The Latest Scoop on the Direct Pulp Cap

You're listening to the Phil Klein Dental Podcast. In today's podcast, we're going to be discussing the direct pulp capping procedure specifically related to the mechanical exposure during caries excavation. So to begin, let's ask the question, what is our objective in doing a direct pulp cap? From the physiologic perspective, we want to maintain the vitality of the tooth by facilitating the repair of the pulpal tissue that is in direct contact with the exposure. Our hope is that by placing a bioactive material over the exposure site, we're going to get pulpal tissue healing, as well as the formation of a dentin bridge that will insulate and protect the pulp for many years to come. Now, from the perspective of practicing conservative dentistry, where we want to minimize more complex procedures, save tooth structure, and spare the patient the fear and cost of doing things like root canal and crowns, the direct pulp cap procedure is a fantastic option. Now, having said that, this procedure is not for every patient. It's our job as clinicians to make the decision whether the patient is a good candidate for direct pulp cap or not. If you decide to do it and the conditions are right, the procedure can be a great service to the patient. Research shows that when doing it correctly with the right materials, the success rate is high. And as I mentioned, this kind of treatment fits perfectly into a practice that focuses on conservative dentistry. Now, on the other hand, even if your practice is all about conservative dentistry, if the conditions are not right and it's doomed to fail, then you're not doing the patient a favor by doing a direct pulp cap procedure. All you're doing is delaying the inevitable and dragging the patient through the process longer, during which time the patient might be experiencing a lot of discomfort and to say the least, disappointment. So let's talk about when to do it and when not to. 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First and foremost, if we see deep decay on the x-ray and realize that a pulp exposure is a possibility, we need to ascertain as accurately as possible the state of the pulp before we start treatment. In other words, we need to make an endodontic diagnosis prior to getting the patient numb and, of course, prior to commencing caries excavation. For instance, teeth that present with symptomatic irreversible pulpitis or pulpal necrosis are not candidates for pulp capping procedures. And this could be found through vitality testing. And that's a subject for another podcast about how we determine an endodontic diagnosis of irreversible pulpitis versus reversible and pulp necrosis. So we'll talk about that on another podcast. But we need to determine what the endodontic diagnosis is before we start. In addition, teeth that present with percussion or palpation sensitivity and or a radiolucency at the root apex should also be excluded from pulp capping. And again, the reason for this is that we do not want to do a direct pulp cap on a tooth that is severely inflamed, what we deem as irreversible inflammation, nor do we want to do a direct pulp cap on a necrotic tooth. Now, on the other hand, if after doing some cold stimuli testing, we find the patient eliciting a normal pulpal response or even a response indicative of symptomatic reversible pulpitis, then we can say we have a pretty decent chance of a successful direct pulp cap. In these cases, if you follow the correct clinical protocol, as we'll be discussing in this episode, which includes using the right materials and achieving hemostasis at the exposure site, you can expect complete healing of the pulp and an effective dentin bridge over the exposure. Okay, so you've completed your diagnostic tests and you believe the tooth is vital and has plenty of healthy tooth structure. So you get the patient numb and begin cleaning out the tooth. Now, for this example, let's assume you're working on a 30-year-old adult with deep decay on tooth number 19. Now, one thing to keep in mind when a carious lesion is in close proximity to the pulp chamber, it is advised to utilize rubber dam isolation. This helps to minimize any contaminants into the prep, as well as to simplify the transition to endotherapy if a pulp exposure occurs that necessitates endodontic therapy. All right, so you think you have it pretty cleaned out, but after running a hand instrument over the floor of the prep, you still detect a little bit of what you think is infected dentin. Now, it should be noted that in order to improve our chances of clinical success in this procedure, we need to concentrate on completely removing demineralized infected dentin. Some of us may have the mindset that it's better to leave a small amount of infected dentin at the scene in order to avoid a pulp exposure. That's not the case. Doing that will actually do the reverse and almost guarantee a failure. So all the infected dentin needs to go. So as you continue to remove the last bit of infected dentin, you clip the pulp horn and you have an exposure. Now, even though you realize you have an exposure, you still need to continue to eliminate all the infected dentin because of what we just talked about. Because if infected dentin tissue remains, we will likely get chronic inflammatory cell infiltrates, pulpal inflammation, which will likely compromise the vitality of the tooth over time. In addition to that, we want to clearly see the pulp tissue so we can evaluate it visually. We want to look at it. If carious dentin is in the way, it'll impede us from doing that. And of course, another important reason to remove the carious dentin is that it's impossible to place a direct pulp cap material on top of it. We will never create a seal against infected dentin. We need a clean dentin surface. So once we're confident that all carious is removed, we need to visually assess the condition of the pulp. If we see fresh blood, That, of course, indicates