Mastering Pulp Therapy and Perforations with Modern MTA

Initially, what's going to happen is there's going to be a big spike in the pH. And what that's going to do is that's going to initially cause a superficial layer of necrosis in the pulp tissue. But believe it or not, that's kind of a desirable thing for a couple reasons. One is that's going to eliminate any bacteria. But that necrosis is then going to allow and stimulate reparative cells to come to the site, such as stem cells, which ultimately start forming odontoblast-like cells. and further down the line start placing reparative dentin. And as a matter of fact, it attaches onto the MTA-like material because that initial cellular necrosis is being replaced with hard mineralized tissue. Welcome to Austin, Texas, and welcome to the Phil Klein Dental Podcast. So let me set the stage with a scenario every general dentist knows all too well. You're removing decay, working carefully, and you feel you're getting close to the pulp. You finish your prep, and now you're either right on top of it, or you see a small mechanical exposure. The patient's dental history reveals some brief sensitivity to hot and cold that resolves pretty quickly. Radiographs look clean, no periapical radiolucency. So now comes the real question, what's the next step? Do you move toward more aggressive treatment, or is this a case where you can preserve the vitality of the pulp? That's exactly what we're diving into today. In this episode, we're going to talk about how MTA, mineral trioxide aggregate, can be used as both an indirect and direct pulp cap in situations just like this. More importantly, how it doesn't just protect the pulp physically, but actually helps stimulate reparative dentin formation right over the exposure, giving the tooth a chance to heal and remain vital. We'll talk through the clinical workflow and technique nuances and how to consistently get the best results when using MTA in everyday practice. We'll also take a look at newer formulations, including MTA-VPT, which address some of the historical challenges with this material, like faster setting times, improved handling, and no discoloration, making it far more practical chairside. To guide us through all of this, I'm joined by Dr. Ryan Walsh. a board-certified endodontist, researcher, and author practicing in Keller, Texas. Before we bring in our guest, I do want to say that if you're enjoying these episodes and want to support the show, please follow us on Apple Podcasts or Spotify. You'll be the first to know about our new releases, and our entire production team will really appreciate it. Dr. Walsh, welcome to the show. Dr. Klein, thanks so much for having me. Yeah, it's really nice to have an endodontist as my guest. Before we get into our discussion, though, Dr. Walsh, I do want to take a minute and talk about what MTA actually is, because it's one of those materials that gets mentioned quite a bit, but not always fully understood. So as an overview, MTA, or mineral trioxide aggregate, is a calcium silicate-based cement that was introduced into dentistry back in the early 1990s. And what made it so different right from the start is that it doesn't just sit there as a barrier over vital pulp tissue. It actually interacts with the biology of the tooth. So it's essentially bioactive, which we'll talk about today. So when you place MTA, it reacts with moisture and releases calcium ions, which helps stimulate the formation of reparative dentin. And at the same time, it creates a high pH environment that's naturally antibacterial, and that's important. because it not only physically protects the pulp, but as I mentioned, it's antimicrobial and it supports healing. So what I really like about MTA as an endodontist is how versatile it is in clinical practice. Whether you're doing an indirect pulp cap or managing a small exposure with a direct pulp cap, MTA gives you a fairly predictable way to help the pulp recover and stay vital. Because it seals so well in a moist environment and is biocompatible, it's ideal for perforation repairs and apicos. But I think before I turn the mic over to you, I think it's important to mention to the GPs out there that MTA... an endodontist material. It's very much a general dentist material as well, especially now as more of us focus on minimally invasive dentistry and are doing everything we can, obviously, to preserve the natural tooth. So I think we can agree that MTA has become a proven and reliable solution, I guess we can say, for really deep cavities and vital exposures. And finally, newer formulations have made a big difference. We'll be talking about them today. better handling, faster set times, improved aesthetics. So it's a lot more practical to use chairside than it used to be. So what we're going to discuss today is if you're trying to preserve pulp vitality and avoid more invasive treatment when possible, MTA is certainly one of the most valuable materials we have for that purpose. So to get this episode started, by the way, as a newer, much younger endodontist than I am, was I on target there? I think so. Yeah, absolutely. Spot on. Okay, good. So let's start with the big picture. What