Running Time: 61 min
In this lecture we will describe the relationship of the root canal anatomy to the lesions that are developed at the periradicular area. We will also give all the details how to remove safely different kind of materials like gutta-percha, silver cones, broken instruments, posts and pastes. Details will be given as to avoid any mistakes that would possibly endanger the retreatment perforations and absorptions will be treated in a fast, predictable and simple way.
Release Date: August 21, 2012Subtitle:
Hi. I am in endodontics for 18 years now, and before that I was in private practice for 10 years. So I can highly appreciate when the time comes to retreatment. And I appreciate that because I know the difficulties that colleagues have faced with the teeth that I’m going to retreat before. And because I was in private practice for general dentistry for 10 years, I can see all the difficulties that the general dentists have when they did the tooth. Many times, they do not have the right equipment. And of course, most of the time they do not have microscopes or other equipment that would help to make a nice and excellent root canal. So by saying retreatment, I mean all the cases that the root canal therapy has finished or cases that somebody else has started and never finished because there was a problem. The problem that was either on the tooth at the time that he tried to do the root canal, or a problem that [INAUDIBLE] happened while he was trying to treat the tooth. Many times there is a question, what’s the best instrumental to the perfect work? And over time and most of the orthodontists all over the world, they have their favorite instruments to do their work. Now, is there the perfect instrument? The perfect instrument does not exist yet. But whatever you have in your armamentarium use it and it’s very good if you have the right technique and if you have the right strategies. And if you know the right principles of orthodontics, then even though you do not have the best possible instrument, you will do your job. Like these guys, they do not have the best instruments, but I’m sure that this food will taste good. And this guy has the best instrument, but he is on the wrong way. So the message that I want to send here today is that in life and in work, you will never get the best of everything, but you can always get the best out of everything. And that’s the most important point, and that’s the most important thing I want to share with you in that lecture. Let’s see the first case. It’s a case where we have a periodontal lesion and poorly filled and I tried to redo the case. And when I finished the case, look at this. There are three, four, five lateral canals there, and I was too happy to have this root canal done. But after a while, I noticed that there was a crack on the tooth. What does this mean? This means that unless we have today’s necessary instrument, there are cases that won’t go well because we are not able to see things that we normally see under the microscope. And the microscope in modern endodontics is essential. If you do not have a microscope, please try to have lobes because it’s very important. And of course, if you work under the microscope, having the best possible chair is crucial. If we see in this case, that it’s a retreatment, the previous colleague has found three canals. But if you look carefully here, you will see the fourth canal that is there and was not detected because probably the previous dentist did not have the magnification needed in order to detect this root canal. And if we look carefully, it’s a huge orifice that leads to another canal. And of course, if we fill it, the endodontics will be a successful. It’s very important to get to know the root canal anatomy and to get to know and to work with the x-rays that we see because in this case, we see that there is a periodontal lesion here, but also there is a lesion in the middle of the root and probably this leads to something that we’ll see what it is. It’s very important that before we fill the retreatment, the case of retreatment, we shouldn’t move all the gutta-percha so that it’s there and unless we do that, we’re not going to have the lateral canals cleaned and filled. It’s very crucial to heal lateral canals that we are able to clean and fill because we know that the presence of lateral canals allows the movement of bacteria from and to the periardicular tissues. And this has been shown by many authors long time ago. We very well know that successful endodntic treatment is achieved after obturation of lateral canals. And this is because the lateral canal is a canal. It’s a canal that contains polyp tissue that most of the time is inflamed and we have to clean and we have to fill, otherwise, the inflammation will come back. When he have furcation involvement in many teeth, we many times wonder if this case is endo or perio. We know that we do not talk and we do not mean one canal. Most of the time, we talk about root canal system, and that’s very crucial. In this case, we see that there is a furcation involvement and we have a lesion in the furcation area. We do not have any lesion at the periardicular area, and we’re always wondering if this is a case of perio or endo. Most of the time, we would say that this is a perio case, and we would treat it as a perio. But in this case, even though we were not able to remove one of the mesial silver cones, we’ve got two lateral canals here and when I saw this, I was pretty sure that this case is going to heal, and it really healed. So in this case, we understand how the lesions work. Everywhere that we have a lesion, we have a portal of exit of bacteria that create that problem. In this case, we do not only have a periardicular tissue, but