The subject Periodontology considers a broad range of issues that represent contemporary controversies in the discipline. The current challenge of Periodontist is to disentangle the controversies existing in classification of periodontal disease, pathogenesis of periodontal diseases including the role of occlusion, perio-systemic relationship, use of antibiotics, periodontal-endodontic controversy, changing practice patterns in periodontics, lasers in periodontics and many more.This book attempts to highlight and analyse the background of some of the more significant issues that have been debated in the field of periodontology in recent years. Particular emphasis has been laid upon the controversial concepts in the subject of Periodontics.