High-Frequency Healing: Revolutionizing Endodontic Disinfection

This is the only irrigation device that we have today that allows you also to go long, which means that you not only shock the inside of the canal, but you can also shock the lesion itself. So one of the reasons why this particular system promotes faster healing is that you're not only sterilizing the inside of the canal, but you can also go long and shock the lesion on the outside, which allows for faster healing. Welcome to the Phil Klein Dental Podcast. All of us who are doing endo in our practices have one main goal in mind, and that's to save the tooth. And we know that the most important thing we can do in our root canal cases in order to achieve high clinical success is to remove all the tissue and disinfect the root canal system. But in many cases, it's impossible to reach lateral accessory and small constricted canals with our disinfectant irrigant, such as sodium hypochlorite. This means we often leave active microbes in these areas that can eventually lead to an endodontic failure. So the question is, is there something we can do in our procedure that can solve this problem? The answer is yes. It has to do with a new technology that is relatively inexpensive and very easy to use. This technology is based on high-frequency conduction, and it is extremely effective in helping to disinfect tiny accessory canals that would otherwise go untreated. And I do want to mention that this technology that's been introduced by J. Morita does not include disinfection as part of its FDA approval. So using it to disinfect is the opinion of the speaker, not J. Morita. To tell us all about it is our guest, Dr. Bruno Azevedo. Dr. Azevedo is a board-certified oral and maxillofacial radiologist, endodontist, and arguably the best teacher and educator on the topic of CBCT in dentistry. His systematic approach covering the six pillars of imaging has helped thousands of practitioners in over 20 countries get the most out of CBCT. Dr. Azevedo, thanks for joining our show. Bill, always a pleasure talking to you. This is a really important topic, not only for specialists, but also for general dentists who are doing root canal in their GP practice. There's a challenge that we all have, especially with the molars, when we get into those multi-rooted teeth. The primary challenges we have, list those out for us when it comes to achieving complete root canal disinfection, because disinfection, of course, is an important phase of root canal therapy. What do we face as clinicians? as our primary challenges to complete that task? So, Phil, when we're talking about root canals, and that can be from an interior tooth to a molar, we know that the biggest challenge that we have is to always to disinfect the apical third of that tooth. And the reason for that is when we are talking about root canals, we're talking about a system. We're talking about not only the main canal, but also a series of very intricate... anatomy that is associated with them. That can be lateral canals, that can be accessory canals. And unfortunately, those guys can be really, really tiny, you know, sometimes in the neighborhood of 50 microns, 40 microns, and can have, you know, different branches with different angulations. And we know that our fire systems, they do not penetrate those branches and those lateral canals, depending on the angle that they're in. Unfortunately, because of the instrumentation that's done, when you are trying to achieve patency, for example, there can be lots of debris that can block our irrigant solutions from reaching out to inside those microanatomies. And unfortunately, we can leave bacteria behind. So, you know, as we... tough cases, we know that there is a heavy bacterial load at that apical third. And different than most people believe, the fire is not really doing anything. The fire is not really killing bacteria. What kills bacteria, it's going to be our irrigant solutions. So every time that we perform root canal therapy, what we're really trying to do is wage chemical warfare to the apical aspect of that tooth, right? But unfortunately, the law of physics are against us. And one of the main reasons that sometimes we cannot irrigate the apical third based, you know, the way we want it to, it's because of a phenomenon called vapor lock, which is the fact that a tiny little bubble can form at the apical aspect of the tooth. And no matter, you know, how much force you use trying to get irrigants down there, you know, that tiny little micro bubble. is enough to prevent some of those irrigant solutions to reach some of those microanatomy areas. And then therefore, the root canal is not going to be as good as we think it is. So Dr. Azevedo, as we've all learned in dental school, and this was obviously emphasized in my endodontic program when I went to school, removal of the tissue from the root canal system is critical. That's the key. Get everything out, clean it out really well, and get the disinfectant solution as far into the canal system as possible. And even doing so, there's a difference between the success rate of treating vital teeth versus necrotic teeth, non-vital teeth. And this makes sense because if you leave tissue behind, the tissue that's left behind in the necrotic cases are likely colonizing microbes that are causing or perpetuating the infection. So address that issue because it does relate very much to the technology that we're going to be talking about today. where the goal is to get into those lateral and accessory canals so we can disinfect them. When you think about the techniques being used on a tooth that was vital versus a tooth that has AP, technically speaking, they should have exactly the same success rate because the technique that we're using is the same. However, what