Working Lengths and Troubleshooting Apex Locators – PDP216

Teaser:
In fact, you’re going to measure first, how far you’ve got with a rubber stopper. You’re going to take it out, you’re going to measure it, it’s 18. You’re then going to get a higher diameter file. Really what you want to be thinking about is the apex locator is the daddy. They’re the key. You’re going to be trusting that one person.

Essentially you’re just creating that kind of circuit. Do you want to be tickling those periodontal tissues and they said, they’re extremely, extremely reliable. That is the greatest thing about my job in dentistry. You never, ever, ever, ever stop learning.

Jaz’s Introduction:
Protruserati, you’re in for an absolute treat. My guest today, Dr. Samuel Johnson, will actually make endodontics fun. Look, I don’t do as many root canals as I used to, and to be fair it’s really not my favorite thing but seeing the wonderful things that Samuel is doing is really making me excited and enthusiastic about Endo, which is why I’m so excited to finally bring him on the show. Not only are you going to enjoy his geekiness and how passionate he is about Endo, he’s also going to charm the pants off you. Just such a lovely guy.

This is part one of a two part special. So in this part one, we look at apex locators and we look at the difference between the radiographic apex and the apical constriction. So basically when you see a radiograph of a root canal and you think, Ooh, that looks short, or, oh yeah, that looks to length quite often, we are wrong. And if you use our radiograph alone as a metric of success, then that might be lying to us. Along with that, we’ll talk about what makes apex locators reliable and what makes them unreliable.

The power of glide path files, which Samuel’s really big fan of. And Samuel will share with you the ultimate way to consent a patient. And this could be used for anything, not just for endo. And I am convinced that this way of consenting patients and then taking a photo of this way of communicating, uploading it to the patient’s notes is just absolutely phenomenal.

So whilst you’re going to level up your endo in this two part episode, you’re also going to be better at consent and communication. And as ever, I always like to dive in about the journey of our guests. And Samuel’s got such a fascinating story about being in the army, an engineer, then the endo MSC, he’s got three kids, it’s all happening and he is just brilliant.

Dental Pearl
Every PDP episode I give you a Protrusive Dental Pearl and it’s taken from this episode thanks to Samuel. Look, do yourself a favor, go on Amazon and buy a small whiteboard with a marker pen. Then you’re going to use that whiteboard in all your communication with your patients. Every time they have a crack, you’re going to draw a tooth with a crack.

You’re going to show the patient all the details, draw it for them, highlight it, write the pros and cons, write the fees on this whiteboard. This is a powerful way to communicate and consent. You take a photo of that, then you upload it to the patient’s notes. I know many of the protrusive community have also used this technique before, and those who use the whiteboard in surgery absolutely swear by this technique. I appreciate it’s not for everyone, but some of you will really resonate with this and I truly think it builds a nice connection and high level consent for your patients.

This episode is eligible for CPD or CE credits because we are PACE approved. So once you finish this episode on the Protrusive Guidance app, scroll down, get 80% of the quiz and you’ll get your CPD. Let’s now join Samuel for a fantastic geeky endo discussion. You’ll love it.

Main Episode:
Dr. Samuel Johnson. Oh my goodness. I love the pulp. It is so, so great to have you on the podcast today. How are you?

[Samuel]
I am super, super excited for today. Really excited.

[Jaz]
You make endo tangible. This is why I wanted to connect with you. This is why I wanted to bring you on the show, cause everything we do in the podcast about making dentistry tangible and what you do with endo is the best I’ve seen. Like if I were straight off the bat, I want to say everyone needs to check out your channel and your videos and your Instagram. Just beautiful.

[Samuel]
We drop a live video of a root canal every Friday, and each Friday we do kind of, it’s like a theme. Okay. So last week was minimal opening. The week before that was pulling out silver points. And essentially what I like to do is I record every single root canal I ever do, ever. I’ve got this huge kind of cloud based system at home, which has got a 40 terabytes of footage.

And then sometimes when I’m doing a root canal, I’m feeling the magic. I’m feeling something’s happening. I’m feeling maybe this will be a great learning experience. And that’s what essentially every Friday, we try and drop something exciting for you. For sure.

[Jaz]
I’m so glad that you do this. It’s a real service and you see from the love that you get on the comments that people really needed this. Right? Okay. So I’m so, so, so happy to connect with you and talk about a topic that’s very dear to your heart, which is working lens, right? Working lens, figuring them out. Apex locators and troubleshooting.

But actually, I’m so tempted to go off piste, off script. I’ll tell you what, we will do like, we had so many questions from the community last night on the Protrusive Guidance app, I had a message saying, okay, I’m speaking to Samuel Johnson tomorrow, any burning endo questions and like, we’re going to need to block out like five days in the calendar just to go through this, but we’ll do what we can guys.

So just before we dive into the details and the geeky stuff, just tell us, for those who haven’t seen you before, seen your stuff, heard of you, I hope that’s always going to change, but just tell us about your journey. Why are you so deep into root canals?

