Goals: Evaluate the root cause of periodontal disease, the predominance of bacteria and the total bacterial load before and after.

Materials and Methods: Microbiological Tests: it consists in taking the crevicular fluid colonized by bacteria and containing epithelial cells of the person being examined, using a sterile paper cone with a diameter of 60/80 in the periodontal or peri-implant pocket for at least 30 seconds (so that it is soaked in liquid crevicular possibly without blood); it is placed inside the test tube; the procedure is repeated to obtain from a minimum of two to a maximum of four paper cones. The test was performed on 420 patients aged 30-60 years, 236 women, 184 men, 4-11mm pockets moderatesevere chronic periodontitis, for a total of 498 samples, in 78 patients a second sampling was carried out after treatment.

Results: The study highlighted that the main cause of periodontal disease are parafunctions (Bruxism, clenching, bad habits, atypical swallowing,mouth breathing), dental misalignment, pre-contacts and incongruous prosthetic products.