Locating Canals & Ledge Insight Tips for Finding Canals & the Difference Between a Ledge and an Apical Seat

Sometimes we’re confronted with upsets like the hard-to-find canal. This show reviews some strategies for locating calcified, aberrant, or previously missed canals. Additionally, Ruddle gives a very interesting ‘Fresh Perspective’ regarding ledges and apical seats. The show closes with Ruddle presenting 3 intriguing cases featuring locating canals.

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Disclaimer

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: CBD in Dentistry

Lisette

Welcome to The Ruddle Show. I’m Lisette, and this is my dad, Cliff Ruddle. Today on our show, we’re first gonna talk about locating canals, and my dad is gonna give you some tips or strategies on how to locate hard-to-find canals. And then, after that, we’re gonna talk about two different kinds of ledges. And that’s kind of like a little bit of a surprise segment. So, we’ll get to that soon. But first, we’re gonna start off talking a little bit about CBD, because it --

Cliff

Can we do that?

Lisette

-- [laughs] it’s been in the headlines a lot, lately. And for those of you who do not know, CBD stands for cannabidiol, which is from the cannabis sativa plant, but it lacks the THC that gives you the psychoactive effect of marijuana.

So, CBD is completely legal in the – in all of the United States, whereas marijuana is legal in maybe about 11 states. So, CBD has been known for a while now, to – studies have shown that it reduces inflammation. And because of that and combined with its ability to reduce anxiety and also to control pain after a dental procedure, or any type of procedure, it’s now become – being talked about as applications in dentistry, because of those things that it has been studied to show. For example, it can treat inflammation that’s caused by gum disease or that you might have, related to a dental procedure. Patients who have anxiety can maybe use CBD to reduce their anxiety, when they’re at the dental office.

And then, also, it’s been shown to control pain. So, maybe it could take the place of opiates after a dental procedure. So, it’s – it’s showing some promise. And it’s just being studied a lot more.

Cliff

Can you – can I take it like 24 hours before a dental visit and expect some kind of amelioration of my anxiety? Or would I need to load up maybe a week early and have better blood levels?

Lisette

That, I’m not entirely sure. I know some people have taken it orally, like a liquid that they put under their tongue. And it seems to me, from what they describe, that it – it’s something that you take daily, and then, you would maybe notice, over time, a reduction in anxiety. I’m not sure if you take it like an hour or two before the dental office, and then, when you’re there, all of a sudden, you feel no anxiety. I don’t really think you feel that kind of effect from it. I think it’s more, you take it daily, and it helps you, over time.

Cliff

Very good.

Lisette

But I know that there’s a liquid you can put under your tongue. I’ve also heard of people taking it in form of gummies that you eat. And I’ve also heard of creams that you apply topically.

Cliff

Oh, yeah.

Lisette

So, do you have any – have you heard anything about CBD? Do you know anybody who’s taken it?

Cliff

I actually do. I’ll just give three little anecdotal stories. But they’re friends of mine that I have known for quite some time, so I think it’s – their stories – was meritorious [sounds like]. The first dentist, in Southern California, was at the AAE meeting, and he left his home in Southern California with shingles. So, there was a lot of pain. And if you’ve ever had a patient that’s reported shingles, you know that even their clothing touching these open sores is very, very painful.

Lisette

I’ve heard that shingles are extremely painful.

Cliff

So, he was telling some friends at the AAE meeting, in Denver, Colorado, about the dilemma. And they said, ‘Come with me, because just down the street and over, we can get a remedy for you.’ And he said, ‘Well, what is it? Hocus-pocus?’ And he said, ‘You be the judge.’ So, they went to a marijuana shop, and he went, not for the THC and the psychedelic component of it, psycho component. He wanted some relief for shingles.

And so, the lady motioned for a pharmacist to come out of the back, and he looked at it, and he said, ‘I’ll be right back.’ And he came back and said, ‘Just put this cream on, generously slobber [sic] it on. Lather it on’, he said. ‘Lather’. That was quite a word [laughs], ‘lather’. And anyway, it was done, and by the next morning, everybody could only imagine the pain relief, because everywhere this doctor went, he said, ‘Slap my arm!’

Lisette

[Slaps Cliff’s arm]

Cliff

He said, ‘No, no, slap my arm! Slap it everywhere, anywhere! Just slap my arm!’

Lisette

[Slaps Cliff’s arm again] [laughs]

Cliff

And it was a miracle [laughs] for him, because he went from, his clothes couldn’t touch it, to he couldn’t – he could now have his arm slapped. Another story was, a lady flew in, a professor from Beijing, in endodontology was her Department Chair title. And she is known to get migraines, and she gets migraines from time to time, when she flies. And so, she arrived at an international meeting with a roaring headache. And wouldn’t you know that a little bit of the oil was placed on her forehead, and within a half hour her migraine was absolutely gone. And so, she thought it was a miracle, because she’s tried, back home, acupuncture and a lot of more natural remedies, including Western remedies. And nothing was really working with the migraines.

Lisette

I’ve heard other people say that it really has helped them with headaches.

Cliff

My third story is what all of us know. This has been reported for a decade, at least. But terminally ill cancer patients can sometimes have unimaginable pain, and they really do benefit from some of these products that we’re mentioning today.

Lisette

Well, it’s interesting. I guess we’ll see in the future if it – if its role in dentistry increases. It’s – it looks promising. So, with that said, let’s get on with our show.

SEGMENT 1: Identifying Canals

Lisette

Predictable endodontic treatment begins with an effective access cavity that allows the clinician to find all of the canal orifices, so there can be complete treatment of the root-canal system. Missed canals hold pulp tissue and bacteria that will likely compromise treatment outcomes. However, sometimes it can be tricky to find all of the canals.

