The effect of strontium oxide in glass-ionomer cements.
The reaction of strontium oxide powder with poly(acrylic acid) has been studied both alone and within glass-ionomer cements. Reaction was found to be slow and the strontium-carboxylate structure was found to be partially covalent in character, as determined by Fourier transform infrared spectroscopy (FTIR). These are similar to the structures formed by calcium in glass-ionomer cements, but are different from typical monomeric strontium carboxylates, which tend to be purely ionic. Strontium oxide powder introduced in two types of glass-ionomer cements, slowed down the setting reaction at both 21 degrees C and 37 degrees C, but at low levels (5 wt %), increased the compressive strength in both cement formulations studied. However, at higher levels, it was found to decrease the compressive strength. This study confirms the view that strontium is a cement-forming ion; but concludes that, except at very low levels, strontium oxide powder does not improve the properties of glass-ionomer cements.
Deb
S
S
Department of Dental Biomaterials, Guy's King's St. Thomas' Dental Institute, Floor 17, Guy's Tower, London Bridge, London SE1 9RT, UK. sanjukta.deb@kcl.ac.uk
Nicholson
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JW