Medical innovations involving the use of 3D printing in cutting-edge surgical processes have been making the headlines a lot recently. Less heralded, but equally exciting are some of the groundbreaking new applications of additive manufacturing in the dental field.
Additive manufacturing or 3D printing is an exciting new technology whose benefits are already being embraced in real-life applications, and nowhere more so than in the field of medicine. Success stories involving 3D-printed titanium implants such as vertebral cages and heel joints have received widespread coverage in the popular media. However, in the dental arena, less ‘earth-shattering’ applications of 3D printing may not have found their way into the media. Nonetheless, they are already delivering significant reductions in costs and increases in the speed and accuracy of production of crowns, bridges and orthodontic appliances.
Dutch medical design company Xilloc Medical is one business already making a name for itself through its medical breakthroughs. Already famed for printing a titanium jaw-bone using complex algorithms to create a design that gives blood vessels, nerves and muscles a better opportunity to grow into the implant, Xilloc is now pushing the envelope with its most recent development in the field of skeletal augmentation in facial reconstruction for patients following trauma or congenital defect.
Working with Japanese company Next21, the company has devised a new biomedical approach to 3D printing bone implants. Instead of titanium, the process uses calcium phosphate, the primary constituent of natural bone, called CT-Bone. As with all implants cell behaviour in patients is a critical consideration that CT-Bone seeks to conquer.
Customised medical/dental 3D-printed solutions rely on already available scanning and imaging technology – CT, MRI and ultrasound. Then, CAD-CAM design of the specific part by biomedical engineers provides the path for 3D printing. Appropriately termed ‘digital healthcare’ by one US journal, the uptake across the industry is revolutionary. As a senior clinical maxillofacial prosthetist from Kings College Hospital in London, recently confirmed, 3D printers are now essential in hospitals treating serious head, neck and jaw injuries.
The benefits lie in surgeons now being able to create implants for reconstructive surgery beforehand from scans taken of the patient. These 3D parts are then used to ‘rehearse’ the surgery, gaining familiarity with any intricacies and complexities, thus ensuring the most appropriate procedure is established well before any actual surgery occurs on the patient. This allows for faster and more precise operations, which obviously result in tremendous benefits to both surgeon and patient.
Encompassing a variety of aeronautical, automation and defence applications, SLM Solutions from Lúbeck, Germany, has developed a range of selective laser melting systems with different laser configurations, build-window specifications and production speeds. These metal 3D-printing systems also provide the capability for the manufacture of medical and dental parts. The benefits that these capabilities offer to the manufacturer are enhanced by SLM Solutions’ ability to supply metal powders appropriate for a range of manufacturing purposes, including titanium, stainless steel, and cobalt-chrome.
The properties of titanium and titanium alloy include high strength and low density, a key factor in surgical implants. Additionally it is corrosive-resistant and biocompatible, making titanium highly suitable for medical and dental purposes. While stainless steel is used for the manufacture of medical instruments, cobalt-chrome has replaced this material in the manufacture of hip replacement parts. Aware of the requirements associated with biomedical products implanted in a human body, SLM Solutions provides a nickel-free cobalt-chrome (CoCr) powder. Not only is it suitable for implants such as hip joints, but Co-Cr is particularly useful in dentistry.
As in medical applications, successful dentistry applications of 3D printing rely on oral CT scans to gain patient information as the basis for a digital design. A biomedical engineer then develops the CAD/CAM design and the production process that controls the 3D printing.
Design-controlled, layer-by-layer 3D printing capability removes many of the constraints in traditional manufacturing processes, such as casting, fabrication and milling, which don’t always address the fine detail or complexities required. The advantages of using customised products rather than off-the-shelf implants is a superior degree of comfort for the patient, leading in turn to faster recovery and better functionality.
Reports from dental prosthetists indicate additive manufacturing of crown and bridgework has the opportunity to improve industrial production of modern tooth replacement. Operating with high precision and flexibility, the 3D printing process ensures part accuracy, with none of the potential for human error seen with milling, resulting in a higher-quality final product and reduced costs. Once set up, CAD/CAM data can be modified to suit differing individual requirements with minimal effort, making the system a cost-effective investment over time.
Dental implants have seen consistent growth due to an aging population requiring restorative dentistry. As Australians age and seek to maintain their health and wellbeing, this demand should continue. Additionally as anatomical changes occur over time, patients will require new dentures or removable partial dentures (RPDs), and have been shown to happily wear CoCr dentures.
Contrary to the growth in restorative dentistry through caps and crowns, RPDs or partial dentures are still in demand, particularly where cost is an issue. CoCr provides an appropriate metal for this purpose, having been tested through material science analysis of cross-sectional images that confirms the outstanding quality of the end product. Moreover, testing of finished products using the selective laser melting process offered by SLM Solutions has been shown to achieve even better metallurgical characteristics than conventional casting, strengthening the case for the use of 3D printing in the dental health sector.
Already in use, SLM Solutions 280HL system can generate 400 tooth caps within a few hours. Part accuracy and a perfect fit, look and feel can all be produced with reproduced precision, along with fulfilling the required accuracy and tolerance range during 3D printing. Models may also be directly produced in multiple versions, as a control model or sample, which are break-resistant, unlike common plaster models.
As with medical uses, 3D printing provides dentists with opportunities to provide more accurate and intricate solutions that not only make patient outcomes safe, but offer long-lasting comfort. Research and development in both dental and medical areas to identify and test new additive manufacturing opportunities is occurring in a number of universities across Australia. As recently as March this year, Griffith University’s Menzies Institute pioneered work that could revolutionise dentistry with the development of 3D-printed tissue. These advances in the use of 3D printing technology can not only improve the health and wellbeing of Australians, but open the doors to medical and dental part manufacturing, where individual customisation or small runs can be carried out with efficiency and confidence using reliable technology such as SLM Solutions range of selective laser melting systems.
Raymax Applications is the Australian distributor of SLM Solutions laser systems and metal powders.