It is generally recognized that root canals can be predictably prepared when shaping files have a reproducible and sufficiently-sized pathway to follow. The secret to shaping success is glide path management (GPM)...
Q&A and Recently Published Articles Glide Path/Working Length and 2 Endo Articles
This show opens with Ruddle sharing his views on the now controversial topic of Daylight Savings Time…if he doesn’t arrive an hour late. Next, Ruddle does another Q&A, this time focusing on glide path management and working length. Then, Ruddle discusses 2 recently published articles and their relevance. Stay tuned for the close of the show where Ruddle will present a couple novel case reports from his collection of all-time favorites!
Show Content & Timecodes00:10 - INTRO: Daylight Saving Time 04:46 - SEGMENT 1: Q&A - Glide Path & Working Length 25:58 - SEGMENT 2: 2 JOE Articles 41:08 - CLOSE: Case Reports
Extra content referenced within show:
Extra movie/video content:
Downloadable PDFs & Related Materials
Clifford J. Ruddle, DDS, examines why glide path management is the key to successfull endodontics...
Ruddle Glide Path Management Technique Card featuring ProGlider (rotation) & Gold Glider (reciprocation)
Featured JOE Articles referenced in the Show - Reference & Abstract Information
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: Daylight Saving Time
Welcome to The Ruddle Show. I’m Lisette, and this is my dad, Cliff Ruddle. How are you today?
Well, it’s true that Daylight Savings Time went into effect this past Sunday morning, and we sprung forward. So, we lost an hour of sleep. So I spent most of my day feeling disoriented. What about you? Did you have any adverse reactions to the time changing or maybe any reaction at all?
Well, I noticed it was very cold and very dark, when I went out to do my walk. It was like they say that it’s never darker before the dawn of light [laughs].
Yeah. And did you change all the clocks, or did Mom?
I actually changed most of them, because I go upstairs, and that’s where most of the clocks are. We try to have a clockless house.
Anyway, yeah. I mean, if you look at it, though, there’s some reality to it, the joking, because Circadian rhythms do influence fungi, microorganisms, humans, animals. And I was looking that they all are on a 24 circle of the world, 24 hours, 1 cycle. And so, yeah. We probably do feel a little disoriented, if you’re on a schedule.
Yeah. I know there was some confusion on our last show, when we did our “Good News, Bad News” segment about Daylight Savings Time. And I noticed that you were just setting your watch forward, right before we started our show today [laughs]. So anyway, there is --
-- [laughs] – there’s some issues about it. But I always remember it, because we spring forward and we fall back.
And I’m just kinda used to it now, at this point. I don’t really have a preference. I get up early in the morning, so – I get up when it’s dark, anyway, and so, it’s dark still when I get up. But it doesn’t really bother me that much. What about you? Do you like it to be lighter in the evenings or lighter in the mornings?
Both. [laughs] In other words, soon we’ll evolve towards summer, you know, spring and summer. And we’ll have longer days, so we’ll have light on both ends, no matter if you get up at 5:00 – 4:30, 5:00, it’ll be light at 5:00. But right now, we have to wait for the morning to back up a little bit more, so it’s still light. So, yeah.
It’s been a little painful, going – I’ve had to use my flashlight the whole time on my runs in the morning, the past couple days [laughs].
Especially when we saw that recent sighting of all the mountain lions in Santa Barbara that are down – these – all these cameras and surveillance cameras are picking them up, stalkin’ around back yards and garbage cans and stuff. So [laughs], yeah.
You know, I actually thought about that because when I was out, I’m like, well, gosh, I just actually saw a pack of coyotes recently.
I know [laughs].
And by a pack, I mean five. And so, I was thinking, well, gosh, now I can’t even see them. But are they still there?
Well, they have their Circadian rhythms, so we don’t have to worry so much.
Well, I guess this is actually kind of a controversial topic. I know it’s been on the ballot a few times in the last several years, that some people are very adamantly opposed to it.
Do all states do it?
Well, to back up just a little bit, it’s kinda funny, the German Empire did it in – two years into World War I. They were the first country in the world to do it. They wanted to reduce artificial light, minimize artificial light, and of course the fuel savings. But yeah. Arizona and Hawaii, to this day, have – they don’t observe Daylight Savings Time. They’re on Standard Time.
Okay. Well, I guess I don’t really – I’m not going to those states anytime soon, so I won’t have to worry about what time it is there [laughs]. Well, in case you didn’t notice, it is St. Patrick’s Day. Our set looks kind of greenish, and I’m wearing green, and you have a little green on your tie. So --
Yep. I can’t be pinched today!
-- [laughs] I know, it’s – actually, that’s why I’m wearing green, just primarily for safety reasons, because I don’t want to be pinched. And it’s weird that you’re even allowed to pinch people, on a day like this [laughs].
Well, all my friends in the world that aren’t wearing green at this moment, I’m going to pinch you the next time I see you.
[laughs] Okay. Well, we have a great show for you today. So, let’s get going on it.
SEGMENT 1: Q&A – Glide Path & Working Length
Okay. So, here we are for another Q&A segment, and this time it’s going to be about glide path management and working length. So, I have the questions here, which I’m going to read, and you have the answers in your head. So, here we go!