we do know is that teeth with AP... Particularly when we employ now home BNCT imaging as a method to evaluate long-term follow-up on those teeth, they typically range in the neighborhood of 85 to 90 percent. where teeth without AP range in the neighborhood of mid-90s, about 96%, 94%. Yeah, and AP, just to clarify for our audience, apical periodontitis. Apical periodontitis, sure. So any tooth that has apical periodontitis, has a lesion associated to it, has less likely of a chance of healing than something that is just a hot tooth that's a vital tooth. Right. And the difference of that has to do with microbes. So any tooth that has an apical lesion, AP, has microbes inside that tooth. So when we are now talking about can we cure microbes as we can, differently than the old days of endo, we are now trying to be more minimally based, meaning that we're trying to instrument teeth to smaller shapes to allow more dental structure to remain behind so we can get more function out of those teeth and of course avoid vertical fractures in the future, for example. So we are trying to keep those shapes smaller, particularly because, you know, we have different obturation materials. We have bioceramics now and single cone technique and all those things. So the idea is we are trying to irrigate a tooth or sterilize the tooth as much, the best that we can without having to remove a lot of denting. And you're absolutely right. The success of the root canal in the end of the day is not going to be associated with what you put in, but what you take out. The most important thing is I have to take out as much bacteria as I can possibly can, right? So I don't... anything leaking towards that PDL space, creating an inflammatory reaction that can lead to pain or inflammation and then to lesions and things of that nature. So anybody that's doing endo out there, just remember this. Every time that you put in a file inside a tooth, you're not killing bacteria. You're creating a pathway for the chemicals that we use, particularly sodium hypovirate, to go in there, do its job, and kill bacteria. The challenge also that we currently have is that unfortunately, because of the microanatomy, because of debris, sometimes you can get blockage of those microanatomies. And then no matter how much we try, we cannot get those liquids, right? Our irrigates within those microanatomical structures and bacteria stays there. Right. And that's where my next question comes in, Dr. Azevedo, so that your prelude to that is perfect. There's a new technology out. called High Frequency Conduction, HFC, that was designed specifically to address the issue you just explained, which was difficult access to areas down in the apical third of the root system because of what you said, a blockage or a bubble or whatever. So now we have this new high frequency conduction that's been introduced by Jay Morita that snaps onto the root ZX3 apex locator. So really phenomenal stuff. Tell us the latest on this and how this helps us go beyond what we typically would have access to with traditional methods of irrigation. So I'm going to backtrack here. I want to tell you actually my history with this particular technology. The first time I saw this was in 2019. I was walking around the AAE, the American Association of Endodontists meeting. There was a poster from a Japanese student showing some crazy healing on some really large lesions. And the only thing that it was saying was high frequency conduction was used. There was no explanation of what it was or what it looked like. And at that time, I was talking to the VP of Morita. And I was asking him, I was like, listen, I just saw this poster and I want to understand what that was. What is this high frequency conduction thing? And he literally just shushed me off and said, shh, company secret. Basically, that's what happened. So I had this in the back of my mind for forever. And I was like, man, I know they're cooking something. I just don't know what it was. So back in 2023, I saw that they finally release. The new RootZX. So for those who don't know, RootZX is an Apex locator. It's probably considered the gold standard of Apex locators in anodontics. And the new RootZX3 had the HFC module. So the secret came out of the bag. So immediately I contacted Japan and I was like, listen, I really wanted to test this technology. Can you send me a unit for testing? Let's see what this does. So after a lot of back and forth negotiation that took about six months, I actually got the first unit in the United States. And it looks like an apex locator. It is an apex locator per se. Everybody that does root canals, you're using an apex locator in any given time to check your working lens, to see where you are, and uses that procedure to now enhance the root canal treatment by discharging an electric pulse. inside the root canal that can disrupt bacteria and kill bacteria. So basically, what is high-frequency conduction or electromagnetic apical treatment? It's the ability to place a file inside the canal with irrigants. And as you activate the unit, it's going to discharge electricity, about 500 kilohertz of an electrical pulse at the apical aspect of the tooth. That electricity... generates a spark, right? Almost imagine like a lightning inside the canal. And that energy gets transferred throughout the whole canal system, regardless of there is a blockage or not, because dentin is really good in conducting electricity and also heat. As this electricity and heat gets dissipated, it increases the temperature inside the root canal system, particularly in the areas where you have microanatomy. the microanatomy, the smaller the branches around the main canal, the more heat is generated. And that heat is enough to pretty much obliterate any type of tissue inside