Photon Induced Photoacoustic Streaming (PIPS)

January 1, 2012 Pat Caldwell 2 Comments

Happy New Year from the mountains of Japan where I’m hitting the ski slopes, eating some delicious meals and soaking up some fantastic Japanese hospitality. Last night we were served the traditional midnight meal of Soba Noodles by our hosts at the Sidehill Lodge in Hakuba, Nagano Prefecture.

The skiing Budda accross the road from our lodge in Hakuba

I’m a fan of utilizing passive ultrasonic irrigation (PUI) to improve the effectiveness of our irrgants, and believe that it produces root canals with fewer debris and bacteria than needle irrigation alone. Recently there has been some talk about the use of lasers to activate our irrigants in a similar manner and there is at least some evidence that this may improve the cleanliness. Here is a promotional video to give you a brief overview:

httpv://www.youtube.com/watch?v=U0dLJWm6LGk&feature=related

Now, we are still waiting on evidence to prove that any of these methods provide a better outcome in terms of healing or prevention of apical periodontitis, but in the meantime, we should be aiming to produce the cleanest canals we can.

My colleague Mateus Miranda has volounteered to look into the use of lasers to activate irrigants and has produced a nice overview of the available evidence. The key paper so far is probably the one by Ove Peters in the JOE in 2011 showing an improved ability of the technology to reduce, but not remove bacteria from intra-orally infected teeth.

Enter Mateus……….

There has been recently introduced onto the dental market a said “revolutionary” mechanism for cleaning and debriding of root canal systems. The PIPS uses Erbium: Yttrium Aluminium Garnet (Er:YAG) laser energy at sub-ablative power levels which produces wavelengths of 2940nm. PIPS was developed by Dr. Enrico DiVito with assistance from Dr. Mark Colonna.

This non-visible-to-human-eye laser energy is strongly absorbed by water and when activated with specific peak power derived from short pulse duration results in a photomechanical phenomenon or photo-ablation on dentin, allegedly removing smear layer and exposing dentinal tubules.

The Er: YAG laser was tested for the first time in 1988 for preparing dental hard tissues. It was successfully used to prepare holes in enamel and dentine with low ‘fluences’ (energy (mJ)/unit area (cm2)). In 1989, it was demonstrated that the Er: YAG laser produced cavities in enamel and dentine without major adverse side effects (A. HUSEIN 2006).

In 1998 a study performed by TAKEDA FH and colleagues concluded “The root canal walls irradiated by Er:YAG laser were free of debris, with an evaporated smear layer and open dentinal tubules. These results suggested that Er:YAG laser irradiation had an efficient cleaning effect on the prepared root canal walls. FLAVIO SOARES et al (2008) found laser cleanliness in root walls of primary teeth was similar with rotary instruments and superior to manual instrumentation and it required less time for completion. KYOKO INAMOTO et al in 2009 found no smear layer presence following instrumentation of root canal walls using the same laser therapy.

Irrigation wise, ROELAND JG De MOOR et al (2010) showed the efficacy of Laser Activated irrigation (LAI) using Er:YAG for 20 seconds compared to Passive Ultrassonic Irrigation (PUI) for 60 seconds for dentinal debris removal. DIVITO et al (2010) concluded the Er:YAG laser used in this study showed significantly better smear layer removal than traditional syringe irrigation.

Considering thermal effect, studies were performed and were conclusive on the safety of the Er: YAG lasers usage unless proper water cooling and specific power output setting was used (V ARMENGOL et al. 2000, REMI YAMAZAKI et al. 2001, KIMURA et al. 2002, B N CAVALCANTI et al.2003).

Most importantly some studies tested the efficacy of the bactericidal effect of the Er: YAG laser, particularly on Escherichia coli and Enterococcus faecalis and were happy to concluded positively (MORITZ A. 1999, Loma Linda University School of Dentistry.2010). However, a study conducted by OVE A PETERS et al (2011) showed activated disinfection did not completely remove oral bacteria from the apical root canal third and infected dentinal tubules, requiring some further investigation.

But how does PIPS® actually work?
After gaining access to the canal, an instrumentation of the canal is done to ISO #20 only. No further enlargement is necessary thus preserving tooth strength.
This is followed by PIPS® activation delivered from a cone-shaped fiber tip attached to a handpiece within an irrigating solution, either EDTA or NaOCl. The tip is inserted into the coronal third of the canal thus there is no risk of tip breakage from curved canals or undesirable apical extrusion of chemical irrigants possible with other laser endodontic methods (ROY GEORGE et al, 2008). The canal system is finally flushed clean with water and is ready to be obturated.

