Js. Vanderhoeven et Mjm. Schaeken, STREPTOCOCCI AND ACTINOMYCES INHIBIT REGROWTH OF STREPTOCOCCUS-MUTANSON GNOTOBIOTIC PET MOLAR TEETH AFTER CHLORHEXIDINE VARNISH TREATMENT, Caries research, 29(2), 1995, pp. 159-162
Clinical studies suggest that the long-term suppression of mutans stre
ptococci on tooth surfaces after intensive chlorhexidine therapy is ma
inly due to bacterial interference. Other streptococci and also Actino
myces naeslundii are proposed to inhibit regrowth of mutans streptococ
ci after suppression by the agent. We have tested this hypothesis in g
notobiotic rats associated with Streptococcus mutans alone, or associa
ted with S. mutans and strains of Stveptococczu oralis, Streptococcus
sanguis, Streptococcus gordonii, Streptococcus mitis biovar I, and A.
naeslundii. Left lower jaws in these rats were treated with concentrat
ed chlorhexidine varnish, and the return of S. mutans on the treated j
aws monitored. In monoassociated rats, S. mutans regained the level of
the untreated right lower jaw in approximately 1 week. In contrast, S
. mutans remained suppressed for several weeks in rats multi-associate
d with other streptococci and actinomyces strains. The suppression was
more pronounced in the rats fed on basal diet with little free sugars
than in rats fed on a sucrose-containing diet. Counts of other strept
ococci recovered quickly from the intensive chlorhexidine treatment, b
ut A. naeslundii remained suppressed for at least I week. The findings
demonstrate the crucial importance of the oral microflora in controll
ing regrowth of mutans streptococci after chemotherapy.