[Samuel]
Well, I always tell a story all the time and people go, no, surely not. But I remember doing my first root canal at university and I remember thinking, wow, do you know what, I remember actually getting told what a root canal was, and it was kind of like this, you’ve got this hole, you don’t know how long it is, you don’t know how wide it is, and you’ve got to fill it all the way to the end, but you can’t go out the end or you’ll be in trouble, and that used to absolutely blew my mind completely, and I remember doing a central and a lateral, the very, very first one I ever done and it looked absolutely fantastic.

And the tutors came over and they’d be like, wow, this is really, really nice. And I was hooked straight from there. I, I knew this was the thing that I wanted to do. I just think it’s a crazy kind of concept.

[Jaz]
When you were a student, you knew this was your calling.

[Samuel]
Well, student at university in Manchester, yeah. You think to yourself, there’s so many questions, isn’t there? What are we using? How long, so yeah, I was hooked straight away.

[Jaz]
I almost went down the same path as you, Samuel. So I did loads of root canal treatments as a student, like far more than the average. I won the Tom Pitt-Ford prize. So that was interesting. So at the time I was like, okay, endo seems good. And everyone’s talks about having a niche and speciality. So I was very tempted, but then it’s just a stupid story. But I was influenced in a good and a bad way. I was on a train, literally I was on a train, I think I was like in final year, and I had the book, the textbook, Understanding Partial Dentures or something like that, like, in front of me, right?

And I was just staring out the window, wasn’t reading, and the chap, who I never know what his name was, really nice charismatic chap, sat opposite me on the train. He was a dentist, he said, oh, you must be a dentist student, you’ve got a textbook there. I was like, yeah, yeah, yeah, and then he asked me, okay, you know, what are you into?

I was like, you know what, I’m thinking of being an endodontist. And Samuel, you know what he said to me? He said, are you sure you want to specialise in something that’s this thin and that tall and like corner yourself into the tooth? And that bastard, honestly, he literally like, without one comment, like, I was reflecting on it and I was like, do I really want to specialise?

And then I’ll go into occlusion and then the bigger picture and that kind of stuff, but not to say that Endo, what you do with Endos. You just make it so fun. It’s challenging. It’s problem solving. It’s really, really technical. So, we all love what you do. And so I just extract so much from you today because it’s something that I want this to be the most tangible episode of Protrusive we’ve ever had.

And easily it will be right. And so just know from your content. So that’s why I didn’t go into endo, but the first question I have for you, then Samuel is how reliable, and this is for my younger colleagues, right? Because when I first qualified, you look at the radiograph, you do the working length, and then you try and go by the radiograph.

And then you start learning about apex locators. And then you realize, actually in a minute, my radiograph said 20 millimeters, but my apex locator is saying 17 millimeters. And so then you have this issue, and then you learn about the actual anatomy, which I want you to go into. So the question is, how reliable is a radiographic measurement of the working length versus an apex locator and how trustworthy are apex locators as a part B?

[Samuel]
I think this is a really really fundamental question and and if you are a dental student or you’re new to dentistry you need to get this concept in your mind. And I suppose what I always bring myself back to university. And of course we were taught how to use apex locator in university. I qualified in 2015, but there was certainly a push from certainly the older generation of tutors to sort of say, you take your comfort radiograph, you take your post op radiograph, you want to make sure that the obturation is between one and two millimeters away from the radiographic apex.

And in fact, the guidelines at the time, in 2006, we’re kind of advocating that, if you’ve got your obturation within two to one millimeters in the radiographic apex, then you’re going to get a good outcome. And weirdly enough, you go from university and I moved into practice, I went into VT and nobody used an apex locator in practice.

And I found this absolutely incredulous. And also, of course, when you move into a new practice, you want to sort of, copy everyone. You want to do what they’re doing. Cause you know what they’re talking about. And I’m probably one of the very, very first things I ever bought for myself was an apex locator.

And my first apex locator was a woodpecker, a really, really little known brand at the time. But woodpecker is a huge brand now in endodontics. And I bought it from Amazon and I’ve still got it today. It’s fantastic. Still don’t use it today, but you’ve got to get into your concept of buying things for yourself. Which sometimes it’s really difficult to get over.

[Jaz]
But some associates get really wound up by that. Oh, why should I, I’m on a percentage, the principal should be buying it. But sometimes, especially when it comes to equipment that you can take with you to another practice or carry around with you. And it’s going to really improve your outcomes. It just makes sense to, it’s a tax deductible expense. We always say that, just buy it yourself.

[Samuel]
Oh, I’ve bought thousands, tens and tens of thousands. I bought my own microscope.

[Jaz]
And I bought my own T scan as well. You bought your mic. So I bought my T scan.

