este estudo descritivo foi realizado com dados secundários do período entre 2005 e 2020; os estudos elegíveis foram identificados a partir dos descritores presentes no título e/ou resumo: flúor, fluorose, fluorose dental, fluorose dentária, fluoretação, intoxicação por flúor. Critérios de inclusão: estudos em regiões declaradas como de fluorose endêmica ou que citassem o teor de flúor acima de 0,8 mg F/L. Foram excluídos estudos que não declarassem estudar fluorose em regiões endêmicas ou não citassem o teor de flúor na água. Os dados foram coletados por dois examinadores de modo independente e a distribuição de frequências dos dados foi realizada (Microsoft Excel para Mac v.16.16.12). Resultados: Observou-se que de 41.953 resumos publicados durante esses 15 anos, 1190 (2,83%) foram elegíveis; 426 (1,01%) abordaram especificamente o tema fluorose e24 (0,06%) a fluorose em regiões endêmicas. Os assuntos abordados envolveram tratamento (n = 4; 14,81%); desenvolvimento de programas de promoção de saúde bucal (n = 2; 7,69%);avaliação da potabilidade da água (n = 2; 7,41%); implementação de sistemas de desfluoretação (n = 2; 7,41%); prevalência e severidade (n = 2; 7,41%); distribuição da fluorose na dentição (n = 1, 3,70%); impacto na qualidade de vida (n = 2; 7,41%); percepçãoestética(n = 5; 18,52%); uso e ingestão de flúor (n = 3; 11,11%); fluorose óssea (n = 2; 7,41%); análise da possibilidade de alteração no padrão cognitivo (n = 1; 3,70%), nas funções motoras e no equilíbrio (n=1; 3,70%).Conclusão: Diferentes aspectos relacionados à fluorose em região endêmica foram abordados. A Ciência Brasileira tem se dedicado ao tema ao longo dos anos. Entretanto, há um número restrito de estudos, em especial sobre a relação dose-reposta.

Aim: Identify the abstracts published at the Brazilian Society for Dental Research's Annual Meetings regarding Fluorosis in endemic regions, as well as verify the contribution of Brazilian science to the subject. Methods:This descriptive study was conducted using secondary data from the period between 2005 and 2020; the eligible studies were identified from the descriptors present in the title and/or abstract, as follows: fluoride, fluorosis, dental fluorosis, dental fluorosis, fluoridation, fluoride poisoning. Inclusion criteria: studies in regions with endemic fluorosis were included. Studies that did not address fluorosis in endemic regions were excluded. Data were collected by two independent examiners and the distribution frequency of the data was performed (Microsoft Excel for Mac v.16.16.12). Results: It was observed that of the 41,953 abstracts published during these 15 years, 1,190 (2.83%) were eligible; 426 (1.01%) specifically addressed the theme of fluorosis, and of these, 24 (0.06%) reported on fluorosis in endemic regions. The subjects addressed involved treatment (n = 4; 14.41%), the development of oral health promotion programs (n = 2; 7.41%), the evaluation of water potability (n = 2; 7.41%), the implementation of defluoridation systems (n = 2; 7.41%), prevalence and severity (n = 2; 7.41%), the distribution of fluorosis in dentition (n = 1, 3.70%), impacts on the quality of life (n = 2; 7.41%), esthetic perceptions (n = 4; 18.52%), fluoride use and ingestion (n = 3; 11.11%), bone fluorosis (n = 2; 7.41%), the analysis of alterations in the cognitive pattern (n = 1; 3.70%) and change in motor functions and balance (n=1; 3,70%).Conclusion: Different aspects related to fluorosis in an endemic region were addressed. Brazilian Science has been devoted to the theme over the years; however, there have been a limited number of studies published in the literature concerning the dose-response ratio.

Caracterización geográfica de la exposición a fluoruros en Colombia, mediante uso de fuentes de información de vigilancia en salud pública, durante 2012 ­ 2018 / Geographic characterization of fluorides exposure in Colombia, using public health surveillance information sources, during 2012 ­ 2018