When I can’t get to length with a size 10 file, what do you suggest?
Oh, okay. This is something that I think could be a very useful trick for a lot of people. But if you have a – just a – a natural tooth in here, and we are – just pretending. And then, we might have some pathology and we might have a wrap-around lesion. So, we have this maybe little curve right in here, and then, we have a – so, that’s our starting point. So, a lot of times, a colleague will grab their 10 file, and they’ll cut their access cavity. And they’re starting to work their 10 file in, but oftentimes they don’t realize that the rate of taper – the rate of taper is 2 percent. So, a lot of times, you’re thinking it’s a 10 file, but up at D16, that 10 file is a 42. So, it’s 0.42.
So, sometimes the rate of taper of the file is greater than the taper of a canal at this moment. And that means your file could actually be – if this is a cross section through here, there’s your root. This could be your file. Your file could be loose. The file could be loose here, but the file could be binding, up in the body. So, the secret is, if we start to clean this up a little bit, get this cleaned up, we could consider a concept called pre-enlargement. And in pre-enlargement, we talked about that in the ‘70s, so it’s not a new idea. But in pre-enlargement, the focus is to get access into this area where it’s difficult.
Most canals make their curvatures, their divisions, deep. So, if we can just come in here and kinda consider doing this, and then like that, and if we can kinda come in and do a little pre-enlargement and like that, then, I think what we can do is get rid of that and that and that and that and that. Now we have working width. Now we have working width. I’ll put that back, and we’ll put that back, and we’ll put that back. But now we have working width. So, now you have a larger cross-sectional diameter. So, now we can pass the 10 file through a pre-enlarged canal. The file will be completely loose, and now it’ll only be binding in its terminal extent. That is one of the biggest clinical tricks to achieve working length, is pre-enlargement.
Now I just have one question. Would you maybe try with an 8 first, or would you – a 6, or would you just start pre-enlarging?
When I was younger and didn’t know so much, which is pretty much the current condition [laughs], I would drop to an 08, and I would drop oftentimes to an 06, and sometimes at the end of visit 1, we had a whole bunch of discarded 6, 8s and 10s, and it looks like I was in the business of selling files to others. I had so many!
And it took me like about five or six years after I got out of grad school, in the mid-‘70s, to figure out the file’s not binding down here. I don’t need a 6 and an 8. I need to get rid of canyons of restrictive dentin in the body of the canal, and now instruments just slide.
Okay. All right.
We’ll have an interesting case we’ll look at on a case report, to kind of show this concept, a little bit later.
Okay. So, the next question. I have heard you say that once you get to length with a size 10 file, then you can skip the size 15 file and proceed straight to a mechanical glide path file. Couldn’t that be considered a little dangerous?
Yes and no. What a lot of colleagues don’t realize is that the biggest jump in the business, and we could keep going and blah, blah, blah, is right here, between the 10 and the 15. It’s not anywhere else in the series. Schilder pointed this out in 1993, and it was at the IFEA Conference in Paris. And a 10 file, as we all know, really has a decimal. It’s 15 hundredths of a millimeter. But from 10 to 15, the difference is 5. 5 over the first instrument is 5/10ths, and that equals a 50 percent change. So, the biggest jump in the business is 10 to 15.
But if you look at an apical third, and if you take that file one flute through --, if I could draw it. If you just pass the file through 1 millimeter, you’ve now gone to a 12! Because it’s 02 tapered. So, 1 millimeter up, the 10 file at D0 is 10, but at D1, it’s a 12. So, if you take the file through, that’s called patency, everybody. This is what the whole world has learned, patency. Then, you transition the foramen to a 12. So, now you’re just going from 12 to 15, and that looks like it’s 3/12ths. That looks like that would be about 25 percent. So, you can reduce the 50 percent to 25 percent, by just using a patency file.
That wasn’t exactly your question. Your question was – that’s a way to get to the 15 safely. The 15, though, is stainless steel. And because it’s stainless steel, and because of the 50 percent change, it has turned out to be a very dangerous instrument, because people have been trying to get that to length, following the 10. So, we have completely gone away from the 15 file, because it is stainless steel, and we’ve gone to a dedicated – what’d you call it? Minimally invasive technology! That was a word you coined for me!
And anyway, it turned out to be ProGlider. ProGlider came to market in 2014, but ProGlider was conceived in 2003. So, we knew using -- minimally invasive technology, we’ve used ProGlider, which was heat treated, and it’s M-wire – M-wire. This is 400 percent more resistant to cyclic fatigue than non-M-wire NiTi. So, it’s not only NiTi, which sounds like it’s “high”, but it’s supposed to be ‘Ni’. Hi, there! It’s NiTi! Anyway, ProGlider is not only NiTi, but ProGlider is heat treated, it’s M-wire technology. So, you have much greater flexibility than 15. It can snake where there’s a glide path. So, if a 10’s been somewhere, the ProGlider will follow.
Okay. So, I guess the key here is, you have to work slightly through the --
Patency is the trick, because once the canal is patent – well, there’s three things we do when we negotiate. When we negotiate the apical one-third, there are three things we do. Working length. So, you have to establish working length. Two is, you confirm patency. Remember, the canal was patent before Ruddle. So, if the canal’s now blocked, look, Ruddle. That’s a problem. Look in the mirror! And the third thing we do is, we verify a smooth – I’ll write this out, actually. Smooth, and it needs to be reproducible.