[Samuel]
I am grand. I am this close to buying a scanner this close. I’m looking into, but the problem with me at the moment is I’m so deep into endo. And my microscope is like my fourth child. I absolutely love it. It’s fantastic. And when I bought it, I was still doing little tiny composites with it. And I love it.

[Jaz]
But, just because everyone will be wondering, is it CJ Optik? Is it Zeiss?

[Samuel]
I bought a Labomed Prima, but I am in the sort of, I’m thinking about getting a new one, but I use different scopes and dip, because I work in three different practices. So I’ve got my Labomed, which is, the channel is recorded all of off that microscope. I also use a really cheap kind of one in another one. I’m trying to think which one it is. And then I’ve got a German made one again. My mind’s gone completely blank, but it’s a really, really common one. But my  Labomed, I think is great. And I got that off Connor Bryant at the time. I don’t know if he sells these.

But then I suppose there are some factors into, when you’re factoring into why you think you might get a poor working length measurement from x rays, you’ve obviously got your angulation. If you’ve got someone who’s got quite a small sort of roof of the mouth or they can’t handle, x rays.

If you’re taking the x ray, not a perpendicular angle, you’re going to get a poor sort of results, poor sensors. Sometimes, believe it or not, not using thick enough files can sort of muddy the water where you’re going to be. But-

[Jaz]
What’s the minimum thickness?

[Samuel]
It’s 15, they say, but, we’ll get onto that because I use 10. I think that the main issue really with, with x rays is it’s obviously a 2d image and what you need to, again, get into your mind is the radiographic apex, the difference between the radiographic apex and the anatomical apex. So if you’ve not kind of heard this concept before, the apex is really, really complicated.

You’ve got this kind of major apical diameter, it’s kind of got like this kind of wide trumpet kind of blunderbuss kind of opening. And then you’ve got this minor apical diameter, and this is the apical constriction. And this is essentially where the canal space sort of pinches inwards, and then it sort of widens out.

And just for our less experienced colleagues, that is the point at which you want to be obturating to up to this constriction. And the difference between the major apical diameter and the minor apical diameter is about 0. 5 to 1. 5 millimetres. Now, this-

[Jaz]
But it could be as much as five millimetres, right? The difference in a radiographic apex, and apical constriction. I think so. Some studies show that actually there can be in some cases a big variation that can.

[Samuel]
And I think if you don’t mind me saying you are getting something else mixed up with, you’ve got this minor apical diameter and the major apical diameter. But what you need to remember is the way the canal moves, it moves in three days. So say, you’ve got quite a large canal and it’s reaching the end of the tooth and then it makes like a sort of 90 degree divert out of the tooth and your x ray is actually within the plane of this, this kind of, this bend.

When you take the x ray, you’re going to think that it’s short, but actually it’s where the canal space is bending out the way and you’ve got this sort of extra thickness of dentine. It’s a really difficult concept to explain without some videos and what I’ll do, Jaz, I’ll send some pictures for you to pop in there, the information.

[Jaz]
Yes, that’d be great. But obviously those on Spotify and Apple, you guys have been there for years. We always trying to make it a tangible, but for the YouTube fans, we’ll put the images on as well, as well, a link to a channel.

[Samuel]
I listen to all your stuff on the podcast. I don’t look at anything. I’m driving to work. My journey to work is about 50 minutes every day. It’s absolutely mental. But I think another concept you need to get into your head as well, is this sort of concept of portals of exit. So it’s really better to explain the apex with this portal of exit kind of thing, is that it’s just essentially the whole, okay?

And worryingly, to some people, there are many, many portals of exit, okay? So, you might think to yourself in your mind’s eye, you’ve got this one sort of main tube, and you’ve got this tube that sort of reaches out the end. You’ve got when it reaches between three to five millimeters at the end of the tooth, you’re going to have these many portals of exit. Okay.

[Jaz]
Is that lateral canals then?

[Samuel]
It could be lateral canals, it can be essentially where the main canal just splits into two. And sometimes when you obturate your tooth and you kind of see this kind of like sort of flaring out of all the little, I mean it’s beautiful when you see it, but this is essentially where you’ve filled the apex completely.

What I would say, there are advantages to x rays as well. They’re not completely useless. There are things that where what you see on an x ray is clear, and that’s overextended and overfilled. If you’ve overextended and overfilled, you know that from an x ray. And also, there is a distinction between overextended and overfilled.

Overextended, this is where you push the filling through the apex, you push the obturation GP point through the apex, but the canal space around it is not filled. And Overfilled is essentially where you’ve completely filled the canal space, but you’ve still pushed a little bit of the obturation.

[Jaz]
And so really it’s better to be a lesser of two evils overfilled is better than overextended. Is that right?

[Samuel]
Honestly, we could have another podcast about this, about should we seal a puff? Shouldn’t we seal a puff? My very, very good friend who’s a specialist in root canal. I’m going to name drop him Nick Longridge. Amazing mentor.

[Jaz]
Lovely guy, lovely guy. Yes.

