Lubrication of saliva substitutes at enamel-to-enamel contacts in an artificial mouth.

Mechanisms of salivary lubrication can be quantitatively measured by a reduction in the coefficient of friction. It is important that lubrication be assessed under the conditions of the oral cavity to properly assess lubrication regimes. The relative lubricity of three artificial salivas and two controls were assessed at a bovine enamel interface in an artificial mouth with a range of conditions that approximate oral function. Statistical analysis indicated that the enamel lubricity of sodium dodecylsulfate (SDS) and Oracare-D saliva substitutes were different from the other saliva substitutes and water. The low friction with Oracare-D and SDS saliva substitutes was because of resident amphipaths adsorbed at the enamel interface. Amphipaths adsorbed on enamel may provide a reduction in interocculsal friction and its resulting complications for patients with xerostomia.