This is a prospective randomized double blind clinical controlled trial (RCT). Fifty-two systemically healthy adult patients (19 females and 33 males) ranging in age from 35 to 70 years of age, with moderate to advanced chronic periodontitis with at least 1 infrabony defect being >3mm in depth were included. Patients were recruited and treated at the Department of Periodontology dental clinic from the Universitat Internacional de Catalunya, Barcelona, Spain. The sample size calculation was based on a previous pilot study in 10 patients in which differences in between groups where set at 1mm in CAL gain as the primary outcome, with an alpha error of 0.05 and a beta error of 0.9. Thus, the sample size was established for 52 patients including dropouts. The Ethics Committee at the International University of Catalonia (UIC) approved the study design with the code PER-ECL-2011-04-CM. This RCT is registered and follows the CONSORT guidelines as well as the Helsinki declaration for human research. Prior to the initiation of this study, an informed consent was obtained from each patient after explaining the nature of the investigation.