For many years, our team has been extensively involved in investigating how to significantly improve existing endodontic disinfection methods. Clinically, disinfection protocols should encourage debridement, the removal of the smear layer, and the disruption of biofilms...
Research Methodology and Q&A Important Research Considerations and ProTaper Q&A
This show opens with a little promotion of The Ruddle Show website and social media platforms. Next, Ruddle will discuss research methodology and how to avoid some common pitfalls when conducting research. After, Ruddle does another Q&A segment, this time focusing on questions from Chinese colleagues following the launch of ProTaper Gold in China. Stay tuned for the close of the show where we will reveal the best and worst of The Ruddle Show and Endodontics in 2020!
Related Materials & Show Notes
Endoactivator Research Addendum. Summary Of Supporting References: Ongoing Clinical Studies & Publications
In the United States, alone, more than 100,000 dentists perform tens of millions of operative, restorative, and reconstructive procedures on an annual basis. Certainly, these dental procedures are primarily directed toward eliminating carious lesions, esthetically restoring teeth, and functionally moving patients toward optimal oral health...
Many times over several decades I have described various concepts, strategies, and techniques for shaping root canals. Although the concepts and strategies have essentially remained the same, the techniques have evolved...
On a cold winter's night this past January, I had dinner at the Hotel Royal with a group of endodontists in Amman, Jordan. Sitting to my left was Dr. Edmond Koyess, my longtime friend who is the Department Chairman of Endodontics at the Lebanese University in Beirut, Lebanon...
Since the beginning of endodontics, every decade has witnessed controversy. Currently, there is ongoing debate regarding the concept of minimally invasive endodontics (MIE) as it clinically relates to preparing any given access cavity or canal...
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: The Ruddle Show Website
Welcome to The Ruddle Show. I’m Lisette, and this is my dad, Cliff Ruddle. Today, we’re shooting our last episode of Season 3. So, are you excited about it?
Very excited, because every ending has a new beginning!
So, before we start the show, we wanted to take a moment to promote our website and our social media platforms. You can follow us on Twitter, Facebook, Instagram, and YouTube. And we’re currently trying to be more active on these platforms, so do follow us. At the end of this segment, we’re going to put up some QR Codes that you can scan with your phone, to follow us very easily. And so get your phones ready. Up till now, you have not been very active on social media, have you?
I’ve actually avoided social media like the Plague.
But let me explain why. Those of us who teach, I think all teachers know this, but there was some pretty sage advice that came from 450 BC, just a short period ago. It was from Confucius. And what he said is, and we would be wise to remember this, as we think about teaching, “I hear, I forget. I see, I remember. And I do, and I understand.” So what that means to me is, we have gone out historically, instead of me being on social media, we’ve done the miles. We’ve done the flights. I think I’ve mentioned several times, 5 million miles, up to – through 2018, all lecture related.
So by going out, you can actually work with people, shoulder to shoulder. You can guide their hands. They can see you do something live. You can see them. We can look at results, and they really get it. So that’s the superior way to learn. But we’re in COVID. So with COVID, all that has shut down, and of course, a lot of people are struggling, especially the young dentists. They want to get into study clubs. They want to start going to meetings. They want to continue their education, even while the students lost about half their last year. So social media is something that I realize I need to get better at, and I have a lot of people around me that know a lot more about it than me. So this morning, I just fleeted.
[laughs] And now, explain what that is.
Hell, I barely know!
Apparently, I know you can tweet, because I’ve been doing that recently, to try to stay connected. But I guess fleeting is, the message goes up, but in a short period of time, it’s taken down. So your son, my grandson, he said it would be very good for what I say, sometimes very controversial, to be taken down quickly.
Okay. That’s the story thing they’re doing on Twitter, now?
I – okay. Well, our website is also coming along really well. All the episodes that we filmed, the 3 seasons, 30 shows, are all there to watch.
Our viewers are increasing!
Yes. We have transcripts of, so far, every show this season. So that will be very helpful to our – our viewers who speak another language. Okay. He’s drawing a picture. I’ll just keep talking. And we also have bios of ourselves and our cast members. And – and what does that say? “Views”. Our your – our views are going up?
Yeah. Views are climbing [with emphasis], like a plane!
We also have Show Notes that correspond to each episode of The Ruddle Show. Do you want to say something about the Show Notes?
Yeah. I want to acknowledge your daughter. [laughs]
What? You mean, your daughter, [laughs] my sister. [laughs]
Whoa, yes, uh-huh. That’s why we fleet, see? Those things get taken down quickly. Lori, your daughter --
[laughs] My sister [laughs].
-- and my daughter, her sister, Lori, has been with us for about 25 years, so she knows a lot about endodontics and the education of it and the commercial side of it. And what she’s doing is – it was her idea. I never – I just thought we’d do shows, you know, like, boom! Done! She said, “No, there needs to be more to it. When you do something, or you have a guest on, it would be nice to have actually Show Notes, to drill down a little deeper into the content” you and I are talking about or delivering’ So maybe you can tell us a little bit about what Show Notes might look like. And you might want to ask them if they even know about Show Notes.
Okay. Well, they are on our website. When you go to the specific show, you’ll see the Show Notes that you can click on. And if you kind of are doing a lecture or teaching something, we always will have the articles that go well with that lecture. We have links to Just in Time videos on our website. If we have a guest, well, there’s their bios. But sometimes there’s extra photos and just some other miscellaneous information. And we want to make the Show Notes fun. So stay tuned, because we’re – we might have bonus footage in the future or maybe some cast perspectives. So we’re excited about that.
If you want to make a comment or ask a question, there’s a space to do that on our website. And if you have any trouble navigating the website, just let us know. Send us an email, and we’ll try to fix the problem, because we want it to be fun for everyone. And we don’t want you to struggle. So --
So, we started in January. This is December. And 30 shows done, plus those 2 specials, so, we got a lot to do, still.
