New aspects of the setting of glass-ionomer cements.
For many years, glass-ionomer cements have been described as setting by the formation of a poly(acrylate) matrix. Recent research has suggested that a second reaction may be involved, namely, the formation of a silica matrix. So that this hypothesis could be tested, non-polymer cements, based on an ionomer glass plus acetic acid, were prepared and stored for up to six months. They were insoluble in water, and their compressive strength was found to increase rapidly over the period of storage. By contrast, the product of the reaction between ZnO and acetic acid was soluble in water. These results support the idea that there is a secondary setting reaction in glass ionomers and suggest that it is responsible for the increase in strength observed.
Materials Technology Group, Laboratory of the Government Chemist, Teddington, Middlesex, United Kingdom.
E A
EA
Wasson
J W
JW
Nicholson
D000085:Acetates / Q000737:chemistry; D019342:Acetic Acid; D000704:Analysis of Variance; D005898:Glass / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000138:chemical synthesis* / Q000737:chemistry; D006244:Hardness; D012822:Silicon Dioxide / Q000737:chemistry; D013055:Spectrophotometry, Infrared
D000085:Acetates; D005899:Glass Ionomer Cements; D012822:Silicon Dioxide; D019342:Acetic Acid