Objetivo: caracterizar geográficamente, en territorio colombiano, las fuentes de agua potable y los índices colectivos de fluorosis dental que indican exposición a fluoruro a nivel comunitario. Métodos: se realizó un estudio descriptivo a partir de dos fuentes de información: el Subsistema de Información de Vigilancia de Calidad de Agua Potable (SIVICAP) y el Sistema de Vigilancia en Salud Pública (Sivigila). Los análisis se realizaron desde 2012 hasta 2018, implementando ponderación de los riesgos por exposición a fluoruro en agua para determinar los siguientes niveles de riesgo: sin riesgo, riesgo para fluorosis dental y riesgo para fluorosis esquelética. Se cálculo el índice colectivo de fluorosis (ICF) dental y se presentaron los resultados en mapas geográficos. Resultados: los departamentos de Nariño, Boyacá, Quindío, Valle del Cauca y Cundinamarca presentaron el mayor número de muestras de agua analizadas (60,5 %); 14 presentaron concentraciones superiores a 4 ppm y 10 municipios concentraciones entre 1,01 y 4 ppm. La vigilancia centinela de la exposición a flúor mostró que 3 municipios presentaron ICF >3, lo que significa un riesgo muy grave. En cuanto al riesgo grave se encontraron 52 municipios de 21 departamentos, principalmente en la región Andina y Caribe. Nariño fue el departamento con mayor número de municipios en riesgo grave. Conclusiones: se identificaron riesgos ambientales en agua, y biológicos por altos índices colectivos de fluorosis dental, que, espacialmente, se ubican en la región Andina, aunque los riesgos en agua se pueden explicar porque en esta región se realiza con mayor frecuencia vigilancia de calidad del agua.

Objective: To geographically characterize in colombian territory, drinking water sources and the collective indices of dental fluorosis which indicate fluoride exposure at the community level. Methods: A descriptive study was carried out from two sources of information: the drinking water quality surveillance information subsystem (SIVICAP) and the public health surveillance system (Sivigila). The analyzes were performed from 2012 to 2018, weighting the risks for exposure to fluoride in water, to determine the following risk levels: no risk, dental fluorosis risk and risk for skeletal fluorosis. The collective dental fluorosis index (ICF) was calculated, the results were represented on geographical maps. Results: the departments of Nariño, Boyacá, Quindío, Valle del Cauca and Cundinamarca presented the highest number of water samples (60.5%). 14 municipalities had concentrations above 4 ppm, and 10 municipalities had concentrations between 1.01 and 4 ppm. Sentinel surveillance of fluoride exposure showed that three municipalities presented ICF> 3, meaning a very serious risk. Regarding serious risk, 52 municipalities from 21 departments were found, mainly in the Andean and Caribbean region. Nariño was the department with the highest number of municipalities at serious risk. Conclusions: environmental risks in water and biological risks were identified due to high collective indices of dental fluorosis, which are spatially located in the Andean region. The risks in water can be explained because in this region water quality surveillance is carried out more frequently.

Expression of GFAP, β-tubulin Ⅲ and synaptophsin and intervention effects of chondroitin sulfate in brain of rats with chronic fluorosis / 中华地方病学杂志

Objective:To observe the expression levels of glial fibrillary acidic protein (GFAP), β-tubulin Ⅲ and synaptophsin, and explore the role of tripartite synapse in the mechanism of central nervous system (CNS) injury and the neuroprotective effect of chondroitin sulfate (CS).Methods:One month old clean grade, 48 female Sparague-Dawley rats and 48 male Sparague-Dawley rats, were randomly divided into 8 groups according to body weight (90 - 120 g) by random number table method, with 12 rats in each group, half male and half female. These rats were fed with water containing different concentrations of sodium fluoride (NaF) [ < 0.5 mg/L (control, CN), 10.0 mg/L (low dose fluoride, LF) and 50.0 mg/L (high dose fluoride, HF)]. Some rats were fed directly for 185 days (CN, LF and HF groups). In addition, rats of CN + normal saline (NS), LF + NS, HF + NS groups and LF + CS, HF + CS groups, were intraperitoneally injected with NS or 0.66 mg/kg CS for 5 consecutive days after 180 days of feeding. After the experiment, the pathological changes of hippocampal CA4 of brain tissue in each group were observed by hematoxylin eosin staining under light microscope, and the expression and distribution of GFAP, β-tubulin Ⅲ and synaptophsin in hippocampal CA4 of rats were detected by immunohistochemistry, the expression of GFAP, β-tubulin Ⅲ and synaptophsin at protein level in hippocampus of rats were detected by Western blotting.Results:Under light microscope, eosinophilic change, loss and irregular arrangement of neuron in the hippocampal CA4 were observed in LF, HF, LF + NS and HF + NS groups. The morphology of LF + CS and HF + CS groups was not significantly changed compared with CN group, but was significant changed compared with LF, HF, LF + NS and HF + NS groups. Immunohistochemical results showed that the rates of positive area of GFAP, β-tubulin Ⅲ and synaptophsin in female and male rats in LF and HF groups were significantly decreased than those in CN group ( P < 0.05); the positive area rates of female and male rats in LF + CS and HF + CS groups were higher than those in LF and HF groups, respectively ( P < 0.05). Western blotting results showed that the proten expression levels of GFAP, β-tubulin Ⅲ and synaptophsin of female and male rats in LF and HF groups (LF group: 0.90 ± 0.09, 0.82 ± 0.08, 1.43 ± 0.14, 0.92 ± 0.02, 1.21 ± 0.15, 0.87 ± 0.02, HF group: 0.58 ± 0.14, 0.73 ± 0.03, 0.63 ± 0.06, 0.67 ± 0.03, 0.87 ± 0.04, 0.70 ± 0.05) were lower than those in CN group (1.24 ± 0.08, 1.09 ± 0.10, 2.64 ± 0.30, 1.54 ± 0.09, 1.72 ± 0.10, 1.13 ± 0.06, P < 0.05). Conclusions:The tripartite synapse and extracellular matrix may take part in pathogenesis of the damages of CNS results from chronic fluorosis; CS may reduce the injury to a certain extent.