Glide path! So, if you have a smooth, reproducible glide path, in other words, you can take your file at length, you can pull it up a rubber stop, and you can just slide it back to length. Pull it up two rubber stops, see if you can slide it back neat. If you could get your head in their mouth, you could push the file to length with your nose!
That’s a loose 10! So, the 10 file is usually the – we’re looking usually at a 10, a 10 file. It could be a 15 or a 20, it depends on the case. But usually, a 10 file we can read radiographically. Usually, we get less false positives with apex locators, when we use a little bigger file. We might talk about that later. So in any event, if you have those three things, that’s what you’re looking for, and the patency is, I usually clear the foramen by about one millimeter, because I learned before ProGlider, before Gold Glider. Those are dedicated glide path files. But before that, we had to the 15, and that was the next step. So, by taking the 10 file through 1 millimeter, we transitioned our foramen to a 12. So, we made that jump 25 percent.
Okay. Well, the next question I’m going to ask is kind of actually related to this. Are there situations in which a mechanical glide path file is contraindicated?
Oh, okay. Well, that’s pretty easy. I don’t even know if I’d change it. Well, I’m kinda proud of this. Our team, Professor Machtou, John West, and myself, coined a lot of the words that are used today in textbooks, in the literature. Other companies use our words! But these were words that actually came from the mouths of three people, because it’s how we thought about it in the ‘70s. But one thing that was coined was “glide path”.
Another one was a “secured canal”. Professor Machtou talked about, “What is a secured canal?” A secured canal is that canal where you can take your 10 file – remember the old nose? -- and you can slide it to length, each time, every time, all the time. When you can do that, by taking progressively longer strokes, longer strokes, you are understanding in your mind, if that stainless steel file can snake through and go to length, then your dumb NiTi file that comes behind it, it doesn’t have a brain, it can’t see, but it’ll just follow the slide path. So, we’ve talked about following, we’ve talked about secured canals. What’s a secured canal? It’s a canal that has a smooth, reproducible glide path, each time, every time, all the time.
So, if you have those three things, you’re safe to use a mechanical glide path file.
And it doesn’t – it’s not – like an extremely curved canal wouldn’t be a reason to not use a mechanical?
Even in quite a bit of curvatures or even recurvatures. Now, I do wanna say, there are manual handles available to clip on these, chairside, and you can convert any rotary file to a manual file by going chunk! And it’s just a few little strokes, and you can pull that manual instrument right where you might’ve been a little afraid. So, if you’re out there, and you’re a little reticent, she said it, it’s more curve, Ruddle can take files around 90-degree curvatures. But I mean, I’m doing it really carefully. But sometimes, it’s manual.
Do the – do the mechanical glide path files also have handles?
Yeah. You can convert them, chairside. And you get a little better shape, because remember, a 15 file – a 15 file is a 15.02. Well, a GlidePath file like ProGlider or like the Gold Glider, this is a reciprocation file. This is a continuous rotation. This is rotation, and this is recip. So, they have much – I mean, they’re two percent in the front end. So, like, from D0 to say, D3, they’re about 2 percent. But then, they start to go three percent, four percent, five percent. On ProGlider, we have eight changing tapers along the active portion. So, it goes from about 16 at length to about an 84 at D16. So, you make a much [with emphasis] bigger hole than this.
So, you have major advantages. NiTi, M-wire, and then it has a much bigger shape than a 15, so it paves the way for your first shaping file. It gives you a bigger pathway. It’s safer.
Okay. So, this kinda – before you erase all this, it kinda brings me to the next question.
Oh, let me try something. I just learned something. He erases, but then, he goes, no, he wants it back!
Okay! There! How about that? Do I get the Medal of Honor?
Okay. So, when using a mechanical glide path file, is it safer to use one that moves by reciprocation or continuous rotary?
Okay. Now you’re going to get me in trouble with – it’s called co-inventors. She’s talking about these two. ProGlider was conceived in 2004, but it took 10 years to get to market. That’s another story that you’ll ask me sometime. Gold Glider was made for the WaveOne people. So, WaveOne is a reciprocation file. 150 is the engaging angle, 30 is the disengaging angle, you net out at 120, 3 cutting cycles. 3 times 120 is 360, and you make – you’re making circles. So, this is making circles, but every time you stop on a dime, come back, stop on a dime, stop, boom, boom, boom, boom, you can start to think of maybe a paper clip, and you start to worry about cyclic fatigue.
So, the angles have been designed in reciprocation to be underneath the elastic limit of the file, which means every engaging angle should be safe. But you – I personally – sorry, Sergio, sorry, Willy Pertot, Wilhelm Pertot, and sorry, Julian Webber, because they’re our team, and we invented this together. I love this file, but I think I would probably go for a continuous rotation in a really small file, because it loads better, it hauls debris better, and it’s a little bit more resistance, in my experience, than the reciprocation glide path. However, VDW just had their file, C-Pilot, I believe it’s called; you can look it up. But they had a peer-reviewed paper, and it showed that it virtually never broke.
