The word “pyorrhea” comes from the Greek pyon (“pus”) and rhoia (“to flow”). Thus the definition is a graphic description of the disease in which there is an outflowing of pus from the gingival (gum) tissues of the oral cavity. The term “pyorrhea” has been used in Europe since the mid-1500s and in America since the late 1800s. However, it was not until 1937 that the American Academy of Periodontology abandoned the term in favor of “periodontal disease.”

The term “periodontal disease” is used in reference to any disease of the supporting structures of the teeth. These structures include the gingiva, periodontal ligament, and alveolar bone. In simplest terms, periodontal disease can be divided into two distinct, but not mutually exclusive, disease processes. The first involves inflammation of the gingival tissues, called “gingivitis,” and the second, a destructive loss of bone and connective tissue attachment termed “periodontitis.”

Distribution, Incidence, and Epidemiology

Epidemiological research during the past 25 years indicates that periodontal disease is one of the most common diseases affecting humankind. There is a direct cause-and-effect relationship between the bacterial colonization on the surface of the tooth and the inflammation (and often consequential destruction) of the tooth’s supporting structures. The rate of destruction varies, and is dependent on the individual’s response to the bacterial irritation.

Periodontal disease is a widespread chronic disease and remains as the primary reason for the loss of teeth in the adult population throughout the world. In fact, virtually all individuals in any population exhibit manifestations of the disease.