we have a lesion all over the tooth. So the very first thing that we need to know in this case is, and the first test that I’m doing in this case is probe. If I say that there is a huge probing, then I understand that probably it’s a crack. But in this case, there was no probing, so I went ahead and I did the retreatment. In this case, it is very important that you remove all the gutta-percha without using any solvents, because the solvents will dissolve the gutta-percha and probably will fill all the lateral canals that exist there. So that’s why we avoid to use solvents in retreatment cases when we have lesions that are in the furcation or caught on a limb of the teeth. And this case healed beautifully. It’s bone all over and it’s a recalled case of six months and the patient is happy, and we are happy. Sometimes when we have silver cones or other materials that we probably do not know what they are, we have to do our best. Let’s see this case. We have a bit of a visual lesion, and then we have a furcation involvement. Probably, there are no pockets, so we go ahead, retreat the tooth and probably, it will heal. In this case, what I expect is that probably there is a lateral canal here. And after we remove some of the gutta-percha, cone fit, yes, there is a lateral canal. In this case, when that was a colleague that came over to me and told me that A, that’s my mom’s tooth. There was a sinus tract, and I put some solvent there, and this is the second x-ray that I took. In the second x-ray, you will see clearly that by using the solvent, the lateral canal that was there was filled with gutta-percha. It’s very difficult now have the sodium hypochlorite to get over there and to clean that space. So this case is prone to fail. When we have a case like this and we are not able to remove the silver cone, we have to do the best that we can. And the best here is that we do our best. We tried to overpass the silver cone. At the end, we were able to fill the canal even though the silver cone is there. Many times, we consider that if we have foreign bodies in the tooth that prevent us from doing the ideal work, we think that the case won’t work well. And sometimes, yes, it may happen, but many times, this is not going to happen. And if we clean well and if we give the appropriate time for the irrigants to work appropriately, then the case will heal. And in this case, it healed nicely. In this case, we did not have a lateral canal here that we can see. Many times, we cannot see the lateral canals because they are tiny. And we cannot see them filled, but if we do the right work and if we let the irrigants work for a long time, then these spaces will be cleaned and will be filled by little sealer that it’s enough to work and do a nice work, and the body’s defense mechanism will take care of it. If we look carefully, we see no bone between two roots of the tooth, and also, we have a periodontal lesion. Many times I would consider that this case is lost. But this lady wanted to keep her tooth, so I probed. There was no probing, and at that time, I decided that I will go ahead and do the retreatment. That’s the working length fill. And then I started to clean and shape. But after a while, I had an accident. I broke an instrument in the canal, and I was not very happy for that. Two reasons. First, I broke an instrument, and second, the instrument was not going at the end of the root. Because there is a chance that sometimes if you clean the canal appropriately, you my have a case that will heal. And the other thing is that the other mesial of this is the mesial buccal and that’s the mesial lingual. I mean, I wasn’t able to get down to the mesial lingual. So we have two problems here. One is broken instrument and the other is that, I mean, I cannot clean and shape the mesial lingual canal. I finished the case. Here is the broken instrument. Here is the mesial lingual canal. I didn’t like it at all. I was pretty unhappy with it. I was not paid for that case unless the lady comes after six months and we see clearly that the case was healed nicely. What does this mean? This means that sometimes we will do mistakes, sometimes things will happen. But if we have the right principles and if we use the right techniques and the right strategies, yes, we can get results that we do not expect. That’s a huge lesion. And of course, this huge lesion came from these 1 and a 1/2 millimeters that were untreated. This root canal was done 10 years ago, and the patient presented to me with the demand of doing a surgery. I told the patient let’s try to retreat this tooth and then treat the other tooth because it responded necrotic, and then let’s wait for a while before we do the surgery. This was the case when I finished the root canals. And the patient comes after 11 months and look at this. It’s bone all over. Long time ago, we used to surgerize these kind of lesions because we felt that there are too big for the body defense mechanism to heal. But let’s give it some time. It was 10 years there, so another six months, it wouldn’t make a big difference. When we tried to retreat some cases, it’s very important to understand what happened before the dentist in order to fill short. Many times, a dentist fills short because there was an obstacle there or he leaves the canal or the canal was broken by somebody else. So when we retreat these kind of cases, we must take care of many things that we need to do during the retreatment. And the very first thing that we need to do is, that we remove just a couple of millimeters initially of gutta-percha. And after that, in this case, we use solvents. Chloroform is OK, whatever solvents you have. We use solvents but trying with a very small file, #10 or 15 to overpass that obstacle. Because