Epidemiological study of oral health of children aged 5, 12 and 15 years was conducted in 1998. Altogether 435 5-yr-olds, 452 12-yr-olds and 450 15-yr-olds were examined. Dental and periodontal status were recorded and following characteristics were calculated: dmf, DMF teeth, percentage of caries free, percentages of dmf (DMF) components, Restorative index, dental and periodontal treatment need. Data gained in 1998 were compared with those of previous studies in 1993 and 1987. The average value of dmft in 5 -yr-olds amounted to 3.69 and the percentage of caries free amounted to 26.7 %. In 12-yr-olds and 15-yr-olds the DMFT amounted to 3.38 and 4.95 resp. and the percentage of caries free was 13.9 % and 9.8 % resp. When compared the above data with those of previous surveys, following significant changes were observed: caries experience of deciduous dentition increased and percentage of caries free preschool children decreased. In 12-yr-olds a mild increase of caries experience was observed, while 15-yr-olds showed significant decrease of caries experience and improvement of perio- dontal health.

        Key words: oral epidemiology – oral health – 5, 12 and 15 year olds – caries experience – dental status – periodontal status