QCing Printed Nightguards From Gloss Trays? / General Resin Residue-Detection Strategies

[tuyere]

Hey folks,

We print a lot of Keysplint Soft nightguards- maybe 50-60 units a day- and have been having increasing issues with stuff getting cured without being completely clean. We're also considering making the jump to Carbon's new glossy-print cassettes to reduce post-processing work, but this will have the effect of making it even harder for techs to visually identify resin remnants on prints. I think it's mostly down to inexperienced techs due to a lot of turnover; they'll figure out good working practices sooner or later, but that doesn't help us now.

What strategies do you use to identify resin remnants on printed nightguards, where the finished parts are glossy enough for the gloss of liquid resin to be indistinguishable? What other practices to you use more generally for finding unwashed resin on parts that aren't primarily visually-based? I'm seeing techs look at parts under bright lights and use brush washing + compressed air to spot-clean parts, which shouldn't really be necessary with good working practices, ime, but I'm not their supervisor or manager.

 

[a3dl]

We do about 10/day w carbon. We actually use a toothbrush soaked in ipa to scrub inside then either airdry or bench dry before curing. My techs super aware of the supports sometimes lodging inside on accident. if you orbital shake them well enough with clean ipa all residue is gone.

 

[Affinity]

but I'm not their supervisor or manager.

Youre showing great initiative, Im sure their manager will reward you for all your effort.

 

[GermanEngineer]

We first wash briefly in a Tupperware container with IPA. Shake for around 10 seconds to remove any coarse residue. This is solely so that the IPA can be used for longer in the subsequent process.
After that we wash in the “RapidShape Wash”, which is identical to the “Straumann Wash”. The RapidShape Wash is a two-stage system with pre-wash and post-wash.
If you are washing different materials, you can change the two bottles of washing gel liquid very quickly using a quick release.
Both bottles also have an RFID chip, which means that the system automatically recognises which pair of bottles is connected and how often it has been washed.
The bottles can simply be refilled with IPA yourself and the counter reset. This means you are not forced to buy special material for a lot of money.
As I said, we have never had any problems with liquid resin or poorly cleaned prints.

 

[tuyere]

We first wash briefly in a Tupperware container with IPA. Shake for around 10 seconds to remove any coarse residue. This is solely so that the IPA can be used for longer in the subsequent process.
After that we wash in the “RapidShape Wash”, which is identical to the “Straumann Wash”. The RapidShape Wash is a two-stage system with pre-wash and post-wash.
If you are washing different materials, you can change the two bottles of washing gel liquid very quickly using a quick release.
Both bottles also have an RFID chip, which means that the system automatically recognises which pair of bottles is connected and how often it has been washed.
The bottles can simply be refilled with IPA yourself and the counter reset. This means you are not forced to buy special material for a lot of money.
As I said, we have never had any problems with liquid resin or poorly cleaned prints.

I've wanted to get a better print washing device for ages, but the price point for these systems is way too high for us to consider. How much did the Rapidshape unit cost you guys?
There's an enormous gulf in terms of price between the 'pro-sumer' wash units and the commercial (or especially dental) ones, which is frustrating. Right now we run Form Wash units, they're reasonably-powerful impeller-agitation systems that automatically raise and lower the wash baskets, which is nice because it lets stuff drip-dry and prevents alcohol-sensitive materials like nightguard resin from being forgotten in the wash and blowing past the validated workflow acceptable immersion times. They're like, 6-700 apiece? And then there's nothing else until you're paying almost 5 grand for the Form Wash L, which doesn't seem to offer a significant process improvement, just a larger tank volume. Something with jet agitation would almost certainly solve this issue quite handily for us, but post-processing is difficult to get management to invest in, from their perspective a shaker table and a tupperware full of alcohol is "good enough", so why spend the money?

 

[tuyere]

For the record, my specified workflow for nightguards is:

• Deplate nightguards onto a wire tray, occlusal side down, so resin has a chance to drain out before the wash. lly let sit for a minute or two.
• First-stage 'dirty' wash, 4 minutes, occlusal side down, no more than two layers of nightguards in basket.
  • If more than two layers, mix basket contents after 2 minutes, trying to put parts on top at the bottom afterwards.
• Second-stage 'clean' wash, 3 minutes, occlusal side down.
• Third-stage 'rinse', douse basket full of parts with totally fresh IPA using lab wash bottle, just enough to wash away residue from clean wash.
• Place nightguards occlusal down in a coarse mesh basket, then place basket in crossflow drying cabinet shelf (a sealed chamber I built that's inline with our fume hood extractor air duct, so air is constantly flowing over the parts and being immediately ejected to outside the building).

