Interview conducted for the March/April 2024 magazine, published online on July 25, 2024. The speaker’s statements and outlook retain that historical context; research examples do not establish clinical validation for every device.
During the past 7+ years, I have had the pleasure to see ceramic 3D printing being applied in an increasingly diverse range of fields: healthcare & medical, aerospace, energy, architecture and even art. Of all these fields, I remain fascinated by the applications of this technology in the healthcare and medical fields. If you have a slight interest in ceramic 3D printing, you probably already know that the landscape of ceramic 3D printing technologies that can enable such applications is very broad. But to be honest with you, I probably owe my fascination to Lithoz’s technologies – and I will tell you why.
Regular 3D ADEPT Media readers will probably know Lithoz. In 2024, the company had more than a decade of activity behind it and presented three technologies: LCM, LIS and LSD Print. In November 2023 it announced a strategic shareholding in AMAREA Technology, rather than a full acquisition of the company. Medical, aerospace and semiconductor applications are among its target fields; this interview explores LCM’s possibilities for healthcare.
LCM and multi-material research
Lithography-based ceramic manufacturing, or LCM, uses ceramic particles suspended in a photosensitive resin, which is cured by light layer by layer. After printing and cleaning, debinding removes the organic binder and sintering densifies the ceramic. Materials, process and finished device need evaluation for their intended use, as outlined in Lithoz’s medical-device production guide.
Over the years, the Austrian company has expanded the scope of this technology with the release of new materials, opening up new applications in dentistry. In what has become our traditional one-on-one, Daniel Bomze, Director of Medical Solutions, told me what has been happening behind the scenes ever since they unveiled their Lithium Disilicate material.
“It all comes down to three main points:
First of all, 3D printing applications for highly aesthetic dental restorations with our lithium disilicate material are gaining traction in the dental field. We continue to receive tremendous interest in these applications across the world. Our latest appearance at the LMT Lab Day in Chicago reflects that interest. This market will continue to see huge traction moving forward, as it highlights a new way of manufacturing after decades in the field.
We have also been involved in several interesting projects where we could push the boundaries of what’s possible with our multi-material ceramic 3D printing.”
The CeraFab Multi 2M30 was launched in late 2020, as stated in Lithoz’s 2021 announcement. It can combine two materials within a single layer to bring different properties into one part. This creates design opportunities, but does not itself guarantee the finished component’s performance.
“As far as the healthcare field is concerned, we focused especially on multi-material bone replacement solutions”, Bomze explains. “One example that is worth mentioning here is the mandibular augmentation after bone atrophy which so far has always consisted of one material. Normally, you have a bone replacement material and on top of it, you always need a kind of membrane to prevent premature ingrowth of soft tissues. Indeed, if a soft tissue like gingiva grows into the scaffold, there will be no residual space for the bone itself.
This is possible because bone will just grow much slower than the soft tissue. That’s why as part of a research project, we combined a comparably fast resorbing material like tricalcium phosphate with another very good bioactive material of hydroxyapatite on the outside shell in order to obtain a ceramic membrane. This ceramic membrane then should prevent the ingrowth of the soft tissue during the healing phase. We are very happy with the results so far; we will hopefully share more details on this project soon.
And the third topic that has been receiving a lot of attention lately is surgical tools like burs and shavers as well as similar applications. We found that we actually hit the nerve of the industry here because it is often quite challenging to achieve high quality in traditional manufacturing and being able to achieve high productivity with a lot of design freedom with ceramic 3D printing is something we are very proud of,” he adds.
The mandibular application above was described as an ongoing research project. Detailed results and the device’s validation status were not supplied in this interview.
Applications with different requirements
The applications discussed span anatomical models, tools and implants, as well as ceramic scaffolds for bone regeneration. These manufactured and sintered scaffolds should be distinguished from bioprinting living cells: the LCM process described here does not directly print living tissue.
Maturity varies between devices. The design examples and testimony in this interview do not establish a general improvement in cure rates or surgical efficiency.
One thing I specifically like about Lithoz’s approach is that not only does their medical engineering team go the extra mile to improve the manufacturing process, taking into account the limitations of conventional manufacturing processes, they also take into account existing limitations of their proprietary technology. In the end, do we not say: “Compare yourself to who you were yesterday”?