[Samuel]
Yeah. He was kind of saying that there’s an argument to say, if you haven’t seal puffed the tooth, then you haven’t filled it completely. I couldn’t really answer for him what he genuinely thinks, but I think he’s got a point on that.

I think overall you don’t want to be smashing loads of obturation and sealing material out the tooth, but a little bit of a mushroom over the end is, is always beautiful to see. I also think that’s another sort of advantage of an x ray is if you’re really, really short, if you’re like 50 millimeters away, you’re never going to get an apex or a portal of exit that’s so far away.

Although I do have cases where, especially on upper threes, where the obturation was a good nine millimeters away from the end, we sent it back to the referring dentist. The root canal didn’t respond very well to treatments. We took a cone beam CT and it just exited. So I suppose what I’m trying to say is you’re going to be using the apex locator and the radiograph in conjunction with each other.

And really what you want to be thinking about is the apex locator is your daddy. That the key. You’re going to be trusting that one person. Essentially, if you don’t know how they work, it just creates an electrical circuit within the body. And I had a little look into this and I suppose, back in the day they used to look at resistance and now the newer ones are looking impedance or the other way around, but essentially you’re just creating that kind of circuit where you’re pushing a metal instrument into the tooth and you want to be touching those, you want to be tickling those periodontal tissues. And they said, that they’re extremely, extremely reliable. You were talking about, should we use a 15 or a 10 to get which hand file to use? I think really, the professors, the people at university, they’re going to say use of size 15, but-

[Jaz]
You know, I was thinking because you want us to be able to see it clearer on the radiograph.

[Samuel]
Well, let’s talk about that. I’m not taking a working length radiograph with a hand file in place. That by personally, there’s no need and our guidance, our FGP, is it FGP?

[Jaz]
FGDP?

[Samuel]
That’s the one. It doesn’t advocate taking a working length radiograph with a hand file in place. It’s now clinically acceptable to take your working length from your apex locator. What it does advocate of course, is that you take a cone fit radiograph just to make sure before you do operate. I think the problem with using a size 15 is that, it’s another concept about taper and and diameter. So personally I use a size 10, because I think that using a size 10, it gives me accurate working lengths, but also it gives me enough, a small enough taper for me to reach the end.

Just think that from a size 10 to a 15 is a 50% jump in diameter and what I would say, though, is sometimes when I get really highly calcified canals, I’ll use a size eight or sometimes even a size six. That’s always a good file to have in your back pocket by the way. I work in many practices and the amount of general dentistry to come in and ask me for a size eight or a size six, I use them.

I use the defined as which are fantastic. They’re like a smooth board sort of file, but say I’m using a size eight and I’m pushing it to length and I get a zero on my apex locator, what I am then going to do is I’m going to use that as a kind of like a gauge because, you say I use a size eight and then I shape the canal, with a size 10 and then maybe with a glide path file, what I’m doing is I am smoothing out the sort of S shape or the other sort of curve shape of the canal, and this is going to shorten the canal.

So not only does a small hand file not give you good enough accurate results, but it’s also when you start to move up the diameters in files, you’re going to straighten out the canal. So say I’m using an eight, I’m going to use that to length, get this kind of sort of estimated working length. I’m going to then shape it and-

[Jaz]
Then using the apex locator with the eight, yeah?

[Samuel]
Yes.

[Jaz]
Let’s say that’s 19. 0. Okay. And you’ve got your reference as well. And then when you move to 10 or maybe it gets 15, you may then shorten, it might be then 18. 5. But at what point do you remeasure? What point do you recalibrate?

[Samuel]
I would like to shape, say I’m using a size eight to what size were you saying?

[Jaz]
19 millimeters. 19. Yeah.

[Samuel]
So I get a glide path file. Again, another thing, if you’re not using glide path files, absolutely amazing. I’m going to shape that to about 18 and then I’m going to go straight back in with my size 10 for sure.

Just to get that. I mean, it happened last week. I measured it and I think it was like 21 and then I shaped it. Not fully to length because I’m worried about the working length. And then when I rechecked it, it was a good millimeter short. And you might think a millimetre is nothing, but on the x ray, a millimetre is a long, long way.

So, another thing what I want to sort of discuss is sort of what kind of makes an apex locator unreliable because I said before that you’re going to use a radiograph and you’re going to use an apex locator in conjunction with each other. I suppose one of the things that’s always mentioned all the time is a canal wetness.

I personally think if you get advice saying if your canals are too wet, that it’s going to give you a poor result. But I think this is overly exaggerated. And in fact, when I’m doing a root canal, I have my access cavity completely filled to the brim with arrogance.

And in fact, when I get a new nurse, she’s going to be one of sucking out. I’m like, no, no, no. I like it. I think the Germans call it a bathtub technique, because I think it’s fantastic. What I would say is though, completely dry canals. That’s going to give you poor readings. Another thing is-

[Jaz]
So, how wet is wet enough then? I mean, do you want a bathtub for the point of using the apex locator? Or do you want to just get the nurse’s suction into it? Or do you want to go paper point dry? How dry do you want to go?

