Clinical Tips, Cracks in Teeth, Endodontic Radiography

Now you see it, now you don’t

Sometimes in endodontics, we miss signs, symptoms or findings that are important to diagnosis or prognosis. Sometimes our brain fools us into thinking we see or find things that aren’t really present. This case is a good example of both of these possible errors. The patient presented complaining of mild tenderness to bite on the 26. The tooth was slightly tender to percussion, mobility was normal and there was slight tenderness to palpation on the palatal aspect. Periodontal probing was within normal limits. Here are the intra-oral radiographs:

Bitewing cracked tooth

PA - Cracked toothCracked tooth PA

I decided to take a CBVT scan. The main finding on the scan was a lucency at the mesiopalatal aspect of the marginal tissues.

CBVT_Crack1

CBVT_Crack3

CBVT_Crack2

My plan was now to raise a flap to investigate. Once LA had been applied I probed again. This time I found a narrow deep pocket at the mesiopalatal aspect of the tooth. The locating of a pocket after giving LA that had not been found prior to LA is something that happens in my practice on an occasional, but recurring basis. In fact, it’s been happening since one of my demonstrators made me look silly during my endo specialty program by finding a pocket that I said was never there. I think there are a couple of factors behind this:

1. We are happy to probe more firmly when the patient is numb;

2. Radiographic findings, especially on CBVT point you to a specific location to probe for a pocket.

In a case such as this, the symptoms, followed by the radiographic finding increases the probability of a fracture being present. The added finding of a deep, narrow pocket increases the probability even more. That said, the fracture is not confirmed until visualised. So, a flap was raised and the root surface stained with methylene blue. The visualised crack confirmed the diagnosis.

page7

The CBVT helped immensely in this case. However, it’s easy to look at the CBVT and think, “Ah, I see the crack!” (go back to the bottom CBVT image above and look again),  but also have a look around the rest of the teeth shown in the CBVT. Almost all of them seem to have lucent lines running through them that look like”cracks”. It is very dangerous to look at the lucent line on a CBVT and “diagnose” a crack. All we have in this case from the CBVT is a finding that may be typical of a pattern of bone loss associated with a crack. It added to the other findings to lead to the final confirmation of the diagnosis of cracked tooth via visual inspection.

Let me know your thoughts on this in the comments section below.

Pat Caldwell

Clinical Tips, Diagnosis of Pulpal Pathology, Endodontic Radiography

Perio-Endo? Get Some GP in it!

The second most common reason for extraction of root filled teeth is periodontal disease. So it’s important we identify periodontal disease when deciding if we should treat a tooth. Periodontal pockets around teeth can generally be due to three things:

1. Periodontal disease;

2. Vertical root fracture;

3. A sinus tract draining through the PDL.

Usually, a true periodontal pocket will be broad, whereas a pocket due to a root fracture or a draining sinus will be very narrow. We are more likely to find a true periodontal pocket in a patient who suffers periodontal disease in other teeth besides the one we are looking at.

When we do identify a periodontal pocket in a tooth that also has apical periodontitis, we want to know if the periodontal disease is separate to the apical disease. When these two are combined in a perio/endo lesion, the success rate in treating the teeth is lower than when we have separate perio and endo disease. If the pocket is narrow, then it’s important to differentiate between the draining sinus (which may be easy to treat) and the root fracture, which cannot be treated. I usually do this by raising a flap and inspecting the root with the microscope after staining with methylene blue.

Endo Perio lesion

GP placed into a sinus tract helps determine the true depth of the sinus tract.

In cases where I find a very deep, broad periodontal pocket which I think may be to the apex of the tooth, I place a GP point in the pocket to full length and take a radiograph. If the GP extends to the apex, then I know we have a fight on our hands to save the tooth.

The Endospot

A true perio/endo lesion makes this tooth a difficult prospect for successful treatment.

In the comments section, please leave your tips on identifying perio/endo lesions.

Diagnosis of Pulpal Pathology, Endodontic Radiography, General Updates

Simple Guide to Pulpal and Periapical Diagnosis Part 1

In this post, we discuss a simple and practical method of classifying pulpal pathology that can be used in practice on a daily basis. For the new and updated Endospot Podcast, go to the Podcast Page.

Endodontic diagnosis

How do you classify the pulp in this tooth?

