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.

Welcome to “The Ruddle Show”. I’m Lisette, and this is my dad, Cliff Ruddle. Today, we are back in the studio, filming another episode of The Ruddle Show. It’s our first show back, because like most of you at some point over the last couple months, we were under a stay-at-home order, to stop the spread of COVID-19. So, how – did – did you like staying at home? Was it – did you find it fun? Did you do different kinds of things?

There were three things that probably you could make the lemonade out of the lemon. Zoom was one of them. First, we discovered Zoom, because that was our way of working. And then, that Zoom thing rapidly carried over to a lot of places around the country that wanted a Zoom session for their colleagues, because meetings were canceled. So I did probably six or seven or those. Last night was kind of interesting, because I did the graduating class of the University of the Pacific in San Francisco, my alma mater. So, that was kinda fun. And the side story on that was, they wanted me to come and – well, they called it “Endotainment” --

[laughs]

-- and so, they asked Ruddle, because he’s a clown.

But anyway, they had – the hope was to pick up their spirits, because here’s the story, real quickly. Their last days at the school, I understand, were very, very early March. And that means that the graduating class, that last quarter, they’re doing a lot of their final bridgework, they’re doing restorations, operative. It’s their last chance to really tune up, gets their heads right, and then, go out and become the professionals they want to be. So, these kids got stalled four times. They were told two weeks, and then, they got two weeks further into it, and it was another two weeks, and so on, and so forth. So, they’re a little insecure.

So we had a good session, last night, and it was interesting, hearing the kids’ questions and – they’re so sincere. They wanna really do good, and they’re a little worried that they’re not quite prepared. So I had to give ‘em several little stories about they’re gonna be good, they’re gonna be as good as they decide, and the future’s very bright for them, even with this COVID. So, Zoom came into our lives. That’s allowed us to do lots of things, now, overseas. I really like the – I discovered sports. I was a little bit athletic, growing up, and I love – love sports.

So, we have this little park down the street and there’s a basketball hoop. And so, I got out the old Spalding NBA ball, and I was playing by myself, and I was playing with my grandkids and started to realize that I need a little more oxygen.

[laughs]

But that’s okay. I’ll discover it, I think, if I keep playing. There was a lot of ferocious ping-pong matches and cornhole. For the international guests, it’s a 16-ounce bag, filled with kernels of corn. You throw it 27 feet, into an inclined plane. There’s a little hole, and you try to throw that bag into the hole or slide it up the ramp, into the hole. All this is good stuff, and it was something I was not doing before COVID. I wasn’t doing the basketball. There was no ping-pong. I was walking and stuff and doing other things outdoors, but this was fun.

And maybe one last thing was, it was a chance to really reach out to people and maybe be more authentic. You know, we always talk to colleagues – I’m talking to people every day, multiple people around the world, literally. But now, we could maybe have more time with not a schedule. Maybe that’s the word, “schedule”. There wasn’t that, you know, dentists know schedule. 8:00, the 8:15, the 9:45. Anyway, I can call up a guy like Manor Haas, and I mean, this guy went through COVID, so he told his story in a very compelling way. But I wanted to follow up with him. We were on Zoom together, one-on-one, just talking, for probably almost an hour and a half.

So, it allowed me to be more personal with some people. Some people got sick. Couple people died. So, we could be a little bit more authentic in our lives. How about you?

Well, I’m a big work-out person. So, I – we got the whole family working out together, daily. Like, at first – like, it’s hard, when you – we have our schedule. And then, all of a sudden, we’re thrown into a different situation, and --

Mm-hmm.

-- you know, I’m a very schedule, like, regimen person. So, like I – I kinda needed to get everything going again, in a way that I was comfortable with. But one thing we started doing, every day at 1:00, is working out together as a family.

Nice.

And that was fun, and we also did this dance thing, too. So that was fun, because --

That’s all four of you, right?

-- yeah. And I’m not really a dancer, but I feel like it’s helped me – [laughs] like, just my dancing skills have helped me, like in karate and stuff. So --

You know, Jim Rice, famous wide receiver for --

Or Jerry Rice.

-- Jerry Rice --

Yes.

-- from the San Francisco ‘49ers, he took ballet.

Yeah. I remember hearing about that. So, yeah. It’s a great cross-training thing, dancing is. My daughter, Eva, she is – she’s a – I guess she’s 19. She used to go out, every single night, and we’d hardly see her. Not – she wouldn’t have dinner with us, ever, and – she actually happily stayed home for a couple months with us, and I got to know her, again. And we’re friends, and --

[laughs] Bring on the virus, huh?

-- yeah. We did some hair coloring. She did a lot of painting. We did some house projects together. So, she’s now just starting to disappear again, like, out with her friends. But I – it was really nice, having her around.

I have a question for you. Did Isaac, the guy that’s producing this show, I call him affectionately, “The Shooter”, did he ever even come out of his room?

You know what?

And maybe describe his room to the colleagues.

Okay. Well, first of all, he is not the kind of people that really likes to go out a whole bunch. You know, he has – he has this huge, like, set-up that he – of computers and stuff at home, that he does all his --

Could we just call it the inside cockpit of the space shuttle?

[laughs]

I’ll tell you, he discovered a lot of things that he shared with me. It was pretty thrilling stuff, technical stuff.

-- yeah. No, he’s – he’s been thriving during this time.

So, what do you got for us today?

Well, I think you’re gonna talk about 3D disinfection with ultrasonics. And then, we’re gonna do a “Fresh Perspective” segment, to get you to think a little differently about MIE. But before we get started with that, if you could just say really quickly one thing you did not like about staying at home, what you say it was?

I felt I lost some freedom.

Okay. And for me, I can just say really quickly and easily, not having sports on TV was painful [laughs]. So --

[laughs] Yeah. Maybe the biggest pain of all. Yep.