[Samuel]
No, you want it kind of like the meniscus kind of bubbling out, you want it full.

[Jaz]
Okay, so it’s totally cool.

[Samuel]
And the thing with that is it’s going to be like a reservoir for arrogance, isn’t it? And I mean, I don’t know how true this is, but I wasn’t a dentist before. I qualified when I was 30. I was an engineer before this. I did like an engineering apprenticeship.

And I like to think that this reservoir is like a cooling kind of reservoir as well. I would say almost every time I’ve fractured instruments where I’ve just been doing it in a dry canal. And I think this gives it kind of like a cooling effect.

[Jaz]
But you’re not naughty, but just as a quick one, you’re not naughty. If you’re using the apex locator with the hypochlorite like flooding the canal. So what you’re trying to say is okay like, there is a thought I had whereby actually I don’t want it too wet and maybe just a quick dip of the paper point to make it a bit drier not fully dry. But what you’re saying actually is totally okay to have the hypochlorite flooding it. Perfect.

[Samuel]
I think where this comes from is it comes from older generation, apex locators. But the newer generations now, you read that X and all the things, that they’re not interested, but what I would say is that say that you’ve got a metal restoration, you’ve got an amalgam filling, or you’ve got a metal ceramic crown or something that’s going to make that connection is if you’ve got it filled, it’s going to go through that metal. So I would say if you’ve got an amalgam restoration, ideally, you’re going to be pulling that out and then you’re going to create, you’re going to be shoring the tooth up. The great thing about pulling everything, all restorations off the tooth, before you start is you’re just checking the tooth is still restorable.

You’re going to look like a massive fool if you do this gorgeous root canal and you go to restore it and you need to say to the patient, well, I can’t, you know. But there are times when you can’t-

[Jaz]
Like a recent crown, for example.

[Samuel]
Exactly. Like a metal ceramic crown. And also as well, maybe I get in trouble for saying this, but I think if you’re trying to be efficient-

[Jaz]
Just say it. Go for it.

[Samuel]
You’re trying to be quicker. I suppose with NHS dentistry, I did NHS dentistry for a very long time. I actually bought all my own equipments and I bought my own files because I absolutely loved Endo. And I tell you what, my patients were getting a good deal with my root canals and I was taking two hours on them, but sometimes you’ve got that amalgam filling, you know that it’s solid or maybe it’s just been recently placed and you just want to take an access cavity down through that.

And I think me saying that is sacrilege, but I’m just going to say it anyway. So if you’re in that clinical situation, ideally you shouldn’t be, but if you are essentially what you’re going to be doing is you’re not going to be filling the access cavity up when you’re working with your Apex locator. You’re just going to have a look inside the sort of canal space and you’re just going to keep in that all fill up, filled up.

[Jaz]
I just want to highlight something that people’s stories are so powerful, right? And I didn’t know you’re an engineer and you were a dad of three, which is amazing, and then you, I didn’t know you’re an engineer.

And just to learn about your work during your time in NHS Dentistry and how you used to work, buy your own equipment. That’s huge, right? You need to take massive action. Like sometimes you need to grab life by the scruff of the neck and force something to happen. So it’s just, I like to highlight these little moments.

Actually, if you’re in a position where you are not where you want to be, or you made a goal, how are you going to get there? Sometimes you have to do something a little bit out there and start taking more time on your endos and, and buying your own files, which to some associates would blow their minds. Like, wait, why should I buy files? But, you had a higher purpose in mind, so I just wanted to highlight that.

[Samuel]
I’ve got two things to say on this. One of this is, it’s such a cliche. If you love something just lean into it. I absolutely love Endo and you go to work every, I don’t know anybody else who goes to work, wants to go to work and then gets paid a handsome sum for it.

I feel so lucky and I feel like that’s surely a mindset thing and don’t get me wrong, I’ve had times in my dental career where I’ve really, really struggled for sure. Another thing I would say about NHS dentistry is I can tell you now, the hardest thing I ever had to do was was go from NHS to private and not because of anything other than the patients.

I knew my patients so well for so long and they were kind of weirdly enough friends. We used to come in and we used to have a chat and and having that conversation with those people was incredibly difficult.

[Jaz]
How many years into NHS Dentistry did you make a decision to go private?

[Samuel]
Eight years, eight years. So I knew these people for a long, long time. And luckily for me, I could transition these people from another NHS dentist. So we had like a VT who came in and they obviously needed patients. They were being taken on full time. But the thing is what I noticed about a lot of my patients, we got the odd one that was disgusted with it and things.

But that then type of patients, they’re just not happy. They’re happy about everything. But everybody said, good luck. And everybody said, you know what? I know ’cause in the kind of like letter we gave them, it was talking about my endo and things like that. And essentially that’s what I was moving on to.

