While there is some lack of agreement as to what constitutes the optimal technique and procedural time and interval for each patient, scaling and root planing (SRP) is considered to be the gold standard for non-surgical periodontal therapies. Cobb reviewed numerous non-controlled clinical trials and case reports and found SRP to be very effective in improving clinical parameters, with pocket depth reductions averaging 2 mm, for chronic periodontitis patients.13 Properly controlled, blinded, and powered clinical trials generally show a mean probing pocket depth (PPD) reduction of approximately 1 mm with SRP therapy alone.14,15,16 It is interesting that case reports and consecutive case studies summarized in the 1996 World Workshop generally show a mean PPD reduction of approximately 1.5 to 2 mm, which is nearly 1 mm greater, or almost 100% greater, than the PPD reduction found in randomized, controlled clinical trials. A breakdown of the groups shows that initially moderately deep sites of 4-6 mm show a mean pocket depth reduction of 1.29 mm; while the initially deep sites of ≥ 7 mm show a mean pocket depth reduction of 2.16 mm. Case study outcomes are generally considered to be less reliably predictive of expected patient outcomes due to the influence of non-controlled confounding variables and the influence of bias. There is still a need for more research to answer questions about the relative benefits of full-mouth disinfection vs. quadrant SRP, shorter vs. longer procedural time per tooth, etc.