Reaching the Unreachable: Killing Microbes in Lateral and Accessory Canals

And so it sends electrical current that increases the temperature inside the root canal system. When used in irrigation, it causes the pulpal tissue and the bacterial debris to be cauterized or decomposed. And so it helps us to yield a cleaner canal, especially in the apical third and especially in areas that are difficult or hard to reach, such as lateral and accessory canals. Welcome to the Phil Kline Dental Podcast. When performing root canal procedures, our goal as clinicians is to thoroughly clean the root canal system, disinfect it, and seal it to prevent microbial infection. But when dealing with complex cases, this is easier said than done. Tiny accessory canals and curved canals can make it challenging to properly instrument and irrigate these areas. But what if there were a simple way to deliver an electronic charge into these difficult-to-reach spaces, cauterizing soft tissue and making it easier to flush out? By doing so, we could effectively eliminate microbes hiding in constricted lateral and accessory canals. The good news is, with the introduction of a new technology by Jay Merida called the HFC module, we can do just that. This innovative device seamlessly integrates with the root ZX3 apex locator, requiring no additional time or space, yet offering a major breakthrough in root canal therapy. Joining us today to discuss this game-changing technology is Dr. Chafic Safi. Dr. Safi completed his postgraduate residency in endodontics at the University of Pennsylvania in 2015, where he also earned a Master's of Science in Oral Biology. He's a published researcher and international lecturer on various endodontic topics. Dr. Safi remains on faculty at both the University of Pennsylvania's Department of Endodontics and the University of Montreal as an adjunct professor. He's also a faculty lecturer for Next Level Endodontics. currently lives in practices in Montreal, Canada. Before we begin, just a little housekeeping disclaimer. Anything discussed on this podcast are the opinions of our guest and myself, and not necessarily the opinions of Jay Merida. And by the way, if you're enjoying these episodes and would like to support the show, make sure you're following us on Apple Podcasts and Spotify. I really do appreciate it. Dr. Safi, thanks for joining us. Thanks, Dr. Klein. It's my pleasure. So it's certainly interesting that we both are alumni of the same school. University of Pennsylvania School of Dental Medicine, Endodontics. And that certainly should make this discussion a lot of fun. So to begin this podcast episode, Dr. Safi, before we get into the details of the high-frequency conduction module that we're going to be talking about today, give us an overall background on what our goals are when we do a root canal procedure, talking about instrumentation, irrigation, and obturation. So if you go back to the basic of endodontics, the goal of any root canal treatment or retreatment if a surgical, if an endodontic case failed, is to gain microbial control. And to gain microbial control, we need to instrument mechanically, clean chemically with our arrogance. And of course, at the end, obturate in order to kind of seal this microbially controlled state, freeze it in time. We know that each of those steps, especially instrumentation and irrigation, we encounter a lot of challenges when it comes to these steps. And whether we as endodontists or general practitioners, it's really to master the apical third to get the debris out, of course, in a minimally invasive manner as well, meaning to be able to conserve or to save dentin in order to, of course, offer some kind of solidity to the tooth so it doesn't have the risk to crash. or to break on the long run. And so this has been always a challenge to clean and to remove as many as bugs as possible or to prevent their colonization of the root canal system in a minimally invasive, conservative manner. And this is where in the last 10 years or so, a lot of focus has been done, whether in terms of obturation, instrumentation, and of course these days in terms of irrigation. Yeah, and I think you summed that up very well. It's a far cry. from what we were taught in endo school back in the day where we were judged radiographically by how large we opened up the root canal and the the thicker your gutta percha and the brighter the brighter and more opaque it is the better endodontist you were i mean that's how it was and i was like i i wasn't a big fan of that i thought it was you know crazy to bring these roots up to certain numbers on the k-file scale at that time we didn't have you know the rotary yeah we didn't even have rotary but you know that's how you were judged you would do your presentations in front of your classmates in front of your colleagues and they would look at how big your canal was and and uh you know i was kind of um i don't know if i was ostracized or whatever but yeah i was looked upon as kind of uh not following the routine of what was going on in the class. We had eight people in our program. There were some people that supported me that said, this is lunacy opening these canals this wide. So now that we've all come to our senses, and thank God we have, we're more conservative. We're conserving tooth structure that's so valuable to the strength of the tooth. But there's a game changer that's out there. And Jay Morita came up with this. really brilliant concept, which I'd love you to talk about today, called high frequency conduction. And that is accomplishing things in a way where we can actually disinfect the canal through this very unique system, tool, without obliterating the canal by over-instrumenting it. So tell us about that. correct so the the high frequency uh conduction is is is a concept that's based on on yielding or on generating a very strong frequency electric conduct conduction all the way