Dental polyelectrolyte cements. I. Chemistry of the early stages of the setting reaction.

As part of an investigation of the setting of dental polyelectrolyte cements, the chemistry of a selection of glass ionomer and zinc polycarboxylate cements was studied by pH, conductivity and I.R. measurements. The zinc polycarboxylate cements were found to react at a greater rate than the glass ionomer cements. The effect of reducing the powder/liquid (P/L) ratio is to decrease the surface area available to attack and hence the reaction rate. The basic form of the kinetics appears to be unaffected except for low P/L ratios where there is a deficiency of available metal cations.