Episode 345

345: Simple, Predictable, Digital Denture Workflows (With or Without a Scanner) - Dr. Wendy AuClair Clark (Covid Conference)

Published on: 15th October, 2021

Simple, Predictable, Digital Denture Workflows (With or Without a Scanner)

Episode #345 with Dr. Wendy AuClair Clark (Covid Conference)

Dr. Wendy AuClair Clark loves digital dentures. And according to pilot studies, patients do too! Going digital speeds up fabrication, cuts down chair time, and can be less expensive. It’s not just the dentist’s workflow that improves, but also access to care for the denture population. What's not to love? If you're still not convinced, Dr. Clark demonstrates how the digital denture workflow is easy, predictable, and very low stakes. For more reasons to try digital today, listen to Episode 345 of The Best Practices Show!

Main Takeaways:

There is no longer just one workflow. Any step can now be digitized.

Every single stage of your diagnostics is preserved with digital.

Printing is generally a faster, less expensive way to digitally fabricate.

Milling is usually stronger and more aesthetic.

Milled PMMA will minimize staining, porosity, and fracture risk.

You can reline, rebase, and repair milled PMMA dentures the same as conventional ones.

The average digital denture workflow is about 2.65 visits versus 5 for conventional.

With milled, there are fewer postoperative adjustments with digital versus conventional.

In pilot studies, patients preferred every aspect of digital dentures over conventional.

Digital can help close the access-to-care gap for older, edentulous patients.

One downside is there are only short-term studies on first-generation printing.

Quotes:

“I heard a lab tech, Josh Jakson from Evolve, who really laid it out as simply as I've ever seen. And it’s so true, that every aspect of digital dentistry can be put in one of three buckets: data acquisition, design, or fabrication. So, digital dentistry really is an easy thing. And you could take any aspect, so whether it’s making a CEREC crown, you scan for the acquisition, you design it, and you mill it. And it’s the same for digital dentures.” (03:44—04:09)

“The other thing that I like people to be aware of is that there's not one workflow anymore, that truly any step can be digitized. And so, if you want to do a whole analog workflow and digitize one step, that's fine. If you want to do digital start to finish, that's fine too. So, it shouldn't be as exclusive, I think, as we tend to make it sometimes.” (04:20—04:40)

“Printing, in general, is a faster, less expensive way to digitally fabricate, so the CAM portion of CAD/CAM. And milling is usually stronger and usually more aesthetic. But there are exceptions to every rule. So, this is just the basic blocks that they would fall into. Printing is going to be additive, so you're building it up. You have uncured resin that you're building in layers to create something. Milling is subtractive. I would say it’s like when Michelangelo had a block of marble and he chiseled out David. That's what we’re doing with our dentures. We’re chiseling out these PMMA works of art.” (05:06—05:41)

“For a milled denture, you can have a monolithic option. And they have a block from AvaDent, Ivoclar has a block as well, where basically the white and the pink are housed in the same puck of acrylic. So, it’s kind of like an Oreo, is how it was described to me by the rep, where they have the pink on both sides, and the white in the middle. And the mill is aware of where the pink and white sit within that puck. And so, it’s built in in the software to mill it out precisely. So, the teeth are white, the base is pink, but it’s all monolithic. There's nothing bonded, nothing individual. It’s a block of a denture. So, this is going to be your strongest and maximized tensile forces and functional forces. You could also have a bonded denture where you're going to have the bases milled, and then the teeth are bonded into the sockets.” (06:11—07:00)

“Alternatively, if you don't want to work through a specific company, you can design and rig up your own monolithic denture. And this is what I've done with a lot of my full-service labs, where you take your standard white puck of PMMA, mill that in whatever shade you want, A1, A2, A3, and then you just add some pink composite and customize that to add your tissue.” (07:05—07:26)

“The cool thing about milled dentures is they are made out of PMMA, polymethyl methacrylate, which is exactly what your conventionally processed dentures are made out of. So, that means if you have somebody that comes in with a milled denture that breaks, or needs a repair, or needs it relined, you treat it the exact same way you treat a denture. So, you don't have to invest in any reline material. You don't have to learn a new protocol. It’s all exactly the same. So, you can reline, rebase, repair a milled PMMA denture the same way you would a conventionally processed denture.” (07:48—08:16)

“The other cool thing about it is that the PMMA is pre-polymerized. So, basically, the chemical reaction goes, the exothermic chemical reaction, and then it’s pressed into a puck. So, you're eliminating all of the voids and the porosities and inconsistencies you may see with an injection or a press-packed conventionally processed denture. So, really, that's going to minimize some of the staining and some of the porosity, and it’s also going to minimize fracture risk.” (08:18—08:47)

