* However, numerous other dental procedures have been re- ported to be associated with risks of bacteremia that are similar to that resulting from tooth extraction. A precise determination of the relative risk of bacteremia that results from a specific dental procedure in patients with or without dental disease is probably not possible.27,72,73 Bleeding often occurs during a dental procedure in patients with or without periodontal disease. Previous AHA guide- lines recommended antibiotic prophylaxis for dental proce- dures in which bleeding was anticipated but not for proce- dures for which bleeding was not anticipated.1 However, no data show that visible bleeding during a dental procedure is a reliable predictor of bacteremia.62 These ambiguities in the previous AHA guidelines led to further uncertainties among healthcare providers about which dental procedures should be covered by prophylaxis. *References 23, 24, 27, 29, 45, 48, 52, 54, 57, and 65 67. References 27, 28, 47, 51, 54, 56, 58, and 68 71. Wilson et al Prevention of Infective Endocarditis 1741 These factors complicated recommendations in previous AHA guidelines on prevention of IE that suggested antibiotic prophylaxis for some dental procedures but not for others. The collective published data suggest that the vast majority of dental office visits result in some degree of bacteremia; however, there is no evidence-based method to decide which procedures should require prophylaxis, because no data show that the incidence, magnitude, or duration of bacteremia from any dental procedure increase the risk of IE. Accordingly, it is not clear which dental procedures are more or less likely to cause a transient bacteremia or result in a greater magnitude of bacteremia than that which results from routine daily activities such as chewing food, tooth brushing, or flossing. 