-- [laughs] so, I mean now, I – a lot of times – I guess a couple times I thought, “Oh, basketball’s on. What?” At least, showing an old game, but Isaac recognized right away, when he walked out, that it was actually E-sports. Like, it wasn’t even a real game. So, that’s what we’re seeing on TV now [laughs].

I guess we can’t let this slide, but we never talked about, did we watching movies or stuff, but we did watch “The Last Dance”.

Yes.

And for our international colleagues, that was pretty much the story of Michael Jordan’s career, from the late ‘80s through the ‘90s, and he won three in a row, was out in basketball for a couple years, then won three in a row. So, it was a fascinating story about success and all the elements that are designed into success.

Definitely a must-watch, even if you don’t like basketball. It’s still, like, very – very good show.

Yeah.

All right. Well, we have a lot to cover today, and we’re excited about it. So, let’s get started.

I’m very enthusiastic to talk to you today about 3D disinfection. You know, for a lot of dentists, and I mean this kindly, this is something that they’re really learning a lot about in the last decade. But fortunately, I went to a program where the emphasis was on treating all the root canal system. So, we always spoke affectionately about the thrill of the fill. Well, you can’t fill into spaces that are blocked or occluded by tissue. And we have to remember Newton’s Laws of Physics. Only one mass can occupy the same space at the same time. So, if we’re going to fill three-dimensionally, we need to remove all the contents from the root canal space.

So, today, we’re gonna emphasize ultrasonics versus sonics. We’ll compare and contrast and then, look at – a little bit about how they both work. A few words, ultrasonic has been used in dentistry since probably the ‘50s or ‘60s. Howard Martin talked about it as a way of doing some cleaning and shaping, where they would use the sonic – the ultrasonic action and energy to shape canals. It never really caught on. And although you could find a few users, here and there, the vast majority of dentists never, ever used ultrasonics for cleaning and shaping canals. And let’s look at why.

First of all, this is our assignment. And as you see, this rotating actual root canal system, on a retrieved tooth. The crown’s been beautified, but you can see they’re complex. And after we make our access, after we do glide path management, and after we arrive at the shape that we feel is appropriate for the root that holds it, then we must realize that there’s a lot of tissue left in the branches. So the trunk of the tree is where the files are going, but the limbs of the tree oftentimes hold pulp tissue, necrotic tissue, microbes, things like that. So that’s our assignment. This is all left, after perfect shaping!

So if we look at 3D disinfection, and we’re looking at the apical view of the tooth, let’s go up as the file leaves the root, to see what’s going on. And you can see all the pulp tissue left on the walls. This is after a nice shape. You can see anastomosing between systems. So in a lower molar, MBs and MLs frequently have anastomoses between systems. As the file goes around the curve, you can see it’s loaded with debris. And a lot of dentists are thinking, “I just got my shape. Let’s fit the point, and let’s pack!” Okay?

But let’s understand, we still have things to do. And the things we have to think about are removing all the pulp. And I always like to say this, but why is this extraction, why is the extraction so successful? Because it serves to remove the pulp, 100 percent of the time. So endodontics must parallel the extraction, where we leave the root behind in the crown, but we take out all the system. That’s debridement. The smear layer is simply a byproduct of our instruments. So as our instruments spin or reciprocate or cut, anything that cuts, below the orifice, is leaving a byproduct, and that byproduct is called the smear layer.

And the smear layer should be removed, because the smear layer is not just dentin. The smear layer’s actually a cocktail. It could be pulpal tissue, dentinal mud. If present, microbes. So, we need to get the smear layer out. The smear layer opens up the dentinal tubules, so we can get penetration and circulation and digestion in the uninstrumentable portion of the root canal space. Finally, microbes – bacteria are pretty sophisticated. I’ll be very simple today, but if you talk to people twice as smart as me, the virologists, the microbiologists, we have an enormous population below the orifice, or can.

And oftentimes we don’t realize that these bacteria colonies, they produce sticky polysaccharides, and that’s like the moat around the castle. So sometimes our Clorox and our different methods for disinfection don’t get into the castle, because of the polysaccharide. So, the populations of bacteria need substrate to live, and when they get too big for substrate availability, they talk to each other through quark communication. Quark communication. And they’ll split, and one population’ll swim downstream, set up shop and residency somewhere in a distant tubule, or in the body of a canal, or in a lateral canal. Use your imagination. So, we wanna get these things out. That is disinfection.

Well, you know what? The father of dentistry was a French guy. You remember his name? Pierre Fauchard. And what’d he say? He had all those objectives after mechanical crown preparation. One of ‘em was, “Flush the toilet of the cavity.” Oh, I love that! Got shivers down my back! “Flush [with emphasis] the toilet of the cavity.” Well, if you go forward about 100-and-some years, you get to Herb Schilder. He was probably the most recognizable name in endodontics, internationally. Schilder talked about “Flush the root canal system.” Okay. So, I think it’s time to have an honorary flush, so that we all grab the thought and hold it forever in our minds. It’s important to do a lot of rinsing, flushing, irrigation, activation! That’s [with emphasis] how we clean root canal systems. [Sound of toilet flushing] Oh, that sound at the end! It’s fabulous!

Okay. So, if we look at Frank Paque, and we look at some micro CTs, you can begin to see on patients of record, these are extracted teeth that he scanned, look at all the anatomy! Look at the anastomosing in between the MB and the – the MB1 and -2. And then you can see the origination and the anastomoses of another whole branch. This has had a palatal root resection, periodontally. So I’m treating the buccal systems, and notice the MB, quite similar. My anastomosing’s a little more coronal, but off the origination of that anastomosing, we see another whole system, with its own separate apical portal of exit. Ruddle didn’t even know it was there!

