Physical characterization and in vitro evaluation of 3D printed hydroxyapatite, tricalcium phosphate, zirconia, alumina, and SiAlON structures made by lithographic ceramic manufacturing

In this study, lithographic ceramic manufacturing was used to create solid chips out of hydroxyapatite, tricalcium phosphate, zirconia, alumina, and SiAlON ceramic. X-ray powder diffraction of each material confirmed that the chips were crystalline, with little amorphous character that could result from remaining polymeric binder, and were composed entirely out of the ceramic feedstock. Surface morphologies and roughnesses were characterized using atomic force microscopy. Human bone marrow stem cells cultured with osteogenic supplements on each material type expressed alkaline phosphatase levels, an early marker of osteogenic differentiation, on par with cells cultured on a glass control. However, cells cultured on the tricalcium phosphate-containing material expressed lower levels of ALP suggesting that osteoinduction was impaired on this material. Further analyses should be conducted with these materials to identify underlying issues of the combination of material and analysis method.