Original Paper

Effects of Amine Fluoride on Biofilm Growth and Salivary Pellicles
H.C. van der Mei, E. Engels, J. de Vries, H.J. Busscher

Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands

Address of Corresponding Author

Caries Res 2008;42:19-27 (DOI: 10.1159/000111746)

  Key Words

• Amine fluoride
• Dental plaque
• Hydrophobicity
• Mutans streptococci
• Streaming potentials
• Water contact angles
• X-ray photoelectron spectroscopy

  Abstract

The amine fluoride (AmF) N'-octadecyltrimethylendiamine-N,N,N'-tris(2-ethanol)-dihydrofluoride is a cationic antimicrobial which can have beneficial effects on plaque formation. Here, we determine changes in pellicle and bacterial cell surface properties of the strains Actinomyces naeslundii HM1, Streptococcus mutans NS, S.mutans ATCC 700610, S. sobrinus HG1025 and S. oralis HM1 upon adsorption of this AmF and accompanying effects on bacterial adhesion and biofilm growth. In vitro pellicles had a zeta potential of -12 mV that became less negative upon adsorption of AmF. The chemical functionalities in which carbon and oxygen were involved changed after AmF adsorption and AmF-treated pellicles had a greater surface roughness than untreated pellicles. Water contact angles in vitro decreased from 56 to 45° upon AmF treatment, which corresponded with water contact angles (44°) measured intraorally on the front incisors of volunteers immediately after using an AmF-containing toothpaste. All bacterial strains were negatively charged and their isoelectric points (IEP) increased upon AmF adsorption. Minimal inhibitory concentrations were smallest for strains exhibiting the largest increase in IEP. Adhesion to salivary pellicles and biofilm growth of the mutans streptococcal strains were significantly reduced after AmF treatment, but not of A. naeslundii or S. oralis. However, regardless of the strain involved, biofilm viability decreased significantly after AmF treatment. The electrostatic interaction between cationic AmF and negatively charged bacterial cell surfaces is pivotal in establishing reduced biofilm formation by AmF through a combination of effects on initial adhesion and killing. The major effect of AmF treatment, however, was a reduction brought about in biofilm viability.

Copyright © 2007 S. Karger AG, Basel

  Author Contacts

H.C. van der Mei
Department of Biomedical Engineering (Sector F)
University Medical Center Groningen and University of Groningen, PO Box 196
NL-9700 AD Groningen (The Netherlands)
Tel. +31 50 3633 140, Fax +31 50 3633 159, E-Mail h.c.van.der.mei@med.umcg.nl

  Article Information

Received: February 16, 2007
Accepted after revision: September 21, 2007
Published online: November 27, 2007
Number of Print Pages : 9
Number of Figures : 7, Number of Tables : 2, Number of References : 17