It is worthy it to check on the images provided by Dr Enrico DiVito and its team related to this new mechanism of root canal debridement. Please follow the link.

To sum up, this new technology seems to be very effective and efficient regarding root canal therapy. The ability to prepare/ instrument canals in a short period of time associated with great reduction of bacterial count (when compared to conventional root canal instrumentation) is absolutely promising.

References:

A. Husein. 2006. Applications of Lasers in Dentistry: A Review.

Takeda FH, Harashima T, Eto JN, Kimura Y, Matsumoto K. 1998. Effect of Er: YAG laser treatment on the root canal walls of human teeth: an SEM study.

Flavio Soares, Claudio H. Varella, Roberta Pileggi, Abi Adewumi, Marcio Guelmann. 2008. Impact of Er,Cr:YSGG Laser Therapy on the Cleanliness of the Root Canal Walls of Primary Teeth.

Kyoko Inamoto, Naoki Horiba, Shinpei Senda, Munetaka Naitoh, Eiichiro Ariji, Akira Senda, Hiroshi Nakamura. 2009. Possibility of root canal preparation by Er: YAG laser.

Roeland J.G. De Moor, Maarten Meire, Kawe Goharkhay, Andreas Moritz, Jacques Vanobbergen. 2010. Efficacy of Ultrasonic versus Laser-activated Irrigation to Remove Artificially Placed Dentin Debris Plugs.

E. DiVito, O. A. Peters, G. Olivi. 2010. Effectiveness of the Erbium:YAG laser and new design radial and stripped tips in removing the smear layer after root canal instrumentation.

V. Armengol, A. Jean, D. Marion. 2000. Temperature Rise During Er: YAG and Nd:YAP Laser Ablation of Dentin.

Reimi Yamazaki, Claudia Goya, Da-Guang Yu, Yuichi Kimura, Koukichi Matsumoto. 2001. Effects of Erbium, Chromium:YSGG Laser Irradiation on Root Canal Walls: A Scanning Electron Microscopic and Thermographic Study.

Yuichi Kimura, Kazuo Yonaga, Keiko Yokoyama, Jun-ichiro Kinoshita, Yoshiko Ogata, Koukichi Matsumoto. 2002. Root Surface Temperature Increase during Er: YAG Laser Irradiation of Root Canals.

Bruno Neves Cavalcanti, José Luiz Lage-Marques, Sigmar Mello Rode. 2003. Pulpal temperature increases with Er:YAG laser and high-speed handpieces.

Moritz A, Schoop U, Goharkhay K, Jakolitsch S, Kluger W, Wernisch J, Sperr W. 1999. The bactericidal effect of Nd:YAG, Ho:YAG, and Er:YAG laser irradiation in the root canal: an in vitro comparison.

Loma Linda University School of Dentistry. 2010. Final Report: Efficacy of Er: YAG Laser on Root Canals Infected with Enterococcus faecalis.

Ove A. Peters, Sean Bardsley, Jennifer Fong, Goldie Pandher, Enrico DiVito. 2011. Disinfection of Root Canals with Photon-initiated Photoacoustic Streaming.

Roy George, Laurence J. Walsh. 2008. Apical Extrusion of Root Canal Irrigants When Using Er: YAG and Er,Cr:YSGG Lasers with Optical Fibers: An In Vitro Dye Study.
Hyperlink: http://www.fotona.com/media/aurora/dokumenti/2010/11/pips_brochure_fotona_web.pdf

General Updates

Invasive Cervical Resorption. Coming Soon to a Tooth Near You.

August 30, 2011 Pat Caldwell 1 Comment

Invasive Cervical Resorption can spell disaster for a tooth if not diagnosed early.

The disease process known as Invasive Cervical Resorption (ICR) can be quite devastating for a tooth. The big problem for us as practitioners is that it’s difficult to identify ICR early. By far the most comprehensive article on ICR is by Geoff Hiethersay, (an Australian Endodontic legend) and this is the one article you need to read if you want more information than is contained in this post (Hiethersay 2004).