vitality. If we don't see any bleeding at the exposure site, it's likely that the superficial pulp tissue in the area of the exposure is most likely necrotic. Now, if this is the case, the necrotic tissue should be carefully removed with a high-speed diamond burr in water until there is some evidence of bleeding. If we can't induce any bleeding, it should be assumed the pulp tissue is necrotic. And at that point, a pulpotomy should be done and or root canal therapy initiated. Now, I know some of you are thinking, but wait, we did preliminary testing and diagnosed the tooth to be vital. Yes, I realize that. But if you cannot induce bleeding in the pulp after an exposure, you have to assume the pulp tissue is necrotic. Now, there may be some vital pulp tissue apical to it, and that vital tissue may have responded to your vitality tests. But going forward, it is highly likely that we can expect the tooth to become completely necrotic. and eventually require root canal therapy or extraction. All right, so for the purpose of this podcast episode, we do see some bleeding at the exposure site. So now we need to focus on controlling the bleeding because we know that moisture and contamination of the dent will adversely affect the seal between the direct pulp capping material and the dentin itself. Research has shown that a major factor that can affect the success of our direct pulp capping procedure is the extent of pulpal bleeding. after exposure and before placing the direct pulp cap material. bleeding is generally associated with increased inflammation. And in cases of severe inflammation, we can get a reduction of repair capacity of the pulpal tissue. And that obviously is not good for the prognosis. So the prognosis of a direct pulp cap is certainly better in the case where bleeding is minor and quickly controlled versus the tooth that bleeds excessively and is a challenge to control. We'll get more into that in a few minutes. Okay. So how do we control the bleeding? There are a variety of hemostatic solutions and methods that are discussed in the literature and recommended. These include sodium hypochlorite, chlorhexidine, hydrogen peroxide, ferric sulfate, and others. According to recent research and after talking with endodontist colleagues of mine that teach and have practiced many years, a good, reliable, and effective hemostatic agent to use for carriers' pulp exposures is 2.5% sodium hypochlorite. 2.5% sodium hyperchlorite. And that solution can be used directly on the pulp tissue without jeopardizing overall pulp integrity. Research has shown that. Now, in addition to hemostasis, there are other benefits of using sodium hyperchlorite on the exposure site. It acts as an antimicrobial solution, essentially disinfecting the dentin pulp interface. It eliminates biofilm, chemically removes blood clots and fibrin. And it also clears dentinal chips and damaged cells from the mechanical exposure site. So how do we apply the sodium hypochlorite? It's recommended to soak cotton pellets with 2.5% sodium hypochlorite solution. You want to place the cotton pellets directly on the exposure site, making direct contact with the involved pulp tissue. Now, ideally, we should see hemostasis rather quickly when using this method. Within a few minutes for sure. However, if we find that even after eight to 10 minutes of applying cotton pellets, soak with this solution, we cannot control the bleeding. It's highly likely that the pulp is severely and irreversibly inflamed and has undergone irreparable damage. In this case, I recommend looking at root canal therapy as the preferred option. Now, at that time, you might want to do a pulpotomy. and send the patient to an endodontist, or you can go ahead and, if you have time, do the whole root canal, if that's the case. But when you see uncontrolled bleeding for that period of time, the likelihood of a direct pulp capping procedure being successful is very, very small. Okay, so now we're at the point where we've successfully controlled any bleeding, and we have a clean dentin surface. So let's talk about some of the materials we can use as a direct pulp cap. Some of the attributes of a good direct pulp cap. material include simple handling during an operative procedure, adhesion to dental substrate, antibacterial properties, excellent sealing ability, insolubility in tissue fluids, biocompatibility and bioactivity, promotion of mineralized tissue barrier formation, radio opacity, and a material that does not cause tooth discoloration. Now, I hate to be the bearer of bad news, but currently there is no such product that exists that has all those things. None. Now, There are some good ones out there, and eventually there might be a product that has all those things. But right now, as far as the date of this podcast release, there isn't any. However, in recent years, the market has seen significant advancements in direct pulp cap materials. So let's talk about that now. But first, as a dental professional, you spend a large part of your day in the operatory. That's why partnering with the right dental company for the best dental equipment is so important to you and your practice. The folks at DentalEase understand that every practice is different, so they've created a customizable suite of treatment room packages to fit every need. Whether you have lots of room or need to be super efficient with your space, DentalEase has a configuration that will work for you. Known for its revolutionary J-chair and designer-friendly forest equipment, such as lighting and sturdy ergonomic chairs, Dentalese combines comfort, beauty, and efficiency into its state-of-the-art operatory equipment. And when it comes to utility room equipment, nothing beats RAMVAC. It's quiet, reliable, and backed by industry-leading warranties. To learn more about how DentalEase can customize and transform your operatory into one that you'll be proud of, visit DentalEase.com. In previous decades when I was in dental school, calcium