So, the expression reminds me, “Even the monkey can fall out of the tree.” So the point is you need to have methods that give you forgiveness, so you can be more than you are and closer towards all you can be. And you can see another beautiful Frank. Look at the divergence, deep in the body of the root. Here, we’re working through the anterior abutment of a four-unit bridge. In the most funereal sense, this abutment’s strategic, and you can see the deep – in the canal, there’s a trifurcation, three systems, merging and bifurcating apically. 3D disinfection keeps coming to mind. 3D – how do we get the anastomosing? How do we get the mid-mesial-apical? So, mid-mesial here. Now we have a mid-mesial, really deep, lateral canals everywhere.

You know, when you start to do endodontics like this, it really makes you think about Hess’ work, “Root Canal System Anatomy: Success and Failure”. And when you’re hanging those bridges and splints on those endodontically-treated teeth, you want abutments that are predictably successful! Okay. So, we’ll look at maybe one more. I think that’s it. Yeah. Here’s the one more. So, my multimedia team has made now 15 collages, 3 across, 3 down, we got 9 images. But just look at anatomy. Just – everywhere you look, you see anatomy. Anatomy, anatomical variations.

A lot of these teeth that fail, begin to think about root canal systems. Most dentists are thinking they go into a molar, mandibular, three canals. Look for the fourth. And then realize there’s multiple portals of exit off those canals. So, what do we do? What are the methods? What are the tools in the toolbox that we can use to do 3D disinfection? I’m not gonna talk about lasers today, and I’m not gonna talk about GentleWave. Those will be handled in other topics, and if they’ve been handled already, in earlier, seasonal work, we will revisit them, because the news is always changing.

But basically, you have your chemicals. And the most important ones are sodium hypochlorite, about 6 percent would be a proper concentration. You can get pool Clorox. It’s closer to 8, 9, and 10, but you’re gonna get a lot of corrosion of these tubules. You get a lot of artifacting, and you get a lot of undesirable erosion. So, you don’t want that. So, sodium hypochlorite, 6 percent, EDTA 17 percent aqueous, EDTA. Those two chemicals are the back bone of clinical endodontics. That’s all Ruddle uses. There was a question in the back. “What about QMix? What about MTAD? What about SmearClean?” Don’t use ‘em. If you feel you need to, then go right ahead.

On the last part of this show, we’ll do a segment on calcium hydroxide. That’s been used as an inter-appointment medicament for a long time. Basically then, that’s the reagents, two. There’s others. Then we have mechanical energy to agitate solutions. I’ll talk about this another time. I already have. This would be like – an example would be GentleWave. That’s light energy. And then we have laser energy. And laser – this is sound. I’m sorry. MultiSonics is sound energy, and this is light energy. So those will all be talked about over and over, because they’re important technologies that are ever changing. Prices are coming down, more competition’s coming in. So, we’re gonna see a big reshuffle in here.

Whatever it is that you choose to use, you should ask yourself three questions. Is there evidence – is there scientific evidence behind what I’m doing, in peer-reviewed journals? The second concept is collaborative evidence. It can’t be a paper or two. It can’t be five papers from one school and a team of people. It can’t be papers from people that have financial conflicts and are on the Board of Advisors. It’s gotta be genuine, sincere, academic research. Is it easy to use? Is it something you can go home and incorporate into your already-successful technical skills? Or are you gonna have to retrain, shut the office down, go take training courses, get up in the air, fly places, spend a lot of money? Or can you just put it to use?

Finally, I would imagine, and this is a relative term, because what’s affordable for some might not be affordable for others. In other words, we have lasers for $100,000. I’m not teaching stuff that a handful of people can use on their best days. I’m not talking about $70,000 technology, where there’s a limited potential, a very limited potential. I’m talking about something that the masses can use and really up their game and get you closer to the rim, to use a basketball analogy, so you can play above the defense. So, I’ve written a lot of articles about this stuff, and you can look at ‘em. That’s just one little paper. Let’s take a look.

The most frequently used, historically, traditionally, has been ultrasonics. Ultrasonics has been what dentists use to agitate. The problem with ultrasonics is multi-faceted. But first of all, people are really impressed by massive numbers: 40,000 hertz, 40,000 cycles per second. You’re going, “Wow!” Some of the other devices seem like it’s a turtle, it’s going so slow! It’s going so fast! So, they think, “Fast is good.” Fast is completely unrelated to cleaning. If you look at the frequency, you can see, if this was the X axis, the frequency axis, we have a very fast back-and-forth cycle. So the frequency is the time it takes a pendulum to go through one complete back-and-forth cycle. Start here, back to the beginning, that’s the frequency, one cycle. So, very, very fast. What’s important? Has also no amplitude.

So if you look at the prognostication for cleaning a root canal system, the mathematical formula is said, “Streaming velocity is related to the frequency. It’s related to the amplitude. And it’s related to the radius.” Some groups in the world like to work on frequency, because they’re enamored by speed. I won’t name the company, so I don’t embarrass them, because they’re teaching you to destroy roots. But some people are interested in huge amplitudes. The radius of your tool has to play a role. And Walmsley and Lumley, years ago, described all this for us. So, I just got close, and there we go. Now – I got close to the screen, and it moved, inadvertently. Okay.

So, here’s the problems. By definition, ultrasonics must drive a metal insert tip. Metal on dentin means mud. Metal on dentin means mud. Even if we use non-instrumental technology, that means we use blank metal versus cutting flutes, like a 15 file is an example, both will cut -- the 15 file will cut much faster. Then, there’s active and non-active. I just mentioned, you can have flutes on a file that actually cut. That’s very, very bad. And even when it’s blank, it’s dangerous. We make ledges, we perforate roots, we break instruments, we destroy canals. Do I need to go further?