-- yeah. And we’re starting Season 4. When we’re done shooting this episode, we’ll get started on Season 4.
We have some great content, too.
Yeah. We already have a lot of ideas for future shows.
And our next – the first episode of Season 4 will launch in February of next year. So, that’s that. The QR Codes will be up in a second, and scan them to follow us, and let’s get on with the show!
SEGMENT 1: Research Methodology
So today, we wanted to talk a little bit about research. When conducting research, it’s important to develop a sound methodology to test your hypothesis.
I’ve heard you, over the years, commenting on others’ flawed research, whether it be too many variables, no clear protocol, no control, or maybe just a general lack of knowledge. Further, research needs to be unemotional, and the researcher needs to have an open mind, not manipulating the research to a desired outcome. And importantly, research experimentation should be able to be duplicated, to make results meaningful. So this is what we want to talk about today. And I think a good place to start is maybe for you to talk about your graduate thesis that you did and how you went about it.
Well, let’s not make it too much about me. But one thing about Harvard that – I got – I applied to four programs on the East Coast, and I got into all four of ‘em. And I chose Harvard for a variety of reasons. But Harvard really did emphasize that we had to do formal research, for about a year and a half, because you get there, and you take six months to figure out what you even want to do. And then you want to do something that’s meaningful. A lot of people don’t know what to do, and all of a sudden, they’re doing something, and you’re into a year and a half or two-year project, and you hate what you’re doing. So, you want to do something meaningful. And then, ideally, you’d like to do something that will benefit clinical endodontics and maybe even me.
So, I went to Harvard, and they had a fabulous, fabulous opportunity to do all kinds of research. I went to Boston for one reason, primarily to learn warm gutta-percha with vertical condensation. So, I liked the vertical condensation of warm gutta-percha. That was a Schilder technique. My mentor, Al Krakow, was Schilder’s second student. He was in that class with Joel Dunsky, second class. So anyway, it all started with the research. So, I’m pretty proud of this, and I hadn’t looked at it for like about 40 or 50 years, until this show. And I realized that we did some pretty cool stuff.
I did mine, as I said, on the adaptation of warm gutta-percha to vertical condensation. But up to that time – listen carefully – different obturation methods had been examined, using visual, visual inspection, clinical, radiographically, histology. They used dyes, they used isotopes, they used the light microscope. And that’s all that had been done to utilize leakage studies, and how does gutta-percha seal. So, we thought there was a real good opportunity to use the optics characteristics of SEM. So, scanning electronic microscopy. So, that’s what we did.
We looked at the adaptation. We were looking to primarily see what is the homogeneity of the gutta-percha, from orifice to terminus? We wanted to see ramifications. Could we move warm gutta-percha into fins, cul-de-sacs, loops, anastomoses, lateral canals? And so, that was that. And then we also wanted to look at them, and – that’s another whole research project, because you have to figure out how to split teeth. And so, we had to section the teeth, three times in the – so, I – so, we opened up the teeth. We had some controls, where we didn’t open them up, so we could just look at them and split ‘em. Cliff never touched them. The rest of the teeth were all accessed. We cleaned them, shaped them.
We had to develop a protocol for shaping. I followed the Schilderian Protocol for shaping, at that time. It was logical. And then, of course, you have to make sure, how often do you irrigate, what’s the concentration of the irrigant, what’s the temperature of the irrigant, what’s the frequency of irrigation, every other file, each file. So, all that has to be developed. And then, of course, we scored the roots. If I scored them too deep, I got into the gutta-percha, and I had to throw the sample away and repeat it. So, the trick was to score the tooth, externally, deep enough that you could just barely start to see the gutta-percha with your eye, with a light microscope, because teeth are translucent.
And then, that would help us either mechanically freeze fracture them or fracture them through dunking them in liquid nitrogen, at minus 250 degrees. So what we could look at is not only teeth that Ruddle didn’t do anything with, just to look for portals of exit and anomalies. Then there was another group we looked at, externally only, to look for lateral canals and multiple apical foramina. We saw many. And that was very exciting. And then, of course, when you fracture teeth, we’ve learned – we learned that when we mechanically fracture them, we produced more artifacts -- we induced fractures – than, say, if you quenched it. Because when you quenched it, everything was frozen instantaneous, so there was no gutta-percha pulling off the walls or sealer delaminating from the gutta-percha.
And we saw that we had wall-to-wall gutta-percha. That was really cool! And then, we noticed that the sealer interface between gutta-percha and dentin was on the order of seven, eight, nine microns. So we used the [laughs] – I guess when we looked at it recently, it was pretty bizarre. But we used an SEM machine. It was a --
And I think Harvard was – these were not – these SEM machines just weren’t everywhere. Harvard had one, right, and that’s one of the reasons why you chose that school?
-- well, yeah. I mean, you gotta think about it, in 1976, there weren’t SEM machines lying around grad programs.
I think they had actually a picture of the actual machine that you used.
Yeah. It was a very, very big machine.
In fact, you know, to have a scale for the audience, so you kind of get the scale, that’d be like me in 1976, and I grew a little bit more after that.
But this is like a four-story building. I mean, it’s massive! You can actually climb inside there, whole groups of people. No, no, I’m just kidding! But I want you to see the old machine. But that old machine cranked out an awful lot of – you know, we have these plates. I don’t know if the audience can see it, but we have these various plates that we could show portals of exit and all kinds of stuff. I’ll just show one really nice one. But anyway, maybe in the Show Notes, Lori might put a couple things in. But it was really good for me to learn, because then, Harvard had this idea that they weren’t producing clinicians in ’76. They were producing teachers.
So, their idea, when you went to Al Krakow’s program is, you’d be tomorrow’s post-grad Chairmans, researchers, and some would be clinicians, but that was – it was geared towards education. So we learned a lot about research, how to read research, how to read papers, how to discover the methodology, and were things done properly. And there’s just so many flaws in the literature, that that led Herb Schilder to even say that they should start a new journal. And it would be called The Journal of Retractions.
