How to 3D Print Medical Items

Initially, 3D printing was mostly employed by large corporations that could afford costly printers and materials. 3D printing has grown and become more economical over time, making it an excellent choice for a wide range of sectors. In the healthcare sector, medical practitioners are starting to employ 3D printing to better their practices and provide patients with more personalized and inexpensive healthcare solutions.

3D printing developments in healthcare have resulted in lighter, stronger, and safer solutions, as well as shorter lead times and reduced costs. Personalized custom parts are made available with 3D printing. This improves medical providers' understanding of patients' needs and increases patients’ comfort by allowing engagement with devices made specifically for their anatomy.

In this comprehensive guide, we look at the different technologies and processes employed in 3D printing medical items and the applications of 3D printing for medical devices.

Different Technology Used in 3D Printing Medical Items

There are different 3D printing technologies used for 3D printing medical devices. It is critical to select the appropriate printing technique for each application. Below are the most common technologies in use today.

1. Stereolithography (SLA)

One of the distinguishing features of stereolithography is rapid technological advancement. 3D printing has progressed significantly since its birth, due to the constant advancement of equipment and the use of higher-quality materials.

This printing technique has also improved in precision and resolution, often surpassing that of 3D scans or digital templates created using a computer-aided design system. High precision and resolution are one of the features that make stereolithography so popular among medical professionals.

In a technique known as photopolymerization, SLA 3D printers use a laser to cure liquid resin into a rigid or flexible plastic. The printer directs a specific wavelength of light to the resins and as a result, small molecular chains come together, polymerizing monomers and oligomers into hardened rigid or flexible shapes.

Pros of SLA technology

• This technology offers very high resolution and accuracy.
• SLA parts provide the clearest details and smoothest plastic surface finish compared to other printing technology

Cons of SLA technology

• SLA 3D printers are relatively more expensive.
• Post-processing is required. This usually involves washing and post-curing

If you require a highly detailed medical device prototype that requires tight tolerances and smooth surfaces, then SLA is an excellent choice. This technology is also great for molds, tooling, medical models, and functional end-use items.

2. Fused Deposition Modeling (FDM)

Fused deposition modeling, also known as Fused Filament Fabrication (FFF), is a printing technology that creates items by melting and extruding thermoplastic filament and depositing it layer by layer in the build area using a printer nozzle. The medical field is one of the most common applications of FDM technology.

Pros of FDM technology

• FDM works with a variety of thermoplastics, like PETG, PLA, ABS, and their blends.
• Several FDM printing materials are biocompatible
• It is fast
• It is budget-friendly

Cons of FDM technology

• Low resolution
• Finished products usually have rough surfaces that require post-processing for a smooth finish
• FDM prints are prone to breaking because, in most FDM printers, the filament is deposited layer by layer in one direction.

FDM is suitable for surgical models that are geometrically simple and do not require a lot of intricacy or sophisticated characteristics. During the COVID-19 pandemic, FDM technology enabled the printing of various healthcare items such as face masks, artificial breathers, and some other medical items.

3. Selective Laser Sintering (SLS)

Selective laser sintering is a dependable and robust 3D printing technology for a variety of biomedical items.  SLS printers fuse small particles of polymer powder using a high-powered laser.  During printing, the unfused powder supports the item thereby eliminating the need for dedicated support structures.

Pros of SLS technology

• No support structure is needed, making it ideal for complex geometries
• High accuracy and speed
• Some SLS printing materials  are biocompatible

Cons of SLS technology

• High entry price
• Limited printing material

High productivity, biocompatibility, and established materials are all features of selective laser sintering that make it common among medical items developers for functional prototyping. It is also a cheaper option for bridge manufacturing. SLS parts are normally white with a grainy matte appearance. This will make an excellent replica of bone.

4. Selective Laser Melting (SLM) and  Direct Metal Laser Sintering (DMLS)

Selective laser melting (SLM) and Direct metal laser sintering (DMLS) 3D printers work similarly to SLS printers, except instead of polymers, they employ a laser to fuse metal powder particles together layer by layer.

The ability of DMLS and SLM 3D printers to generate robust, precise, and sophisticated metal products makes this technology perfect for a range of medical applications. This method uses medical imaging (MI) techniques such as magnetic resonance imaging (MRI),  X-rays, and computed tomography (CT) scans to create implants that match the anatomy of the host tissues.

