Around the World Perspective GentleWave Controversy & China Lecture Tour

What is the preferred method for endodontic disinfection? This question consumes the endodontic world and especially as it relates to GentleWave. Additionally, in a 2019 China Lecture Tour, Ruddle touches on the Chinese Dentist perspective and relays some insights of his overseas travel in a special RUDDLE SHOW “Community” segment.

Show Content & Timecodes

00:50 - INTRO: Recent Trip to Seattle
03:57 - SEGMENT 1: Controversy - GentleWave
23:25 - SEGMENT 2: China Trip
42:27 - CLOSE: Outstanding Cases

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Downloadable PDFs & Related Materials

Focus On
Minimally Invasive Endodontics
Apr 2014

Clifford J. Ruddle, DDS, discusses predictably succesful endodontics in the context of preserving healthy tooth structures...

Ruddle on the Radar
Jan 2020

Cliff Ruddle shares his candid opinions on the GentleWave 3D Disinfection Technology and its associated controversies...


This transcript is made available by The Ruddle Show in an effort to share opinions and information, and as an added service. Since all show text has been transcribed by a third party, grammatical errors and/or misspellings may occur. As such, we encourage you to listen/watch the show whenever possible and use the transcript for your own general, personal information. Any reproduction of show content (visual, audio or written) is strictly forbidden.

INTRO: Recent Trip to Seattle


Welcome to The Ruddle Show. I’m Lisette, and this is my dad, Cliff Ruddle. Today on our show, we’re gonna talk first about GentleWave and the controversy surrounding that. And then, we’d like to talk about your lecture tour that you recently took, to China. But first, I heard that you were recently in Seattle. Why were you there, in Seattle?


Oh, Phyllis – most of you out there know Phyllis, my wife of 52 years. She organized a family vacation for her side of the family, and she had family come in from Texas and Michigan. And then, she already has a brother, just south of Seattle, so, we stayed in Bellevue. That’s across from Seattle, across Lake Washington. And we had a lot of fun.

In fact, you didn’t ask, but I’ll just throw out there, for the international people, if you’re in Seattle, you’re gonna wanna go to the Ballard Locks. The Ballard Locks is how they get big ships from Lake Washington, down several meters, down to Puget Sound, and that’s the outlet to the sea, the ocean. So, you can watch those boats go through various locks. That’s good. We went to the Chihuly Museum. Would you tell ‘em a little bit about who Dale Chihuly is.


Well, I don’t know too much about him, but I have been to the Chihuly Museum there, and it’s one of my favorite places to go. The – as – how I remember it is, there was an inside place that had huge art glass sculptures. But then, I really like the garden – outside garden, too, where the art glass seemed almost organic, like it’s part of the whole – plants of the garden.


Yeah. It was fabulous. I – you couldn’t own enough Chihuly. But the problem is, he’s now well-known [laughs], and nothing is very inexpensive. Probably – one day was pretty rainy, so we went to Tacoma. And I only mention that because that’s the largest private collection of cars in the world, and it’s called the Great Car Museum. And you can find race cars, you can find every vintage of car that was ever made and what the technology was, that went towards each new generation. And that was quite an experience.


And I also heard you went to Pike’s Market. And I think we actually have a short video to show you that’s pretty interesting. Can we see that? [Video playing from 03:10 to 03:28]


Yeah. Pike’s Market’s pretty fun. Lots of energy, people from every – four corners of the world are present. You can hear all the languages, and the fish are flying. And, incidentally, that wasn’t a bad barbecue.


It seems like, actually, that – which is harder? To catch a slippery fish with one hand, or do a root canal? [laughs]


Wow! That’s kinda Zen. I think we’ll just go from there.

SEGMENT 1: Controversy - GentleWave


Okay. Let’s get started with our show. [Music playing]

GentleWave is one of the newer technologies, that has emerged in the past couple years, that claims to be able to clean both prepared canals and their related root canal system. Since it has been reported that the main cause of endodontic failures is microbial, we all understand the importance of 3D disinfection. The company, Sonendo, sells the disinfection technology that they call GentleWave. There are a lot of claims being made about the positive results a clinician can obtain, utilizing GentleWave.

But, on the other hand, there are increasing reports from doctors who are skeptical of this technology and question both its efficacy and safety. Can you tell us a little more about the GentleWave controversy and give us the Ruddle opinion.


Be happy to. You know, in most human endeavors, there’s the good news, bad news. Would you prefer the good news, first?




