Effect of sodium lauryl sulfate on protein adsorption to hydroxyapatite in vitro and on pellicle formation in vivo.

Sodium lauryl sulfate (SLS) is widely used as a synthetic detergent in dentifrices. It has been shown to have high affinity for hydroxyapatite (HA), and the binding mechanism has been proposed to be electrostatic, involving the negative sulfate terminals of the SLS and the calcium sites on the HA. The binding of SLS to HA may thus well interfere with the protein adsorption to HA. The aim of the present study was to examine the effect of SLS on protein adsorption in vitro and on pellicle formation in vivo. The effect on protein adsorption was studied using ion exchange chromatography. The effect on pellicle formation was studied using enamel fragments carried in the mouth. The study showed that SLS-treated HA adsorbed less protein than untreated HA. Protein adsorbed to SLS-treated HA was more firmly bound to HA as compared to untreated HA. SLS-treated enamel fragments carried in the mouth showed a slower rate of pellicle formation than non-treated enamel.