through the dentin inside the canal in order to get some therapeutic effect. And this has been used, for example, in medicine for a very long time, in many examples. And now we're able to adapt it into our root canal system. And so what's happening is that J. Morita came with this new apex locator, the RootDX3, the third generation. And with it... comes a small module or a small component that gets attached behind it and this module works by sending a shockwave if you want of a certain frequency when it's attached to a certain high frequency file that comes with it And so it sends or it generates, it dissipates, it distributes an electrical current that increases also the temperature inside the root canal system. And it causes many things, namely, when used in irrigation, it causes the pulpal tissue and the bacterial debris to be cauterized or decomposed. And so it helps us to yield a cleaner canal, especially in the apical third. And especially in areas that are difficult or hard to reach, such as lateral and accessory canals. By creating this electrical current, it kind of sounds like a shock wave increases the temperature of the irrigant for about a second. I mean, we're not talking about like a duration of temperature that's very high in order to, of course, avoid doing more damage to the periodontal tissues and the surrounding periodicular tissues. combination of electrical current and heat disrupts, if you want, any bacteria or pulpal debris and creates a cleaner canal. This has been also used to help us to control hemostasis in certain example, cauterize gingival tissue, and also in anesthesia. to that probably during our discussion when we explore more benefits of the HFC. So from the standpoint of clinical protocol, when you use this, the HFC module, which again stands for high frequency conduction, snaps onto the apex locator that J. Morita sells. And it comes with a file that's specific for this that conducts electricity. And we know Denton is a good conductor of electricity. So it carries this electrical charge into the apical part of the root canal system. And let's say we're working with a non-vital tooth. So we have necrotic tissue and very small terminal canals. They're lateral canals. Nobody's going to be able to instrument in there. And we won't even be able to get sodium hypochlorite in there necessarily. So when you do this electrical shock, it sends the current through and it heats up the tissue. This necrotic tissue, does it ablate where it's gone, vaporizes? Like you said, it's cleaning the canal. So what it does, that current creates like a spark. at the file. So as you said, it comes with a module and there's certain conducting files that are placed, let's say, in a necrotic case to the working gland and attached to the modules. And then there's a foot pedal, one of the components, like a foot switch, if you want, that you push on that pedal. It creates a certain current that lasts about a second. During that second, there's like an energy transfer from the tip of the file. And what it does is that it decomposes. It's kind of, if you want, silverizes or cauterizes the tissue and the debris inside those accessory canals. So if there was something you could imagine that it's making it very soluble or it's making it even like very in small particles that you can after that come with your irrigation sodium hypochlorite and flush everything everything out in order to get it to a cleaner state. One of the biggest advantage actually when we're talking about irrigation and using the HFC is that it's the only tool or the only instrument that today allows us to even have a certain reaction beyond the apex. And most importantly, in cases where we have apical crescentitis, or in other words, when we have an apical lesion. So in those necrotic cases where we have apical disease, when we approach our conducting file, which is that file that comes with the HFC, and we approach it to the apical terminus, let's say to working gland, or let's say to the apex itself, it's been shown that that current... can can travel for about a millimeter of a radius if you want let's say that the radius of action beyond the the apical foramen and cause in a favorable immune response, meaning elicit the good immune cells in order to bolster or to promote faster healing of the apical lesion. This, of course, with the cleaning of inside of the apical tissue, of the apical ramifications, is a new, if you want, advantage that nobody was able before to be able to conceive in a small machine that is... easy to use and and and to to incorporate in the dental practice so this is the first time in endodontics that i know of where we actually get an advantage of going having something happen beyond the apical foramen right because normally that's the last place you want to go when you're doing endodontics everything is you know you don't want to overfill you don't want to over instrument so you're saying that there's some biologic activity some stimulation that's going on from the electricity that's being generated from the high-frequency conduction unit, and it's stimulating some healing process in an area of rarefaction where there is bone loss. 100%. So we think that it elicits like an anti-inflammation reaction. So it kind of slows down the inflammation process of apical periodontitis. You know, the real research for that is still being investigated. So what we know is that... It creates a favorable environment and it calls for the immune cells in order to start the elimination of the apical disease and to deposit bone and PDL to reconstruct the lost architecture. So it's a positive, if you want, favorable reaction. What I have to mention is that the conducting file is not... The concept is not to push it out of the apex, but to get to the apex, of course, confirmed on the root DX and or on the x-ray. And then at that level to generate the impulse, to generate the shock