So, I think either colleague can be comfortable with either one, would be my closing remarks. If you’re spinning circles, continuously, it’s ProGlider. If you’re using a shaping system, a canal preparation method that’s reciprocation, you should keep the same movement, because Gold Glider works with the same angles as WaveOne.
So, it doesn’t make any sense to have two different movements, like one to shape, but a different one for the [crosstalk]
I would just get really good at something. Like in your sports that you do, you don’t go in there and put on a different gi every time, do you?
Or do you do different routines at – well, you probably do a lot of different routines. But there’s probably certain tenements [sic] that are sacred. So, if you’re really into reciprocation, stay with reciprocation! Get really good at reciprocation.
Okay. I think we have time for one more question. I was taught to work one millimeter short of the terminus, in order to avoid pushing debris apically. Do you recommend this? Which I can imagine, the answer’s going to be no, but [laughs] --
This is just going to be a big ol’ apical third. But we come down, we have -- most of our abrupt curvatures are down in this area. And so, the question was, should we work a one millimeter short? The problem with working short is, first, we should probably understand where that came from. There’s cementum that covers the root, and – so, we’ll just put a canal in here. And the cementum – this is not going to work, but it crawls around and comes up into the root, and let’s just say to that level. The cementum comes around the root and crawls into another level. In other words, the cemental-dentinal junction is not a 90-degree reference point.
It’s a histological reference point, and it varies from wall to wall. So, on the north wall, the south wall, the east wall, the west wall, if we’re using that kind of nomenclature in dentistry, the cementum crawls up in an uneven way. So, histologists recognize this. So now, when you went to dental school, they said, “Wait a minute! How does the colleague work to this magic point?” Because it’s impossible, because it varies from wall to wall! It varies from tooth to tooth! It varies from root to root on a multirooted tooth, and it varies from wall to wall, within one, single canal.
So, the point is, they said, “Well, it’s uneven. Let’s do that!” Some schools say, “Well, no, let’s do two millimeters short!” And it wasn’t very long ago, and they said, “Well, let’s get a little closer. Let’s get a little closer. Let’s have our students work a little closer!” Because there was so much fear about the other side. Listen, it’s a surgical procedure. When you go to length, you’re amputating the incoming neural vascular bundle, and it’s coming in there. And as it comes in, you’re amputating. You don’t want to amputate it short. What’s in here? Well, you’re saying, “Wait a minute, it’s vital! It’s a vital case, Cliff! It bled!”
Well, okay. You’re leaving a stump of vital tissue. The rhetorical question for you is, does it stay vital over the life of the patient? But do all those subsequent files that come into the root, do they start pushing debris and more debris? And all of a sudden, the colleague’s looking at their x-ray, and they’re lookin’ at a file, and now it’s back here! It’s two millimeters short! So, their intention was one millimeter short, but in the process of shaping, over a little bit of time, debris begins to accumulate. It pushes the bigger files back up, out of a canal! And now we end up shorter than our intention.
So, Schilder said the answer was always the same. The answer was always the same. Just work to the radiographic terminus. He called that the radiographic terminus. If you looked at a film, you would wanna see the file right at the edge of the root. If we rotate this tooth around, from another angle, you might see that the canal’s going like this. And so, now the colleague’s going, “Well, let’s the radiographic apex.” This is the radiographic terminus. So, there’s a little discrepancy. Sometimes the RT is a little less than the RA. So, I’m saying, work to the RT with the smallest, most flexible files, but recognize every canal – every [with emphasis] canal is catheterized.
Now we can get our sodium hypochlorite to length. The sodium hypochlorite can work into our tubules. It can work into lateral canals that might be present with lateral root lesions. So, working short has led to blocks, ledges, transportations, perforations, wet canals, okay. Work to the RT. So, we don’t want to over instrument, but we really don’t wanna under instrument. When I say, “over instrument” you’re thinking, “Well, you are [with emphasis] over instrumenting.” Your 10 file’s already maybe sticking out here. Maybe we see a couple flutes.
You know what? You have an immune system out here. You can get in macrophages, nuclear – polymorphonuclear leukocytes. You can get round cells, histiocytes. You can get – you can mount a successful inflammatory response, and your body will repair nicely, if you get out all the tissue.
Okay. So, a little bit of debris going through the terminus is not cause for major alarm?
No, because the body will clean it up.
I didn’t mean to stumble on PMNs, but polymorphonuclear leukocytes are our major defense response in a patient. And if you give a patient an antibiotic, which I didn’t say do it, but if you did, you can get an antibiotic all the way around the root. You can’t get an antibiotic into an avascular root canal system, after pulp death.
Okay. Well, that’s all the time we have for questions today.
But I was just getting warmed up!
Yeah. We still have more. So, I think we’ll continue the second half in --
How many do we have?
-- an upcoming show. We have about five more.
So, we’ll do another Part 2 Q&A on glide path management and working length, pretty soon.
Thank you. And I think now you’re going to present a couple case – or coming up, you’re going to present a couple cases that --
I’d like to.
-- one or two cases that are related to the topics we’ve discussed today.
Yeah. Just a simple case report.
All right. Well, thank you.
