Effect of xylitol/chlorhexidine versus xylitol or chlorhexidine as single rinses on initial biofilm formation of cariogenic streptococci.
OBJECTIVE
Oral bacteria implying a natural resistance may deteriorate the antibacterial efficacy of chlorhexidine on cariogenic microorganisms. Xylitol, mostly applied via chewing gum, is known to possess favorable plaque-reducing properties. The aim of this study was to investigate the effect of a xylitol rinse formulated as pure solution or combined with chlorhexidine on the viability of Streptococcus sanguis (early colonizer of human teeth) and Streptococcus mutans (the most causal strain for caries) during initial steps of biofilm formation.


METHODS
After exposure to the test solutions, the bacteria suspended in human sterile saliva were allowed to attach to human enamel slides for 60 minutes in a preclinical flow chamber system. The bacterial vitality of suspended and attached cells was monitored using 2 fluorescent DNA stains by epifluorescence microscopy. Further parameters measured were the total bacterial cell counts on enamel slides and growth of suspended streptococci.


RESULTS
The sensitivity of S mutans to pure chlorhexidine or in combination with xylitol is contrary to the natural resistance of S sanguis to chlorhexidine. The combination of xylitol/chlorhexidine showed a statistically significant antivital effect on S sanguis cells compared to the pure agents xylitol and chlorhexidine. The bacterial cell density on enamel and bacterial reproduction on agar plates were similarly affected by the combination of xylitol/chlorhexidine or the single substances.


CONCLUSIONS
The newly discovered synergistic antivital effect of xylitol combined with chlorhexidine may contribute to the favorable potential of xylitol use for the improvement of new formulations of caries-preventive mouthrinses.
Department of Conservative Dentistry, School of Dental Medicine, University of Tübingen, Tübingen, Germany. Evi.Decker@med.uni-tuebingen.de
Eva-Maria
EM
Decker
Gabriele
G
Maier
Detlef
D
Axmann
Michel
M
Brecx
Christiane
C
von Ohle
D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000494:pharmacology*; D001422:Bacterial Adhesion; D018441:Biofilms / Q000187:drug effects*; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002710:Chlorhexidine / Q000008:administration & dosage / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003731:Dental Caries / Q000382:microbiology; D003743:Dental Enamel / Q000382:microbiology; D015194:Diffusion Chambers, Culture; D004338:Drug Combinations; D024881:Drug Resistance, Bacterial; D004357:Drug Synergism; D006801:Humans; D009067:Mouthwashes; D012463:Saliva / Q000382:microbiology; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development; D013298:Streptococcus sanguis / Q000187:drug effects* / Q000254:growth & development; D014993:Xylitol / Q000008:administration & dosage / Q000494:pharmacology*
D000891:Anti-Infective Agents, Local; D002327:Cariostatic Agents; D004338:Drug Combinations; D009067:Mouthwashes; D002710:Chlorhexidine; D014993:Xylitol