Investigation of Changes in Phases and Properties of a TTCP/DCPA/CSH Cement Immersed in Hanks’ Solution

Abstract

Investigated in this study are the changes in structure and properties of a tetracalcium phosphate/dicalcium phosphate anhydrous/calcium sulfate hemihydrate (TTCP/DCPA/CSH) cement immersed in Hanks' solution. Experimental results show that the phase transition involving the hydration of CSH and formation of calcium sulfate dihydrate (CSD) continues up to 7 d of immersion. The phase transition from TTCP/ DCPA to hydroxyapatite (HA) is substantially completed after 14 d; after that, both CSH and CSD phase largely diminished, whereas HA becomes and remains to be the only dominant phase throughout 42 d of immersion. A maximum compressive strength is reached; after that, the cement gradually decreases in strength. After 42 d, its CS value is down to 8 MPa. The long-term pH value of the Hanks' solution wherein the cement is immersed remains in the range between 5.4 and 7.0. The cytotoxicity test reveals that the viability value of the cells incubated with conditioned medium of cement extraction is 85% that of Al 2 O 3 control and 84% that of blank medium for an extraction ratio of 0.2; and 90% that of Al 2 O 3 control and 93% that of blank medium for an extraction ratio of 0.1.

Self-Setting Calcium Orthophosphate Formulations

“…The list of possible additives includes (but is not limited to) the following cations: Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , Zn 2+ , H + and anions: PO 4 3− , HPO 4 2− , H 2 PO 4 − , P 2 O 7 4− , CO 3 2− , HCO 3 − , SO 4 2− , HSO 4 − , Cl − , OH − , F − , silicates [ 46 ]. Therefore, mixed-type self-setting formulations consisting of calcium orthophosphates and other calcium salts, such as calcium sulfate [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ], calcium pyrophosphate [ 64 , 65 , 66 ], calcium polyphosphates [ 67 , 68 ], calcium carbonates [ 16 , 26 , 28 , 30 , 50 , 69 , 70 , 71 ], calcium oxide [ 72 , 73 , 74 , 75 , 76 , 77 ], calcium hydroxide [ 78 , 79 , 80 ], calcium aluminates [ 43 , 81 , 82 ], calcium silicates [ 83 , 84 , 85 , 86 , 87 , 88 , 89 ], etc ., are available. In addition, other chemicals such as Sr-containing compounds [ 19 , 90 , 91 , 92 , ...…”

Enhanced Stability of Calcium Sulfate Scaffolds with 45S5 Bioglass for Bone Repair

“…Calcium sulfate (CaSO 4 ) has been used extensively as bone defects fillers on account of the superb biocompatibility and osteoconductive, which can degrade and be resorbed completely by surrounding bone tissue [ 9 , 10 , 11 , 12 ]. However, CaSO 4 fails to provide effective support for the defect site in the process of bone repair, due to its fast disintegration and poor mechanical strength [ 13 ]. In addition, CaSO 4 demonstrates no bioactivity and is not able to form a chemical bond with the surrounding tissue [ 14 , 15 ].…”

Tetracalcium Phosphate/Monetite/Calcium Sulfate Hemihdrate Biocement Powder Mixtures Prepared by the One-Step Synthesis for Preparation of Nanocrystalline Hydroxyapatite Biocement-Properties and In Vitro Evaluation

“…The influence of CS on the change in cement porosity after an addition of coarse rod-like CSD particles (10–25 wt.%) to αTCP cement showed a porous microstructure with prolonged pores being obtained after dissolving CSD [ 25 ]. About 30% porosity was achieved in TTCPM/20 wt.% CSH cements after 7 days of setting in Hank’s solution, but no mention of the L/P ratio is given in [ 22 ] despite the fact that it strongly affects the porosity [ 42 ]. On the other hand, about 46% porosity was measured in TTCPM cement with P/L = 3 [ 43 ], which was a lesser value than that used in C or CAS5 cements due to the lower addition of liquid components.…”

“…In the case of setting time, small variations in setting time (ST) of fast setting αTCP cement with a change of H 2 SO 4 concentration (up to 0.33 M) in a liquid component have been revealed [ 19 ], contrary to the strong effect of the liquid/powder (L/P) ratio found in CPC/CSH cement pastes, which clearly indicates the need to optimize this parameter [ 20 ]. Enhanced injectability was measured in TTCPM/CSH cement mixtures with short setting times and showed improved mechanical properties compared to brushite/CSH cements [ 21 , 22 ]. The TCP/CSH cement mixture showed a weak CS (about 5 MPa) with the formation of brushite and calcium sulfate dihydrate (CSD) after setting with NaH 2 PO 4 solution in a mold [ 23 ], while, in the case of TTCPM/CSD cement (even with 50 wt.% of CSD), a rapid transformation of cement components to hydroxyapatite was identified in a short time [ 24 ].…”