Reddy, V VIndushekar, K R1992-03-012009-06-021992-03-012009-06-021992-03-01Reddy VV, Indushekar KR. In vitro evaluation of NaF and APF-gel application on surface microhardness of enamel in children of low, optimum and high fluoride areas. Journal of the Indian Society of Pedodontics and Preventive Dentistry. 1992 Mar; 10(1): 1-6http://imsear.searo.who.int/handle/123456789/114750An in vitro study was conducted on 78 sound human pre-molars collected from low (0.24 ppmF), optimum (0.7 ppmF) and known endemic fluoride areas (> 1.5 ppmF), to study the effects of topical application of sodium fluoride and APF-gel on surface microhardness of enamel of these three areas using Vickers microhardness measurements before and after application of topical fluorides at time intervals of 1/2 an hour, 6 hours and 24 hours. It was found that both the topical fluorides increased the surface microhardness of enamel in the three areas; the maximum increase in surface microhardness was observed in fluorosed teeth. APF-gel was found to be more effective than sodium fluoride.engAcidulated Phosphate Fluoride --pharmacologyChildDental Enamel --drug effectsFluoridation --adverse effectsFluorosis, Dental --drug therapyGelsHardnessHardness TestsHumansSodium Fluoride --pharmacologySurface PropertiesTime FactorsComparative Study