For dental resorption to occur, we need three things: 1. blood supply; 2. a stimulus; 3. breakdown or loss of the protective layer. When I refer to the protective layer, what I’m referring to is the pre-cementum externally, and the pre-dentine internally. It might seem odd that these seemingly frail tissues are able to protect tooth structure. The reason this protection occurs is that specific peptides named RGD peptides provide binding sites for the resorptive cells. These RGD peptides are bound to calcium salt crystals on mineralised surfaces. So when the resorbing cells reach the unmineralised pre-dentine or pre-cementum, they are unable to bind as no RGD peptides are present and thus, no resorption occurs.

So, it would seem that a lack of pre-cementum on the surface of a root may predispose to the development of ICR. This could happen due to trauma via a number of mechanisms such as scaling/root planing, internal bleaching, physical trauma or perhaps orthodontic movement of teeth. Dental trauma, internal bleaching and orthodontics have been associated with the development of ICR (Heithersay 1990). The condition also occurs without any pre-disposing factors, and it is suggested that a genetic lack of cementum (and therefore pre-cementum) may be present in those cases.

This is the same tooth as seen in the xray above. Invasive cervical resorption is both external and cervical in nature.

ICR is known by a number of other names and one of these is External Invasive Cervical Resorption. The “External” label is a reasonable addition as ICR is always external in nature. The resorption develops from cells in the periodontal ligament in the cervical region. This is the area that is most likely to have an absence of cementum from a developmental point of view at least. I mentioned that pre-dentine is also protective against ICR. The reason we know this is that in extensive cases the external resorption reaches the pulp, but the pulp is spared, protected by the pre-dentine. For this reason, even in extensive cases of ICR, the pulp usually remains vital. The resorptive tissue which invades the tooth seems to resist bacterial invasion. Certainly, you will not usually find a traditional periodontal pocket adjacent to the resorption.

I mentioned the three things that are required for resorption to occur. It’s obvious we have a blood supply and lack of protection, but where does the stimulus come from? The answer is that we don’t know. It has been hypothesised to be either inflammatory due to sulcular infection or a benign proliferative fibrovascular or fibro-ossesous disorder. That’s quite a mouth-full and I’ll leave it up to somebody much smarter than me to work out which one is correct. The cell that does the resorbing is similar in morphology to the osteoclast and may represent a functional variant of the same lineage.

A slight pink discolouration (arrow) is the only symptom from this tooth, which tested positive to pulp testing. This tooth is the same as seen in the xray and CBCT above.

Clincially, the tooth is usually completely asymptomatic. There may be a pink (or sometimes grey) discolouration of the crown but often the radiograph is the only indication that resorption is occuring. Radiographically, a mottled lucency is present and in advanced cases, there is a radiopaque line bordering the pulp chamber. Taking mesial and distal angled images will see the lesion move in relation to the pulp and this will differentiate the resorption from an internal resorption, as well as tell you if it’s positioned buccaly or lingually. Of course cone beam CT will also provide useful information.

Heithersay’s clinical classification is as follows:

Class 1 – small lesion with shallow penetration

Class 2 – well defined lesion close to coronal pulp

Class 3 – Deeper invasion to include the coronal third of radicular dentine

Class 4 – Large invasive lesion extending beyond the coronal third of the root

Class 1 and 2 lesions can be treated predictably, but the success rate in treating class 3 and 4 lesions drops dramatically. Treatment usually consist of using trichloracetic acid (TCA) to attempt to destroy the resorptive tissue via coagulation necrosis. The difficulty comes from the fact that the resorption is not usually confined to a discrete area and can have multiple feeding channels from well below the gingival margin. The lesion can also be treated surgically, but in practice it can be difficult to access and may even require bone removal to gain direct vision of the lesion. This rapidly gets destructive of both tooth structure and periodontal tissues which is why it is important to identify and treat (if indicated) the disease as early as possible. See Heithersay’s article for a description of the use of TCA and also other treatment options.

References:

Hiethersay G. Invasive Cervical Resorption. Endodontic Topics 2004, 7, 73–92

Heithersay G. Invasive cervical resorption: an analysis of potential predisposing factors. Quitessence Int 1999: 30: 83-95

Clinical Tips, Diagnosis of Pulpal Pathology

Pulp Testing – An Endodontist’s Best Friend

July 3, 2011 Pat Caldwell 13 Comments

Back when I was working as an Endodontist with the Australian Navy, I often mentored newly graduated dentists. There was an interesting interaction between us that would often occur. The junior dentist would come into my surgery with a question about diagnosis. They would explain a set of symptoms and then show me a radiograph. I would then ask what the pulp test result was. The new grad would then slowly back out of the room in order to return to the patient and conduct the test.