SEGMENT 2: JOE Articles
So, every now and then, we thought it would be fun to do a segment on one or two recently published articles that we want to highlight. And sometimes it may be an article that we just found very interesting, and we want to recommend you read, or it might be an article related to topics we recently discussed on our show, or it may even be an article that we find particularly controversial or maybe full of misinformation. So, that said, we chose two articles from the JOE, from the February issue, that we thought were interesting, and we wanted to talk about today.
And the first article is on microcracks, and it is called “Micro-Computed Tomographic Evaluation of Dentinal Microcracks after Preparation of Curved Root Canals with ProTaper Gold, WaveOne Gold, and ProTaper Next Instruments.” And I’m just – there are six authors. I’m just going to say their names really quickly, because I want to be sure they get credit. It’s – and excuse my pronunciation, because a lot of these names are Spanish. Ramon Miguens-Vila, Benjamin Martin-Biedma, Gustavo De-Deus, Felipe Belladonna, Alejandro Pena-Lopez, and Pablo Castelo-Baz. So, why don’t you tell us what this article’s about?
De-Deus and his group has done quite a bit of work on micro-CT work and microcracks. As you’ve mentioned, we’ve done it in previous shows. In this particular study, they gathered quite a few teeth, in the ‘70s, ’76, I believe. But they had to look at every tooth, and they used a stereomicroscope at 12 power, and if they saw any cracks, it was discarded from the study. And so what they had left was three groups, for the ProTaper Next, the WaveOne Gold, and the ProTaper Gold, and they had eight molars in each group. And the molars had to have curved roots. So, the mesial root had to be at least 20 degrees or more of curvature.
Now, for the audience to understand, canals are typically more curved than the roots that hold them. So, that’s the roots that had at least 20 degrees’ curvature. So, we have 8 teeth in a group, 20 no cracks could be visible, 12X, and then, they went ahead and did the shaping. And the idea was with ProTaper Next, they went to an X2, which is – to the audience, that’s a 25.06. The tapers aren’t going to all be the same, and that’s one thing that you would use to critique a study. But in this case, I don’t think it mattered, the way it was done. ProTaper Gold was a 25.08. See, not six percent, but eight percent. And then, ProTaper – or WaveOne Gold was 25.07.
So, what they all had in common is, the tips were 25, and then, the tapers were 6, 7, and 8, depending on which group. And so, then they went ahead and scanned all the teeth, before – this is important – before and after. So, they did it before anybody touched the tooth. And then, they did it after the preparation. And --
With micro-CT, right?
-- micro-CT. So, non-invasive. And they did 35,304 sections. That’s an enormous stack of cross-sectional images. And all those images were looked at, and what they found out is, all the teeth had cracks before anybody even accessed the tooth. So, even though they hadn’t seen it at 12X with stereomicroscopes, all the teeth had pre-existing cracks. 25, 26, 27 percent incidence.
What they found out was that nothing propagated – no existing cracks propagated, and there were no new crack initiations. So, the summation of the study, very shortly, was that using greater taper files, ProTaper Next, six percent, ProTaper Gold – or ProTaper – yeah – Gold, eight percent, and WaveOne Gold, seven percent, none of them caused any initiation or propagation of existing cracks. So, the take-home message was, we can shape canals in a very safe way, if we just follow the DFUs, directions for use.
And specifically, even very curved canals.
Yeah! In curved canals.
So, that is encouraging news. I know that there was some part of their methodology that you found interesting. How to do – tell us about that.
Oh, yeah. There’s always creative things I like to look in the – deeper in the papers. But what he did is, he took these extracted teeth, and he put them in an acrylic resin. And then, he let the resin set up, and then, he got the teeth back out. There was a little pliable, but in the extraction process, the hole’s a little bigger than the tooth. So, then, he covered the roots with foil, aluminum foil, and then put them in. I should say, he put them in the acrylic resin initially, then he took it out. Then, he took off the aluminum. Then he used a polysilaxane, and that’s like a light-body material, and he reseated the teeth. And that was like a PDL. So, I thought that was very clever, how he created a PDL.
So, it’s kind of like creating a situation that would kind of closely resemble --
Like a little shock absorber.
-- because I know that when we talked about microcracks before on our show, we talked about how part of the – one reason how these cracks could’ve showed up was maybe how they were stored, like from dehydration and stuff. So, maybe this protected a little bit from that happening?
Yeah. The audience probably remembers. When we talked about – because -- you’re going to bring this up in a little bit, but the literature was really kind of up and down. If you look at the older literature, instrumentation caused microcracks. That was pretty much a foregone conclusion. The more recent literature, in the advent of micro-CT, said, no, there aren’t any. So, which is correct? So, we talked about the storage, the dehydration process initiates cracks. And then, how about just the extraction itself?
Mm-hmm. So, yeah. I thought that was interesting. At the discussion at the end of the article, they talked about how recent studies, the results were very similar to what – the results they got in this study. And they also used the micro-CT. And they were saying that some previous studies, where the authors had concluded that maybe shaping could cause microcracks, that in those studies, perhaps their results were compromised by their method of sectioning the root and then --
-- and then looking – analyzing them with a stereomicroscope, that this root sectioning approach can be very destructive and can even possibly cause cracks or enlarge cracks that are already there. So, apparently, though, the micro-CT is a very non-invasive procedure.
