Fluoride:

Fluoride occurs sometimes naturally in water. If not, it should be added in controlled quantity during treatment process. Fluoridation of water supplies to a level of 1 mg/l is safe and effective in reducing dental caries. The greatest advantage against teeth decay is when water is drunk in childhood during the period of tooth formation. However, optimum concentration of fluoride has to be controlled because excessive amount leads to fluorosis, which causes mottling of the teeth and sometimes bone damage both in children and adults. Ground water passing through chalk or limestone under clay formations may have high concentration of fluoride. Since specialized treatment is to be applied to control higher concentration of fluoride, the treatment becomes quite costly and it is better to go for some other source containing lesser fluoride content.