A method to study sustained antimicrobial activity of rinse and dentifrice components on biofilm viability in vivo

HC van der Mei*, DJ White, J Atema-Smit, E van de Belt-Gritter, HJ Busscher

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

37 Citations (Scopus)


Aim: To develop an improved method for quantitative assessment of antimicrobial efficacy and substantivity of mouth rinses and dentifrices on in vivo treated plaque.

Materials and Methods: Nine- and 72-h-old plaques were formed in volunteers carrying out standardized hygiene using NaF-containing dentifrice. Plaques were collected before (baseline) in vivo treatment with dentifrices or chlorhexidine mouth rinse, immediately post-treatment and after 1 or 6 h, dispersed in demineralized water and stained with live/dead stain after which bacteria were enumerated. Dispersed baseline plaques were treated with dentifrices or chlorhexidine to determine antimicrobial efficacy against planktonic bacteria.

Results: Baseline plaques revealed 56-41% viable organisms in 9- and 72-h-old plaques, respectively. Treatment of planktonic (dispersed baseline plaque) bacteria resulted in 1-4% viable organisms. Chlorhexidine mouth rinse and dentifrices produced strong immediate antimicrobial effects, but after 1 or 6 h, the proportion of viable organisms in 9-h-old plaques rebounded significantly with only chlorhexidine mouth rinse retaining significant efficacy. Seventy-two-hour-old plaques were less susceptible to antimicrobials, although dentifrices appeared more effective after 6 h than initially, whereas efficacy of chlorhexidine rinse continued to drop with time post-treatment.

Conclusions: The proposed method holds promise for assessment of both immediate and retained antimicrobial actions of oral treatments against dental plaque in vivo.

Original languageEnglish
Pages (from-to)14-20
Number of pages7
JournalJournal of Clinical Periodontology
Issue number1
Publication statusPublished - Jan-2006


  • chlorhexidine mouth rinse
  • confocal scanning laser microscopy
  • dentifrices
  • plaque
  • substantivity

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