We’re gonna look at several strategies of finding canals today. But first, can you talk to us a little bit about how a thorough knowledge of root-canal system anatomy can help you locate canals?

Cliff

Yeah. I’ll be happy to. In fact, most important is anatomical familiarity. So, we begin to study – we should begin to study, even as young dental students, the anatomy of the human teeth. And I’m speaking about the human endodontic anatomy. So, one would think, and most important is to be aware of what the anatomy is. Obviously, then, this knowledge begins to be put to forth, if you begin training. So, endless training, endless repetitions and cycles, opening up different teeth, on the bench, extracted teeth, in dental school, and across our careers, help us begin to discover what would be called normal anatomy.

So, if you have familiarity with the anatomy, if you’ve been training, the next thing I’d like to talk about is experience. And you can’t teach that. So, when you have experience, you begin to see different kinds of anatomical situations show up in teeth to visit you daily. Just as a simple example, I’d like to help you start building your mental library of the various tooth groups and the common aberrations we might see. So, central incisors are considered very simple teeth, single rooted, and usually one canal. But you’ll see in just a few minutes, we can have central incisors that have four canals, okay? So, that’s maxillary.

And then, if we look at the mandibular teeth, about 45 or 50 percent, according to the literature, can have 2 systems. So, that’s just a little bit about your maxillary anterior teeth. Maxillary bicuspid teeth are pretty straightforward. Most first bicuspids have two systems, but every now and then, you’ll have an MB and a DB in a maxillary first bicuspid, like a little molar anatomy. Second bi’s, maxillary, typically are fused roots, oftentimes one orifice pretty much in the middle, buccal to lingual. But then, they can also exhibit ribbon-shaped orifices that stretch like a flag flying in the breeze, from the buccal to the lingual. Be aware, in those single, ribbon-shaped orifices, because there’s notoriously deep divisions, and they can end in two or more separate apical portals of exit. I’m almost getting done .

If you get to the mandibular bicuspids, all bets are off. I refer all of my mandibular bicuspids to her, because she’s younger and more athletic, and she can get in there, because these teeth are crazy. They’re notoriously hard, bizarre teeth. You can have mandibular bicuspids that have one orifice and one single canal to length. Simple, simple, simple. But oftentimes the one orifice divides into two or more orifi [sic], and there’s deep divisions, merging systems, and re-bifurcating. So, we have crazy stuff.

In fact, in China, when we talked about that on a previous show, they have – they talk about the C-shaped molar. But they talk about the C-shaped mandibular bicuspid. And I’ve seen a few of ‘em, over here, and they’re really tough. So, little bit about your mandibular bicuspids. Moving back to maxillary molars, we all know about the MB2 now, and now, people are reporting MB3s and 4s. We did this for years. But now, the market is becoming more aware of the anatomy. Microscopes came into play, and we’ll talk about all this stuff behind us. But, anyway, all that’s led to more clinicians’ being more thorough in complete treatment.

So, when we talk about molars, maxillary, they can have MB1s, 2s and 3s. We can have DB1s and 2s. I’ve seen plenty of cases that had two palatals. So, I’ve seen five- and six-canal systems. I don’t know if I should go to the mandibular molars. They also have some challenges. We should probably talk about ‘em. You’ve heard of taurodontia, the deep pulp chambers, where you’re looking down a tunnel, almost to the other side of the earth. And there’s the buccal floor. Course [laughs], vision’s gonna be really important.

So, we have taurodontia. Of course, we’ve talked about radix paramolaris. We’ve talked about radix entomolaris. And those are two situations that have the little extra root. The entomolaris is on the lingual, okay? So, you have your mesiodistal systems, but you have a little tiny root, okay? And it’s on the lingual. That’s the entomolaris, and then, of course, if it’s on the buccal, it’s the paramolaris. C-shaped molars, okay? Just to say a few things. So, C-shaped molars, we all have seen them. Some population groups harbor those anatomical situations more than, say, just regular molar anatomy.

But just in my quick description here, I think – I’m hoping you’re beginning to sense that there’s a lot of variation in what has become known as normal anatomy. So, I think I’d like to bring this home by showing a little movie. But first, I’d like to show the green book. Ah, yes! The little green book on endodontic anatomy. It was my Bible, okay? There’s two of these books in North America, and I have one of ‘em. It was a gift from Joel Dunsky, who was in the Krakow Group, and one of my mentors at Harvard. And he said, ‘Cliff, you deserve this book.’ The other one’s in the Library of Congress.

This book – let me set it up. It was done – the work was done in the early 1900s, and Walter Hess collected 10,000 teeth. They were full-formed, adult teeth. The roots were mature. And that was no small assignment, collecting 10,000 teeth. And he showed us every single tooth, like I just described earlier, and kinda some of the things you might find inside those roots and what they were harboring. So, let’s look a little bit at the little green book. I wished you would’ve all been able to have it, when you were students, because it really influenced my life, and I get kind of amused by all the Johnny-Come-Lately’s that are filling their first lateral canal and getting their first deep division, and they’re really celebrating hard.

But a lot of us had the privilege of seeing the anatomy back in the ‘60s and ‘70s, and it did change how we approached everyday endodontics. Let’s take a look. Okay. So, when you look at this book, it has all the teeth, the centrals, the laterals, the bi’s, the molars, uppers and lowers. And what you can see is, there’s lots of little Vulcanite recovered specimens that reflect Hess’s work. So, this is what Hess did. He cut the clinical crowns off, he had no files, he used no instruments, and he used a mild acid. And what he did is, he digested out all the pulp tissue from the root-canal system. Say ‘system’, don’t say ‘canals’.

