Hello Jun Yue,

There are a few technologies regarding 3D Printing and the correct name would be Additive Manufacturing (AM) formerly also known as Rapid Prototyping (RP). In AM there is 3D Printing (inkjet basis), there is FDM (fused deposition modelling), SLA (stereolitography/optical process) and SLS (selective laser sintering), there are a few more technologies but this 4 are the most known. Regarding the technology and the application, the biomaterial used will be also different. So in short I believe that for dental restorations the biomaterial most used may be ceramics, am I right? In any case there are commercial machines that can produce bio-models with functional gradient (different materials), try search the Object from Stratasys (http://www.stratasys.com/3d-printers/technology/polyjet-technology) for me one of the best in the market, but very expensive. There are others like Bioplotter from EnvisionTec but obviously all the equipments depends on the biomaterial you will use and the mechanical properties you need.

The biomaterials can be metallic, polymers, ceramics or composite materials, the most known biomaterials used (that I know) in Biofabrication is: PCL, PLA, PEEK, HA, Graphene, PEG, ... there are more but the list is kind of huge.

Kind regards,

Dino

My lab work in reproduction with SLS tecnology of cardiac valves

Dear Jun,

I myself recently did some research on 3D printing for dental composites in the case of indirect restorations. What seemed most promising is to continue making your material prior to cutting it, especially if you have complete control over the production process (monomers and fillers). A new useful technology however would be high-powered lasers for cutting which would allow you to reach quasi perfect fit for the restoration and obtain high-quality surfaces compared to milling. A Belgium company LASEA (www.laser-ea.com) specializes in laser micromachining.

Regards,

Luc

Hi to everyone,

@Jitte Groothuis, we (in CDRsp, a research centre from Portugal) are enrolled in a european research centre with the Utrecht University regarding tissue regeneration, in this specificy case for cartilage.

One other thing, you mention ABS but you have to take it to account that this material is not biocompatible, this material is one of the most used to produce prototypes but not in the Medical field.

@ Jun: I'm currently studying the use of certain biomaterials with the SLS technology. But here in my research centre we develop our own technology, we had developed several FDM machines, one micro-multi-SLA, Electrospinning machine for nanofibres and we use them with different biomaterials (that as mention by Richard Bibb is a whole different area that we also are studying).

Kind regards,

Dino

Thank you so much for all of your valuable answers!

Dino, Yes, you are right. I just planed to use ceramics as well as some composite resins or their hybrids to fabricate dental restorative materials

I have another question about biomaterial reconstruction (I may put it in a particular question...): I saw many open-cell foams and structures made with open holes, but not closed cells. Maybe nobody is interested, or it is not possible with the 3D-printing technology, (or I did not find them).

- With powder, I think that the powder would stay in the holes, but

- With the filament technology maybe?

- Do you know some othe techniques to obtain solid foams with very controlled holes sizes, size distribution, position in the matrix, orientation and overall shape? The best would be from biomaterials, in particular food ingredients.

Kind regards,

Solange

Dear Christian,

In fact we run some experiments in FDM with PCL/HA (hidroxyapatite) and it went very well. We use HA in powder and PCL in pellets and we melt the pellets and mix everything in a mortar. Obviously we can't certify 100% the homogeneity of the mix, but it create very good results. We intend to use in bone tissue engineering and see the results comparing with simple PCL scaffolds.

Warm regards,

Dino

It is an interesting topic. I would like to know as well.

Hi Jun Yue,

maybe you want to take a look at ILT in Aachen - they print a lot implants (metals or ceramics) and also bio-resorbable implants:

http://www.ilt.fraunhofer.de/content/dam/ilt/en/documents/product_and_services/laser_material_processing/HO_Manufacturing_%20of_resorbable_Implants_using_SLM_2011.pdf

I think they probably can help you. But those industrial machines are much more expensive than the plastics printers.

Hi Jens,

Thank you for your information. Yes, it will be a good chance to contact ILT.