Variations of serum bone resorption biomarkers of children of the coal-burning fluorosis area / 中国学校卫生

Objective@#To investigate the concentration of serum bone resorption markers NTX and TRACP-5b of children aged 8-14 years in a coal-burning fluorosis area and its relationship with age, and to provide population data for the study of pathogenesis of skeletal fluorosis.@*Methods@#Totally 123 children of 8-14 schoolage in the two primary schools in Doujing Township, Shuicheng County, Liupanshui City, Guizhou Province were randomly selected as the exposed group. According to the matching principle, 64 children were randomly selected as a control from a primary school in a nondisease area Huaga Town. The dental fluorosis was investigated, and the concentrations of serum NTX and TRACP-5b were measured.@*Results@#The detection rate of dental fluorosis in the fluorosis area was 94.3% and 0 in the control area. The concentrations of serum NTX in fluorosis area children were 13.04 (10.76, 15.64), 14.82 (12.15, 18.26)nmol/L in the early adolescence and middle-aged period, which lower than the control area 15.73(14.36, 18.61), 16.45(15.45, 22.02)nmol/L( P <0.05); The serum TRACP-5b levels in children with fluorosis were 276.74(237.63, 312.75), 270.14(242.82, 321.97), 305.95(259.78, 339.87)nmol/L in prepubertal, early adolescence and middle youth, lower than the control area 370.88 (304.47, 452.84), 353.30 (262.05, 393.19), 420.22 (376.96, 544.60)nmol/L( Z =-3.03, -2.66, -3.10, P <0.05). Serum NTx and TRACP-5b in fluorosis area were negatively correlated with dental fluorosis in children( r =-0.51, -0.37, P <0.01).@*Conclusion@#Fluorosis can reduce the concentrations of serum bone resorption markers NTX and TRACP-5b in children of different age groups. TRACP-5b may be more sensitive to fluoride exposure than NTX, but the specific mechanism remains to be further studied.

Efeitos da toxicidade sistêmica produzida pelo flúor: estudo em modelo animal / Effects of systemic toxicity produced by fluoride: in vivo study

Este estudo buscou verificar possíveis alterações sistêmicas causadas pelo flúor administrado em diferentes concentrações. Foi utilizado um modelo de estudo animal, no qual foram selecionados 60 rattus norvegicus, aleatoriamente divididos em 4 grupos, sendo três grupos testes (receberam água fluoretada nas concentrações de 0,7 ppm F; 1,2 ppm F e 2,0 ppm F), e um grupo controle que recebeu água destilada. Para análise histomorfológica por microscopia óptica, os ratos foram submetidos a dissecação dos seguintes órgãos: intestino alto (duodeno), rim e fígado. Os resultados obtidos após a avaliação descritiva comparativa dos grupos de estudo evidenciaram alterações morfológicas em todos os grupos testes, concluindo, desta forma, que o flúor administrado, nestas concentrações, pode ser tóxico.

This study sought to verify possible systemic changes caused by fluoride administered at different concentrations. An animal model was used in which 60 rattus norvegicus were randomly divided into 4 groups, with three test groups receiving fluoridated water at the different concentrations (0.7 ppm F, 1.2 ppm F and 2, 0 ppm F), and a control group receiving distilled water. A histomorphological analysis was performed by light microscopy after the dissection of the following rat organs: the large intestine (duodenum), the kidney and the liver. The results obtained after the comparative descriptive evaluation of the study groups showed morphological changes in all the test groups, concluding that the fluoride administered at these concentrations could be toxic.

