Bacteremia resulting from dental extraction is regarded as an important cause of bacterial endocarditis, and it is therefore recommended that patients undergoing tooth extraction be given prophylactic antibiotics. As dental procedures other than extractions may also cause bacteremias, we studied a variety of dental procedures routinely used in pediatric dentistry. Blood samples for cultures were obtained 30 s after each of 13 dental operative procedures in 735 anesthetized children aged 2-16 years. Four procedures used for conservative dentistry caused bacteremias significantly more often than the baseline value of 9.4%: polishing teeth 24.5%, intraligamental injection 96.6%, rubber dam placement 29.4%, and matrix band with wedge placement 32.1%. In comparison, toothbrushing alone caused a bacteremia on 38.5% of occasions. The organisms isolated were typical of odontogenic bacteremias in that 50% of the isolates were identified as varieties of viridans streptococci. These data show that a wider variety of dental procedures than was previously documented cause bacteremia.