Journal of Dental Research, Vol 65, 1142-1148, Copyright © 1986 by International & American Associations for Dental Research Online Journals
Antimicrobial properties of hydrogen peroxide and sodium bicarbonate individually and in combination against selected oral, gram-negative, facultative bacteria
K. T. Miyasaki, R. J. Genco and M. E. Wilson
The topical application of hydrogen peroxide (H2O2) and sodium bicarbonate
(NaHCO3), individually and in combination, has been used empirically in the
treatment of periodontal diseases. In this study, we examined both minimum
inhibitory concentrations (MIC) and minimum bactericidal concentrations
(MBC) of these disinfectants individually and in combination against
selected facultative, Gram-negative oral bacteria in a microtiter dilution
assay. The bacteria studied included Actinobacillus actinomycetemcomitans,
Haemophilus aphrophilus, Eikenella corrodens, and Capnocytophaga
gingivalis. These bacteria exhibited MBC (one hr) values ranging from 75
mumol/L to greater than 10 mmol/L and MIC from less than 5 to 500 mumol/L
for H2O2. The tested bacteria exhibited MIC values for NaHCO3 of from 23 to
182 mmol/L, and the MBC (one hr) exceeded 728 mmol/L for most of the
strains examined. At sublethal (sub-MIC) concentrations, sodium bicarbonate
antagonized the ability of H2O2 to inhibit bacterial growth in MIC assays,
but sublethal concentrations of H2O2 had no effect on the MIC values of
NaHCO3. Lethal concentrations of H2O2 and NaHCO3 exhibited synergistic
antimicrobial activity in combination in one-hour bactericidal assays.
Since the bactericidal properties of these antimicrobial agents are
synergistic, we conclude that it may be rational to use them in combination
to treat certain forms of periodontal disease. Also, lower and perhaps
safer concentrations of H2O2 can be used in combination with NaHCO3 when
oxidative antimicrobial chemotherapy is indicated.