Listen to the episode here (12 minutes):The Endospot Episode 2 | Simple Guide to Pulpal and Periapical Diagnosis Part 1

References Referred to in This Episode:

BARBAKOW F, CLEATON-JONES P, FRIEDMAN D. Endodontic treatment of teeth with periapical radiolucent areas in a general practice. Oral Surg Oral Med Oral Pathol 1981. 51, 552–559.

BENDER IB. 2000 Pulpal Pain Diagnosis. A Review. J Endod 2000. 26, 175-179

BENDER IB. 2000. Reversible and irreversible painful pulpitides: diagnosis and treatment. Aust Endod J 2000. 26, 10–14.

MILES TS. Dental pain: self-observations by a neurophysiologist. j Endod 1993. 19, 613-5.

SELTZER S, BENDER IB, ZIONTZ M. The dynamics of pulp inflammation: correlations between diagnostic data and actual histologic findings in the pulp. Oral Surg Oral Med Oral Pathol 1963. 16, 846-71 and 1963. 16, 969-77.

SIGURDSSON A. 2003. Pulpal Diagnosis. Endodontic Topics. 5, 12-25.

Transcript:

Welcome to the Endospot Episode 2.

My Name’s Pat Caldwell and today we’re coming to you from Shanghai, China. On our website we have the complete list of references discussed in this episode, so go to www.endospot.com and remember you can sign up online to receive the Endospot directly to your inbox.

In this episode, we’ll be discussing the classification of pulpal pathology. This will be the first in a series of three episodes looking at the issue of diagnosing pulpal and periapical pathology and in this episode we’ll go through a useful classification system which will help you deliver appropriate treatment to your patients. I’ve broken it up into three episodes because diagnosing and therefore treating appropriately is just so important. I think that often not enough time and thought goes into the initial diagnosis and that is when errors are made and our patients suffer. As endodontists we often see cases where an incorrect diagnosis has been made and treatment either withheld or provided when it wasn’t required and as professionals we owe our patient more than that.

When we look at the pulp and periapical classification systems, there are many out there, but in my opinion the simplest and most useful is the one proposed by Asgir Sigurdsson (Sigurdsson 2003). He published an excellent journal review article on this particular topic in everyone’s favourite journal, Endodontic Topics and that’s the classification system I’ll be discussing today. This classification is very much designed to give a clear indication of the treatment requirement according to the diagnosis, and when it comes down to it, that’s what we’re really looking to achieve out of our diagnosis.

Now when I’m faced with a new patient, whether they are presenting in pain or not, I will still conduct a complete history and examination and make both a pulpal and periapical diagnosis. I split the diagnosis into pulpal and periapical because it helps me have clear in my mind exactly what I’m dealing with, how we should proceed and what follow up’s required. It will also give us clues as to what problems we might run into, such as if the tooth will be difficult to anaesthetise, or if there’s likely to be a high level of post-operative pain. To be fair it will most often be the pulpal diagnosis that is driving your treatment decisions and that’s another reason to spend an episode on going through the various diagnoses.

Now if you think about it, the only way we can definitively diagnose the state of a pulp is to extract the tooth and slice it up and look at it through a microscope. So, our clinical diagnosis is always going to include an element of a guess and I can assure you that it will not always be straightforward. But I dIgress, we’ll get onto how to diagnose in a future episode so now let’s get back to the topic at hand. The classification system we are going to be using includes 4 different diagnoses for the dental pulp, and one of them is the healthy pulp. That’s the easiest one so we will start with that one.

A diagnosis of healthy pulp assumes that the pulp is vital and is not inflamed in any way. This tooth will respond normally to pulp testing, that is hot, cold and electric.  It will be asymptomatic and shouldn’t be tender to percussion or palpation unless there is an occlusion issue causing this. We use this classification sometimes when we need to do RCT on a tooth for prosthodontic reasons. So an example might be where there is not a lot of coronal tooth structure remaining in a vital tooth and the restorative dentist feels that an intracoronal restoration is required in order to provide retention for a core.

We’ll now move on to the more complex diagnoses, the ones indicating some sort of inflammatory response. The first of these is Reversible pulpitis. If we looked at this pulp under a microscope, we’d see a vital pulp with areas of localised inflammation. Most commonly this will be associated with a response to caries or possibly microbial leakage of a restoration. It could also be due to exposed dentine or bacterial ingress along a crack. All these things will lead to inflammation in the pulp. Now by definition, this inflamed pulp should heal when we remove the cause of the inflammation, so it’s important not to misdiagnose this pulp with an irreversible pulpitis and initiate RCT when it’s not needed.

