CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 9, October 2012
AFRICA
493
bacteraemia associated with dental extraction was investigated
by Lockhart
et al
.
15
There was a statistically significant decrease
in the cumulative incidence of endocarditis-related bacteraemia
in the amoxicillin group (33 vs 60%).
In contrast to these studies, Hall
et al.
allocated 60 patients to
receive placebo, penicillin V (2 g) or amoxicillin (3 g) one hour
before dental extraction and used a lysis-filtration technique to
process the blood samples.
16
The overall incidence of bacteraemia
after the extraction was 90, 90 and 85% in the three groups,
respectively. The differences in the incidence of bacteraemia
among the three groups were not statistically significant.
The lack of reduction in both incidence and magnitude of
bacteraemia in the two penicillin groups was not due to high
minimum inhibitory concentrations or minimum bactericidal
concentrations. For all strains except two, the minimum inhibitory
concentrations and the minimum bactericidal concentrations
were below the antimicrobial serum concentrations that were
measured during the dental procedure.
The incidence of post-extractionbacteraemia after clindamycin
prophylaxis in our study was 20%. Compared to the control
group (35%), this difference was not statistically significant. No
streptococci were cultured in the clindamycin group.
Aitken
et al.
compared the efficacy of oral doses of 600 mg
of clindamycin and 1.5 g of erythromycin in the prevention of
post-extraction streptococcal bacteraemia in 40 patients.
17
Forty
five per cent of patients who had taken clindamycin and 60%
of those who had taken erythromycin developed streptococcal
bacteraemia; statistical tests were not done.
Clindamycin caused fewer adverse gastrointestinal effects
than erythromycin. Mean levels of both drugs were not
significantly different in those with and without streptococcal
bacteraemia. Serum antibiotic levels exceeded the minimum
inhibitory concentrations for oral streptococci.
Using a lysis-filtration technique to process blood samples,
Hall
et al.
compared the efficacy of clindamycin 600 mg orally
and erythromycin 1 g orally given 1.5 hours before dental
extraction in 38 patients.
18
The overall incidence of bacteraemia
with viridans streptococci was 74% in the clindamycin group
and 79% in the erythromycin group; the difference between the
groups was not statistically significant. All viridans streptococci
(
except for one strain) were susceptible to both drugs. In the
study by Göker and Güvener, the prevalence of bacteraemia
immediately following surgical removal of impacted third molars
was similar in the group given clindamycin and the control group
(40
and 44%, respectively).
19
The efficacy of amoxicillin, clindamycin and moxifloxacin
was compared by Diz Dios
et al
.
20
The prevalence of post-
extraction bacteraemia in the control, amoxicillin, clindamycin
and moxifloxacin groups at 30 s was 96, 46, 85 and 57%,
respectively and at 15 min, it was 64, 11, 70 and 24%,
respectively. When compared to the control group, the reductions
in the amoxicillin and moxifloxacin groups were statistically
significant. Our results also showed a significant reduction for
amoxicillin but not for clindamycin.
Chlorhexidine did not reduce the incidence of post-extraction
bacteraemia in our study. Bacteria were cultured in 40% of
patients in the chlorhexidine group compared to 35% in the
control group. Lockhart carried out a randomised, double-
blind, placebo-controlled study in 70 patients to evaluate the
antibacterial effect of mouth rinses with chlorhexidine in patients
having a single extraction.
8
Blood cultures after dental extraction
were positive for organisms in 94% of 33 patients in the control
group and in 84% of 37 patients in the chlorhexidine group;
differences were not statistically significant.
Lockhart
8
and Lockhart and Schmidtke
21
have drawn
attention to the fact that antimicrobial rinses and irrigations
do not permeate more than 3 mm into the gingival sulcus and
therefore do not reach the area where bacteria gain entrance into
the systemic circulation. However, chlorhexidine produced a
statistically significant reduction in post-extraction bacteraemia
in another study (96 vs 79% at 30 s and 64 vs 30% at 15 min.)
22
Conclusion
Since studies on the efficacy of antibiotic prophylaxis of
infective endocarditis in humans cannot be done for ethical
and practical reasons, clinical studies have focused on the
prevention of bacteraemia by administration of antimicrobial
agents before dental treatment. Our study showed that none
of the treatments prevented post-extraction bacteraemia and
confirmed earlier reports that bacteraemia is not completely
eliminated by antibiotics.
1,23-25
It is noteworthy that after reviewing the data on antibiotic
prophylaxis, theBritishSociety forAntimicrobialChemotherapy
26
and the American Heart Association
27
recommended prophylaxis
for high-risk patients undergoing dental procedures. However,
the National Institute for Health and Clinical Excellence (NICE)
did not recommend antibiotic prophylaxis against infective
endocarditis for patients undergoing dental procedures.
7
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