Jentsch HFR, et al. - In patients with chronic periodontitis, researchers explored whether the result of non-surgical periodontal therapy is affected by professional oral prophylaxis before scaling and root planing (SRP). For this investigation, 52 people with chronic periodontitis receiving non-surgical periodontal therapy by SRP with (test) and without (control) two professional tooth cleaning appointments but with motivation and instruction were monitored for clinical variables, four chosen microorganisms and two biomarkers at baseline, prior to SRP as well as 3 and 6 months after SRP. In both groups 3 and 6 months after SRP, probing depth, attachment level, bleeding on probing, and interproximal plaque index improved significantly Tannerella forsythia was significantly decreased in both groups at 3 and 6 months, Porphyromonas gingivalis only in the test group. Interleukin-1β decreased significantly in control group 3 and 6 months after SRP, the level of matrix metalloproteinase-8 decreased 3 months after SRP in the test group. Before the SRP, professional tooth cleaning does not enhance the SRP's clinical outcomes. It has no obvious long-lasting impacts in the subgingival biofilm on major periodontopathogens as well as on biomarkers in the gingival crevicular fluid after SRP.