those canals. Now, when this HFC technology is introduced into the canal, it's done through a typical file. Is there any special file that needs to be used? Or you can use a NITI file, for instance. So it's used through a special file called an electrode file, which is a number 10K file with a special coating that covers pretty much about 90% of the file. Only the last apical three millimeters of the file are not cold. So what that means is it allows for the distribution of that electricity to flow all the way to the apex of the tooth. So again, it comes with this file. It has different numbers, so you can have a 10, a 15, a 20, or a 25K file with the special coating. And again, the name is Electrode File. How long does the high-frequency conduction need to be applied through that file in the canal? Is it a short burst of energy, or what's that process like? That's a great question. So it is a really short burst of energy. So as you go along and you're trying to achieve your patency with your file, typically, you're going to be following your apex locator until you hit that green light. When you hit that green light, that's typically when you're going to shoot the HFC. You're going to do about three shots per canal. Each shot lasts less than a second. And in between shots, you just have to wait three seconds. So as I place my file down, and it's where I want to shoot, I press a paddle, and it really shoots in about a second or so. And then you remove the file, put more liquid in the canal, maybe some more irrigation, like storage up to the right. Place the file back again to the desired position. One more time, one more step. Literally, it's one second. It's one beep, and that's it. it's done. So you're essentially cauterizing the tissue that is in those canals that are basically inaccessible. Now, you mentioned apical periodontitis. Now, in those cases, that tissue is already necrotic. So what happens to the actual dead tissue that's in there? And how close do you have to be to it for that burst of energy to actually ablate the tissue? So interesting enough, If you're dealing with a necrotic case, okay, what we know now is that anything within a millimeter or so of the burst gets to be cauterized within the first shot. After you do your second shot, anything within two millimeters of that burst can now be completely ablated or cauterized, regardless if this is vital tissue or necrotic tissue. And this is the good part of it. Interesting enough. This is the only irrigation device that we have today that allows you also to go long, which means that you not only shock the inside of the canal, but you can also shock the lesion itself. So one of the reasons why this particular system promotes faster healing is that... not only sterilizing the inside of the canal, but you can also go long and shock the lesion on the outside. And that actually creates a better anti-inflammatory response, which allows for faster healing. So is there any case selectivity when using this HFC module? In other words, should it also be used on a vital case? There's no periapical lesion. Pretty straightforward. Or is this something you would prefer to use on every case to play it safe? I would use this on every case. The only time that we are not going to use this is if the root, it's actually on top of the Mindyabue canal. That would be the only time that we do not advise the use of the high frequency conduction. But if you have a vital tooth or a non-vital tooth, I'm going to use this all the time. But interestingly enough, Phil, One thing about this particular technology is that there are multiple applications for it. They're just not the irrigation part or not the sterilization part of the tooth. This can also be used for anesthesia. So as we know, one of the challenges that we have when performing root canals, particularly in the situation that you just described, which is to have, let's say, a hot tooth, a hot number 19, is that From time to time, you know, we have to use and employ the use of, let's say, an intrapulpal anesthesia. And it's not uncommon for us to start, let's say, debriding the tooth, start instrumenting the cervical third of that tooth, and the patient still feels the action. So in this particular case, you can use the high-frequency conduction and shock the pulp in order to completely anesthetize it. So you can complete the root canal with the patient being very comfortable and pain-free. How much area does that cover in the pulp chamber? Because a number 19 pulp chamber could be pretty, lots of tissue in there, and that's a pretty fine tip. So what are we looking at as far as coverage with that conduction? So the cases that I've done, basically, I never had to use more than three shots per tooth. So the first shot pretty much... of uh kind of allows you now to work within the poke chamber no problem and if there's any remnants inside the canals themselves the moment that the patient feels it you know as you know this is an endodontist so as you as you start to file a canal sometimes the patient will say oh i feel that so all you've got to do is stop push the pedal and you're done patient may feel that little shock you know like like they normally would but after that it's pretty much pain-free so I didn't believe this until my first case. And it was very, very interesting to me to see, you know, a hot tooth, a mess there. The patient is, of course, is in a lot of pain. And the moment that that file touched that canal, you know, it was a mesial buccal canal on the number 19. My patient was, you know, in a lot of pain, a lot of discomfort. I just told him, just bear here with me for half a second. use the high frequency conduction, you know, the patient gets that at least of shock. And then I just told him, okay, let's see what happens now. I