On salivary interactions with the antiplaque agents delmopinol and chlorhexidine: An experimental in vitro study

Abstract: Several chemical agents have been used to aid in the removal of dental plaque and to prevent or decrease the occurrence of oral diseases, Defining the interactions of chemical agents and saliva contributes to a better understanding of the mechanisms involved in chemical plaque control. The aim of this thesis was to investigate the salivary interactions between two antiplaque agents and saliva and microorganisms at defined solid/liquid and air liquid interfaces. The plaque control agents used in this study were delmopinol and chlorhexidine in varying concentrations. Sample of polled whole saliva collected from 16 subjects were used for adsorption experiments to solid surfaces. Whole saliva from one individual was used to study the adsorption of chemical agents to bacterial cell walls. Whole saliva samples from five subjects were used to study the binding or precipitation of salivary components by the antiplaque agents in solution. The interactions between the chemical antiplaque agents and the salivary components were investigated with ellipsometry, tensitometry, electrophoresis, video-densitometry, electrobloting, and radiolabeling. The results indicate that chlorhexidine is a surface active compound that has the capability to adsorb onto bare solid surfaces of well-defined chemical characteristics and onto surfaces preconditioned with salivary films. Chlorhexidine and delmopinol were shown to have binding sites for salivary proteins and to induce precipitation of salivary proteins. Delmopinol appears to precipitate more high molecular weight salivary proteins than chlorhexidine. It was also demonstrated that the composition of saliva as well as the concentration of chlorhexidine or delmopinol play a role in the amount of salivary proteins precipitated. In addition, chlorhexidine and delmopinol were round to bind to the salivary films coating the tested bacteria. The substantivities of both agents are related to their binding capabilities to salivary proteins. Thus, interactions between chemical agents and salivary components influence the availability of salivary components to the biofilms.