All right, let’s do the good news. The good news is, GentleWave claims, or Sonendo claims, to have about 650 endodontists who are end users. This is a growing number, not substantial, but it’s a growing number. And it is somewhat disruptive technology. Also, they have a limited number of [inaudible] tapers, perhaps 5, that show its ability to clean the minimally-invasively-prepared canal, whatever dimensions that might mean, and the root canal system, even declaring that the penetration of irrigants can go somewhere around maybe 1,000 microns deep, into the dental tubules.

So, this is pretty exciting, because, since I’ve been involved in endodontics, for over 45 years, we’ve always been trying – the Holy Grail treatment is to eliminate the root canal system, like the extraction. So, I don’t know if this is good news, bad news, but it does cost about $70,000, and that’s for the entry system. And then, of course, there’s the disposable handpiece, that is about anywhere from 75 to maybe $100, per patient. And so, even users are adjusting to quite an enormous expense, just on a per-patient basis. So, that would represent perhaps the good news.

The bad news is, it’s filled with some deficiencies, some disadvantages, and even some dangers. First, I’d like to talk a little bit about the platform time. It might take you 3 to 5 minutes to put the platform on, although I’ve watched several live dentals, where they’re doing it for 15 or 20 minutes. But I get it. [laughs] Experience is the mother of efficiency. So, the platform, not only is the time to assemble it, but there are reports from several people, where the platform could fail during treatment. And what happens is, the reagent can leak out. It can go intraoral, or it can go out onto clothes.

So, that is something that dentists report that is a little bit frustrating. It’s a little bit of a hassle. Another thing is, in fact, the actual disinfection cycle. In the disinfection cycle, it might take about 8, maybe 10 minutes, somewhere in there, maybe a little less. There’s a lot of people reporting differences, and this comes back to what we’ll talk about later. There doesn’t seem to be a universal protocol. But let’s just say, eight minutes. Well, during that eight minutes, you really need to stay in the room. You shouldn’t go make a phone call or do a quick check, because you need to watch the connection between the handpiece and the tooth, to make sure that isn’t failing.

Because, if that fails, again, reagent can escape, and, of course, you’re not disinfecting. So, those are probably just nuisance things, and you’ll get rich, someday, and you’ll be able to afford one in every room.




And you’ll figure out platforms and the Zen part of treatment, where you, mmmm, and you watch the disinfection cycle. You imagine bacteria being ripped out of tubules! It’s a thrilling thing to experience. I hope, someday, I can experience it, when we clean up more of the bad news. Well, let’s get into some of the more dangers or, certainly, things that are provoking. Hemorrhage. It’s almost, it seems like, from the reports, everybody that uses it experiences a vascular incident, at least on every tooth. And, if not every tooth, every two or three teeth.

And when – from watching several demos, I’ve noticed bleeding emanating up from the apical regions, presumably, and what you can tell is that there is a little bit of an accident. So, I’ve watched some of the clinicians, the Sonendo clinicians, use an astringent on a paper point, a hemostatic. And what they do is, go down and stop bleeding. They arrest bleeding.


Well, is bleeding – pretty much happens, every time?


We’re starting to sense that. You’ll talk a little bit more about some of the things you’re aware of, with the emails that come in. But it’s frequent enough that it comes up almost all the time. Now, okay. You can stop the bleeding. But I wanna know about the coagulum. This thick, ropy, black coagulum, which is the end game of hemostasis, means that that coagulum’s being left resident in the root. Because a simple – what I saw was a simple flush with a reagent, a little, hand-held syringe, and then, the went ahead and fit their cones and [inaudible] used a carrier.

That astringent is not going to be eliminated from the deep anatomy, certainly the preparation, the eccentricities off the rounder parts of canals, and even into the lateral anatomy, by a simple, little, hand-held flush. So, that is a concerning thing, the hemorrhage part. Let’s go and look a little bit further. We do have shape shifting. And if you think about shaping, we worked our whole lives to figure out a protocol where you pretty much knew, you know, negotiate the canal, catheterize it, and develop some kind of a shape, depending on your philosophy of treatment. With these more minimally prepared canals, they’re more parallel. And when they’re more parallel in the apical zone, that means we don’t have resistance form, to help hold our reagents, internally.

