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…This one came right out of a Gorilla. I didn’t even want to do this case. I said is Buchanan in town? Is Terry Pannkuk in town? Who’s in town that wants to do this case?...

Welcome to The Ruddle Show. I’m Lisette and this is my dad, Cliff Ruddle.

How you doing today?

Good, what about you?

Great because I’m sitting right beside you. That’s awesome! And I hope you’re out there doing just as well as we are here.

Okay. We wanted to start off our show today giving you another job idea. You might remember the Hockey Team Dentist idea we gave you a few seasons back. Well, maybe you’re tired of the routine of practicing regular dentistry day after day in your quiet office. Maybe you’re actually interested in crime stories; in solving mysteries. So maybe the perfect job for you is a forensic dentist, or to be more precise, a forensic odontologist.

So the field is primarily concerned with the use of teeth and oral structures for identification in a legal context. And you actually know someone who did this, correct?

Yeah. I haven’t spoken to my pal, Joe Cwikla – how about that for a name? Gees, it’s got Cs and Ws and all. But Joe practices in Indialantic, in Florida, and he came out and took all my courses, all four of them over about a two year period with his friends. And I never learned this until I went to see him. So I was lecturing in Florida and he wanted Phyllis and I to stay at their home. And we normally stay in hotels so we’re not disruptive, but we acquiesced and they were delightful people, him and his wife at that time. And we were having dinner and it came up that he was a forensic odontologist, and I had never met one. In fact I only knew about them when I read the newspaper and stories and stuff about disasters, and you understand they do this stuff, but here he was right in front of me.

Joe is a man of few words; he doesn’t really talk a lot about anything. And what I could get out of him was he’s called upon from time to time to visit usually disaster sites where there’s been a loss of life, more than one, like a plane or something. He didn’t say very much, but what I heard is it’s very tough work emotionally, but very quickly you elevate above the chaos and the disaster and the grimness of it all, and you begin to – your training kicks in. And your training is you’ve been around teeth your whole life, so you start looking at the odontogenic aspects of this mouth. And you are rising and ascending above the work, and you do this because you know it’s going to bring closure to the families. And so he always thought that was a really important thing; to be able to lay someone to rest and you know what happened.

Yeah, I would think so. So is it really the case that teeth are pretty much as unique as fingerprints?

Oh yeah. They’re the last to decompose of the human body; much, much harder than bone, so the enamel and dentin in that order of hardness to less hardness. So they’re always hanging around. So they’re very good for identification because they each have their own morphology – that’s size and shape. There could be a rotation, tipping, angulation; there can be restoratives; there can be caries, pathologies in the teeth. What else? We have discolored teeth, missing teeth; and all this together, of course, you can match with somebody’s dental records and it’s very, very – it’s as good as DNA. In fact, teeth actually have DNA, and that’s another level that I won’t get into, but you can get DNA from teeth. And female versus male because of tooth X&Y.

Well not only can you identify an individual from dental records, but bite marks are also unique and can be used to identify the perpetrator of a crime. Now I did read an article that said bite mark evidence can be questionable; mostly because the process, procedure and methodology for comparison are not standardized, and the competence of the examiner varies quite a bit as well. But there have been cases in history where individuals have been convicted based on bite marks evidence, but then later exonerated based on DNA. That said, there is an ongoing effort in the field towards standardization, and also developing proficiency tests to become a certified forensic odontologist.

Now I just want to add that we had already chosen to do this segment, and then I saw the headline that they are actually requesting forensic odontologists to come to Maui to help identify people there. But maybe you can give us some other famous examples from history where dental forensics came into play.

Ted Bundy comes to mind. There were several things that in concert came together to form a 100% guilt. But the bite mark on the butt, which I guess was one of his MOs, that turned out to be one of the collaborative things that with some of the other stuff, it nailed the diagnosis that it was him.

9/11, the Towers; I guess the temperatures were well over 1000°, so things melted. But a lot of the identification was through oral structures, so we’ve talked about all the variation in teeth.

And then finally the infamous Adolf Hitler. He died in his bunker, but he had really bad teeth. He was notorious for traveling with a dentist; it was that serious. He had to have a dentist right by his side. You might have thought it was another General, but no; it was dentist.

So anyway, those are three people that come to mind that this whole field is really good in not only crime, but it’s good in natural disasters, plane wrecks, hurricanes, fires, things like that.

Okay. Well I Googled criminal cases solved through dental forensics, and there was a lot of fascinating reading that came up if you’re interested in that kind of thing.

Oh, that would be.

And then also you can subscribe to the International Journal of Forensic Odontology – it’s an online publication – if you want to see what’s currently happening in the field of dental odontology; forensic odontology.

I have a question for you.

What?

Is there a school, or is there a track, a pathway to take training in this? Or is this just people that are interested in it and then they become one?

I think they’re trying to make it more of a formal track. But I do think that – I mean you did some work like that just in dental school, correct?

Cadaver work.

Okay. So think that they’re trying to make it more of a standardized track that you can go on.

Good!

Okay, well you’ve heard the expression: dead men tell no tales? Well perhaps their teeth do.

Oh, that’s good.

Okay. We have a great show for you today. Let’s get going on it.

Okay, so today we have another installment of The Dark Side. So in this segment we discuss certain issues that some may say cast a dark shadow on the noble profession of dentistry with its primary goal of healing and helping patients. This segment potentially addresses certain controversies, inequity, self-interest, questionable ethics, dangerous products or technologies, and even cover-ups. So last time we discussed industry payments to academic endodontists, highlighting the importance of declaring conflicts of interests. Today we’re going to talk about an endodontic product, initially touted as a game changer when it launched in 2004, but removed from the market ten years later. You can probably guess what I’m talking about, because it’s written right there, but I’m talking about Resilon. And maybe Dad, you can start off giving us a brief overview of what Resilon even is.