So, I’m – I’m hearing --
-- [laughs] I’m hearing from you that you – you did a year and a half of a literature review first. You – then, you had your idea approved, even. It had to be approved by, I think you said, someone named Paul Gron.
Yeah. He was at – at all of Harvard. We were at Harvard Foresight. So, Harvard Foresight is on the Fenway, and it’s a few miles away from the main campus, which is in Cambridge. But the Medical School, the Dental School, and all the big research and library, it’s on the Boston side. So, Paul Gron was a big, important guy, and we had to run our idea by him. And he had to help us set it up, because I didn’t know how to set up this project. And not only did I have to do a research project and do a literature review about all the things that have been done to date on what you want to do.
But then, there’s a second bibliography in here that talks just about how you do freeze fracturing and specimen preparation and – well, for the audience, you have to go through alcohol rinses and then acetone rinses and amyl nitrate rinses. And then, there’s all these preparations, sputter coating with palladium and gold, putting the specimens on studs. We – because we could take one tooth, and when we split it, we got three sections in the root. So, we decoronated it after we were all done, so we had coronal, middle, and apical third. And then, we split them on medial, distal, apex to crown, and got all these pieces that we could look at.
So, we learned a lot about it, and it just was a good experience for me. Although it was a lot of – a little bit of stress, because at the end, you walk into a room over in Cambridge, at the medical facilities over there that they have, too, and you have 12 people sitting at a big, oval table. And you walk in, and you sit at the head of the table, and for two hours, they can ask you anything they want to, about your research. And they’re not – not necessarily dentists.
Well, it sounds like you had a clear protocol and that you did a lot of documentation and were able to properly interpret the results. So, it worked out well. You are where you are today. But I – and I imagine there’s a lot of grad students right now, in the same boat. And some of them are going to do their thesis and then, maybe go into private practice and maybe even not research again. And then, there’s others who may continue to publish in research, because there’s definitely a need for it. I mean, we’re always testing, not only new techniques, but new technology needs to be validated as well, as effective.
And I think we had a similar type of thing, when we launched the EndoActivator. We sent hand pieces out to several universities internationally and asked them to develop a protocol and test the EndoActivator. So, why don’t you tell us a little bit more about that?
Oh, thanks. You know, when my partner, Bob Sharp, you know him well, when we did this, we did a lot of clinical cases. And we had a lot of empirical evidence that things were working. We didn’t have histology. So after we were very clear that it was working, as evidenced by looking in your mouth mirror and seeing chunks of pulp tissue coming up and debris. I mean, that was after we’d already done all of our normal irrigation. So we knew we were onto something good.
And so, we asked Pierre Machtou, Professor Machtou, he was at Paris 7, and he had residents, so he had Caron. Gregory Caron is a really cool guy. Gregory Caron actually was the lead project leader on the protocol. And what they wanted to do, again, is what is the shape, you know, because you can’t have people looking at the EndoActivator, and you take your foramens to 40, another school takes them to 15, some people are 2 percent, 4 percent, 6 – I mean, what is the protocol? So there’s a shaping protocol. And again, there’s an irrigation protocol, and I already said a lot of it, so I won’t repeat it.
But it’s not just temperature, concentration, frequency, volume, and all that. There’s a lot of things to discuss. So with the EndoActivator, Pierre got George Sirtes, from Geneva. He got Paul Lambrecht’s group, at the Catholic University of Leuven, in Belgium. He got Phil Lumley, in Birmingham. And I think he – yes, he got Kishor Gulabivala at the Eastman in London. And why we picked those guys is, those five guys in total, they had spent their life work on disinfection. That’s who they were. They knew protocols, they knew all the different things they had to abide by, to crank out good research.
So it took another two years, before we stumbled across – wasn’t stumbling, at all. It was painfully getting there. But we found out what the protocol was, and we can put it in the Show Notes. It’s exactly how to use the EndoActivator. In fact, if you use that protocol, every university around the world, to your point, will collaborate that they can get the same results. The people that didn’t follow the research, some of them were idiots [with emphasis], universities, they would take a clinical crown, and they would cut it off and then use the EndoActivator and stick the EndoActivator in the orifice. The EndoActivator tip would replace most of the reagent that was inside the shaped canal, and there was almost no reagent to agitate and exchange.
So if you follow the protocol, we need a pulp chamber, because we need a reservoir of irrigant. So, we had people that did – that did that. They decoronated the crowns. That’s crazy. We had other people that didn’t follow our irrigation protocol, because it was sodium hypochlorite EDTA to remove the smear layer. Once the smear layer’s off, you can improve penetration of sodium hypochlorite, by returning the sodium hypochlorite and having another agitation cycle. So some schools failed to use the protocol. They failed to use the reagent. Some didn’t use enough time. So they got – they didn’t get bad or dangerous results. They just didn’t get interesting results.
Yeah. I would think that it’s important to develop a very clear protocol, because when you launch a product, obviously, it comes with directions for use. So, developing a protocol, even before the product’s launch, will help you with the directions for use, I would think.
That’s exactly how it works.
And I know that you were not adamant that research could not be published if you did not get a favorable result. You were open to – they could publish, if they want. You just wanted the protocol followed, right? Because I know there’s some companies that --
-- don’t want research published, if it’s not favorable to their product.
You weren’t speaking of GentleWave, were you?
[laughs] It did [crosstalk] --
You know, I – this is really irritating to me. When we did this research, we flipped a coin. We hoped, but we knew, in our hearts, they would get good results, because we had already proven it, behind the scenes.
-- empirically. You had already seen it, clinically.
