Author Archives: Ellen Park, DDS, Cert(Endo), MSc, FRCD(C)

it’s vital…with no fillings…but it hurts!

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Radiographs can be so deceiving! This radiograph of the first quadrant looks so calm, so unassuming…everything looks normal. What you didn’t see was the patient attached to this radiograph – having extreme, radiating pain. When everything looks fine on the radiograph, and we have a quadrant full of unrestored or minimally restored teeth, my spidey sense tells me to pick up a probe, and also a transilluminating device. In this particular case, there were no isolated deep probing depths (often suspicious of a root fracture), but transillumination revealed a cracked tooth. The pain can likely be ascribed to the process of “fracture necrosis” – eventual necrosis caused by a significant crack from the outside of the tooth to the pulp. A crack is just one of five types of fractures, which also include craze lines, cuspal fractures, root fractures, and a split tooth. Each are managed a little differently, depending on the presentation.

In this case, we performed a pulpectomy, and used the microscope to look into the crown. It did not appear that the mesial-distal crack extended past the CEJ. The patient had a temporary crown placed that week – and the tooth became comfortable over the ensuing weeks. This is often a nice way for us to ensure the tooth will be comfortable under a crown – an orthodontic band often serves the same purpose. The endodontic therapy was then completed. Even despite the good restorative work that was eventually completed, a tooth with a crack always has a long term guarded prognosis.

Teeth with cracks and fractures can be difficult to detect, visualize, diagnose, and treat. The prognosis of teeth with cracks and fractures also comes with uncertainty and risk. Furthermore, the symptoms of teeth presents with cracks and fractures run the gamut from mild biting sensitivity to severe and radiating pain. However, a few visual aids, like a transillumination light, magnification, and the trusty old periodontal probe can help us to diagnose and manage such cases.


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MTA…saving open apices one tooth at a time!

Providing root canal treatment can be challenging in teeth with incomplete root formation. The apex is large and open, the canals walls are thin and fragile, and this makes disinfection and obturation hard to do. Before the advent of MTA, calcium hydroxide was used in teeth with open apices over a long period of time, anywhere from 6 months to 24 months, to induce a calcified barrier over the open root apex. It was and still is a very effective treatment modality, especially with a good coronal seal. Calcium hydroxide is also still very important for treating resorptions, and aiding in disinfection of root canals! However, we now know that keeping calcium hydroxide for many months in a weak root can possibly further weaken dentin, and using MTA can shorten the treatment time to one or two visits. The placement of a “plug”, usually a 3-5 mm plug of MTA at the end of an open apex root canal, provides an “instant” apical barrier against which we can place gutta percha and sealer into the remainder of the root canal.

In this particular case, the patient was going to have new crowns placed very soon. I removed the old gutta percha quite easily with a #35 Hedstroem file, and you can see all sorts of things growing on it in the photo! Because the tooth was purulent and “weepy”, the root was allowed to drain for a few minutes, and then irrigated with 5.25% sodium hypohlorite using a closed-end side-vented irrigation needle after the working length was determined. I packed calcium hydroxide into the root for about 2 weeks in this tooth before doing the one-visit MTA apexification procedure due to the continued exudate and to aid in disinfection.

On the day of MTA apexification, this is what I did:

1. Rubber dam of course, irrigate calcium hydroxide out with full strength sodium hypochlorite, circumferential filing, and final irrigation procedures

2. Dry the canal. At this point, if the canal continued to well up with exudate, I would consider remedicating with calcium hydroxide.

3. Place an apical matrix of collagen (for example, Collacote) if you feel you might need an apical matrix to “contain” your MTA plug; this serves as a support against which you can gently condense the MTA.

4. Using a small carrier, such as a Dovgan carrier or MAP system (like a mini amalgam carrier), place MTA as far apically as possible, and then carry/tamp down gently using a pre-measured plugger or a moist paper point (a big one, like extra coarse!).

5. I usually take a radiograph here after the first 1 mm increment, to make sure that I have placed it flush with the root apex. Once this is confirmed, you can place a 3-5 mm plug.

6. The rest of the canal can be obturated with sealer and thermoplasticised GP, and the tooth definitely restored. Many also advocate placing a damp cotton pellet and temporary filling before definitively restoring the access to ensure the MTA has set. In the x-ray, I have placed 5 mm of MTA, sealer and GP on top, a 2 mm layer of glass inonomer, and then a bonded restoration (double seal). The dentist has completed the case with beautiful crowns.

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How can an apicoectomy help?

Let’s not give up on even the smallest of teeth!