Yeah. There’s no invasion at all. In fact, I wanna just give a little shout-out to a friend of mine, Gustavo De-Deus. Well, he’s from Rio de Janeiro, this – part of this team is, anyway. And what I liked about him -- I’ve met him, and he’s very smart. The audience out there, you’re going to want to follow – he’s a prolific publisher, and his team. And they’ve done a lot of really relevant [with emphasis] clinical research, because they’re thinking. And he kind of changed the whole paradigm from the old literature. We can almost say 2014 was the dividing line, where they were doing the sectioning before that, and the sectioning procedures were invasive. I mean, they’re cutting the tooth.
But they would do like 10 cross sections per root. He did 35,304, on 24 teeth! So, he was looking at every cross section. And so anyway, he has a private practice in Ipanema! I stayed in a hotel across the street from the Beach Ipanema. It’s quite nice; it’s very romantic. So, Gustavo, boom-bo!
Okay. So, moving on to the next article we’re going to discuss now.
Oh, yeah. We gotta get to that next article.
And it’s by a group of endodontists from Rutgers School of Dental Medicine in New Jersey. The title of this article is “Chamberless Endodontic Access for Treatment of Calcified Anterior Central Incisors” and there’s four authors on this, Paul Falcon, Carla Falcon, Farnoosh Abbasi, and Craig Hirschberg. So, why don’t you give us a little summary about this article?
Well, again, I don’t choose articles based on friendships, but I really do like Craig Hirschberg. He’s at Rutgers, and Phyllis and I’ve talked there at Rutgers to the post-grad students, and so I’ve known him and from the AAE. But their group did a really interesting article. They saw a central incisor, maxillary number 8, and this particular tooth had a Class IV incisal mesial restoration, kind of big. They were a little concerned about it. But mainly, it was a block of dentin. So, there was no observable pulp chamber, and there was no canal certainly in the body. And maybe you could see a wisp of a canal in the apical one-third.
So, after they considered everything, the aesthetics was a big function, the biological width, the reaction of the soft tissue to the tooth, they decided to elevate a flap and go in from a retrograde way. This is where they get the “chamberless” part. And they completely found the canal. They used ultrasonics, the ENAC. I used to have an old ENAC back in the day, in the ‘70s. And they used ultrasonic reverse instrumentation. They used glutaraldehyde. They used CHX. That’s chlorohexidine. So, that was their reagent. So, they were cleaning and shaping, not in the way we’d do it from the incisal, but they were doing it from the retro.
But they were still using instruments, they were using reagents, they dried the canals, they used a Grossman-type sealer. They squirted gutta-percha in, and then, they used pluggers and compacted it, and they backpacked. And then, at the very end, they made a retro prep and put MTA to cork their gutta-percha sealer. So, they have a long-term follow-up, and you’ll talk about that. But anyway, they – it was a clever approach to non-invasively touch the clinical crown and leave the patient’s aesthetics and lip line and all that alone, but yet solving the endodontic component of the problem, through a surgical procedure.
Okay. So, just to be clear, they went in from the apex --
Yes, the apical lesion.
-- because they felt it was not – the canal was too calcified to be able to find it through traditional --
Yeah. They had a whole survey of films that we’re --
-- not showing the audience, but it was – it was your classic block of dentin.
Yeah. It was very calcified. You could see a wisp, though, as I said earlier, in the apical third. So, the thing I wanna say to the audience, and I don’t disagree with this technique, but the canals are almost always present. And even when we say they’re not visible, even with modern-day good, angulated films, my mentor, Al Krakow, at Harvard Forsyth, taught us decades ago, you’re always obligated to make occlusal access. So, a lot of times, you could find them, is my point. But in this paper, the way they presented it, I thought they did a really nice approach, and I have done some like that, myself, because sometimes there’s just – there’s a variety of considerations. This is just talking about mineralization.
Okay. Well, I guess they did show a 52-month recall --
-- in this, where the case is – seems successful. And this person had also had previous endodontics, too. This was --
Oh! Totally forgot! Not only was this thing calcified – oh, wow!
Mistake-o! It had had previous surgery.
And the root had been resected. And in fact, in the axial slice, they could even see the bevel. Because you know how, on a conventional, two-dimensional radiograph, it’s just ognna look like, “Oh, it’s a short root.” And if you look at the adjacent teeth, they’re going, “Short root.” But they could actually not only say – because it could’ve been shortened by resorption or some pathological condition, but they could even see the bevel. So, evidently, the surgeon beveled it down, found a canal, but didn’t put anything in the end, and that was another reason that gave them hope is, they could see the previous surgery. They could see a little wisp of a canal. And so, it was just a leaky system.
Okay. I think that --
-- in the discussion at the end, they – the authors did mention that this chamberless endodontic access that they did may – like could possibly be criticized for maybe leaving bacteria maybe more coronally, that they couldn’t get to, because of the calcification, that they could be criticized for leaving bacteria behind. But yet, they had the successful 52-month recall. So, what do you think about that, like leaving the bacteria behind?
