Purpose: To compare and contrast antibacterial activities of a baking
soda-containing dentifrice, Arm and Hammer Dental Care (AHDC) with two
fluoride dentifrices without baking soda (Crest and Colgate). Materia
ls and Methods: A biphasic approach was taken, utilizing newly-develop
ed laboratory model systems to: (1) assess the activity of brief expos
ure to dentifrices on single and mixed cultures; and (2) determine the
effect of multiple, short-term exposure of sucrose-colonized Streptoc
occus mutans to simulate cumulative activity against cariogenic plaque
. Results: The short-term exposure assays revealed that S. mutans was
significantly more susceptible to AHDC than either Crest or Colgate (P
< 0.05). Moreover, exposure of mixed suspensions of bacteria by AHDC r
esulted in complete killing of Actinomyces viscosus and significantly
greater decreases in S. mutans (P< 0.05). This enhanced bactericidal e
ffect was not due to an alkaline pH as pH-adjusted AHDC solutions exhi
bited similar activity. The comprehensive in vitro plaque studies show
ed that exposure of colonized S. mutans to AHDC resulted in significan
tly greater decreases in numbers of viable cells than Crest (P< 0.05).
Under the conditions employed, the baking soda-containing AHDC exhibi
ted greater antibacterial efficacy overall than the standard Crest or
Colgate pastes. These studies suggest that the use of AHDC may provide
additional clinical benefit as a result of the enhanced bactericidal
activity.