at this point, the canal probably was blocked, and if we’re careful enough, we will be able to redo this root canal. This case was done by somebody that believed in filling short. The patient was having symptoms and came to my office and asked for retreatment. I was surprised that the tooth was filled so short, and at that time, I expected that it was not the retreatment or the problem but it was some other anatomy that created the problems. And if you look on a different angle, you will see that the lateral canal wars larger than the main canal. So it’s very important that we have to take care of teeth and we have to take care in a very nice way and do not use a lot of solvents, otherwise, these lateral canals will be filled by gutta-percha. This canal, the mesial buccal canal, was blocked. And when I took the x-ray, it was blocked just in the middle of the canal. At this time, the only thing that we can do is that we enlarge the coronal in the middle part of the tooth. And let’s say that we measure that the length of this file was 18 millimeters. Then what we do is that we try to clean and shape this canal up to 17 millimeters, means 1 millimeter short. And if we create enough space, then after a thorough cleaning using EDDA and sodium hypochlorite, then we take a #8 or 10 file, we bend it a little bit and then there is a good possibility that we will overcome the leads there. And we will be able to finish the case nicely. And we had a couple of lateral canals in this case as well. This kind of retreatment is very challenging. And it’s very challenging because if you look carefully, you will see that this canal bends, curves to mesially. And this root canal was done straight. This means that at this point, there is a good possibility that we have canal transportation and that we have blockage of the canal. That’s why we do exactly the same thing. We remove the gutta-percha up to here, 2 or 3 millimeters below the orifice. And then we use solvents and we use #10 or #8 file, we bend it a little bit, and then we are trying to go around the blockage. And if we are lucky enough, we will get through even though it is very difficult and sometimes it’s not going to work no matter what we do. And if it works, it will work nicely. We have a couple of lateral canals here and there, and I was pretty happy with the result. That’s another view. Sometimes when we have large lesions and then we have probably this is gutta-percha that is outside of the canal, then what happens here is that many times, many colleagues would consider that we surgerize the case. We may not be correct on it. Is it the best way to go? Personally, I would love to have a cleaned canal and after that, if the case won’t heal, to go for the surgery. And the reason is that most of the time, these cases are very inflamed, and they have a lot of bacteria in the canal. And I do not want to have bacteria in the canal. And even though I have removed the lesion there and I have done a good root and filling. So I prefer always to have a cleaned canal, which is some sealant, the gutta-percha, it’s over there. And you see that the lesion is quite big, but after some time, it’s bone all over, and that’s the most important thing. If we try, this was a case where I was not sure what should I do because we have two big problems here, one is the post, trying to remove the post, sometimes it’s dangerous because you might create some cracks in the tooth. But the other thing is that this gutta-percha, that’s a huge gutta-percha and here, we have a canal that is absorbed. So in this case, there are two problems that I have to consider for my treatment plan. At that time I decided to retrieve the case. And what we do in this case is that after we remove the post, it’s very good if we place there a Headstrom file, twist the file, but the Headstrom file should be a lot smaller than the gutta-percha. And the reason I say that is that if the Headstrom file is as big as the gutta-percha point, it will push the gutta-percha to the periardicular tissues and I do not want intentionally to do that. Sometimes we may have some sealer outside of the canal. I don’t care. But if I have a gutta-percha point there, I don’t care unless as the previous case. I don’t care, but I would love to take it out. That’s why we placed there a Headstrom file, twist it, and that’s the result, and I was pretty happy for that because now, we can do a nice job, and it will work appropriately. When this case presented to me, there was a sinus tract and I saw that there two points of gutta-percha over there. I always want to take two x-rays in these cases. In most of the cases, I need two x-rays, two x-rays with a different angle. Why? Because in this case, when I took a second x-ray, I realized that one of the gutta-percha cones was outside of the canal. And what happened was that the previous dentist perforated and filled the bone as a canal. Now, the difficult part in this retreatment is to get this out. Can we do that? Sometimes under the microscope, yes, we can do that. And we can do many more things. In this particular case, I was able to remove the gutta-percha from the bone and then to find the canals and fill the canals, and then fill the perforation with composite. And that’s what we do in these cases. There are many systems outside there that we can use in order to remove the posts. This is one of them. And in this case, there are trephines that we can put on the hand piece, slow hand piece, and make some grooves around the post. And then we a key-like instrument that will unlock the post. And that’s a very good system. Also we ultrasonics to remove the instruments, and we use some nickel titanium ultrasonic tapes in order to remove the cement that is around the posts. And