And to your point, they had to follow the protocol. So when we put our work out to get research – and incidentally, we have 19 peer-reviewed papers, from 19 different places, no school did two papers. So, that’s a big, broad collaboration, all saying that the EndoActivator has efficacy, and it was statistically better than a lot of the control groups it was tested against. So, my irritation is, we – the coin flip, for the audience, is you don’t know exactly if they’re going to follow all the protocols. You don’t know which kids are going to be assigned to do it. But you say, “Go ahead and publish.” So, we said, “Publish your results. Whatever it is, is what it is. I’ll live with it.” That’s probably why we have two or three or four bad papers.
However, many companies say, “If the – we get to see the results. And if we read the results, and we don’t like the results, the paper is deep sixed, and it doesn’t get published.” There’s a third category. Some universities and commercial companies work together, and along the way, if the researchers find a problem, it may just be something as simple as, “Do it 10 more minutes, 10 more seconds, 30 more seconds.” It might be, “Change your irrigation protocol a little bit.” Anyway, they’ll work together to get the best product. So, those are your three choices.
And a lot of companies strictly forbid research to be published, if it’s not favorable to their product. This is so stupid, because they don’t seem to understand if their product is ever going to be successful, many [with emphasis] people around the world are going to research that technology. And the truth will come out!
Okay. Now back to some things that can maybe go wrong when you’re researching. I’ve heard you, before, in a bit of a irritated mood, talking about some study, and I --
Doesn’t sound like me, at all!
-- heard you [laughs] --
-- I heard you say that “They’re just comparing apples and oranges. You cannot do this.” So, what did you mean by this, and can you give an example?
Well, okay. There’s a lot of people that do research like this. They’ll say -- okay. “Let’s take mesial roots of mandibular molars”, as an example. This has been done many times. “Let’s have at least 30 degrees of curvature of the MB and the ML, in that mesial root. And let’s take all the foramina to size 30.” Sounds innocent, doesn’t it? “And we’ll compare your files and Harry’s files and Jim’s files. We’ll compare all the files, and we’ll take it to length, to a size 30. We’ll transition the terminus to 30.” The problem is, you look at the methodology, and some companies don’t have all the tapers.
So they would test .04s, .06s, ProTaper doesn’t have a 30 in .06 or .07 or .08. It’s 30.09! So we can’t compare a 30.04 and a 30.06 and a 30.09! Please! Understand! This is loaded with problems, because these bigger tapered files weren’t made to go around big curvature. So number one, we’re not even thinking properly. Number two, we’re asking a file to do something it was never designed to do. And then, your research results are just apples and oranges, because those bigger tapers would cut more dentin, they’d cut a straighter pathway to length, they look like there’d be internal transportations, and maybe even external transportations.
So probably in this case, there’s just too many variables. You’re trying to compare different files, but each file, although it might have the same D0 diameter, has a different stiffness. So --
Different tapers. So they should at least freeze it and say, “We’re going to test all 30.04s or 30.06s.”
-- okay. Well, let’s talk a little bit now about confirmation bias, like meaning that you are only looking for evidence that supports what you already think, without keeping your mind open to possibilities. And we touched on this briefly, on – in our first season, when we talked about micro cracks. Because they were saying that the cracks were because of shaping. But that’s because they had in their mind, maybe initially, that the cracks were caused by shaping. So why don’t you talk a little bit about this? I think you actually touched on this, in your thesis, right?
We did, and you and I even did a show on this. So we’ll refer the readers to why crack propagation can be observed, if it’s even true. So fortunately, when I started reading all those studies, I was shocked at how silly some of the methodologies were. They never even understood, in one study, that the extraction itself can cause micro cracks of tooth structure. They fail to – then, we shape canals. So they were – a lot of people were coming from – maybe these files. Oh, maybe the bigger tapered files! Oh, maybe the reciprocation file! Maybe those are causing micro cracks. So they just didn’t freeze things.
And then, you can find other papers, there were no micro cracks. Here’s what I found. In my controls, there were no [with emphasis] micro cracks. That’s the ones we never – so, we had the virgin teeth. And then, we had the ones we just cleaned and shaped. So, we had another group that we just cleaned and shaped and fractured ‘em. That’s when I realized that sodium hypochlorite, over a reasonable period of time, can penetrate [with emphasis] 400 microns, back into the dentinal tubules. So, we learned an awful lot. And of course, freeze fracturing, mechanical fracturing, there’s a lot of ways we can introduce artifacts into our observations.
Okay. So maybe avoid making assumptions, and really look at everything so -- all of the evidence, so that you can make a logical conclusion, without assumptions.
I mean, isn’t it interesting to you, a layman, that if I was going to look at micro cracks, and I’m trying to – let’s look at it from a commercial context. So I’m trying to sell a file over here. And my file is really like a 20, and as one of the people said, recently, one of the professed scholars of our world, “It has almost a zero taper behind the apical one-third taper. Our instruments are the perfect instruments, for the perfect result.” This is dripping with arrogance, because they’re not thinking – that they’re comparing it to a nine percent-tapered instrument, a six percent, a seven percent.
You gotta compare apples and apples, because we do have canals that are big. People, we do see patients, every single day, these guys, younger patients, power roofs, upper molars, the foramen’s 30 or 40! So please, take your little, tiny files, and throw ‘em in the wastebasket! They’re junk, in those cases! So we love minimally invasive. We love protecting tooth structure. But, you know, you have to have the right, appropriate shape, for the right tooth.
Okay. Just let me go back to confirmation bias, just for a second, because I think another good example of that, we talked about on a previous show, just a few shows ago, when you talked about how your case was misrepresented by Dr. Ove Peters. And it was – there was something like, “He assumed [with great emphasis] that” – now, what – how did it go? Can you remind me, basically?