was able to get the patency, absolutely no problem. The patient was super happy at the end of the day. So when you compare an intrapulpal injection, Dr. Azevedo, to using an HFC module burst of energy for the same purpose, which is to cause anesthesia or numbness in that area, how does the sensation differ? Is it... less of a sting with the electromagnetic burst, or is it very similar to the intrapulpal injection? It's a discomfort to the patient. I wouldn't call it painful where the patient jumps out of the chair or anything like that. They will feel it, and you can tell them, listen, you may feel some sort of discomfort here, but it will last less than a second. It's going to be similar, but without the trauma of the needle. Or, you know, I think you have more control with the file, trying to find it, you know, getting inside the tooth. And sometimes the beauty of it, because it's a file, you know, you're not binding that, you know, that file to any walls or anything like that. You're just literally going down. And the patient tells you right away, it's like, you know, just by the body language, this is where it hurts. Okay. So you feel it, that they do that little jump, little jump scare, and that's it. It's done. From that point on, you can go back and finish your root canal with no problems whatsoever. At least my experience on this has been very, very positive. So talking about the actual device itself, the HFC module snaps on rather quickly to the root ZX3 apex locator. And that's by Jay Morita. I assume that that module, that HFC module that creates that energy that gets transferred down to that file to accomplish all this is unique just to the... Marita Apex locator can't be used interchangeably with another Apex locator. I assume that's the case. That is correct. So the RootZX3 can be used just as an Apex locator. But if you wish to have the high-frequency conduction, you can remove the battery pack from the Apex locator and attach the high-frequency conduction module. The high frequency conduction module will come with different components. One is going to come with, you know, your lip clip, which is a much wider lip clip than normally used for the apex locator's purposes. Then you're going to have a counter grip attached, and that is a metal cylinder that the patient must hold in their hand as you're using the high frequency conduction. And of course, you're going to need to have that foot switch. in order to be able to activate the high -frequency conduction module as you wish throughout the root canal procedure. Interesting enough, the high-frequency conduction also comes with a holder for a cheap electrode, which can be used as an electric scalpel for gingival tissue removal, for example, and incisions. So it has Basically, this module has three functions. You know, we can use it for irrigation purposes, like we were describing. We can use it for calterization purposes and controlling of bleeding. We can use for anesthesia. And we can also use it as an electrical scalpel to kind of cut digital tissue around the tube, for example. If you have to do like a distal margin elevation, you can kind of cauterize the tissue there with this. So I've been talking to many dentists, GPs on this podcast program, some of whom have moved to remote areas. And one of the challenges moving to a remote area, and there's many advantages, but one of the challenges is finding a specialist that's close by. So when they come up against a difficult molar, which they would normally send out before they moved where they are now, They can't do that as readily because the nearest endodontist could be 100 miles away. So one of these dentists purchased an Erbium YAG laser, and he found that using that laser, which was a lot of money, I think it's $100,000 or something he spent, creates this cavitation or turbulence that sounds like it's doing what this HFC module is doing. But of course, the HFC module is a whole lot less money. So tell us the difference between using something like an Erbium YAG laser versus this hfc module because one is a hell of a lot cheaper than the other so this is a great question what you're asking me and it's coming from somebody that's also a laser user So there are things that the laser can do doing root canal therapy that this cannot do. For example, laser can actually help you through laser cavitation achieve patency and kind of create cavitation with it. This guy is not going to create cavitation. This guy is going to bypass the cavitation and sterilize whatever is beyond. So I think when they, you know, this is kind of like how I work. I actually work with both. And it's awesome. But in the absence of advanced irrigation, this is definitely the next best thing. So give us an example, Dr. Azevedo, clinically on when you'd pick up that Erbium YAG laser and then how you would use the HFC module. So imagine this, as I'm doing a root canal, right? Our goal is to get as close as we can to patency or to patency. Sometimes mid-root, you can get blocked. So for all kinds of reasons, you can get blocked just at a mid-root. It can be a calcification. It just can be one of those really tough root canals. So typically with a laser, I can just go in there and activate the laser with some EDTA, with some hypo. And the cavitation power of the laser can remove that blockage from me. So now I can drop a number A file and get to patency and create the glide path that I need to, again, to keep irrigating, irrigating, irrigating. With this particular system, I wouldn't necessarily be able to remove any blockages mid-root, for example. But if I can get to the apical aspect of the tooth, this is now, in my opinion, probably the best tool that we have available to try to sterilize and kill as much bacteria as we can because where all the other