Application Spotlight: 3D Printing for Digital Dentistry & Clear Aligner Manufacturing

Digital dentistry — the introduction of digital technologies into the dental practice — is transforming the dental industry. One of the key technologies driving this transformation is 3D printing.  

 
3D printing has many applications in the dental industry, including bridge models, surgical guides and dentures. However, clear aligner manufacturing is one of the most common uses of dental 3D printing today.  

 
According to SmarTech Analysis, clear aligners are “perhaps the single highest volume application for 3D printing technologies in the world today.”

 
But how does 3D printing fit into clear aligner manufacturing? 

 
To answer that question, today we’ll be exploring the benefits of 3D printing for clear aligners, whilst looking at how dental professionals and labs integrate the technology into their digital dentistry workflows. 
 

What are clear aligners?  

 
Clear aligners are dental devices used to adjust and straighten teeth. Aligners offer an effective alternative to metal braces because unlike traditional braces, aligners are virtually invisible and can be removed when users eat and brush their teeth. 
 

The use of digital technologies to manufacture clear aligners is a perfect example of digital dentistry in action. The process typically begins with an orthodontist capturing an impression of a patient’s dentition with the help of a 3D intraoral scanner.

 
After scanning the patient’s teeth, the digital scans are used to design the desired position of the teeth. Once the final position has been determined, an orthodontist will plan the incremental stages between the current and desired teeth positions.  
 

Moving teeth is a complex process requiring several different aligners to be switched as the treatment progresses. The number of incremental models can range between 5 and 30 (on average, 6-10).

 
To create each aligner, orthodontists first need to produce moulds. These are then used in a moulding process called thermoforming. 
 

And this is where 3D printing comes in. 
 

It is estimated that the majority of clear aligners are currently produced using 3D-printed moulds. The key technologies enabling this are Stereolithography (SLA) and Material Jetting thanks to their high speed and accuracy. In addition to these resin-based processes, HP’s powder-based technology, Multi Jet Fusion, is also gaining traction. 
 

The benefits of 3D printing for clear aligners 

Patient-specific solutions 

Clear aligners are inherently individualised products. A set of aligners is custom-made to fit a patient, with each aligner being slightly different from the other.

 
This need for a high level of customisation requires a very flexible technology to make customisation viable. 

 
3D printing is the only technology that enables dental professionals to customise clear aligners cost-effectively. 
 

Unlike the milling process, which has been used in dental practice to create moulds, 3D printing doesn’t require expensive setup and tools. This means that 3D printing can produce highly complex aligner moulds without added cost. 

Mass customisation 

Traditionally, clear aligner moulds have been fabricated using a combination of milling and manual processes like trimming, resulting in a time-consuming and labour-intensive process. 3D printing accelerates the process by enabling a large batch of custom moulds to be produced directly from patients’ digital scans. 

 
For example, Stratasys claims that its J700 Dental 3D printer can produce up to 400 clear aligners per day. HP has gone even further, stating that its new customer, SmileDirectClub, will be able to produce 50,000 unique moulds per day using 49 HP Jet Fusion 3D printers running 24/7. This is roughly equal to 1,020 moulds per day for one printer alone. 

 
No other technology would be able to create that amount of customised moulds in such a fast and cost-effective way, other than 3D printing. 
 

Producing clear aligners at the point of care

Dental 3D printing enables orthodontists to produce aligner moulds in-office, saving both time and money. 

 
In one common scenario, patient intraoral scans are sent to the dental lab for modelling and treatment planning, then high-resolution digital files are sent to the dentist’s office where the staff will 3D print the moulds and fabricate the aligners. 

 
By taking this approach, a dentist can begin treatment in a matter of days instead of weeks. 

 
Furthermore, thanks to this digital workflow, aligners can be replaced much faster in the event that they are lost by a patient. With an in-office lab, the staff can use the digital file of the lost aligner, 3D print a mould and then quickly cast the new one — a process that can be done within several hours.