Calcium phosphate grafts produced by rapid prototyping based on laser cladding

Rapid prototyping based on laser cladding by powder injection has been used to produce calcium phosphate three-dimensional grafts without using molds. Precursor material comprising of hydroxyapatite (HA) powder was irradiated by means of an infrared Nd:YAG laser. The processing parameters and the thermal history of the processed material have been assessed and the process has been optimized to obtain solid parts. Processing by laser cladding lead to complete dehydroxylation of the precursor HA, the obtained microstructure is composed by an alpha-tricalcium phosphate (α-TCP) matrix with nucleated tetracalcium phosphate (TTCP) grains, in coexistence with oxyapatite and amorphous calcium phosphate. The produced bioceramic grafts were observed to be bioactive, leading to calcium-deficient hydroxyapatite precipitation and promoting pre-osteoblastic cell attachment and proliferation during “in vitro” cell culture test.