The expression changes of p53 and p21 in female rats of premature ovarian failure in fluorosis / 重庆医学

Objective To investigate the expression changes of p53 and p21 in premature ovarian failure in female rats exposed to coal burning fluorosis.Methods Ablactation 24 SD female rats were chosen to establish animal model (the model group),in fluorine 90 days were put to death.Observed the changes of the teeth of the female rats during fluorine exposure and ovarian granulosa cell premature aging change,detected fluorine contents of urine and bone,and expression of the ovarian granular cell gene p53 and p21.Results In the model group,fluorine spot tooth,the fluorine contents of urine and bone increased significantly.In the model group,there was no premature aging of ovarian granulosa cells in the low fluorine group,but with the increase of dye fluorine metering,ovarian granulosa cells became mild,moderate to severe progressive edema trends,cells morphological damaged fuzzy,and atresia follicles increased significantly,corpus luteum degraded,mature follicle significantly reduced,and the ovarian function gradually signs of premature aging presented.With the increase of dye fluoride measurement,the expression of aging gene p53 and p21 in each group gradually increased,compared with the control group,there was statistically significant difference (P＜0.05).Conclusion Premature ovarian failure caused by coal-burning fluorosis was significantly related to the expression of genes p53 and p21.

Analysis on effects of modified dosage of calcium gluconate on patients with hydrofluoric acid burns not in hands or feet / 中华烧伤杂志

Objective@#To retrospectively explore the effects of modified dosage of calcium gluconate (CG) on the patients with hydrofluoric acid burns not in hands or feet.@*Methods@#One hundred and sixty patients with hydrofluoric acid burns not in hands or feet were hospitalized in our burn ward from January 2004 to December 2017. Based on the dosage of CG at different admission time, 76 patients hospitalized from January 2004 to December 2012 were included in traditional group, and 84 patients hospitalized from January 2013 to December 2017 were included in modified group. For patients in the two groups, subcutaneous injection of CG solution at one time was immediately conducted on admission in topical treatment. In traditional group, the injection was CG solution with mass concentration of 100 g/L. For wounds of superficial partial-thickness and above degree, CG solution was prescribed at the dosage of 50 mg/cm2. Wounds of superficial-thickness or mass fraction of hydrofluoric acid less than 20.0% did not receive injection. In modified group, the mass concentration of CG solution for injection was diluted with normal saline to 25 g/L. For wounds of deep partial-thickness and above degree, CG solution was prescribed at the dosage of (50×mass fraction of hydrofluoric acid) mg/cm2. For wounds of superficial partial-thickness, CG solution was prescribed at the dosage of (25×mass fraction of hydrofluoric acid) mg/cm2. For wounds of superficial-thickness, CG solution was prescribed at the dosage of 2.5 mg/cm2. For systemic treatment, the injection velocity of CG solution via venous access was adjusted according to the level of serum calcium namely total serum calcium of patients in traditional group. In modified group, serum ionized calcium was additionally detected through automatic blood gas analyzer by the bed to regulate the injection velocity of CG via venous access. The incidence rate of hypercalcemia and mortality of patients after treatment in the two groups, and the situation about treatment of survivors in the two groups were analyzed. Data were processed with chi-square test, Fisher′s exact probability test, t test, and Mann-Whitney U test.@*Results@#(1) After treatment, 9 patients (11.8%) had hypercalcemia, while the other 67 patients (88.2%) did not have hypercalcemia in traditional group. Two patients (2.4%) had hypercalcemia, while the other 82 patients (97.6%) did not have hypercalcemia in modified group. The incidence rate of hypercalcemia of patients in traditional group was significantly higher than that in modified group (χ2=5.579, P=0.02). (2) There were two deaths (2.6%) and 74 survivors (97.4%) in traditional group, while there were two deaths (2.4%) and 82 survivors (97.6%) in modified group. The mortalities of patients in the two groups were close (P>0.05). (3) The ratios of eschar excision and skin grafting and hyperplastic scar formation, wound healing time, and ratio of esophageal scar stenosis of survivors in the two groups were close (χ2=0.002, 0.054, Z=0.66, P>0.05).@*Conclusions@#Hydrofluoric acid is highly dangerous. The early management of patients with hydrofluoric acid burns emphasizing specialized dosage of CG for treatment can be helpful to reduce incidence of complications and improve the safety of treatment.