Jun

Hi Jun Yue, my research is dealing with 3DP for biomaterial.

Some specific applications, including multi-photon processing, (a.k.a. two-photon polymerization) of organic-inorganic hybrids are described here:

https://www.researchgate.net/publication/230789066_Engineering_3D_cell-culture_matrices_multiphoton_processing_technologies_for_biological__tissue_engineering_applications?ev=prf_pub

Article Engineering 3D cell-culture matrices: Multiphoton processing...

This kind of methods will be more applicable if you can find any way to construct an isolated living cell ( with the help of live cell culture methods)

I am printing my scaffolds by 3DP technique. I am using a CAD software called Autodesk Inventor to design the scaffolds. People usually have the wrong concept on 3DP where it is normally assumed that 3DP can print anything that you wish. No. That is totally wrong. There is also limitation on 3DP technique. So, firstly I suggest you have to decide your design and then choose the right rapid prototyping technique.

The best is to simulate the copliance of the vessel in the model . we have done this several times There are some publications existing like Flow in tubes and arteries Biorheology 1986

Best regards

Dieter Liepsch

I am attempting to print ceramics.

We have been printing biomodels for surgeons, dentists, medical device designers and artists since 1997, so we have quite a bit of experience. We typically start from 3D medic al imaging data, usually CT or MRI. As you correctly surmise in your first question, the type of material and how the printer works are deeply intertwined. To paint a broad picture, there are several major additive fabrication methods:

1) extrusion

2) layered polymerization

3) powder based

4) lamination

1) Extrusion 3D printers commonly start with either a filament of polymer such as ABS which is melted at the extrusion tip (fused deposition modeling like MakerBot, RepRap, and Stratasys FDM machines) or a melted liquid material (e.g. chocolate, sugar solution) which hardens by cooling or hydrogels which may polymerize enzymatically, pH change, etc. (e.g. EnvisionTec Bioplotter, Organovo).

2) Layered polymerization machines typically start with a liquid resin which is polymerized by light. They can polymerize certain regions using a laser (e.g. stereolithography or SLA machines like 3D Systems or FormLabs), use digital light projection (EnvisionTec), or polymerize the entire layer after laying down different build and support materials (e.g. PolyJet or Multi Jet Modeling from Objet (now part of Stratasys) or some of 3D Systems ProJet machines).

3) Powder based methods typically use either an adhesive or heat to fuse finely powdered material. Z-printers (formerly Z-Corp, now part of 3D Systems) use an adhesive binder to hold the powder together followed by infiltration with cyanoacrylate or other material to strengthen the part. Figulo uses modified Z-printers and replaces infiltration with baking in kiln to make ceramic parts, but they are quite fragile. Most other powder systems use lasers (EOS) or electron beams (Arcam) to either sinter or melt the particles together. These methods (Selective Laser Sintering, Selective Laser Melting, Electron Beam Melting, etc.) can make extremely strong parts in materials such as nylon, PEEK, chrome alloy or titanium and are probably the best choice for strong ceramics.

4) Laminated Object Manufacturing where thin layers of a material are glued together and cut layer by layer is less common, but MCOR has recently revitalized with printers which use paper as a raw material.

Some printers like SolidScape combine additive fabrication with subtractive methods (like milling) to provide extremely accurate models. SolidsScape parts are made in wax patterns which are used by jewelers and dentists to cast in various metals. VoxelJet focuses on making larger patterns for industrial use (e.g sand casting). These illustrate an important principle, that even if you can’t find a printer that works in the material you need, you may be able to making the molds or tooling by 3D printing.

This is just a broad overview to give some idea of the connection between the technologies and materials used. There are many variants of these and new technologies are being developed all the time. Unfortunately, it means that there is no one answer to the last part of your third question. You first have to define what materials and mechanical properties you need and then find the right machine and vendor for your project.

Best of luck,

Crispin