title: Advantages of using glycolic acid as a retardant in a brushite forming cement.
abstract: In this study we have compared the effect of using acetic, glycolic, and citric acids on the brushite cement setting reaction and the properties of the resultant cement. The cement solid phase was made by mixing beta-tricalcium phosphate (beta-TCP), monocalcium dihydrogen phosphate anhydrate (MCPA), and sodium pyrophosphate, whereas the cement liquid phase consisted of aqueous solutions of carboxy acids at concentrations ranging from 0.5 to 3.5M. Cements were prepared by mixing the solid phase with the liquid phase to form a workable paste. The cement setting time was longer for glycolic and citric acids. The best mechanical properties in dry environments were obtained using glycolic and citric acid liquid phases. In a wet environment at 37 degrees C, the cement set with glycolic acid was the strongest one. Brushite cement diametral tensile strength seems to be affected by the calcium-carboxyl phase produced in the setting reaction. The acceptable setting time and mechanical properties of cements set in glycolic acid solutions are attributed to the additional hydrophilic groups in the carboxylic acid and the low solubility in water of the calcium salt produced in the reaction. Moreover, at high concentrations, carboxylic acids add chemically to the cement matrix becoming reactants themselves.
authors.affiliation: Departamento de Quimica Física II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza Ramon y Cajal, 28040 Madrid, Spain. fdamimim@farm.ucm.es
authors.forename: Faleh Tamimi
authors.initials: FT
authors.lastname: Mariño
authors.forename: Jesús
authors.initials: J
authors.lastname: Torres
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hamdan
authors.forename: Carmen Rueda
authors.initials: CR
authors.lastname: Rodríguez
authors.forename: Enrique López
authors.initials: EL
authors.lastname: Cabarcos
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D001843:Bone Cements / Q000138:chemical synthesis* / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D006016:Glycolates / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; D006016:Glycolates; C485817:beta-tricalcium phosphate; C031149:glycolic acid; C494366:calcium phosphate, dibasic, dihydrate; D019342:Acetic Acid