Okay. I digress. The whole reason that we’re talking about something that launched in 2004 and it’s gone, is we want to learn something from this lesson.

Oh, and we will. You’ll see what we’re going to learn because we’ll definitely bring it home at the end.

So now that we have you on the edge of your chairs, and why are we talking about something old when everything that’s old is new again? In 2004 it did launch, Resilon, and it was heralded immediately out of the blocks – I mean it was banners and planes flying over dragging banners behind them. There were roars in stadiums around the world, - and if you believe that, you’ll believe anything I tell you. But there was a lot of noise in the marketplace, and it was heralded as a material to replace gutta-percha. It had an improved formulation; it was Resilon, and that’s a very special – I don’t want to go into the chemistry, but it had some properties that were interesting. I’m not going to go into all the little buzz words because we’re going to talk about it in just a moment.

So it was going to be able to bond to dentin, so this was very, very intriguing because it could bond to itself and to dentin. So then that was – we’ll talk about monoblocs in a little bit – but that was very encouraging. And then of course the early work, the benchwork, said that it sealed as well as, perhaps even better than gutta-percha. It had bonded; there was some noise; there were drums playing that strengthened roots and increased fracture resistance. But the work was all done on the bench, in vivo -

In vitro.

In vitro, in the lab, by one or two people; and they were not, in my opinion, dentists.

Okay, well just to provide a little context. In the early 2000s there was a lot of hype in the endodontic world around a concept of a monobloc; much like in recent years there’s been a lot of talk about minimally invasive endodontics, or MIE is such a hot button topic right now. And this is important because products tend to come to market in response to demands of the marketplace and what’s currently trending. So why don’t you elaborate a little bit more on what this monobloc concept is?

Okay. So I’ll have to back up just a little bit. But when we say gutta-percha; you know you grab your gutta-percha master cone, gutta-percha, you’re thinking it’s gutta-percha. Now when you grab the gutta-percha master cone, it’s about 18-22% gutta-percha. The bulk then is zinc oxide; that’s the filler – listen to these words carefully – then there’s a barium sulfate for an opacifier radiographically. Resilon, you’re thinking it’s a Resilon cone. Look at that; looks just about like gutta-percha with the coloration. Well it’s about 18-22% Resilon. That means there is a filler. And what is the filler? Nobody ever bothered to ask. It’s polycaprolactone; we’ll talk about that more in just a moment. And then it has a vernal pacifier so you can see it radiographically, so it has a nice radiographic density to it.

So that’s a little bit about the two materials that we’re comparing; the time honored gutta-percha and the new one that was heralded to be perfect. So resin could bond to the sealer. There was a resin cone; there was a resin – Real Seal was the commercial product, brand name, Real Seal. So the sealer would bond to the cone, and then the sealer would bond to the dentin.

So if you took a section axially through the long axis of the tooth, you could see what was described as almost a lack of delineation between the various materials. It was like a uniform block all the way through.

I’ll brag a little bit. I’m really invested in gutta-percha; not commercially. But gutta-percha when it’s warmed and thermal softened and pushed up against the walls, we showed in my master thesis at Harvard that it was about a 6,7,8,9 micron gap; and that gap was filled with sealer.

So if you did a section through that, you would see seams between the gutta-percha cone – even if it was mushed and distorted and up against the wall. You could see, in my case curved pulp canal sealer in that little 6,7,8,9 micron gap; and then there was dentin. There was no bonding, but we were able to get great seals. People longer than me could show recalls easily 30, 40, 50 years; I’m showing recalls 20, 30, 40 years. So that’s a little bit of the distinction about the monobloc. That’s why it was heralded. If it could really bond, then it would be maybe even strengthening the roots. But then you’d have to have a material that had about the same elasticity as dentin, and it didn’t.

Okay. So as it turned out, you were approached by the company Pentron, and you were asked to be an advocate for Resilon. And you were initially intrigued by the product, so you tentatively accepted; but you wanted to do some of your own lab testing. So why don’t you tell us now how it was that the company approached you, why you were interested in it, and then what you discovered when you were doing your lab tests?

Okay. Well I’ll tell a little bit more later, but you know, Pierre and I are dear friends. You stayed in his apartment off his office for months.

Right, Pierre Machtou.

Professor Machtou; and Anna Cohen who is a fabulous endodontist. So basically Pierre was going to come over to my histolab – we did this from time to time – and we were going to work shoulder to shoulder. It was terrific fun, I tell you. We talked about anything and everything, and we discovered the future of endodontics together – we thought.

So I decided in preparation to show Pierre this newfound material that was so incredible – it was heralded as being the game changer you mentioned – I decided I’d get 50 molars, and that’s not so easy. These are natural teeth, mandibular maxillary molars. I cleaned and shaped 50 systems, at least. I’m sorry; I must have shaped 200, 300 canals in those 50 teeth. Three times 50 is 150; they all had three. So I made these really nice shapes, and then when Pierre came he could just sit down and pack. And everybody out there knows it takes moments to fill, so we could do an enormous amount of work.

So Monday we talked about everything; I shared all the information I knew about it with him. I showed him my teeth, and I think we got started about mid-morning and we started filling. And it was a wonderful day; we were filling and setting aside, filling and setting aside. And then we came in the next day – because he was here for a week; five days together with Pierre. He’s got a birthday coming up. Anyway, that’s not – he’s 80 years old. Oh happy birthday man!

