Substantivity of a single chlorhexidine mouthwash on salivary flora: influence of intrinsic and extrinsic factors.
OBJECTIVE
To analyse the influence of intrinsic and extrinsic factors on the in vivo antimicrobial activity of a chlorhexidine (CHX) digluconate mouthwash on the salivary flora up to 7h after its application, using epifluorescence microscopy.


METHODS
Ten volunteers performed the following mouthwashes: 0.12% CHX (10ml/30s, 15ml/30s and 10ml/1min); 0.2% CHX (10ml/30s, 15ml/30s and 10ml/1min); 0.2% CHX (10ml/30s) plus different daily activities (eating, drinking, chewing or smoking).


RESULTS
On comparing 0.12% CHX (10ml versus 15ml), the greatest differences in bacterial viability were detected at 1h and 3h. On comparing 0.12% CHX (30s versus 1min) the greatest differences in viability were detected at 1h, 3h, and 5h; and with 0.2% CHX (30s versus 1min), at 5h and 7h. On comparing 0.12% CHX (15ml) versus 0.2% CHX (10ml) and 0.12% CHX (1min) versus 0.2% CHX (30s), the percentage of viable bacteria was higher with the 0.12% concentration. On comparing 0.2% CHX versus 0.2% CHX plus daily activities, the higher differences were detected after eating and chewing, followed by drinking.


CONCLUSIONS
An increase in the volume of 0.12% or 0.2% CHX mouthwashes does not affect the duration of antimicrobial activity in saliva, whereas increasing the duration produces a marked increase in substantivity. Substantivity was greater with 0.2% CHX than 0.12% CHX. Eating, chewing or drinking significantly reduces the 0.2% CHX substantivity in saliva.
Tomás
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I
School of Medicine and Dentistry, Santiago de Compostela University, Spain. inmaculada.tomas@usc.es
Cousido
M C
MC
García-Caballero
L
L
Rubido
S
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Limeres
J
J
Diz
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P
D000328:Adult; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000627:therapeutic use*; D001419:Bacteria / Q000187:drug effects*; D002638:Chewing Gum; D002710:Chlorhexidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D015169:Colony Count, Microbial; D004326:Drinking / Q000502:physiology; D004435:Eating / Q000502:physiology; D019793:Fluorescein; D005456:Fluorescent Dyes; D006801:Humans; D008409:Mastication / Q000502:physiology; D050296:Microbial Viability / Q000187:drug effects; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009067:Mouthwashes / Q000008:administration & dosage / Q000627:therapeutic use*; D012463:Saliva / Q000382:microbiology*; D012907:Smoking; D013997:Time Factors; D014966:Xanthenes; D055815:Young Adult
D000891:Anti-Infective Agents, Local; D002638:Chewing Gum; D005456:Fluorescent Dyes; D009067:Mouthwashes; D014966:Xanthenes; C034657:Texas red; C010882:chlorhexidine gluconate; D002710:Chlorhexidine; D019793:Fluorescein