There are times when conventional root canal treatment or retreatment cannot heal every periapical lesion out there. Luckily, we have the option of an apicoectomy – which in today’s terms, means microsurgery. During an apicoectomy, the most apical part of the root tip (usually about 3 mm) is removed. A retropreparation – which is similar to a class one preparation – is made using an ultrasonic tip specially designed and angled for apicoectomy under the microscope. The retropreparation is filled with an MTA material, of which there are many choices now, like the traditional powder that is mixed with sterile water, or even a pre-mixed putty.

In this case, we see a tiny little lateral incisor, which has a ceramic crown that is a few years old, and underneath it, a great big post. The current root canal treatment is somewhat underprepared, and was done more than 15 years ago. The tooth had recently become symptomatic. Is it extraction time for this little tooth? Should we dismantle the crown, remove the post, and retreat it? Should we place an implant now?

This case was ideal for an apicoectomy. This means the patient is able to keep the crown intact and we wouldn’t be compromising restorability by removing the post. With such a short and fine root, we have to be aware of the crown to root ratio, occlusion, and be conservative in our surgical technique.

After a full thickness flap was created, the retropreparation and the MTA retrofilling are seen:

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Here are the radiographs from start to finish: initial presentation, immediately after the procedure, and 6 months after with good healing.


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Irrigation…how low do you dare to go?

Irrigating the canals…probably the easiest part of providing root canal treatment, yes?

I think I graduated from dental school years and years ago with a deeply instilled fear of perforation, a reluctance to tackle calcified teeth, and anxiety whenever I waited for my obturation film to emerge from the processor. Irrigating the root canal was the breeziest part of treatment, to my memory. I placed an irrigating tip into the canal, made sure it didn’t bind in any place, it was probably hanging around the coronal or mid-root part of the canal, and I pressed the plunger a few times. Presto! Irrigation done. Right. Right?

Reading up on the irrigation literature these past few years has changed my thinking about the importance of irrigation, and it is a procedure that I spend a lot of time on now, probably equalling instrumentation! Many advocate viewing shaping of the canal with rotary instruments as a means to allow irrigants to effectively reach the most apical portion of the root canal. Many would be surprised to see that if our irrigation needle tips are not placed in the apical third of the root canal, we may not be achieving effective irrigation. The easiest way to show this is through a little home made video here, which shows me irrigating in a plastic canal, with a 30 gauge needle, using a fair amount of pressure, equal to about 5 ml/min. The needle tip is held about 3 or 4 millimeters from the “end” of the root canal. Notice how the exchange of irrigant only extends a small distance beyond the end of the needle tip: 

Based on some of the literature to date, here are a few suggestions for achieving effective irrigation using a conventional irrigation method:

1. Use a flexible, small gauge irrigation needle, for example, a 30 gauge needle or smaller, that is designed with a closed-end and side-vent (for patient safety). I find that it is quite difficult to use an irrigation needle bigger than a 30 gauge needle, unless the root canal is very large.

2. Prepare the root canal to an adequate apical size and taper such that a small gauge irrigation needle can be placed within 1-2 mm of the working length, or at least in the apical third.

3. Use very gentle finger pressure! A high irrigation flow rate (e.g. high finger pressure) is not required; recent research shows that high pressure/high flow rates does not correlate to “better cleaning”.

4. Activate your irrigants! Use of a sonic or passive ultrasonic tool, such as the EndoActivator by Tulsa, or the Irrisafe file by Clinical Research Dental can make your irrigation more effective. There are many options for agitating your irrigants, and I try to “energize” each irrigant that I use for at least 45-60 seconds per canal, per irrigant, after the majority of the cleaning and shaping has been done.

If you like reading journal articles, here is my recent paper on the “theoretical measured pressure” that the periodontal ligament might feel when we are irrigating root canals. We also have a review paper on irrigation of the apical third in the journal Endodontic Topics, have a read. Send us a message if you can’t find it. Park Shen Haapasalo 2013 irrigation JOE


How do you “seal” the deal?

After we’ve spent so much time doing great endodontic treatment – with rubber dam isolation, perhaps gingerly applying OraSeal or Kool-Dam to make sure everything is water tight, carefully instrumenting, copiously irrigating, and then obturating with great style – how can we protect our painstaking work?

Here is a case where the root canal has been completed, but unfortunately, the final restoration – a ceramic restoration – has been made without replacing the cotton pellet and temporary base material. Even though the periapical lesion has healed nicely, the risk of coronal leakage, and thus the need for retreatment in the future again, is great.

