MAS-NMR spectroscopy studies in the setting reaction of glass ionomer cements

Artemis Stamboulis, S Matsuya, RG Hill, RV Law, K Udoh, M Nakagawa, Y Matsuya

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24 Citations (Scopus)


OBJECTIVES: The main objective is the characterisation of the setting reaction in glass ionomer cements based on experimental ionomer glasses with different fluorine content and a commercial glass ionomer cement liquid by using 13C CP/MAS-NMR, 29Si, 27Al and 31P MAS-NMR spectroscopy in order to receive information specifically about the cross-linking process. METHODS: Different fluorine containing glass compositions based on 4.5SiO2-3Al2O3-1.5P2O5-(5-z)CaO-zCaF(2) where z=0-3, were mixed with a commercially available polymer liquid to form glass ionomer cements. The cements were subjected to 27Al, 13C CP/MAS, 29Si, and 31P MAS-NMR analysis. RESULTS: The 27Al spectra showed clearly the formation of six-fold coordinate Al(VI), that may crosslink the carboxyl groups in the poly-acid molecules. A shift towards to more positive values of the carboxyl peak in the 13C CP/MAS-NMR spectra showed clearly the proton dissociation of the carboxyl groups. A shift towards more negative values was observed in the 29Si MAS-NMR spectra, suggesting formation of hydrated silica gel and consequently formation of additional Si-O-Si bonds. 31P MAS-NMR spectra also reflected changes in the coordination state around a PO4(3-) tetrahedron. Increasing the fluorine content of the glasses resulted generally in increased reactivity during setting, due to promoting cross-linking and repolymerisation of the silicate phase, followed by clear changes in the MAS-NMR spectra. CONCLUSIONS: The cross-linking process during the setting reaction of glass ionomer cements can be followed by MAS-NMR spectroscopy observing the conversion of Al(IV) to Al(VI). The acid base setting reaction is completed in 1 day and no further significant changes in the MAS-NMR spectra can be observed. Further study is required in order to understand the role of phosphorus.
Original languageEnglish
Pages (from-to)574-581
Number of pages8
JournalJournal of Dentistry
Early online date28 Feb 2006
Publication statusPublished - Sept 2006
EventProceedings of the 2nd European Glass Ionomer Conference, May 2004 - Coventry, United Kingdom
Duration: 1 May 200431 May 2004


  • fluorine containing glasses
  • cross-linking
  • glass ionomer cements
  • setting reaction


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