This week’s question is regarding different types of 3D printer resin.

Dental 3D Printing Requirements

A dental technician reader asked about resins he purchased, but cannot 3D print on his 3D printer. These are resins specifically for producing temporary crowns, bite and surgical guide models. In the dental world, there are indeed specialty resins dedicated for these specific applications.

Note that dental resins have particular requirements beyond “normal” resins used for mechanical applications: they often require certain certifications from the regulators. Thus there is a market for such unusual materials. 

The reader also said the 3D printer they were using was a Photocentric Precision 1.5, a popular device that’s used for many purposes, including dental applications. 

Matching 3D Printer Resins

After some thought I realized the problem might be a mismatch between 3D printer and resin. The Photocentric Precision 1.5 is a bit unusual as far as resin 3D printers go, because it uses a different type of light source. 

Defacto Standard 3D Printer Resin Wavelengths

All resin 3D printers use photopolymer resin. This is a peculiar material type because when exposed to energy, typically directed light, it polymerizes, or solidifies. By ensuring only certain portions of the resin solidify, the 3D printer can construct a complete and accurate object.

Most resin 3D printers have light sources in the UV range and specifically 405nm. This is the most popular wavelength used in 3D printer photopolymers. As you might have guessed, you need to ensure the 3D printer’s light source matches the resin, otherwise no polymerization can occur. You end up with a vat of liquid photopolymer resin after printing, with no solid objects.

Photocentric 3D Printers

What kind of 3D printer is the Photocentric Precision 1.5? I looked it up on Photocentric’s site, where they list the specs for all of their resin 3D printer line. 

Buried in the specifications was the line: 

“Compatible resins: Daylight Precision Resins”

Well. This means the Photocentric Precision 1.5 3D printer is a “daylight” 3D printer. This essentially means it has a light source that does NOT provide 405nm energy, but instead uses another light frequency. This explains why the reader was unable to 3D print the third party resins. 

Photocentric produces machines of this type because they believe the light frequency allows for a more efficient process and flexibility in light engines. I’ve seen 3D prints from their equipment and they do produce excellent results. 

Why would a user of the Photocentric Precision 1.5 try to use alternative sources for resin? It could be that for this particular dental application very specific functional resins are required. Does Photocentric offer these resins? 

Photocentric Dental Resins

According to Photocentric’s site, they offer quite a few different resins for the device, including: 

• Dental Model

• Precision Hard

• Precision Castable

• Precision Dental Castable

• Precision Concept

• Precision Mould

• Precision Skin Safe

• Precision Firm

• Precision Model

None of these specifically say “surgical guide” or “bite model”. The description for each is: 

”Daylight Dental Model

Accurate, high resolution models especially for dental work can be created using Dental Model resin. Ideal for Orthodontic, study, and working models and created in collaboration with Dental Technologists to ensure optimal colour, feel and working characteristics.”

And: 

“Daylight Precision Dental Castable

Precision Dental Castable is ideal for creating highly accurate castable items such as crowns, bridges and partial denture bases. The resin has been formulated to burn evenly at regularly increasing temperature stages to reduce gas pressure in the cast and provide almost no ash content.”

Again, there’s nothing in the descriptions to directly match to the reader’s requirements. However, I’m no dental technician and perhaps these materials could indeed be used for those applications. But it doesn’t specifically say so. The reader should consult with Photocentric on this. The material descriptions could be the reason the reader decided to purchase resins elsewhere. 

Unfortunately I am unable to identify any other daylight-capable resins from other sources. There are plenty of 405nm resins for these applications, however. 

Choosing 3D Printer and Material

It appears there are only two options to go forward. Find a source of daylight-compatible 3D printer resins that do meet the application requirements (which could indeed be those from Photocentric). 

The other alternative is to first find the third resins that are required and then find a 3D printer that can use them. In some cases the materials will be tied to a specific manufacturer’s device. Unfortunately this could mean the purchase of a second resin 3D printer. 

The moral of the story here is that all things should be considered before purchasing a 3D printer. Does it have the ability to use the materials required? Are the materials required available? Have they been tested on this specific machine? 

Asking those and other questions early on can resolve issues that might occur after the purchase.