wave. And that shock wave can travel for about a millimeter around itself and then elicit this positive immune response that we were talking about. So let me ask you this. So one of the things I like about this system very much is that it doesn't take any extra time because... You know, everybody should be using an apex locator at this point if you're doing root canal, right? I mean, that's something that these are so advanced and they're so accurate. And they have readouts that give you information that's just invaluable while you're doing your clinical work. So in the case of using this module that snaps onto this apex locator, tell us the clinical... procedure of when to actually step on that pedal like let's give us an example let's say we're doing number 19 and we're working in the the distal root of number 19. So let's say we have a number 19, a distal root. To start with, we're going to start with the basic case. Let's say it's a vital case. Okay, so we're not looking at any bacteria or any debris, but we have, let's say, pulpal tissue, and we're trying to get that pulpal tissue out as much as possible in order to control the environment. After, let's say, finding the working gland of that distal canal and... creating a certain space that could accommodate the high frequency file in question. So the high frequency files, they come in multiple sizes. So it's equivalent to either a number 10K file, 15K file, 20K file, and 25K file. And of course, it's made in order to fit inside the canal in question. So let's say we have a canal that's the first file that we use as a size 10. After finding the working length, we could instrument that canal with a size 10 or 15 hand file. Then we could put that high-frequency file inside that canal. And in a vital case, It's not recommended to get very close to the apical third in order to avoid causing a lot of damage to the surrounding natural tissues that are unharmed because there's no disease. So it's recommended to go, let's say, about one millimeter close to the working length. And then we push on the pedal with our foot. It generates the... the electrical current in order to help us to dislodge any like spalpel tissue and to kind of cauterize it which will make it easier for us to to irrigate it in a case where it's a vite it's a necrotic case and we have a periapical lesion then we can get this hash high frequency file a bit closer to the working gland which is or the working gland itself and create that high conduction uh electrical current in order to really get and dislodge all the material and get the accessory apic canals cleaner and have a favorable response in the area where the lesion is as well. So when you're using the HFC module with a special file that comes with the system, there's a foot pedal that you depress. And when you step on it, it creates a one second shock. Is that right? Yeah. So it creates a one second shock and it's recommended to wait at least once. second before sending another shock and not to do more than three shocks in the same area because we have to remember that there's also an increase in temperature inside the root canal system. So we don't want to increase that temperature above a certain level in order to avoid any unwanted damage to the surrounding tissue. So one push on the rheostat gives a shock of one second. and if you deem it that you would like it a bit more to to find a more effect or you want the canal to be a bit more cleaner at that same level wait one second between each shock what's important also to mention here is that every time we solicitate this tool or the high frequency at the same level we get a surface or a certain surrounding of the canal that is cleaner that area that's cleaner will help the next electrical current get propagate it a bit further away because there's less debris and less material in there especially if we irrigate between the two electrical shocks so which so in other words we're doing like like a cleaning by by layer if you want or by by by millimeter to to yield a cleaner canal right but we're really focusing on the apical third of course so when you do that first shock you can essentially take the instrument out, go back in there with a syringe and irrigate, and then use your rotary instrumentation to continue to file that area with the sodium hypochlorite, for instance, as your irrigant. Of course. And then, of course, you can repeat that process, but it's important to have that sodium hypochlorite irrigant in the canal system when you use this HFC module. Yeah, we have to have sodium hypochlorite in there because sodium hypochlorite also will conduct the heat as well in order to really have that positive effect. And we have to have some sort of irrigant in there. We shouldn't just use that high-frequency file alone. It has to be in the irrigant, which is sodium hypochlorite in what's used most of the cases. Okay, so in the example of a distal root of number 19, three times is all you want to do. You don't want to do more than that. We don't want to do more than that three times, especially at the same spot. You can do it at different spots. So let's say, for example, in a case where you're looking at a certain side of a canal under the microscope or under your loops, and you see that there's some kind of pulpal tissue or debris stuck on there, and you're trying to get it out. You take your hand file or like you take an instrument, you try to scrape it out and you're not able to scrape it out. So if you can measure around, let's say, to what the depth of that debris that's stuck on the canal wall, you could adapt that length to your high frequency file. And then you could navigate with that file to that level and then shock that area three times, each time giving yourself one second of a break, but not more than three, not to overheat that special part. And this will get that debris or that sometimes even in the retreatment, if