So we started working on the second day, and we picked up the teeth we had packed yesterday, and we noticed the cement was runny. We could take the cement and we could streak it and write our names with it; and we thought that’s odd. So we called Martin Trope because he was the academician and clinician behind the material, and he had worked directly with Pentron. And I said Martin; I think I know how to do this, but I’m not getting the set. What do you think? And he said well Cliff; it takes an anaerobic atmosphere. You can’t have them on the bench, they’ve to be in an anaerobic environment.

So we took all the teeth from Tuesday and Wednesday and Thursday and threw them in water. So when we packed them, there was a cup, threw them in, now it’s anaerobic. We noticed by Friday we could write our names on every single tooth, whether it was Monday, Tuesday, Wednesday, Thursday or Friday; and I became really concerned what’s going on here. Because I had never worked on a bench and not seen sealer set up. So some set up really fast, as we’ve talked about on other shows; some can take 24-48 hours. But everything at the end of that week should have been set. So that was a very, very big, big flag.

Okay. So at that point in time you had to say no, I’m not going to be an advocate for Resilon. It launched without your support in 2004, and still the initial in vitro seemed promising. So now the phrase “the new standard of care” is being bandied about, and clinicians are using Resilon daily. Not you though.

Now let’s fast forward 5-7 years. Now what are you starting to hear from colleagues?

Well, I’ll make it really personal. I practice in a medical/dental complex, and there’s two other endodontists a few offices away from me. And I won’t mention names, but they’re my friends and I’m happy to have them in my complex. So one of them came over and he looked very, very dejected. And I said would you like to speak; you look like you have something on your mind. And by the time we got to my conference room and could close the door I saw tears in his eyes, and I said what’s up? And he said Cliff; every day on my schedule I see a Resilon failure. And he said they have new crowns on them and they’ve been posted and there’s buildups. And he said it’s devastating. It’s a small community and every day on my schedule I’m retreating one of my failures.

So he hadn’t heard my side of it, and I hadn’t really been lecturing on Resilon because of what I found. But I guess I was amazed how quick people jump to something new because one soul shouts out: Hello out there – it’s Resilon!

So anyway, I had to tell him what I knew and it wasn’t really public information yet. But now I want to get back to that what’s beyond the 18-20% Resilon. And what it is, is this stuff called polycaprolactone; PCL. And that is a biodegradable, bioresorbable material. It washes out, gets carried away, and it opens up the root canal system to massive secondary leakage. So I had to tell him this in a very gentle way with arm around shoulder, because he’s a good guy; he’s a good clinician. He trusted an academician; he trusted hype. He heard monobloc, replaces gutta-percha, strengthens roots. Who’s using gutta-percha? If you’re using gutta-percha you’re old fashioned; it’s over 100 years old.

I don’t know if we have time for a quick story. I was at the ESE meeting in 2005 in Dublin, Ireland. I was on the second row. The room was packed; Martin Trope was the lecturer. And he said to everybody; you’re all using gutta-percha, right? Who’s using gutta-percha? So we all raised our hand. He said you have a lower standard of care; there’s something far, far better. You need to come over and listen to my lecture and get up to speed everybody, because it’s 100 year old material, gutta-percha, and I can bring you into the future.

So he said I want to show you 50 failures; 50 gutta-percha – said the word – gutta-percha failures, and it’s going to go really quick. Bam, Bam, Bam, Chung, Chung; all these failures were coming up. When he was all done, I raised my hand. And he would not answer my question, and he walked back and forth a few more times, so I made it so unpleasant that finally he said Cliff; I can see you have a question. I said you just showed 50 failures. I grant they were failing, but not a single case failed because of gutta-percha. I saw broken instruments, missed canals, perforations, blah-blah-blah, short fills, rips, tears. So that didn’t set for a good friendship for quite a while. But I will say to the camera: Martin and I have made up. We gave each other hugs coming off of Mackinaw Island many years ago, and he’s a good guy.

Okay. Well I want to point out now that Resilon was removed from the market in 2014. There were still peer review studies, long-term studies in process at that time, but I guess they had to remove it from the market even before the studies came out because it was -

That’s so amazing, isn’t it?

Right. So why don’t you tell us what these two important studies showed, that supported your personal observations, obviously. But why don’t you talk about those studies?

I don’t want to leave anybody out, but I’m just going to cite two papers. Because I think you said it – they’re often cited. And one was from the Barborka Group, 2017 and J.O.E. And then of course there’s the Strange Group, and that was in 2019, two years later. And just to quickly sum up what I got from the abstract and the paper itself, and looking at the methodology, is that gutta-percha was successful about 88% of the time at 6.6 years.

Resilon on the other hand was 56% successful at about 5.8 years. So we can get rid of the 6.6 and the 5.8; 88% successful; 56% successful. They clarified further that there was five times the failure rate with the Resilon group, and when they failed – this is interesting – they tended to have radiolucencies around all of the roots. See, when I have a failure, and say it’s a maxillary molar, usually we’ll have problems with a single root and the lesion will persist. But for all of them to leak on almost all the failures they saw? It was statistically significant.

So that was kind of the highlights from two papers. And again – I’m going to say it again. The product came off the market in 2014 and the studies were published in 2017 and 2019. That’s how dangerous things are. It went all those years, over a decade, with millions of patients receiving Resilon, because of what? Bullsh*t!

Okay. Well one thing we read when we were preparing for this segment is a nice summary of the whole Resilon disaster by Dr. Stephen Cohen; editor of Pathways of the Pulp is how I know of him.

Oh, that Facebook post.