Well, you know, Ove’s difficulty that he’s experiencing – and it shows. He doesn’t seem to notice it yet, but he’s been an academician for most of his professional life, and he’s dabbled at clinical endodontics. And when you’re a professor, and you’re doing all the research that Ove does, with all of the groups around the world, are you thinking he’s practicing like half a day a week, another half a day a week? Doesn’t matter how many days. He’s not a full-time practitioner. So for him to look at a case done 40 years ago and judge the shape and – of that era, with a current era, with a new file he’s launched with Dr. Bruder, it’s – it’s ingenuous. Okay? And then to say he would have grave concerns restoring that case, well, we showed a 25-year recall.
So a professional just simply calls Cliff. “Hey, I’m going to show one of your cases. Do you have a recall? I was curious! It looked like you over-shaped!” I don’t think he did – I did over-shape. But if you’re comparing it to TruShape, where he wants to see a pencil line, going through the canal length, you know, one thing that’s funny. I’m going to make – bring this up. I probably shouldn’t. I’m going to get in big trouble! These guys that are on this – like the true anatomy bandwagon, and they’re talking about how important is -- these little conservative shapes are, because it’s restorative driven. I’ve been in study clubs my whole life, called “Interdisciplinary Dentistry”! The American Academy of Aesthetic Dentistry is one of those groups.
They have all the disciplines come together, once a year, and they have an annual meeting. And we hear all about the restorative side, the implant side, the sinus lifts, the maxillofacial surgeon. We always had an eye towards the [laughs] – the restoration of the endodontically treated tooth! And some of these people, to commercially sell a file, now they have a newfound sense of, “We’re going to save teeth, because we’re looking ahead, to restorative.” You always should be looking ahead to the next and the next steps that will follow.
So maybe more of a literature review and not having assumptions [laughs]?
Well, I think our passion for a lot of things – I’ll just say it bluntly. Teachers today better start teaching endodontics again. You know, we’re not teaching files. Files come and go. They’re like underwear. I don’t know if I can draw underwear. Well, I won’t try it. But underwear is changed daily, I hope! And files come and go, just like dirty laundry. And so, really, the gift of the teacher is not to be touting so significantly his or her files. It’s really to be talking about how to do clinical endodontics, because we’re all going to use a file, at some point.
Okay. So, back to research.
I – I’m definitely getting the idea that not all research is equal and that it needs to be thought out and approached with an open mind. We look forward, in the future, to having some grad students on our show, to talk about their thesis and explain their process. I think that’d be really interesting. So, thank you for all of this information you gave us.
Yeah. I have a lot of papers in my mind, and it’s hard not to blurt one more comment. But I think I --
-- should probably bag it.
Well, did you – I think you had a quote. Did you want to – an Einstein quote? Did you want to say that?
Well, I was thinking about the famous article that everybody quotes. It wasn’t the Einstein quote.
But it was like, “Files, rotary shaping files, only touch 60 percent [with emphasis] of the internal walls!” Same guy, few years later, made a file that went from a 25.08, and now, the pride is, it’s very, very small. It snakes through these canals. And you know what? Go ahead and do the research, big guy. You’ll find out it probably touches 20 percent of the internal walls! And how is he irrigating? Oh, he showed a little cannula that has bifid drops coming out of it. You know, these guys need to figure it out – these guys that go from academics to clinical, because they need to understand the clinician’s perspective, before they have such strong opinions about their hollow research.
Okay. So, again, back to an open mind.
Open mind, and yeah. I think Einstein said it all. “We wouldn’t’ – what [laughs] – “If we knew what we were doing, we wouldn’t call it research!”
Something like that.
SEGMENT 2: ProTaper Q&A
Okay. All right. Well, thank you. So, we have another Q&A segment for you today. And these questions are from Chinese clinicians, and they’re related to the recent launch of ProTaper Gold in their country. Now, obviously, these questions are relevant for everyone, because ProTaper Gold is used around the world. So that’s kind of what the theme of these questions is going to be.
And it’s the tail end of a little assignment. Several months ago, in preparation for the launch in China, I did a little bit of educational promo, to get people excited about the pending launch. And then, they got to see a one-hour Ruddle webinar on ProTaper Gold, and that was to get ‘em completely baptized. And then, they launched it! And they launched it in several cities in China, and thousands of people took those classes. And these are some of those questions, because the third part was, “When you’re all done, and the dust has settled, come back and ask me some of your initial questions.”
Okay. So let’s get on, then, with the questions.
Maybe say the disclaimer.
Okay. Well, I am going to be reading these questions exactly as they’re written. And keep in mind that English is not their first language. So, if I sound a little odd, that’s why, because I’m just reading exactly as they’re written.
But do you agree, it’s better to do it this way, than me trying to give the answers in Cantonese or Mandarin? [laughs]
[laughs] Well, I think – unfortunately, even if I read it, and it sounds a little awkward, I know that you’ll understand it, because it’s a pretty – dentistry’s a pretty international language.
So, okay. So, here I go. Here’s question number one. “Compared with WaveOne Gold, the shape of canal prepared with ProTaper Gold is larger. Whether it means ProTaper Gold cut too much?”
Okay. What I’ll do is repeat it a little bit. But what I’m hearing is that, if they’re comparing the WaveOne Gold with the ProTaper Gold, they’re wondering if ProTaper Gold cuts a bigger shape.
WaveOne Gold has a – let’s do it over here. We have a 20.07, small. Then we have a 25.07, that’s called primary. Then we have a 35.06, and we call that medium. And then we have a large, and that would be called a 45, and that would be .05. So now, if you look at ProTaper Gold, we have an F1, and that is a 20.07. And we have an F2, and this is a 25.08. And we have an F3, and that’s a 30.09. And blah, blah, blah. There’s some other finishers. The point is, I’m not sure which the colleague – which – what’s the comparison?
