One of the most promising fields for 3D printing applications is the medical industry, which requires customizable, biocompatible, and sterilizable plastic and metal components. Although additive manufacturing may seem like science fiction, a growing number of medical applications are being developed using this technology every year.
Using 3D printing, patients are able to obtain efficient and affordable custom implants, prosthetics, and devices; it gives doctors new tools to perform their jobs more effectively; and it enables medical device manufacturers to design better products more quickly. Research is even being conducted to print living tissues and organs in 3D!
3D printing for medical purposes has many advantages
Why is 3D printing so useful in the medical field? 3D printing aligns well with the capabilities of modern medicine in many ways.
It is necessary to design implants, prostheses, devices, anatomical models, and even tools according to the specific needs of each patient. The process of customization is time-consuming and expensive with traditional technology. As an alternative, 3D printing can produce small runs of custom parts at no extra cost and without any tooling or setup time. Human bodies are among the most customized of all products, and additive manufacturing excels in these applications.
It is common for medical devices to have complex designs, internal geometries, or organic shapes. Consider, for instance, the spirals and hollow spaces on a hearing aid or a heart! Traditionally, these shapes would be difficult or impossible to make.
With 3D printing, one piece geometries can be easily produced in plastic or metal with high accuracy. This can lead to improved designs as well as reduced costs and production times. In addition to facilitating easier sterilization, eliminating crevices and gaps between multiple parts makes devices more difficult to grow bacteria on.
A device’s materials are as important as its design when it comes to medical devices. The printing of 3D materials offers mechanical, chemical, and thermal properties that make them perfect for use in biocompatible and sterilizable material. You can print 3D printed components that are rigid or flexible and smooth or textured. Almost any application can benefit from 3D printed materials.
Compared to other technologies, 3D printing also offers unparalleled production speeds. The treatment of patients is no different. Because of the lengthy timeline for traditional manufacturing, patients often have to wait months to be able to begin their treatment program or go to multiple doctors and undergo multiple intrusive procedures to wear and rewear their medical devices. The patient is inconvenienced and may experience additional discomfort at best. The patient’s condition can worsen or even be fatal if there are delays in treatment.
As a final benefit, 3D printers have made it possible for medical professionals to eliminate plaster casts by using 3D scanning and x-rays to quickly create 3D models, eliminating the need to store countless physical casts. Besides saving space, this also reduces the potential for damage from mishandling or aging. A 3D model is an accurate, permanent model that can be accessed anywhere, saving time and money for medical professionals.
Using 3D printing in the medical field
3D Printed Prosthetics
Prosthetic medicine requires intense customization, which makes the fabrication of prostheses time-consuming and expensive. Since these devices and their sockets are subject to rigorous use, a perfect fit is critical in creating a reliable, comfortable and functional prosthesis for the patient. All of these reasons and more have contributed to the revolution in the field of 3D printed prostheses.
In general, multiple castings and follow-up appointments are necessary to fine-tune the fit of the prosthesis. Patients who may be sensitive about their condition often feel that this is more than just an inconvenience: Having a cast made can be uncomfortable, and the many fittings can be invasive. Not to mention that the time spent on fitting and re-fitting represents the time without a properly fitted prosthesis.
By using 3D printing, patients no longer have to wear a physical cast. As an alternative, technicians can use 3D scanners to quickly create a 3D model of the residual limb. Based on this 3D scan, a 3D-printed socket can be made that is both accurate and affordable, which typically only requires a single fitting to complete.
Devices and implants customized for each patient
Customization is not limited to the field of prosthetic medicine. Devices (like hearing aids) and implants (such as artificial joints, cranial plates, and even heart valves) are increasingly turning to 3D printing for its flexibility and speed.
The traditional way of adjusting hearing aids and heart valves has been extensive, handcrafted adjustments over a week or more. From casting to fitting, a hearing aid required nine steps before 3D printing. Hearing aids can now be scanned and printed in a single day with 3D scanning.
There are also design advantages: 3D printed silicone heart valves provide an exact fit that rigid, traditionally manufactured heart valves simply cannot. Implants such as titanium artificial joints or cranial plates can be printed with complex, porous surfaces that are less likely to be rejected by patients’ bodies.
Orthodontics and dentistry
Orthodontic devices and dental implants require extensive customization with high precision. Dentures, crowns, implants, and retainers must be durable, precise, and comfortable because our teeth stand up to heavy use day after day. Additionally, they need to be made of biocompatible materials such as cobalt chrome and porcelain.
Using 3D printing, dental and orthodontic professionals can accomplish all of that faster and at a lower cost than traditional methods like machining. Dental devices can be produced quickly and easily using 3D scans and x-rays rather than castings or setups.
In the case of devices such as braces or expanders that do not require 3D printed components, 3D printed models made from sterilizable plastics can be used to measure form and fit, eliminating the need for patient fittings or repeat visits.
Development of medical devices
Research, development, and certification of medical devices are extremely time-consuming and resource-intensive. Often, the high price of medical devices is not caused by manufacturing costs, but by expensive product development. Because 3D printing offers a variety of biocompatible and sterilizable materials, it allows medical device developers to produce and test functional prototypes in a fraction of the time, resulting in better products and lower costs.
The advantages of additive manufacturing for product development include its quick turn-around time, ease of alterations and low cost for very small volumes of parts. It can save businesses hundreds of thousands of dollars and months of time in product development. Medical devices must undergo a rigorous and lengthy certification process, so these time and cost savings are especially valuable.
Customized surgical instruments
Precision and efficiency are critical in the operating room. The unique challenges of each procedure cannot be overstated-each patient’s body is different, as are the hands of each surgeon. If fine control is essential, why should surgeons be restricted to one-size-fits-all tools?
