What's New in Endodontic Irrigation?

You're listening to The Dr. Phil Klein Dental Podcast from Viva Learning.com. Welcome to the show. I'm Dr. Phil Klein. Today we'll be discussing endodontic irrigation, its history, important principles, and current techniques and devices. Our guest is Dr. Ali Nasseh, a clinical instructor and lecturer at Harvard School of Dental Medicine in the postdoctoral endodontics program. He is the current director of the Endodontic Microsurgery Course at Harvard and also runs a private practice limited to endodontics in downtown Boston. Dr. Nasseh is also the CEO and president of Real World Endo, an endodontic education, innovation, and medical device company. Dr. Nasseh, it's a pleasure to have you on Dental Talk. Phil, it's great to be with you. We're talking about irrigation today and every endodontic procedure. obviously needs irrigation at least in the conventional traditional way we do endodontics so before we get into that specifically can you give us a historical background on endodontic irrigation Yeah, of course, irrigation has always been a part of endodontics. I think very early on when people did endo procedures, and believe it or not, Phil, they saw the way back to the 1800s where the first endo procedures were being done, and people were trying to experiment, find out what is some of the ways we can save teeth. And what's interesting is at that time, you know, Koch's germ theory wasn't even... clear or Lister's idea with disinfection wasn't even clear but many of the endo general dentists or endodontists well there were no endodontists at the time who were in this domain kind of already had proposed that perhaps the cause of dental disease is microbes which is something that was recently discovered so at that point early on these people like to mills and so on. Very early on, they realized the importance of using maybe disinfectants. At that time, people were using all kinds of caustic agents. Believe it or not, they were using arsenic inside the tooth, even sulfuric acid, potassium. And then later on, well, Lister worked with the development of phenol. Then you had carbolic acid. All kinds of things were added to inside the tooth in order to disinfect. And when it became really clear with some of the studies back in the mid-20th century with Kakashi and Stanley, where people realized that actually the cause really is bacteria and it became proven beyond reasonable doubt when the role of this new concept of endodontics moving away from filling canals to first and foremost disinfecting them came about. And we moved to less and less caustic irrigants that were having less systemic effects and decided to go to... one of the most common irrigant disinfectants that were around, which was basically sodium chloride. to use inside the root canal in order to kill the bacteria and so on. The main reason for that is because sodium chloride was a great disinfectant, but had a couple of other qualities as well that are also very important. And this is how the endodontic irrigation has evolved from very caustic agents. Not that sodium chloride is not caustic, but we now have also learned what are the best techniques and methods to keep it inside the tooth so that you don't end up having any of the potential. caustic effects outside the tooth. Yeah, that's what I was going to ask you. So again, I practiced endodontics quite a while ago, but sodium hypochlorite was the obvious go-to irrigation material to use. It was diluted, obviously. I believe it was like 1 to 10. sodium chloride comes in a bunch of different concentrations when you buy it full concentration and even full concentration has gone up in in there's been like inflation uh fill on the super hot chloride solutions as well five and a quarter percent used to be full strength but now when you go to to CVS or any of these places to buy full strength hypochloride, it could be all the way up to 8%. So it's quite a bit. It's important for doctors to look at the actual bottle that they're getting this stuff from to make sure what the concentration is. But it has been found to be disinfecting at concentrations of even half a percent, which was the original Dawkins solution back in the early 1900s. That's a serious one to 10 dilution, as you said. And as you go up in concentration, what you gain is more dissolution of organic tissue, which is also part of an important part of all irrigants. Yeah, denaturing the proteins. And that obviously helps the material break down so it could be washed out. So what are the most important principles of endodontic irrigation that every clinician should know? So I think, as we just mentioned here, the key concept to understand is that all irrigation inside the tooth is essentially trying to achieve three main things. One is to disinfect, obviously, but then also what we're trying to do is also to decalcify, which is to help remove the smear layer. And then lastly, also to dissolve the organic tissue, because remember the pulp. tissue is fairly tenacious and is connected into all these fins and anastomosis inside the root canal which isn't round like what a graphic artist would show you so you have all of this tissue beyond the reach of your root canal file so you can't mechanically clean it so you need to use a component of irrigation in order to remove the tissue the biofilm and also to decalcify the dentin which is to also remove the the smear layer. So chemo mechanical instrumentation is the key thing that we have to keep in mind because the