Well, in – I’ll say a couple things. First of all, it’s probably well known internationally, we don’t remove every microorganism from every dentinal tubule. So sure, we could always argue, whether we did it orthograde, conventional, retrograde, we probably are leaving bacteria behind. Even with all the modern adjuncts and disinfection, nobody has ever said, “We perfectly, exquisitely cleaned every time.” That’s why we say “disinfection,” not ‘sterility’. We’d have to put the patient in the autoclave, to approach that.
So, they were concerned about it, because if you looked at the radiographs, their instrumentation didn’t get up into the pulp chamber. But that was a block of dentin. So, I would think you could say this, in closing, for me. You could say that they – the – life’s like a teeter-totter. And if you can go in there and reduce bacterial loads, you’re shifting it for the patient. You’re pushing them towards health. And then, if you didn’t get everything out and you used the sealer, you used warm gutta-percha, and you had an MTA cork, you’ve probably incarcerated any of the remaining bacteria. And if they don’t have substrate, they’re goners. They’re dead [laughs].
Okay. Well, those were some intriguing articles that I particularly liked, because they gave us a little bit of additional insight into topics that we’ve already discussed on our show. So, we will have links, I believe, links and the references on our website, on the Show Notes, for you to be able to find the article. And just thank you, Dad, for telling us about those articles. It was interesting.
Well, it’s nice to know you can clean and shape and be safe, and it’s nice to know that certain endodontic presenting pathologies, there’s clever ways to think about fixing them, fixing the problem, that a lot of dentists aren’t considering.
Yes, and creative alternatives. Thank you.
CLOSE: Case Reports
All right. Let’s talk a little bit about glide path management. We talked about that earlier in the show, but now I thought I’d bring it home with just a case report. And this is – one will be a live patient, and one will be an extracted tooth. We can learn a lot from extracted teeth. I’ve learned so much from teaching over the last 40 years, because I have held thousands and thousands of extracted teeth in my hand, and I have helped me make a mental library.
So, when you look at our friend, the maxillary first molar, in the distal view, you can see we have a DB. You can see we have an MB. And then, look at the MB, we even have an MB root and then we have a bridge, probably some kind of a dentinal bridge, maybe, over to an MB2. And if we look at this a little bit more clearly, the other view, this is the mesial view, this is the distal view, it’s pretty interesting. And so, that’s why we always teach, get three, horizontally angulated films, so we can better appreciate the anatomy. What I’m not showing is the straight-on view.
But for endodontists, oftentimes it’s the off angle that shows us the breadth across this root. I want you to really notice the concavity. Notice the furcal side concavity. Appreciate that the canals are more curved than the roots that hold them. And more curved than the roots that hold them. And then, you can see multiplanar curvature. So, it’s going to be fun. And you’re already starting to think at your preoperative film, “I’m going to isolate the tooth. I’m going to going to make my access. I’m going to get straight-line access to those orifices.” And then, you’re going to grab your 10 file, right, and you’re going to catheterize the canals.
Let’s take a look. So, if we begin to look at this tooth more carefully, what really comes to mind is access, glide path management, we’ve already talked about that. And then, we wanna look at what? What am I doing? All across the world, in my workshops, for decades, I had students do this. Take the tooth, cut the access, then flip the tooth over and cheat, and take a 10 file and stick it into a foramen. Stick it into one of these foramina. Okay? Stick it in there. You will notice that that 10 file, almost every time [with emphasis] in extracted teeth, regardless if it’s from an older patient, a younger patient, it’ll go into the foramen, 2, 3, or 4 millimeters.
That just shows every student in my workshop that the open foramen is present. It’s there! The canal is not calcified, but oftentimes, as we start to work the files coronally through the orifice, “Oh, it’s really calcified down there!” No, it’s typically wide open in the apical thirds. Remember, canals get more restricted in their cross-sectional diameter, as we ascend up towards the pulp chamber. So, this gives every student complete credibility that the foramen is open, the canal is patent. So, I say, okay. Take the 10 file, fine. Take the 10 file, and now that you know you can do this, I want you to carry it right to length. And they can’t.
And oftentimes they can’t, because they don’t appreciate that the 10 file has a 2-percent taper, as we talked about. That means at D16, it’s a 42, and the taper is just too big for the taper of the canal at that moment. Notice the file is completely loose in its terminal extent. So, where is the file binding? The file is binding up in the body. So this should be a clarion cry to all dentists doing endodontics that it’s all about access. It’s not just access in the pulp chamber. It’s access to the apical foramina area, okay? So, if you know that, then we can do something about that. And what we can do is what? We can take our file, and we can slip it into the MB2 orifice. And then, we start that little, familiar wiggle, wiggle, wiggle, and we start drawing the file down.
The file will go a lot of times, a little bit, and then, a lot of colleagues will write an email and say, “It stopped! It just stopped dead! Like it – boom! It like hit concrete!” Well, that’s because the file’s too big for the canal, in its body. So a lot of times, I was abusing this file, towards the end, and you saw it kink, and you saw the file buckle, because it was too big. A lot of you would’ve gone to an 8 or a 6, like Lisette said, but that’s not the prescription. This is the prescription. ProTaper – the ProTaper family of instruments has a Shaper X. It’s the auxiliary shaper. It’s the most used instrument in the world to pre-enlarge canals.
