Monday, June 5, 2017
If you are managing a dental laboratory or practice, additive manufacturing is no longer a decision that can be postponed. With many new 3D printers being released constantly, the market continues to expand at all levels.
But for the first time, several 3D printing solutions offer a way to make digital dentistry an affordable, no-nonsense business choice to improve patient care, quality, and outcomes; broaden your product and service offerings, through surgical guides, retainers, aligners, orthodontic arches, crown & bridge models, and more; and reduce material and labor costs significantly through streamlined digital workflows.
What’s involved in integrating 3D printing into your business? What are the different technologies on the market? Why do some printers cost less than $5,000, and others $80,000+?
In this guide, we’ll look at the digital workflow, the different technologies and all the aspects you should evaluate before investing into a 3D printer.
The Digital Dentistry Workflow and Prerequisites
Every dental product that can be 3D printed follows the same basic workflow involving these steps. Adapting a digital workflow is an absolute must before you can introduce additive manufacturing into your business.
Scan
Every dental product that can be 3D printed follows the same basic workflow which involves scanning, designing, printing and preparing.
Like traditional dental product fabrication, digital production requires information on the patient anatomy. The simple difference is that data on the patient’s dentition can be collected digitally, with an intraoral scanner, removing the need for alginate impressions. Alternately, desktop optical scanners can be used to scan manual impressions or plaster models. For treatments that require patient osteotomy, such as implants, an additional dataset needs to be collected using CBCT scanners.
Design
Patient anatomical data is then imported into dental CAD systems, where treatments, prosthetics, and other dental products can be designed. The specifics depend on the treatment, but typically the design process is similar to traditional workflows, done on a computer. With digital design, treatments can be created with increased ease, precision, and care. After the treatments are designed, models can be exported for manufacturing.
Print
In order to physically realize a digital model of a dental product, 3D models are uploaded to the 3D printers, which then solidify the object layer by layer, forming the shape of the dental product with digital precision. For 3D printing dental appliances and models, smooth surface finish, fine details, high precision, and advanced material properties are key ingredients of successful prints.
Prepare
Once the models are 3D printed, there are often a few post-processing steps before a product can go back to the patient. For the most common resin-based technologies, all parts must be washed, dried, polished, and post-cured. Depending on the particular product, assembly with prefabricated accessories might also be necessary, such as metal guide tubes for surgical guides.
Required Resources
Intraoral scanner or desktop optical scanner: Allows you to replace manual impressions with fast and accurate digital impressions. Intraoral scanners are used in the dental practice to capture scans directly from the patients. Desktop scanners are used to scan PVS impressions or stone models, and are recommended for dental labs.
3D printed surgical guides enable quick and high-precision implant placement for just $2-5 per guide.
Dental CAD software: Allows you to process scan data to design treatments, prosthetics and other dental products, and export them as 3D models for milling or printing.
Optional Resources
CBCT Scanner: Allows you to acquire patient osteotomy. This is only required for select applications, such as for creating surgical guides for implants.
Technologies
Today there are three common technologies to create polymer-based dental products. Each of them cures photoreactive liquid resin with light to form very thin solid layers that stack up to create solid parts.
Stereolithography (SLA)
In stereolithography, a vat of photoreactive liquid resin is selectively exposed to a laser beam across the print area, solidifying resin as it goes along. The most common system in desktop 3D printers is inverse SLA, where the laser is directed through the transparent bottom of the resin tank. Stereolithography is highly accurate, offers large build volume and a wide range of materials. Thanks to the small footprint, simple workflow and by far the lowest price desktop SLA printers are an ideal choice for both dental labs and practices.
Digital Light Processing (DLP)
Digital Light Processing works similarly to inverse SLA but uses a digital projector screen to flash a single image of each layer across the entire print area at once. DLP printers offer a wide range of material options, but a small build volume and a substantially higher cost than desktop SLA.
Material Jetting
Material Jetting (PolyJet and MultiJet Modeling) 3D printers work similarly to inkjet printing, but instead of jetting drops of ink onto paper, they jet layers of liquid resin onto a build tray and cure them instantly using UV light. Material Jetting technologies were the most common in the dental industry a few years ago, but with the appearance of compact, lower cost SLA and DLP systems they’re now only worthwhile for a few specialized large dental labs. These systems have a high throughput, but a large footprint and a limited range of applications due to the costly, proprietary materials.
Technology Comparison
Digital Light Processing (DLP)
- Pros: High accuracy, Wide range of materials, Desktop footprint, Easy to use
- Cons: Expensive machinery, Small build volume
- Price: Starting at $12,000
Material Jetting (MJP, PolyJet)
- Pros: High throughput
- Cons: Expensive machinery, Limited material options, Large footprint, High maintenance
- Price: Starting at $35,000
Stereolithography (SLA)
- Pros: Great value, High accuracy, Wide range of materials, Desktop footprint, Easy to use
- Cons:
- Price: Starting at $3,500
For a deeper insight into the different technologies and digital workflows, we recommend watching this webinar by Dr. Michael Scherer DMD, MS, APC.
Evaluating 3D Printing Solutions
Accuracy and Precision
Guaranteeing high-quality final parts is the most important concern with any part made at a dental practice or lab–hence why accuracy and precision of 3D printers are major concerns. Accuracy is the closeness of a measurement to the true value. Precision measures the repeatability of a measurement–in other words, consistency of results over a batch of parts. For dentistry, it is imperative that both an acceptable level of accuracy and a high degree of precision are achieved.
