Additionally, in our previous research, we have observed that scaling and root planing (SRP) in patients with chronic periodontitis led to a significant decrease in MMP-8 concentration in GCF [45] and that the level of this factor in PISF received from the patients without any signs of peri-implantitis was notably higher than in GCF of periodontally healthy patients [16]. This evidence concerns the gene MMP8 and chronic periodontitis.