hydroxide was the material of choice, and gold standard for that matter, for direct pulp capping material. One of the desirable properties of calcium hydroxide is that it has a high pH, which is responsible for the stimulation of fibroblasts. It inhibits microorganisms' growth. and encourages the healing and defense mechanisms of pulp tissue. The downside, though, of calcium hydroxide is its high solubility and poor adherence to hard tissues. There's no question about it. It does not offer the best seal. We know that. In fact, calcium hydroxide shows a tunnel defect-like phenomenon in the Denton Bridge, although there is evidence that as the bridge gets thicker, those defects go away. But for the most part, calcium hydroxide served As a great material for its time, but there are better products out there now, better materials out there now, which we're going to talk about. So let's begin with MTA, Mineral Trioxide Aggregate. So as an alternative to calcium hydroxide, MTA has gained widespread acceptance because of its potential to promote wound healing of the dentin pulp complex. MTA is mainly derived from Portland cement, as we know, and the main components are tricalcium silicate, dicalcium silicate, and tricalcium aluminate. They also add bismuth oxide for radio opacity. The major benefits include excellent biocompatibility when applied to the pulp wound, superior sealing ability, low solubility, inhibition of bacterial invasion, and MTA has shown to form a pretty solid dentin bridge. In addition, MTA has the potential to reduce the levels of pulp inflammation and hyperemia, which is a good thing. And it has the ability to solubilize bioactive proteins, that are involved in the process of tooth repair. One other point I want to make when comparing MTA to calcium hydroxide, the inflammation induced by MTA is only short-term, which is less severe than calcium hydroxide. Now, MTA does have some disadvantages, such as long setting time, difficult handling characteristics, and discoloration. But overall, recent studies have demonstrated that MTA has a higher clinical success rate and results in less pulpal inflammation and more predictable mineralized tissue barrier formation than calcium hydroxide when used as a direct pulp capping material. All right, let's move on to another material that I think was developed to improve on some of the drawbacks of MTA because this material does just about the same thing as MTA but has... taking away some of those drawbacks, as I mentioned, and that's called biodentine. Biodentine is an innovative cement made of tricalcium silicate that also exhibits very high bioactive characteristics. It was reported that the effectiveness of biodentine in direct pulp capping over mechanically exposed pulps was comparable to that of MTA. Now, biodentine is essentially composed of pure tricalcium silicate, calcium carbonate, and zirconium oxide. And when compared to MTA, biodentine has been shown to have superior mechanical properties, improved color stability, an easier application process, and a faster initial setting time. Now, it does have a few drawbacks. Its main drawbacks are its limited radio opacity, and some users found some difficulty in attaining the desired or optimized consistency. Now, it's been found that the amounts of calcium that are released by biodentine are substantially higher than those of calcium hydroxide cement and MTA. An increase in the amount of calcium released is indicative of an increase in the amount of hydroxyl ions released as well. And that's a very good thing when it comes to looking at the Denton Bridge. It was revealed that when utilized as a direct pulp capping material and permanent mature teeth with... exposure, biodentine and MTA both have favorable and comparable success rates. So if you're using either MTA or biodentine, then you're using materials that are excellent for predictable success with direct pulp capping procedures. Now, I want to talk about one more direct pulp capping material, and that's TheraCal LC. To overcome the shortcomings of the original MTA, TheraCal LC was developed as a modified resin-based MTA. A nice characteristic of this material is that it minimizes the amount of time needed for setting by modifying the powder's composition or particle size. What's nice about TheraCal LC, which is a calcium silicate resin-based material, it can be used both as a pulp capping agent and as a protective liner under your restorative materials. This material is a light... curable MTA cement and is categorized as a fourth generation of calcium silicate material. Now, Theracal-LC has also shown to release calcium ions, which is a key factor in the proliferation and differentiation of human dental pulp cells caused by the material and the formation of new mineralized hard tissues. Now, the amount of calcium ions released by Theracal-LC was in the range of concentrations that could potentially stimulate the dental pulp and odontoblasts, which is the goal, again, in forming that dentin bridge. So when you compare these three materials that I talked about, Theracal-LC, biodentine, and MTA, they didn't have a statistically significant difference in their overall success rate. So all considered calcium silicate-based materials appear to be the most effective type of biomaterial currently employed for direct pulp capping procedures. And these three materials all serve as an excellent choice for direct pulp capping material. Now, it should be noted that the long-term success of a direct pulp cap procedure depends on the severity of the pulp inflammation. the amount of healthy tooth structure that remains, and the durability of the coronal restoration. So obviously, we need to have a good seal in that final restoration. And I do recommend placing a liner and a restorative material at the same visit the direct pulp cap is placed. The idea, again, is to fully seal the tooth and allow pulpal healing. 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