Jentsch HFR, et al. - This randomized clinical trial was undertaken to determine whether professional oral prophylaxis prior to scaling and root planing (SRP) has an impact on the outcome of non-surgical periodontal treatment in chronic periodontitis patients. Fifty-two people with chronic periodontitis receiving nonsurgical periodontal therapy by SRP with (test) and without (control) two professional tooth cleaning appointments but with motivation and instruction were supervised for clinical factors, four chosen microorganisms and two biomarkers at baseline, before SRP as well as 3 and 6 months after SRP. According to findings, 3 and 6 months after SRP, PD, AL, BOP and interproximal plaque index (API) enhanced significantly in both groups. At the appointment immediately before SRP, PD, BOP, API and the number of sites with PD ≥ 5 mm were significantly lower in the test group than in the control group. The authors discovered that pre-SRP professional tooth cleaning does not enhance the SRP's clinical outcomes. It has no apparent long-lasting impacts in the subgingival biofilm on significant periodontopathogens as well as on biomarkers in the post-SRP gingival crevicular fluid.