Yes. And it was – the summary was in the form of a lengthy Facebook post, and we will have it in our show notes, or a link to it.

Oh good.

But he did point out in the summary what he called one of the major problems in endodontics today, and I’ll quote: “The pursuit of commercial gain through rushing of new materials into the marketplace without adequate research to confirm their efficacy.”

So what advice does he give to clinicians – and I think we have a list too that we’ll bring up – to determine if research on any given product or technology is credible?

Well I think Steve pointed out, Steve Cohen, in no particular order; the design and the methodology is critical. You’ve got to look at how the study was set up. Is it even fair, or is it already slanted towards a conflict of interest? Is the sample size quite small, or has it got a big enough in that there is some statistical analysis that’s meaningful? So I think is there research; is there peer review research? Is there collaborative research? (Did you hear that?) Research, collaborative research, peer-reviewed research? Not just some little Dentistry Today article – which I write in Dentistry Today a lot; I love Dentistry Today; it’s one of the most commonly read booklets for endodontic information. But it’s not a science booklet.

Okay. All right. Well looking back in retrospect at the whole Resilon disaster, and the conditions in place at the time that fueled both the rise and eventual fall of Resilon. There was a lot of buzz around the monobloc concept, and the market responded with new technology. The charge was led by a respected leader, Dr. Martin Trope, and there was a lot of pressure to adopt this product because it represented the new standard of care. I can’t help but see some similarities with what is happening today. There’s a lot of buzz around MIE. New tech is created, for example GentleWave to clean minimally prepared canals. There’s no peer-reviewed research, or very little peer-reviewed research to support GentleWave’s efficacy and safety. And there’s a lot of pressure by endodontic leaders to adopt this technology because it represents the new standard of care.

I hadn’t thought of it just like that, so that’s a terrific comment.

So I am just wondering what the long-term peer-reviewed studies will show when it comes to some of the products that have come to market in recent years in response to this whole MIE thing.

I do also just want – before you give some closing remarks, I just want to add that we have done a podcast recently, and it’s on new technology that comes to market, and how it drives or doesn’t drive the standard of care. So you might want to check that out, because you might think those two – technology and standard of care – are intertwined, but maybe they’re a little more separate than you think. So what are your closing remarks?

Well I think I got nailed for this by a guy – I’ll say his name; John Khademi; very smart guy, very gifted. We don’t necessarily agree on a lot of things clinically, but John Khademi got very confused when I said this expression: We need to create a future that’s not about the past, but takes the past into account. What I meant was, here by example, is Hydron. 1970s, heralded as a new obturation material. It was horrible. It was a disaster; within a decade it was off the market. There were thousands and thousands of failures.

So you would have thought when we got up from the’70s to 2004 we would have been a little antsy about these new heralded obturation materials. No! Resilon straight in there! And of course when you have an academician behind it, it even has more power; because some people in academics crank out a lot of peer-reviewed papers, so they’re already at a high level of confidence from the members.

So Resilon. I wanted to talk about what I’m thinking. You just played off your minimally invasive preparations. I don’t even want to – they’re not minimally invasive preparations. Let’s make the clinical distinction between appropriately well-shaped canals and minimally instrumented canals. There is a big, big difference, and Gary Carr can shed some light on that. In fact recently some teeth were extracted that were done in the mouth, in vivo. They were sent to Gary Carr because he likes to do this; he’s phenomenal at it and he does an assay, he does histology. And these were in canals that were prepared minimally invasively. Just to be specific, like a 17.03, a 14.03, really small. He found lakes and pools and sheets of necrotic and vital tissue in the apical thirds. So yeah, you might have GentleWave, but you’ve maybe made a needless complication to a non-existent problem. Just shape and get the deep shape we always talk about, and a lot of inexpensive ways to clean. Well GentleWave would work perfectly in a well-shaped canal.

So I saw that and I tied together your two thoughts – minimally invasive. It’s led to the single cone technique; it’s led to a tricalcium family of sealers that Josette Camilleri, one of the world authorities on it has cautioned us about. There’s a lot of things we don’t know. And the chemicals they use during irrigation sometimes interferes with the obturation materials.

Okay. Thank you for that great discussion. I just want to add; be wary if someone is putting a lot of pressure on you to buy certain technology because it’s the new standard of care.

Maybe horse and buggy.

Okay, well that was a great discussion, thank you. And we’ll move on now to show and tell. Or maybe it’s your lecture now; I’m not sure which is next.

I’m going a lecture at the board.

All right. Today we’re going to talk about something that happens very suddenly and very quietly in your practices, maybe about 10% of the time, and it has pretty much an unknown etiology – we’ll talk about that in a little bit. And that topic would be resorption. So as these cases start to come in, you’ll start to see each of them have their own distinct problem. And some them are pretty obvious to you and they would be picked up by anybody’s panel. But some of them you might look at your films, your periapical films, or you might look at a quick scan and you might say nothing here to see. That’s pretty interesting isn’t it?

So if you start to look, we have resorptions. Now I’m going to talk about internal today, but you can’t talk about internal without briefly mentioning external, and that’s another whole bag. But you can start to look at that distal root, and there’s quite a curve there, and you see that bulge right there and that is a problem. This is what we’ll look at later. Do you see it? You’ve got to push in here tight and you’ve got to look at it. You see stuff down here and it looks a little strange in here, and I bet you didn’t see the infra-body pocket did you? Oh my! And then this is a different kind of a resorption than this one, so this one is nice and round and this one is like really, really ragged.

Did you see that punched out area? Did you see the furcation? Did you see this one? Canal goes down, down, and it kind of gets bulgy about right in here. And we might even have an instrumentation problem because we might have some reverse apical architecture.