When I follow this, I basically never have to check my work, nightguards are consistently clean with very little spot-cleaning required. The fact that we're getting bad results is almost certainly down to people not following this workflow, and then also failing to QC their own work before it gets cured. I can't do anything about the personnel compliance part, so I'm left trying to fix this strictly through equipment or techniques that don't put any particular skill or compliance effort from techs. Not super hopeful about that working out, but hey, might as well try.

 

[mmbh]

For the record, my specified workflow for nightguards is:

• Deplate nightguards onto a wire tray, occlusal side down, so resin has a chance to drain out before the wash. lly let sit for a minute or two.
• First-stage 'dirty' wash, 4 minutes, occlusal side down, no more than two layers of nightguards in basket.
  • If more than two layers, mix basket contents after 2 minutes, trying to put parts on top at the bottom afterwards.
• Second-stage 'clean' wash, 3 minutes, occlusal side down.
• Third-stage 'rinse', douse basket full of parts with totally fresh IPA using lab wash bottle, just enough to wash away residue from clean wash.
• Place nightguards occlusal down in a coarse mesh basket, then place basket in crossflow drying cabinet shelf (a sealed chamber I built that's inline with our fume hood extractor air duct, so air is constantly flowing over the parts and being immediately ejected to outside the building).

When I follow this, I basically never have to check my work, nightguards are consistently clean with very little spot-cleaning required. The fact that we're getting bad results is almost certainly down to people not following this workflow, and then also failing to QC their own work before it gets cured. I can't do anything about the personnel compliance part, so I'm left trying to fix this strictly through equipment or techniques that don't put any particular skill or compliance effort from techs. Not super hopeful about that working out, but hey, might as well try.

I use form wash also. I think most labs don't put enough emphasis on cleaning the models thoroughly enough. If parts are tacky at all going into the cure then they aren't clean enough.

 

[GermanEngineer]

I've wanted to get a better print washing device for ages, but the price point for these systems is way too high for us to consider. How much did the Rapidshape unit cost you guys?

I'll send you the price in a message.
We have two RapidShape Wash and two RapidShape Cure. I was also put off by the price at first, when you compare it to the price of the non-commercial devices.
After I bought the first RapidShape printer, I took it apart a little before the first print to see what I had bought and how the 40kg weight came together. What I saw as an engineer was beautiful, high-quality German mechanical engineering, where no expense was spared. So I bought two more Rapidshape printers within 3 months.
Back to the topic of wash.
I saw this at a friend's house and was very impressed by how reliably it works and how much working time it saves. In addition, the washing processes that have been validated by the resin manufacturers.
When I got the first wash, the first thing I did was remove the housing to take a look inside. The wash and cure are not lightweight either. Here, too, I was impressed. Two high-quality hose pumps from industrial process technology are installed. Even then, the IPA for the clothes, laundry and nightwear is not mixed together. They are special chemicals. Resistant hoses for hose pumps are installed. The plug-in systems for quickly changing the liquids are from CPA. With this hose coupling, you can separate both hoses at the same time. And now the highlight. After the process, the product is dried. The dry air is passed through three very high-quality activated carbon filters. In addition to the two RFID readers and so on, in my opinion you get a lot for the money. They are not plastic boxes. Everything is made of stainless steel.
Of course it could be cheaper. But you should remember that they don't build millions of identical devices. But development and service have to be paid for somewhere. We forget that all too often. Moreover, the manufacturer also wants to earn something from the devices, just like we want to earn something from our dental products. As you can see or read, I am really convinced by the products. That's because I earn good money with them and don't have to worry about failed prints or anything like that. If a dentist or authorities ask, I can always provide evidence of validated processes.
I spent two days at the NextForm trade fair in Frankfurt a few months ago. I haven't found any alternatives for myself in this area yet. But I'm always open to others and new things. So if anyone has a tip, please let me know.