One human mouth is home to more microorganisms than there are people on our planet earth. The wide array of habitat renders the mouth a microbial paradise, offering preferred accommodations on the cheek, or on the back of the tongue in an anaerobic crevice, or in the moist, oxygen-deprived area between the tooth surface and the adjacent periodontal tissues.
The mouth's microbial ecology, however, is extremely sensitive to the challenges that confront its human host throughout the lifespan and, therefore, can often change precipitously. From fetal life through senescence, the mouth's continued exposure to opportunistic infectious pathogens is in balance with host immunity; the balance between these profoundly important processes often serves as a mirror for the detection of not only oral pathology, but also major systemic diseases.
It is especially in the soft tissues that this relationship is played out. The lips, tongue, gums, salivary glands, and oral mucosa can all warn of trouble in our general health. Because of their exquisite positioning in the body, these tissues and their fluids form a protective barrier of mucosal immunity to the outside world that when breached, signal clinical disease. They tell of direct assaults by a broad range of systemic disorders such as diabetes, AIDS and Sjögren's syndrome, as well as complications of treatments like cancer chemotherapy and radiation. For some disorders, particularly AIDS and diabetes, oral tissues may reveal lesions or pathology that are the first signs of systemic disease.
The periodontium, comprised of the gingiva, bone and other supporting tissues that anchor the teeth, plays a key role in the interplay between oral health and systemic disease. Infection in these tissues, primarily by gram-negative anaerobic bacteria, can initiate a series of inflammatory and immunologic changes leading to the destruction of connective tissue and bone. Long considered a localized infection, periodontal diseases are now linked to a variety of conditions with systemic implications.
Oral Health & Wellness Content provided by NIH