And yeah, it was tough. And luckily I still work in the same practice as all these people that are there now. And I always say to ’em, I’ll leaving and I say, I’ll still see you. I’ll give you a little wink in the waiting room. And I’ll say, hi. And I do. And they’re sort of sitting there in the waiting room and they’re reading their paper or looking at their phone and I’ll always just go up to them and go, how are you doing and things? And so yeah, that was difficult. That was the hardest thing about going NHS, going private for sure.

[Jaz]
I appreciate you sharing that. These little micro stories are so powerful and so nice to hear. The main reason I asked you about this apex locator and radiograph though, is I just wanted and you’re so good in your channel to emphasize this and you’ve talked about this in various videos is there is a difference between the radiographic apex and the anatomical apex and just because the GP looks short and radiograph it’s a classic mistake as a young dentist I used to look at it oh yeah that one’s short but this is so many of us do this but actually you don’t know the biggest downfall of endodontics is how much judgment is passed on the final radiograph, which actually has, in many cases, no bearing on actually quality treatment, which irrigant was used, was rubber dam used, you learn none of that from a radiograph.

[Samuel]
I had a root canal done when I was 16. And I was in the army, by the way. So I got this done by an army dentist.

[Jaz]
You are so fascinating.

[Samuel]
Yeah. So, my engineering background actually was I worked on, I was tracked vehicles essentially. So it was in tanks.. So I was in an armored regiments and I was a vehicle mechanic and do you know what?

Best, best years of my life. I’ve got friends for life. We still go on these reunions and things. But anyway, I had a root canal done when I was 16, 24 years ago. Now I can’t believe it. And I’m nearly 40 and I look at this root canal and it’s not as great. But it’s there, it works, there’s no apical pathology, no pain.

So I suppose I had an issue with perfectionism early on in my career. If I did 101 good things for the day, and then one wrong thing went wrong, I would focus on that. And it’d be the same with my-

[Jaz]
So many of us do, mate. I mean, you speak to colleagues and we’re all guilty of this.

[Samuel]
It just shows you that you care, for sure. So what I’m trying to say is, you live to fight another day. I think mainly where you got to talk about here is consent. You’ve got to basically start off with the patients and tell them that nothing, one of my first risks I tell to patients is you spend your money, it might look good on the x ray, but it can still fail.

And when most people get that concept, but some people don’t, and then this is where we have the difficult conversation of, is it right for you? Is it not right for you? So I cannot stress how much consent is an issue, but consent is difficult to do efficiently. I’m right.

[Jaz]
Very difficult to do it efficiently. One tip that was taught to me by an endodontist is to, when you have that discussion at the beginning of the appointment, or if you’re lucky at the consultation, if you get to have one for all endodontic reasons is you show them those 3d images. Showing the canal anatomy and how many branches there are.

And you just say, look, this is what we’re up against, right? I can get to this bit, but no one can get here. So we rely on the arrogance and look how complex it is. And actually there might be bugs in there. And just a nice visual to show patience.

[Samuel]
Well, I can go on better than that. I mean, every, everybody laughs at me. All the endodontists laugh at me. I’ve got a whiteboard. I tell you now, if you’re a new dentist, just get a whiteboard, honestly, and a dry marker. And I’ve got a very, very well rehearsed consent process and I will draw their tooth.

[Jaz]
Let’s do it. Have you got whiteboard with you now?

[Samuel]
Do you know what? I don’t rub this out, but let me just-

[Jaz]
So just make sure you describe it for the audio listeners.

[Samuel]
So this is from my endodontic bag and essentially this patient actually had a lower six that had kind of a sort of a calcified kind of root on the distal aspect. So basically we talk about options. I draw the tooth and then-

[Jaz]
You’re literally like talking as you’re drawing, you’re writing out failure.

[Samuel]
I’m like rubbing out the thing. So what I’ll say is see see all this kind of complex apical anatomy here. This will start out as a long kind of root like this and I’ll go, I’ve drawn it long, but actually in real life, it looks like, and I’ll wipe it off and I’ll draw this thing and they go, Oh yeah, yeah, yeah, yeah.

And then I’ll talk about, see how I’ve sort of mushroomed out the sealer here. I’ll talk about this, this kind of sort of arrow here. This is where I’ll say, sometimes we get stuck near to the end and we can’t get to the end. And this might remain bacteria, et cetera, et cetera, et cetera. And then what I’ll always do, and as I’ve just rubbed off the patient’s name here, but I will put the patient’s name here. I’ll put the date, take a picture of it, and it goes on their notes. And golden.

[Jaz]
So we could use this for every scenario, especially cracks, right? Crack teeth and just draw the crack. And if it’s like this, then that’s cool. If it’s like going down into the tooth, then that’s not savable. So that is a top tip right there.

