Evaluating the implant candidate 243

Chronic leukemia usually occurs after the age of 35, and its symptoms resemble those of acute leukemia. With proper treatment, the patient may resume his normal activities and live for several years. He is always prone, however, to infections and sometimes prolonged hemorrhage. This is a warning to the dentist, who may extract a tooth loosened by necrotizing ulcerative gingivitis without carefully questioning the cause of the condition. Death can occur rapidly as a result of a careless extraction. Again, because of the patient's proneness to infection and prolonged hemorrhage, implants are contraindicated for the patient with an apparently carefully controlled chronic leukemia condition.

Polycythemia. Polycythemia is a very rare condition that sometimes follows severe dysentery, car-bon monoxide poisoning, or a congenital chronic cardiac disease. It can also occur in some people with chronic pulmonary disease and resultant arterial oxygen unsaturation and in association with certain tumors and other disorders, especially those of the kidney. It may also be idiopathic.

In severe cases of polycythemia there is cyanosis and dyspnea. An increase and changes in the red blood cells and an increase in hemoglobin and in the blood volume, as well as decreased fragility and accumulation of the red blood cells in the capillaries of the skin, are some other characteristics of the condition. Any surgical or operative procedure in an individual with polycythemia should be avoided or postponed until the red blood cells and hemoglobin are reduced to normal limits. Such a patient is other-wise prone to thrombosis and infections.

Hemophilia. Hemophilia is a hereditary sex-linked disease found only in males. It is caused by a deficiency of antihernophilic globulin and is characterized by a marked tendency to bleed. Even spontaneous bleeding from the gingivae can result in serious blood loss, and a tooth extraction may end in a fatality. It goes without saying that hemophiliacs are unsuitable as implant candidates.

Some other hemorrhagic diseases that contraindicate implants are hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease), a vascular defect characterized by small thin-walled dilated blood vessels that rupture spontaneously; and Schonlein-Henoch purpura, an allergic purpura associated with streptococcal infections, acute rheumatic fever, and the administration of drugs.

Platelet defects. Because platelets are essential to blood clotting, any condition that affects the number or normalcy of platelets contraindicates implants.

Such conditions include thrombasthenia, or Glanzmann's disease, a relatively uncommon condition in which the platelets are adequate in number but a bleeding diathesis occurs. Idiopathic thrombocytopenic purpura, another hemorrhagic disorder, is characterized by spontaneous bleeding or bruising, petechiae in the skin and mucous membranes, and a marked decrease in circulating platelets. Secondary, or symptomatic, thrombocytopenic purpuras are characterized by a reduction in blood platelets. The conditions result from an underlying disease or from exposure to toxic agents. Some of the underlying conditions are connective tissue disorders; diseases affecting the bone marrow, spleen, or both; and diseases resulting secondarily from exposure to physical or chemical agents.

Anticoagulant drug therapy. Those patients who are being administered anticoagulants should be contraindicated for implant procedures unless the treatment can be temporarily suspended.

Endocrine gland disorders

The endocrine glands either directly or indirectly affect the prognosis of an implant. This section will present a brief summary of some of the temporary and permanent disruptions in normal hormone balance. Although the great majority of presenting patients will not be victim of some of the more bizarre abnormalities resulting from endocrine disorders, the disorders should be mentioned so that the operator is aware of the prognosis in such cases.

Pituitary gland disorders. The pituitary gland, or hypophysis, is the most important organ in the regulation of growth and milk production and in the control of all other endocrine glands. Therefore disturbances in this gland's functioning as a result of disease, injury, or surgery may have extreme consequences.

In early life, disturbances in the normal growth patterns because of either too much (hyperpituitarism) or too little (hypopituitarism) activity by the pituitary are reflected in the jaws and teeth. In hyperpituitarism, the bones of the face become abnormally large and coarse, with extreme enlargement of the sinuses and mandible, producing a severe Class III malocclusion. The supraeruption of the teeth produces a marked overgrowth of the alveolar process resulting in wide spaces between the teeth. On the other hand, in hypopituitarism the teeth fail to erupt completely, resulting in crowding. Usually the alveolar bone is not deep, and the depth is further reduced when teeth are lost.