Bacteraemia due to dental flossing.
Level 3 - non-randomized controlled study
Prospective non-randomized comparative cohort study evaluating post-intervention bacteremia across two predefined cohorts.
PubMed 19426179 · doi:10.1111/j.1600-051X.2008.01372.x
What was done
Researchers investigated the incidence and identity of bacteremia following standardized dental flossing in 60 participants: 30 with chronic periodontitis (17 males, 13 females, aged 29–75 years) and 30 with periodontal health (17 males, 13 females, aged 28–71 years). Baseline blood samples were taken after a non-invasive exam, followed by teeth flossing in a standardized manner. Blood samples were collected at 30 seconds and 10 minutes post-flossing, cultured using a BACTEC system, and subcultured for bacterial identification.
What was found
Bacteremia was detected following flossing in 40% of periodontitis subjects and 41% of periodontally healthy subjects. Viridans streptococci were isolated from 19% of positive individuals and accounted for 35% of all microbial isolates. At 10 minutes post-flossing, 20% of subjects still had detectable bacteremia. No patient or clinical factors were significantly associated with post-flossing bacteremia.
Why it matters
Routine flossing introduces oral bacteria—including species implicated in infective endocarditis—into the bloodstream at rates similar to some invasive dental procedures, regardless of whether a patient has periodontal disease.
Limits
The sample size is relatively small (60 total participants across two groups), follow-up blood cultures ended at 10 minutes, and the abstract does not assess downstream clinical outcomes such as actual endocarditis risk.
Cited by
- supports Dental flossing can push bacteria from infected gums into the bloodstream.