“There are seven different types of printing. When you're talking about digital dentures, digitally fabricated dentures, you're really only looking at vat printing, which is going to be SLA or DLP. And there's not one that's better than the other, SLA or DLP. It’s going to depend on the type of printer you buy.” (09:01—09:20)

“The downside with that first-generation printing that we see, and they're now calling it first-generation printing, is that the materials are not tested very well. They were just FDA-cleared in 2018, so we don't really have many long-term studies, and certainly not a lot of long-term clinical data on them. So, typically, what I'm using them for in my practice is for short-term use. I'm using them for my interim dentures. If I'm doing an immediate denture and I'm really not comfortable with the aesthetics or with the centric relation record, I'll do a printed one as an immediate, and then it’s a low cost, low stakes replacement that I can go into the next round of dentures and have a nicer starting point.” (12:49—13:31)

“Some of the issues that we’re seeing [with first-generation printing] are that you have to be really good with your bonding technique when you add the denture teeth to the denture base. And so, we see issues with them fracturing and debonding.” (13:32—13:41)

“As recently as last year, in the fourth quarter of 2019, we came out with our first second-generation printed resin. This is available now through Dentsply. They call it Digital Lucitone, and it’s really the most aesthetic material I've seen yet, as far as printable resins go. This workflow to this material is super limited. The only SOP that's approved by the company right now is to design it on 3Shape, which is a very expensive lab software, and print it on a Carbon, which is a very expensive printer. So, we’re getting really nice results, but you're using the highest-end software in a highest-end printer to create this product.” (13:43—14:20)

“The other difference with this material is that there's not an SOP to print teeth with this base; you can only use carded denture teeth. So, basically, you're printing the denture base and then bonding the denture teeth into the sockets. Again, the protocol is really nice. You use the Dentsply pourable resin to lock the teeth in, and it’s a really nice cure. It’s a really nice feel. And again, very short-term studies, because this hasn’t even been out for a year. Shows pretty nice results with that product.” (14:21—14:51)

“Printed dentures are not PMMA. They're made of something similar to PMMA, but not quite PMMA. So, sometimes you can use your reline material and have it adhere, and sometimes it peels right out or doesn't stick at all. It usually has some sort of bis-acryl composite, so if you needed to do a repair, you could certainly use some composite and cure it. But it’s going to be a pretty short-term solution. And the philosophy is, these are almost disposable dentures. And so, if something happens to your printed denture, repair it real short term. Call your lab and have them print another one.” (15:47—16:23)

“When compared to conventional dentures, the way that I learned in dental school, and probably all of you learned in dental school, is a five-step painstaking process, starting with an alginate, making a custom tray, border molding with some sort of compound, and then using polysulfide or whatever record base is, all that. Lots of wax involved, and lots of very long appointments. And so, the biggest selling point for private practitioners is that all the protocols are shorter. The average digital denture workflow is about 2.65 visits versus five-something for conventional. So, you're cutting your appointment number in half, which is really great for our denture population because a lot of them are medically compromised, or a little bit older, or they have difficulty getting to the clinic.” (16:35—17:29)

“Right now, there's a serious access-to-care issue for edentulous patients and there aren't enough providers to make dentures for these patients. And it’s a really underserved community that are usually rural or in places where they don't have as many providers that provide the service. If we can make dentures accessible to those patients through digital, I think we’ll have done something really beautiful.” (17:32—17:54)

“There are not a ton of studies on [digital adjustment appointments]. There is one study that was relatively recently published, and we are actually trying to run a study right now with a few of our dental students at UNC, and what we’ve seen is that there are fewer postoperative adjustments with digital versus conventional. And that's particularly with milled, not with printed. With milled, we’re seeing roughly half the adjustment times.” (19:18—19:42)

“One of the other phenomenal things is that you're preserving all those records. And so, when you start doing a denture in wax, the first thing you do is demolish all the wax. So, you make a wax rim, you contour it, you spend hours and hours and hours, and then you melt it away to put the teeth on. With digital, you preserve every single stage of your diagnostics.” (22:20—22:40)

“There was a study done by Paola Saponaro out of Ohio State where they did a side-by-side study where the patients that had conventional dentures got digital dentures, and vice versa, and they compared the groups. And all the patients there liked every aspect of digital dentures better.” (22:43—23:00)

“The scanners are getting better and better and better, but there's still not really border molding because you can't pull that tissue down and scan it at the same time. You can only scan something static.” (23:48—23:58)