And dampening, what’s dampening? Well, if 2 Alpha is a pendulum, so it rests, swings out max, this angle is alpha, that angle’s Alpha. So, 2 Alpha represents your back-and-forth, linear motion on your ultrasonic tip. When ultrasonic instruments, because of multiple nodes and anti-nodes along the energy wave, you lose 2 Alpha. Then, all of a sudden, you’re doin’ this, instead of this! So, it dampens. So what did I just tell you? When you’re in a curved root, and virtually all teeth, the roots are curved, and some are significantly curved, and some of them are multi-planar curvature.

What I just told you was, when the tip of that instrument or any lateral aspect of that active part touches dentin, you lose 2 Alpha, you dampen, and you’re not even getting the agitation that you’re imagining. So, there’s a big fat, we don’t do that. So just to bring it home, so you don’t miss it, this is, I think, an exquisitely shaped canal. It’s a tough one to do in plastic. If you don’t believe me, take a workshop and try it. But ProTaper Gold can do it beautifully. That’s a 25 tip, 8 percent taper, can find it right here. And then, we have, you know, the regressive tapered file that we’ve talked about in this segment.

So, let’s put an ultrasonic instrument, the file adapter bolts it onto your ultrasonic handpiece that has a generator behind it, and let’s use the protocol. The protocol is 3 cycles of 30 seconds each, 90 seconds. Let’s go! So, what we did is, the first 30-second cycle was a 15 file, attached to an ultrasonic generator, the P5 by Dentsply Sirona. You can see how the shape is already changing, visibly, and you can begin to see, we’re ripping and tearing, we’re completely making debris. Remember, we were supposed to be using ultrasound for disinfection, and one of the ideas was to remove the smear layer. But you could see, it generated its own smear layer, destroyed the model.

So, we stopped at about a minute. I still had another 30-second cycle to go. So, if I would’ve kept going, I might have been able to really give you something that could’ve caused an international roar of laughter. So, let’s review. Ultrasonics is in the gold-colored letters, and you can see, it’s very fast, tremendous back-and-forth frequencies, but almost no amplitude. Sonics is very, very slow, but it gives us tremendous amplitude. Hey, are there any surfers out there? Come on! This is logical! Does anybody think they can surf the gold line? No! Surfers wait for waves to build! Then they get on their leading edges, and they catch the wave!

So, you can see, sonics, there’s no dampening. You get your full 2 Alpha. That tip, it’s blurry, but we can track it. It's moving about 5 millimeters, through 2 Alpha. Now, obviously, when you stuff 5 millimeters of 2 Alpha into a narrow orifice, and a funnel-shaped canal, you’re going to restrict 2 Alpha. But guess what? You get a lot of mechanical energy on those walls. That polymer tip, non-cutting tip slaps those walls! Just like your bristles would break up debris and plaques on your teeth, because the bristles collapse around an irregular surface, and you have more bristle-tooth contact. You improve that.

So, we’re getting a lot of 2 Alpha. Notice when we bend the instrument almost at 90 degrees – here’s the long axis of the handpiece, and there’s the tip, notice the tip is still moving vibrantly. Now, it’s moving a lot because there’s one node and one anti-node. So for those of you who wanna read about it, you can go to my articles. But ultrasonics has multiple nodes and anti-nodes. Sonics has one node and one anti-node, and that’s why we don’t get dampening. So you have a polymer tip, won’t cut dentin, won’t break, won’t perforate, okay? No iatrogenics. We have three tips. Choose a tip that will go within two millimeters of your working length, loose. Say it again. The tip must be loose. If the tip of the instrument is frozen, it can’t go through 2 Alpha.

So go down within working length, two millimeters short, and it needs to be loose. If it’s loose at two millimeters, you’re going to get everything. Today, I’m just gonna talk about the top button. That’s disinfection. This is the bottom button. And we push this bottom button to reduce the speed, for calcium hydroxide placement and removal, and MTA, to move it into root defects. So we activate it at 10,000 cycles per minute. It’s pretty slow. But what happens is you’ll get wave movement, and wave movement becomes so violent that it breaks the wav, and at the liquid interface, bubbles form. The bubbles are unstable because of heat and pressure, and they finally collapse and implode, and they send out shockwaves. So every 1 single bubble sends out 30,000 shockwaves.

So, the EndoActivator works by bombardment. It works by moving things, violently, inside the root canal space. And that’s why we want deep shape. If you have deep shape, that holds our reagent inside the root, unlike GentleWave, where they talk about minimal instrumentation, more parallel apical thirds, more likelihood that solutions can be moved through and beyond the terminus! So, we vacuum out the loose debris, and you have a root canal system that can be three-dimensionally filled. And you know what? You can do that all in a minute and a half.

So let me take you through it, real quick. So, you shape the canal in the presence of sodium hypochlorite, about 6 percent. When you’re all done with your shape, you take out your file. You know you’re done, because the apical flutes of the file are loaded with debris. Clearly signals, this file just cut its shape in the apical third. Done with shaping. Now we disinfect. Take your irrigating syringe, pull out all the reagent, sodium hypochlorite. Put in EDTA, 17 percent. Activate. One minute [makes burring sound], okay? You’re causing fracture, bubbles are forming, implosions are occurring, and you do that for one minute, by the clock.

Then aspirate all out the EDTA. It’s gone. Top off with sodium hypochlorite, 6 percent, 30 seconds. 30 seconds of activation. It’s a minute and a half per canal. A molar, six minutes. Well, if you had four canals. So on the last slide, I said to you, you should pick something that is what? Evidence driven. I said you should pick something ideally that is affordable. I said you should pick something that’s easy to use. The EndoActivator’s cordless, works on a battery, okay? Two A. And I’m just showing you a few papers. If you go to my website, you can see 19 papers. You can see some papers that are in progress around the world, because residents are always doing research. But these papers are all peer reviewed, no trade journals.