Once he had all this tissue eliminated, there was a vacated space. And he used Vulcanite rubber and squirted Vulcanite rubber with a screw gun and delivered Vulcanite rubber into these tough anatomical configurations. He used, then, Aqua Regia, a mild acid, and digested away the cementum and the dentin. And what he had left was one of Hess’s famous Vulcanite recovered specimens. And you can see in between systems, like flags flying in the breeze, sheets of tissue that can harbor bacteria sometimes. These are things where you have to address, when we’re doing endodontic treatment. So, I think this book and its configurations are very, very useful, to begin to plan your treatment, for no surprises.

So, now that we’ve looked at this little book, I’d like to show them a little bit more anatomy. And we can get back to our list, so the colleagues don’t get confused, and they can kinda see where we are.

Lisette

Yeah. Why don’t you tell us, what are the first diagnostic steps, before starting treatment, and the useful technologies that you would need for this?

Cliff

let me go to the other set. All right. Let’s look at some diagnostic steps to help us find mineralized, previously missed, or aberrant canals. If you look at this picture, there’s a little collage of images, and I think you can see immediately, if you look at the maxillary bicuspid, I don’t know that any of us can see any observable canals, even with a good radiographic image. You can see the lesion apically. You can see it quite nicely.

If you look in retrospect, I’ve learned over 40 years, you can oftentimes get better at diagnostics when you look at your post-op films. There’s even a little bit of shadowing, right in here. You wouldn’t normally really notice that, unless you went and saw the post-op film. And then, if you looked at the post-op film, you might go, ‘Aha!’ So, you’d get a little bit better. So, mineralized canals. There’s a lot of examples of previously missed canals you can see in this maxillary first bicuspid. It’s had partial treatment of the palatal root, only.

But you can see, there’s some interesting anatomy. There’s two other roots. In this case, we have a missed root, completely missed. You can see a squig of material coming off the body, trying to get into that canal. So, that’s interesting. All these were re-treated successfully. And then, of course, this clinician, when access didn’t work, then went in and referred to an endodontist who did surgery, trying to cork that system. But you can see, there’s a lateral root lesion. And so, there’s examples of things that we need good diagnostic x-rays, so we can see.

So, let’s take a look. If you look here, a colleague has gone into a tooth, made an access, but couldn’t get really any further than about right here. So, what I had to understand is, canals divide. So, when canals go up, and they’re easy to observe all the way to the end, probably one system. But if you see a canal that goes up and disappears, it’s a canal that probably divides. And if you look at the post-op film, if I can go back, and we look at the post-op film, you can see that the explanation for why the initial operator couldn’t get the length was, the canal divided. And then, off that more buccal branch, you can see all these nail heads, of multiple apical portals of exit.

So, good radiographs are a good idea for the colleague to be insisting on, and have the staff trained up, so they can take really good, reproducible films. CBCT has been a huge adjunct to all diagnostic procedures, especially in endo. And you can see, in this sagittal view, we have a lateral canal coming out facially. There’s a loss of cortical plate, and we have debris disseminating out, causing a lesion of endodontic origin. So, CBCT is a critical part of the diagnostic technologies that we’d be utilizing to first initiate our ideas, before we touch the tooth, before we start to touch the tooth.

So, in other words, if you look at this second molar – or, first molar, I take a lot of crowns off, because it helps me better visualize the underlying tooth structure. I have better orientation. And you can see, when you get in here, the colleague is usually trying to pick along in this imaginary little groove. They’re hoping to find a canal, but this is still shelf. This is still roof. This is still a lip or a tongue of dentin. You can see, it’s been removed over here. Probably everybody watching this would say, ‘Well, I can do that.’

Well, if you can do that, we can just use different ideas to peel off that lip, and there is the hidden orifice that can be pre-enlarged, so we can get to length. Crown’s provisionalized. The root-canal treatment’s done. You can see the separate portals of exit for the MB2, and the MB1 is bifid. It really helps to see. Like in this case, you can see that the roof, the pulpal roof and the floor, are almost contiguous. You can see that we have a little bit of concavity. You can see these two lines, in here. That’s the concavity. So, we start our access, surgical length first, kick the head of the handpiece further away from the occlusal table, so we have a good line of vision, right along that instrument, and we can actually watch the burr work.

I’m showing you an Explorer, the tip of the proverbial iceberg. This is a big dentinal stone. It’s occupying the whole pulpal floor. Here we are, using ultrasound, kicking it out. You can see how thick it is. It even has projections off the stone that went down into the various orifi. So, we’re talking about how ultrasound can help us kick out stones, trough for extra canals, like troughing along the inner connector. If you trough along between the MB and the DB, MB, ML, MB, ML, back and forth, pretty soon, you can use the air, in other words, the Stropko is the device I’m showing. The triplex syringe comes like this, in standard.

But we would take this and kick it out, get rid of it, and put the Stropko in. It can receive micro cannula that can be used to blow precise columnated air into an area so we can keep the area clear, so our vision is continuous. So, this is a big idea. And when you finish troughing, you can see a file has starred in the mid-mesial. Be aware that there’s a furcal side cavity. So, we have to shape away from furcal danger. And you can see, when we start to do that, then we can find all three systems, and it gives us a chance to do complete treatment. Okay? Complete treatment!

The post-op’s fun. If you look at any particular cross-section, the mid-mesial is always a more conserving preparation, always, because remember, we showed that fluting, that external concavity on the furcal side. Mandibular incisors oftentimes have two systems. You can see to look in. The air is usually to make a rounder foramen, but clinicians that know the dimensions of these teeth, buccal, lingual, they’re broad roots, right? Broad roots, narrow mesial distal, broad facial lingual, while the extra orifice, the second system, the lingual one, is there. So, drag those accesses a little bit to the lingual, at the expense of the cingulum. And then, you’ll be able to have confidence in your endodontics, when all this restorative work is gonna be done, coronally.

