Diagnosis and Treatment of Referred Dental Pain

Referred dental pain can be difficult for practitioners to diagnose without an understanding of the cause of dental pain and how teeth respond to different pathologies. Referred dental pain is caused by real symptoms that need to be treated, and in this episode Dr. David Alleman discusses types of referred dental pain, tips for diagnosing cracks under restorations and procedures for eliminating post-operative sensitivity through biomimetic restorative dentistry.

Article referenced in this episode:

Brannstrom M. The hydrodynamic theory of dentinal pain: sensation in preparations, caries, and the dentinal crack syndrome. Journal of Endodontics. 1986;12(10):453-457

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Transcript

0:33

Well, welcome to season three, episode nine of the Six Lessons podcast. Very excited to talk about a topic that is important. And that is how the brain interprets pain. know, there's a saying that says no pain, no brain. We talk about pain every day and patients come in with some pain symptoms. But when a patient says they're in pain, it can mean many different things. If a person is swollen up and you know their eyes are closed, obviously that type of intense pain of a very bad abscess is very different than a patient is biting on something and feel something, and they interpret that as pain. And so if there's a pain gradation of 1 to 10, then usually dentists are dealing with something in the below five level endodontists Quite often get the above five level where you have a necrotic pulp and it's hurting without doubt a lot. But when a patient, is asked in a routine examination using the six lessons approach, do you have any pain symptoms? We're looking for pain on biting. We're looking on pain on cold, responding to something's cold. And we're also looking for a sensitivity to sweet. So if somebody needs something sweet and they report they feeling something, they quite often will not refer to that as pain. But they'll call talk that is sensitive. Okay. Same with cold. mean, I've had a patient a young patient and just in their early 20s saying I never eat ice cream. that's a that's a symptom that I'd like to cure if I was, if I had that. But her report was that every time she ate ice cream, all of her teeth were sensitive to the coldness of the ice cream. That's kind of an extreme. But the idea of this pain sensation when you're feeling pain in your teeth, the teeth have certain connections to the brain that are usually connected with the sides. And so your brain will feel pain on the right in the left side of the brain, and feel pain on the left on the right side of the brain. So the crossover and as you have those large what are called trigeminal nerve, branches, there's three main branches is called the optical branch. And then you have the maxillary and you have the mandibular branch. So these two branches of the trigeminal nerve give the brain everything it needs as far as signals of pain. But there is a little bit of a problem if one nerve is innervating a whole quadrant of teeth, which on the bottom would be seven teeth on the top would be seven teeth then those teeth, as they have seven nerve bundles coming, out of the apex of the tooth into one of the branches of the trigeminal nerve. When it goes into the brain, there is a phenomenon that is called referred pain. In other words, there's a little mix up on which tooth is coming from. Now, the referred pain is usually in a quadrant of tooth next to tooth. For example, two months ago, actually, I had a little pain on biting on my left side. I was able to identify that as coming from the top. So the top left quadrant, when I bit on hard things, I had a particular time when I felt something and ooh, I felt like that hurt when I bit down. So that pain on biting that I had the only way I can really get the diagnosis of that is to have a dentist make the diagnosis, and hopefully the dentist has an idea of the risk assessment that we teach of one, two, three, four. That gives us an indication. Is there a crack in enamel that may be a crack into dentin? The way we differentiate a crack in enamel, particularly on a marginal ridge, as going into deaden is we asked for sensitivity to sweet or cold that will usually give us the first indication. But then we ask them, do you have pain on biting? And so these early cracks that go through the day will have some, but they won't have a symptom of what we call pain on percussion. In other words, every one of your teeth that you can bite on is not percussion sensitive, which would indicate something happening at the apex of the tooth. And so in this diagnosis, my son was my dentist, when I came to the dentist last week, and he made the risk assessment that I had two marginal ridges that were fracture and the two marginal ridges were on the bicuspid and the second molar. But my perception of my pain was on my first molar. In other words, somebody asked me, okay, when you bite down, where is the pain coming from? You know, I say, I feels like it's the first molar, but all three of these teeth had composites that were over 20 years old. Now, if a composite was done 20 years ago was my three were they were replacing amalgam restorations which were replaced. 