Learning the basics of design for bioprinting is both free and easy

Mr Hall, there is a wealth of information available on the future of bioprinting in dentistry. How printing with living tissue is accomplished is still rather vague for many dental clinicians. You recommend that dental clinicians try your CAD project of a human skeleton to learn the basics of bioprinting. What do they need to get started?
There are a number of open-source anatomy scans that have been converted into STL files for CAD available online for free. I selected one that I could verify was as accurate as possible. You can use any free CAD software available online and import the STL file into it. The next steps involve importing the skeleton into 3D software that allows you to interact with meshes. The skeleton has a pre-existing mesh; however, the mesh is continuous, not for each individual bone.

The process involves going into editor mode and selecting the mesh for each bone, which allows you to separate the bones into their own individual digital pieces that you can work on. You then transform the mesh into a wireframe, essentially turning it into a hollow structure with lines similar to a spiderweb.

This wireframe can be adjusted for concentration and scale, effectively changing its gauge. The wireframe can then be smoothed out, giving it an organic look perfect for creating orthopaedic structures or any desired type of scaffolding for biomaterials to be printed on to and grow from.

Can you expand more on how this would work in practice, specifically with something like a mandible?
Sure. For instance, with a mandible, the CAD software has all these little tools that allow you to transform the mesh into a wireframe. This wireframe becomes hollow, allowing you to adjust the concentration of the mesh. Then using the fillet operation, you can smooth out a corner and can provide a rounded radius, giving the wireframe this really nice organic look, if desired.

For my project, I’m looking to create an orthopaedic structure, something like an exoskeleton for bones, to which you could add additional filler or a bone graft. This wireframe lattice on the outside is helpful because the bone still needs to be able to connect to the surrounding tissue.

With advancements in additive manufacturing, such as metal laser sintering, these wireframe structures can be created more easily and cost-effectively using bio-stable materials such as titanium and ceramics.

What further steps could clinicians try out?
The next step involves a subsection called topology optimisation. This allows you to run a simulation on the structure under tension, torsion, compression or expanding force. By applying the specific forces acting on the structure, you can see how the bone will react and how the force is distributed in the bone.

This process, called finite element analysis, is used a lot in engineering. Some software allows changing of the concentration of the meshes in areas of higher and lower force, creating a more optimised part. This is a very interesting science with a lot of possibilities across medicine in dentistry, resulting in a part that is both bio-identical and strong.