Analysis on clinical characteristics of 316 patients with hydrofluoric acid burns / 中华烧伤杂志

Objective@#To investigate the clinical characteristics of patients with hydrofluoric acid (HF) burns.@*Methods@#Clinical data of 316 patients with HF burns admitted to Zhejiang Quhua Hospital from January 2004 to December 2016 were retrospectively analyzed. Patients were divided into non and mild poisoning group (NMP, n=157), moderate poisoning group (MP, n=120), and severe and fatal poisoning group (SFP, n=39) based on the severity of poisoning. Occurrences of hypocalcemia, hypomagnesemia, hypokalemia, and hyperkalemia of patients within 24 hours after admission were recorded. Values of emergency urinary fluoride of patients on admission were recorded. Values of urinary fluoride of patients admitted to hospital in 4 hours post injury in groups MP and SFP at post injury hour 4, 12, and 24 and on post injury day 2, 3, 4, 5, 6, and 7 were also recorded. Electrocardiographic abnormalities of patients within 24 hours after admission were recorded. Data were processed with chi-square test, Kruskal-Wallis H test, and Mann-Whitney U test.@*Results@#(1) Hypocalcemia, hypomagnesemia, and hypokalemia occurred in some patients in each of the three groups, but no patient had hyperkalemia. Taking serum calcium namely total serum calcium as reference, the incidence rate of hypocalcemia of patients in group NMP was close to that in group MP (χ2=0.05, P>0.05). The incidence rate of hypocalcemia of patients in group SFP was significantly higher than that in group NMP or group MP (χ2=10.53, 7.92, P<0.01). The incidence rates of hypokalemia in the three groups were close (χ2=0.63, P>0.05). Taking serum ionized calcium as reference, the incidence ratio of hypocalcemia of patients in group NMP was close to that in group MP (χ2=0.01, P>0.05), while there were statistically significant differences in incidence ratio of hypocalcemia of patients between group SFP and each of group NMP and group MP (χ2=4.66, 4.47, P<0.05). Taking serum calcium as reference, the incidence rate of hypocalcemia of patients was 7.3% (23/316). Taking serum ionized calcium as reference, the incidence rate of hypocalcemia of patients was 60.0% (42/70), which was significantly higher than that of taking serum calcium as reference (χ2=113.74, P<0.01). The incidence rates of hypomagnesemia of patients in groups MP and NMP were close (χ2=0.02, P>0.05). The incidence rate of hypomagnesemia of patients in group SFP was significantly higher than that in group NMP or group MP (χ2=14.69, 9.94, P<0.01). (2) The urinary fluoride levels were tested in 288 patients, with the value of emergency urinary fluoride of patients on admission 0.2-590.0 mg/L. The values of urinary fluoride of 202 patients were above the normal value. The values of emergency urinary fluoride of patients in groups NMP, MP, and SFP were 2.15 (1.11, 4.30), 5.89 (1.72, 14.25), and 36.0 (13.2, 103.2) mg/L, respectively. The values of emergency urinary fluoride of patients in groups MP and SFP were significantly higher than the value in group NMP (χ2=23.28, 66.03, P<0.01). The value of emergency urinary fluoride of patients in group SFP was significantly higher than that in group MP (χ2=39.23, P<0.01). The value of urinary fluoride of 33 patients admitted to hospital within 4 hours post injury in groups MP and SFP reached the top at 4 hours post injury and then gradually declined, which returned to normal on about 5 days post injury. The values of urinary fluoride of patients in group SFP at 4, 12, and 24 hours post injury and on 2, 3, 4, 5, 6, and 7 days post injury were significantly higher than those in group MP (Z=-4.28, -4.15, -3.81, -4.21, -2.48, -2.06, -2.31, -2.68, -3.03, P<0.05 or P<0.01). (3) Twenty-seven patients had electrocardiographic abnormality. There were 12 patients with T wave changes (the most common), 8 patients with ST-T changes, 6 patients with ventricular arrhythmias, 6 patients with conduction block, and 1 patient with broadened QRS waveform. There was no patient with prolonged Q-T interval. The ratios of patients with the above electrocardiographic abnormalities in group SFP were higher than those in group NMP and group MP.@*Conclusions@#Clinical manifestations of patients with HF burn are hypocalcemia, hypomagnesemia, hypokalemia, and electrocardiographic abnormality. In addition to routine serum electrolyte and electrocardiogram monitoring, the levels of serum ionized calcium and urinary fluoride can be helpful to evaluate the severity of illness of the patients.

Effects of fluoride on proliferation and apoptosis of immune cells in rats / 中华地方病学杂志

