Additive manufacturing of cardiovascular CoCr stents by selective laser melting

Abstract

• SLM was used to produce CoCr prototype stents with PW laser emission. • A prototype stent mesh employing design rules for SLM was proposed. • Concentric scanning improved geometrical fidelity compared to hatching. • Prototype stents were similar in surface roughness and microhardness compared to macro SLM components. • The efficacy of electrochemical polishing depended on the correct selection of the SLM scan strategy.

A Review of Metal Fabricated with Laser‐ and Powder‐Bed Based Additive Manufacturing Techniques: Process, Nomenclature, Materials, Achievable Properties, and its Utilization in the Medical Sector

“…[289] In the case of dental restorations, such as dental bridges and frameworks, the current state-of-the-art involves the polishing of milled or cast restorations by hand, since the requirements on the surface quality cannot be achieved in the forming process, for example, in investment casting or via PBF. [291] In addition, the combination of CT-scanning with AM has been shown to be very promising for the fast and efficient supply of restorations, offering perfect compatibility of the implant due to customized design. The geometrical complexity and delicate structure of dental restorations, such as bridges and frameworks, are very attractive for the fabrication via AM.…”

“…[290] A recent investigation on CoCr stents came to the conclusion that the productivity of their fabrication is higher when fabricated via SLM as opposed to the conventional schemes, even though the surface finish has to be improved in a subsequent step. [291] In addition, the combination of CT-scanning with AM has been shown to be very promising for the fast and efficient supply of restorations, offering perfect compatibility of the implant due to customized design. [292,293] Considering implants, where the key criterions are to have a compatible contact between the implant and the human body, the possibilities AM offers have been proven to be beneficial and lower the likelihood of implant rejections.…”

“…Removal of the attached powder particles and controllable surface roughness on highly porous strut structures [307] Pore geometry on open porous structures Growth of human periosteum-derived cells in dependency to the pore shape and size; optimization of the bone ingrowth behavior [298] Functionally graded bone implants Designed compressive characteristics of femoral stems with a porous core and a beaded surface morphology for cementless fixation [308] Functionally graded dental implants Implants with a gradient porosity from the inner core to the outer surface [18] Feasibility study on micro-actuators Micro actuators for cochlear implants; treatment for deaf people suffering from damages in the inner ear [309] Clinical study on the bone ingrowth behavior Various bone implants were fabricated with SLM and EBM and implanted in goats and sheep [310,311] Clinical study on the survival rate of dental mini implants 231 dental mini implants were placed in 62 patients, the survival rate after 4 years was 96.9% [312] Custom made dental root implant Congruent (root-analogue) implants for perfect fit, geometrical data acquired via CT scan and subsequent 3D reconstruction; faulty tooth directly replaced after removal [294,313,314] Custom made dental blade implant Non-conventional treatment; proven solution for patients which cannot be treated with regular root-form implants due to atrophied posterior mandible [315] Custom made sternum and rib cage Reconstruction of a partial rib-cage for a patient suffering from chest wall sarcoma [316] Custom made heel implant Reconstruction of the heel bone for a patient with cancer of the calcaneus [317] Custom made hip implant Production of a polymer prototype of the patients hip bone based on CT-data; designing and fabrication a polymer hip implant as intermediate step, fabrication of a Ti6Al4V hip implant based on the optimized geometry, implant was implanted into an patient and good results were reported [293] Artificial beak for a rare crane bird Reconstruction of the upper beak of a Grus japonensis bird, iterative optimizations undertaken by utilizing polymer printing; final design of the prosthetic beak fabricated with SLM and successfully installed in a surgery [318] Fabrication of cardiovascular stents via SLM SLM coupled with conventional electrochemical polishing was found as a suitable manufacturing approach, outperforming the conventional stent manufacturing scheme [291] Osseointegration in EBM fabricated mesh and foam scaffolds Study the osseointegration and seeding efficiency based on the scaffold design; trial study on a pelvic bone implant (custom-made periacetabular phrosthesis) for a tumor patient [319] Acetabular shells Fabrication of acetabular shells ...…”

Stent’s Manufacturing Field: Past, Present, and Future Prospects

“…AM refers to processes used to create a 3D object in which layers of material are formed under computer control. The use of this technology for stent manufacture is recent [57][58][59][60][61][62][63][64] and could be a really interesting method to produce stent. Mainly, there are four different AM technologies in the stent field.…”

“…Their approach presented a new and interesting method to produce stents based on polymers in less than 2 min ( Figure 5). Demir and Previtali [60] produced CoCr stent through SLM as an alternative method to the conventional manufacturing cycle. Results showed that SLM can be considered as a substitute operation to laser micro-cutting.…”