A pulp with reversible pulpitis can present with quite a broad range of symptoms. Typically, the patient will describe pain with hot or cold, or with biting in the case of a crack. The pain might be mild, but can sometimes be severe, but probably the key to this diagnosis is that removal of the stimulus will lead to rapid relief of the pain. For example, drink something hot, tooth hurts, swallow the drink, tooth is fine. In general, there should also be no report of spontaneous  pain, and no tenderness to percussion or palpation. The tooth is likely to respond to a pulp test, but the inflammation in the pulp might mean that an exaggerated response is gained.  This in itself isn’t an indication of irreversible pulpitis, if the other indicators are that of reversible inflammation.

When you diagnoses reversible pulpitis and remove the stimulus by removing caries, or covering exposed dentine, it’s important that you review the patient and re-do all the examination procedures. Because if you think about, if you’ve diagnosed reversible pulpitis, say in case where there is a carious lesion and you treat it by removing the caries and placing a restoration, but the symptoms remain then by definition the pulp wasn’t reversibly inflamed.

Choosing between a diagnosis of reversible pulpitis, and it’s for more unpleasant alternative irreversible pulpitis is a critical decision, because the treatment options are very different. Where a pulp is irreversibly inflamed, this means that the inflammation is so severe that the pulp will not be able to heal. It will eventually necrose and become infected, leading to apical periodontitis. The treatment for these teeth is to undertake root canal therapy in order to remove the diseased pulp tissue and prevent infection.

As with reversible pulpitis we see a wide range of presentations. Commonly there is an exaggerated response to hot and cold, but the key here is that this response lingers for some time. It’s hard to say exactly how long it has to linger to be considered irreversible, so here I’ll have to take some licence and say that a pain that lingers for a number of minutes after stimulus is not a healthy pulp. There is a good biological explanation for this lingering pain but I’ll go through that with you in the diagnosis episode. Sigurdsson tells us to be careful when interpreting this symptom as if you put an intense stimulus even on a healthy pulp the resulting pain will linger somewhat.

Another indicator that we’re dealing with an irreversibly inflamed pulp is where the pain has been severe, and the longer it has been present, the more likely it is to be irreversible in nature (Bender 2000). When pulp testing this tooth, there will often be an exaggerated response and the dull lingering pain experienced before will be induced by the procedure. Tenderness to percussion is often also present. The level of inflammation in these teeth will often lead to neurogenic pain and nerve sprouting which results in inflammation in the periapical tissues. This can occur well before the pulp starts to die and therefore even in a vital, inflamed pulp, tenderness to percussion is often present.

Probably the biggest indicator of an irreversibly inflamed pulp is spontaneous pain. So the patient will report moderate to severe pain that suddenly occurs, and often remains as a dull lingering pain for minutes or hours. They might even report being woken by the pain. I often find that patients with irreversible pulpitis have resorted to over the counter painkillers such as ibuprofen and report that these drugs will help relieve the pain until they wear off of course.
There is an excellent article published by Timothy Miles, who is a neurophysiologist who had previously trained as a dentist (Miles 1993). In the article he explains in detail his not only the physiological response he personally experienced due to a dying pulp, but also the emotional response. It has a grand total of 6 references which it probably could have done without and yet was published in the Journal of Endodontics. It’s probably essential reading for any dentist who has never experienced toothache, and I’ll put the reference in the show notes. If you ever sit the examinations for the Royal Australasian College of Dental Surgeons, then I believe he still lectures on the primary orientation course, and you can have the pleasure of hearing the story in person.

Our final diagnosis is pulpal necrosis. This covers both partial and complete necrosis of the pulp. Consider the progression from reversible pulpitis to irreversible pulpitis and on to pulpal necrosis. At some point the inflammation builds to a level where the vital tissue dies. This necrosis over time then spreads throughout the whole pulp space. There isn’t a lot of information on exactly how quickly the process occurs and I imagine that there is a great variation in the length of that process, but when it comes down to it, some form of Root canal therapy is required.

Most of the time when a pulp is necrotic, it will also be infected. There are a few situations where a pulp can necrose and remain uninfected, mostly after physical trauma to a tooth, but on the whole, a dead pulp lacks a blood supply and therefore lacks the ability to protect itself against microorganisms. These bugs will get into the pulp space through cracks or infected dentine, or possible exposed dentinal tubules and rapidly take over the necrotic space.

