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What is Active fluoride concentration in the cavity varnish duraphat is: and explain in detail?
Duraphat, the first fluoride varnish developed in Germany.
	It is a viscous yellowish material, containing 22,600 ppm fluoride as sodium fluoride in a neutral colophonium base (NaF varnish containing 2.26% fluoride in organic lacquer). 
Duraphat has shown caries reduction between 30% and 40% in the permanent dentition and in between 7% and 44% in the primary dentition.

Essentials of preventive and community dentistry
Soben Peter
5th edition
page no. 255