Periodontal disease (PD), an inflammatory disease of tooth supporting tissues that leads to progressive loss of periodontal ligament and bone, with pocket formation and / or recession of the gums, is widespread among the world adult population and a serious public health issue. In this book, Chapter One reviews the literature about the use of probiotics in periodontal disease, including in vitro, in vivo and clinical studies, in order to improve the understanding of probiotics’ role in periodontal disease and discusses the effectiveness of their use as a therapy for periodontitis. Chapter Two studies the model of periodontitis induction by ligature and presents a protocol for performing it in rats and mice, based on the experience of the authors’ research group, to guide researchers who wish to develop the model. Chapter Three focuses on nutritional and systemic risk factors for periodontitis, focusing on modifiable common risk factors that also impact cardiometabolic disease, which can be targeted through oral and medical health professionals for improving periodontal and cardiometabolic health. Chapter Four discusses the main manifestations of gingivitis, chronic periodontitis, aggressive periodontitis, and periodontal disease resulting from systemic diseases. In addition, the authors discuss the treatment options, highlighting the conventional periodontal therapy, systemic administration of antibiotics, and surgical treatments.