If you’re comparing primary, which is the most frequently file carried to length, compared to the F2, yes, we have a – 1 percent more taper. I don’t think it cuts a bigger prep. If you’d compare F1 and F1, okay. But the thing we’re not talking about is how the colleague uses the file. If the colleague is just peck, peck, peck, peck, all the way down to length, that’s one kind of a shape. That’ll be closer to the silhouette of the file itself. If the colleague is brushing a little bit, into fins and eccentricities, the shape will get a little bit bigger, but not so much because of the taper of the file, just because of the method of use.
So, to me, it depends on which file the colleague is actually comparing, to have apples to apples. This isn’t quite apples and apples, but it’s quite close. Of course, over here, if you’re comparing medium with the F3, you’re starting to see a lot of difference in taper.
I’m actually almost wondering, because the way he says, “If ProTaper Gold cut too much”, maybe he’s thinking in terms of minimally invasive endodontics. And perhaps maybe he’s implying that WaveOne Gold might be safer, because it cuts a smaller shape? I don’t know.
That could be true. If we go back over about 40 or 50 years of research, I guess we can say this briefly. There was the Wallace review paper, and then there was the Baumgardner paper – Baumgardner. This one in the review papers showed that most dentists over 40 years of dentistry, this is kinda the average. They want a 40 file, at length, at the terminus, with about a 6-percent taper. Baumgardner said, “But wait a minute. You can have 100 percent smaller terminus” -- 20 to 40, 20 over 20, that’s a 100 percent. “You can have a 100 percent smaller, if you increase your taper!”
So, somewhere, though, the edges of the truth show up. Somewhere between a 40 and a 20, and the different tapers, that’s kind of the aspirations to get reagents effectively in the apical third and around curves, so the reagents can be activated, agitated, and moved into the uninstrumentable portions of the root canal. So if you have GentleWave, if you have laser endodontics, you can start talking about, you know, a 20.02, maybe? You can have a lot more tooth structure, perhaps, but you’re going to have to use a different technology, because there’ll be no way to clean this, in traditional methods, and there’ll be no way to fill it.
Okay. Let’s go on to the next question. “How about the comparison of ProTaper Gold versus other NiTi files on the prebend ability?”
Well, again, we have to talk about apples and apples. Most instruments today are heat treated. That means they go through some kind of heating and cooling cycle, and that changes us from our martensitic to our austenitic. We go through these phased transitions. So, all heat-treated files can be precurved. Some can be precurved, easier. If you say the file is like four-percent taper, you can easily – you can – it’s called the orthodontic bird-beak’s plier.
It’s used in ortho, but we used it for decades in endo, to precurve files. So it has a tapered beam --
-- it has a tapered beam. And then, there’s another arm, up here. You put the file – this is a plier. You put the file in the beam, take the handle, and pull the handle through a radius, and you can land a perfect curve. As you go up, you’re going to get a much more gentle curve. If you get right down to the end of this, you can start to curve your files to make them look just like that.
So, all files can be precurved, specially heat treated. Based on the taper, some smaller tapers will hold their prebending a little bit better. Some of the big ones, like when I bend a 30.09, I can bend it just like that, but it’s easier for that bend to start to relax because of shape memory and straighten out a little bit.
Okay. Next question. “Could you explain the difference of brush follow and follow brush?”
Sure. So let’s just take an iconic tooth. Let’s just take our molar, and we’ll even put a little concavity in here. And let’s just say that our canal’s coming down, like this, and it’s coming down, like this. And – you know, okay. We’ll do a little bit more, and we got a pulp chamber. Okay. This is the furcation. So when we’re working – let’s remember another era. Coronal, middle, and apical thirds, we have a lot of canals that are not round. There are canals that have irregularities. There’s canals that have fins, okay? So, we brush!
So, when you’re working the files down, the shapers, the ProTaper Gold shapers, when you’re running a shaper down here, you want to brush away from furcal danger. If we do a cross section through the root, our canals are closer to the furcal side concavity. So we brush [with emphasis] away from furcal danger, to intentionally move the canal coronally, away from this area, right in here, this furcation area. This area, right in here, that’s the danger zone. So shapers, we brush to relocate the canal away from furcal danger.
When we – we have research that has shown, when we’re finished shaping, we have more – we have more residual dentin on the furcal side. When you just drop a file into a canal that’s already closer to the furcal side concavity, you’re going to have the first instrument, the second instrument, you’ll get shaping waves, where – like dropping a rock in a pond, you get emanating, concentric circles. So, the shapes drift! The shapes drift towards furcal danger, and it thins the root and sometimes overtly strips the root.
So, brushing with the shapers is intentional, whereas in – when you get into the apical thirds of roots, and you just look at cross sections, roots are more irregular. Canals are more irregular. They’re rounder. So, you just let the finishers – okay. That’s the shapers. You let the finishers run – say, “run”! Let them run in. If they bog down a little bit, pull it up a little bit. Then, let it run! Bogs down, pull it up. So we’re following and brushing, versus brushing and following.
Okay. “How about the difference of ProTaper Gold and ProTaper Next from the usage and case-selection point of view?”
Very, very different instruments. I’ll just say this. The worst thing that ever happened ia when ProTaper was branded ProTaper Next, because ProTaper Universal and ProTaper Gold, which have nothing to do with ProTaper Next, is still the number-one-selling file in the world. So, when you add ProTaper Next, a lot of colleagues were deceived in the marketplace and thought that meant, “Oh, this is the next big thing.” It’s a completely different file. Here’s the differences. They have different tip diameters. They have different tapers, different geometries. They have different metallurgy. They have different rotational cross sections.
ProTaper Gold is a centered mass of rotation, whereas we’ll have an offset mass of rotation, to get a bigger envelope of motion. The back end of ProTaper Gold, the finishers, is about 0.10 millimeters. The back end of ProTaper Next, and you look at the X2, the X3, and those, is about 0. – I’m sorry. Whoa, geez! I’m going to lose it all now. The back end is about 1.2 millimeters, versus about 1.0. So this is PTN, and this is PTG. So there’s quite a bit of difference, here. And so, that’s the differences. And then, the – one of the problems is, the X1, the first instrument, ProTaper Next, is a 17.04. The X2 is a stunning 25.06, and the X3 is a 30, and it would be an .07.
