Teaching Evidence-Based Dentistry by Using the American Heart Association 2007 Guidelines on Antibiotic Prophylaxis for Prevention of Infective Endocarditis

Geist, Shin-Mey R., James R. Geist, and Teresa Jeo-Chen Yin

Evidence-based clinical practice guidelines have been very helpful in the practice of evidence-based medicine and evidence-based dentistry (EBD). These guidelines, which are periodically updated, have a clear level of evidence quality and strength of recommendations. They provide clinicians with sound guidance in making clinical decisions about selecting the treatment that best benefits their patients. The guidelines are also good tools for teaching EBD because they can serve as examples of patient assessment, evidence appraisal, and clinical decision making, the essential elements of EBD. We chose the American Heart Association (AHA)’s 2007 guidelines on antibiotic prophylaxis (AP) for infective endocarditis (IE) prevention as a model of EBD teaching because of their relevance and frequent application in dentistry. Also, they have a simple scale of evidence level (Levels A through C), strength of recommendation (Class I through III), and suggested phrases used in recommendations. The Class IIa recommendation classification (reasonable instead of recommended) for AP use is especially valuable for critical thinking exercises in EBD regarding implementing the guidelines. We examined dental students’ cognitive level of the specific AP guidelines and their application after classroom and clinical instruction to reflect the effectiveness of EBD teaching. In January 2010 the eighty-seven third-year dental students began their first course in oral medicine, in which the AP guidelines were discussed in the context of EBD. The second oral medicine course began in May 2010 and reinforced the application of these guidelines in more complex case scenarios. During this period, the students were treating patients in the clinic and routinely screened their patients for any heart condition for which AP was deemed reasonable according to the 2007 guidelines. Questions in case scenario and multiple-choice format regarding the guidelines were included on the final examination for the first oral medicine course in April 2010. Similar questions with more complex scenarios were included on the examination in the second oral medicine course in July. Point-biserial correlation and p-values were used for assessing students’ cognitive level. Results of the first exam revealed correct responses on the questions ranging from 14.0 percent of the class to 93.0 percent. More students who scored in the upper 27 percent of the class on the overall exam responded correctly on each question compared to students in the lower 27 percent (point biserial 0.24 to 0.36 for these questions). On the second examination, the percentage of correct responses to the questions regarding the guidelines ranged from 20.0 percent to 87.7 percent. For all questions except one, greater numbers of students in the upper 27 percent responded correctly than students in the lower 27 percent (point biserial 0.27 to 0.63). On both examinations, students did better with questions involving clear-cut answers, such as whether AP is recommended or not recommended (Class I or III). They did not score as well with questions regarding strength of recommendation, such as when AP is reasonable or may be considered (Class IIa or IIb) as opposed to recommended. This was especially a problem for the students who scored poorly overall on the exams. The results indicate that more instruction is needed in interpretation of strength of recommendations in the guidelines and application of critical thinking in making judgments to implement the specific recommendations in guidelines. Our investigation indicates that students have a difficult time interpreting the meaning of classification of recommendations in the AHA’s 2007 guidelines on AP for IE prevention. It suggests that more instruction is needed, especially for weaker students, in understanding the guidelines’ true meaning as a guide in making judgments in clinical situations when practicing EBD.