Well, who said central incisors have one, single canal? Right? Well, they do, but oftentimes they can have two. I’ve seen cases like this one. My friend, Francesco Mangani, in Rome, we published this case in the “Journal of Endodontics”, in 1994. It’s a very particular tooth. It’s a dens in dente, and we talked a little bit about a tooth within a tooth. But if you begin to look at this, you can see, there’s resorption, certainly. You can see multiple canals and big lesion, apically. So, there’s two of ‘em packed off and two more systems have been found, at the midline. And if you look at the photograph, you can see the two packed ones.

You can see the two – oh, I’m being alerted. I have an emergency. Just – I’ll take it in just a minute. Don’t worry. They’re in pain, but I’m coming! [emphatically] All right? So, we have two systems here, on the midline side, and you can see the two files. And finally, if you kick that out and bring the post-op in, notice the lesion? Lesion’s very, very big. It’s a big wrap-around lesion. Already on second visit, we can see ossification. Already, we’re seeing some repair up in here, and then, this is only about six weeks later, where we packed it. And then, they got the restorative on the lingual. So, dens in dente.

Well, the other thing that would be helpful, besides the films and the cone beam, would be to have vision. And vision can take place in a lot of different ways. And certainly, some of you are already enrolled and wearing magnification glasses. You have your headlamp built in. These sit on your nose, and they can let you see a lot of dentistry. You only know what you see, and you only see what you know. Transillumination’s important, because we take a straight 1 fiberoptic, different ones, different configurations, and we can put it either above the rubber dam or below the rubber dam. We can turn the microscope light off, or the overhead light, and then, we can transilluminate, buccal to lingual, and identify pulpal floor anatomy, like in this example.

So, you can see the palatal would be over here. This’d be the DB. We’re not really trying to feature it, but you can see the MB1 and its related groove, trailing off towards the center of the tooth. So, transillumination, then, is a big deal. So, to summarize, radiographs, CBCT, and vision. Vision equals lighting plus magnification.

Lisette

Well, okay. So, say you just opened up the tooth and are beginning to find the canal orifices. What is your first line of offense?

Cliff

Well, if it’s football, don’t forget to protect the quarterback.

Lisette

[laughs]

Cliff

[laughs] My first line of offense [laughs], on the life of endodontics, in the game we play there, would be, basically, to have a few burrs that you really like. You don’t need very many. I like football diamonds. They’re very useful, and they can help us get into teeth. Because it’s football shaped, the tip stays more centered, and you’re cutting more with the belly, which means you can take the axial walls laterally but not dig in and ledge deep. So, you have your favorite burrs. But my favorite burr of all is the one that does the finishing. In any access, all the internal axial walls should be, repeat after me, at home – I can hear you! ‘Flared --

Lisette

Flared.

Cliff

-- flattened --

Lisette

Flattened [laughs].

Cliff

-- finished!’

Lisette

Finished.

Cliff

I heard, ‘Flared, flattened, and finished’. So, these axial walls should be flared, flattened, and finished. Notice how all vision is right on the pulpal floor. The size of your access cavity isn’t a Ruddle thing. It’s not any of your gurus at home. It’s anatomically driven. You saw the Hess work. So, the pulpal floor is smallest on the floor, where the orifices are, and all the axial walls diverge a little bit out towards the coronal, so we can visualize. And you can see stones in here, stones, stones, stones. This tooth was called ‘Stony’. That was a joke. Okay.

Lisette

[laughs]

Cliff

So, that’s my favorite thing, straight-line access, and just get it. Don’t hope you have it. That’s a religious concept. Hope is really good in church, but when you’re in the operatory, just plan to be successful. And then, of course, your Explorer, the cheapest thing in your operatory is a magnificent way to punch through a little lip or overlying translucent dentin shelf. And you can pop into oftentimes orifices, and that’s way safer than drilling or trying to look around the bulky head of your handpiece so you can see. So, I will bend over the tip of an Explorer and go through Explorers just like many of you go through your 10 files.

Lisette

Okay. So, say you have a really good access. You believe it’s a good access. And you’ve poked around a lot, but you still are having trouble finding canals. And you suspect there’s another one, based on radiographs. So, then, what are the other – I see that would – we have lots of strategies, here. So, why don’t you go and take us through some of these strategies.

Cliff

Yeah. I’ll just say a sentence or two. You and I’ve written a few paragraphs about each one of those. So, in the economy of time, here, we’ll just say a word or two. But certainly, perio-probing comes to mind. We’ll come back and look at the list over here. You have it on the other camera. But let’s look at the perio-probing. So, oftentimes, when you’ve cut an access, we’re done now, but the point is, if you step your perio-probe circumferentially around the tooth, you can look through your access cavity when it’s live and you’re doing it, and you can look at the distance from the Cavosurface internally to where the MB might be or the ML. And it has to do with the rules of symmetry.

So, perio-probing gives you the emergence profile of how the root begins to move down underneath the free gingival margin. And when you start to have – you can even feel inclination. So, inclination and orientation are huge. Of course, get rid of the crown. If you’re really struggling – we go through crowns to save people money. That’s a noble thing. But if it’s going to compromise your result, then consider just removing the casting. There’s several ideas I like. I’ve talked about ‘em in many different venues, but this is called the metal lift, and there’s a special kit. And it helps you make a hole, one millimeter – one millimeter. That’s pretty conservative.

And oftentimes you need to explain to your patient -- be very careful explaining, because if porcelain flexes 1/10,000th of an inch, it will shear off and fracture. So, remember, you’re doing a benevolent procedure. You’re trying to save a casting. But at the end of the day, if you can get the casting off and be successful endodontically, crowns can be remade, or even the same crown can be provisionalized.

