Fast Ceramics Production (FCP) is a proprietary three-dimensional stereo lithography technology that is applied to ceramics to create patient-specific or volume production ceramic bone substitutes and implants. The process, developed by 3DCeram (Colorado Springs, CO), brings together materials and PhD-level process experts’ skills for the rapid and volume manufacturing of, for example, ceramic tibial osteotomy wedges, intervertebral cages (see Fig. 1), and cranial or jawbone implants.
Ceramic Bone Substitutes
Based on laser-computer-driven stereo lithography applied to ceramics, FCP technology produces substitutes in successive layers that are polymerized from a paste made of photosensitive resin and calcium phosphates. Calcium phosphates, such as hydroxyapatite or tricalcium phosphates, are the synthetic materials most similar to the chemical composition of human bone. They are known for their osteoconductive properties, especially when the pore size distribution and interconnections are well designed and exactly reproduced. After about 10 years of research and industrialization, 3DCeram is using proprietary resin formulations as well as laser and associated machinery equipments to create complex bone implants.
After stereolithography, the “blank” obtained resembles a cake including some unpolymerized resin and a scaffold made of a high content of ceramics powder and some polymerized resin. It is then cleaned and heat-treated in order to eliminate the residual unpolymerized and polymerized resin. After a final high temperature sintering operation, the scaffold, or ceramics bone substitute, is completely densified around the digitally designed recesses or porosity distribution, thereby attaining an exceptional biocompatibility and mechanical strength. This manufacturing process does not break the computer design chain at any point, from the CAD file creation to the finished bone substitute. This is critical for achieving the responsive and cost-efficient solution expected by medical professionals.
FCP technology enables the precise control of the location and geometry of the ceramic substitutes’ pores, unlike implants that are made porous by adding organic foams. FCP porosity is built in three dimensions; the fully interconnected pores exhibit a diameter that is constant and ensured exactly per the initial computer file requirements. Bone remodeling, or osteointegration, is promoted, while the risk of rejection is reduced. This also increases the substitutes’ compression mechanical strength by a factor of three to five in comparison to conventional porous structures. FCP can therefore improve patient comfort and greatly reduce the risk of post-operation inflammation caused by micro debris created when handling and positioning the implant.
Using this technology, a process called BioCranium® was developed for the manufacturing of patient-specific bio-ceramic cranial or jawbone implants (see Fig. 2). The surgeon controls the most critical aspects of the surgical process by adjusting the bone substitute design to the pathology of the patient. The model of the 3D digital bone defect to be repaired is created directly from the patient’s pre-surgery scan and in accordance with the surgeon’s instructions. The surgeon analyzes and decides on the right shape, location, and structure of the ceramic bone substitute’s porous areas that will favor the prosthesis’s osteointegration. The implant, accurate to four-thousandth of an inch and produced in a very short time, is suited to the morphology of the patient.
To date, the FCP process for manufacturing ceramic bone substitutes and implants has been developed and successfully implemented with the help of recognized medical professionals and surgeons in France. FDA authorizations are pending.
The FCP process has also been used to develop several industrial applications where the necessary ceramics component design complexity cannot be achieved (or achieved with extreme difficulty and cost with conventional ceramics manufacturing processes like die pressing, injection molding, and green or hard machining).
Design features like inner cavities, apertures from all three directions, or negative recesses can be produced. The FCP process lends itself nicely to the rapid manufacturing of prototypes or low-volume production since no mold or tooling is necessary. Only an STL or IGES component design file is needed.
3DCeram has been also industrializing the process so that volume production exceeding 50,000 to 100,000 units per year is now cost-effective. Typical materials include high-grade alumina, zirconia, aluminum nitride, and others including, customers’ own powders, after a development phase. Current maximum component size is approaching 20". FCP-processed components exhibit properties identical to the volume production quality achieved with more conventional ceramics manufacturing processes.
For example, such applications are high-pattern-density microwave filters or resonators, parts for watches and other luxury items, and mechanical relay frames (see Fig. 3).