Also, when we don’t have resistance form, we have packing issues, because we don’t have, again, the resistance form to hold our gutta-percha inside the canal. So, the problem, then, with shape shifting, with – and shaping [inaudible] all over your [inaudible]




The shapes you’ve learned to develop is that you’re [inaudible] but beyond bein’ a [inaudible], which we all have [inaudible] – yeah. So, we got confirmation on that, is – no, really, what I’m saying is, the shapes have now been advocated by many different users, you know, protocols, to be one, two, or three millimeters short. And, of course, when we start to develop these short cases, we really wonder, ‘Did that plug of tissue in the apical region actually get pulled out and extricated and eliminated?’ Or, in fact, when we see the post-op film, and we see a 4-millimeter short case pack, then, we wonder, ‘Why didn’t obturation materials move into vacated spaces?’

Also, there’s quite a bit of pain. I’m skipping down to pain, but the pain could be related, in my mind, to inadvertently pumping reagents through the foramen. That’s like a sodium hypochlorite accident. Or the pain could be related to leaving a stump of vital, highly inflamed tissue, that you might wanna talk about [laughs] in just a moment. So, we have the shift shaping, we have the post-operative problems. But another problem that’s developed beyond GentleWave and Sonendo is this whole concept of minimally invasive endodontics, where there’s a great emphasis on tooth preservation.

Perfect. Let’s maximize remaining dentin, while still doing our job. And one of our jobs is to treat patients. So, when we have a tiny, little shape that we can’t introduce our armamentarium for three-dimensional obturation, then, we have to look in other ways. So, some people have gone to single cones. That seems to be the fad, single cones with bioceramic sealant. I had a good exchange with a Chinese dentist from Hong Kong, who was in my lecture recently, in Shanghai. And – make that Beijing. But, in any event, he stood up, and he had some things to say to me about the virtues of it.

Listen, I agreed with him. He’s developed a marvelous material. BC material is a repair [emphatically] material, but he could not argue with the fact that you can’t eliminate it in the retreatment situation. There are no solvents that it’s miscible in, nor do we have any mechanical way to completely remove it or eliminate it from the eccentricities off the rounder parts of canals. So, those are probably – hemorrhage, the shape shifting, the obturation and the [inaudible] pain, that’s what we hear the most about. Chat rooms are filled about – with this ongoing discussions, ‘What do you do?’, ‘What does this one do?’

And that’s all fine to compare notes, but that comes back to, the technology has some deficiencies, and then, the protocols are not accounting for how to maximize safety to our patients. Finally – this could be another whole lecture. Perhaps it will be another segment on The Ruddle Show, but, marketing. You know, it’s always normal for companies to be very enthusiastic about a new product launch. So, round of applause. We’re getting it rolled out. The thing is, let’s not misadvise the general public or endodontists.

I think it’s called exploitation. And what that means is, you can’t use the AAE’s website, in my opinion, to go into a diatribe about the new standard of care. The new standard of practice, they like to say, is GentleWave. No, it’s their standard, but it’s not my standard. When I introduced, with a group of about 4 or 5 people, back in the mid- to late ‘80s, the microscope, we didn’t call it the new standard of care. There was, like, 10 users. We did not call it the new standard of practice. There were still just 10 users. And even after we presented it, in 1995, to the AAE, and after that meeting in Chicago, 51 chairs voted, 51 to 0, to incorporate the microscope into everyday graduate programs, it still wasn’t the standard of practice or the standard of care.

So, that really sends an alarm out, across North America, when somebody’s claiming, ‘We are the new standard of care or practice.’ The other thing is the fear. The fear, they’re saying, is, ‘Did you know, Lisette, if you leave bacteria behind, you could face a class-action lawsuit?’ That’s kind of a provocative statement. It sounds like – it sounds like it’s screaming, ‘Buy! Buy! Buy! Because, don’t be sued.’ Well, come on! Listen, tens of thousands of dentists [laughs] have been trained, over the last decades, to appreciate the rational treatment approaches are available. Precise treatment techniques have been perfected, and success rates approaching 100 percent are attainable.

So, I hear that there’s a new way to clean root canal systems. It seems like a lot of us have been cleaning [laughs] root canal systems, for decades. But I’m happy, because some of them are filling their first lateral canal.


It doesn’t seem like just failing to eliminate the bacteria 100 percent, that that would be a lawsuit. It seems like, you do your best, and you try to get all the bacteria, and maybe a little bit is left, and maybe your body can handle that. But it doesn’t seem like there would ever be a lawsuit because too much bacteria was – I mean, where do you draw the line?


