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Rapid prototyping of hydroxyapatite ceramics for bioactive implants

Rapid Prototyping von Hydroxylapatit-Keramik für bioaktive Implantate
: Richter, H.-J.; Baumann, A.; Heinritz, K.; Lenk, R.

Regenerative medicine 4 (2009), No.6, Supplement 2, pp.133
ISSN: 1746-0751
ISSN: 1746-076X
World Conference on Regenerative Medicine (WRM) <2009, Leipzig>
Journal Article, Conference Paper
Fraunhofer IKTS ()
rapid prototyping; 3D-Printing; hydroxyapatite; bioactive implant

Rapid Prototyping (RP) techniques facilitate the manufacturing of components with complex geometry, for example with free form areas, undercuts und hollow structures. With respect to medical application the generative techniques mostly used synonymously with RP techniques allow to fabricate individual, complex shaped implants in a relative short time. The objective of the work was to evaluate the generative techniques 3D-printing (3DP) and Selective Laser Sintering (SLS) concerning their potentials for fabrication of individual and complex shaped bioactive implants based on hydroxyapatite (HAP). At 3DP the ceramic part is generated layer wise from a powder bed. Via a printing head a liquid is added to the powder which is specific solidified by the reaction between powder, liquid and binder. The binder can be contained both in the printing liquid or in the powder bed. A special system powder/ binder/ liquid was developed for 3DP of HAP. With this system HAP-components were generated, for example cuboids with channels (diameter  1 mm) in all three directions in space and fragments of the human mandible as demonstrator parts. After sintering the HAP-components with micro- and macro-porosity are qualified for application as implants. The results verify the performance of 3DP for the fabrication of complex three-dimensional hydroxyapatite structures which can be applied as bioactive implants. This powder printing technique is applicably also to other calciumphosphates (e.g. tri-calciumphosphate). In the case of SLS the conventional sintering step as post-proce ssing after the generation of the component can be omitted. However pure HAP-powder could not be consolidated via direct SLS process. Therefore several approaches to indirect laser sintering of HAP were investigated, such as using of inorganic and organic additives. Also other RP techniques like stereolithography or robocasting offer high potentials with respect to the generation of ceramic implants.