I’m not sure why the pulp testing was left off the list, but I hope I hope that by the time the junior dentist had finished their posting and moved on to a new posting that pulp testing is one of the most important tools allowing us to to diagnose. Unfortunately, there is nothing certain when it comes to pulpal diagnosis, especially when we get to the grey area of reversible/irreversible pulpitis. If we really want to know what’s happening in the pulp and periapical area of a tooth, we need to extract it, section it, and look at it under a microscope. But that’s not practical…….

Pulp testing is not 100% accurate. If it was, then diagnosis would be much easier, but it often gives us essential information that will confirm a clinical diagnosis. When it comes to vital pulps, electric and cold testing gives a positive result 81-86% of the time (Petersson & Kiani-Anaraki, 1999). In a partially or completely necrotic tooth, these modalities will give a negative result on almost all occasions. This is useful infromation to have at hand.

Here is an example from when I was doing my post-graduate training:

Images showing importance of pulp testing

Compare these radiographs. The image on the left is the pre-op and the image on the right is the two year review.

In the case above, we can see there is a definite lucency surrounding the lower right canine and central incisor. The lateral incisor may also be involved. Pulp testing with both cold and EPT revealed the canine was testing negative and the incisors were testing positive. As only the canine was testing negative, I only treated the canine. At the two year review, we can see that the lesion has healed and normal periradicular architecture has been re-formed around the vital incisors. If we just worked from the x-rays, we’d probably treat all three teeth, and subject the patient to unnecessary treatment. This is a pretty simple lesson.

Here are the keys to successful pulp testing:

1. Make sure the teeth are completely dry and isolated with cotton wool rolls;

2. Place the tip of the pulp tester on tooth structure, not restoration, and use a small (perhaps half of a) cotton pellet or endo sponge;

3. Start your test with a tooth that you expect will give a normal result and is not involved with the area in question. This will allow the patient to get a feel for what a normal response is;

4. Test with both cold and EPT. If the patient is experiencing symptoms such as a hyper-response to hot foods/liquids, then use hot as well.

In my surgery I have the pulp tester sitting right next to me, along with things like the apex locator and endo motor. We use it that often.

References:

Petersson KS, C. Kiani-Anaraki, M. Evaluation of the ability of thermal and electrical tests to register pulp vitality Endod Dent Traumatol 1999;15:127-131.

Dental Trauma, General Updates

Endospot Sites of Note: Dental Trauma Guide

May 28, 2011 Pat Caldwell Leave a comment

Jens Andreasen and his team have compiled all their knowledge at created the Dental Trauma Guide. If you haven’t seen this before, go and have a look. It’s easy to use and might just help you out in an emergency dental trauma situation.

The site also includes all the references for those of you who need them.

I recommend you bookmark it at: http://www.dentaltraumaguide.org/

Clinical Tips, Endodontic Preparation Techniques, General Updates

Endospot Cases of Note. Case 1. C-Shaped Canal.

May 25, 2011 Pat Caldwell 1 Comment

Welcome to the first Endospot Case of Note. This case is of a C-Shaped lower molar and I’ve tried my best to highlight the interesting aspects of the case, explain what can be seen using our diagnostic tools, and also how to treat these cases. As usual, I would love to hear your thoughts and you can leave a comment below.

If you want to review the anatomical variations of C-shaped canals, I recommending reading the following references:

Fan B, Cheung GS, Fan M, Gutmann JL, Bian Z (2004). C-shaped canal system in mandibular second molars: Part 1 Anatomical features. Journal of Endodontics 30(899-903.
Fan B, Cheung GS, Gutmann JL, Fan W (2004). C-shaped canal system in mandibular second molars: Part II Radiographic features. Journal of Endodontics 30(904-8.

This video can be watched in HD on Youtube. Please enjoy!

httpv://www.youtube.com/watch?v=dF3JUsY_k8I

Endodontic Preparation Techniques, General Updates, Irrigation

First Impressions of the Self Adjusting File

April 13, 2011 Pat Caldwell 10 Comments

I had the opportunity during the Australian Dental Association Congress to get my hands on the new Self Adjusting File. It’s not yet available for purchase in Australia, but will be in a couple of months. The SAF comes in 21, 25, 31mm lengths and two widths.

