[Characteristics, diagnosis and treatment of the most common bacterial diseases of the oral cavity].

Billions of microorganisms can be found in the oral cavity, from which bacteria are the most frequent. More than 600 bacterial species can be isolated. Most of them are harmless, moreover, some species prove themselves to be specifically useful. However, in the case of a weakened immune status or inappropriate oral hygiene, they may cause many types of soft and hard tissue disorders. Caries and periodontal diseases are the most common bacterial diseases of the oral cavity. In both cases, the dental biofilm gives rise to the disorder, which is caused by the insufficient oral hygiene. Dental caries are mainly caused by cariogenic streptococci and lactobacilli. In the case of serious periodontal diseases, anaerob parodonto-pathogen microorganisms play the major role. Untreated caries may result in the necrosis of the pulp, which can cause an inflammation expanding towards the parodontium. This can be characterized as a focal infection, like the untreated periodontal pockets. Dental foci may have lots of systemic consequences such as cardiovascular diseases, diabetes, pneumonia, arthritis, preterm birth and alopecia areata. When these diseases occur, dental foci should always be considered. The professional plaque control and chlorhexidine rinsing before the proposed surgeries have an outstanding role in the prevention of ventilator-associated pneumonia. Oral cancer is multicausal; more and more researchers are analyzing the role of certain bacteria in the carcinogenesis of oral cancer. In addition to the mentioned clinical aspects, we are planning to describe the relatively rare, but diverse and diagnostically challenging bacterial soft tissue disorders in another publication. Orv Hetil. 2019; 160(19): 739-746.