mechanical component part of it is instrumentation, but there is a chemical part that is as important, if not more important, that is... reaching those areas of the canal where the blade of a file cannot reach to cut off and remove the biofilm and the bacteria and the tissue. So that's why it goes hand in hand and it really achieves those three functions of disinfection and decalcification, which is removal of the calcium of the dentin and so on. So the smear layers removed and then all tubules are not clogged, dissolution of tissue. I think we've had a big... kind of using the term irrigation as a panacea has been a problem for us in the profession. We've been defining the word irrigation to equal to whatever solution we're using inside the tooth. But I really believe that more detailed version of the term should be broken down, irrigation should be broken down to macro debris removal. and disinfection that's essentially is what irrigation is the macro debris removal means that as our files rotate or reciprocate or whatever motion they use inside the tooth they cut debris and that debris is oftentimes loose in the canal and that debris has to be removed otherwise it gets clogged and not all of the debris is removed with the file through the file flutes What ends up happening, a lot of this stuff is loose in the canal and it can precipitate. It could get packed with the file. And that's the main reason we end up getting not only the smear layer on the canal, but also as it gets packed apically, it could potentially block us. And if you get close to the apex, that debris will get past the apex and cause biological inflammation because that tissue is inflammatory, full of biofilm. It'll cause post-op pain for patients. So managing that macro debris removal is a very different story than just... this infection. And I believe that the best material that we have for removing the macro debris removal, besides our regular positive pressure irrigation and negative pressure irrigation, is the addition of some type of an activating factor such as ultrasonics, which will then help remove dislodge. and evacuate the canal from this debris. Once everything is all the macro debris has been removed, now at this point the role of disinfection is very important because you want to make sure you disinfect the space that you're going to leave the pavement. I don't see any reason to just start using sodium hypochlorite right from the get-go for the whole time, because that main job of that is the disinfection of sodium hypochlorite, as well as obviously removal of the organic tissue. But the use of ultrasonics at the beginning part of the procedure would be even more helpful in terms of removing some of this macro debris, get it out of the way, then you can clean the canal and shape it. and then get in there and disinfect it at the end before you're obturated. Don't you need to enlarge the canals, though, before you could get effective macro debris removal? In other words, you have to... That's a catch -22, right? That's like a paradox, because in order to enlarge the canal, you're going to create macro debris, and then you can't enlarge the canal to remove the macro. So you have to remove the macro debris as you are enlarging the canal. And that's part of the reason why... constant use of interrupted ultrasonic irrigation by going back and forth and doing it. Every time you use a couple of files, you can go back with your ultrasonic with fluid. And that fluid could just be water, to be honest, at this stage of the game, as you're going down the canal in a crown down fashion. That's the fastest, most efficient way of removing the debris. So you just have to make sure that you put the ultrasonic power on a lower side so that it's merely just agitating and with the water flushing out the debris rather than trying to instrument. So what kind of ultrasonic devices are we talking about here? The conventional ultrasonic devices are adequate for this purpose. And there have been a few studies. I mean, there were some original studies back in the 80s that showed the power of ultrasonic in terms of removing the smear layer and removing debris from inside the canal. So we're not talking about the... you know, the Cavitron and things like that. We're talking about the piezoelectric units, not the magneto -restrictive units like Cavitron. A piezoelectric unit, I use the Forza V3, but there are a number of them out on the market that you can use. And the most important part of the use of ultrasonics is to use it with a wet tip, which is a tip that... applies, has a water port and allows water to come out into the area and allow the debris to be flushed out. The mistake that I see most people use film when they're using the ultrasonic is they use dry tips, in which case they're really not flushing out the debris. Ultrasonic is only really conducted through the water medium that acoustic streaming and agitation and cavitation uses water as the medium. So you can really, there's really no place for the use of dry tips and endodontics, and that's a huge problem. I've seen happen over the past couple of decades. Using that ultrasonic device, you put tips on and then water is driven into the canal with the tips getting almost like a camp piece where a burr is cooled with the water flow. Yeah, exactly. Some ultrasonic units have a self-contained water port, and some of them actually may be able to use even other types of irrigants rather than either sterile saline or water. You could use some more