Dental caries (lat. caries - decay) is a disease present in every population around the world and it is the main reason of pain and loss of teeth. According to the WHO definition, it is a localized, posteruptive pathological process of microbial origin, which demineralizes hard dental tissues with the progression of creating cavity. The development of dental caries is supported by microorganisms located in the biofilm. Numerous factors can be classified as the causes of dental caries, and may have a greater or lesser effect on its development. The main factors are count of bacteria S. mutans and L. acidophilus in saliva, diet, oral hygiene habits, lack of fluorides, prolonged lactation, socioeconomic status, race, gender, age, amount of stimulated saliva, index and metabolic activity of dental plaque. The understanding of caries and its main factors is important for assessing and controlling the risk for its emergence. The dentist is responsible for educating patients and for providing them all necessary information on preventive measures (oral hygiene, diet, fluoride use, preventive fill/seal). The use of ''Cariogram'', an instrument of forecasting the future of dental caries among individuals, also plays an important role in the quantitative assessment of caries risk. It is a model that graphically shows the interaction of factors important for the development of dental caries. Conducted study on the awareness and use of the ''Cariogram'' in the dental medicine practice in Rijeka showed that only 3 out of 75 examined dental clinics use the ''Cariogram'', while 48 of them are informed about the effectiveness of this application and are still not using it. The result of this study indicates the need for educating and stimulating not only patients but also doctors of dental medicine. The best way to achieve this goal are the courses and the financial support of HZZO - the health policy of the Republic of Croatia.