The occlusal trauma has been defined as an injury to the periodontium resulting from occlusal forces that exceeds the reparative capacity of the attachment apparatus. Currently, the effects of occlusal trauma on tooth support tissues, the onset and the progression of periodontal disease are still debated. In fact, researchers started evaluating the possible effects of occlusal discrepancies on incidence, progression, and treatment outcomes of periodontitis, but all the results underlined the more significant role played by microbiological flora. The results of this study show that after 60 days of treating the occlusal trauma, a significant reduction was achieved in the periodontal bacterial flora.