is the real clinical problem that MTA has solved that materials like calcium hydroxide just could not solve? That's funny you ask that question that way about... relationship between MTA and calcium hydroxide, because they're kind of inextricably related. You know, as you had mentioned in your intro, that MTA releases hydroxide and calcium ions. So MTA, for lack of a better description, is a medical grade Portland cement with different additives, different contributions and things like that. But really, it's a hydration reaction. It's soaking up the moisture from pulp and from peripheral tissues and using that to set. And as it sets, it's releasing calcium hydroxide. Whereas in years past, you just place calcium hydroxide over the pulp and you just really hope for a strong enough irritation reaction, more or less, to stimulate this dentin bridging. Where MTA has this prolonged release of calcium ions and calcium hydroxide, it provides a much more predictable way to do pulp treatment, whether it's vital pulp therapy, like you had mentioned before, perf repairs, things like that, to stimulate that hard tissue formation in a much more predictable manner. And it forms a really tight seal between the restorative... restorative material, the MTA and the dentin or the tooth structure. Whereas calcium hydroxide, we know we're putting it in there as a paste. It's going to resorb over time. And that's the big advantage of MTA over the classic Dical. That's still around today. And you still see these restorations with these little dark void syndrome years later, because it's washed out over time. Yeah. And I was going to ask you, do you think dentists have... the difference between using a calcium hydroxide product like Dical and the deficiencies clinically that that brings to the table versus MTA, which you just described so well as something that not only releases the calcium, but actually stays there and seals for long periods of time? I think this is something that we as endodontists collectively maybe haven't advocated as much or haven't been as vocal about. Even going back to the early generations of MTA in the 90s, which were probably very prevalent. when you were going through school or coming out of residency or early on that, yeah, you know, we just maybe weren't as vocal or cognizant kind of pushing that forward to general practitioners and pediatric dentists saying, hey, we have something that's new and improved that's bigger, better, faster, and stronger that's really here to stay. Yeah, I think it was the workflow, the slow setting of the early MTAs really hurt the, you know, the acceptance, the clinical acceptance of the material. MTA is often described, as I mentioned, bioactive. Can you walk us through what's actually happening at the cellular level when it's placed near vital pulp? Yeah, absolutely. So as it's placed initially, you're going to... it in contact with the pulp tissue. And so initially what's going to happen is there's going to be a big spike in the pH. In other words, you're going to go from a body neutral pH up to about 12, 12 and a half, give or take. And what that's going to do is that's going to initially cause a superficial layer of necrosis about a millimeter or less thick in the pulp tissue. But believe it or not, that's kind of a desirable thing for a couple of reasons. One is that's going to eliminate any bacteria that are still floating around in the superficial pulp tissues. But that necrosis is then going to allow and stimulate other reparative cells to come to the site, such as stem cells, which ultimately start forming odontoblast-like cells. And further down the line, start placing reparative dentin. So you get this dentin-like repair, this dentin bridge directly adjacent. And as a matter of fact, it attaches onto the MTA-like material because that initial cellular necrosis is being replaced with hard mineralized tissue. Go away from vital pulp to a dentin bridge and then subsequent vital pulp underneath. So if you have a vital pulp exposure, what would you recommend to the general dentist about the timeframe? Like when should they expect to see something happening radiographically, for instance? A few months is very realistic. You know, we've seen cases back at, you know, six weeks, two months. And we started seeing some initial Denton bridging being laid down. And obviously, if you're getting out to three or six months, you can see some very definitive calcific tissue on the pulpal side of that. MTA-like material. So what would you say, Dr. Walsh, to a general dentist who had a vital pulp exposure, small one, got the bleeding under control, used MTA, but they didn't want to put the restoration right on top of it at that same visit? They wanted to make sure the patient was, number one, asymptomatic, and number two, they wanted to wait and see that some dent and bridge formation was occurring, and then they would go ahead with the final restoration. What's your thought on that? Yeah, I say I don't see any need to have to wait that long, especially with some of the quicker setting materials we have these days, like MTA VPT from Voco. I mean, it sets so quick that you can place that material