The interaction of zinc oxide-based dental cements with aqueous solutions of potassium fluoride
Pawluk, K., Booth, S.E., Coleman, N.J. and Nicholson, J.W. (2008) The interaction of zinc oxide-based dental cements with aqueous solutions of potassium fluoride. Journal of Materials Science: Materials in Medicine, 19 (9). pp. 3035-3039. ISSN 0957-4530 (Print), 1573-4838 (Online) (doi:10.1007/s10856-008-3443-0)Full text not available from this repository.
The ability of zinc oxide-based dental cements (zinc phosphate and zinc polycarboxylate) to take up fluoride from aqueous solution has been studied. Only zinc phosphate cement was found to take up any measurable fluoride after 5 h exposure to the solutions. The zinc oxide filler of the zinc phosphate also failed to take up fluoride from solution. The key interaction for this uptake was thus shown to involve the phosphate groups of the set cement. However, whether this took the form of phosphate/fluoride exchange, or the formation of oxyfluoro-phosphate groups was not clear. Fluoride uptake followed radicaltime kinetics for about 2 h in some cases, but was generally better modelled by the Elovich equation, dq(t)/dt = alpha exp(-beta q(t)). Values for alpha varied from 3.80 to 2.48 x 10(4), and for beta from 7.19 x 10(-3) to 0.1946, though only beta showed any sort of trend, becoming smaller with increasing fluoride concentration. Fluoride was released from the zinc phosphate cements in processes that were diffusion based up to M(t)/M(infinity) of about 0.4. No further release occurred when specimens were placed in fresh volumes of deionised water. Only a fraction of the fluoride taken up was re-released, demonstrating that most of the fluoride taken up becomes irreversibly bound within the cement.
|Uncontrolled Keywords:||glass-ionomer cements, acidic conditions, release, kinetics, sorption, ions, dissolution|
|Subjects:||R Medicine > RK Dentistry|
|School / Department / Research Groups:||School of Science
Faculty of Engineering & Science > School of Science
School of Science > Department of Pharmaceutical, Chemical & Environmental Sciences
Faculty of Engineering & Science > School of Science > Department of Pharmaceutical, Chemical & Environmental Sciences
|Last Modified:||19 Jan 2015 17:08|
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