Biomaterials

The materials that can be used in the 3D printing technique can be organic or inorganic. The inorganic inks could be categorized into metals, ceramics and glass-ceramics, and the organic ones into thermoplastic and hydrogels [20]. Titanium, cobalt-chrome, stainless steel and magnesium are some of the metallic biomaterials used. Calcium phosphates like hydroxyapatite, brushite and monetite belong in ceramics. In the glass-ceramics category, bioglass, such as silicon dioxide, calcium oxide, sodium oxide and phosphorous pentoxide, is included. As for the organic category, poly-lactic acid (PLA), polyglycolic acid (PGA) and polycaprolactone (PCL) are some of the most frequently used thermoplastics. The category of hydrogels can be divided into synthetic (poly ethylene glycol—PEG; poly vinyl alcohol— PVA; or poly acrylic acid—PAA), semi-synthetic (like derivates of hyaluronic acid, elastin and collagen) and natural (e.g., polynucleotides, polysaccharides and polypeptides) [20].