Objective To study the effects of different fluoride concentrations on proliferation and apoptosis of rats' immune cells,and to explore the effects of fluoride on immune function.Methods Sixty male Wistar rats were randomly divided into four groups,and the concentrations of NaF in drinking water for each group (15 rats in each group) were 0,50,100,and 150 mg/L,respectively.They were freely fed water and commercial standard chow.All rats were sacrificed after 12 weeks.Thymus index was calculated.Lymphocyte proliferation activity in the blood was detected by Cell Counting Kit-8 assay.The apoptosis of monocytes in blood was detected by Annexin V/PI method.The apoptosis of lymphocytes in spleen and thymus was detected by Tunal method.Results After 12 weeks of fluoride exposure,the difference in the thymus immune organ index between the four dose groups was statistically significant (F =6.50,P ＜ 0.05);after 12 weeks,the thymus immune organ index of the low and middle dose groups was significantly lower than that of the control group (0.70 ± 0.19,0.84 ± 0.18 vs 1.16 ± 0.33,P ＜ 0.05).There were significant differences in B and T lymphocyte viability between the four dose groups (F =539.97,4.92,P ＜ 0.05).The viability of B lymphocyte in the blood of the middle dose group was significantly lower than those of control group and the low dose group [(58.09 ± 4.59)％ vs (100.00 ± 9.01)％,(106.70 ± 4.82)％,P ＜ 0.05].The viabilities of T lymphocyte in the blood of the low and middle dose groups were significantly lower than that of the control group [(81.11 ± 2.93)％,(75.68 ± 2.34)％ vs (100.00 ± 34.02)％,P ＜ 0.05].The apoptosis rates of blood mononuclear cells in the fluoride-treated groups were significantly increased than that of control group [(48.00 ± 7.45)％,(47.26± 5.94)％,(48.20 ± 3.40)％ vs (32.50 ± 13.70)％,P ＜ 0.05).Immunohistochemistry results showed that the number of apoptotic lymphocytes in the spleen and thymus increased significantly in high dose group.Conclusion Fluoride can reduce the thymus immune organ index of rats,affect the proliferation of lymphocytes in blood,thymus and spleen,and promote apoptosis of lymphocytes,thus affecting the immune function.

The effects of comprehensive treatment of coal-burning-borne fluorosis areas in Guizhou Province on improving rural environmental hygiene / 中华地方病学杂志

Guizhou had the most serious coal-burning-borne fluorosis areas and was the first implemented province-wide comprehensive control measures in 2010.Through sustainable comprehensive prevention and control measures,the utilization rate of household coal resources in the disease affected areas had been effectively reduced.We improved the structure of domestic energy sources,made significant progress in energy conservation and emission reduction,and significantly improved air pollution.The concept of health and hygiene had been deeply rooted in the hearts of the people.The transformation of citizens' knowledge,trust and conduct gradually took shape,and the comprehensive prevention and control measures achieved remarkable results.

Surveillance on drinking water-borne endemic fluorosis in Shandong Province from 2013 to 2017 / 中华地方病学杂志

Objective To understand the implementation effects of control measures and the dynamic prevalence of drinking water-borne endemic fluorosis in Shandong Province.Methods From 2013 to 2017 in Shandong Province drinking water-borne endemic fluorosis areas,in accordance with the method of simple random sampling,10 monitored counties were selected,10 water fluorine decreasing projects were investigated of its running effect,and water fluoride was detected.In each monitored county,3 villages in the diseased areas were selected as fixed monitored villages.If the monitored village had changed its water,the operation of the project would be investigated.If the monitored village had not changed the water,one water sample would be collected according to 5 directions of east,west,south,north and middle to determine the water fluorine.All children aged from 8 to 12 in the village were also examined for dental fluorosis.X-ray fluorosis and urinary fluorosis in adults aged over 25 were detected in 2013 and 2017.Results From 2013 to 2017,in monitored counties,the normal operation rate of improved-water defluoridation projects was 99.19％ (368/371),the qualified rate of water fluoride content was 66.85％ (248/371).In 128 improved water projects,the normal operation rate was 100.00％ (128/128),the qualified rate of water fluoride content was 67.19％ (86/128).The average detection rate of dental fluorosis and community fluorosis index (CFI) in children aged 8-12 were 33.92％ (2 608/7 689) and 0.68 in all monitored counties from 2013 to 2017.The detection rate presented a declining trend year by year (x2 =152.47 P ＜ 0.01).The average detection rate and CFI in the villages with normal operation projects and qualified fluoride content were 26.10％ (1 311/5 023) and 0.47.The detection rate presented a declining trend year by year (x2 =207.67 P ＜ 0.01).The detection rate and CFI in the villages with water improvement projects under abnormal operation or excessive fluoride were 48.65％ (1 297/2 666) and 0.90.The detection rate of dental fluorosis in the villages with normal operation projects and qualified fluoride content was lower than the rate of the villages with water improvement projects under abnormal operation or excessive fluoride (x2 =193.98,P ＜ 0.01).In 2013 and 2017,X-ray detection rates of skeletal fluorosis in adults aged over 25 were 8.04％ (119/1 481) and 6.04％ (81/1 342),respectively.The adult urinary fluoride geometric mean values (1.24,1.49 mg/L) were lower than the normal limit of 1.6 mg/L both in qualified villages of water ffuoride content and exceeding-standard villages in 2017.Conclusions In Shandong Province,the effective water improvement has acquired some effects in control of drinking water-borne endemic fluorosis.But the water fluoride content of improved water defluoridation projects exceeds the national standard seriously and fluorosis has not been effectively controlled.