[Samuel]
And the great thing about the whiteboard is you can kind of custom make the consent to the patient. So you say it’s essential you’re going to draw central, aren’t you? Say you’re worried about it having an extra canal, you’re going to draw, say you’re worried about a crack, you’re going to draw a little crack and you’re going to.

But I use it for everything. I use it for crowns. I’m talking about, say the patient I’ve exposed the pulp while haven’t been moving to cage, or an investigation. We’ll talk about all that and I think that’s fantastic. I bought that for 1 99 off Amazon. You know, it’s amazing.

[Jaz]
It’s so, so valuable. It’s not the first time I’ve heard it, but it’s something that is such a great thing.

[Samuel]
And that’s better than consent. That’s my personal opinion.

[Jaz]
Even with the consent forms like wisdom teeth, for example, that’s one time I take consent forms really seriously for obvious reasons. But what even what I’ll do is their exact scenario of their wisdom tooth and the ID canal, I will draw that on the piece of paper, matching the radiograph, and actually talk over it.

And then again, that gets scanned into the notes. The reason why I wanted to get to was because your consent process is so nice. I do think it does help to reduce your complaints and that kind of stuff. But anyway, one more thing before we move on from apex locators is one thing I just want to clarify and you then put the science behind it.

You already talked about how apex locators work, but when you’re using the apex locator and then you get on some of the fancier ones, you see, you’re two millimeters away. You’re one millimeter away. You’re high. And then it goes, beep. I was always taught that the beep is a zero. That’s what you trust. Everything else is arbitrary. It’s random. Just because it says you’re one millimetre away, it doesn’t mean you’re one millimetre away. Has that changed with the newer apex locators or is that still-?

[Samuel]
You know what, I don’t think it hasn’t. But this is a really, really common thing I get with new dentists. You know, they say, oh, I’m a millimetre away. And I just ask the question, I go, well, how do you know you’re a millimetre away? Essentially, these sorts of measurements that you get on your apex locator, they’re arbitrary, so the number is essentially relative to your own apex locator, knowing how far your file is advancing. But what I would say is if you get to know your apex locator really, really well, you get to understand how far you generally are away from this.

So use this sort of relativity to your advantage. I know with my personal one, I use a Wirele-x apex locator. So this is like a little tiny iPads that sits on the side and then I’ve got a wireless. I think that’s fantastic. Cause a lot of the times I’ve got wires coming from the patients and you’re it’s all.

So the YLX is fantastic, but I know on my apex locator, if I’m two bars away. Then I’m about 0. 5 millimeters to travel left. So, I think it’s different for everybody. I think when we’re talking about apex locators, really, there are only two numbers that can be trusted. Okay. The first one is obviously like your x ray is if you’re over.

So, if you push your file through the apex and it’s screaming, you’re out. Another number is the zero reading, although there’s a little bit of a debate here between is the zero reading accurate or not, and what I’ll say is that a lot of the times, I will have my apex locator hooked up to my size 10, for say.

And then I am just sort of, feeling or just tickling down the canal space, and then I reach zero on my apex locator. Now, what I wouldn’t do personally, is I don’t think that’s the zero reading yet. What I like to do, is I just like to push the hand file through the apex until I go over. Now, what I’m not doing is I’m not sort of ramming the ham file down there.

I’m just sort of teasing the periodontal tissues with my ham file. And then once I’m out of the end, I’m going to be in them backing it up. So I’m going to back it up and then when it reaches zero, that is my zero reading.

[Jaz]
Okay. I like that because it just gives you more validation because often what I would do is I would go to zero. I’d hear that zero and then, okay, I’m good. But I like the idea that you go a bit further and then you pull back. And I suppose the logic there is that it gives the apex locator more information?

[Samuel]
Yes. I suppose in a way, what I see in practice clinically is that I will reach zero. And then I can push that hand file, sometimes a millimetre, half. Even further until I have reached over. So there’s that kind of discrepancy there, isn’t there? There’s also another thing to take into consideration with your apex locator zero reading is that you are going to be shaping your master apical file, 0. 5 millimetres away from this reading. So we’re taking into consideration the apical constriction. And this is always sat a little bit uneasy with me because we don’t really know where the constriction is, but that’s-

[Jaz]
Ah, I think that study I quoted earlier being five millimetres away. That’s what I was potentially referring to maybe. That the apical constriction might be several millimetres away from the zero reading. Would that be correct? Was that wrong?

[Samuel]
I think that is to do with the many portals of exit. I think that’s what it is, but I don’t really know. But like I say, with this minus 0. 5, I am shaping my hand files to the zero reading are found on my apex locator. I use glide path files, by the way, if people don’t know what glide path files are. Just get some and you’ll never go back.

[Jaz]
And just on the glide path, like I was taught many years ago that using certain systems that, okay, make sure you try and get like a 15, 20 down first before introducing any files. But really the whole point of glide file is to eliminate those steps. So I think I heard you say that you go from an eight to a glide file. Is that right?

