A) 1ppm
B) 3ppm
C) 5ppm
D) 10ppm
Correct Answer: D
Solution :
Flupride's tolerable limit is 1 ppm?\[\left( Imgd{{m}^{-3}} \right)\]. It protects teeth against decay, but above 2ppm causes brown mottling of teeth. And more than 10 ppm are harmful to bones and teeth. The F~ ions make the enamel on the teeth much harder by converting hydroxyapatite, on surface of teeth into much harder fluloraptite.You need to login to perform this action.
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