OBJECTIVE To estimate the cumulative exposure to bacteraemia from dental procedures currently recommended for antibiotic prophylaxis and compare this with cumulative exposure from dental procedures not recommended for prophylaxis.

DESIGN Retrospective analysis.

SETTING University and teaching hospital maxillofacial and dental department.

PATIENTS 136 children with severe congenital cardiac disease attending for dental treatment between 1993 and 1998 and for whom full records were available. Each dental procedure was tallied.

MAIN OUTCOME MEASURES Cumulative exposure per annum to “non-prophylaxis procedures”; cumulative exposure per annum to “prophylaxis procedures”.

RESULTS Cumulative exposure to bacteraemia from prophylaxis procedures was not significantly greater than from non-prophylaxis procedures.

CONCLUSIONS The data raise important questions about the appropriateness of current guidelines for antibiotic prophylaxis of bacterial endocarditis.