title: The effect of oxalic acid incorporation on the setting time and strength of a glass-ionomer cement.
abstract: Oxalic acid and its metal oxalate salts have been used extensively in dentistry in a range of applications: as desensitisers, in cavity preparation, and as bonding agents. This study investigated the influence of oxalic acid upon the working time, initial setting time, 24-h hardness and compressive strength of a glass-ionomer cement. Conventional glass-ionomer liquids were prepared from polyacrylic acid, tartaric acid, water, and oxalic acid at concentrations of 0-7% w/w. Liquids were dosed into capsules with a commercial glass-ionomer powder, activated and mixed. The resultant pastes were assessed for working time, initial setting time, 24-h hardness and 24-h compressive strength. Liquids containing 0.5-1% oxalic acid lengthened the working time and initial setting time. At concentrations greater than 2%, both working and initial setting times decreased with increasing oxalic acid. Surface hardness values using liquids with 3% and 7% oxalic acid were less hard than the control. Compressive strength was unchanged over the concentrations tested. Oxalic acid may be a useful reaction modifier in glass-ionomer systems. It accelerated the setting reaction without affecting strength, but was limited to low concentrations because of its relatively poor solubility in water.
authors.affiliation: School of Dental Science, University of Melbourne, Parkville, VIC. 3010, Australia.
authors.forename: Leon Hugh
authors.initials: LH
authors.lastname: Prentice
authors.forename: Martin
authors.initials: M
authors.lastname: Tyas
authors.forename: Michael F
authors.initials: MF
authors.lastname: Burrow
mesh_terms: D001696:Biomechanical Phenomena; D019245:Compressive Strength; D005899:Glass Ionomer Cements / Q000737:chemistry*; D008422:Materials Testing; D010070:Oxalates / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D005899:Glass Ionomer Cements; D010070:Oxalates