Figure 1: (a) Healthy dentogingival junction is an active part of the innate periodontal defense. (b) The epithelium and connective tissue are affected at the initial phase of periodontal tissue destruction. (c) In periodontitis the epithelial barrier is broken, bacteria may invade the tissue (black spots), and connective tissue and bone are degraded. Junctional epithelium, dark red. Connective tissue and periodontal ligament fibers green, and bone yellow. Bacteria black, pocket epithelium light gray. (a) Is a modified version of a figure from Pöllänen et al. [112].