Lisette

I have a quick question on that.

Cliff

Yeah.

Lisette

So, say you damaged the restorative slightly. Can it be repaired?

Cliff

Oftentimes – I’ve worked with many dentists in Santa Barbara, where we – if we have broken porcelain, which hasn’t – it’s been less than five percent on porcelain fused to metal, but if we did, they can go to the laboratory, and they can oftentimes repair that. Yeah.

Lisette

Okay.

Cliff

So, the idea, again, getting the crown off. You can see the underlying prepared tooth. You can see that there’s a post in here. You’re already starting to plan ahead, begin to visualize, think, plan, and execute. All the stuff helps. So, get castings off, so your orientation is improved. Remember, castings can be placed in any manner the dentist deems necessary to facilitate ethology [sounds like] or occlusion. So, oftentimes the crown could be on at a little different or a lot different orientation than the underlying abutment.

You saw this case earlier, but color is huge. And color – the lighter areas, these lighter areas in here, of course, that’s – those are danger areas. But look at the dark area. It has to do, in this instance, if you think about morphology in tooth development, it’s the three lobes of a maxillary tooth coming together, and it fuses. And you get these dark lines. And these are our anatomical roadmaps. This is the roadmap from Santa Barbara, which is about right in here, and it takes us right over to downtown Los Angeles. And along the way, we might see a groove, and we might find Camarillo, right in here. Ooh, isn’t that interesting!

Look at this dark gold. So, that’ll take you right over into the DB. So, color is good. What is the point? Keep your burrs off the pulpal floor, because you’re destroying color, and color is a roadmap. Ultrasonics, I’ve been involved in inventing tips, 25 years ago. Everybody’s making tips, but the main thing about ultrasound is, you don’t have a big, bulky head of a high-speed handpiece, to try to see around. You can look right down a contour angle tip. You have a great line of sight, and you can watch these tips work. These tips are about 15 times smaller than your smallest available round burrs on the market.

So, ultrasound is just to do a little job. It’s a little task. We usually work at very low powers, sometimes around one, two, max three, so we don’t needlessly break these tips. So, we have coated, double-diamond composite coatings. We have NiTi tips. These are titanium tips. Don’t get confused with NiTi. NiTi is the files. The titanium gives you a longer tip, a thinner tip, and these tips are profoundly thinner in their cross-sectional diameter than you can do with stainless steel and a double-diamond composite coating. So, we can use a round burr. This is a 0.5, half-millimeter round burr diamond. You can drag that ball back and forth and back and forth and back and forth, and there it is. There’s that little orifice, and that is payday.

We talked about symmetry and everything, but you can see, this is kind of an unusual anterior abutment. It’s carrying a four-unit bridge, boom, boom, boom, boom, and you see a little something, right here. That’s the pulp chamber. But if you look carefully, you can begin to map a DB root. You can map an MB root. And I’m pretty close to this screen, but I think I can see maybe the palatal root, right in there, DB right in here, and here’s the MB, right in here. So, obviously, different views, CBCT, help us to completely understand how to do this. The bridge came off.

But look at the rules of symmetry. Here’s the file going into the MB, over here. Here’s the file coming, crossing it, over into the DB. So, everything is centered. If you find a canal skewed off in one direction, then you have to know for sure, there’s something over that’s complementary on the other side. So, simple kinds of endodontics, provisionalized bridge, the tree in the three systems. It’s like a little mini molar. Bubbles, champagne, when you have sodium hypochlorite, it disassociates into the OCL ion, the chlorine oxygen ion. And oxygen will liberate as it reacts with tissue that was never located in that MB2 canal. The solution, the reagent reacts to the tissue, and it liberates oxygen.

And so, you can just see these bubbles emanating up towards the Cavosurface, and that’s another indicator. So, we talk about the Champagne or the Bubble Test.

Lisette

That’s actually called Champagne Test, just because of the bubbles? It has nothing to do with champagne?

Cliff

Well, I usually drink champagne, after I --

Lisette

[laughs]

Cliff

-- find the orifice. But no, it’s just because of the bubbles and when you open up champagne for New Year’s Eve or something, you know, you get all that effervescence and bubbling. It’s a magical time, isn’t it? All right. So, finally, we’re almost done with our big list, to keep you oriented. But oftentimes if you go into a necrotic tooth, okay – so, it doesn’t bleed. It’s necrotic. As you use your ultrasonic instruments, and you sweep them back and forth, the biproduct of cutting is dust. And dust goes into these grooves. And so, it won’t look white, literally.

And you can just kinda watch the white, and as you keep working, you can keep following the White-Line Test, and it’ll lead us finally to where we can get into the MB2. We even have to modify what surgical length diamonds – our mesial marginal ridge, you gotta take that wall back, at the expense of the precious marginal ridge. But that’s how you find MB2s. White Line. Well, obviously, if you open up into a tooth, and it’s vital, and it bleeds, and blood is emanating out of the orifices, as you start to control the bleeding in your more significant canals, the ones you always find, you can sometimes notice residual bleeding, coming out of grooves.

So, if it was necrotic and you started to use ultrasound, it’d be a white line. But blood can absolutely emanate, and it’s a little bead, a little drop of blood. I was pretty concerned about this one, because I’m putting a file in that eventually went in right here, and that looked like, to me, I’m out here in the middle of the pulpal floor. But this was an MB1, MB2, DB1, DB2, and a palatal. It was a five-canaler.

