Chronic periodontitis is an infectious disease characterized by gingival inflammation and loss of periodontal support tissues, comprising periodontal ligament, cementum and alveolar bone.Among host proteases degrading the extra-cellular matrix, matrix metalloproteinases (mmps) seem to be highly related to tissue destruction and remodeling events in periodontal diseases.This book describes the structure, function and regulation of MMPs and also highlights their role in certain oral diseases like oral cancer, periodontitis and dental caries.