X-ray Photoelectron Spectroscopic Studies of the Adsorption of Salivary Constituents on Enamel

Abstract

Time-dependent change of adsorption of salivary components on the outermost surface layer of enamel was studied by x-ray photoelectron spectroscopy. Adsorption of proteinaceous components, as monitored in terms of the relative mass of nitrogen, was detected within 30 min, increased with time, and reached a plateau at 90 min. Thus, the ratio of nitrogen to calcium in the two-hour sample increased to about 240 times that in the control sample. The ratio of carbon to nitrogen on the surface decreased to about one-half of that in the control sample. The data established the time required for equilibrium between the proteinaceous component in saliva and the amount of material adsorbed onto the tooth surface.

Elemental Surface Concentration Ratios and Surface Free Energies of Human Enamel after Application of Chlorhexidine and Adsorption of Salivary Constituents

“…Fur thermore, calcium and phosphorous signals remain in approximately the same P/Ca concentration ratios after adsorption, but in reduced absolute intensities which suggests either that thick adsorbed layers al most fully cover the enamel surface, possibly contain ing small cracks, or that at least under high vacuum conditions the adsorbed layers are very thin, within the range of the XPS information depth. The elemen tal surface concentration ratios of enamel after in vitro adsorption of proteins from clarified human whole saliva are in remarkable agreement with recent results from Kuboki et al [1987], studying adsorption of salivary constituents on enamel by putting enamel slabs in the mouth of subjects for 30-120 min, fol lowed by thorough rinsing. This agreement between in vivo and in vitro results on salivary protein adsorp tion demonstrates the validity of our method to han dle saliva and the adsorption setup as a whole.…”

“…This clearly indicates a calcium deficiency, corresponding with the data of Kuboki et al [1987]. Although Arends et al [1979] argued that the outer 10-20 nm of the enamel surface is Ca deficient (1.40 < C a/P < 1.45), the Ca deficiency generally obtained in XPS studies is much greater and (according to the sample prepara tion in this study) extending to deeper parts of the en amel.…”

“…plications [Hercules and Craig, 1976;Uchtmann and Duschner, 1982] or the adsorption of salivary consti tuents [Kuboki et al, 1987].…”

Composition of Pellicles Formed in vivo on Tooth Surfaces in Different Parts of the Dentition, and in vitro on Hydroxyapatite

“…Pellicle formation reaches a plateau 60-90 min after exposure of a cleaned tooth surface to the oral environment [Sønju and Rølla, 973;Kuboki et al, 1987]. More recent studies have confirmed that pellicle formation is a fairly rapid process reaching a maximum after approximately 30-60 min depending on the secretion studied [Lamkin et al, 1996].…”

The protective nature of pellicle towards toothpaste abrasion on enamel and dentine

“…1 The thickness of the pellicle generally reaches a plateau after 30-90 min. [2][3][4] The pellicle layer is of great importance since it participates in all the interfacial events taking place at the tooth surface, such as de-and remineralisation, lubrication and bacterial adherence. Indeed, the pellicle can act as a semi-permeable membrane and modulate the demineralisation of enamel.…”