228 Theories and techniques of oral implantology

patient may live without treatment for several months, although unless treated the patient will die from the disease.

Because patients with heart defects or chronic heart diseases are particularly prone to bacterial endocarditis, the dentist should carefully approach any procedure, no matter how simple, that may allow bacteria to enter the bloodstream. Deaths in-directly arising from a tooth extraction or an abscessed tooth have not been rare. If an implant intervention is contemplated in such a patient, penicillin or some other antibiotic should be ad-ministered prior to, during, and after the surgical visits. On the day of the surgical visit, if the patient has a sore throat or any other sign of infection, the implant procedure should be postponed and more intensive antibiotic treatment initiated.

Rheumatic heart disease. Rheumatic heart disease is the second most common form of heart disease in American adults and accounts for over 90% of all heart disorders in children. The condition usually results from having had rheumatic fever, and about 50% of all patients who have had rheumatic fever have developed some heart complications that usually affect the myocardium and valves.

Rheumatic fever usually occurs between the ages of 6 and 19 years and almost always follows a streptococcal infection. There is some evidence that heredity plays a role in susceptibility to the disease. Rheumatic heart disease may be an allergic reaction to the presence of the bacterium. Once a person has had rheumatic fever, he must be alert for recurrent attacks. He should avoid people with strep throats and other streptococcal infections and should immediately consult his physician if he gets a strep infection. Antibiotics and sulfonamides can usually control the infection and prevent further episodes of the disease.

As soon as the dentist learns that a patient has had rheumatic fever, he should approach implantation cautiously. Because of the high percentage of heart defects resulting from rheumatic fever, there is always the danger of bacterial endocarditis. Antibiotics should be administered throughout the course of an implant intervention if other conditions permit contemplating an implant. The nature of the patient's heart damage will affect the type of anesthetic. Generally a local anesthetic is preferred.

Allergies

One out of ten Americans is hypersensitive, or allergic, to certain foods, drugs, pollens, dusts,

Fig. 6-35. These lesions resulted from an allergic reaction and are typical of those produced by a drug allergy. (From Bhaskar, S. N.: Synopsis of oral pathology, ed. 3, St. Louis, 1969, The C. V. Mosby Co.)

fabrics, plants, bacteria, animals, metals, and many other substances. Most of these substances are either protein in nature or combine with one of the body proteins, making them foreign to the body. When the individual comes in contact with the allergen, or substances capable of producing the allergic reaction, he may sneeze, wheeze, cough, swell, or itch. The response depends upon the particular site affected by the allergen, and the sites most commonly affected are the skin and mucous membranes (Fig. 6-35).

An allergy is an immune reaction gone wrong. Normally when a foreign substance enters the body, the body responds by sending white blood cells to the invasion site and by producing antibodies. These antibodies are highly specific; they combine with the particular foreign substance and render it harm-less. Usually more antibodies are produced than are needed to combat the particular invader, and thus the individual is immune to new invasions for some time. The period of immunity may last a few days to a lifetime. Thus a person who has successfully fought off a common cold does not catch it again for several weeks, and a child who has had chickenpox never again gets the disease.

The immune reaction is thus one of the body's natural defenses against disease-causing microorga-