and confidently restore right over top. And then continue to evaluate the tooth. So I always think recalls are important no matter what you're doing with pulp tissue. As far as if it's a mechanical exposure, if you're doing a pulpotomy spec or full. But I think follow-ups, you know, one month, two month, three month are really important. But I don't see any need to delay that permanent restoration. We know that the faster that we can get that repair done and then subsequently rebuild that tooth structure, the less likely they are for cracks, fractures, you know. Take this out of the patient's hands, right? Don't rely on them to be diligent about following up and maintaining recall intervals. You know, definitively restore that tooth as fast as possible after the repair. I think it'll provide a predictable long-term success. Yeah. So you said that it has a three-minute setting time. So that's very convenient as far as putting the restorative material right on top. So you drop the MTA. that's the vocal product you mentioned. And then in three minutes, you could put a restorative material on there, a direct restorative right away. And that's something that would make sense. And I agree with you. What about a crown though, where there's more of an investment, there's more chair time involved, and then we have that pulp exposure to worry about. Would you avoid the crown and just go with a direct restorative if you could? And then in a certain amount of time, knowing that you essentially need the crown. down the road, do it after you start to see some form of dent and repair radiographically, or it won't even bother you to go straight to the full coverage. I think a lot of that also has to do with the patient's risk tolerance and threshold, as well as the dentist's. But if it's a small mechanical exposure, I think the chances of this being a very predictable long-term success is very high. If you want to place a direct restoration, wait a couple months and then go ahead and prep it for a crown, you know, I don't see any adverse impact for doing that. If you want to be sure that you're seeing that pulp repair, but sometimes you really never see a really thick calcific bridge, even though histologically it's there, but sometimes you don't see a definitive bridge, even though I would say it's like anything else. It depends on the angulation of the, of the X-ray beam. In cases with direct pulp exposure, when do you say as a clinician, I don't think MTA is going to fix this? Is it the size of the exposure? Is it the fact that you can't stop the bleeding? Is it the patient's medical history? Maybe they have a history and also their risk factors being very... I know you're an endodontist, you're not working in a GP office, but talking to a GP, if they ask you, where do I draw the line here? You know, I have an exposure. I'm from the mindset that, you know, hope is not a strategy and I just don't want to risk it. So I'm thinking about sending it out to you for full molar root canal. What's your response? Yeah, I think history of symptoms is important, right? Getting an accurate diagnosis is a number one paramount. I think I'm preaching to the choir as an endodontist to endodontist, but getting a good diagnosis, first of all, making sure you have complete caries removal and then evaluate the bleeding or the actual status of the pulp. I mean, like you said, if it's bleeding uncontrollably or it won't maintain hemostasis after a couple of minutes, I think the chance of that pulp treatments. decreasing very quickly. But on the flip side is that if you give it a couple minutes, apply some sodium hypochlorite on the surface, and it maintains hemostasis after five minutes, give or take, then I would say the exact opposite. Great. Let's place an MTA pulp cap or a pulpotomy over that and just continue to monitor. Is that what they're currently teaching now to slow down the bleeding of a pulp exposure to use a cotton pellet of sodium hypochlorite? Yeah, I just use, per the AAE guidelines, I just use sodium hypochlorite. I don't even put it on a cotton pellet to place pressure. Just gently apply it over the surface, just if you were to like wash it or flush it with saline. You know, if you're to flush an open wound anywhere else on the body, that's how I use the- And that's diluted. I think in my endo program, they were recommending three to 6% concentration of sodium hypochlorite in the irrigant. It depends. I mean, if you go buy Clorox from Costco, it can be anywhere between 6%, 8%, 10%. I've seen it vary over the years. A lot of the industry standard things, proprietary irrigants are right about 6% or 3%. I tend to go with 6%. But I think they sell sodium hypochlorite already in irrigation syringes. They come already preset. Preloaded, ready to roll. Yeah. So MTA, we know, plays a big role in pulp therapy. What about perforation repair and apicoectomies? It's not something the typical GP is going to do. Sure. But what makes it so effective in those surgical scenarios? Yeah, the exact same properties that make it real favorable and make it favorable to other. biologically hard tissues, right? So you're increasing that pH, getting rid of any potential