An evaluation of the effectiveness of prevention and control measures on coal-burning-borne endemic fluorosis in Shanxi Province / 中华地方病学杂志

Objective To evaluate the effects of prevention and control measures on coal-burning-borne endemic fluorosis in Shanxi Province, and to provide a scientific basis for further prevention and treatment of the disease. Methods In 2016, 7 diseased counties (cities) were selected in the whole province, three diseased townships were selected in each county(city), and five diseased villages were selected in each diseased township as the investigation sites. The investigation was carried out on the changes of improved stove and correct usage of the improved stove, and the correct drying behavior related to the corn and pepper for human consumption. Children aged 8 to 12 were examined dental fluorosis. In each village, 20 urine samples of 8 to 12 years old children were collected for fluorine determination. Urine fluoride was determined via the fluoride ion selective electrode method, and children dental fluorosis was diagnosed by "Diagnosis of Dental Fluorosis" method (WS/T 208-2011). Results Altogether 105 villages were investigated, including 31 696 households. The rates of the improved stove and the correct usage of the improved stove were 98.46%(31 209/31 696)and 98.80%(30 834/31 209);the correct drying rate related to the corn and pepper for human consumption was 99.97%(31 685/31 696);the dental fluorosis rate of 8 to 12 years old children,and the dental fluorosis index were 5.56%(264/4 751) and 0.13. The urine fluoride content was between 0.15 - 4.33 mg/L and the geometric mean value of fluoride content was 0.72 mg/L. Conclusions The prevention and control effect is obvious on coal-burning-borne endemic fluorosis in Shanxi Province. Disease surveillance,health education,the management and maintenance work of defluoridation stoves are keys in prevention of coal-burning-borne endemic fluorosis.

Unhas das mãos como biomarcador para fluorose dentária / Fingernails as a biomarker for dental fluorosis

INTRODUCTION: Biomarkers indicate levels of a particular chemical agent in the environment studied, which may be useful for monitoring health status, and nails may be major indicators of fluoride. OBJECTIVE: To evaluate fluoride concentration in the fingernails of children as a biomarker for fluoride exposure. METHODS: Twenty students were selected, aged 4-5 years old. Their nails were cut at 15 and 45 days (two collections), and the fluoride concentration in the nails was analyzed with the ion-specific electrode (Orion 9409) after rapid diffusion with HDMS. RESULTS: The total fluoride mean of the samples was 3.68 μg F/g (sd 1.44), ranging from 1.39 μg F/g to 7.81 μg F/g. Eleven children (55%) brush their teeth three times a day, but only three children (15%) swallow toothpaste. CONCLUSION: There is a high prevalence of fluoride exposure in the fingernails of the children studied, presenting risk of developing dental fluorosis in permanent teeth.

INTRODUÇÃO: Os biomarcadores indicam níveis de determinado agente químico no meio estudado, os quais podem ser úteis ao monitoramento do estado de saúde, podendo as unhas serem importantes indicadores de flúor. OBJETIVO: Avaliar a concentração de flúor nas unhas das mãos de crianças como biomarcador de exposição ao flúo.r MÉTODO: Foram selecionadas 20 escolares, com idade entre 4 e 5 anos. As unhas foram cortadas aos 15 e 45 dias (duas coletas) e a concentração de flúor nas unhas foi analisada com o eletrodo íon específica (Orion 9409), após difusão facilitada por HDMS RESULTADOS: A média total de flúor das amostras foi de 3,68 µg F/g (dp 1,44), variando de 1,39 µg F/g a 7,81 µg F/g. Onze crianças (55%) escovam os dentes três vezes por dia, porém, somente três crianças (15%), engolem dentifrício. CONCLUSÃO: Há uma alta prevalência de exposição ao flúor nas unhas das mãos das crianças investigada com risco de desenvolver fluorose dentária nos dentes permanentes.