50 years ago. And so the amalgam that lasted for 20 years, over 20 years, and the composite lasted over 20 years, the actual amalgam didn't break, the actual composites didn't break. But what was happening that had me changed my amalgams into composites, and then my composites now had to be evaluated for what was causing their pain. And amalgams, of course, are not connected side to side. But if you have a certain isthmus width which is two millimeters or greater and a certain cusp width that is three millimeters or less, then the science shows us that the movements of these teeth, where the teeth are moving in two different directions, or a composite restoration bonded to one side of the tooth, is moving independently of the unwanted side of the, tooth. And so, quite amalgam moves in two different directions on the side of the unbonded filling in the middle, where a composite will usually fail on one side. And so the composite and the rest and the tooth will move in one direction, and the remaining unbonded tooth will move in another. But both of these situations allow a biofilm to form of about 200 microns, which allows decay in these gaps or cracks, which is called occlusal effect carries. But also the science tells us that if we have a movement of around 175 to 180 microns, then we will have enough movement to initiate a crack which will continue to propagate upon further occlusal stresses. The the force of mastication. So the dentist who's trained in these concepts and this science will understand that if an isthmus is wider than two millimeters, which all of my three restorations were, but the smallest restoration, which is right at two millimeters, was my bicuspid, the larger isthmus of 3 or 4mm on my first molar and second molar had been bonded with a dentin bonding system 20 years ago. So we call that adhesive dentistry. But they were not stress relieved with technique. So we would call biomimetic. So I was aware that these restorations were probably not going to be permanent. But again, I'm busy with my life for 20 years. And after I got my amalgams replaced by composites by Mark Christiansen, my dentist at that time, an adhesive dentist of of good technique and good materials, but not a biomimetic dentist. There weren't any biomimetic dentists. Well, I was getting there, but nobody was getting taught biomimetics until 2003. And these were done before 2003. But the idea is that I knew that these were at risk now of, of de-bonding. But I suspected that the first molar would de-bond first, and that would be where a crack would happen, as it turned out, because we had a risk of decay or fracture on all three of these teeth using the one, two, three, four, we had isthmuses that were wide. We had marginal ridge fracture on two teeth, and we had a cusp that was less than three on on the molars. All three of these teeth were at risk, and all three of them responded positively cold, which was good. That's the first thing that every risk assessment should, should do use a cold test with ice or endo ice to see if we have a vital pulp or how the pulp is responding. And so, as Davey tested my three teeth, all were responding positive to cold. we knew that the only way to see where the crack was, was to remove the restorations. So I made the decision. I wanted to be proactive. And, if I couldn't tell exactly where the tooth was, painful. Then we would take the restorations out to look for the cracks. Now, some dentists will use what's called a tooth sleuth to try to decide which tooth is sensitive. It's not, a bad approach. you use a to sleuth and you bite down and it causes pain, then that actually is a slight propagation of the pain. So the crack is a little bit longer than it was before you use the tooth. if you don't have a consistent pain on biting, that usually means that your crack is smaller. If you have a consistent pain on biting, that means the crack is really long. You're definitely going to have to do something, immediately, but I didn't have that consistent pain on biting because I had a small crack and a couple of months ago, and it's propagated now. You have a little bit of, creation of secondary dentin from that stimulation, and you can have a little bit of re mineralization on the top. And so Martin Brannstrom in 1982 and he wrote the definitive book on cracks in crack propagation. So recurrent symptoms are what, is the pathognomonic diagnosis that if you have recurring symptoms, it's a long crack if you have symptoms, but they go away. It's a smaller crack. If I would have done this, I think I could have, narrowed down which teeth were were cracked and which weren't. But if I have a risk for decay and I have a risk for fracture, then all of a sudden it's like, I don't want decay or fracture in any of my, teeth that have restorations. And I want to be proactive. I want to find out early and treat them early, because I'd like these restorations now to be permanent. And if you're 73, 74 years old, you have a good chance. The 20 or 30 years will be all you need. the idea is that, when we took out these three composites, were all three were occlusal. peripheral rim fractures, became obvious, and decay on my first molar was underneath the restoration, but no cracks. No, the decay showed that there was a small crack at one time, and