Well, finally, we’ve gone through 14 ideas. I didn’t even talk about all of them, but I hope you’ve learned something. The tips are there for you. We don’t use these tips all the time, on each case. A lot of you are using these tips, and you’re not really thinking about ‘em, but there’s a lot of things we can reach down into our bag of tricks, to help us find missed canals, aberrant canals, and mineralized or calcified canals. And of course, I’ve trained thousands and thousands of dentists around the world. Here’s a Japanese guy, Hideki. You know, Hideki likes to come over from Japan. He’s a junkie, a course junkie, and we have a lot of fun.

And learning should be done in an environment that has good technology. You should have access to the latest and greatest. It should be done in a way that is inspirational and actually can be measurable, because if you can’t measure what you’re teaching, then how do you know you’re teaching anything that’s even worthwhile? So, Hideki goes back home, then he sends me lots of cases, showing me what he learned. So, I know the ideas we talked about today are transferrable, and Hideki’s havin’ fun, and I’m havin’ fun. And endodontics should be a lot of fun.

Well, I guess I have a couple more things to say.

Lisette

[laughs]

Cliff

So, in essence, I would close by saying that whether you’re accessing a maxillary tooth or a mandibular tooth, whether you’re accessing an anterior versus a posterior, a single-rooted versus a multi-rooted, whether you’re performing initial treatment or re-treatment procedures, whether you’re going through a single restorative [laughs] or whether you’re going through a multiple-unit bridge, if you can see it, you can do it.

Lisette

It sounds like vision is really crucial [laughs].

Cliff

Vision’s absolutely critical, and out of all the technology, still, well-angulated periapical films and your CBCT are allowing you, before you’ve ever sat down, to be successful or make a mistake, it allows you a treatment plan for no surprises and gives you a lot of confidence, how to skew your access in, to take advantage of where they really are versus some restorative that might be throwing off your landmarks.

Lisette

What do you think about, if you’re trying all of these things, and you’re still having problems? Then, maybe it’s best to just reschedule the patient and try on another day?

Cliff

You know, what you’ve said is huge, and I hope everybody really heard it. So, would you repeat it?

Lisette

If you’re having a lot of difficulty, maybe think of rescheduling. I know, as a patient, I would be like, ‘Oh, gosh! Really? I have to come back? You can’t do it?’ But I know that a lot of times, when I’m doing something, and I’m stuck, and I walk away and come back, immediately the answer comes to me.

Cliff

So, my mentor, Al Krakow, was a genius of a man, great storyteller, and so good at endodontics. He told us, when we were kids at Harvard, way back in the mid-‘70s, he said, ‘You know something? Sometimes you just have to close the case.’ And he said, ‘The next time they come in, a week later, a month later’, he said, ‘It’s so embarrassing.’ Because, he said, ‘It’s right there! You can’t believe you were looking and looking.’ And your whole point I wanna play off of is, if you don’t’ know where you are, and you’ve lost your orientation, sometimes we wanna be successful, and we’ll keep going. And sometimes we’re off track, and now, we might perforate. And that’s another whole problem that really lowers the prognosis of the tooth.

So, yes. Just reschedule, fresh day, different way of seeing things, different references. The world you see, the world that is, they’re not always the same. I guess I’d like to tell the group a little story about – it’s really a famous study from Johns Hopkins University. So, Johns Hopkins University looked at kids in the greater East Coast area, and they found that there were, of course, the learners, and then, there were the kids that had what was perceived to be learning disorders or behavioral disorders. So, they thought that was the problem.

Johns Hopkins found out that one-third of all school-aged children, second and third graders, were myopic. They were myopic, which means they could not see far. So, they weren’t seeing the board. They weren’t able to fathom stuff. So, they just weren’t doing very well. So, one-third were myopic. Second and third graders, one-third. One-third of that one-third were fitted for glasses, and all of a sudden, they came to school on a regular basis, their classroom grades went up, and all of a sudden, they did better on their SAT scores. What’s the whole point of this discussion? Just like the visually impaired students, the visually impaired dentist, if they can see, they can do it.

Lisette

And I guess if you’re still having problems, after everything, maybe you don’t have the kind of technology you need in your office, maybe you should just consider a referral?

Cliff

I think we could close on that. Because, you know, I like heroes. We all love how our heroes in sports and runners and Black Belters and baseball players and championship teams, we love heroes. I mean, our society loves heroes. Can’t get enough heroes. But remember, the hero thing to do is, it’s not about you. It’s about your patient. So, refer the patient, and that’s the greatest thing you could ever do for that patient. And then, as a little bit of a joke [laughs], I’ll say in closing, there’s an old adage of, if more than one person’s responsible for miscalculation, no one’s at fault. [laughs]

Lisette

[laughs] Great. Thanks.

Cliff

All right, thank you.

SEGMENT 2: Fresh Perspective – Ledge/Apical Seat

Lisette

Okay. So, the purpose of this segment that we call “Fresh Perspective”, is to get you to think of something in a different way than you maybe have up until now. We often accept ideas without really questioning them. So, this segment is designed to get you to think outside the box, break down paradigms, that kind of thing. Today, my dad is gonna talk to you about how an accidental ledge compares to the intentional creation of an apical seat.

Cliff

Okay. One of my pet peeves. If you look back over traditional education, over the last 50 years, in North America, let’s say, there was great fear, yes, anticipation of inadvertently moving filling materials beyond the tooth, out into the periodontal ligament [sounds like] space. There was so much concern with it that many techniques [laughs] arose to try to prevent that from happening. As an example, if you look right here, you can see that there is a shelf that is intended to hold the gutta-percha, inside the root. In fact, Marshall, at the Oregon Health Science Center, many years ago, taught purposely creating dental chips and placing dentinal mud in the apical portion, because there, again, was fear of sealer or obturation materials in general getting beyond the terminus.