And of course we can see more resorptions on an anterior abutment; big ones that are obvious, everybody sees this stuff. And then we have our old friend; we should have bone. You can see the bone there and the bone should be like that. But wait a minute; we have an infra-bony pocket because we have resorption attacking that root and there you go. So there’s 10 cases, I believe. Last night I took out 4 of them because there just isn’t time.

Okay, so I have a library of several thousand slides, and usually over all those years you might have seen me out there on the road, or if you came to Santa Barbara and you were one of those people. We normally focus on clean, shape and pack, and retreatment and surgery. I have never really talked to many people about resorption. So I have a whole library of resorption, and I promise you we’ll revisit internal, we’ll revisit external. And we’ll talk about the external ones even more because they are more tricky when they’re in the apical part, versus the middle third, versus the external cervical inflammatory resorption, and I refer you to periodontal Pure Dental Learning; Terry Pannkuk. Pure Dental Learning; he had a wonderful presentation on external cervical inflammatory resorption.

All right. So if we just kind of blow these up you get one more chance to see them very quick. Some of them are again very obvious. Most important; most people are asymptomatic. So they are walking around, eating and chewing equally well left or right; they’re not reporting really thermal; everything seems to be fine for them. So it’s up to you to catch that 10% and that’s not an insignificant number is it; 10%.

So if we keep moving along here, let’s come back and look at that bottom right one. That one is really a problem. I’ll just say this today. External resorption; it occurs on your developmental pre-cementum; the developmental pre-cementum. And it’s either lost or denuded or injured. And then you have cells adjacent to that in the PDL, and they attack those denuded injured surfaces, and that’s what starts the whole ball game. So it’s an outside/in problem. And it can be very, very damaging, it can be very, very invasive, and it can go very, very quickly. Obviously when somebody fistulates, they have bleeding out of an infra-bony pocket like this one. And obviously when it really deteriorates to this level – look at that – to that level, people have symptoms. Of course they do. I’m talking about the silent ones. And by the time they get to where people come in an tell you about it, it’s oftentimes really late. Sometimes surgical intervention can kick in and save some of these teeth and push it back to a higher prognosis. But oftentimes it’s sayonara. And then it’s the age of implants or bridgework if there is a posterior abutment.

So you can see, external is very invasive, very moth-eaten, very tough to get in here in a proximal and do the repairs. We’ll show some of those – not in this lecture, because again this is more internal where everything’s going to be done inside. Okay, so there you go.

Okay. How we’re going to see these things, to come back to the three ideas, would be radiographs, so I’m going to stress three angles. And I would like you to come from the mesial, I’d like you to come straight on, and I’d like you to come from the distal. And I’d like you to come about 15° from the distal, about 15, 20, 25°, doesn’t matter, but swing that head around and then you’ll be able to see things. And here’s what I’m trying to show you. If you come from different angles and you have this kind of a situation. You have a pulp in here, and if it’s deteriorating, and you have internal resorption we’ll pretend. If you come off axis and you do a cross-section over here, pretty much the resorption moves with the canal and they’re always together. If this is separate; if the resorption is from the outside in and you come off axis, either way what you’ll do is you’ll be able to have a canal – you’ll have a canal and the resorption then would be maybe like that. So it would be – in this angle it’ll look like they’re stacked up on each other, and this angle you can separate them. So if you can separate, then you know it’s from the outside in.

All right, total synthesis; we’ve talked about that, Professor Tyndall has talked about that. But you have a head that gives you 7 X-ray drives if you will. You get 7 images with a single X-ray. And you can get stacks; you can start to look at various X-rays in that stack to get multiple views. So you get a very clear picture. So it’s more than radiographs; perhaps less than CBCT. Because with CBCT you all know we get the coronal slice; we get the what? The sagittal slice. And we get the axial. The axial slice.

So when we get those three views, you can really, shape down the resorption in terms of how much destruction has happened, the proximity to the canal if it’s external, the proximity to the edges of the root if it’s invading and getting ready to perforate. So the axial slice turns out to be really a hero view that we can get only with CBCT. So that would be a little bit about that.

Okay. So there’s types. And again, I’m not going to labor too much on this one today, because it’s a whole story. but let’s remember that internal is the pre-dentin. So it’s the developmental pre-dentin that is lost or injured, and against that injured tissue you have cells. So if you have a tooth in here, oftentimes there’s an injury. The injury could be related to trauma – we’ll get into that – but it starts at the interface, right where the pre-cementum, or the pre-dentin is injured. And then the cells adjacent; the pulp cells, the odontoblasts become odontoblastic; and they start eating away and eating away and eating away. And sometimes it’s a very slow process; quite circular, quite round. Sometimes if it’s inflammatory – if it’s inflammatory you get this really moth-eaten – and we’ll show a case like that.

So be sure to really think about surface, how it starts. The replacement is just a progressive eating away at the tooth structure. Inflammatory is very nasty, very invasive, and sometimes quite difficult to treat because there’s a lot of bleeding, a lot of bleeding. Bloody canals.

All right, so let’s look at one. You can see it right here, right in the middle 1/3 of the tooth. You see it’s pretty calcified; we don’t really have much of a canal. You look in here; this is narrow. This is a little bit narrow. But look at this; this is wider over here; quite a bit wider. So there’s been trauma. And I didn’t say this, but of course we’re going to have to put down the etiologies. There’s several: trauma. Trauma could be a car accident, a bicycle accident, a hockey stick, and elbow, something like that. But trauma could also be from caries. Deep caries; invading caries. Trauma from caries could also be from the mechanical work. When you do mechanical dentistry, you’re air drawing and you’re drilling. You have to worry about what? Heat. You have to worry about heat generation. Heat transfer is not real good through dentin, but dentin can conduct. And if you get up a little bit more than around 8,9,10° you’re going to have damage to the pulp.