that caused what's called the occlusal effect caries. So I did have an old crack on that first molar that became carious over the years. And that was the problem on the first molar. But it was not the problem that was causing the pain. By adding the new cracks that were felt by myself a couple of months ago, they were on the bicuspid and the second molar, but the cracks were not deep and one was horizontal, one was vertical. The vertical, which was the smallest, was actually, the one on the second molar. The horizontal, which is a little bit larger, was on the bicuspid. And usually if you have a horizontal or an oblique fracture, you have more surface area that can have pulpal fluid moving as the crack is coming off and filling with fluid and coming back. If you have a vertical crack, then both sides have fluid and the movement movement is in the middle. You will have less on an early vertical crack, you have less symptoms, but if you have a little more advanced horizontal crack, you'll have the more, more pulpal movement. And the pulpal movement, is the source of the pain. So the hydrodynamic theory of pain that Brannstrom talked about, 1982, 1986 wrote the classic articles and book that, symptom of recurring pain on biting is what most dentists should have, in use in their office. still, if you want an early crack treatment, particularly an early vertical crack treatment, which are the most likely to kill the pulp and to crack a root, which would make it catastrophic in its propagation, and you would lose the tooth. Then you need to have more sophistication to realize that there's a difference between a horizontal or oblique crack, a vertical crack, a small crack, a large crack, all of those things we teach in the lesson. Two of the six lessons approach. Anyway, end of the story is we got the cracks dissected one vertical, one horizontal and had the occlusal effect caries removed. Davey created the biobases on all three of these teeth. We had an inlay on the bicuspid on the two molars. And they were cemented the next week after the biobases were placed. I didn't have a temporary around. Those three bio bases are totally comfortable for chewing. You just have a little bit of food, accumulate in the area that the enamel replacement onlay hasn't been bonded. But after you bonded the inlay on the bicuspid and the onlays on the molars. Totally satisfactory. No pain on biting. I been given a good workout last couple of weeks and they they feel great, but the referred pain on an arch very common. Now let's talk about another type of referred pain. And this is also a personal story of myself. When I was in dental school, these amalgams that I had placed when I was 19, when I went to dental school, I was, 24 years old, The amalgams had been in place for five years. But I had some pain on bonding on my right side. And so I'm in dental school. Cracked tooth syndrome was talked about, but I did not have a repeatable pain on biting on this. Right side. But by the time we had an X-ray taken and a faculty member looked at my teeth on the right side. They didn't see anything. Amalgams. There was no recurrent decay visible on X-rays, which is kind of the standard that was used 1975, 1978. really didn't have a discussion about cracked tooth syndrome that I can remember. And because it was my own tooth, I think I would have remembered. But anyway, X-rays are taken. They didn't see anything. Okay, fine. move on with your life. I went into the Navy for three years and as I came out, lived my life doing traditional dentistry, became frustrated, obviously, but then was introduced in 1995 to this adhesive dentistry. And that's when I had my amalgams removed and I had, my friend Mark Christiansen take all my amalgams out and put in composites and the three composites I had done, a few weeks ago. They were done the same time as these composites, were done in 1995. Anyway, they're probably over 25 years old. But, when I had these replaced, 25 years ago, they were going good, except on the right side. Now, a few years later. So this was, 2005, about ten years after they were replaced. I started to have symptoms on the right side. Now, in 2005, I had already been teaching dentists how to dissect cracks for two years. So I was pretty happy that now I could diagnose myself. And because in 2005, I only had two doctors that were trained and neither one of them had microscopes, you know, and I knew how difficult it was because I've been using a microscope for five years from 2000 and 2005. But anyway, I, decided to, diagnose my cracks myself. And I was diagnosing pain on my first molar on the bottom. And, I told my assistants, okay, we're going to do this restoration. Because my doctor. Doctor, Mark, who hadn't been trained in six lessons, Mark Christiansen, but it was on Christmas Eve, and anyway, he wasn't available. So I told my assistants, okay, give me some anesthesia. Gave myself a block left handed. That's pretty good, right on my right side. And I've put a rubber dam on and I had an intraoral camera. I could take snapshots of the tooth, look for cracks. They had a mirror so that I could use my handpiece through the mirror to take out the, composite restoration and, lo and behold. I found the crack in my lower first molar. And lo and behold, I had the skills