So, different techniques arose, but the biggest one was the Washington Monument. And you’re looking right at it. So, the idea was maybe stay back a millimeter or two, and then, take your bigger hand files and intentionally carve out a Washington Monument, what would be none other than a ledge. So, usually, as these big files were grinding towards length, mud was produced. You begin to back the larger files out of the root-canal system, and we were now losing the vertical extent of treatment. So, that was another problem.

And when we wanted to make the adjustment, clinically, it was really hard to make these adjustments, because you oftentimes had a block canal and a ledge canal, and ledge management is a whole thing. If we look at this other drawing, the whole world doesn’t like that. I’ve, in fact, written many chapters in international textbooks about non-surgical re-treatment. And one of the categories we’ve focused on is blocks and ledge management. So, in another show, we’ll be talking exactly how to prevent them and how to manage them. But right now, Lisette kinda brought to your attention paradigms and belief systems. So, isn’t it kind of odd that everybody condemned the ledge in the outer curve?

That ledge was not only a nuisance, because sometimes, you know, a nuisance ledge can be buffed out with larger files, making a smooth, tapering pathway to length. But oftentimes when ledges got to be what we identify in the textbooks as Class II ledges, then, you’re not gonna ever remove the ledge. It’ll never get buffed out. In fact, to do so would be to probably materially weaken the tooth. So, I just wanted you to look at two ledges. One, we have said, for historical reasons, round of applause [claps], isn’t that great. And then, we have another one that we all go, ‘Oh, oh, it’s a ledge! Don’t make a ledge! That’s terrible! That’s iatrogenic!’

Well, both, in my mind, are iatrogenic. In our life, we’re off course, most of the time. So, life’s about making those little adjustments that guide each case to a successful conclusion. The adjustment would be a smooth-flowing prep, from the terminus, up to the orifice. Okay?

Lisette

From my perspective, the layman’s perspective, this actually looks worse, over here, because it looks like this one has two ledges [laughs]. So --

Cliff

[laughs] Oh, yeah. You’re right. We can brag, over here, and pound our chest. We made a circumferential [enunciated distinctly] ledge.

Lisette

-- [laughs] oh, yeah. Just from the picture, though, it looks [laughs] like two ledges, to me.

Cliff

Yeah.

Lisette

Okay. Well, that’s very interesting. Thanks for enlightening us.

CLOSE: 3 Ruddle Cases Featuring Locating Canals

Lisette

So, that’s it for our show for today. Hopefully you learned a little something about locating canals and have a different perspective on ledges. To close, I would like to have my dad present to us three different cases, featuring locating canals.

Cliff

Okay. You got it. And specifically, when we talk about locating canals, I’m gonna pound on this, there’s kinda like three instances we all think of. There’s the mineralized one. I mentioned this earlier, the calcified one. There’s the previously missed one, and then, there is the aberrant canal. Let’s look. So, in the mesial view, radiographically, you can see, in the first bicuspid, you can see the buccal root has moved distal. So, this is the rules of symmetry. The distance from the gutta-percha to the Cavosurface is not the same as the distance from here to here.

So, when we have alack of symmetry, we can be certain, in the mesial view, the buccal treated canal moves distal, and we have a missed lingual canal. So, we know that, before we even start. So, did I mention they were having a little bit of discomfort? Did I mention there was a lot of swelling? It looks like the tissue might even be [makes face with tongue in right cheek] like that? Okay. So, off with the crown. You can see the post is out. There’s the buccal. But again, the rules of symmetry, the distance here and the distance from, I’m off the screen, but it’s – [electronic tone] whoa, that’s good!

I made lots of noises and sounds. But, anyway, I’m not sure how we just do that. We’ll try that one. Nope, that didn’t work. So, we’ll cancel it. Sure, you wanna – to exit the TV system?

Lisette

Cancel. Okay. There.

Cliff

[Electronic tones] Okay. So, we’re back in. So, Ruddle had a missed canal. I just overcame adversity, and I’m back in the game, and I’m oriented. And I know I have to drag my access to the lingual. When I do that, you can begin to see, everything looks right. The buccal’s about equal distance from the buccal surface, the lingual from the lingual surface. You can see the post-op. This was a – really an over-instrumented area, way big. It kinda reminds me of earlier in the show, we talked about [laughs] the ledge.

Lisette

Yeah. I saw that. I thought, is that an apical seat?

Cliff

So, that was that. That was their training. Here’s a Ruddle shape. It’s more uniform. But we got the lateral canal. And then, you can see, in about 10 years, the bone’s coming in beautifully, and the predictability of endodontics is inevitable. The capacity hill is there, when we remove and eliminate the contents of the root-canal system. So, that’s an example of a previously missed canal. And then, this would be an example of an aberrant canal. So, it looks pretty good to most people. I think this is short. I don’t think it’s short. It is short. I think these are short, but I’m also looking at the distance across this root. It’s enormous.

Let’s disassemble. Off with the bridge. There’s the core. There’s the three post heads. Out with the core. Now, we’re done to the pulpal floor, just progressive disassembly. But when you look at all this, you might ask yourself, ‘How did all this tooth structure grow?’ Well, it takes pulp to elaborate dentin. So, immediately you’re gonna think about getting your posts out and your cement and all that stuff. But we’re gonna drag our access over, and we’re gonna focus right in here. And sure enough, you can tell this is an old case, look at that unidirectional stop. Today’s stops are appropriately round, but in this world, this is pointed. It was an orientational stop.

This canal is curving distal buccal, and you can see the other three systems have been recleaned. There’s the pack. That’s an aberrant canal. Nobody is thinking about looking way over to the lingual. I don’t even know what to call that. This is the MB, the ML, and I call that the ML2. And the post-op film is fun. The bridge is back on. You can see, we’ve extended treatment vertically, played the curve. Oh, don’t you like to play the curves? All right, play the curves.