it’s very important because if we remove a lot of the cement around the posts, then we will vibrate the post and we have many chances to remove it. This is a Stropko Irrigator. We need that because when we work under the microscope, we have to have something that is very small to get into the canal and to dry the canal after we work sometimes. These are carbon post. This is actually porcelain posts. And these were broken at this point, and it was pretty difficult. But if you go around with this night-eye ultrasonic tapes, you have very good chance that you will remove them. Use ultrasonic there’s around the post, remove the cement, and then just hit these posts on top of that, and maybe, if you’re lucky enough, they will come out. Now, we have two cases with two posts there. This is more difficult to remove it, and what we have to do is that we have to take a very tiny round bur and to remove some of the dentin that is around the post. Then we will separate the post from the dentin, and we have to remove just a little bit of dentin because that’s very crucial. We need the dentin to restore the tooth. So as much removal of dentin as possible, then we can remove the posts. This is a big post. And the main problem that we have when we hit this post with ultrasonics is that we may create a crack on the tooth, and that’s something that we do not want to do. In this case, we have two posts there, and there are posts that have been done in a lab, and they are very difficult to remove. It takes time, but if you have a microscope and you remove very little of that dentin and then you hit without ultrasonics then you have the opportunity to remove them. Look, we have a very big lesion there. That’s the cone feet. That is the final fill at that time. You see the lesion here and there. And that’s a recall after two years. Here, we have two problems, one is to remove this post because it’s screwed there and the other is that it’s obviously the canal was transported. And now we have to find the canal and then see what we’re going to see after the fill. Not only we found the canal, but here, there was a lateral canal that was filled as well. We see that we have in this case a broken instrument outside of the canal. I don’t know how this instrument went there. I mean, I cannot see another fill, but it was there. Do we extract these teeth? It’s better if we have a good fill. And if you’ll notice at this point, there are some spaces that were filled. What does this mean? This means that if we use the appropriate operating techniques, then we fill all the space. And the case healed nicely after five months. In this case, it was only the distal canal was filled. The mesial canals were not found at that time. We have a big lesion. And with the retreatment, you see that we have a delta here, and I want one more time to tell you that it’s very important that we use during retreatment, we use passing techniques, otherwise, it’s very easy to transport the canals or to fill the lateral canals with gutta-percha as I mentioned before. In this case, we have a broken instrument here, and we have some materials that we do not do really know what they are. We were able to overpass broken instrument in the distal canal. But the mesial canal was filled almost in the middle of the root, but the case healed nicely. That was a recall of five months. When we try to remove the silver cones, there are some things that we have to take care of. First, we cannot hit with ultrasonic tapes the silver cones because they melt. So it is very important when we cannot get these out with special hemostatic pliers. It is very important that we remove some dentin around the silver cone, and we remove if we are able, we remove gutta-percha if they have gutta-percha there. So we use some solvents to dissolve the gutta-percha, and also, we need to create some space around the silver cones. And if we do that, then what we can probably do is that we either place there Headstrom file, twist it, and take it out. Most of the time, the silver cones will get out. And then we will be able to fill nicely our case. If you look, that’s a big lesion, and we have two teeth here. It’s a large lesion. And this lesion is very close to the nerve. It’s been there for 15 years probably because this root canal was done 15 years ago, and now we have a large lesion that includes both teeth. And notice that this is a part of silver cone and it’s here at the bottom of the lesion. When we remove the silver cones, this is the final fill. Look at the sealant here. And that’s the cone fit. Look how big the lesion was. And after a year, the lesion has been healed nicely. But notice that the silver cone was at the bottom of the lesion and now it moved up. As the bone healed, it took the silver cone closer to the tooth because it healed all the time. It healed from the periphery to the center of the lesion. This is one of my favorite cases, case that taught me a lot. And this case taught me a lot because we had silver cones here, and when I tried to remove these silver cones, it was impossible to remove these, impossible. And when I took the working length fill, I was not very happy because I fold that the exit of this canal of the distal canal, distal canal was there, in here. So I filled the case of that time, and all of this space was filled gutta-percha and sealer. It’s a big lesion. I told the lady to go to the dentist and restore temporarily the tooth and to see what happens. I didn’t have much expectations. The lady comes after a year without even having the temporary filling on the top of the tooth. When she told me that at that time, I was pretty sure that the lesion would be a lot larger and the nerve was close there, and I worried. So I took an x-ray. I didn’t expect