That’s the misinformation and the fear that they’re trying to provoke. And then, maybe I’ll just pick on one more thing. There’s many. But one of the last one was, is this so-called partnership between general practitioners and endodontists, and the encouragement that general dentists should actually be referring to a GentleWave user. This is like completely crazy, as you will explain to me, maybe right now.


Well, we do get emails, daily, wanting your opinion on GentleWave and giving you their experience, because maybe they have GentleWave in their office, and they’re using it. And this one email that we got from a endodontist in the Pacific Northwest, well, he says a lot. But mostly, a couple things --


He did have a lot to say [laughs].


-- yeah. Mostly [laughs], he says – a few things I’ll bring up, is, he says the company advertises that you can now do your endo in one visit, with GentleWave. Well, he says he’s been doing that for a long time, and --


Tens of thousands of us have done one-visit endodontics.


-- [laughs] additionally, it – I guess GentleWave promises that you will see anatomy that you never saw before, because you’re gonna see the lateral anatomy. And he said he’s been seeing this for years, just doing the – using the disinfection method that he uses. So, he’s not actually seeing more anatomy, and he’s actually not saving time, and – oh, excuse me. Le cramp. [laughs]


It’s okay. Sometimes, we talk about awkward things. We just cramp up. I mean, it’s just a crampy moment.


[laughs] But he also – you – you had mentioned that – that some – that they’re saying, ‘Don’t refer to an endodontist, unless they have GentleWave, because that’s the new standard of practice.’ Well, he says, in his email, that he actually has general dentists that will not refer to him, if he – if they know in advance that there – GentleWave will be used on their patients, because they’re so concerned about the pain and these issues, up here. So, yeah. I don’t know.

And regarding the shape shifting, he also talks about – well, right now, he says that mostly endodontists are using GentleWave. But when general dentists start using it more, he’s actually wondering if the preparation will become sloppier, because they’ll say, ‘Well, you know what? Actually, GentleWave will handle that. I don’t even really need to work on that, that – I mean, I can leave some bacteria behind, and it will be fine, because GentleWave will take care of it all.’


You know, you’re bringing up a good point, because at the end of the day, that brings us to our last bullet. Really, we don’t have a lot of evidence. We have a lot of case reports. I do a case, I’m excited, I show my first lateral canal, and I publish it. That’s not peer-reviewed science. That’s not evidence. So, they have about five peer-review papers, as an approximation. We should put an asterisk by it, because at least three or four of those peer-review papers are from advisors and advocates, and they’re on the Board of Sonendo.

But I wanted to share with the audience, there’s some really interesting things starting to emerge in peer-review journals, and I – I promise you, many to come [laughs]. But the first paper that we got, perhaps the first one with no prejudice or bias, is from the Toronto Group, January, JOE, 2019, and what they did is, they compared GentleWave with intermittent ultrasonics and some other stuff. But at the end, the conclusion was, there was no statistically significant difference between GentleWave and intermittent ultrasonics to remove the accumulation of hard tissue from isthmuses between MBs and MLs of mandibular molars.

So, we’re starting to see that, with all the good news, let’s just be patient and see what else comes up, before we run the flag up the pole and say we’ve achieved the mountaintop. We’ve summited.


Well, I can give a little different perspective from – maybe it’s a little more emotional perspective, being a patient who GentleWave was used on. I actually have had 3 root canals, and the first 2 I had about 10 years ago. At the end – after – that night, I could chew where I had the root canal, carefully. I had no pain, at all, and I had pretty rapid healing. Recently, last year, I had to have another root canal, and I --


And you went to the wrong person, didn’t you?


-- [laughs] I actually went to a different person, at first, because – for various reasons. It was – I couldn’t go to the original person, right then. But I was actually – had just learned that he had acquired GentleWave and had it in his office. And I was very excited to have this technology used on me, because I thought, ‘Well, for sure, now, all the bacteria’s going to be eliminated, and I should have no problems.’

I was a little concerned, because it was a way-back, upper molar. So, I was a little concerned about it – everything – all of the bacteria was gonna be got, if all the canals were gonna be found, and I was just a little concerned. Anyways, after that appointment, I have to say that, that night, I had the worst [laughs] pain that I – one of the worst pains I’ve ever had, in my life, discounting childbirth. But [laughs] --


You texted me, in Asia.