The father – one of the fathers of QMix, Haapasalo, used the EndoActivator to validate QMix, and it became a commercial product. He mentioned how good it was. I won’t go through every paper. Kanter and Weldon, Pileggi compared ultrasonics versus sonics, directly, head to head, and they found out at the three-millimeter level, there was more clean lateral canals with sonics. When they had a control group, they used for obturation, they filled into more discernible, lateral canals, with sonics as compared to ultrasonics. So sonics was statistically significantly better and not iatrogenic.

We have things that compare it now with more sophisticated stuff. And now we have even some analysis here with lasers! And we looked really good! So for a tip in the United States that costs $1.80, can I round it, $2? So, for $2 a patient, and for about $550 for the introductory handpiece, which is all you’ll need, and if you can take care of it, and don’t drop it, or think it’s a basketball, I still have my first one, that I had 15 years ago. Bob Sharp, my partner in all this, Dr. Robert Sharp, from Sacramento, he’s now retired, but he helped me with this whole concept, all the way through, he still has all of his original ones. So he changed batteries.

So what’s my message? You know in real estate, it’s what? Location, location, location. In endodontics, it’s about cleaning, cleaning, and cleaning! And to the extent we clean root canal systems, we can experience the thrill of the fill. Good wishes on your future agitation method.

Okay. So today we have another “Fresh Perspectives” segment for you. If you remember from our first season, this segment is designed to get you to think of something a little differently than you maybe have, up until now. We often accept ideas without really questioning them. So this segment is to get you to think outside the box, break down paradigms, that kind of thing. So, if you remember from our first season, we discussed if there was really a difference between a ledge and an apical seat. But today, we’re gonna talk about the measurements involved when we talk about minimally invasive endodontics and how significant or not these measurements actually are.

Oh, very good. I guess you gave me a fastball right down the middle of the plate, belt high. Of course, noble – the nobility of minimally invasive anything is something that gets all of our attentions. We remember sports injuries, where they used to open up the knee, and the convalescence was very long. And then we made three incisions, put a camera in, the cutting tool, the aspirator, and all of a sudden, convalescence went very quick. So to start off with, I want everybody to know that Ruddle really believes the concept of minimally invasive endodontics, and it’s noble to preserve dentin. But sometimes, we’ve gotten so carried away with minimally invasive endodontics and what it might mean, that it has become, in my opinion, very, very commercially driven. Let me explain.

In 1995, Pierre Machtou, Professor Machtou, Dr. John West, and I came together, and we went to Ballaigues, Switzerland, to begin working on the file called ProTaper. And we didn’t even know the words “minimally invasive endodontics”, but I want the audience to look at what we ended up with. So when we launched in 2001 some years later, you can begin to see John West’s idea come to fruition. John’s idea that you would change the taper on a single file, not between or among instruments, but on a single file, the taper could be progressively increasing tapered, or it could be progressively decreasing tapered.

So if you look at these 2 files, and you look at a 25.08, that’s the F2, that’s a ProTaper Gold finishing file, you can see it has a tip that’s 25/100ths, you can see that it has a regressive taper. It’s written under its handle. And so, we end up on the back end or what we would say the diameter, D16, just a little over a millimeter. As you’ll see in just a few moments, when we start talking about differences of 6/100ths, 8/100ths, or even 1/10 of a millimeter, between and among files, it’s nothing. Dentists can’t even live in a world of a tenth of a millimeter. But the – we can always aspire to.

So if you look at the bottom, that would be a fixed tapered file, where the 8 percent taper runs out over 16 millimeters of cutting blades. The taper alone would be enormous, before you even add the tip diameter. So if you think of a file that is 8 percent, that’s 128, and we haven’t even gotten to the 25 plus 128, to get to 153. That’s bigger than a Gates Glidden GG #6. So before we ever knew the words, we were aware that we needed to have smaller bodies. We had to worry about not only internal anatomy, but we had to think about external tooth anatomy and the concavities and stuff and how the shapes from internal begin to encroach on concavities.

So we were aware, back then, intuitively, just because we’d practiced already for decades, that it would be wise to have a file that would be a little smaller in the back end. All right. So we have a table here, and let’s not get too caught up in all the numbers. Numbers are so boring. But I’m trying to make a point. When is minimally invasive dentistry or endodontics or files in particular, when is it of some, you know, value, that we all stand up and go, “Whoa! That gets my attention!”? 20.04, most people realize, unless maybe you have a GentleWave, you can’t clean those small, conservative shapes. But some people still like ‘em.

So you can see that it – at the diameter D0, the file’s a 20. You can see 3 millimeters up, it’s about a 32. And you can see the numbers 9 millimeters up, just look at the file over here, and you can see D0’s the tip of the file. That’s the cross-sectional diameter, D3, D9. I skipped a little bit, in here. And then we pick the file up, 9, 12, and 15. So, you can see, it’s pretty small. But if you look at a 25.06, which is really a popular file in the world of endodontics, the favorite file, by many, many surveys, by the American Association of Endodontists, has been a 30.06. So, an 06 taper is 32 times 3, that’s 96, and you haven’t even added the tip on. That’s 30.

And you can see, you get to some pretty big numbers, 1.20, that’s bigger than a GG #4. If you look at a regressive tapered file, you see the asterisk there. You can see that we only have a fixed taper in the front end, and only for the first 3 millimeters can you add 8 and 8 and 8 and get to 49. So, 25 and 8, and 25 and 8, and if you keep going and get to 49. But you can see, then, the tapers begin to be regressive, and at the back end, the file’s just a millimeter. That’s a way to have your cake and eat it, too. You get the deep shape. It allows your irrigants to circulate. You can warm gutta-percha and mold it into these configurations, but yet, the body of the canal is kept purposely smaller than usual, so we can preserve dentin.

