Evaluation—Can the Patient be Safely Treated?

Before initiating any dental treatment, the relevant medical history provided by a “new” patient must be carefully checked, regardless of whether comprehensive therapy is anticipated or only an emergency procedure. Of particular importance are serious diseases or conditions, such as:

• Cardiovascular diseases

• Pulmonary diseases

• Renal diseases

• Endocrine diseases

• Compromised immune response

• Psychological/psychiatric conditions

Acute situations should be thoroughly discussed before treatment; these include allergies, anaphylactic reactions, but also patient fear of the treatment or even fear of the injection needle.

The dental team must be systematically prepared for emergency situations. Corresponding checklists, supplies and devices must be at hand (emergency kit, materials for cardiopulmonary resuscitation, and perhaps even a defibrillator). The classification by the American Society of Anesthesiologists (ASA) helps to establish the physical status of a diseased patient (ASA Classes I–VI; Fig. 453)

Medical Risk Factor—“Blood Thinning”

Patients with cardiac and circulatory diseases (post-myocardial infarction, Angina pectoris etc.) or other conditions (e.g., post-surgical condition, dialysis patients, thrombosis prophylaxis etc.) usually take anticoagulants:

In order to avoid life-threatening hemorrhage, the patient’s actual “Quick-time” (Cumarin) must be assessed. A Quick value of ≥ 30% usually does not affect dental or oral surgical procedures, but values between 15 and 25% demand consultation with the treating physician.

• The effect of blood-thinning medications is enhanced by non-steroidal anti-inflammatory agents such as salicylate, mefenamine acids, tetracycline, metronidazol and sulfonamides (Scully & Wolff 2002).

• Their effects will be reduced by barbiturates, glucocorticoids, alcohol, and foodstuffs with a high vitamin-K content.

The antidote for Cumarin is vitamin K; there is no antidote for the rapidly metabolized heparin. If necessary the patient may stop taking this medication for a short period of time.

Bacteremia—Endocarditis Prophylaxis

Transient bacteremia is a natural, daily occurring situation (chewing, tooth brushing). In healthy persons, oral bacteria that enter the blood stream are efficiently eliminated by the host defense system.

Infectious endocarditis (IE) is a life-threatening disease, an infection of hemodynamically exposed defects (plaque formation on heart valves), usually elicited by oral microorganisms (streptococci).

Depending upon the virulence of the etiologic microbe and the resistance of the patient, various forms of IE can be differentiated (Müller 2001):

• Acute, infectious forms Sepsis, fever, endocardial destruction; death in less than 6 weeks

• Acute/Subacute forms Intermediate forms, often elicited by enterococci

• Subacute forms Slight fever; if untreated, death between 6 weeks and 3 months

• Chronic forms Symptoms the same as subacute; death in more than 3 months

Infectious Endocarditis (IE)

A wide variety of microorganisms such as bacteria, mycoplasm, fungi, rickettsia or chlamydia can elicit IE if they enter the bloodstream due to trauma or tissue manipulation. Regions of the cardiovascular system that experience slow blood circulation or a high level of turbulence are particularly susceptible to infections.

The most frequent source of microorganisms that elicit IE is the oral cavity. The primary pathogens are gram-positive streptococci (viridans type), especially Streptococcus sanguis.

In addition to S. aureus and S. epidermis, more and more often one also observes gram-negative bacteria from the oral cavity and the upper respiratory tract that elicit IE; for example, A. actinomycetemcomitans, Hemophilus ssp., Cardiobacterium ssp., Eikenella corrodens, Kingella ssp., Capnocytophaga, Neisseria ssp.

For the protection of IE-endangered patients, bacteriocidal antibiotics of the “penicillin type” (p. 214) are recommended. As early as 1983, J. Slots and others suggested that IE prophylaxis could also include metronidazol (p.287).

Endocarditis Prophylaxis with Antibiotics

According to new guidelines from AHA (Dajani et al. 1997), the prophylactic dose of standard antibiotic (Amoxicillin) was reduced to 2 grams; in addition, no follow-up dose is now recommended; not all other Heart Associations agree.

It is comforting for hygienist to know that most of the, albeit rare, cases of endocarditis do not result from invasive, surgical treatments! Nevertheless: Oral, especially periodontal surgical procedures take place in a highly contaminated area. Expansive and/or deep surgical procedures have almost always been performed with antibiotic prophylaxis. For this reason, recommendations concerning which dental procedures require endocarditis prophylaxis were welcomed (Newman & Winkelhoff 2001).

Dental Procedures Carrying the Risk of Bacteremia

Bacteriemia will occur following all dental procedures that elicit bleeding. The endangered patient must be premedicated with the “one-shot” prophylaxis (AHA) before:

• Periodontal probing (Fig. 457 left).

• Calculus removal

• Suture removal, dressing change

• Intraligamentous anesthesia

• Tooth extraction, surgical tooth extraction

• Root tip resection

Bacteriemias of varying frequency and severity also occur after chewing hard foodstuffs (15–50%), during tooth brushing (5–25%), or during oral irrigation (25–40%; according to Neu 1994).

The percentage and number anaerobic species were approximately twice as high in patients with poor oral hygiene and advanced periodontal diseases in comparison to patients with good oral hygiene. Bacteriemia occurs in these patients also, but patients at risk for endocarditis should not abandon mechanical oral hygiene; rather, they should rinse 30 minutes beforehand with chlorhexidine