In this blind randomized study the results of the use of agents for dental caries prevention are presented. The study included 136 children of 7-12 years old, divided into four groups according to the used agent: 3M ESPE Clinpro XT Varnish (n=35), Multifluorid (n=37), Gluftored (n=23) and a control group (n=41) who was given the recommendations on individual oral hygiene with the use of fluoride toothpaste. The groups correlate to gender, age and the risk of dental caries development. Prevention efficacy was determined using the test of enamel resistance (painting of enamel area pretreated with acid). Results: the use of long-acting fluorine varnish 3M ESPE Clinpro XT Varnish statistically significantly increases enamel resistance in comparison with other fluorine agents. The effect of the agent is due to the possibility of long-term exposure to the tooth enamel.