3D printed models provide high accuracy as they eliminate numerous steps, and possible errors, from the manual process.
It is a common misconception that there’s a direct relationship between the specifications of a 3D printer–such as resolution, layer height, laser spot size or pixel size, and the accuracy of final parts. Resolution is simply the smallest feature that can be printed in a particular plane, and a lower layer height might give you a smooth surface finish, but it does not mean that you have an accurate product.
Accuracy is dependent on the 3D printer, the material, the print settings, the calibration of the machine, and how well these building blocks are integrated. Consequently, a printer can be more accurate with one material than another–which can be perfectly fine, as long as it’s in between the clinically acceptable limits for the specific use case. For example, crown and bridge models require superior accuracy to fit restorations and removable dies, while orthodontic models for vacuum-formed appliances are less demanding.
To evaluate if a 3D printer provides high enough accurate for your application, don’t rely on marketing or technical specifications. Always inquire with the manufacturer for clinical accuracy studies and real scan data of printed parts. Even better, ask for a sample part of your own design that you can measure yourself against the original design. This is something Formlabs and other high-quality 3D printer manufacturers are happy to offer.
For more information on accuracy and precision, we recommend reading this white paper, and an independent study comparing the accuracy of three popular 3D printers.
Ease of Use
In order to be able to take advantage of new technology in your dental business, your team is going to have to learn how to use a new piece of equipment and maintain it on a daily basis.
First, try to get a sense of the learning curve that will come with a new 3D printer. In some newer printers, you will find user-friendly design and user interfaces, which will help you get printing straight out of the box. Other printers can be much more complex to get started with, some requiring a service technician to spend time on-site to set up, tune, and calibrate the machine.
Another major consideration is everyday interactions and maintenance once the printer is up and running. Automatic resin dispensing can make a big difference keeping a low-maintenance production environment but is only available on select SLA machines, as well as material jetting printers. Easily switching between materials can help make a single printer useful for many different applications, which is where SLA or DLP printers with removable resin tanks and build platforms can offer a user-friendly solution.
Materials
Professional 3D printers are some of the most versatile tools found today in dental labs and practices, and the key to their versatility are dedicated materials. Various dental applications have different requirements–some have to be sturdy and machinable, others require biocompatibility, or look transparent for aesthetics.
One the first things to consider when evaluating your options is if a given 3D printer is capable of printing the dental product(s) you require. Some 3D printers work with proprietary materials, in which case your options are limited to the offering of the manufacturer. Others have an open system, meaning that they can use materials made by 3rd party manufacturers. However, in this case, it’s important to make sure that the printer model is suitable for the specific application, and that it can print parts with a clinically acceptable quality and accuracy.
The list of available applications varies by printer model. Most 3D printers can produce orthodontic models, surgical guides, or castable/pressable restorations, while advanced models can manufacture a range of dental products from highly accurate crown and bridge models to long-term dental applications like splints, night guards or dentures.
Manufacturers are releasing new materials on a regular basis, so there’s a good chance that the printer you buy today will become capable of creating an increasing variety of dental products in the near future.
Speed and Scalability
In thinking about speed and scale, remember to find the most cost-efficient way to power the production you need, and consider how you’ll implement production in your business. Finishing a build full of prints within an hour sounds enticing, but it may be more beneficial and economical to balance cycle times with how your business runs. Running two prints per day on a batch of machines, and simultaneously finishing a set of parts only twice per day, often makes more sense than having a technician constantly switching out parts from a printer all day.
Production with multi-machine print cells often enables more affordable up-front costs than larger-format machines. By buying one low-cost desktop machines at first, businesses can test out production methods before ultimately scaling up production. And, as they scale, they can simply increase the number of printers they use when demand requires it. This provides the opportunity to pay for the production you need, only when you need it, rather than making large long-term investments in a market that’s rapidly evolving.
Print cells also offer additional benefits beyond cost-effectiveness, including lowering risk through redundancy. If one machine needs servicing, production can be balanced across the rest of the print cell.
Return on Investment
Most importantly, adopting new technology needs to simply make sense for your business. Remember to consider:
- Up-front costs, which could include not just the machine cost, but also training and setup for larger-format machines, as well as, potentially, software.
- Running costs, which are best estimated with per-unit material costs.
- Servicing & maintenance costs, which can sometimes be compulsory and account annually for as much as 20% of the cost of the printer.
These will all have a direct impact on how fast you can make a return on investing in 3D printing technology. The good news is that with smaller format, low-cost machines that offer high-output quality, it’s now possible for dental labs or even practices to make their initial ROI within months.
Conclusion
Much has changed since the first desktop 3D printers became available for the dental industry. While a few years ago 3D printers were only affordable to the largest dental labs, now they are more and more common in labs and practices of any size. So why should you invest in a printer that costs less than $5,000, or one that’s $80,000?
Well, if it were this simple, there would be no need for this guide. Consider all the factors above and the needs of your lab and practice. Different solutions might be more suitable for some business than others. Depending on the application, desktop printers can produce dental products with high accuracy, similar or even better than those made with traditional industrial 3D printers. Make sure to do your research, evaluate actual parts, and avoid paying a hefty premium.