Objectives: The objective of this paper is to show the importance of the detection of periodontopathogenic bacteria using different methods from the oral swab samples in patients with periodontitis for the purpose of applying therapy in their treatment. Material and methods: The material used for analysis is subgingival plaque. The detection of bacteria is done using different methods: bacterial culture cultivation, commercially available kits and Real-time PCR. Results: The results of the bacterial culture are reported in the form of CFU/ml and the results of the commercial kit show a qualitative result from 0 to +++. With real-time PCR, in addition to a qualitative result, a semi-quantitative result can also be obtained. Conclusion: Detection of periodontopathogenic bacteria in patients with periodontitis is important to determine the correct therapy. We determine the presence of bacteria by culturing a bacterial culture from a subgingival sample, but this is a slow method, so today commercial kits or Real-time PCR methods are used more and more, with which we get results much faster and more precisely, and thus the patient gets the therapy sooner.