The most cities which their inhabitants are 
suffering from fluorosis, located in plain regions or 
margins of seas. However; there are some other cities 
located in high and mountainous regions with high 
prevalence of the fluorosis. Fluoride is not entered to the 
body only through drinking water, but it could also enter 
through food products especially teas and sea foods. The 
high level of fluoride in some food products, in a region, 
may be due to the high level of fluoride in drinking or 
agricultural waters and soil of the region or both. 
Excessive amount of fluoride in air may also cause 
fluorosis and this is especially true for cities that are 
located near Volcanoes, coal mine or Aluminum factory. 
Studies have shown in cities that are located in high 
regions and fluoride in drinking and agriculture waters is 
higher than normal range, severity of fluorosis is more 
than cities with the same level of fluoride in waters but 
located in lower-high areas. It seems living in high regions 
is caused relative hypoxia in the tissues as a result of 
decreased oxygen pressure; therefore there would be more 
fluoride retention in the tissues. The studies have shown in 
areas with high fluoride in waters and/or food products, 
the fluorosis is more prevalent in the rural regions than neighbor urban regions. It seems malnutrition and 
nutritional deficiencies are more prevalent in rural regions 
than urban regions. In the tooth formation process, 
nutritional deficiencies (particularly proteins, vitamins A, 
B deficiencies) are result in a weak enamel matrix which 
is more touched by high levels of fluoride consumed. In 
these cases, the final result is dental fluorosis with high 
severity. 

Keywords: Fluoride; Fluorosis; Drinking Water