Effect of different water-improving methods on dental fluorosis of children in 50 drinking-water-borne fluorosis areas in Xi'an City / 中华地方病学杂志

ABSTRACT

Objective:To evaluate the effect of different water-improving methods on dental fluorosis of children aged 8 to 12 in drinking-water-borne fluorosis areas in Xi'an City, and provide basis for making fine prevention and control measures.Methods:In 2018, 50 drinking-water-borne fluorosis villages in Xi'an City with water improvement time from 2011 to 2013 were selected as survey sites. The condition and the way of water improvement were surveyed, water fluoride content was determined and the prevalence of dental fluorosis in children aged 8 to 12 was examined, and the rates of dental fluorosis were compared before and after the water improvement in the 50 villages.Results:The water-improving projects were in normal operation in 50 villages. The medians of water fluoride content were 0.31, 0.88 and 1.14 mg/L in villages with municipal water supply, low fluorine well and defluoridation treatment water supply (the villages of different water-improvement methods were 12, 24 and 14, respectively), the differences were statistically significant ( H = 75.54, P < 0.01). The qualification rates of water fluoride in villages with different water-improvement methods were 100.00% (12/12), 79.17% (19/24) and 57.14% (8/14), and the difference was statistically significant (χ 2 = 6.95, P < 0.05). The detection rate of dental fluorosis was 43.17% (218/505) in the 11 villages with excessive water fluoride content, and the detection rate was 20.77% (331/1 594) in the 39 villages with qualified water fluoride content, the difference was statistically significant (χ 2 = 99.66, P < 0.01). After water improvement, the total detection rate of dental fluorosis (26.16%, 549/2 099) in the 50 villages was lower than that before water improvement (41.66%, 959/2 302), the difference was statistically significant (χ 2 = 117.17, P < 0.01). The detection rates of dental fluorosis were reduced after the water improvement in villages with municipal water supply and low fluorine well, the differences were statistically significant (χ 2 = 74.37, 69.36, P < 0.01). The detection rate was declined after water improvement in villages with defluoridation treatment water supply, but the difference was not significant (χ 2 = 0.78, P > 0.05). There was a statistically significant difference in the detection rate of dental fluorosis among children in villages with different water-improvement methods (χ 2 = 72.79, P < 0.01). The detection rate of dental fluorosis in villages with defluoridation treatment water supply [39.53% (200/506)] was higher than that in villages with municipal water supply [17.97% (133/740)] and low fluorine well [25.32% (216/853)], the differences were statistically significant ( P < 0.017); the detection rate of dental fluorosis in villages with municipal water supply was lower than that in villages with low fluorine well ( P < 0.017). Conclusions:The dental fluorosis of children's has been effectively controlled in the villages after water improvement in Xi'an City. The fluoride content in the water and the detection rate of dental fluorosis in children in some endemic areas are still high. It is necessary to further improve the water quality or consolidate the improvement effect as soon as possible.