-- yes [laughs]. It was – I couldn’t even – it’s not like I couldn’t even chew on that side. I couldn’t really chew anywhere in my mouth, because even just bringing my teeth [laughs] in close proximity was super-painful. So, I ended up having to have retreatment. I had pain for a week. I ended up having retreatment, and I – there – there was a --


Were you on pain – were you on pain meds or antibiotics?


-- I did take – I did have to take antibiotics, because I had spontaneous throbbing and --


You were prescribed antibiotics.


-- yeah.




So, yeah. It was just a really tough experience, and I was – it was very discouraging. And I had to go – it ended up that a canal was missed, and it wasn’t cleaned, obviously, from the GentleWave. And I just -- anyways, I – it -- got it all taken care of, and after I had the retreatment, and GentleWave was not used in the retreatment, I immediately – my teeth felt great that night, and I could chew on it, again.


I’d like to make a comment. You know, sometimes in life, at least for my 40-some years of experience in endodontics, there is great anticipation that maybe some new technology can cover up deficiencies in primary training. And GentleWave isn’t, for me, good. It isn’t bad. It just is. And really, it’s the operators and training that makes -- the technology makes you potentially more than you are. So, the thing is, we’re seeing this out to 650-some colleagues, but they have vast differences in experiences. They have different training. They have different approaches, and there’s that old expression, ‘Who you are is where you were, when.’

SEGMENT 2: China Trip


[Music playing] A couple months ago, you had the opportunity of taking a lecture trip to China, where you visited Beijing, Shanghai, and Wuhan. Well, what a great experience to see how they practice endodontics in China and see what technologies are most relevant to them and also learn about their issues and concerns. Can you tell us a little bit about how dentistry, and endodontics in particular, is evolving in China?


Yeah. I’ll be happy to. It’s – it was a big honor to go to China. And I’ve been there before, but this was more of a tour than we’ve done in the past. And what I can tell you is, in those three cities, it kinda went like this. There was a large lecture, to several hundred people, and then, what I noticed was, they always wanted that day two. And in day two, I went to the hospital settings, where we spent time with just the professors, the chairman, and the faculty, and, of course, the residents. And they had some fourth-year dental students there as well. So, there was a good group of interaction. So, that was really fun.

In fact, before we get into that any further, I’d like to acknowledge some people, and maybe I’ll just pivot around here. Okay. So, these individuals, up here, except for Dr. Nathan Le, they’re all professors, and they run dental schools. There’s the Peking University, and then, there’s a Capital University. Those are the two in Beijing. And then, we have one in Shanghai and Wuhan, and they’re all there. So, I wanna acknowledge them, because those are the movers and shakers, and that’s what’s moving endodontics forward.

Down here, it’s a special call-out to Yu Lin, Professor Yu Lin, she’s at Peking, and Nathan Le, Dr. Nathan Le, who’s a dentist in Southern California. Nathan Le’s classmate organized our trip. So, I wanna acknowledge Yu Lin, Professor Yu Lin, and Nathan Le, for getting the Ruddles over to China and the three-city tour. And then, of course, we have a guy here named Daniel Nobs, and Daniel Nobs has been a friend for 25 years. He runs Dentsply Sirona’s International Education Center.

So, he goes around the world giving courses at conferences and national meetings and state meetings and local meetings, and he knows a lot about clinical endodontics. So, it’s fun to travel with him, and these are the people that made the trip possible.


Well, great. I think that we should let our viewers know that, while you are talking about your trip to China, we will have these photos rolling behind us. And if you miss any, don’t worry. You can see the whole China photo gallery on The Ruddle Show website.


So, let me give you a little social overview of my experience in China. First of all, there’s a lot of passion for dentists to do better dentistry. They really are hungry in China to do state-of-the-art. And, in fact, what I’ve noticed is, especially in the hospital settings, where most dentistry is actually taught and learned, a big presence of women in dentistry, I would say, even greater than what we see in the U.S. And I’m judging that across the 40 years of my professional life in endodontics. So, we’ve seen a big renaissance in that.

And then, of course, China is very anxious to use the best technologies, along with the best ideas, to deliver private patient care. So, that’s a little bit of what I noticed. I also noticed that there was a large discrepancy between, let’s say, private practice, outside the dental schools, and in the – actually the colleagues, and what’s being done in the university settings. It’s a big country. There’s a lot of people, we’ll talk about just momentarily, so you can see, there’s a challenge that lies just ahead.


Would you say the discrepancy is in terms of technology? Like between private practice and at a university setting?


