Diagnosis of Pulpal Pathology, Endodontic Radiography, General Updates

Simple Guide to Pulpal and Periapical Diagnosis Part 1

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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 LA, General Updates

The Endospot Episode 1 | Preventing Local Anesthetic Failure in Endodontics

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Problems with Local Anaesthesia?

In this, post, we discuss practical techniques for preventing failure of LA for endodontics, especially when dealing with irreversible pulpitis. Listren to the audio file below:

Preventing Local Anesthetic Failure in Endodontics

For the new and updated podcast, go to the podcast page.

References referred to in this podcast:

Meta Analyisis on Artciaine V lidocaine:
KATYAL V. 2010. The efficacy and safety of articaine versus lignocaine in dental treatments: A meta-analysis.  J dent: 38: 307-317

Intraossesous Injections:
READER A, NUSSTEIN J. 2002. Local anesthesia for endodontic pain. Endodontic Topics: 3: 14–30

Use of Articaine for buccal infiltration:
MATTHEWS R, DRUM M, READER A, NUSSTEIN J, BECK M. 2009. Articaine for Supplemental Buccal Mandibular Infiltration Anesthesia in Patients with Irreversible Pulpitis When the Inferior Alveolar Nerve Block Fails. J Endod: 35(3): 343-346
AGGARWAL V, JAIN A, KABI D. 2009. Anesthetic Efficacy of Supplemental Buccal and Lingual Infiltrations of Articaine and Lidocaine after an Inferior Alveolar Nerve Block in Patients with Irreversible Pulpitis. J Endod: 35(7). 925-929

PSA Block Link –
Information on the PSA Nerve: http://en.wikipedia.org/wiki/Posterior_superior_alveolar_nerve
Video: You Tube Video on the PSA Nerve Block

Show Transcript:
Welcome to the Endospot Episode 1.
In today’s podcast I’ll be discussing my techniques for managing local anaesthetic failure and specifically how to manage teeth diagnosed with irreversible pulpitis.

On the site we have references and show notes for this episode, so head to www.endospot.com and remember you can sign up and receive the Endospot blog posts directly into your inbox.

So let’s get on with the podcast.

On the topic of failed LA, it’s important to recognise situations where complete anaesthesia is likely to be difficult to obtain. In general terms, the mandibular molar teeth are the most difficult to anaesthetise, and this is where you’re likely suffer the most failures.
The issue with mandibular molar teeth is compounded where we have an irreversible pulpitis. The inflamed pulp is always going to more difficult to anaesthetise. You’ll often have a slightly distressed patient in this situation, so it’s important to get it as right the first time. Once you’ve begun treatment on an anxious patient and they’ve suffered a level of pain due to failed LA, it can be quite difficult to win back their faith in you.

Now it’s certainly my experience that where the pulpitis has been long standing and is becoming more and more acute, this will be the most difficult tooth to get numb. A good example might be a case of cracked tooth syndrome where the tooth has been manageably painful to bite for months, but is now becoming more and more sensitive to thermal stimuli and spontaneous pain has begun to occur. I suggest you hit these ones with every trick in the book.

Abscessed teeth don’t normally represent a huge problem for anaesthesia in terms of being able to instrument the canals, but sometimes the surrounding tissues will be difficult to anesthetise and the patient will still respond to things like pressure. One caveat here though. Just because you’ve made a diagnosis of abscess, don’t assume that there is no vital tissue in the canal. Some vital tissue can remain in the canal even in the presence of pus and swelling, and attempting to debride this canal can result in high levels of pain. So, I always assume the worst when dealing with patients in pain and provide complete anaesthesia

In my previous last post, I covered the reasons for LA failure in pulpitis cases, so if you want more details and references, go to the blog post at endospot.com and review those there. The main points that are worth considering though, are that a numb lip after IANB does not necessarily equal pulpal anaesthesia. This is the case even when dealing with an uninflamed pulp, but is especially so where you are dealing with an inflamed pulp. Research generally tells us that if we are dealing with an irreversible pulpitis and we give an IAN block which is apparently successful as the patient’s lip is numb, then , we’ll still only be successful in completely anaesthetising the tooth nerve about 55% of the time. Now, that’s obviously unacceptable, so we’re going to need to use supplementary LA for these cases.

The second point to note is that LA takes time to work. Again, research tells us that in 19-27% of cases, complete anaesthesia doesn’t occur until 15 minutes after the injection. So, next time your LA fails, it may simply be that the LA hasn’t had time to work. Supplemental techniques such as the PDL and intraosseous injection tend to work much faster than IADB, and should have you removing that inflamed pulp much faster.