And the last case really is the one you saw at the first part of the presentation, where you really can’t see much of anything. You see discernible radiographic evidence of canals in the other more adjacent tooth, more anterior tooth. But in the bicuspid, it looks like a block again. Remember I told you to focus a little bit right in here? I said, in retrospect, you can sometimes look at your post-op film, go back and look at your pre-op. And you’ll go, ‘Whoa! There was a subtle, early lesion, incipient.’ So, you pack it off. We haven’t deviated. We have good straight-line access in there, through the casting. You can see the evidence of the lateral canal. You have a little crossing over, a little, you know, one branch crossing in front of the other branch.

So, that’s fun for me. Anyway, that’s a mineralized canal. And that was before CBCT. So, what I wanna say is, Lisette mentioned about maybe another day, fresh look. Maybe think about Hess’s work, maybe the 14 ideas . You start to put all these together, and you can do a lot of stuff. Back to this, you can now see, with treatment, you can see that lateral canal was going right out to where there was, in fact, a lesion of endodontic origin. So, I think, for me, we could show lots and lots of cases, but I think three final cases, playing back off of locating canals, aberrant, previously missed, calcified, I think we’ve given them a little glimpse of that.

So, I should hustle, probably, back to the desk [Background music] and come around, and give my wing mate a little hug.

Lisette

So, those are some great examples, and I think we all learned a lot today. See you next time, on The Ruddle Show. [Background music]

END

Watch Season 4

55:16

s04 e01

Tough Questions & SINE Tips

Who Pays for Treatment if it Fails and Access Refinement

54:02

s04 e02

Endodontic Diagnosis

Assessing Case Difficulty & Clinical Findings

50:12

s04 e03

CBCT & Incorporating New Technology

Zoom with Prof. Shanon Patel and Q&A

56:53

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Best Sealer & Best Dental Team

Kerr Pulp Canal Sealer EWT & Hiring Staff

49:44

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Ideation & The COVID Era

Zoom with Dr. Gary Glassman and Post-Interview Discussion

59:00

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53:40

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Tough Questions & Choices

The Appropriate Canal Shape & Treatment Options

53:15

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Q&A and Recently Published Articles

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46:19

s04 e09

Hot Topic with Dr. Gordon Christensen

Dr. Christensen Presents the Latest in Glass Ionomers

00:52

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01:43

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48:42

s03 e01

Treatment Rationale & Letters of Recommendation

Review of Why Pulps Break Down & Getting a Helpful LOR

52:27

s03 e02

Profiles in Dentistry & Gutta Percha Removal

A Closer Look at Dr. Rik van Mill & How to Remove Gutta Percha

48:10

s03 e03

Artificial Intelligence & Endo Questions

AI in Dentistry and Some Trending Questions

58:54

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How to Stay Safe & Where to Live

A New Microscope Shield & Choosing a Dental School/Practice Location

48:20

s03 e05

3D Disinfection

Laser Disinfection and Ruddle Q&A

48:28

s03 e06

Andreasen Tribute & Krakow Study

Endodontic Trauma Case Studies & the Cost of Rescheduling

55:22

s03 e07

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1:05:24

s03 e08

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Carrier-Based Obturation & John West Article

55:48

s03 e09

Retreatment Fees & the FRS

How to Assess the Retreatment Fee & the File Removal System

1:00:42

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Research Methodology and Q&A

Important Research Considerations and ProTaper Q&A

00:44

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Watch Season 2

51:43

s02 e01

ENDO 101: WAVEONE GOLD

Product History, Description & Technique

51:42

s02 e02

Interview with Dr. Terry Pannkuk

Dr. Pannkuk Discusses Trends in Endodontic Education

58:21

s02 e03

3D Disinfection

GentleWave Update and Intracanal Reagents

1:04:53

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GPM & Local Dental Reps

Glide Path Management & Best Utilizing Dental Reps

1:01:10

s02 e05

3D Disinfection & Fresh Perspective on MIE

Ultrasonic vs. Sonic Disinfection Methods and MIE Insight

53:03

s02 e06

The ProTaper Story - Part 1

ProTaper’s 20+ Year Journey as Told by the Creators, the 3 Amigos

57:53

s02 e07

The ProTaper Story - Part 2

ProTaper’s 20+ Year Journey as Told by the Creators, the 3 Amigos

1:06:40

s02 e08

Interview with Dr. Cherilyn Sheets

Getting to Know this Top Clinician, Educator & Researcher

1:13:21

s02 e09

Broken Instrument Removal

Why Files Break & the Ultrasonic Removal Option

49:01

s02 e10

3D Obturation & Technique Tips

Warm Vertical Condensation Technique & Some Helpful Pointers

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36:27

special e02

SPECIAL REPORT: COVID-19

The Way Forward

51:17

special e01

SPECIAL REPORT: COVID-19

How the International Dental Community Is Handling the Pandemic

Watch Season 1

45:30

s01 e01

An Interview with Cliff Ruddle

The Journey to Becoming “Cliff”

52:35

s01 e02

Microcracks & the Inventor's Journey

Ruddle Insights into Two Key Topics

47:17

s01 e03

Around the World Perspective

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40:29

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What is the Appropriate Access Size?

52:13

s01 e05

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Tips for Finding Canals & the Difference Between a Ledge and an Apical Seat

53:14

s01 e06

Censorship in Dentistry

Censorship in Dentistry and Overcooked Files

50:22

s01 e07

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Vital Pulp Testing & Choosing Between an Implant or Root Canal

55:30

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49:36

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58:05

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Happy New Year

2020

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Disclaimer

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