that. The case healed nicely even though the tooth was open to the environment for a year. I didn’t expect that because we all know that coronal liquids is very crucial for the healing of the endodontic treatment. In this case, not only we have a silver cone here, but we have another little thing here that I do not know what it is. And we have a lesion there. The root canal anatomy, most of the time, will surprise us, and I was pretty surprised with this root canal anatomy and the spaces that were filled. Large lesion. I expected that there was a perforation here. Fortunately, there was no perforation. But again, the silver cone would not come out. The distal canal was filled nicely. It’s a large lesion, and it healed after six months. We have furcation involvement. And in these cases when we have furcation involvement, then I would consider that as a perio problem. We have here a broken instrument probably and two silver cones and poorly, very poorly-treated distal canals. The broken instrument is still there, and I was pretty happy with the result. We got a lateral canal on the distal and a lateral canal on the mesial on the second molar. After a few months, we see that the cases were healed nicely. When this lady came for retreatment, I told her that yes, we can retreat the tooth, but at the same time, we have to do the surgery, because there was 2 or 3, maybe 3 or 4 millimeters of root canal that was not treated. So I did not expect just to heal with root canal retreatment. So I did the root canal. I finished the root canal, and I scheduled the lady next week for the surgery. Something happened, and the lady came after three months for the surgery. She was scheduled for the surgery. And I said, let’s take an x-ray now to see what’s going on there. Look at this. It healed nicely. We cancelled the surgery because within three months, we had a very good bone healing there even though this part of the tooth was untreated. We have a lesion here. Probably there is a perforation there. This tooth was perforated and was left there. We find the root canal, and that’s very important. We do the root canal treatment on the main canal, and we fill it from here to there about the last 5 millimeters, and then we tried to take care of this. So we fill the canal, and then we fill the perforation or the absorption with MTA. This was done in one appointment. And that was the recalled case after five months. Everything healed, then the dentist had placed there the post and the crown. 15 years old. 15 years old, and I was not happy when I show that big of perforation. It was a perforation that was done by the dentist that referred that case to me. And she told me that we have to save this tooth because he’s 15 years old and I feel so guilty for him. And that time, I was wondering what we can probably do because its issue is perforation. At this time, I decided to do the root canal first, finish the root canal, leave post space here, and at the same day, I filled the perforation with MTA. it was very difficult. First of all, in this case, you have two rinse the bone with saline in order, if you notice, to remove all the stuff that is in there, because we need to help the body’s defense mechanism to work faster and more predictably. So you rinse with saline, and then you fill with MTA. That’s another view. I left some post space here. Five months later, you see bone all over. And that was very nice restoration though filled with composite everywhere, and it healed nicely. This amalgam unfortunately, was not either buccally or lingually. So when I accessed the tooth, I realized that the previous dentist had made the perforation there and not only that, he filled the perforation with amalgam. It’s very difficult to remove the amalgam. It was right on the bone, and the patient was in pain for a long time. I accessed the tooth, removed the amalgam, rinsed it with saline, and then I tried to find the root canals. Very difficult because the canals were calcified. Then what I did is that I placed a file on the distal canal. And after that, I filled the perforation with MTA. I cut the file. I placed some temporary filling in the tooth, and I showed the case after two days. I did that because I left the file because I did not want the MTA, after it sets and it expands, to fill the orifice of my distal canal. And I tried to protect that, the distal canal. So I left the file there with MTA for two days. The patient was out of pain the next day. And here it comes, and I finished the case after two days. And this is 11 months recall. The most important thing is that the patient was out of pain in one day after placing the MTA and cleaning. When I show that case, this lady is a doctor in a hospital, and she said, I do not want to lose this tooth. Do whatever is possible. I do not want to lose the tooth. At that time I said, we don’t have many chances, and we do not have many chances because it’s difficult. There is a canal transportation here. There is a perforation, and probably, the canal was blocked at this point and also was not only blocked, but probably was filled with debris. So I thought at that time that it was almost impossible to get down to the canal. First of all, I tried to stop distal working length until the place of the perforation. And then, after long time, I managed to do that. I mean, I knew that it was difficult, but she was a very nice lady and she insisted. She said, again, after half an hour off working with the tooth, please, I want to save the tooth. And then I spent another half an hour, and look at the result. Again, I mean, it wouldn’t work. I was not sure if it would work, but it did work. And at that time I was pretty disappointed. And I told her that probably it won’t work. And she said, that’s OK. If it doesn’t work, we will extract the tooth. And then I said let’s make another effort, one more time. One more time and it was there. Lucky. I was lucky enough. I was there. I filled the case with MTA, and again, I left the file in the canal for two days. Before the case came back, after two days, I found the canal again, cleaned, shaped, filled, and this is a recall of six years. It has lamina dura all over, and it healed beautifully. She’s a lawyer. She’s a lawyer, and she comes to my office and she said, two endodontics recommended extraction of the tooth. What do you think? At that time I said, I think that we have 10% chances. And she said, 10%? 