Bone cements based on ground β-tricalcium phosphate with sufficient compressive strengths and short hardening time

Abstract

In this study, we investigated the hardening processes and compressive strengths of binary and ternary calcium phosphate cements based on ¢-tricalcium phosphate [Ca 3 (PO 4 ) 2 ] (¢-TCP) ground by a mortar grinder. The cements were prepared by adding tetracalcium phosphate [Ca 4 (PO 4 ) 2 O] (TTCP) and/or calcium hydrogenphosphate dihydrate [CaHPO 4 ·2H 2 O] (DCPD) to the ground ¢-TCP, which hardened on mixing with disodium hydrogenphosphate [Na 2 HPO 4 ] aqueous solution. The binary cement ¢-TCP/TTCP with a molar ratio of 2:1 showed a compressive strength of 35 MPa after hardening, which is based on a 1-day acidbase reaction. The ternary cement ¢-TCP/TTCP/DCPD with molar ratios of ¢-TCP (5060%), TTCP (2030%), and DCPD (1420%,) showed early hardening and an adequate compressive strength of 3043 MPa after a 1-day reaction. In particular, the ternary cement with a molar ratio of 3:2:1 (¢-TCP:TTCP:DCPD) showed compressive strengths of 17, 43, and 56 MPa after 1 h in air, and 1 and 7 days' soaking in saline solution, respectively. These ternary cements hardened to give wellconnected acicular apatite crystals. The hardening process involved hydrolysis of the ground ¢-TCP and acidbase reactions of ¢-TCP/TTCP and DCPD/TTCP.

Calcium Phosphate/Etidronate Disodium Biocement: Etidronate, Retarder or Accelerator

“…The final setting is the process of hardening while exposed to the bodily environment and phase transformation reaction based on dissolutionprecipitation [9]. CPCs commonly are classified into two groups based on their hardening reaction: an acid-base reaction or hydrolysis of defined amount of calcium phosphates [10].…”