Evaluation of chlorhexidine substantivity on salivary flora by epifluorescence microscopy.
OBJECTIVE
To evaluate the in vivo antimicrobial activity of chlorhexidine (CHX) in saliva 7 h after its application using an epifluorescence microscopy technique.


METHODS
Fifteen volunteers performed a single mouthrinse with sterile water (SM-water) and with 0.2% CHX (SM-0.2% CHX). Saliva samples were taken at 30 s and 1, 3, 5 and 7 h after each application. The bacterial suspension was mixed with the SYTO 9/propidium iodide staining and observed using an Olympus BX51 microscope. The mean percentage of viable bacteria was calculated for each sample.


RESULTS
In comparison with baseline values, the frequency of viable bacteria decreased significantly at 30 s after the SM-0.2% CHX (P < 0.001) and presented significant antibacterial activity up to 7 h after the mouthrinse (P < 0.001). In comparison with SM-water, the prevalence of viable bacteria was significantly lower at 30 s after the SM-0.2% CHX (P < 0.001) and showed a significant antibacterial effect up to 7 h after the mouthrinse (P < 0.001).


CONCLUSIONS
Epifluorescence microscopy permits evaluating the antimicrobial activity of CHX on the salivary flora in real-time. Fluorescence assays could be particularly useful to analyse simultaneously the effect of antimicrobials that alter the cytoplasmic membrane integrity on different oral ecosystems.
Tomás
I
I
School of Medicine and Dentistry, Santiago de Compostela University, Santiago de Compostela, Spain. inmaculada.tomas@usc.es
García-Caballero
L
L
Cousido
M C
MC
Limeres
J
J
Alvarez
M
M
Diz
P
P
D000328:Adult; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D002710:Chlorhexidine / Q000008:administration & dosage / Q000494:pharmacology*; D015169:Colony Count, Microbial / Q000379:methods; D005456:Fluorescent Dyes; D006801:Humans; D050296:Microbial Viability / Q000187:drug effects*; D008856:Microscopy, Fluorescence / Q000379:methods; D008875:Middle Aged; D009067:Mouthwashes / Q000494:pharmacology*; D012016:Reference Values; D012463:Saliva / Q000187:drug effects / Q000382:microbiology*; D013997:Time Factors; D055815:Young Adult
D000890:Anti-Infective Agents; D005456:Fluorescent Dyes; D009067:Mouthwashes; D002710:Chlorhexidine