There are two forms of mouth-danger that should be clearly differentiated. Dental caries, or decay, is at first largely a chemical process and affects the tooth proper. Pyorrhea, or Riggs’s disease, affects the tissues surrounding the root of the tooth, and is accompanied with infection by pus bacteria, and possibly also by animal parasites, termed endameba. Scrupulous cleanliness of the mouth largely prevents both of these maladies.
Dental Decay
In caries, or dental decay, plaques or films of mucin from the saliva form on the tooth-surfaces and enclose bacteria and particles of carbohydrate food, which undergo fermentation with the formation of lactic acid, which dissolves the lime salts on the surface of the teeth, leaving only the organic matter. This organic matter is then attacked by bacteria. Putrefaction sets in, and you have a cavity. This cavity is, of course, a menace, as it harbors various forms of bacteria, which may infect the general system through the root canals, or the digestive system by being swallowed with the food, and also gives rise to abscesses at the root-tips.
Pyorrhea
Pyorrhea is an infection of the gums or tooth-sockets. It begins beneath the edges of the gums that have been injured and especially where there has been an accumulation of tartar or lime-deposit. As the infection progresses and destroys the membranes that attach the root of the tooth to the socket, a pocket is formed around the root, and the tooth becomes loosened. It is said that this disease is responsible for far more loss of teeth than is decay.
Systemic Injuries from Mouth Infection
But this is not the only evil. In the pocket pus is continually being formed and discharged into the mouth and swallowed. Also, as the teeth rise and fall in their diseased sockets in ordinary chewing, bacteria are forced into the circulation and may be carried to distant parts, where they work harm according to their nature, selecting tissues for their operation in which they can best thrive.
Focal Infection
It was formerly supposed that the ill effects from such conditions as dental abscess and other pus foci were wholly due to the toxins or poisonous products thrown into the blood-stream by the bacteria at the focus. It is now known, however, that the bacteria migrate into outside tissues through the blood- and lymph-streams. In joint affections, they clog and obstruct the small blood-vessels, interfering with the nutrition of the joint-tissues, causing deformity and enlargement, as in arthritis deformans, as well as in acute inflammation, such as rheumatic fever. Indeed, this condition of subinfection, or “focal infection,” is coming to be recognized as a far more important cause of disease than the time-honored autointoxication, a term which has been greatly abused and misused.
Autointoxication