Bomze outlines here that “surgical tools have gotten significant interest from medical professionals because one could now drastically improve the mechanical properties of 3D-printed high-performance ceramics. This is something that’s not easy to achieve in conventional manufacturing given the lack of desired properties often delivered by the materials.”
Speaking of their LCM technology and how they have been able to push its capabilities, he adds: “we could also broaden the processing window of some of our materials. This means that with the same material, we could produce very delicate parts with tiny features as well as bulky parts which are really sturdy and for load-bearing applications (an artificial hip joint for example). A year ago, we would have told medical professionals that this “wall thickness” is not possible to achieve with our LCM technology. With the advancement in material today, we can develop custom or patient-specific artificial hip joints.”
These statements describe manufacturing possibilities according to Lithoz. Producing an implant geometry does not by itself demonstrate market authorization or a clinical benefit.
The shaver: integrating several functions
To illustrate functional integration, Bomze uses the example of an arthroscopic knee shaver. This is an instrument-design example; the interview does not establish the appropriate treatment for a meniscus injury or show that surgery would be inevitable.
“Depending on the way the surgeon operates the device, it will go inside the tissue or remove a superficial amount of tissue, with all the tissue that has been removed being sucked away through the big central channel. There are also different channels on the upper side with different diameters in this specific tool, which used for rinsing the surgery site with a rinsing fluid while the central upper channel holds a glass fiber (light guide) to illuminate the surgery area. This should help the surgeon to have a better view and control, thus only removing what is torn and not healthy tissue. AM will help to produce such a complex tool while reducing the necessary assembly steps significantly.”
The manufacturing benefit proposed is to integrate suction and irrigation channels and a passage for a light guide into a complex geometry with fewer assembly steps. Lithoz illustrates these functions in its arthroscopic shaver example. No comparative results supplied here establish reduced scarring or maximum durability.
Depending on the material and component, a conventional route can combine shaping, thermal treatments and machining. Hot isostatic pressing (HIP) is a densification treatment under heat and pressure, not a milling operation. Its use should be distinguished from any machining required for finishing.
Building repeatable medical production
Bomze’ example made me question the different manufacturing requirements in a medical environment. As a trade press that covers the use of AM across various industries, it’s easy to talk about the importance of an AM factory in an industrial setting. In a medical/healthcare environment, I was curious to know what it looks like.
“First of all, surgeons get their 3D-printed parts from medical device manufacturers who remain Lithoz’s key targets in this industry”, Bomze clarifies. “That being said, there is a broad variety of companies that would be able to build up an AM factory for medical devices.”
The production chain includes the printer, cleaning equipment, debinding and sintering equipment, and suitable materials. Raw-material biocompatibility does not remove the need to evaluate the finished device. The manufacturer’s guide distinguishes equipment qualification, process validation, quality control and traceability.
“What’s important to keep in mind is that this AM factory – if made up of the right equipment – will allow you to achieve freedom of design while saving time and costs where necessary. It’s not only about the 3D printer but also about having quality standards from A to Z that could help you deliver predictable and repeatable results in serial production.
What we learned during the past 13 years is that a predictable and repeatable result is important for most of our customers. It is even more important in medical device manufacturing as part manufacturers must achieve the same result every single time. In this vein, it’s our duty as manufacturers of such AM factories to offer the possibility for automated documentation of the production process, and also smart designs of our devices and software to prevent human errors.”
Lithoz’s range of technologies and materials also targets sectors beyond healthcare. Suitability needs to be assessed against the production requirements of each application.
While cost and performance comparison between a Lithoz’s AM factory and another factory (powered by conventional manufacturing processes or other AM technologies) are too broad and complex to be discussed in this article, I strongly believe the applications discussed today and the partnerships the company continuously signs in the healthcare industry testify to the potential of their solutions.
In the end, whether we talk about dental restorations, surgical tools or implants, Lithoz’s journey shows that advancements are being made in the research and application of ceramic 3D printing technology in healthcare. Being able to witness its development one step at a time makes me confident that its best days are yet to come.
This content has been produced in collaboration with Lithoz. It was first published in the March/April edition of 3D ADEPT Mag.
Review note: the launch date has been aligned to 2020 in the French version; the shareholding, debinding stage and role of HIP have been clarified. Manufacturing possibilities have been distinguished from clinical benefits not demonstrated in this interview.
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