So we’re looking at etiologies if you need a title: etiologies. Trauma, caries. We can have grooves, developmental grooves; I could just say like a dens – we’ve talked about these before. We can have all kinds of things. Orthodontics -- I guess I should write it down just so I can offend one more group of people. The orthodontists never like to admit this: almost all kids in American it seems like get orthodontics. And then there’s too much movement, there’s too fast movement. Okay, so pressure on teeth to try to move them.

So resorption, just to think about this. Not all resorptions are bad, are they? How about the baby tooth that is resorbed away naturally, physiologically, as a succedaneous tooth erupts into the mouth. So that’s an example of pressure resorption, but you can get pressure resorption from orthodontics.

Okay. So if you have your CBCT, you can get a slice right through here, axial, and you can see that this is quite a bit bigger than this dimension.

And it all makes sense to you, because if you look over here again, you can see how big the canal is. You can see that there’s a difference in size, central, and the contralateral central is that one. And of course on the sagittal slice you can see we don’t have architecture. The canal should be pretty sharp, should be coming right through here like this. But you can see this is all eaten away on both sides, so just a quick example of that.

So back to the treatment. Make a careful access; measure twice, you can only cut once. It’s pretty calcified; you’re going to be drilling from the incisal edge. There’s the tip of the root; you’re going to have to go up to what? About mid-roof, so you’re going to have a long channel to get up there. And then the key is when you get up there, you have to think about picking up the canal on the more apical segment. Because your file is going to get ledges and irregularities; it’s not going to be a smooth slide path. So it’s going to be a little tricky sometimes, feeding it through a bunch of bleeding and blood in some cases; and then picking up the canal in the more apical segment. But if we do that, we can get the pack, and you can see it’s pretty fun.

And this is just old fashioned. A guy – one of my dear friends, I’ll say his name: Yosef Nahmias, up in the Toronto area – talked about horse and buggy endodontics. This is horse and buggy endodontics; it’s about an hour and a half. About an hour and a half. So old fashioned ways to irrigate. You don’t need GentleWave; you don’t need lasers to clean lateral canals. But if it helps you and it makes you get things you never got before, stay in it. Stay in it.

So if we look at it in a little more animation world, you can see how these things are. And of course what you want to do is start planning. So fortunately when we made ProTaper Ultimate – and yes, I have a commercial interest in ProTaper Ultimate, because I’m a co-designer with Pierre Machtou and John West. So this is the only instrument in the world like this. This is one of those auxiliary finishers. And this instrument is a 50/10; has about 7mm of flukes. So you’re going to be able to get a nice, controlled capture zone in the apical third. Obviously the file is never going to get into this area; there’s no chance. So irrigate, irrigate and irrigate. And when you’ve forgotten what to do, re-irrigate.

But then of course some activity on that would be useful. If you could then realize after planing and shaping, there’s a lot of pulp in the lateral canals, there’s still inflammatory tissue that’s going to continue eating away at the root. So this is where we can talk about agitation. You can do it with GentleWave for $100,000; you can do it with lasers for about $60,000; you can do it for about $2000 with the Smart Lite Pro EndoActivator. And just for GentleWave – this is only for GentleWave – I’m an inventor. I get a royalty off of this product. But you know what? It’s about – well it’s almost 100 times less money. And it can move a polymer tip that doesn’t cut; it can agitate your irrigations, you can clean lateral canals, we have evidence now for almost 20 years. We have over 50 scientific papers, so it’s not so bad at about two U.S dollars per tip. Per tip.

So you agitate, you follow the cycle, and that is pretty good; except what? I want to introduce TCA. Dr. Terry Pannkuk, again, at Pure Dental Learning has talked a lot about this, and I’ve helped him with Webinars where he’s talked about trichloro acetic acid. It is terrific. If you just add the – take off 3 hydrogen atoms and add 3 chlorine atoms, you have that trichloro acetic. It’s a great hemostatic, and it doesn’t leave that black coagulum. And it’s a disinfectant. So you can use TCA to help you better clean in the un-instrumental portions of the root canal space.

When we close these teeth, don’t be in a hurry to pack. Calcium hydroxide comes to mind; pH is around 11 or 12. Most of your acidic reactions are very acidic; about 1 or 2. So you have a base competing against an acid, inflammatory cells; it neutralizes that. So we will put calcium hydroxide into these canals.

So in this case – we’ll go quite quickly now – you can see this is a classmate of mine from Harvard, and he has a huge internal resorption defect. He had these both treated by an endodontist, on staff at Harvard, in 1974 or 75. One tooth looks kind of odd, but it’s working 40, 50 years later; so round of applause. This one’s not doing so well. So you can see carefully how you might pull that cone out. You don’t want to use chemicals and get a slurry of chloropercha out here where you’ll never get it out, and plus it’ll block your irrigants. So let’s think about getting that out. We won’t go into retreatment, but this is Hedstrom displacement. You can already see it must have perforated somewhere; must have perforated somewhere. Because once that cork comes out of there – that’s that little cone – guess what? It is a pool of blood, and this is what you’re pretty used to seeing in some resorption cases that are internal. So you’ve got to stop the bleeding.