“If you do a wax rim, you are no longer melting away all of that work you did to carve your wax rim. And so, right now, you can see where those denture teeth fit in relation to where you put the wax rim. You can see where you scored the high smile line. You can see where you scored the midline. All of that data is there. And so, let's say your patient has some asymmetry that you want to correct with a tooth setup. Now, you can see in wax where you've built out that tissue support and you can make sure that your lab is putting the teeth in the exact same spot to give you that predictable result. So, again, we’re eliminating a lot of the lack of predictability with complete dentures.” (35:30—36:06)

“The benefits of bonded teeth is really going to be the aesthetics. And this is, I think, a prosthodontist thing, but a lot of people don't like the way the milled denture teeth look because they're more opaque than a conventional denture tooth. They say they're not as aesthetic. So, if you and your patient are concerned about the aesthetics of a denture tooth, you're going to want to choose a bonded option or have your lab customize it afterwards.” (36:15—36:38)

“For immediate dentures, this was my next-favorite solution. Because I think the only thing more terrifying than trying to insert a conventional denture and not knowing how to scan a fit is trying to insert an immediate denture and you have no clue where those teeth are going to be. They might be upside down, they might be backwards, and they might even be for another patient. But now, if you do a digital workflow, you can take a TRIOS scan of the patient’s preexisting dentition or take an alginate and scan that in. And now, we are using the patient’s teeth, not blinding them off the cast and arbitrarily guessing where the denture teeth go. We are now setting the denture teeth virtually, compared to landmarks that we have not ground away or lost, which I think is really cool.” (36:46—37:31)

“I think this is so cool — and this is coming from a prosthodontist — that the virtual facebow can now be as accurate as a conventional facebow. I'm not telling you to throw your facebows away. But you have another solution. If you can take a full-face photo with a patient looking straight forward — so, they have to be looking straight ahead. And it’s okay if they're canted this way or this way. But they can't be canted this way or this way. It has to be straight on. And you can have them tuck their hair behind their ears, if they have long hair, so that you can visualize their ears, where their condylar element would be. And basically, you can take that photo and superimpose it over the virtual articulator, and you've now done a facebow transfer. Which, I think it’s phenomenal. And this is just the 3Shape software that the majority of lab technicians are using now. And all you need for this is a full-face photo. So, again, there's no big investment of technology.” (38:22—39:20)

“When your patient comes in with a set of dentures, don't go back and start from alginate. Save yourself a chair visit. Save that cost of chair time. Save the patient a trip down the road and use that data. Even if the patient hates their dentures, you can find out why they hate their dentures. Is the tooth too long? Are the teeth too far out? Do they show too much pink? Do they not show enough pink? Whatever it is, if you take their existing denture and capture that data virtually, you have that to go from.” (41:47—42:14)

“If you have any cheap printer — and truly, the Anycubic right now was on sale, last time I checked on Amazon, for $260 . . . you can have your assistant scan the denture and print it on any printer. And now, you have probably the most accurate custom tray and record base that you could ever imagine. So, you can grind on this. You can add to this. You can take a wash inside. But if you can grind the occlusion away and take a fresh CR, it’s basically a very, very accurate record base.” (43:23—44:00)

“This is my patient that we did our insertion on, and I like to tell this story. He was one of the first patients I saw in North Carolina here, and I came from Atlanta where everybody wanted teeth that are the color of the background of this slide. And when they weren't this color, they made me redo them brighter. So, he came in and said he didn't like the color. And I said, ‘Well, if we go a little brighter, I don't think it’s going to look very natural.’ And he was like, ‘What do you mean, brighter? I want it darker.’ And I literally sat down and had to calm myself, because he was the first patient I've ever seen that wanted darker teeth, ever, in my 15 years of practice. But the great news is, if that were conventional dentures, we'd have to send that back to the lab, start over from tooth try-in, at least, if not MMR. But here, I call the lab and I say, ‘Hey, I'm sorry. I said I wanted A1. I actually want A2,’ and then they reprint a denture. And I get the exact same denture in a different shade in three days, and not going through any of the steps, and zero extra minutes of chair time.” (48:21—49:24)

Snippets:

0:00 Introduction.

2:28 A brief history of digitally fabricated dentures.

4:41 Basics of printing versus milling.

6:10 Options for milled dentures.

07:48 Benefits of PMMA (polymethyl methacrylate).

08:55 Printed dentures and recommended dental printers.

11:09 Limitations and downsides of first-generation printers.

13:43 Second-generation printed resin.

14:53 Dental students today have exposure to digital dentures.

15:46 Printed dentures are not quite PMMA.

16:24 Benefits versus conventional dentures.