Wettability and physicochemical characteristics of biphasic calcium phosphate mixtures depending on the ratio of hydroxyapatite and β-tricalcium phosphate

Alloplastic grafts are synthetic, inorganic, biocompatible, and bioactive bone substitutes which promote osteoconduction, including hydroxyapatite (HA), β-tricalcium phosphate (β-TCP), and biphasic calcium phosphate (BCP). A mixture of HA and β-TCP has been widely used as an alloplastic graft in dental applications, for its ability to modify the biodegradation rate by changing the HA/β-TCP ratio. Wettability is widely known to be a significant and favorable factor for bone grafting materials as it allows immediate exposition to vascular invasion. Herein, a series of xHA-(100–x)β-TCP (x = 0, 10, 30, 50, 70, 90, and 100 wt.%) samples were prepared and their wettability and physicochemical properties were examined. The chemical compositions and structural properties of the samples were studied using X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. The pH of the samples in Dulbecco’s modified Eagle’s medium (DMEM) solvent increased from 7.55 to 8.55–9.28, implying the dissolution of the samples and Ca²⁺ release. Contact angle of deionized water on the samples decreased gradually with increasing β-TCP content. HA exhibited low wetting while β-TCP exhibited complete wetting. Therefore, in terms of wettability, good osteogenic ability and workability for a bone grafting material can be achieved by including β-TCP.