disinfectants in there. But to be honest, I don't think that's necessary at this stage of the game. Most of the other, almost all ultrasonics have some type of a water port that gets connected as a quick connect to your... own, you know, water source that you're using on your hand pieces, whether you have a self-contained unit or you have regular, you know, plumbed units, they should also have a quick connect where you can connect these and then you would be able to source your water from the same source that you get in your hand pieces. What happens if you use a syringe to just gently place the fluid down into the chamber and it's carried down into the canal and then you use an ultrasonic device that does not have water flow? You still have a wet tip. Yes, you sure do. That's a great point. And that is essentially your passive ultrasonic irrigation that is oftentimes recommended as your last type of regimen in your protocol in which you place a solution and then you activate it with your ultrasonic tip that allows, whether it's, you know, hypochlorite, whether it's EDTA, to kind of decalcify and remove the smear layer or disinfect further. passive ultrasonic irrigation. I'm talking more about continuous ultrasonic irrigation. Now, you can have, as you said, you can put a syringe on the side where you're irrigating and suctioning at the same time with a solution. But it's also important to know if you're using a caustic irrigant, such as hypochlorite, too much ultrasonication, too close to the apex, you could potentially push a little bit more of the debris out. What is the device that you like to use in your practice? Irrigation comes either in a positive pressure, which is basically the use of a needle and syringes, or negative pressure, which means that you actually, instead of irrigating deep in the canal with a needle tip and then putting the suction up at the axis... to suction up the excess you put a micro suction out of the apex of the tooth and then you add the hypochlorite up on top and what that does is it allows the higher volume of hypochlorite to safely go down to the apex and then come back up to suction so there was a few uh the negative pressure system that first came out was the endovac and that's a very good system there's been different versions of it who makes the endovac is made by Sybron endovac is made by Sybron So that's for negative pressure. For positive pressure, making sure that you have a thin needle that is side-bented and close-ended. So for safety reason, it can go all the way down. There are a number of units on that front. The Ventsply has a 30-gauge needle that does that. Brassler has a 31-gauge needle that has also a stopper on it, and that goes all the way down to whatever working length, because you have a stopper and you can determine how deep you want it to go. So you can get fairly deep. positive pressure irrigation safely. If you do go that deep, it's important to make sure that you have a more diluted hypochlorite solution that is... not going to cause any issues and to that effect we've actually been working on a new hypochlorite formulation that would be available soon too and this one's called Triton and what it is is essentially a combination of a diluted version of silver hypochlorite along with a chelating agent and a saponification agent so you get both lubrication chelation and disinfection and dissolution of organic tissue all in one irrigant. Because Phil, you know, historically, as I mentioned, you have different types of chemicals used for these three main functions of an irrigant, which is to disinfect, dissolve tissue, and decalcify. But it's been kind of, you know, you always have to have a hypochlorite and EDTA, and you always have, in a proper protocol, you always have to alternate between the two because you want to decalcify before you irrigate, because otherwise, as soon as those dentin chips are left inside the root canal walls and clogging the dental tubules, as soon as hypochlorite hits those chips, it gets deactivated. That's another big problem in irrigation is the question of the activation and buffering of sodium hypochlorite the moment it comes in contact with dentin. Within three minutes, essentially, that layer that's in contact with dentin is just salt water. It is not hypochlorite. It's not doing any disinfection at all. That's three minutes for that to occur? absolutely within three minutes you have uh as soon as hypochlorite hits dentin that layer is uh turned into salt water that's why some of these uh older kind of uh recipes of people saying oh you need to sit and soak your solution inside the root canal it just it doesn't work because you know the solution at the point of contact with the dentin which is the only part that counts is essentially salt water at that point it's not really if you're doing anything yeah if you're causing some turbulence though within that sodium hypochlorite you don't have that layer sitting against the dent very long but what i wanted to ask you is how does the EDTA perform mixed together with sodium hypochlorite in this triton? What is the name of the product? So yeah, triton is the solution that has these chemicals all combined. Now, you cannot chemically mix EDTA with hypochlorite because you do get... within also three to five minutes, they consume each other. So that's always been a problem. Otherwise, we've always wanted to, why alternate? The ideal situation has always been to kind of combine the two together. It would have worked beautifully, except