As to which type of LA you should use, this will to a certain extent come down to personal preference, and obviously the medical profile of the patient. In general terms though, I would recommend using articaine. There’s been plenty of research in recent years devoted to articaine with some conflicting results. But, a recent meta-analysis concluded that articaine was more effective than lidocaine for anaesthetising mandibular molars. The article is by an Australian and so refers to lignocaine, but I assure you it’s the same drug.
So now I’ll go through my standard technique for dealing with hot pulps. Wherever not contraindicated, I’ll prescribe ibuprofen as soon as possible prior to treatment. There is some evidence that this alone may assist in achieving complete anaesthesia in inflamed pulps, but even if it doesn’t let’s remember that  these patients are presenting with pain, and therefore are at risk for post-operative pain. In this case, Ibuprofen (unless contraindicated) would be part of my pain management regime anyway.

When faced with a hot mandibular molar, I’ll start with a regular IAN Block and follow this with a buccal and lingual infiltration. The buccal infiltration ensures that a rubber dam clamp can be placed comfortably, but more importantly, I think that combining the block of the nerve with the local infiltration simply means that we have two sites along the nerve trunk that are blocked and this will lead to improved anaesthesia. This makes a lot of sense to me and is backed up by a number of studies which show that in cases of irreversible pulpitis, the infiltration significantly improves success rates. These studies have also shown the improved effect of articaine over lidocaine for this purpose.

After the buccal and lingual infiltrations, we take a minute’s break to ensure they are active and then move onto the PDL injection. There are a number of specialised equipment kits for PDL injections available, but they can be done successfully with a standard syringe. The first step is to bend the needle with some haemostats so that you are able to place pressure on the needle as it is forced into the PDL. The needle is inserted into the gingival crevice and with the bevel facing away from the root surface. Press hard and inject for 10s. There should be back pressure, if there isn’t, then the solutions wont’ be forced through the cribriform plate into the cancellous space and won’t be effective. I’ll perform the PDL injection at the four corners of the tooth.

The PDL injection is not really a PDL injection. I mentioned that the solution is forced into the cancellous space and as such It’s really an intraosseous injection. Therefore, there may be cardiovascular effects and this should be taken into account when selecting the LA. If an adrenaline containing LA is contraindicated, then you can use a non-adrenaline containing LA for this purpose.

The rate of onset of a PDL injection is fast, but the duration is short compared to IAN block, so at this point I’ll get a rubber dam on to the tooth and start access almost immediately. Once the pulp space is penetrated, and if vital tissue is found, then I’ll perform an intrapulpal injection. This injection relies on backpressure, so can only be used if only a small perforation is made into the pulp chamber.
For maxillary molars, I’ll start with a buccal and palatal infiltration, injecting most of the cartridge bucally. The palatal injection allows the rubber dam clamp to be placed comfortably, but might also anaesthetise the palatal root where a buccal infiltration could fail. After this, I perform a posterior superior alveolar block. I’ve placed a link in the show notes so you can have a look at this technique if you’re not familiar with it. I think that in the same way that the buccal infiltration in the mandible works with the IAN block to improve anaesthesia by blocking two points along the nerve trunk, combining a SPAN block with infiltrations should do the same. I then move onto PDL injections and perform an intrapulpal once the pulp chamber is entered.

The vast majority of cases, these procedures will allow you to enter the pulp space and remove most of the inflamed pulp tissue. If you are unable to even enter the pulp space, then your only real option is to perform an intraosseous injection. This does require specialised equipment. A good review of this technique can be found in the endodontic topics article referred to in the show notes. If you are comfortable with intraosseous injections, then these can be substituted for the PDL injections in the standard routine. My practical experience though is that if you follow the techniques described you really should have a very high level of success.

One point to note though is that infiltrations and PDL injections won’t make up for a failed IANB, so if there is any doubt that the block has been successful, then it’s worth repeating the block. If you want to be certain, it might make sense for you to perform the block and then wait until there are significant signs of lip and tongue anaesthesia before going onto the infiltrations and PDL injections. Obviously these injections can cause lip numbness also and so can mask a failed IAN block.

After entering the pulp chamber, you may find that you can remove some or most of the pulp tissue but attempting to pass a file to length in the canal elicits pain. In this case, I don’t see any reason to persist as the process of removing the bulk of the pulp tissue will result in resolution of the patient’s symptoms. I’ll dress the tooth with a corticosteroid containing dressing such as ledermix or odontopaste and send the patient home with assurances that the symptoms will resolve and the tooth will be easier to treat at the subsequent visit as the inflammation in the pulp will have resolved greatly. If you persist when complete anaesthesia isn’t achieved, you’re likely to put your patient and yourself through a lot of unnecessary pain, and the patient will be sure to be more anxious and will probably be one of those people that for the rest of their life tells their friends how agonising root canal treatment is.

So that is my routine for dealing with hot pulps. I’m aware there will be many different techniques out there and I’d love to hear some feedback. For those listeners who are just beginning their career, I’d recommend getting into the habit of using block and infiltration anaesthesia for all endodontic cases, and adding the PDL and intrapulpal injections when required.

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