To provide a basis for development of preventive measures through dynamical monitoring of the changing trends of endemic fluorosis areas and the prevalence of drinking-water-borne endemic fluorosis.

Using simple random sampling method, thirty monitoring villages in 11 counties of Inner Mongolia were selected as fixed monitoring villages from 2012 to 2016. The operation of water improvement projects was investigated, and water fluoride content was tested. Dental fluorosis of all 8 to 12-year-old students was diagnosed in the villages. Stratified random sampling by age was used to select 50 adults over 25-year-old in each monitoring village, and skeletal fluorosis was examined by X-ray.

①In 2012-2016, the water-improved rate of monitoring villages was 78.67% (118/150). Of all the water-improved projects, normal operating projects accounted for 92.98% (106/114). The exceeded rate of water fluoride in water-improved village was 31.36% (37/118). ②The detection rate of dental fluorosis and community fluorosis index (CFI) in children aged 8-12 of the villages with normal operating projects and qualified fluoride content were 20.88% (533/2 553) and 0.41; the detection rate of dental fluorosis and CFI of the villages with water-improved projects under abnormal operation or excessive fluoride were 49.53% (318/642) and 0.98; the detection rate of dental fluorosis and CFI of the villages without water-improved projects were 37.14% (442/1 190) and 0.76. ③The detection rate of X-ray skeletal fluorosis in adults of the villages with normal operating projects and qualified fluoride content was 18.97% (140/738); the detection rate of X-ray skeletal fluorosis in adults of the villages with water-improved projects under abnormal operation or excessive fluoride was 31.53% (111/352); the detection rate of X-ray in adults of the villages without water improvement projects was 31.17% (96/308).

Up to now, in Inner Mongolia Autonomous Region, some villages have not yet improved their drinking water quality, water fluoride content in some projects has exceeded the standard seriously, the prevalence of dental fluorosis in children aged 8-12 is very mild, there are still moderate and severe endemic areas. So the prevention and control measures of the water-improved defluoridation need to be further strengthened.

Fluorosis, dental; Skeletal fluorosis; Monitoring