Let’s not talk about the rest of them. There’s an – up to an X4 and an X5. If you look right here, this is the biggest jump in terminal file diameters in the business! If you take 17 to 25, I think it’s 8/17ths. It’s 8/17ths. That is 0.47. That means this tip is 47 percent bigger than the 17! That’s why there’s so many broken instruments. It’s the biggest jump in the business! So, it’s not my file design. The envelope is interesting, because it means there’s less engagement between file and dentin. But on the other hand, when you have those big envelopes, you cut full shapes. Go look at the x-rays! Just look at thousands of x-rays of PTN, and they get pretty big. Those shapes get big.
Now, he says, as far as case selection goes, would you ever choose ProTaper Next? You, personally?
I don’t use ProTaper Next.
And – and you know, I think we want to – I want to dismiss something. Because I hear teachers say this, “I, thoughtfully, Lisa – I thoughtfully look at my x-rays, and I note the different views.” And then, I go, “Let’s see. I have nine systems in my office.”
“Let’s see. Eenie, meenie, miney, mo. Catch the file by its toe!”’ No! Get good at something! You know, do you see professional athletes using different weight soccer balls? Do you see footballs on Sunday football, are – some weeks, are the balls a little longer, a little bigger?
Maybe pumped a little fuller? [laughs]
Yeah. When I play baseball, and I bat, you know, my bat’s always 32 inches, and it’s so many ounces. But you know, that guys’ pitching tonight. So, he’s a different pitcher, so I’m going to use a – no! Nobody does this, except people trying to sell files!
So, you don’t use a system of analytics to determine [laughs] which file to use?
Yes! No. So get really good at something. And do it over and over and over. That’s what the pros do. And then you’ll know the deficiencies of the instruments you’re using. You’ll know their strengths. You’ll be perfect. When you’re using different instruments, and especially people that hybridize – don’t let me get started.
Okay. Next question.
Oh, yeah. Get it up.
“What are the recommended range of speed and toque? Why? Can we adjust the setting?”
Yep! So, for ProTaper Universal – for ProTaper original, this is going along in a timeline. And then we’ve evolved over to ProTaper Gold. The speed has always been 300 rpms, and the torque has always been 5 to 5.2 Newton centimeters. The most common mistake around the world is the company that sells them! Because they erroneously have you using different torques for your SX, S1, your S2, your F1, and your F2, and your F3. No! It’s one speed, and one torque, for all ProTaper. Why? Because that’s how they were validated! We did it with the engineers, thousands of cases. And forget us and the human touch. They put them in machines, and they rotate these things, and they can look at bending moments. They can look at elastic – cyclic fatigue. They can look at unraveling, everything. Okay?
So it’s validated scientifically. And then the company has suggested different torques, every two instruments! Elio Berutti, my pal in Italy, has written papers on this, and he has shown an enormous [with emphasis] – I think it was 10 times more breakage, if you change the torque from file to file. So they’re meant to run at one speed and one torque. The second part of the question was, obviously, if you’re a learned clinician, and you have some experience, and you’ve been using ProTaper for a while, some people might say, “Well, you know, I run mine at 400.” I’m not going to lose sleep over that. But don’t drift too far away from excellence.
Now, 5 to 5.2, a lot of motors that dentists have around the world only go to 4! So, the company will even recommend 4 to 5.2 Newton centimeters, because they recognize, not all colleagues will buy a brand-new motor! So, as you go down in torque – as you go down in torque, your instruments will not behave as well. Remember, ProTaper has progressively increasing tapers, on the shapers, and progressively decreasing [with emphasis] tapers, on the finishers. That means the shapers do most of the work. You need a big torque to move those big blades, and that’s the blades away from length.
Now when you get down to seven, eight, and nine percent taper on the finishers, again, you need a big torque. That’s a big piece of metal! So you can change them a – as you get more comfortable.
But you – if you reduce the speed, you wouldn’t, for example, raise the torque. Or if you raise the speed, reduce the torque, or something like that?
You know, if somebody’s doing that, they should just invent files.
[laughs] Okay. [laughs]
They should have their own truth and discovery. If the question is, how to work the safest and the most efficient, you know, you can turn the speed up to 6- or 700 rpms. A lot of companies do that, because their instruments are really inefficient. We say they’re – they’re really dumb instruments! So, by turning up the speed, you could overcome deficiencies in design. If you lower the torque, you might never break a file, but you never may finish your shape. [laughs]
[laughs] Okay. Moving on. “Can you explain more details and laboratory data on gold heat treatment and the impact to the performance of NiTi files?”
Well, gold heat treatment is like blue wire heat treatment, M wire heat treatment. These are all proprietary. I don’t know the exact temperatures. But we do know that heat treatment massively [with emphasis] – massively – or I’m sorry, increases the resistance to cyclic fatigue. So, heat treatment’s a good thing. This is a file. We’re going around a curve. On the inside of the curve, you have compressive stresses. On the outside of the curve, you have tensile stresses. So, it’s like taking a paper clip, when you’re going around a curve, and you’re spinning 300 rpms, and you do this with a paper clip, until it breaks.
Thank you for that information.
Yeah. And listen. I’m coming back to China. So, you know, right now, we’re separated by a little distance, but we’re still connected! So I hope you’re having fun over there, and get it done!
CLOSE: Superlatives – Best & Worst of 2020
Okay. So now that 2020 is coming to an end, we thought it was a good idea to close our last show of the year with a Superlative segment. We’re going to talk about – I’m going to ask my dad questions. He’s going to give us the best and worst of 2020. So here we go! Most influential clinician of 2020?
