Few data exist on the risk of or prevention of IE associated with a GI or GU tract procedure. Accordingly, the Committee undertook a critical analysis of published data in the context of the historical rationale for recommending antibiotic prophylaxis for IE before a dental procedure. The following factors were considered: (1) frequency, nature, magnitude, and duration of bacteremia associated with dental procedures; (2) impact of dental disease, oral hygiene, and type of dental procedure on bacteremia; (3) impact of antibiotic prophylaxis on bactere- mia from a dental procedure; and (4) the exposure over time of frequently occurring bacteremia from routine daily activ- ities compared with bacteremia from various dental procedures. Frequency, Nature, Magnitude, and Duration of Bacteremia Associated With a Dental Procedure Transient bacteremia is common with manipulation of the teeth and periodontal tissues, and there is a wide variation in reported frequencies of bacteremia in patients resulting from dental procedures: tooth extraction (10% to 100%), periodon- tal surgery (36% to 88%), scaling and root planing (8% to 80%), teeth cleaning (up to 40%), rubber dam matrix/wedge placement (9% to 32%), and endodontic procedures (up to 20%).24 30 Transient bacteremia also occurs frequently during routine daily activities unrelated to a dental procedure, such as tooth brushing and flossing (20% to 68%), use of wooden toothpicks (20% to 40%), use of water irrigation devices (7% to 50%), and chewing food (7% to 51%).26 29,31 36 Consider- ing that the average person living in the United States has fewer than 2 dental visits per year, the frequency of bactere- mia from routine daily activities is far greater. There has been a disproportionate focus on the frequency of bacteremia associated with dental procedures rather than on the species of bacteria recovered from blood cultures. 