Effect of Sodium Phosphate and Cellulose Ethers on MgO/SiO2 Cements for the 3D Printing of Forsterite Bioceramics

Magnesium silicate ceramics are promising materials for bone tissue regeneration and can be prepared through 3D printing of magnesium oxide/silica (MgO/SiO2) cement pastes followed by calcination. Despite the growing interest in these formulations, additive manufacturing technology has only recently been explored for these cements, and the effects of admixtures and additives on such printing inks remain largely unexplored. In this study, we prepared various MgO/SiO2 cement formulations with differing amounts of sodium orthophosphate, a setting retarder, and cellulose ethers, used as rheo-modifiers. The samples’ setting properties were investigated, and printing parameters were properly adjusted. The most promising formulations were then 3D printed and calcined to obtain forsterite bioceramics, which were further characterized using confocal Raman microscopy, scanning electron microscopy, atomic force microscopy, gas porosimetry, and compressive strength tests. Our results revealed that the cellulose derivatives influence the printability of the MgO/SiO2 formulations without affecting the hardening time, which can be adjusted by the addition of sodium phosphate. The use of fine-tuned formulations allowed for the preparation of 3D-printed forsterite bioceramics, potentially suitable for biological applications as cancellous bone scaffolds.