Fluoretação da água de abastecimento público: abordagem bioética, legal e política / Fluoridation of public water supply: bioethical, legal and political approach / La fluoración del agua de abastecimiento público: abordaje bioético, legal y político

Resumo Este artigo tem como objetivo analisar aspectos bioéticos e questões legais e políticas da fluoretação de águas de abastecimento público, criando discussões baseadas em estudos consagrados e em novas pesquisas, a fim de contribuir para abordagem imparcial do tema. Trata-se de revisão bibliográfica realizada após levantamento de literatura especializada sobre "fluoretação", "bioética" e "intoxicação por flúor". Foram selecionados estudos que possibilitaram discussão plural, relevantes para o debate do tema. A fluoretação das águas de abastecimento público é importante medida de saúde pública para prevenir a cárie dentária, tendo sua eficácia comprovada em vários estudos. Sua obrigatoriedade prevista por lei federal gera dilemas bioéticos, pois exclui a possibilidade de escolha individual de consumir ou não água fluoretada. Não parece haver saída para esse dilema moral, mesmo se a medida fosse livre de qualquer risco, pois ainda assim violaria o princípio da autonomia.

Abstract This article aims to analyze the bioethical aspects and legal and political issues of water fluoridation, creating a discussion based on established studies and new research, in order to contribute to an ethical and impartial perspective on the subject. A bibliographic review study was performed, based on a survey of specialized literature on "fluoridation", "bioethics" and "fluoride poisoning". Water fluoridation is an important public health measure for the prevention of dental caries, and its efficacy has been demonstrated in several studies. As it is mandatory under Brazilian law, bioethical dilemmas arise due to the absence of individual choice on whether to consume or not consume fluoridated water. There appears to be no solution to this moral dilemma, as even if the measure were free from any risk, its compulsory application would still violate the principle of autonomy.

Resumen El objetivo de este artículo es analizar los aspectos bioéticos y asuntos legales y políticos de la fluoración del agua de abastecimiento público, al crear discusiones en base a estudios consagrados y a nuevas investigaciones, con el fin de contribuir con un enfoque imparcial del tema. Se trata de la revisión bibliográfica realizada después de estudiar la literatura especializada sobre la "fluoración", "bioética" e " intoxicación por flúor". Se seleccionaron los estudios que permitieron la discusión plural, lo cual fue relevante para el debate del tema. La fluoración de agua de abastecimiento público es una medida de salud pública importante para prevenir la caries dental y su efectividad se comprobó en varios estudios. Su obligatoriedad prevista por la Ley Federal genera dilemas bioéticos, ya que elimina la posibilidad de la elección individual de consumir o no el agua fluorada. No parece haber una salida para este dilema moral, incluso si la medida estuviese libre de cualquier riesgo, ya que aun así estaría violando el principio de autonomía.

Quantitative computed tomography measurement skeletal fluorosis rabbits bone density and the correlation with bone injury / 中华地方病学杂志

Objective To detect the early diversification of the bone mineral density in skeletal fluorosis of rabbits by quantitative computed tomography (QCT),and analyze the possible relationship between bone mineral density and bone injury in rabbits with fluorosis.Methods A total of 16 rabbits,half male and half female,were randomly divided into control and experimental groups according to body weight.The two groups of rabbits were given drinking water containing NaF 0 or 300 mg/L,respectively,for 90 days.After the experiment,their bone fluoride content was determined via the fluorine ion-selective electrode method.The alkaline phosphatase (ALP) and osteocalcin (BGP) in serum were measured using enzyme-linked immunosorbent assay (ELISA).Femurl bone mineral density was detected with QCT in vivo.Histopathological changes of femur were observed under light microscope and trabecular acreage was calculated.The results were analyzed with independent-samples t test(t') and partial correlations.Results The bone fluoride content [(3 232.16 ± 927.85) mg/kg],ALP [(42.69 ± 3.28) U/L],BGP concentration [(2 504.19 ± 276.79) μg/L],bone density [(653.49 ± 167.81) g/cm3] and trabecular number [(39.02 ± 3.33)Tb.Ar] of the experimental group were higher than those of control group [(554.01 ± 376.51)mg/kg,(20.50 ± 4.90)U/L,(1 294.60 ± 191.86)μg/L,(540.40 ± 41.99)g/cm3,(8.15 ± 2.34)Tb.Ar],and the differences were statistically significant (t'=7.565,10.641,10.158,2.615,14.494,all P ＜ 0.05).The tissue sclerosis,bone sclerosis and bone texture coarsening were observed through bone mineral density imaging taken by QCT in experimental group.The number of trabeculae increased and the arrangement of tra bec ulae was disorganized.Bone mineral density was positively correlated with bone fluoride,trabeculae,BGP and ALP (r =0.702,0.627,0.614,0.567,all P ＜ 0.05).Conclusions QCT bone density measurement in skeletal fluorosis of rabbits can be used to compute the threedimensional bone density.And it has a good correlation with bone fluoride content,bone histopathological changes and index of bone metabolism in skeletal fluorosis,which suggests that QCT may provide a useful reference for application in patients with skeletal fluorosis.