Well, maybe I can explain it this way. In the United States, there’s roughly 350 million people, and there are 180,000 U.S.-trained dentists. That’s everybody. In China, you have 1.4 billion people, and you have the same, exact number of dentists, 180,000. So, the challenge I speak of is, how does a society that’s becoming – emerging rapidly into Westernized dentistry, how do we get healthcare out to all those people, with only 180,000? And they can’t all get to the universities. So, there’s lots of universities in the major cities, but of course, just like in the States, there’s the more rural areas, and there’s millions of people there that need to be treated.


And not the same technology that they have at the universities.


No, I think you would – I’m agreeing with you. I think you would find a big fall-off in technology, once you left the university. I have Chinse friends that are in private practice. And, of course, they have microscopes and CVCT, and they have all the whistles and bells that we have. But just like you leave some of these high-tech centers in the U.S. and get out into – somebody doing dentistry out in Nebraska or – name a state, and they’re not all gonna own microscopes and CVCT. In fact, we know statistically in the United States, only about six percent of the colleagues use microscopes, every day, in their practice.


Is that general practitioners?


That’d be general practitioners. Yeah.


Okay. Well, what technologies were they most interested in?


You know, what I noticed was, at the universities, they have everything that we have. So, they have CVCT, they have oral scanners, they have microscopes, they have motors to drive instruments. And probably the most – they love simplicity. So, that really [laughs] spoke to me, because anything I’ve ever invented, if it wasn’t simple, simple, simple, I didn’t really have time for it. Let the smarter, brighter people do that.

So, what I noticed is, they use WaveOne Gold. That’s what’s used predominantly in all the universities and the young residents. They love it, because it’s generally one, single file. With the files and the shaping of canals, though, comes the anatomical challenge. And that was kind of startling for me and somewhat humbling, by some of the anatomy that they talked about.


Well, can you tell me a little bit more about that.


Yeah. I mean, in the United States, you can ask an endodontist – depends on where you practice, but if you live on the West Coast, and we have a big, moving society, and people coming and going, and we have mixed communities. We have Asians and Haitians, and we have – we have all kinds of people, from all walks of life. So, we have Chinese communities. Well, in Chinese communities, there’s a C-shaped molar. Well, over there, it's 35 percent of all molars that present for endodontic treatment, 35 percent of ‘em are C-shaped molars. So, we’ll look at that a little bit more, in a minute.

They have taurodontia. And taurodontia, for those who aren’t familiar, it’s a really deep pulp chamber. So, you know, here’s the top of the tooth, and you start you window, and you’re drilling down and removing tooth structure, to fall into hopefully a pulp chamber. Well, guess what? In taurodontia, you’re to the other side of the world, and you’re still drilling, because the pulp chamber floor, sometimes, is half the total, overall length of the tooth. So, the occlusal table, the apices, you might drill down halfway, to get to the pulpal floor, and that’s where your orifices branch off and go to the various canals and the respective systems. So, they have deep pulp chambers.

So, you can see, looking through those oculars, it’s gonna really be important to get light down in there, and magnification, which is vision, so you can find all the anatomy on a pulpal floor. They actually have radix paramolaris. They have radix entomolaris. And that’s the typical, the mandibular first molars, and they have that little extra root. So, radix paramolaris is on the buccal, the little root is on the buccal, and the entomolaris is on the lingual. And these little roots are short, they’re thin, and they’re very tortuous. So, it’s really easy to strip [inaudible] during preparation. So, they take a very conservative preparation, to bring that canal in, appropriate for the root that holds in.


So, challenging anatomy, definitely. I did wanna go --


That’s why I practice, over here.


-- [laughs] I did wanna go back just for a moment to the technology that they’re interested in. Since we did just do a segment on GentleWave, I’m wondering what they think of GentleWave, there.


Oh! Probably, they’re – ‘member I mentioned, there was always that mixed setting. There was an all-day, big lecture, several hundred people. Then, we always went to the hospital to have a special break-out session. And the break-out session, across all three cities, all universities, you can weight three questions. What do I think of GentleWave? They don’t have it. They don’t use it. They’re not sure about it. They only read some of the stuff they hear in the United States. And, just so you’ll know, we only have maybe seven or eight peer-reviewed papers, and out of those seven, eight peer-reviewed papers, three or four of them are – maybe have conflicts of interest, because the author of the paper serves on the Board of Advisors for Sonendo’s GentleWave.

