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Clinical question.
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Does prophylactic antibiotic administration before invasive dental procedures in people at increased risk of bacterial endocarditis influence mortality, serious illness or endocarditis incidence?
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Review methods.
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The authors conducted a comprehensive search of six electronic databases from 1950 through June 2008. The initial search identified 980 abstracts of which the authors reviewed 118 full articles. The authors excluded 83 articles because they were discussion articles, editorials or guidelines and 34 articles because they were duplicate studies. They included one article, which was a case-control study.
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Main results.
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The one study that was included reported on all cases of endocarditis in the Netherlands during a two-year period from November 1986 through November 1988, according to the authors. In the study, the authors defined cases as patients who had a predisposing cardiac disease and had undergone a medical or dental procedure with a definite or possible indication for prophylaxis and developed endocarditis within 180 days of this procedure. In the study, control patients had one of the following pre-existing conditions: congenital heart defect, history of rheumatic fever, high risk of developing endocarditis with prosthetic heart valves or a history of endocarditis. Control patients were matched for age and had undergone a medical or dental procedure with a definite or possible indication for prophylaxis and had not developed endocarditis within 180 days of the procedure. Indications for "definite prophylaxis" were dental extraction and "dental root work," and an indication for "possible prophylaxis" was dental scaling.
Of 349 patients who developed native-valve endocarditis, 44 had undergone dental treatment with a definite or possible indication for prophylaxis. Seven of these patients had been treated with prophylactic antibiotics before the dental procedure. Of the patients meeting the criteria for the control group, 181 had undergone a dental procedure with a definite or possible indication for prophylaxis. Seventeen of the control patients had been administered prophylactic antibiotics before they underwent the dental procedure. The odds of development of endocarditis among those receiving antibiotic prophylaxis was 1.62 (95 percent confidence interval, 0.57–4.57).
The authors did not locate any studies that assessed mortality, illness or other adverse effects. Since no conclusive evidence supporting a benefit was identified, the authors did not look for information on harms.
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Conclusion.
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There is no evidence that antibiotic prophylaxis is effective or ineffective against bacterial endocarditis when it is administered before an invasive dental procedure in people who are at risk of developing the disease.
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COMMENTARY
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Importance and context.
Bacterial endocarditis is a serious, but rare, condition that can be caused by bacteria from the oral cavity. The clinical practice of antibiotic prophylaxis to prevent endocarditis has been evolving for more than 50 years. The objective is to prevent endocarditis arising from transient bacteremia that may be caused by dental procedures. Antibiotic prophylaxis recommendations are based largely on expert opinions and limited evidence. No clinical evidence has established a link between antibiotic prophylaxis and the prevention of bacterial endocarditis in at-risk patients.
Recently, the American Heart Association and the National Institute for Health and Clinical Excellence in the United Kingdom have reviewed guidelines for antibiotic prophylaxis. Current American Heart Association guidelines recommend antibiotic prophylaxis in patients with underlying cardiac conditions associated with the highest risk of adverse outcomes from endocarditis who undergo dental procedures that involve the manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa.1 In contrast, the National Institute for Health and Clinical Excellence does not recommend antibiotic prophylaxis for any at-risk patient undergoing a dental procedure unless there is suspected infection.2 Differences in such recommendations have caused much debate and continue to stir controversy in the international medical and dental communities.
Strengths and weaknesses of the systematic review.
The review’s authors used accepted methods to identify and select studies. The authors also assessed the internal and external validity of the case-control study. The review’s authors recognized the limitations of basing conclusions on one observational study with retrospective case-control design. Although the case-control study analyzed medical and dental procedures separately, the authors of the systematic review provided the analysis.
Strengths and weaknesses of the evidence.
One case-control study constitutes a weak body of evidence. The selected study was based in the Netherlands over a two-year period. A randomized controlled trial would be a challenge owing to the relatively low incidence of endocarditis in the general population and to bioethical considerations.
Implications for dental practice.
The review of the evidence provides no definite conclusion about the administration of antibiotic prophylaxis to patients before they undergo dental procedures in an effort to prevent bacterial endocarditis. The global community continues to deliberate about the efficacy of antibiotic prophylaxis in the prevention of bacterial endocarditis. Until more evidence is available or a universally accepted guideline is established, practitioners in the United States should continue to follow the most recent American Heart Association guidelines on antibiotic regimens for dental procedures.1
TOP
Clinical question.
Review methods.
