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  • 1
    Electronic Resource
    Electronic Resource
    Adhesion of stainable, calcium–rich deposits on substrata with different surface free energies (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 16 (1989), S. 0 
    Details
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract Calculus plays an important role in chronic inflammatory periodontal disease and tooth loss. Patients can suffer from calculus formation despite good oral hygiene. The strength of adhesion between calculus and the enamel surface, though not determinant for the formation of calculus itself, determines whether calculus remains on the teeth during eating and toothbrushing. In this study, the amount and the strength of adhesion of calcium-rich deposits formed in vivo on different materials are related to substrate surface free energies (sfe). In 4 beagle dogs, fenestrated crowns were made on the upper fourth premolars. Smooth facings of glass (sfe 120 mJ·m-2), polished bovine enamel (sfe 85 mJ·m-2), polymethylmethacrylate (PMMA sfe 56 mJ·m-2) and polytetafluorethylene (PTFE sfe 20 mJ·m-2) were inserted in the crowns for 1, 3, 7, 14 or 28 days. The amount of deposit was evaluated both gravimetrically and planimetrically using Alizarin Red S for staining. Adhesion of calcium-rich deposits was evaluated planimetrically by studying their removal in a brushing machine. Dry weight increased linearly with time (approximately 0.18 mg·cm-2 per day) and was slightly less on PTFE than on the other materials. After 1 to 3 days, staining already revealed a 100% coverage by calcium-rich deposits. The number of strokes required to reduce the planimetric scores by 63% was extremely small on PTFE and PMMA and related with substrate surface free energies. This study shows that a possible way to reduce calculus formation in vivo is to decrease the surface free energy of the enamel using appropriate surfactants in, e.g., toothpastes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-051X.1989.tb01666.x
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  • 2
    Electronic Resource
    Electronic Resource
    Adsorption of quaternary ammonium chlorides with various hydrocarbon chain lengths to glass (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 711-714 
    Details
    ISSN: 1435-1536
    Keywords: Glass ; quaternaryammonium chlorides ; contact angle ; Surface free Energy ; Ellipsometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Contact angles, measured with various liquids, have been employed to calculate the surface free energies of glass after adsorption of quaternary ammonium chlorides with a variable hydrocarbon chain length 8≤n≤16. The thickness of the adsorbed layers has been determined ellipsometrically. A clear relation is observed between the measured parameters and the hydrocarbon chain lengthn, if only the extremesn=8 andn=16 are considered. Surface free energies decrease from 138 erg.cm−2 for clean glass to 101 and 64 erg.cm−2 forn=8 andn=16, respectively, at the highest concentration tested (7.5 mM). The adsorbed layer thickness of C8 amounts to approximately 50 % of the thickness observed for C16. No clear relation between the measured parameters is observed for the intermediate hydrocarbon chain lengths, which presumably reflects the many configurations possible in these adsorbed layers. It is envisaged that adsorption of C8 as well as C16 is restricted to a monolayer, which is completed at approximately 2 mM. In the case of C8 electrostatic repulsion between the polar headgroups will inhibit further adsorption, whereas in the case of C16 the van der Waals attraction from the adsorbed layer and the glass will probably not be sufficient to stimulate further adsorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425033
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  • 3
    Electronic Resource
    Electronic Resource
    Amount and surface structure of albumin adsorbed to solid substrata with different wettabilities in a parallel plate flow cell (1990)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 24 (1990), S. 1599-1614 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In this article we studied the adsorption of serum albumin to substrata with a broad range of wettabilities from solutions with protein concentrations between 0.03 and 3.00 mg · mL-1 in a parallel-plate flow cell. Wall shear rates were varied between 20 and 2000 s-1. The amount of albumin adsorbed in a stationary state was always highest on PTFE, the most hydrophobic material employed and decreased with increasing wettability of the substrata. Increasing stationary amounts of adsorbed albumin were observed with increasing wall shear rates at the lowest protein concentration. Inverse observations were made at the highest protein concentration. Transmission electron micrographs of replicas from the albumin-coated substrata showed that proteins were mostly adsorbed in islandlike structures on the hydrophobic substrata. The tendency to form islandlike structures was shear rate- and concentration-dependent and disappeared gradually going to more hydrophilic substrata. On glass, the most hydrophilic material employed, a homogeneous, well distributed, fine knotted, reticulated structure was found. In conclusion, this study demonstrates that both the amount of adsorbed albumin as well as the surface structure of the adsorbed proteins are regulated by the substratum wettability. This observation may well account for the fact that substratum properties can be transferred by an adsorbed protein film to the interface with adhering cells or microorganisms.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820241205
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