bacteria source. You're stimulating hydroxyapatite formation. Again, that constant release of calcium reacting with the phosphate in the body. Calcium and phosphate, you're producing the precursors for hydroxyapatite. And from there, now then you're recruiting those cells to form a dentin bridge or osseous tissue. It's really just the same type of reaction just applied at different levels inside the tooth. Yeah. So if a dentist, a general dentist, not that endodontists never perforate, but let's say, let's put it on the GP. Let's put it on the GP. So they're taking on a case that maybe they should have referred out and they got a little bit ambitious, endodontically ambitious, and they perforated. number 30 on the side going down one of the roots small perforation and they bypassed it and they got down to the canal apical foramen area and they were able to do all their endodontic treatment but they still saw they still see some blood as they're drying the canal there's a little bit of seepage of blood in the coronal part of one of the mesial roots what do you do clinically for that I mean, I guess some GPs would send that out to an endodontist at that point, but the one that wants, let's say they're in a rural area, there's not an endodontist within 35 miles, patient wants to get it done. What would you recommend to the GP on the clinical protocol for sealing that perforation in that case? Yeah. And in a case like that, I'd absolutely recommend using an MTA -like product because that's what they're meant for. I would caution them to make sure that you can see the perforation because you don't want to inadvertently... uh let some of this material fall down to the apex because again it's medical grade portland cement so if it falls down there it's it's going to harden up over time and again some of these quicker setting materials with three minute set times you don't have a lot of wiggle room but if you can see the perforation if you can clearly define that perforation repairing it with an MTA-like material is an ideal situation. The faster you can get that repair, the more predictable. Right. So you mix that up and it's a pretty stiff mixture, right? It's not like soup. You want it to be a little pasty. Yeah, exactly. I say wet sand, something that's kind of packable. Everybody kind of has their own little niche. The MTA VPT comes with a nice dropper that kind of tells you how many drops to scoops and that creates a really consistent mixture. And I found that to be pretty advantageous. Right. So then you use kind of like a plugger and a hand instrument and just kind of pack it in there. And then make sure, that was a really good point you made, Dr. Walsh, is not to let any of that MTA get down the canal. Because first of all, if it sets up in the canal, that's not fun, right? Because you've just blocked yourself off. So for our GPs out there that are doing this, what's your recommendation so that that doesn't happen and the canal stays patent? I don't know about you I'll just use a little a paper point you know I have them sitting right there anyway put that paper point to length and I usually try to deliver the the MTA either from an endo block or a map system. And then with a plugger, kind of condense it against the side. That way, when I'm done, you just pull that paper point right back out. You still have your pathway. And you're not, like you said, you're not blocking yourself out or setting. Obviously, you don't want to push anything through the apex, like you mentioned. But you certainly want to irrigate the canal and maybe use a smaller instrument that's way smaller than the final diameter of that canal, what you've instrumented it to, so that you can make sure you have a glide path all the way to the apex. Nothing's blocking you out. It's one of those things you just don't want that kind of surprise. Yeah. Surprises and endodontics are a bad thing. Yes. Yes, they are. So that's really good to have around then for any GP. And there's not an endodontist around. You want to be able to seal that. Would you recommend if you do get a perforation and you're doing an endodontic case to seal it and then not obturate the canal that day? Just place some calcium hydroxide in the canal, put a cotton pellet in there and temporize it. make sure the patient is comfortable or because a lot of times you can have a perforation and it's asymptomatic for a year, two years, and then it goes. What do you recommend? Do you think it's good to wait or just go straight up and finish your root canal? Well, I mean, I think you could easily argue both sides of this equation. My partners and I do a lot of two-step endo, you know, so I don't see any harm in putting calcium hydroxide. You know, the chances are if you just created a perf, you might be a little flustered anyway. You've already used a good chunk of your time now trying to repair it. It's like sometimes just putting calcium hydroxide in the canals, taking a breath and getting another run at the tooth, you'll be a little bit more calm and hopefully more successful. But that would be my advice to GPs is that... don't rush through that. That's okay. If it happened, it happened. Let's