Publication: Impact of acidic calcium phosphate solution concentration on the setting ability of β-tricalcium phosphate (β-tcp) and hydroxyapatite (HAP) porous granular cement
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Date
2025-08-07
Authors
Yeoh, Jing Yi
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Abstract
This study investigates the effect of acidic calcium phosphate solution concentration containing citric acid on the setting ability of β-tricalcium phosphate and hydroxyapatite porous granular cements under physiological conditions as the materials can affect the properties in acidic condition. β-TCP and HAp granules were fabricated with calcium carbonate and dicalcium phosphate dihydrate at Ca/P ratios of 1.5 and 1.67 and followed by sintering at 1100°C with a heating rate of 5℃/min on 6 hours. Then, the acidic calcium phosphate solution was added with different concentration of citric acid (0.01, 0.10 and 1.00 mol/L) that act as inhibitor. The setting reaction was conducted under physiological conditions and setting reaction at 10 and 30 minutes. Characterization of X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), porosity and compressive strength were carried out. The study aims the effect of acidic calcium phosphate solution containing different oncentrations of citric acid on setting ability, porosity, phase transformation and compressive strength at 10 minutes and 30 minutes. At 10 minutes, β-TCP granular cement with 0.10 mol/L citric acid has achieved the highest compressive strength (0.45 MPa) due to effective DCPD crystal interlocking between granules. While HAp granular cement was unsuccessful to set at all concentrations of citric acid. After 30 minutes, β-TCP granular cement with 1.00
mol/L citric acid had highest compressive strength (0.26 MPa) with highest porosity. β β while HAp granular cement partially set for 1.00 mol/L citric acid with lowest compressive strength (0.04 MPa) that indicate strong inhibition of DCPD crystallization by citric acid. Overall, β-TCP granular cement set faster and effectively than HAp granular cement as their higher solubility and reactivity in acidic environments. Also, the setting times clinically acceptable for surgical use, while HAp requires further optimization.