Although 3D printing originated in 1984, the technology has caught fire in the past 15 years or so. It’s become a buzzword in many industries involved in engineering and design (and, more recently, medicine). With all of the publicity surrounding it, it’s reasonable to wonder, “is 3D printing the best option for my anatomy models?” For that answer, let’s dive a little deeper.
3D Printing: How It’s Used
3D printing is used for anatomy models! For hard structures, such as bone models, 3D printing may be the sole process used to create the finished product. For tissues of the body, however, there are varying levels of elasticity and softness. After all, most structures of the human body are comprised of soft tissue, not rigid like bone. This is where things get a little more interesting.
To create 3D-printed anatomy models, there has to be an “outline” to define the shape and size. For this, 3D CAD (computer-aided design) data is created of the anatomical structures. This CAD data can be created by using patient data as a starting point or a combination of digital sculpting and engineering software.
After the CAD outline is finalized and accurate to replicate the anatomical shapes and required pathologies, the power of 3D printing is utilized. A prototype (known as a “master”) is 3D printed using the CAD data to allow for a physical product to be visualized for the size and dimensions of a model for client review and approval.
If everything looks good, this master is used as a master pattern for a soft mold to be created around it. This mold brings us to where the magic really happens.
3D Printing: How It’s NOT Used
As beautiful as the 3D printed master is, it’s rigid and therefore not representative of soft tissue. In order to produce a clinically relevant, reusable, durable, and economic soft tissue model, soft materials are cast into the soft mold created from the 3D-printed master model.
This process is highly customizable because the recipe for the soft cast materials can be adjusted repeatedly using the same mold until the exact desired soft tissue feel is created. This is not unlike using the same muffin tin one day to make corn muffins, the next day chocolate cupcakes, and mini quiches the day after. The recipe is different, but the shape remains faithful to the original 3D data/master/mold shape.
When the correct mixture of soft materials is finalized to match the desired clinical scenario, you’re left with a visually beautiful and anatomically accurate model in shape and feel.
Bringing It All Together
Think about 3D printing as a tool that leads to a beautiful final product made of soft materials. The 3D-printed master allows for wonderful visualization, as well as the ability to act as the pattern for a soft mold to be created around it. However, this rigid version of the model simply won’t do as the final product if you wish to provide the most clinically relevant experience while remaining economically responsible.
Rigid 3D printed models require significant labor time for sanding, they cannot replicate the elasticity, responsiveness, and feel of human soft tissue, and they simply don’t last as long as soft cast materials before the color and material properties start to fade. There are competing technologies in 3D printing, but they do not meet the intended purposes of a quality medical demonstration model.
For instance, 3D printing with cells or gels is technically an option, but this has even more limitations than rigid models. While 3D cell printing may be advantageous for research and development purposes where a high degree of tissue property realism is key and convenience is not a requirement, it is not ideal for demo and training uses because it is costly, requires a biologist, are difficult to maintain and has a short shelf-life.
3D printing soft materials is another technology. While this option has a longer shelf-life than cell and gel printing (or cadaver parts) and eliminates the issue of only being able to print rigid structures, it significantly lacks clinical relevance because the product does not feel or behave like soft tissue. Additionally, this process leaves a 3D print texture that cannot be sanded out due to its soft nature.
For it all to come together, soft casting materials are the best combination of realism, economy, and convenience.
Soft cast models are better than 3D printed parts in the following ways:
- The finishing work is done once for the master, so there is minimal labor to create more parts.
- You can make more models in less time.
- Cast parts are more durable and will last much longer, precluding the need to replace them.
- These models do not need to be kept in a very specific temperature range like 3D cell printing models and cadaver parts do, making them easier to transport and ship.
- They’re created from a mold (and therefore identical), so they’re able to deliver the same experience every time.
- These models have a clean, professional appearance to reflect well on your brand.