So, you can see that a 30.06 and a 25.06 are considerably bigger than a regressively tapered file. So a lot of these numbers that we banter around, colleagues have no idea. Does the file have a centered mass of rotation? Does it have an envelope of motion, where the file’s small, but it makes big envelopes, and cuts a full shape? So people never talk about, well, was it centered rotation, was it offset? They don’t really talk about fixed tapered versus regressive tapered. So there’s a lot you can just learn, here. This has all been published stuff, so you can look it up.

If we try to take this to a tooth, so you begin to understand the concepts, you can see along the file, we’re seeing the diameter 3, 6, 9, 12, 15. And you can see that the taper on this instrument, this is WaveOne Gold, as an example, it’s 7 percent in the front end -- fixed tapered, 7 percent, and then the tapers get 6 and 5 and 4. So the file, to your eye, is looking like it’s getting bigger in its cross-sectional diameter. But it’s getting bigger at a smaller rate. So, let’s look at this tooth now. Let’s get into the teeth a little bit and apply file knowledge with tooth knowledge. So clinical crowns are about 10 millimeters, right, everybody?

So, teeth are about 19 to 25 millimeters in their overall length. So if you did a bell curve of all the extracted teeth on Planet Earth, you could put about 80 percent of ‘em are 19 to 25. If you subtract 10 millimeters, the clinical crown, roots are about 9 to 15, and you can begin to see if you break roots into coronal one third, middle one third, and apical one third, each third is about 3, 4, or 5 millimeters. Okay? So, how does the file relate to that? People always wanna talk about the diameter right here. Frequently – frequently, we never even have these flutes below the orifice, okay? The flutes never even go below the orifice.

So the part that we should really focus on is that part of the file, the active portion. It is actually what? Going to be cutting its shape. So if you know about how teeth are about 9 to 15 on the roots, and you think about then, roots are 3, 3, 3, or they’re 5, 5, 5, or 4, 4, 4, the magic numbers are about 85/100ths and 1 millimeter. That’s the part of the file that’s actually going below the orifice. So it’s reassuring to know, those are considered really conservative shapes, and this is WaveOne Gold. ProTaper Gold’s even smaller! I really like this case. I think I have to stand up.

We always talk about the rule of thirds... a third, a third, and a third. This is about a quarter. So the biggest you’d wanna shape is about a third of residual dentin, radiographically, in a two-dimensional picture, another third over here, and the biggest you’d wanna be is maybe out to about right in here, another third. This is very conservative, and this Howard guy, he’s a pal of mine, he’s a really great endodontist, and his comment to me was, “What’s the big deal with GentleWave? If those colleagues would get a great, deep shape”, he said, his EndoActivator would clean this out in a minute and a half and look at the thrilling anatomy!

Lisa, how many portals of exit do you see? Maybe we can count them. One, two, three, four, five. Five POEs, all in the last three, four millimeters. Thrilling stuff! Done with a 25.08. So, he could get the big, full, deep shape in the apical third, to exchange active irrigants, clean laterally, fill root canal systems with vertical condensation. But look at the body. It’s conservative, and he left a lot of dentin. So, you know, this is kind of a very short segment on this topic, minimally invasive. I might wanna add for our audience that minimally invasive endodontics is dimensionalist. You can’t find anywhere, in any literature, peer reviewed or, you know, regular magazines, trade magazines, nobody has any dimensions. It’s just “small”, “small”.

So, colleagues started getting fearful about, “Am I too big? How small should I get?” Remember, you gotta keep three things in mind. Shaping facilitates cleaning and shaping facilitates filling root canal systems. So when you change one of the three legs, you change everything. So finally, when you look at well-filled canals, furcal canals, multiple apical portals of exit, keeping the bodies conservative, with a nice, full, deep shape, it kinda reminds me of this. Let’s come back and look at a human hair! So please, on your machines, put in “human hair, forward slash, dimensions”.

What you’ll notice that a fine human hair is defined, on the net, as 6/100ths of a millimeter, and I go, “Wow! I’m an endodontist! There’s a significance there! There’s a correlation!” And then, I looked, and I saw, “Oh, a medium hair’s the size of an 08 at the tip, at D0. And a really coarse hair is really a 10th of a millimeter.” So if you went back and looked at the charts that I showed you, and if you think about all this, you could say that oftentimes we are ferociously battling in the marketplace, “Buy my file!” “No, buy this!” “Oh, don’t buy that one! That one’s really big! That’s blowing out lateral dentin!” “It’s infringing on furcal. Danger!”

I think oftentimes, we can make it really simple, all this confusion and all this misinformation and all this tryin’ to be really noble is nothing more than splitting hairs. So, I’ve done all the talking. I think you should be, as a non-dentist but my wing-woman, and a very knowledgeable person in endo, what did you get out of all this?

Well, I’ll try to explain what I’m thinking when I watch this. It seems that the file companies must be making a lot of files, that they claim are in line with the concept of minimally invasive endodontics, and if you use that file, you’ll achieve a minimally invasive shape. I think, though, that the clinician should start with the shape in mind and then choose the tools or the files that will help them to achieve that shape. So, is – like what I’m saying is that we can rely – we can’t 100 percent rely on the tools to make up for any deficiencies in training or that – we need to actually go with trying to create the shape that we have in our mind that’s appropriate for the anatomy involved.

