3D Powder Printing of β‐Tricalcium Phosphate Ceramics Using Different Strategies

b -Tricalcium phosphate ( b -TCP) is an osteoconductive and resorbable bone substitute material which is either applied as granules or a sintered monolithic body with defined shape. [1,2] Fabrication of the latter is done by slip casting, [3] isostatic pressing [4] and more recently by using rapid prototyping (RP) techniques. [5,6] Rapid prototyping is a technology where a near net shape three dimensional component is created by the layer by layer deposition of a material. One of the major advantages of RP methods, when compared with traditional ceramic processing methods, is that they allow the fabrication of patient specific implants from computer tomography (CT) data. [6] This is beneficial especially for large-size or geometrically complex defects since it is possible to produce implants with a high dimensional accuracy which guarantees optimal implant integration into the defect. Various RP techniques have been described in literature for the fabrication of calcium phosphate bioceramics, these methods can be divided into either direct or indirect techniques. The latter typically use wax or polymer structures which are produced by stereolithography and then infiltrated with a calcium phosphate slurry. After the slurry has hardened the inverse wax / polymer pattern is either dissolved at room temperature [7] or burned out during heat treatment [8,9] to leave the desired pore geometry. Direct RP techniques for bioceramic fabrication include selective laser sintering of polymer-modified ceramic powders, [10] computer aided design (CAD) guided fused deposition modelling [11] or 3D powder printing. [6] The latter uses organic or inorganic binders which are sprayed onto a flat powder bed and locally binds the ceramic particles due to adhesive forces or a hydraulic cement setting