Authors searched into 316 18-years old students with aim to detect primary approximal caries on molars and premolars using radiographic examination. They examined everyone, after their filling the preliminary questionnaire, by a clinical examination of teeth and periodontal tissue, made two radiographs (bitewing) and performed their reading. Total number of approximal surfaces on bitewings was 9782, from these 2611 (26.7%) surfaces were not possible to read, 407 (4.2%) were treated by a filling. Remaining 6764 (69.1%) untreated surfaces were evaluated by caries depth throw enamel and dentin using the grading from methods. 62% of approximal surfaces were without caries damage - D0, D1 – 10%, D2 – 10%, D3 – 7%a D4 – 6%of approximal surfaces. Authors particularised rate of individual distal teeth and found out that distal and mesial approximal surfaces of the second upper and lower molar had the least caries occurrence but mesial approximal surfaces of the first upper molar and distal approximal surfaces of the first lower molar had the most caries occurrence. They had to establish the absence of interdental hygiene by 82% of examinants.

        Key words: approximal caries – approximal caries detection – bitewing – interdental hygiene