Poisson Analysis of Streptococcal Bond-strengthening on Saliva-coated Enamel

L. Mei, Y. Ren, H. J. Busscher, Y. Chen, H. C. van der Mei*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

19 Citations (Scopus)


The forces responsible for bond-strengthening in initial oral bacterial adhesion are unknown. Since Lifshitz-Van der Waals and electrostatic forces work instantaneously upon approach, it is hypothesized that bond-strengthening is governed by hydrogen bonding. Poisson analysis of adhesion forces observed during the retraction of bacterial probes from surfaces in atomic force microscopy can be used to analyze the nature of the adhesion forces. Streptococcal adhesion forces increased from about -0.7 to -10.3 nN when the contact time between cell surfaces and salivary films on enamel was increased from 0 to 120 sec. Initial and final adhesion forces were stronger for initial colonizers of tooth surfaces (S. mitis, S. sanguinis) than for later, more cariogenic, strains (S. sobrinus, S. mutans). Retraction curves after increased contact times showed minor peaks, representative of hydrogen bonds, and Poisson analyses indicated repulsive non-specific forces of around +0.3 nN and slightly more attractive hydrogen-bonding forces (-1.0 nN) for initial than for late colonizers (-0.8 nN).

Original languageEnglish
Pages (from-to)841-845
Number of pages5
JournalJournal of Dental Research
Issue number9
Publication statusPublished - Sep-2009


  • saliva adhesion
  • bacteria
  • enamel
  • bond strengthening
  • atomic force microscopy
  • streptococci
  • biofilm

Cite this