Development and Characterization of Water-Based Porous Calcium Phosphate Bone Cements for Peri-Implant Regeneration: An In Situ Study.

BACKGROUND

Calcium phosphate cements (CPCs) are excellent biomaterials for peri-implant bone regeneration but suffer from slow resorption. This study evaluated whether adding carbonate salts improves the in situ porosity and resorption rate of customized CPCs.

METHODS

The control group comprised α-tricalcium phosphate (α-TCP) and phosphoserine (3:1 weight-to-weight ratio). The test group incorporated 3 wt.% anhydrous sodium carbonate (Na2CO3) into the powder. Both were hydrated with water at a liquid-to-powder ratio of 300 μL:1 g. Characterization included micro-computed tomography (μCT), scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), removal torque tests, compression modulus tests, and hardness tests.

RESULTS

μCT and SEM confirmed higher porosity and uniform crystal plates in the test group compared to the dense control group. FTIR-ATR spectra showed a distinct CO2 peak at 2349 cm-1 for the test group, confirming gas entrapment. Mechanically, the control group significantly outperformed the test group in removal torque (71.58 ± 5.56 N/cm vs. 41.37 ± 4.54 N/cm) and compression modulus (1248.01 ± 278.21 MPa vs. 195.42 ± 29.55 MPa). Hardness tests showed increased brittleness in the test group (15.31 ± 1.63 vs. 2.01 ± 1.58).

CONCLUSIONS

Incorporating Na2CO3 successfully induced in situ porosity via gas release but significantly compromised mechanical strength. Further optimization is required to balance porosity and mechanical integrity.