Mjm. Schaeken et al., EFFECT OF CHLORHEXIDINE VARNISH ON STREPTOCOCCI IN DENTAL PLAQUE FROMOCCLUSAL FISSURES, Caries research, 28(4), 1994, pp. 262-266
The treatment of tooth surfaces with chlorhexidine varnish may to long
lasting suppression of mutans streptococci in dental plaque. Microbiol
ogical observations following varnish treatment suggest that this prol
onged suppression might be caused by bacterial interference. To invest
igate whether physiologically related organisms, such as other Strepto
coccus species, compete with mutans streptococci in the ecosystem, we
have analyzed streptococcal populations on the tooth surface before an
d after chlorhexidine varnish treatment. Occlusal surfaces with high n
umbers of mutans streptococci were selected in human volunteers and tr
eated with chlorhexidine varnish. Analyses of sequentially collected p
laque samples confirmed that S. oralis-group streptococci returned to
baseline levels shortly after the chlorhexidine application, while Act
inomyces naeslundii populations reached prestudy or even higher levels
only several days after treatment. Mutans streptococci, however, were
below the detection level in the 14-day samples, except in 1 individu
al. The pattern of recolonization by individual Streptococcus species
after chlorhexidine application closely resembled that of cleaned enam
el surfaces: S. oralis and S. sanguis were primary colonizers while S.
gordonii became dominant at a later stage. It is concluded that after
intensive chlorhexidine treatment, a normal oral microflora reestabli
shed, characterized by low proportions of mutans streptococci.