ALPHA-TRICALCIUM PHOSPHATE- AND TETRACALCIUM PHOSPHATE/DICALCIUM PHOSPHATE-BASED DUAL SETTING CEMENTS

摘要

"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 alpha-tricalcium phosphate (alpha-TCP) and tetracalcium phosphate/dicalcium phosphate anhydrous (TTCP/DCPA) conventional cements. N,N'-methylenebisa-crylamide 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 micro-structure of the DS-CPC were compared with those of non-added cements. The DTS increased 22 % for alpha-TCP and 85 % for TTCP/DCPA DS-CPCs by adding 20 wt./voI.-% AA. The HEMA and VP had no positive effect on DTS. The extent of the hydraulic setting reaction for alpha-TCP DS-CPC was only slightly decreased by the addition of 20 wt./vol.-% of AA to the mixing liquid.