that they kind of interact with each other and they kind of nullify each other. So this has been in the works for a number of years where the chemists that... essentially developed this product, Triton, worked on a number of substitutes to EDTA that is not consumed by sodium hypochlorite. So you have a number of chelating agents and decastifying agents in there that, unlike EDTA, are not consumed by sodium hypochlorite. Now, sodium hypochlorite is very caustic, so it eventually will break these down, but what it does is it allows you to have some time. Triton is a solution that comes in a little bottle that has two different containers, just like your catalyst and base when you're mixing any of your composites that contain a catalyst and base. This is an irrigation solution that has two different jars next to two cylinders with two different solutions. One is the chelation and the saponification agents, and the other one is the hypochlorite. And it has one nozzle, you draw from one, and it... mixes the exact proper amount of each one into your syringe, and all of a sudden now you have one syringe that contains your hypochlorite at a little bit of a lower concentration than full strength, so it's a little bit less toxic, but because of the fact that it's combined with surfactants and with saponification agents. and with a number of chelating agents all in there. So you have everything all in one. So it takes two and a half hours to the whole thing to kind of neutralize. So it does give you plenty of time to do your endodontic therapy. When is this product going to be available? So it should be available within about a month or so, probably before the end of the year. Is that through Brassler or another company? That is through Brassler, yes, as well. That sounds like a time saver. In the old days, when I practiced endodontics, it was sodium hypochlorite intermittently used with EDTA, which was RC prep from Premier and rinse and chelate and rinse and chelate and instrument. And, you know, you just keep doing it. You know, you're just doing it instinctively. It's not based on any particular perfect recipe of rhythm, but it's just something you do in your office on a regular basis. And the end result is you want to make sure you don't push the sodium hypochlorite out the apex and you want to make sure you. get the canal super clean. You're deeper into the science than I am, Ali, so we're going to certainly take your word for it here. It is certainly a clinical workaround so that it gives you optimizing, it creates more efficiency in terms of not having to use two different syringes and two different needles or two or three different syringes and needles on that front. But more importantly, the combination of the two together would work synergistically because if you can chelate while you're disinfecting. it does actually create a much more deeper penetration of sodium hypochlorite. And based on the initial studies that have been done in-house, the scientists have found that you do, dentinal chips are one of the biggest detractors to sodium hypochlorite doing the work. So if you could decalcify them in the presence of dentinal chips, you are going to have a deeper disinfection. And in fact, Independently, at the University of Pennsylvania, they've done some studies on this material and they find exactly the same thing, which is that in the presence of dentinal chips, which has always been a detractor to disinfection because of sodium chloride deactivation, Triton. performed much better than full strength hypochlorite. That makes a lot of sense. That's a very, very good point. I'm glad you pointed that out. There's no point in putting sodium hypochlorite down the canal if it's going to be neutralized within a short time. You think you're doing something, but you're effectively not. And I assume this helps on these lateral canals. The disinfection process is better. The chance for a failure due to a flare-up from tissue left in an accessory canal probably would be reduced, I would assume. no absolutely because don't forget now instead of alternating occasionally between these two products you are essentially using edt EDTA equivalent, not EDTA, obviously, as I mentioned. But a decalcifying agent or a chelating agent and a disinfectant throughout the whole procedure. And as a result, you are exposing the decalcification a little bit more. So you're actually going to end up with much cleaner removal of the smear layer. Because, I mean, most of us, Phil, I'm sure you remember, at the end, we're supposed to kind of do some decalcification and remove the smear layer. But nobody really leaves that in there for five minutes. Everybody just rinses quickly with it. This will allow you to have it all throughout the procedure. Yeah, for sure. So we really appreciate your time on this podcast. I thought it was very interesting. We'll be excited about getting some results from some of the research that's done once this product becomes commercialized, which should be, you said, in a couple of months from Brassler. Brassler is a fantastic company. They're the sponsor of this podcast. And I know Dr. Nasseh does a tremendous amount of work with them, product development and so forth. And he has a great educational program, as we said. in the introduction real world endo so visit real world endo and you'll find tremendous amount of information videos podcasts that dr nasia works on which is really great stuff thanks very much and we'll look forward to you on the next podcast thank you