Alpha-tricalcium phosphate- and tetracalcium phosphate/dicalcium phosphate-based dual setting

Abstract

“Dual-setting” calcium phosphate cements (DS-CPCs), characterized by a polymerization reaction that proceeds along with the conventional hydraulic setting, were prepared and studied. Acrylamide (AA), 2-hydroxyethyl methacrylate (HEMA), and N-vinyl-2-pyrrolydone (VP) in 5, 10, and 20 wt./vol.-% were added to the liquid of α- tricalcium phosphate (α-TCP) and tetracalcium phosphate/dicalcium phosphate anhydrous (TTCP/ DCPA) conventional cements. N,N’-methylenebisacrylamide was used as cross linking agent. N,N,N´,N´-tetramethylethylendiamine in the liquid, and ammonium persulfate in the powder, were employed as polymerization catalyst and initiator, respectively. Diametral tensile strength (DTS), setting time, phase composition, conversion rate, and microstructure of the DS-CPC were compared with those of non-added cements. The DTS increased 22 % for α-TCP and 85 % for TTCP/DCPA DS-CPCs by adding 20 wt./vol.-% AA. The HEMA and VP had no positive effect on DTS. The extent of the hydraulic setting reaction for α-TCP DS-CPC was only slightly decreased by the addition of 20 wt./vol.-% of AA to the mixing liquid.