So, for example, like if I saw – if a clinician shaped two similar canals, one with maybe a progressively tapered file, and another with a fixed tapered file, maybe – a small one, maybe having to use more brushing, that the end result, if I’m looking at radiographs, side by side, I’m thinking that those shapes should look pretty similar. Like, you created the same kinds of shapes, even before there were variably tapered files and all of that. So maybe what is happening is, we need to focus less on the hair-like measurements that are differentiating files and focus more on what kind of shape we’re trying to create, like go back to the basics, like – I don’t know.

I’ve told you before, like maybe you should try to do the kind of shape you want, with the crudest technology, and see if you can achieve that. And then once you’re good at that, then, use a technology to help you, but don’t rely on the technology necessarily.

So what I heard you say, if you were Post-Graduate Chairman at my alma mater, all the incoming dentists that are now residents, you would have them, for probably a significant amount of their first year, learn how to use six, seven, eight, nine stainless steel files and three or four GGs. And when they get that all mastered, and they know how the shapes are supposed to look, and they can judge it, and their classmates and all that, then, maybe we can turn ‘em onto some technology. But they’ve mastered the underlying skills.

So I guess my close would be – thank you. I liked what you said. But you know, I travel quite a bit. So you know where the beautiful game’s played. It’s in Brazil, and it’s called soccer or football! And we always say, when we’re down there, “It’s not the ball. It’s the foot.” And in America, we have baseball, and “It’s not the bat. It’s the batter.”

Well, thank you. That’s some great information. And maybe we’ll all be thinking a little bit differently now, when we’re choosing files to create the shapes that we want to create.

So we’re going to close our show today with a little Q and A. And you’ll see that the kinda central theme of the questions today, there’s two of ‘em, are calcium hydroxide. So, ready? Ready for your first question?

Ready!

Okay. So a little earlier, you mentioned the EndoActivator as a method – as a sonic disinfection method. And in fact, there are over 90,000 clinicians, internationally, is it, that use the EndoActivator for disinfection. And additionally, there are 19 peer-reviewed papers that support the EndoActivator as a disinfection method. But I know you’re asked a lot, what other ways can you use the EndoActivator?

Want me to ask you? Because you helped me write all those chapters that went in international textbooks around the world, that we identified in non-surgical retreatment several applications.

I can only name one, off the top of my head. So, maybe you should answer the question [laughs].

All right. Well, you know, we’re gonna talk about this a little bit more, but calcium hydroxide. So, placing calcium hydroxide and then, of course, on another visit, or the same visit, if you wanna remove it, many studies have shown that probably the only way you can completely get it out, especially the eccentricities off the rounder parts of canals and fins and stuff, is probably through sonic agitation. So it’s used to not only – then help adapt it but to remove it. MTA, mineral trioxide aggregate, is a fabulous way.

I used to work on construction when I was a kid. So we did a lot of concrete work in big buildings in Oakland and Berkeley, and I was the guy that ran the vibrator. And it was a big hose that went to a compressor. And at the end, it had what we called the dong, and it was about that long and about three inches in diameter. And that would vibrate like crazy, and we’d make the mud go around the rebar, that’s the steel, so that we got a really tight form. When we took the forms off, 30 days later, there were no voids. So we can use the EndoActivator in MTA, mud, and we can move it into root defects, into immature apices, and so, it’s a wonderful way, without using a packing motion, to vibrate it and have it move through ultrasound, right down into the anatomy. So those are two ideas.

You know, a lot of times, you invent something, and then, you find more applications. So, those two, I was aware of before we ever came to market. So, disinfection, MTA, calcium hydroxide. But as a clinician, I taught for years, every time you take a file out of a tooth, a mechanically driven file, you do three things like religion. So there’s the great religions on the Earth, and then, there’s endodontic religion. Always, when you take out the file, you’ll notice debris on the file, if it’s cutting. Then you irrigate, to flush out or kick out gross debris.

A lot of you, then, miss a couple steps. You go right back in, with the rotary file. Take a 10 file, go to length, work it up and down in little, short amplitude strokes, and move that debris in the solution, and then, re-irrigate. So said slowly, after you remove a file, irrigate, recapitulate, irrigate. As soon as I have sufficient taper and some shape going, I don’t use the 10 file, I use the EndoActivator, because it doesn’t cut and the Delrin tip is as a palmar. It vibrates and hits the walls, breaks up debris, moves the debris in the solution, and it’s much kinder than a metal file. So I can use it between instruments, all through the normal shaping procedure.

And finally, many times, everybody around the world has noticed this, you do a nice shape, your file’s going right to your working length that you’re pretty sure is accurate. And then, you go to fit your cone, your cone’s short, or it wrinkles, or whatever. So you want to, quote, adjust the preparation. It’s easy to take a file, load it up, go down 1,000, 2,000, 5 seconds, you’ve modified your shape a little bit. Use the EndoActivator, irrigate, recap with the EndoActivator, and then, irrigate and liberate that debris. So I can use it very easily, all through the procedure.

Contrast that to, I’ve been watching a lot of GentleWave procedures. And they take the platform off, and they go to fit the cone, or whatever they’re doing, and if the cone doesn’t fit, which sometimes it doesn’t, just said that, then they’re not putting the platform back on and going through another eight-minute cycle. So what about those files that go back and adjust? They’re making another smear layer. So, those are four ideas.

Okay. Back to calcium hydroxide, and you are asked a lot about how it’s used, its applications, and its delivery in endodontic treatment. But what are, specifically, these applications, and how do you introduce and adapt this material clinically? And are there dangers, placing calcium hydroxide?

Good. Okay. Get right at it! So obviously, I think in today’s world, 2020, internationally, we’re – well, most of us, the vast majority or all dentists, are trying to schedule for success. And that means one-visit endodontics. But there are plenty of cases that can’t be done in one visit. What comes to mind immediately is retreatment cases, where you’re taking out a post and a core, and you’re dissembling the whole tooth. And maybe you have time to continue on, or maybe you would like to have an interappointment medicament, and it would be calcium hydroxide.