Notice how flexible it is. Notice that I’m brushing away from furcal danger. I’m brushing out of a canal. I’m brushing towards the greater cross-sectional diameter. And I’m only going in about half the active portion. That’s important! Only about half the portion. So, in real time, you just saw that in about 10 seconds, you can pre-enlarge a canal. Now you can take your 10 file, you can stick it in the pre-enlarged canal, effortlessly. You can slide that instrument around curvature, and it will arrive at length. And there it is. So, in just a few moments, we’ve catheterized this canal by one of the most important tricks I’ve been teaching since the ’70s, and that’s pre-enlargement.
I think I was the first one to do that. There’s been the crown down idea. The crown downing is completely different than pre-enlargement. Scianamblo and I were talking about pre-enlargement in ’78, ’79, ’80, because we knew that was the biggest trick, the biggest gift to get to the terminal foramina. Okay. So, that kinda is one little thing that plays back on our Q&A section. Now I’d like to talk about that “Chamberless Access” article! So, we had an article called “Chamberless Access.” Now remember, it was very different. That tooth was calcified! That tooth, you know, was a block of dentin, and weighing risk versus benefit, they thought they would go in and make a surgical procedure.
Well, this has already been accessed. The crown, it’s a porcelain fused to metal crown. It fits very well. It has a post. The biological width is great. The soft tissue response to crown is great. The patient has a high lip line. So, they show the tooth and the gum beyond, but it’s had endodontics, and it’s had even – an endodontist did surgery and sort of shot it in from 50 yards and got it pretty close to the foramen. I would have to say, if it was horseshoes, he gets a point or two. All right. So, let’s take this apart. This is – okay. I’ve been doing this procedure since the ‘70s, and I really liked that article from Rutgers, but I wanted to have another way to explain it.
I thought I’d call it “retrograde obturation of coronally-obstructed canals.” So, chamberless, this has already been accessed. I wanna make that distinction. But the point of that article was that sometimes we would not make a conventional access because we might mutilate the tooth, we might predispose the tooth to weakening and longitudinal fracture. So, in this case, we’ll go very quickly. I’m not trying to teach surgery, but I’m just trying to show you some of those ideas from that article. So, when we get the flaps up, we’ve done an osteotomy. This is a through-and-through lesion. In other words, Ruddle’s going through the facial cortical plate, but the lesion has penetrated the palatal cortical plate.
So now, it’s going to be a through-and-through lesion. And we expect those to heal a little different than a typical, non-invasive lesion that big, right? Okay. So, there’s the amalgam– a little – great shot of it. You can see it perched out there, and you have to think the root resorbed, because nobody would be able to put amalgam in and cantilever it off and have it up in the air like that, unless they were maybe very talented, from another planet. But in this case, the root’s resorbed away, because they haven’t got it sealed. So, what I did is, once I got the amalgam out, I used a 17 Explorer. You can see this gutta-percha in here. It’s kind of disintegrated, but I can jack it up!
And chunk, chunk, chunk, I am lifting this fragmented piece of gutta-percha out of the apical third. And you’re seeing that I’ve got about four shots at it. All right? So, now that we have that up and out, I’ve just skipped to the postop, and you can see the retro. But let’s go back, okay. So, we have a through-and-through lesion. You’re looking at palatal mucosa, red on red ain’t going to work. So, maybe we’ll just give you a little color change here, real quick. But you can see, this is the palatal tissue. That is the palatal tissue. Okay.
So, there’s the retrograde in. You can see a nice, flat bevel, a good repair, and a good seal. But let’s go back. Once we got the flaps up, and we got access to that gutta-percha, and you saw me taking that gutta-percha out, you know, what we did then is, we did something that that “Chamberless” article talked about. And that “Chamberless” article talked about reverse cleaning. So, I didn’t use ultrasonics in that day. I used the apical file holder. Put a file through its collet, break it off, cinch it down, and you can reverse clean these, with a reagent! Okay?
Because we have good control, I had surgical assistants, very good, and they keep that suction – that suction just right there on the beveled root, and they can pull off -- any surplus that wants to go up the hose, they can take it. So, we reverse clean with a reagent, just like they talked about. They used the ultrasonics, we’re doing this manually. And we’re working several millimeters – several millimeters, just like they did, remember? They squirted gutta-percha in? We squirted gutta-percha in. And then, in that day, we were using Super EBA, ethylbenzoic acid. That was what the whole profession worldwide used. That was our first material after amalgam!
So, we graduated from amalgam to Super EBA, to now MTA and different materials, the tricalcium silicates, the repair materials, the putties. But what about that lesion? Is it going to heal? Let’s keep watching. And here we are at 10 years. So, you can see, on a through-and-through lesion, the bone will fill in nicely, around the end of the root and where we’ve done our surgery. But you can see, up in here, that heals in a very characteristic pattern. And typically, that dark radiolucency’s bullseye, and it should be slightly removed from the surgical field so that if the patient goes to another dentist in the future, it won’t be misinterpreted as a current lesion.
So, it’s important to get the history, isn’t it? Okay. So, that’s our show for today. We’ve looked at two cases that kinda play off of our Q&A and then our articles. And I hope you’ve seen another example how to use those ideas, and we’ll see you on the next show. We better see you on the next show!
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