The aim of the study was to identify, in children suffering from ECC, common ethiological factors which might be eliminated by effective preventive measures. The authors examined 117 children at the age of 15 months to 4 years suffering from ECC and calculated the dmft. CRT bacteria test was used in 30 children to determine the number of microbes – strains of Streptococcus mutans and Lactobacillus in saliva and the findings were statistically evaluated by Fischer’s exact test. Scanning electron microscopy (SEM) was used to evaluate the appearance of the tooth surface in 20 extracted primary 1 teeth. The dmft index ranged from 2–20, high number of microbes was found in saliva, in Streptococcus n>105 was identified in 76.6%,in Lactobacillus in 89.9%.The level of values did not decrease significantly in following investigations (six months and one year later). SEM examination revealed rod microbes, filamentous bacteria, cocci and Candida albicans in the plaque covering the tooth surfaces.The authors formulated 13 preventive measures on the basis of their own findings and experience.

        Key words: ECC – dmft – dental caries – prevention