By using 3D printing, personalized surgical tools can be produced quickly and affordably, tailored to the particular needs of each surgeon and each procedure. These tools are made of sterilizable and biocompatible plastics and metals. These tools can be made so quickly that hospitals don’t need to keep a large back stock of instruments, but instead can order them as necessary.
Instruments that are customized to the size and shape of each surgeon’s hands, along with customized features tailored to each application, can greatly improve outcomes and efficiency. Moreover, surgical guides made specifically for each patient can increase accuracy while decreasing the amount of time spent in the operating room by eliminating the need to consult diagrams and assistants.
Models of custom anatomy
Anatomical models are expensive, and even the best offer a limited range of options. Professionals and students regularly use models for education, training, surgery preparation, and to provide visual aids to patients.
3D printing can help medical professionals and educators create affordable custom anatomical models. Surgeons can practice difficult surgeries using patient-specific models that reproduce exactly what they will encounter during surgery.
Bioprinting
Wouldn’t it be interesting if 3D printers used cells and organic matter instead of plastic and metal? That’s the basic concept of bioprinting—the cutting edge of 3D printing in the medical industry.
Although most bioprinting technologies and applications are still in their infancy, researchers have successfully printed bones, skin, and cartilage. One day, we may even be able to 3D print functioning organs.
Bioprinting works similarly to other 3D printing techniques: material is deposited or solidified in successive layers to create 3D objects. In bioprinting, however, the cells are cultivated from tissue samples or stem cells. A binding gel or collagen scaffold holds the cells together.
Bio printed body parts and organs would allow the patient’s own tissue to grow over the 3D printed parts and eventually replace the cells with their own. While we’re unlikely to see functioning bio printed organs anytime soon, the technology is already helping researchers conduct research on living tissues without having to take them from a living organism.
3D-printed medical materials
Not all materials are created equal when it comes to medical products. As microorganisms can cause life-threatening infections, medical devices and implants must be sterilizable. A product that will come into contact with tissue must also be biocompatible, which means it will not produce harmful reactions if placed in a biological system. In particular, implants must be made of materials that are likely to be accepted by recipients’ bodies. Our bodies’ fluids are surprisingly corrosive over time, which is why corrosion-resistance is just as important. In order to withstand heavy long-term use, implants must be strong, durable, and lightweight.
Modern 3D printers are compatible with a range of plastics and metals that meet these requirements. We’ve outlined a few of the most commonly used 3D printed materials for the medical industry below.
Nylon PA-12
Plastics like this are lightweight, corrosion-resistant, durable, and can be sterilized with steam autoclaves. The nylon PA-12 is flexible and chemically resistant. Additionally, it is among the fastest and most affordable medical-grade materials to print, and it is compatible with Multi Jet Fusion printing and SLS. The nylon PA-12 is USP Class I-VI and ISO 10993 certified.
PC-ISO
FDM 3D printing uses PC-ISO, a biocompatible polycarbonate (PC) engineering thermoplastic. The material has a lower-quality finish than Nylon PA-12, but it is commonly used for surgical guides, prototypes, and molds. The PC-ISO can be gamma sterilized or EtO sterilized and is USP Class I-VI and ISO 10993 certified.
ABS M30i
ABS M30i is another biocompatible engineering thermoplastic for FDM, just like PC-ISO. Functional prototypes, form-fit tests, and end-use parts are perfect for FDM printing. ABS M30i can be gamma or EtO sterilized, and it is USP Class I-VI and ISO 10993 certified.
Titanium
The most popular material for medical implants is titanium, the king of biocompatible metals. All types of replacement joints, pacemakers, cranial plates, dental implants, and more are made of titanium. Titanium is a strong, lightweight, corrosion-resistant and non-reactive metal. DMLS, one of the most expensive 3D printing technologies, can be used to print it
Cobalt Chrome
Cobalt chrome also exhibits excellent corrosion resistance and biocompatibility, like titanium. It possesses additional strength and hardness over titanium and is commonly used for replacement teeth as well as heavy-use joints like hips, knees, and shoulders. DMLS is also used to 3D print cobalt chrome.
Stainless Steel
Steel is strong, sterilizable, and biocompatible; however, it does not offer the same long-term corrosion resistance as titanium or cobalt chrome. Therefore, stainless steel is used more often in surgical tools and temporary implants like bone screws. Direct material printing makes it possible to 3D print stainless steel parts at a much lower cost than other metals. The strength, rigidity, and chemical resistance of different types of stainless steel vary.
Silicone
Rubber materials such as silicone have a wide range of applications in the medical and food industries. For biocompatibility, it can be certified as Class V or Class IV. Silicone can be used for both short- and long-term implants. Silicone is commonly found in catheters, respiratory masks, medical tubing, and seals.
While silicone 3D printers are still in their infancy, silicone casting with 3D printed molds is a fast, affordable way to produce high-quality parts and products.
The Future of 3D Printing in Medicine
Due to the unique needs of each patient and body, medical devices often require the most customization of any product in any industry. Because of the high costs and long lead times of tooling for traditional manufacturing, these devices have historically been expensive and slow to produce. With its ability to produce small runs of highly customized parts, 3D printing is redefining what is possible in medicine.
Adapting medical solutions to patients and doctors improves outcomes and reduces costs and production times, which increases accessibility. Custom medical devices, implants, and tools are now more accessible than ever. As 3D printing technologies continue to advance, healthcare providers and researchers will continue to explore new applications from implants and surgical tools to tissues and functioning organs.