So what I like to do is take a cotton, squirt in some calcium hydroxide. You’re not trying to squirt it to length; just get it in the body of the canal. Use the EndoActivator and slap that toothpaste type viscosity material, calcium hydroxide; throw it up into the walls, throw it into the un-instrumental portions, throw it into the resorption defect. And then get on it with a cotton pellet on the coronal part; put a plugger on the cotton pellet, and push. And that’s just like packing thermal softened warm GP in the narrowing cross-sectional geometries; it’s a thing of beauty. Out with the lateral canals, out with the anatomy, and out with the resorption defect. You can see in only a few more minutes; you can see the bleeding has arrested and we can go ahead and pack. But I left calcium hydroxide in there for a little while. Because you can have calcium hydroxide stay in there 30 days; you can have it for 60 days, 90 days. There a few studies that show if you leave calcium hydroxide inside you for a long period of time, maybe even a year, you start to weaken the tooth at the cervical region. So be aware of that with the risk versus benefit assessment.

Anyway there you are, packed off tight. You can move warm gutta-percha into clean surfaces; you can get great adaptation. In my thesis at Harvard, the interface between gutta-percha and dental walls was 7-8 microns. So the sealer is the gap; it’s in that 7, 8, 9mm gap. Just a thin layer of sealer; wall-to-wall thermal softened GP pressed up against the wall; out with the anatomy.

So you can see this physician - you don’t know he’s a physician – I know he’s a physician; he’s got a very nice little bridge in here. Look at this. Flat roots, flat roots, history of ortho; and a pin, heavily restored teeth. Heavily restored teeth can undergo resorption. And so basically you say what’s this though? That looks a little funny to me. If you really think it looks funny and he’s got a little bit of symptomology, there’s maybe a little thickening of the PDL; not necessarily up here apically, but it’s more over here laterally. So careful access. Probably took me about an hour to get an 06 to place. Another visit to do the shaping and the cleaning and the packing. But the thrill to fill is there. A lot of times in resorption defects, even lateral canals can start to resorb.

Okay. You want to see a bloody one, this is a bloody one. You won’t see a single drop of blood, so relax. If you’re out there eating breakfast, continue eating. It’s time to have some strawberries and cream. This is a very moth-eaten, ragged canal. If you can start to really look at it. The contrast is tough because we have tori. You see those white tori coming across the roots? That’s exostoses; that’s bone. So it’s kind of hard to see it, but it looks different than the clean canal that you see next door that is really shutting down. I have a grandson that has a shutting down canal like that. How long can it last before there’s not enough blood supply you ask?

Okay, then you do the shaping. It’s hard to get files through here; they bounce off of the irregular surfaces; it’s ragged, it’s bloody. It’s going to be EndoActivator time with calcium hydroxide, so squirt it in a little bit. Throw it up against the walls again to be redundant with the EndoActivator, put the cotton pellet on and a plugger, and push. Take a post-op x-ray and you’ll see white calcium hydroxide – not as white as gutta-percha or sealer – but you’ll see the contrast on the radiograph; and you want to see it to length. And it’s okay to even see a little puff sometimes.

Then you get that out on a subsequent visit; flush it out. How do you get it out? EndoActivator again. You get it out because you can’t get it out necessarily with a file, so get it out with the EndoActivator. Clean surfaces, get the cone and cap it.

Will this is a bridge above it. A well-fitting crown used to be like that. This is a big amalgam repair, and when you start talking about cervical caries and the distant from the cable surface to the pulp chamber, it’s not so far. It’s not so far away when you’re from the buccal or the lingual, because those horns not only go up into the occlusal table area, but they also – Engel, John Engel described horns that went out to the buccal; horns that went out to the lingual. Pulp horns that can get nicked by those repairs.

So what are you going to do? It’s going to be kind of a tough case; you might want to think about referring it. But I know the people that are on this show are so dedicated to Endo; you’re so passionate – I mean you’re junkies, you’re Endo junkies. You’re not referring this. You might think about it. You might live to fight another day; you might learn something by referring.

So if you’re going to do it, be sure you do it just like it’s possible to do it. Look at that; all filled in nicely. Something going on down here. But look at all the anatomy. You see anatomy up in here between the canals; you see a furcal canal. And if we bring in another view; whoa! We’re lined up and there we are again. But look at the curvature and how we can flow around, get our irrigants down there, get our calcium hydroxide in here. Calcium hydroxide necrotizes vital inflamed tissue; TCA eats that stuff up. So now you have space. Now use a warm gutta-percha. Don’t try single cone. Come on people! Horse and buggy endodontics has been around for like 60 years; it works! There’s a time to be all high tech and there’s a time to know the old fashioned moves. Because some of these newer ideas just don’t take into account everything you see pathologically.

And the last case. This one came right out of a gorilla. I think the length here, according to our digital x-ray, anticipated is about a 32mm system. Do general dentist want to do this case? I didn’t even want to do this case! I said is Buchanan in town? Is Terry Pannkuk in town? Who’s in town that wants to do this case? Nobody wanted it, so I get it. That’s a joke. The dentist tried to saw the crown off; he couldn’t get the patient numb; they were hopping around in the chair. It hurt! That’s a highly inflamed tooth; he couldn’t get it with a block. He got the lip numb, but it wasn’t enough. He didn’t know about supplemental anesthesia.

So we went ahead, got the crown off, made the tooth about 28mm. And that’s shortness, so I could get it on 31mm files. I wanted to knock the damned thing clear down to here so I could use 25mm files and get my fingers closer to the tip of the instrument for more dexterity and more control. But alas; this was three visits. Proud to say, because the patient’s got the tooth about 30-some years later. But we left calcium hydroxide in here a long time. Sweeping curves, shapes that are appropriate for the roots that hold them. Shaping is what cleans. Unshaped canals are only instrumented. We’ll talk about this a little bit later, but there’s tags of tissue left behind. We’re even seeing that now in the histology on the bench; with these narrow shapes, even using GentleWave technology. Sheets of tissue still present.