So the pH on calcium hydroxide, the hydroxyl ion, the OH ion, is the really basic component of calcium hydroxide. Most reactions in the bone secondary to infection are acidic. So when you have a really high base material with an acidic environment, it tends to neutralize that acidic environment, and it can be useful, then, in the interappointment visit, between visit one and two. You might put it in – okay. You can put it in, in a lot of different ways, but most companies sell radiopaque calcium hydroxide. It’s not as opaque as gutta-percha, but it’s definitely visible on a film. So there’s syringe systems and screw guns, systems with variable length and gauge cannula that you can screw and drive the calcium hydroxide into the canal. I used to do that a little bit more – maybe we would call it, in today’s world, dangerous, up to about 15 years ago.

And then I had the EndoActivator. So what I do is just put calcium hydroxide in the coronal one third. I’m not trying to put my cannula really deep, and I worry that I might get an extrusion, inadvertently, especially in the mandibular region, mental foramen, neurovascular bundle, mandibular canal. So, you can use vibration to sputter coat and throw it around on the walls, take a postoperative film, and if you see some opacity through the canal, you’re not trying to pack it wall to wall. You’re just trying to change the environment.

So it’s really good in two-visit endodontics. It’s really good to put out bleeding, so it’s a hemostatic. And what I would do with a hemostatic is – well, it depends on the extent of blood. If blood’s just pouring up out of the canal, I might syringe some into the coronal one third and then do what I just said with the EndoActivator. But if it’s just a little bleeding down the last three or four millimeters, I just butter a paper point with calcium hydroxide, and run it up to length, little gentle in-out strokes, pick up a little bit more. And then, what I’ll do is, bye-bye. I have to leave the room, because it’s hard to sit on your hands for five minutes chairside, unless you have stories, and you know your pop has stories. So, chair – staying [laughs] chairside --

[laughs]

-- for 10 minutes was perfect. Anyway, you come back in five minutes, use the EndoActivator, break that up, get it out, eliminate it, and then see if you can dry the canal. Usually, after one time, you can dry the canal perfectly and go ahead and pack.

If it bleeds, I’ll do that a second time, put it in, five minutes, come back. If it’s still bleeding, I put it in the canal, provisionalize, bye-bye, and it’ll be a second visit. I have never seen a case, except I don’t know, less than 5 times in almost 50 years, where it still bled the next visit. And sometimes, then, you have to think about resorptions. Speaking of resorptions, that’s another reason we use calcium hydroxide. So I mentioned we use it in two-visit endodontics. We do it to change the environment. We use it in vital or necrotic cases. Most dentists would say, “Necrotic, that’s my favorite.”

But, you know, it’s been shown in the literature that on vital cases detached tissue is necrotized by calcium hydroxide, which means it makes it easier to flush out on a subsequent visit. So I mentioned resorption, I mentioned bleeding, I mentioned apex location, I think. No, I didn’t. But in immature apices or blown-out apices or apices that have been ripped and transported, all these are segments we’re gonna show you on live patients. So this is just laying some framework so, when we get to it, you’ll go, “Ready!” All right? So, I think the dangers – dangers. There was a really nice paper that came out in the Journal – the American Association Journal, JADA – “Journal of the American Dental Association”, for international guests, so you’re up to speed.

We’ll have it for you in the show notes.

But Gluskin, the Al Gluskin, from the University of the Pacific, Christine Peters, the more famous one --

[laughs]

-- everybody thought it was Ove but it was actually Christine, the endodontist. No, they’re great people. And then, of course, there was a guy named Lai, Gordon Lai, I think is his name, and they wrote a paper, “The Double-Edged Sword of Calcium Hydroxide”. “Double-edged sword” already tells you, there’s some really great purposes and uses, but there’s a double-edged sword!

So in this paper, they show accidents, and they’re virtually all down in here. And it’s because people are pushing and pumping and trying to use hydraulics. And this is not how you use it. So, again, you can syringe it in. I said, “coronal third”. You can get it in. But the main thing is, get the – get it in. And then as you start to syringe, be withdrawing the needle! Don’t hold the needle in and keep syringing! That’s hydraulics! So, you’re coming out, as you squirt a little calcium hydroxide in.

Would you say that these accidents that are happening are just pretty rare? Or are they happening maybe more often than they should be? [laughs]

You have better eyes than I do, but how many references are at the end of this paper? I think you have to go to the last page.

Yeah. I see 60.

60 references. So, a lot of those were showing the virtues of calcium hydroxide, but the question was, “How frequently does this occur?” I don’t know what the incidence is, but the paper clearly outlines it happens right along, and because they get involved in these things, they’re at a university. So, if Luskin sees a lot of crazy cases, burns, thermal burns, different kinds of injuries, and he – you know, him and I wrote a paper some years ago about thermal injuries secondary to ultrasonic procedures.

So I don’t know what the frequency is, but I’ll tell you, they talk about anesthesias, paresthesia, and dysesthesia. And all these -esthesias are not good, and most of them are regrettably permanent. So if you’re gonna have a problem, you need to have an endodontist and a maxillofacial surgeon on your team. You need to be able to make a call, because the most important thing to mitigate all that is time! And it seems like less than 48 hours is really important. Otherwise, pretty much, you can be drooling the rest of your life, you can be numb, you can’t feel. And it gets really pretty sad that something went that wrong, when something could’ve gone so well.

Okay. Well, those were good – a couple good questions. Thanks for those answers. If you want to ask a question that you want us to answer on the show, then, you – here’s the information for – to submit the question. And you can also let us know if you want us to tell who asked the question or if you wanna remain anonymous.

But most importantly, questions are the answers.

That’s our show for today. Thanks for joining us for The Ruddle Show.