So, they understand that most of the evidence out there is hearsay and its case reports. But they are interested in GentleWave. The second thing that they frequently wanna know about is, what do I think of minimally invasive endodontics? And, of course, we’ve written many articles in the last two or three years about minimally invasive access cavities, minimally invasive shaping, and of course, good news, bad news, most human endeavors have both. They wanna know how you fill these more underprepared canals, because a lot of technology doesn’t fit. It’s too large to go inside these more conservative preparations.

So, they want to know, number three, what does Ruddle think about single cone, bioceramic sealer?


Hmm. You also told me about a really novel application they have for the 3D printer. Can you share with the audience a little bit more about what you told me.


Well, I probably have to go to the board, to do that.




Okay. Before we go into 3D printing, let me make a couple acknowledgements. I didn’t do this specifically for Shanghai or Beijing, but I’d like to do it for Wuhan, because the cases I’m going to show were done by the residents from Wuhan University. First of all, this is the fourth-year students, the post-grad residents in endodontics, and this is the Vice Dean, and right beside him is the Department Chairman of Post-Grad Endodontics. And that is that lady. You know, around the world, I’m known for catching sleepers. I would still like to identify people that don’t have their eyes wide open and appear to be maybe sleeping. Anyway, great group.

You can see Phyllis. Daniel Nobs, on the front row, and we’re getting ready to go. So, the students begin to give the – a case presentation. They begin to show me the things that they were doing at their school, and it was quite interesting. Let’s get right into it. Dr. Zhang, she wanted to show the classic, C-shaped molar, that we talked about earlier in the show. Remember, 35 percent of all mandibular molars that present for them to treat have this characteristic MB and then, it has the ribbon along the buccal, to the distal buccal, wrapping around to the DL. And you can see the cul-de-sac furcation on the axial section of the CVCT is towards the furcation, and that’s the lingual. So, this is exiting out to the lingual.

So, that’s the assignment. Now, what’s kinda cool is, they did the CVCT. They did oral scanning. And they modeled a tooth on their computer that was precisely the morphology of the molar that was going to be treated in the days ahead. And then, they went from that computerized model to an actual 3D-printed tooth, and that’s what we were talking about, earlier. And now, that gives you the chance to see the tooth, hold it in your hand, rotate it around, notice where it’s thin, notice that furcal side concavity, with a cul-de-sac furcation. So, there it is.

And then, they were able to access the tooth. They were finding the orifices. They show the shaping, and now, they’re showing the shape canals can be cone fitted, and here’s the cones, through that – I think it’s a plastic block of some kind. The material’s probably a polymer. But it’s clear, and you can see into it. And then, of course, going back to the clinic, the tooth is isolated, and now, what has already been rehearsed is now being performed. And you can see, the cone fits on that tooth. There’s the pack and the obturation, the photograph looking right down through the occlusal view, and you can see a very nice, obturated, C-shaped molar.

They’re all different, aren’t they? Notice the configuration here. There’s just one exit, but you can find every kind of variation, from sheets of apical foramina, all stitched together to make long ribbons, like flags flying in the breeze, or you can see, in this case, a more simple apical portal of exit. Well, you know, if you keep looking at this resident, and what she wants to talk about is morphology. And we talked about it earlier. I talked about taurodontia, C-shaped molars, radix entomolaris, radix paramolaris. Okay.

So, this is a focus more, though, just on the maxillary tooth. And you can see, you can have more or less fused buccal roots. You can see the more customary view we look at. And then, you can see three separate roots, but bridging between the MB and the palatal. And you can just keep looking at the anatomy and see bridging from the DB to the palatal, and you can cul-de-sacs and multiple portals of exit, all in through this area in here. You can see a classic horseshoe, like a C-shaped maxillary molar, and, again, more bridges, more multiple portals of exit. And you can see all this anatomy.

It’s quite exciting. And, of course, it speaks to three-dimensional disinfection and moving obturations around, to get a three-dimensional fill. So, those are some of the root forms that we’ve talked about, that they are showing. And, of course, if you take this right to the mouth, this is her pre-operative film. And then, Dr. Le is showing, in this axial section, you can see this kind of a star pattern, but – you can see all this anatomy. You can see all that anatomy. If we look at it again, in a more traditional way, that’s what we’ve seen for decades, right? Six canals, five canals, and a lot of files in there, and sometimes it’s hard to know which file’s going into which hole.