Pros of DMLS and SLM technology

• Supports metal material
• Materials are biocompatible
• Can produce complex geometries
• Can be used in the production of generic implants like knees, hips, spine
• Can be used for custom implants for cancer treatment
• Finished items are strong and durable
• Can also be used for orthopedic and medical technology items

Cons of DMLS and SLM technology

• Complex workflow
• Expensive to set up

This technology is a promising technique for the fabrication of various medical items.

5. 3D Bioprinting

3D Bioprinting, often known as bioprinting, is a type of additive manufacturing that creates 3D structures that are functional as 3D tissues, using cells and biomaterials known as bioinks rather than typical metals and plastics. Bio inks are biomaterials that closely resemble the composition of bodily tissues.

3D bioprinters work exactly like other 3D printers.  Bio inks are placed into the printer and extruded from the nozzle to form filaments, which are deposited layer by layer to produce desired structures. However, bioprinters can carry out noncontact droplet printing.

Pros of bioprinting technology

• A great way to provide organs
• Affordable approach
• Quicker and more detailed

Cons of bioprinting technology

• Low viscosity bio-inks are required
• Droplet placement precision concerns
• Hazardous chemical emissions

Biocompatible 3D Printing Material

Biocompatibility as the name implies is a general term that refers to a substance or material's ability to work with living tissue without causing harm or complications. Biocompatible materials do not cause toxicity or immunological reactions when in contact with the body or bodily fluids. Biocompatibility is important in 3D printing medical items because systemic toxicity can render entire biological systems dysfunctional. So, only biocompatible materials should be used for 3D printing medical items.

Biocompatible materials should be non-carcinogenic, non-toxic, have no birth defects causing ability, immunogenicity must be absent, and they must have high mechanical resistance, and high corrosion resistance.

Polymers, ceramics, metals, composites, bio-inks, and carbon compounds are commonly used biocompatible 3D printing materials. Polymers such as polyglycolic acid, polylactic acid, polycaprolactone, and their copolymers are extensively utilized as biocompatible 3D printing materials.

 Medical Items That can be Made with 3D Printing

• Surgical instruments

Some surgical instruments made using 3D printing technology include forceps, medical clamps, retractors,  hemostats, needle drivers, and scalpel handles.

The main advantage of 3D printing in the manufacture of these medical tools is that specific alterations to designs may be made, typically based on input from surgeons after using a prototype. Because of the speed with which designs may be modified and printed, changes can be made quickly, even on the same day they were made.

Using additive manufacturing, full surgical sets with forceps, needle drivers, and several other items can be built within an average of just six hours. Very fast process.

• Prosthetics

3D printing is widely used in the production of patient-specific, customized body parts such as fingers, toes, and limbs.

This has an advantage over traditional manufacturing methods because it allows for more complex designs. Traditional methods usually entail costly casting and recasting to get a finished product that fits the patient, but 3D printing allows for far greater control of the final product which is lighter and stronger as a result of the material used.

• Organs and tissues 

Bioprinting-the process of depositing living cells layer by layer into specific shapes to form tissues and organs- is the technology employed for making human organs and tissues.

Professionals can use the patient's cells in this process. Doing this eliminates or significantly reduces the chances of the patient's body rejecting the printed organ or tissue because the material used is from their own body. 

Since the early 2000s, simple organs such as bladders have been successfully bioprinted and transplanted into patients, but more complicated structures are yet to advance beyond the prototype stage. However, experts say that the future is bright for printing more complex body structures.

• Orthopedic implants

Additive manufacturing has also shone light on the manufacturing of medical devices to replace damaged bones, or replace missing bones and joints.

3D printing allows perfectly fitted devices to be made because of its customization options, the ability to print complex geometries and structures, as well as material versatility. Rapid prototyping is also possible thanks to 3D printing.

Due to developments in 3D scanning and imaging technologies (MRI, CT, x-rays), these designs can be more sophisticated, the best materials for optimal function can be chosen, and the final design will have a very perfect fit.

Dental restorations, such as crowns, fillings, bridge replacements, and dentures, can also be 3D-printed. The developments in computer-aided design (CAD) and computer-aided manufacturing (CAM) technology have also positively influenced the process of dental restoration.

Conclusion The 3D printing industry is actively taking the healthcare sector to the next level. 3D printing of medical items is now possible, even organs and tissues like the bladder. The different 3D printing technologies employed for this have been covered, and the different medical items that can be produced from 3D printing are listed above. While more complex medical structures have not yet passed the prototype stage, experts believe that this will be possible soon.