Among the following varnish Which of the following has flouride concentration less than duraphat but having equivalent efficacy:
Duraflour
Carex
Flour protector.
None of the above.
Flouride varnish was first developed in Europe by Schimdt. They maintain the fluoride ions in intimate contact with enamel for longer periods. The two commonly used varnishes are –

Duraphat: It is the first flouride varnish and contains 22600 ppm fluoride as NaF in a neutral colophonium base (NaF varnish containing 2.26% fluoride in organic lacquer)
Fluor Protector (Fluoride concentration is about 7000 ppm or 0.70%)
Carex: Contains a lower fluoride concentration than Duraphat--(1.8%  fluoride) and has efficacy equivalent to that of Duraphat.
Duraflour - 22.6 mg/ml.

Contains NaF in alcoholic suspension of natural resins with xylitol as sweetening agent.

Cavity shield: 5% NaF in resinous base.