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One nice way to prevent coronal microleakage is to definitively restore the teeth after root canal treatment. If you want to go one step further, you might consider an intra-orifice barrier. This is simply a (bonded) restoration that involves removing approximately 2 mm of gutta percha from the orifice of the root canal. Then, a material, such as glass ionomer, or composite, or MTA can be placed into the orifice. I also prefer to cover the furcation floor. I have been placing an intra-orifice barrier of glass ionomer (and often a 1 mm intra-canal barrier when I prepare post spaces), and then restoring the rest of the access with a bonded core material when indicated. The glass ionomer can be placed with a small plugger, or a Centrix Accudose needle tube.

I have also been trying a neat product as an intra-orifice barrier, PermaFlo Purple, which is simply a flowable composite that is colored purple. You can place a tooth-colored material on top, in the bulk of the access. I suppose the rationale of a purple-tinted flowable composite is to make any future treatment easier, since you’ll be looking for purple composite, instead of B2 composite! The case below shows a 2 mm intraorifice barrier of glass ionomer, extending below the floor of the root canal chamber.

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I’m having a flare-up!

When our patients experience a “flare-up”, we wish they were experiencing a transcendental jazz trumpet experience, and not the other kind, the endodontic kind!

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Fortunately, the reported incidence of flare-ups is relatively low, generally somewhere between 1-8%.  But when it happens, no one is happy, which is a negative experience for the patient, of course, but is hard on the clinician too, especially when we secretly congratulated ourselves only 12 hours earlier for getting through that tough and calcified access or for creating one of the most beautiful obturation radiographs known to man. It can happen to any of us, and we cannot predict who, exactly, will experience a flare-up.

Definition:  moderate to severe pain hours or days after initiation or completion of endodontic treatment, with or without swelling.

Etiology & Diagnosis:  the main culprit is usually microbes, but can be due to mechanical or chemical reasons too.  Over-instrumentation, incomplete instrumentation, apical extrusion of infected debris, and the irrigants or sealers used can all contribute to the occurrence of a flare-up.  The diagnosis of a flare-up is often simple, but is important to rule out pain from adjacent teeth and pain of non-endodontic origin.  The local considerations for the tooth itself might include a crown or root fracture or an untreated canal (particularly if there is temperature sensitivity).  We also need to identify any signs of spreading infection, osteomyelitis, fever, swelling, etc., and treat that appropriately, with the appropriate antibiotics and very careful follow-up, or referral to an oral surgeon if there is potential for danger, which can develop extremely quickly.

Management:

1. Reassure your patient: patient does appreciate when we explain what is happening and why, and the steps we are going to take, including following up.

2. Definitive treatment:

  • opening the tooth up under a rubber dam again, to provide re-instrumentation to a proper working length with copious irrigation.  This also gives us a chance to search for any untreated canals, and allow for any suppurative drainage.  If there is drainage, allow the tooth to drain, which can take several minutes.  Avoid leaving the tooth “open” – that is, without a temporary filling in the access- and always place an intra-canal medicament, such as calcium hydroxide.  Occlusion can be reduced.
  • incise and drain (I&D) if there is vestibular swelling.  If the abscess is localized, generally antibiotics are not needed unless there are other signs of systemic infection, cellulitis, poor drainage, or immune compromise.
  • cortical trephination – the jury is out on this one.  While this is not indicated routinely, it should be considered in areas with dense and thick cortical plates (i.e. lower molars).

Drugs: NSAIDS such as ibuprofen address inflammation very well, but some patients may require stronger analgesics, or combinations of analgesics for adequate pain relief.  My “go-to” is generally ibuprofen, and I rarely find that I need to prescribe narcotic analgesics.  However, I will consider acetaminophen only (plus or minus an opioid), other NSAIDS, or combinations of analgesics, depending on the patient’s risk of GI bleeding.  Antibiotics will not reduce post-treatment pain or decrease the risk of developing a flare-up when used prophylactically, but are indicated when there is sign of systemic involvement, presenting as fever, malaise, cellulitis, lymph node involvement, trismus, rapid onset of severe infection, or a compromised immune system.

Prevention: it is important to inform your patients that they may experience a flare-up!  Tell them what to expect, how to identify the symptoms, and how they may reach you if this should happen.  I discuss this possibility with every patient.  If your patient comes to you with significant pain before you even start treatment, now is the time to consider pre-operative dosing of analgesics, and possibly a single oral dose (some prefer supra-periosteal infiltration) of an appropriate steroid (a common dose is 4 mg of dexamethasone) if there is no know contraindications.  Finally, shaping techniques such as a “crown-down” method may help prevent us from pushing infected debris into the periapical area.