address it, repair it, and move on. But there's no need to have to rush to finish that date. Give yourself the benefit of the doubt and see them back in a couple of weeks. Yeah, no, good advice. So earlier versions of MTA had some well-known drawbacks. Handling, setting time, like I mentioned earlier, is kind of long. which probably precluded some dentists from even using it. Staining, discoloration was one of the drawbacks. From your perspective, Dr. Walsh, how much have modern MTA materials improved the day-to-day clinical experience of using it? Yeah, I mean, huge, huge. And nothing against the original versions of MTA or the kind of host of them that came out within that first decade. Not only are the main drawbacks addressed, such as staining. I mean, a lot of times we're using these materials in young adults or young patients with anterior teeth. So you don't want that tooth to... or gray over time. We're now using radio pacifiers such as tantalite or zirconia that don't stain. Look out for materials that contain bismuth or bismuth oxide because they're going to discolor the tooth over time. So if you can stay with one that's non-staining with tantalum or zirconia, you're going to be ahead of the game. Like we've mentioned a few times, shorter setting time, shorter setting reactions, but also handling. The smaller particle size makes for a really easy packable, smooth material. You know, it's not like you're packing pebbles into the canals. It's a very refined process these days. And I think just from a technical standpoint, that the newer mixes, the newer materials handle so much better than the materials of yesteryear. Yeah. And that's a good point you made about the actual texture of the powder. Because I know back in the day, there was one cement, I don't know if they still make it, it was called Roth cement, R -O-T-H. It's still around. It's still around, yeah. And I know they don't use eugenol cements endodontically as much anymore. What kind of sealer do you use in your practice? Yeah, I'm using an MTA-based sealer. Okay, so you have an MTA, yeah. So back in the day, raw cement was very popular. The reason why I used it was because the actual powder was so finely ground that when you add the eugenol, it was just so creamy and there was no impedance to dropping the accessory cones in. one after the other. At that time, we were using lateral condensation. So you're saying this new... So MTA-VPT, which is VOCO's product, that has that handling characteristic that you're talking about? I think you described it real well. I mean, it's a self-mixing product, right? So you have to mix the powder and the liquid. But yeah, the particle size is really fine. It allows for a smooth mixture. So again, when you're kind of packing it down into some of these canals or trying to pack it onto a small pulp exposure, it handles really well, especially for a product that you're mixing and trying to create the same mix time after time. That fine particle size makes it pretty easy. Yeah, and it's interesting because some dentists do not want to have a self-cure material. They don't want to wait. Although the MTA-VPT... is only three minutes, but three minutes is three minutes, and it's eternity when you're really busy. But there's no curing light necessary, which means there's no additional heat. There's also no resin in the formula. So it's really up to the dentist's preference, what he or she prefers to use as far as an indirect pulp cap or a direct pulp cap. But if you're using MTA and you're suffering with the set times, and some of these MTAs have discoloration side effects, then MTA VPT from VOCO should certainly be something you should be looking at. To wrap it up as we get close to the end of this episode, and it's been very, very interesting, Dr. Walsh, again, I really appreciate you coming on. With newer MTA formulations improving workflow and ease of use, do you see MTA becoming the standard of care for... vital pulp therapy moving forward? Yeah. I mean, we have study after study that supports that exact statement, that it should be the standard of care for any type of pulp treatment. And it has been for a while. And I think we as endodontists and people who are using these materials need to advocate stronger for their use because they're so good for the pulp. They're really good dental products. They're hydrophilic. Not many things that we have in dentistry are hydrophilic. They're self-setting and they promote hard tissue formation. So what more do you want in a tissue to be put on the pulp? So for our listeners, if you're interested in learning more about MTA or MTA-VPT from VOCO, just check it out online and do your research, compare, ask your colleagues, ask other endodontists what they think, and then you'll be comfortable and confident about the material you're using for your indirect and direct pulp caps. Dr. Walsh, great talking with you. Pleasure. And a fellow Texan. I'm glad to hear you're from Texas. You're in Keller, Texas? I'm in Keller, just north of Fort Worth. Right. And I'm in Austin. Yeah. All right. Love it. All right. Very good. Thanks again for having me on. Yeah. Thank you so much, Dr. Walsh. You take care.