Influence of fluoride-detergent combinations on the visco-elasticity of adsorbed salivary protein films.
The visco-elasticity of salivary-protein films is related to mouthfeel, lubrication, biofilm formation, and protection against erosion and is influenced by the adsorption of toothpaste components. The thickness and the visco-elasticity of hydrated films (determined using a quartz crystal microbalance) of 2-h-old in vitro-adsorbed salivary-protein films were 43.5 nm and 9.4 MHz, respectively, whereas the dehydrated thickness, measured using X-ray photoelectron spectroscopy, was 2.4 nm. Treatment with toothpaste slurries decreased the thickness of the film, depending on the fluoride-detergent combination involved. Secondary exposure to saliva resulted in a regained thickness of the film to a level similar to its original thickness; however, no association was found between the thickness of hydrated and dehydrated films, indicating differences in film structure. Treatment with stannous fluoride/sodium lauryl sulphate (SnF(2)/SLS)-containing toothpaste slurries yielded a strong, immediate two-fold increase in characteristic film frequency (f(c)) with respect to untreated films, indicating cross-linking in adsorbed salivary-protein films by Sn(2+) that was absent when SLS was replaced with sodium hexametaphosphate (NaHMP). Secondary exposure to saliva of films treated with SnF(2) caused a strong, six-fold increase in f(c) compared with primary salivary-protein films, regardless of whether SLS or NaHMP was the detergent. This suggests that ionized stannous is not directly available for cross-linking in combination with highly negatively charged NaHMP, but becomes slowly available after initial treatment to cause cross-linking during secondary exposure to saliva.
Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Groningen, the Netherlands.
Deepak H
DH
Veeregowda
Henny C
HC
van der Mei
Henk J
HJ
Busscher
Prashant K
PK
Sharma
D000327:Adsorption; D000818:Animals; D002417:Cattle; D003432:Cross-Linking Reagents; D044622:Dental Pellicle / Q000737:chemistry* / Q000187:drug effects*; D003902:Detergents / Q000737:chemistry / Q000494:pharmacology*; D004338:Drug Combinations; D004548:Elasticity / Q000187:drug effects; D005260:Female; D005459:Fluorides / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010710:Phosphates / Q000494:pharmacology; D056951:Photoelectron Spectroscopy; D058525:Quartz Crystal Microbalance Techniques; D012471:Salivary Proteins and Peptides / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology; D014002:Tin Fluorides / Q000494:pharmacology; D014100:Toothpastes / Q000737:chemistry / Q000494:pharmacology*; D014783:Viscosity / Q000187:drug effects; D014867:Water
D003432:Cross-Linking Reagents; D003902:Detergents; D004338:Drug Combinations; D010710:Phosphates; D012471:Salivary Proteins and Peptides; D014002:Tin Fluorides; D014100:Toothpastes; D014867:Water; D012967:Sodium Dodecyl Sulfate; D012969:Sodium Fluoride; C009285:sodium polymetaphosphate; D005459:Fluorides