10% too many. Let’s go ahead and do that. I was surprised. I didn’t expect. Actually, I did not want to do that case because we had one, two, three broken instruments and two perforations there. And I said 10%. I was thinking at that time that if I tell her 10% chances, then she would say no, but she said yes. So I had to do that. In these cases, what we have to do is one thing at the time, focus every time on what we want to do, and do it. I removed tooth instruments. The other instrument was left there. I took an x-ray, and then finally, I was able to remove all the instruments. So one at a time. Fill the canal was very difficult. And at that time what I did was that I left the file there. I filled the two perforations. I removed the file, and then I told the patient to come for the next appointment after a couple of days. So after a couple of days, she comes, we take the working-length fill, and this is the final fill and the two perforations that were filled. Notice that there are lesions all over the tooth. This is 11 months recall, and it shows excellent healing. 65 years old. He said, I’m not going to lose this tooth. I told him that, yes, you’re going to lose this tooth, because I mean, I can’t do anything. I mean, the whole distal root is absorbed. And he said, do whatever you can, and I won’t blame you if I lose the tooth. I insisted, and I didn’t want to do that, and he insisted as well. He was a very gentleman. And I said, OK, I’ll do that but remember, you will never blame me if I fail. And he said, I won’t blame you, doctor. I was trying to remove all these different things that were there, silver cones, paste dust, everything. that was the case, and finally, I was able to remove most of them. And then at that time, I filled the canal with MTA, and I left post space. Now, there are some things that we have to take care when we do this kind of work. And first of all, we have to think that outside of the canal, there are liquids all over the periardicular tissues. The periardicular tissues are filled with liquids. And the liquids are not compressible. This means that if we place the MTA there and we do not accept a lot of force, and we use some paper points and cut on pallets to absorb most of the moisture from the MTA, then the MTA will go nicely because the MTA needs good handling and very little force. So in this case, I placed the MTA there, and I pushed the MTA with paper points. Paper points and I was changing again and again the paper points, and I just wanted to absorb as much water as possible. And that was the– I mean, I was impressed. I did not expect that. And that was a sinus tract, that tooth. And this is four years recall. It looks nice, and it’s bone all over. And this is the case, and the patient is so happy. And all the time, at least twice per year, he brings me something. And I really love this gentleman because sometimes, the patient will force you to do things that you do not expect. I refused to do this case as well. This gentleman, he was 62 years old. I wanted to keep the tooth, but there was no tooth around. There is a huge resorption, and in this case, when I access the tooth, I tried and I removed all these gutta-percha and sealer that was there. And the tooth was bleeding a lot. I took an endodontic spoon, and I removed all the inflammatory tissue under the microscope that I could see over here. And after a while, the bleeding stopped. And I placed calcium hydroxide. We very well know that calcium hydroxide kills bacteria and neutralizes the endotoxins. And that’s very crucial. Initially, I was removing the bleeding with this little surgical section. And at that time, when you place the calcium hydroxide there, then on the top of that, you use either large, very large paper points to absorb some of the water that is in the calcium hydroxide, or you use cotton pellets and you plug the calcium hydroxide with a plier and a cotton pellet. This helps a lot because most of the time the cotton pellet will absorb the water of the calcium hydroxide, and the calcium hydroxide will stay there for a longer time and will have better results. That’s how it looks. It looks pretty dry after a while, and that’s the calcium hydroxide there. And then after four months, the patient comes and it’s ready. There was a sinus tract there, and it was gone after a while. But now, we cannot fill it with gutta-percha in there. That’s obvious. At this time, there was no bleeding. I was able to dry the canal and fill the canal with MTA. This is 11 months ago, and you will notice that there is lamina dura around the tooth, and I that it’s bone all over. And this is the tooth that we worked on. And he was very happy. The message that I want to give you today is that, all the time, try to do your best, have the right instrument, but above all, try to remember that the only crucial thing that you have to get to know is the motivation that you have for your work and how much you love your patients. Because most of the time, it’s them that will give you the motive to do the right work and to be as excellent as you can. Thank you.