Influence of delmopinol on bacterial ζ-potentials and on the colloidal stability of bacterial suspensions

Abstract

Delmopinol is a low molecular weight surface-active compound that has been shown to be effective against dental plaque both in vitro and in vivo and against gingivitis in vivo. To study the mode of action of delmopinol, the influence of the compound on the stability of bacterial suspensions, both with and without saliva, and on the ζ-potentials of oral streptococci was studied. The results showed that delmopinol reduced the magnitude of the ζ-potentials, but, in contrast, the colloidal stability of the bacterial suspensions without saliva was increased. The explanation of these observations could be that non-DLVO interaction components, such as repulsive hydration/steric forces, have come into effect at very close distances between two approaching bacterial cells. To judge from the present results, it is possible that delmopinol forms films on bacterial cells in a plaque, thereby facilitating mechanical removal.

Key Words:

• Bacteria
• oral
• dental plaque
• electrophoretic mobility
• flocculation
• gingivitis
• streptococci