Foreword: Kinane, D.F.; Mombelli, A.; Subgingival Biofilm Structure: Zijnge, V.; Ammann, T.; Thurnheer, T.; Gmur, R.; Microbial Diversity and Interactions in Subgingival Biofilm Communities: Diaz, P.I.; Innate Cellular Responses to the Periodontal Biofilm: Benakanakere, M.; Kinane, D.F.; Neutrophils in Periodontal Inflammation: Scott, D.A.; Krauss, J.L.; Antimicrobial Peptides in Periodontal Innate Defense: Gorr, S.-U.; Modern Approaches to Non-Surgical Biofilm Management: Apatzidou, D.A.; Animal Models to Study Host-Bacteria Interactions Involved in Periodontitis: Graves, D.T.; Kang, J.; Andriankaja, O.; Wada, K.; Rossa, C., Jr.; Antimicrobial Advances in Treating Periodontal Diseases: Mombelli, A.; Regenerative Periodontal Therapy: Kao, D.W.K.; Fiorellini, J.P.; Paradigm Shift in the Pharmacological Management of Periodontal Diseases: Hasturk, H.; Kantarci, A.; Van Dyke, T.E.