to be able to dissect it very slowly. So I dissected the crack on the lower molar, Used caries detector dye to see if there recurrent decay. I don't remember if we had, any occlusal effect caries. I don't remember that. But anyway, we had the tooth caries free. Crack free did our bio base. Our immediate dentin sealing, after air abrasion, did our resin coating, did a little marginal elevation, did a normal bio base, took an impression. And then, I made a chair side semi direct onlay and then bonded that onlay have never had pain on that lower first molar onlay for. five. So that's 20 years okay. So six years ago, out of the blue, I was lecturing, I was traveling to different dental conventions. I was in Spokane, Washington, and I had a piece of composite and a little bit of tooth break off my upper occlusal composite that, had been done 95, 96 but I had no pain and I was busy. So I went to the Kuraray booth and got a little composite, got a light, did a little patch up, assumed that it was just an enamel fracture and everything was fine for several more years. And then four years ago, half of my upper first molar broke off. I mean, a big piece including, part of the, mesial root, mesial-buccal root. And I could see that the pulp chamber was dead. The tooth was dead, obviously, if it hadn't had a fracture that was vertical, that split the tooth in half, I would have, had it restored to try to connect it side to side after I had done a root canal. But this upper molar, the pulp had done without extreme pain, and eventually that tooth was lost. So I don't have an upper first molar So thinking back in my mind, I probably had referred pain from the bottom, which definitely had pain when this was, treated by myself. In that, 2005, 20 years ago, because I had a repeating pain on biting on that tooth. And that's why I treated it myself and successfully. No pain for ten years. But then when I started to have a failure ten years later, it was on the same tooth on the top. And so the referred pain that we talk about were in one quadrant. You can't tell which tooth it is. the referred pain top to bottom is reality. That's been documented. Also because you have these nerves, trigeminal nerves are separate. But then right before, the three branches, that's why they call it trigeminal. Three bodies. The three big nerves come together into this foramina that is going into the brain. And there is some crossover, particularly between these branches of v2, v3. So we call it V because v is fifth cranial nerve 12 cranial nerves. And the fifth is the trigeminal nerve that has these three branches. But this crossing over of these paid receptions before they get to the brain can make it very difficult to know if you have pain on top or on the bottom of a tooth that's, close to each other, this anatomical relationship. So, you have pain on the top, it can actually be perceived as pain on the bottom. If the pulps, particularly on the bottom because I did have cold tests on this bottom before I treated it. Still, as far as I know, the nerve is still functioning, with blood vessels and nerves, connective tissue, fibroblasts, all the things that are in the connective tissue. But the one on top that had the bigger crack, or I should say the more critical crack, because the one on the bottom, the crack, seemed to be going a little more. I only had I actually did an overlay, so I had onlay all the cusps on the bottom. as I dissected the cracks, if the crack went, I can't remember specifically, and I don't have a permanent picture of the cracks on the bottom, so I can't say for sure, but I know the crack on the top was a vertical crack because it went into the furcation in both sides of the tooth were eventually extracted. But the idea of if you have a patient who comes in and you make the diagnosis that they have a structurally compromised tooth, that's at risk of fracture, they have a consistent pain on biting, and then you restore one tooth. But the pain on biting does not resolve. But you know that you have dissect the crack because you've taken photographs. Then that's the time to happen. And it's only happened a couple of times in my, in my career. But at that time, you flip the mirror over and you look at the top tooth. Make the same risk diagnosis on the isthmus with the cusp thickness, box depth. And then, look at that tooth as a possible source of this pain. Instead of thinking, oh, I probably have a debond, I probably have a gap. Something went wrong with my immediate dentin sealing procedure on this lower onlay I would say if there is a diagnosis of structural compromise in the top two, that would be the time to find out if there is a small crack now there that is contributing to that pain that led to the original treatment of the bottom tooth. And like I say, twice in my career, that's exactly what happened. They did that. So I haven't lost any teeth from that. I only lost my own by self-diagnosis self treatment. And they say that's a pretty and smart way to to look at dental. Diagnosis and treatment. But that's a true story. As the one I'm going to leave with you today. And, so look for referred pain on the arch and also from lower to, to upper arch. You can have a referred pain in that situation. Also. Anyway, till next time, get bonded, stay bonded.