[Samuel]
No, I’d say I’d probably go for an 8 to a 10 to a glide path file.

[Jaz]
Okay.

[Samuel]
You will find endodontists now that have integrated apex locators within their endodontic motors, and they won’t even pick up a hand file, and they will go straight down with a glide path file. Now, I’m not advocating that, especially for our newer dentists, cause that you are flying on the seat of your pants there. But these glide path files are very adept at negotiating, especially I use a Hyflex 1503 personally, I don’t like to do that where I go straight in. I like to have patency with a hand file of I’ve fractured too many instruments to live like that.

But I would say if you’re using a glide path file, you are shape, especially off a molar endo, you’re shaving off half an hour. For sure. I mean, imagine you’ve got three canals, you have to get down to an eight on all three of them. And then you go in there with a 10 and maybe the 15 and it’s just going to take you forever.

And also what I would say with hand files. I think you’re more likely to cause an aortic joint damage with a ledge or a perforation with these hand files. Another thing as well, I bought 600 glide path files because they were on bulk because I knew I was doing molar endo. And this is another thing about, you might think to yourself, well, I’m spending money on things, but actually, you know what, that quickened by treatment time.

And I could just get more patients in on the NHS. And I know it’s not about getting more patients in, but it also just, it’s less heartache the amount of times you’ve been doing with your hand file down, and then you get stuck and you only got to go back down. So if you’re not use glide path files, use them. Fantastic for sure.

[Jaz]
It will save you time. And it’s the way forward. I’m going to give you a little scenario. Let’s say you are 18 millimeters into a canal, you feel a hard stop with your 10, but the apex locator is still not showing a zero. Okay, because I’ve encountered this before, and when we chatted earlier, you made a really great point about binding, which you may want to talk about.

But essentially, what is the cause of that? Because usually, I heard people’s colleagues say years ago that, oh, maybe there’s been some sclerosis, but sclerosis happens higher up and by the pulp, not at the apex area. So if you feel a hard stop, there’s got to be some other anatomical issues there, maybe a ledge or whatever.

So how would you handle that scenario when a colleague is telling you that they’re in with a size 10, they’re feeding a hard stop, they literally cannot go any further. But then the apex locator is still not telling you zero.

[Samuel]
Yeah. So I’ll tell you not what to do straight away is don’t push it even further. And the temptation just to go-

[Jaz]
Oh, it’s so tempting, get a 15 and go.

[Samuel]
And I have done that so many times. Because I will guarantee you will ledge the tooth, you’ll fracture the file. And sometimes say you’re using like a larger rotary file, using a mass apical file, you’re getting a bit stuck.

If you push that rotary file, you will just cause a straight perforation. It’ll just slip through and you’ll know you’ve caused that perforation because you’d be pushing on it and it’ll just slip and it’ll just go in and then you’ll take your working length measurement with your apex locator and it’ll be shorter.

So just don’t push, also say you’ve ledged it. Don’t confirm a ledge by creating, making the ledge worse. Okay. So don’t think to yourself, well, oh, I think I’ve got a ledge there. I’ll tell you what, I’ll just make it a bit more. So I know, I’m sure. So just, just be really, really just gentle and careful. And a better outcome really is to be short. And again, I say that, and there’s a lot of context to that statement. Okay, but don’t be the cause of the problem. Essentially, you just got to read the clinical situation. And I’ll try and expand on that because I know that’s a sort of broad thing.

[Jaz]
I appreciate it’s a very difficult question because there’s going to be about 12 different things going on here. It’s very much the art of troubleshooting endodontics. But just talk about the common scenario that you want a young dentist to appreciate it and when they feel or encounter the scenario. The great tip there is don’t force it, slow down, retract, because you don’t want to make it worse. And that’s a top tip already.

Jaz’s Outro:
Well, there you have it guys. I left you on bit of a cliff hanger. What will Samuel recommend you do when your file is getting stuck? It’s not an easy question, but he does a wonderful job, so tune in to part two of this episode to find out how to handle that scenario.

Also in part two, we cover something called file gripping. When you’re trying to go to length, but your file is not going, it’s often not to do with the tip. It could be a problem higher up. And then we take loads of questions from the Protrusive Guidance community. You guys had some wonderful questions, so I asked a whole bunch of those questions from you guys. For example, a lot of biological dentists are claiming that root canals are bad and patients are therefore not wanting root canals or wanting to have extractions of their perfectly sound root canals.

What does Samuel think about this cohort of dentists, these biological dentists and these patients? And how important is ultrasonic activation of the and a whole bunch of other amazing questions that you guys asked. So claim the CPD for this one below if you’re on the Protrusive Guidance app, but you must tune into part two for more endo goodness and a whole bunch of question answers thanks to you guys.

Don’t forget to hit subscribe and like and check out Sam’s wonderful channel as well. I’ll catch you same time, same place next week. Bye for now.