Look at this. This is like a pool; a lake of sealer in between who knows what? It would be fun to get that tooth out of there, right, without breaking the root; and start doing some slices, some axial sections, and see kind of how that looked.

So I want to leave you with this. I really want you to look for the 10%. I really want you to assume that everybody’s got internal resorption or external resorption. Talk to your patients; did you ever have orthodontics? Look in their mouth; they have a lot of dentistry. They’ve had a lot of teeth that have been heavily repaired. All these things, along with grooves and fracture lines and things like that, are all part of the history that will help you pick up internal resorption.

All right. We’re going to close the show today with another Show & Tell. It’s been a while since we’ve done one, because we actually find them a bit emotional.

Do you need a hanky?

No. Okay, so we’ve done two others so far; one we shared an object and then another we shared a photograph. Today we’re sharing something that is hand-written. So that could be probably something pretty old, right, because not many people write by hand anymore.

Very rare.

Okay, what do you have? You start.

I guess it was in 2000 – yeah, 2005; no, 2007 I guess, more or less; 2007. I had gone to the California Association, the scientific session, it’s in Anaheim, California. It’s down there every year annually, and I’ve probably done the meeting 20 times. But in that year it was very special because the whole family came. And it kind of actually startled me, because I was thinking you guys were going to Disneyland for the day; I was going to go give my lecture. And when I heard everybody’s dressing up; even my grandkids were putting on a suit and a little tie and stuff. They're all going to be in the front row and they want to watch Papa get started.

Well that was actually scarier than the 600 or 700 people that were there. And I remember clearly why I gave my opening remarks, and I could feel the energy in crowd. I saw – when I started my lecture, I saw little Isaac writing. And I thought well he’s bored out of his mind; of course he is. He’s writing something, he’s drawing – he loves to draw; he’s always drawing mechanical things and stuff.

Well you guys did get up about 30 minutes in, and you gracefully exited left, and you went to Disneyland. But some weeks later, not while we were down there at the convention center, some weeks later this arrived. So what he did is he heard the very part of the rationale for treatment. And in the rationale for treatment, he talked about – he drew a tooth. It had a root, it had a crown, it had pulp, it had lateral canals. And he talked about the importance of access. He talked about the importance of shaping because we were already turning it. It wasn’t cleaning and shaping anymore from the ‘70s; it was shaping and cleaning. We shaped to irrigate; he understood that and he got it down. And then filling root canal systems he thought was important. And he made some comments. Isaac, you’ll hear me – he’s in the control room. But he even crossed off bacteria. But he was dead right; he was just a little before his time.

So when I got this, I didn’t know what to do with it. I didn’t want to put it away and deep-6 it; that would be a travesty. So I thought, I’ll hang it in my histolab and I’ll see it every damn day in there. So I wrote the top line; and a lot of people came through – we were actively giving seminars in that era – and people would go what’s that? So I wrote that’s my grandson, Isaac, and he is the next great endodontist. So that’s the only thing that Ruddle did was on top.

So when I got that note, it’s meant a lot to me. It’s been hanging in my office for almost 20-some years. And I brought it in today.

Well, it might be a little less, because I know how old Isaac is.

2005, so 15, so yeah. Less than 20.

He’s 24 now. Okay.

But a long time. So it’s hung there faithfully all these years, and it’s just been fun to go in the lab and see it. Now Isaac didn’t go on to become a great endodontist. He went on to become the next great thing. He does so many things, I won’t even describe it. He’s doing injection molding, he’s doing laser printing, he’s doing 3-D printing, he’s doing helmets, he’s doing all kinds of stuff. Runs the control center, and he’s still discovering the path.

Okay, well I brought these.

Oh wow; those look old!

These are probably 200 years old. These are from Grandma, from Grandma Sawvel, Mom’s mom. And they’re handwritten recipes. And it’s funny because I actually have photocopies of these at my house. So when I make these things, I actually read these handwritten recipes; and they are hard to read. And she even put like about ¾ and then a number sign hard cheese. So that’s like ¾ of a pound; it’s just a different way of writing a recipe when you think nowadays. But what these are – it’s for patties and green rice, which -

It’s a vegetarian dish?

This is what we have – I think we’ve talked about it before on our show. The green rice is spinach in a rice casserole, and the patties are these vegetarian patties that are in a sauce. And this is what we have every Christmas dinner, every Thanksgiving dinner; Easter we have these things. This is our holiday dinner. When we do something fancy, we have patties and green rice.

If you really wanted to enjoy your best ever Thanksgiving dinner, they can show up in Santa Barbara, and we’d give them a patty.

And my favorite dessert, which we just call Cherry Dessert, but I see actually it has a specific name; Grandma wrote Cherry Delight. So it’s just graham cracker crumbs, cherries and like a whipped topping. So this is my favorite dessert, and usually we have this on Christmas eve dinner, after dinner.

So those are traditions, huh?

Yeah. So anyway, it’s just kind of nice to have these original recipes that Grandma wrote. I actually – my mom keeps them at her house. Even for this segment, she brought them here to the show and then they’re going back home to her house.

This is the originals.

Yeah. But anyway, it’s neat to have something. It makes me think of Grandma too.

Well maybe the message then is take a little piece of time out of your incredibly busy life, you’re so important. And just jot a little note or a little picture to somebody and you’ll cheer them up, and maybe in 20-some years they’ll still be talking about it.

Okay. On that note, that’s our show for today. See you next time on The Ruddle Show.