When dealing with a patient presenting in pain, there is a strong correlation between the following factors and pulpal necrosis. First is a history of moderate to severe pain. Second is tenderness to percussion, third is a history of spontaneous pain and fourth is a negative pulp test. Seltzer and Bender conducted some of the most useful research we have on this topic way back in 1963 (Seltzer et al. 1963). Basically, they examined patients who presented with pain and then the tooth was extracted and examined histologically. There is a nice summary of their findings in a paper published by IB Bender in 2000 in the JOE which you should read if you are a postgraduate student (Bender 2000).

It’s important to note here though that very often the progression from vital to necrotic pulp is painless, or the level of pain is minimal and no help is sought for the problem. Often patients are completely unaware that they have a chronic infection in their jaw. Two studies reported this happening in 26-60% of cases. (BARBAKOW ET AL. 1981, BENDER 200) In my experience these teeth may be completely asymptomatic. They can be slightly tender to percussion but often don’t even present with this. Usually, they are identified due to a lucency on a PA or OPG Xray. The key for these though is that they will not respond to a pulp test and can be entered without local anaesthetic.

OK, I think that’s enough for this episode. Next episode we’ll be discussing the various periapical diagnoses that we can make. In the meantime, I recommend you have a look at the references, and next time and every time you work on a tooth, have a think about what diagnosis you have for the pulp. If you’re placing large restoration or crown think about whether you’re completely confident of your diagnosis before doing the work.

Also, if you’ve got a comment, or you disagree with something that was said here, please keep it nice, but I’d love you to go to the blog and leave a comment.

Clinical Tips, Endodontic Radiography

How to Improve Your Endodontics in 30 Seconds Flat

Endodontic radiography

Same Tooth, Very Different Images. Taking an Additional Radiograph Provides A Whole Lot More Information

A simple way to improve your endodontics is to simply take two radiographs where you might previously take one. I routinely take two radiographs with differing horizontal angulations when treating potentially multi-rooted teeth (basically everything apart from maxillary incisors) unless there is a reason not to. When dealing with root canal anatomy we’re dealing with a very three dimensional issue, yet a lot of what we plan and assess our treatment on is two dimensionally based. There are so many reasons to take additional views, and in the long run it can make your life easier and improve your endodontics.

The process of taking an additional radiograph adds 30 seconds or less to the radiograph time. You already have the rubber dam folded back and the x-ray tube in place. Developing two radiographs instead of one does not take any longer (especially with digital). More importantly though, you simply have far more information to work with. Additional canals that might not be visible on a standard radiograph will often be visible on a mesial tube shifted radiograph. Where roots that lie close together have differing lengths, this may not be obvious with a radiograph that superimposes the two roots.  Similarly, two radiographs will allow you to determine more accurately which root a lesion is associated with.

Taking an additional radiograph when measuring working lengths is essential, as often files will superimpose on a radiograph and thus, the information on where the file ends relative to the root tip can be lost. This applies for obturation radiographs also.

The image on the right appears to show one distal canal, but the mesial tube shift reveals two separate canals.

The image on the right appears to show one distal canal, but the mesial tube shift reveals two separate canals.

Let’s not also forget that occasionally, we may take a radiograph that is not of diagnostic value. For example when the apex of the tooth in question has been missed on the radiograph. The second radiograph may have sufficient information to save you having to re-take the radiographs.

The negative aspect of additional radiographs is the increased radiation exposure for the patient. Obviously, it is important to weigh up the benefits versus risks of taking the additional radiograph, and in my opinion, the potential to improve the endodontic outcome makes the taking of these radiographs imperative.

I was recently sent an x-ray by a referrer who had root filled a vital upper pre-molar, however the patient complained of ongoing discomfort associated with the tooth. The radiograph showed a well condensed root filling that appeared slightly off centre from the middle of the canal. I advised taking a mesial shift of the tooth and the presence of a second canal was obvious. After treatment of the missed palatal canal, the tooth was asymptomatic and ready for restoration. It would have saved quite some trouble, as well as time had the mesial tube shift radiograph been taken prior to, and during treatment.

Untreated Canal

This tooth remained symptomatic after treatment. Note the obturated canal appears slightly off-centre.

Untreated Palatal Canal

A radiograph taken with a mesial tube shift clearly shows a palatal canal which has not been prepared or filled.

Resolution of symptoms

Upon cleaning and shaping of the palatal canal, the symptoms resolved.

I’d love to hear reader’s thoughts on this topic, or case examples where tube shift radiographs have assisted to improve the quality of endodontic treatment. Please leave a comment with your thoughts.