So, there’s little tricks. We can put Hedstrom in one, put a reamer in another, put a file in another one. So, we can differentiate where the files are, inside the tooth. So, apex locators are also useful. She pointed that out. And then, of course, she’s mapping out very clearly, so when we look at one, single image, both images together, you can see the one’s on the palatal side, and the three orifices and the related systems on the buccal side. So, she was pretty proud of this tooth, I might add. And she’s fitting cones, and then, she’s obturating. And you can see that star-shaped pattern in the floor of the pulp chamber of the tooth she just created.

In China, they go right on, as residents, they use 3D printing, and they’ll actually make a model for the restoration that can be delivered and seated to do cuspal protection, so we don’t entertain a longitudinal fracture, radicularly, over the life of the patient. So, the post-op films, sometimes, in these really complicated, multi-system teeth, it’s a little bit discouraging, because it doesn’t really show the whole effort. You know, six systems, and they kinda look like there’s some superimposition, and we have some stacking up of roots over roots, but there’s a pretty tightly packed second molar, all six systems.

So, at the end of the day, there was a little celebration. The Dean came down and graced us with his presence, really nice guy, and he's leading his faculty and his professors and his students into a bright, new future. I hope you’ve enjoyed a glimpse of the China show.


Well, it sounds like China has a pretty bright future ahead of them. That thing with the 3D printing seems like a brilliant idea, well, to me. But I’m wondering, maybe 3D printing, with all its potential, will guide residency programs, going forward.


Absolutely. 3D printing is changing – or has already changed, in the last decade, how we do a lot of things, access cavities. 3D printing’s been used for surgical access to apical segments. It’s been used for lots of applications. But it’s interesting. Already, we are moving beyond that. Like, for an example, talking to an implantologist, yesterday, and endo has this as well. But maxillofacial certainly has it, and so does the discipline of endodontics. And it’s X-Nav.

And in X-Nav, you know, you have a CVCT, like you have in sleeve guides, and the 3D printing. You have the oral scanner. So, you have the same technologies. What’s improved is the software. So, now, they have software packages where they do algorithms, and instead of making sleeve guides in 3D printing, those extra steps, they’re now all eliminated, because, with X-Nav, there’s a monitor. And you can position your handpiece, and it’ll tell you how to angle your handpiece, X, Y, Z, and also the depth of the drill.

So, probably all this technology is simply helping everybody around the world think about things and outside of the box. And it reminds me of Steve Jobs, when he said, ‘Let’s go invent tomorrow.’


Well, all that sounds really interesting. So, that pretty much does it for our China segment, for today. Again, if you want to see more photos from the China trip, that were going behind us, or if you missed any, feel free to go to our website, and they’ll all be there. [Music playing]

CLOSE: Outstanding Cases


Well, that’s our show for today. Now, I’d like to leave you with a little glimpse of some fabulous cases that were done by international colleagues, and these results were obtained, worldwide. What you’ll notice is flowing shapes. The shapes are appropriate for the roots that hold them. There’s evidence of disinfection, and you’ll notice filled root canal systems.


And incidentally, it’s very interesting to point out that none of these cases were done with GentleWave. So, what conclusions can we draw from that?


Fundamental’s still win it. You know, the conclusion you can draw is, when you have such shift shaping, with the GentleWave model, where it’s work-to-length, like traditional. Then, it’s work one millimeter short, now we’re seeing evidence of two and three millimeters short, the cases you’re noticing, it’s still fundamentals that win every endeavor in humankind. And what I mean by that is, we still wanna negotiate to the terminus, because we’re not looking for an anecdotal, sometimes event. We’re looking for predictable results. See ya at the apex. Or, as my Italian friends say, ‘Ci vediamo all’apice’.


Image Gallery: Beijing

Image Gallery: Shanghai

Image Gallery: Wuhan


The content presented in this show is made available in an effort to share opinions and information. Note the opinions expressed by Dr. Cliff Ruddle are his opinions only and are based on over 40 years of endodontic practice and product development, direct personal observation, fellow colleague reports, and/or information gathered from online sources. Any opinions expressed by the hosts and/or guests reflect their opinions and are not necessarily the views of The Ruddle Show. While we have taken every precaution to ensure that the content of this material is both current and accurate, errors can occur. The Ruddle Show, Advanced Endodontics, and its hosts/guests assume no responsibility or liability for any errors or omissions. Any reproduction of show content is strictly forbidden.

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