systems fail, which is, you know, trying to get irrigants into very tiny little spaces that are going in crazy angles, you know, that is associated with the apex of this tooth, this is where it shines because it's not only... the irrigants there with that spark, but it's also creating heat and distributing electricity. So you have basically three things acting in your favor here. You have the irrigant solution, you have heat, and you also have electricity. So the combination of those three are very powerful and definitely enhance the success rate. So where would you not use this HFC module? Do you need it in a number eight or nine where you have a wide open canal, really straightforward case? Are there any contraindications to using this? You know, so interesting enough, and this has to do with my work with combing, you'd be surprised by how much anatomy a central incisor can have, okay, at the apical aspect. So at this stage, as long as the apical aspect of this tooth, It's not in contact with the nerve. I will use it on every case, on every scenario, vital or non-vital, 100% of the time. So 100% of the time, unless that root is sitting on top of the mandibular nerve. That is correct. And here's the beautiful part, Phil. This technology does not require extra time. So what is the idea here? What do I mean by that? So if you were using a laser, for example or other units that are out there for the disinfection of the canal system it requires extra time you know you have to budget extra time to use the laser 30 seconds for the canal multiple times and so on this guy takes one second and it's and it's and you're using this as an apex locator which you already budget time for it anyways so the idea here is you not only save time by by using this device You use it on every single case. So it's a no-brainer to be using this. The cost of use, it's minimal, if any. And, you know, it's going to be to the best study that's being done now that was published this year on this particular case. It also justifies the use on every case. It has to do with post-operative pain. So they did a research in Japan. where they did 2,000 root canals with the same provider with high -frequency conduction and 2,000 root canals without high-frequency conductions. The reduction in post-op pain on the sample that high-frequency conduction was used was 95%. So 95% less post-op pain than the control group. And these were vital and non-vital teeth mixed together? Correct. 2,000 cases of all sorts of nature. They were not separated by just this or just that. It was just, this guy got HFC, this guy did not. And they recorded an over 90% reduction in post-operative. Is that post-operative sensitivity that occurs directly after the root canal? That is correct. Okay. So, yeah, that's an interesting study because, you know, over-instrumentation could cause post-operative sensitivity. I mean, there's a lot of reasons why there could be post-operative sensitivity, but you're saying this high-frequency conduction is doing something based on these statistics that's eliminating, in many cases, post-op sensitivity. So there's something going on that it's doing on the neurological level that's keeping that patient more comfortable. Correct. That is correct. Did the researchers that did the study suggest a mechanism for their findings? So what they were talking about is that the high frequency conduction promotes an anti -inflammatory reaction at the apex of the tooth that is the cause for this. So that's where the studies are pointing to. They don't know exactly how to explain the why. But there is an anti -inflammatory reaction now that is associated with the use of electricity inside the tooth that it's promoting the faster healing of apical lesions all the way to better comfort. So what we do know is just like I was explaining to you from the anesthesia perspective, this guy, it really is almost like frying the nerve inside the tooth pretty much. I don't want to use this. Right. It's cauterizing it. Cauterizing, yeah. And that wasn't the reasons why it's been so effective. I don't know if you have a way to leave this article available for those listeners. Yeah, we'll put it in the show notes. We'll put it in the show notes. But I'll be happy to send you the link or the article itself. So for anybody that's interested. in understanding a little bit more about high frequency conduction in this particular study that I was quoting, they will be able to read from themselves. Interestingly enough, this study was actually conducted by the inventor of the high frequency conduction, which is Dr. Tobin Agua from Japan. As we wrap up this podcast episode, Dr. Azevedo, any closing remarks, any thoughts to share with our audience? For those who are interested in learning about this, you can always go to the Merida site. There's a lot of good information there. And just remember, this is an apex locator that has a module that can be used for irrigation, culturization. You can control bleeding inside the tooth. This is something that's important to stress because sometimes when you're doing root canals, you do get bleeders, things that are just hard to control. This can definitely help with that. And again, I've been working with this technology now for about a year. My results have been great. I never had any problems with any patients complaining of the use of this inside the root canal system. Yeah, I'm excited to see more colleagues around the world and here in the U.S. using this. You know, if anybody has any questions or want to know a little bit more, you can always shoot me an email at Bruno at ConeBeamGuy.com. Again, Dr. Azevedo's email is Bruno, B-R-U-N-O, at ConeBeamGuy.com. That's ConeBeamGuy.com. Dr. Azevedo, great stuff. Love having you on the show. Thank you so much. Cheers.