you have got a percha that is stubborn in there, that is stuck or a bit of sealer or something that you want to get it out. It also helps to disintegrate or to get it this large and get it out when you irrigate it. And it should be pointed out that the cost of this is very reasonable for a few thousand dollars. I don't know if it's two or three thousand dollars for the unit. When you compare that to the cost of a laser, now that's a different. mechanism. It works on cavitation, but this is very, very effective. And I don't know if a study has been done to compare the two, but you can spend upwards of $150,000 for an erbium YAG laser to use as an endodontic adjunct, where here you're talking about a couple of thousand dollars, two to $3,000 for the unit. So it's extremely... attractive from the standpoint of its effectiveness and the cost so let's pivot a second to contraindications what are the contraindications associated with using the hfc module Correct. So as you mentioned, that new technology is not very expensive compared to other technologies. It's very easy to use and to adapt. Not to say that lasers and other technologies that are out there are not helpful, but this one is much easily, we can integrate it much easily in a daily practice, whether we are an endodontist or a general practitioner. Now, there are some sorts of contraindications when it comes to using this technology, and especially if... on preoperative radiographs and preferably on preoperative CBCT if we have a CBCT or if we doubt or if we see that let's say the roots of mandibular molars are very close to the mandibular canals or to the mandibular canal, or let's say if you have a premolar that's very close to the mental foramen, we want to avoid using that HFC, that technology, close to it because it can damage the nerves and the blood vessels in that area. So this is one of the contraindications because that electricity and that shockwave, that heat can also, just like you said, cauterize or fry the pulpal tissue, could also do the same thing on the nerve. And so this could generate paresthesia. and much more, if you want, complications that we could avoid just by not doing that technology. So we have to do some case selection, especially in lower molars, in order to avoid the damages that we don't want to do. Is there any contraindications in the maxilla for like number 2 or 15? There's no contraindications in the maxilla by itself, according to the manufacturers, only when we have a proximity to the metal foramen and to the mandibular canal. Some other contraindications, as mentioned by the manufacturer, J. Morita, is if you have a patient that is younger than 12 years old, so I guess in terms of like when we have an open APCs, The concept is that it might maybe damage the tissues beyond the foramen. And if we have, let's say, any cochlear implant or pacemakers, and if you're trying to do vital pulp therapy, of course, we don't want to damage that vital pulp that you're trying to save and to keep. So these are the contraindications in general. But other than that, it's a technology that could be used in any case, whether it's necrotic, whether it's a vital case, whether it's a mandibular or a maxilla, anterior or posterior tooth. And I mean, we shouldn't, if you want, underestimate the extensive anatomy. We all know that anatomy is one of the biggest challenges in root canal treatment. And so adding this technology to dominate or to conquer, if you want, the anatomy gives us... a big plus in endodontics in order to control the microbes, which is the ultimate goal of our treatment. Yeah. I mean, if I was practicing today, I would use this on every case other than what you just discussed. I mean, that's the biggest issue is getting into areas where we just can't instrument. And we, in many cases, we don't even know they're there. Now with CBCT, it helps us. But when I practiced and we had 2D imaging... And traditional 2D imaging, yeah. Traditional 2D imaging. I mean, you've got to be kidding me if you think you're going to be able to see all those lateral canals. These are small little canals that are just very, very tiny that are holding microbes that can cause a failure. Certainly, it could cause lateral resorption later on in life. and killing all these microbes and washing them is important yeah you know you have to bring those microbes uh below a certain threshold and and as you said like the detectors of of where the microbes are and the detector of our disease today in 2025 is is much more sophisticated those detectors whether it's cbct for example is much more sophisticated than traditional periapical x-ray that we have to take on film and develop in the processor. And so now we know that when we have these detectors that can detect where the microbes are hiding and how they are manifesting themselves in terms of like resorptions or lesions or apical disease, we should incorporate technology. that helps us to go and get those microbes where they are since now we know how to detect them. And thus this technology that is easy to integrate and to be used in any case, except in those scenarios that are contraindicated. So just disinfect in a minimally invasive manner because, of course, we can over-instrument the canal. We can open it to a certain size, like you said, used to be done in the 70s and 80s. But at the end, it's... costing us a lot of dentin. So if we can conserve this dentin, conserve dentinal structure and still reach microbial control and exert a certain cleaning. that is superior, this is the best service that we could be offering also to the patient. And in order to save the tooth, get him rid of the disease and tell him that his tooth is going to be in the mouth and without having any risk of having a root fracture or whatever complications due to the thinning of the root canal walls. And this device is really fantastic for dentists that are working in rural