The current study was conducted to compare the efficacy of three fluoride-containing varnishes (CPP-ACP, TCP and NaF) regarding their ability to remineralize initial enamel lesions of permanent and primary teeth and their ability to occlude the dentinal tubules of permanent teeth.Permanent enamel samples used for this study were created from human premolars extracted due to orthodontic reasons and stored in 0.1% thymol solution till further used. The premolars were cut longitudinally in mesio-distal direction then polished. The samples were divided equally (n=15) into three study groups: Group 1: received CPP-ACP containing fluoride varnish Group 2: received TCP containing fluoride varnish Group 3: received NaF containing fluoride varnishThe primary enamel samples were created from human decidous molars extracted due to clinical mobility near their exfoliation time and stored in 0.1% thymol solution till further used. The molars were cut longitudinally in mesio-distal direction then polished. The samples were divided equally (n=15) into three study groups: Group 1: received CPP-ACP containing fluoride varnish Group 2: received TCP containing fluoride varnish Group 3: received NaF containing fluoride varnishDentin Samples used for assessment of dentinal tubules occlusion were created from human premolars extracted due to orthodontic reasons and stored in 0.1% thymol solution till further used. The premolars were cut at the cementoenamel junction level at a transverse direction then polished.