Well, I’ll see Rella and Gordon Christensen, for all the COVID work they did, in their – what was it called, “(Clinicians Report)”, the little booklet that comes out?
They had some really great information Rella put in there. But actually, if – if we’re going to give two awards, I’d like it – to give it to all those practitioners who served the general public, when COVID first hit. I think they’re heroes.
Yes, great. Favorite Ruddle Show segment this year?
Well, they’re all interesting. I guess probably I had a lot of fun with AI, because artificial intelligence was something I was very interested in. And Isaac and I talk about it, quite a bit. And – but I had to drill down and go a lot deeper. So, that was fun.
I think --
Well, maybe Andreasen’s tribute was fun.
Yeah. Because you know, he meant something to me back when I met him as a kid, in Boston. And he was this great guy. And so, yeah. It was not fun that he died, but it was a fun segment to do in his honor.
Okay. Most challenging Ruddle Show segment this year?
[laughs] Well, I’m not the computer guy around here, but everybody but me is. And that means there’s five people that produce this, okay, five people. But I heard that we lost our first four shows in Season 1. And we were – we took the hard drive down to a very competent computer store. They had it for a few days. The news initially was, “Yeah. We think it’ll be no problem.” Then, it was like, “Well, there’s not much here.” And finally, what they could say was like a couple shoestrings and maybe a roll of toilet paper. So, it – in other words, nothing!
And so then, we brought it home, and Isaac was able to discover how to save everything.
Yeah. That was – I do remember that. [laughs] That was quite trying. Okay.
A lot of lost hours, right? [laughs]
Yes. I can add one more thing. And we did shoot a – an opener on COVID, right before the shutdown. And we ended up going back and losing that segment and redoing something different [laughs].
Oh, because of, things were changing so fast on the ground.
It – very rapidly changing, and it – our opener became very irrelevant.
Okay [laughs]. Favorite Ruddle Show opener of 2020?
The favorite opener. The favorite opener?
Yeah. Like --
Well, maybe sports. We did some sports.
-- some sports ones.
I liked that. I think the hiking was fun, for me. Outdoor stuff, yeah.
Your least favorite Ruddle Show opener?
Oh, my interview [laughs].
That was really not necessary.
Oh, yeah. Okay. When we did the interview, that was a hard segment for you, because --
Yeah. Because you’re talking about your life and your journey, and everybody goes, at some point, ‘Yeah. Who cares?’ “
Okay. Best virtual dental meeting of 2020.
IFEA! The International Federation of Endodontic Associates, out of Chennai, with the – in collaboration with the Indian Dental Endodontic Society, did just a magnificent show.
Okay. Most talked about technology of 2020?
Well, I thought it might be GentleWave. And to me, that was a fabulous thing, because for – apparently, I fell far short in my career, because for 48 years, I’ve been talking about 3D disinfection, and I think GentleWave helped a lot of people go, “Oh! Maybe if I spent enough money, I can do it, too!” The thing is, we could teach disinfection with a 25-cent syringe. So it was good, because it brought a lot of illumination to what we need to be doing.
Okay. Most overlooked technology of 2020?
Oh, the EndoActivator!
I mean, we have 90,000 users. GentleWave has 700, 800 users, okay. So that’s not even the point. The price difference is so much. But I think if the company -- Dentsply Sirona, they rarely market it. They rarely talk about it, but we have 19 peer-reviewed papers. We have 90,000 customers. It’s being taught in most dental schools, but most dentists, when you talk about it, they go, “What’s that?” So, that means to me, there’s still a lot of growth possible and help people get better jobs with their disinfection and success.
Okay. Best question you received this year?
I don’t know if it was this year, but the best question I ever received was from Edmond Koyess. He’s a guy from Beirut, Lebanon, and he asked me a question in Jordan, many years ago. “When does endodontics truly begin?” That’s a mind bender.
Think about that.
Okay. Best thing to happen to dentistry in 2020?
The best thing to happen to dentistry. Oh, we opened up dentistry for the general public to come in, again.
[laughs] After – and then, worst thing to happen to dentistry in 2020?
When we had to close down the dental offices because of COVID.
And when I say, “close down”, there were the frontline endos, primarily, that kept the show going. But most people were at home, most dentists.
Right. Okay. Now, this is a personal question. Best personal moment of 2020?
The best personal moment. I think starting this show.
That was kinda like a – a dream of mine, that I had for many, many years, actually. And I was mapping out the last – they say, “the back nine of your life”. And I was thinking, “Wow, we could reach out and touch a lot of people.” And today, this year, we did it. We started it.
Maybe just learning how to use Zoom was something that really was great for you, this year.
Yeah. It helped – it helped us in our interviews. I mean originally, we were going to have people fly in. I was going to fly ‘em in, they were going to stay in a hotel, they’d sit right over there, in the other – the third set, and we’d do these real personal interviews. I’d have dinners, catch up with all my old pals and all that. And then COVID hit, and then, Zoom was really an important part of communicating.
Okay. So, now, the last question I’m going to ask, because we’re out of time, is the greatest loss of 2020?
Where’s my whiteboard? Well, anyway --
-- it’s number 24, also known as number 8, and that’d be Kobe Bryant.
Yeah. It’s hard to believe that was this year. It’s – so much has happened [laughs].
So much has happened, but I’ll never forget that Sunday morning.
It’s – you know what? That happened pretty early on in the year, and every – like all year long, every time something has happened this year, I’m like, “I guess Kobe didn’t have to look at that or see that.” [laughs] You know? So, that’s a wrap on Season 3.
Will there be Season 4?
Well, you know, there’s five people that comprise this team, this multimedia team. And on a very close – very narrow vote, three to two --
-- we voted to go ahead. We voted to go ahead and make it till next year. Go ahead.
[laughs] Okay. So, everyone have a great holiday, and we will see you next year, in February.
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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.