areas that don't have the luxury of sending a patient down the road to an endodontist. Often the patient may say, I don't want to go 50 miles or 35 to 50 miles to see my endodontist so just take the tooth out and the choice is either this could help us yeah So, I mean, any tool that's able to help us to control the microbes, especially a tool that is that small, that doesn't need to be like stored somewhere, it's not cumbersome. And it doesn't have more time. It doesn't have more time. It's really in the apex of care. You just have to clip it, use it, and like one step on the pedal gives you the required result. Of course, you have to have certain basic knowledge of root canal treatment. I'm sure like a lot of general dentists today have, even those who are not big fans of endodontics, just like axis cavity, finding the canal, determining the work. latin patency, then employing this tool gives you a big step in controlling microbes inside the root canal system. Yeah. So you're an endodontist, Dr. Safi. Should this instrument, should this tool be used by GPs, endodontists, or both? It should be used by both. It is made to be used by both, especially, I mean, in the endodontic practice where root canal treatments is left. done a lot. In the general practice, if there's a lot of endodontics that has been done, a lot of root canals, it's going to help the general practitioner. I think the hardest step is to be able to understand how it works and to really appreciate the advantages it gives us. It's not only just another gadget that's going to shake or activate this arrogant to a certain degree. It's going to really give us an advantage of like... killing the bacteria in areas we cannot see and even propagating its effect beyond the apex to really help us heal that disease that we are fighting. So we have to really understand this and really value this advantage that we have. And of course, try it. Once we try it and we see how easy it is and we get out of our, in a sense, like comfort bubble or comfort zone that we have with our actual protocol that we have, we can really see that this tool is... It's designed different in order to help us really get where we want, which is to heal and to help us get rid of the microbes and get microbial control. So as we wrap up this episode, Dr. Savian, it's been very, very enlightening. When we talk about a new piece of equipment, we talk about the footprint, but there's really nothing more to add as far as equipment if you already have the RootCX3. It's just a module that snaps on to the actual apex locator. The only thing is the rheostat, the pedal. is that inconsequential adding that rheostat to the operatory It's a very small pedal. I mean, it's so small that it doesn't get entangled. The cable is very small, doesn't get between the feet. And it's very easy to localize. Once you place it in a certain place and your assistant knows where to place it for you, it's just easy to swing between, let's say, your main rheostat, which is for your hand pieces, and then that rheostat, which is for the HFC. So it's very easy. I don't think there's a lot of cumbersiveness in a sense or like, you know, being... lost in in which pedal to use it's it gets to you just like when you drive after a while you know like you know press on gas press on brake it becomes very it becomes a reflex that you have and will not cause any trouble yeah so you teach at pen uh endo program are you bringing this new technology into the so the students get to understand what this is about is this something that's being introduced to endodontic residency programs? So I do teach at Penn. I'm an adjunct professor there. And Jay Morita sent us an example to try. And we've been trying it with some residents, not only for irrigation, but also for gingivectomies, getting out, let's say, papal granulomas and all the other advantages of that. this device can offer to us. And I can say that, you know, there's a little bit of a learning curve, but that's not very complicated. But once we really get used to it and we see the result visually of it, it becomes something that is secondhand that we can incorporate in our dental everyday practice without any problem. It's really nice to see the progression of technology and how it gets introduced into our operatories. And I think every clinician just needs to be open-minded. Listen, when I first started using... the apex locator there was all sorts of problems with it back in the 80s you know you had a little drop of blood in the canal or sodium hypochlorite, and all hell would break loose. We'd go nuts. Yeah, we'd go nuts. Yeah, it's a different one. The objective is the same. Our objective is the same. The approach gets different and gets better with time, whether it's, let's say, apex locators, magnification, illumination with loops. Today, we are lucky that we have microscopes. With radiology, we have CBCT. And now with disinfection or with cleaning, with debriding, with getting a cleaner root canal system. we have this new conduction module that really offers us an advantage to step forward in reaching microbial control. Yeah, I was at the New York show last December, and I believe it was the New York show, and there were tons of dentists at the J. Marita booth trying to get an idea of what this thing was about because they know as practicing dentists that the number one concern for root canal therapy is to kill the bugs, and everything relies on that. If you don't kill the bugs, your root canal... It's going to fail at a certain extent. Yeah, it's going to fail. So Dr. Safi, great discussion. Very, very interesting. And we really do appreciate your time. It was great to talk to another Penn alum. That was a treat. Enjoy the beautiful city you live in, Montreal. And hopefully I'll get to visit there sometime. Really appreciate your time and hope to see you on another program soon. Thank you so much. Cheers. Thank you.