The three lengths of the Self Adjusting File

To be honest, there is a lot of cynicism out there amongst Endodontists regarding this instrument, mainly because of the manufacturer’s claim that you only require one SAF file to prepare the canal. I think some of the cynicism is driven by the fact that both Dentsply and VDW have recently released their own single file reciprocating systems. The cynicism of Endodontists regarding single file systems is warranted in my opinion. Realistically no one single round file is going to be adequately able to clean and shape the complex anatomy that we are faced with in root canals. They may also force the heavily infected contents of the coronal part of the canals apically and they may not give sufficient time and bulk of irrigant to allow cleansing. When you read the fine print. even the manufacturers will admit that certain canals with particular anatomy preclude the use of the reciprocating files.

In the case of the SAF, the manufacturer told me that they were not selling the system as something that will make preparation easier, cheaper or faster, but rather increase the quality of the preparation. This is probably a good line to take if you want acceptance by the Endodontic community.

OK, on to the SAF. Basically, the file is made of a NiTi mesh with a coating that is designed to “sandpaper” the walls of the canal. The mesh compresses to fit the shape of the canal. I admit I thought the engineering concept behind the file was pretty cool. The manufacturer told me that the designer was involved in the production of cardiac stents and utilised the basic design concept of these. I made the short video below to give you an idea of how the file behaves.

httpv://www.youtube.com/watch?v=UGZZP6_vtN0

On using the file, my first impression is that I’m not going to be out of a job as an Endodontist due to the release of the SAF. You still need to find the canals and prepare to a size 20 at the apex before using it. If you don’t prepare a path, then you’ll end up blocking the canal with debris, just like can be done with rotary files. That said, the ability of the file to prepare these irregular plastic shaped blocks was impressive. The block has an oval shaped canal with fins in it and a fine red coating on the inside. In a one minute session, the file pretty much cleaned all the red stuff off the inside.

I took one of these blocks back to my surgery to see how well I could clean it using traditional methods and after about four minutes of using rotary Ni Ti, hand files, and ultrasonic files, I still couldn’t get the block as clean as I did with the SAF. I’m not sure how well the apical part of the preparation was phycially cleaned by the SAF. If I was using the SAF, I think I’d probably end up gauging the apical portion after using SAF and maybe finishing off with rotary files to enlarge it if required.

Plastic block prepared by rotary NiTi on the right and SAF on the left. I took this image from the manufacturer's online powerpoint presentation, but it mirrors the experience I had.

There are two aspects to the SAF system. The first is the ability of the file to clean, and the second is the fact that it is constantly pumping fresh NaOCl through the centre of the file. It may well be that this is the most useful/best aspect of the system. Often in our literature and certainly by manufacturers an improperly greater emphasis is placed on the mechanical preparation of root canals systems compared to our efforts to actually clean the canals of tissue and microorganisms. In a previous post I’ve mentioned the benefits of passive ultrasonic irrigation, and I think the continual deposition of fresh NaOCl into the canal during preparation has great potential.

There isn’t really much research available on the SAF. I could find seven papers in pubmed, all bench top studies (see the end of this post for a complete list). The general outcome of these is that the SAF does a reasonably good job of debriding most areas of the canals under the conditions of the studies, and some nice microCT images were produced. One study (remember these are in vitro, not in actual clinical situations) found the SAF was significantly better at disinfecting canals infected with e. faecalis than rotary NiTi (Siquiera Jr et al. 2010). I guess we need to see more research and time will tell if the SAF is able to disinfect canals better than what we currently have available. My feeling is that it’s a possibility.

httpv://www.youtube.com/watch?v=bWhd8Mgbtmw&NR=1

Above is the manufacturer’s description of the irrigation function of the SAF

The irrigation part of the SAF system is also the biggest downside. In order to use it as described, you have to buy the electronic pump that goes with it. The pump has a timer to make sure you use the file for the full minute, so I guess that’s a good thing. However, I believe that the pump will be susceptible to failure as you manage to spill the NaOCl over it as you repeatedly fill the reservoir. The manufacturer admitted this fact and impressed that the correct funnel needed to be used.

The pump is also another contraption that we have to plug in and put on our benchtops (along with our endo motor, ultrasonic unit, pulp tester, apex locator, system B, obtura etc etc), not to mention another foot pedal on the floor. To be honest, having to buy the pump might stop me from buying the whole unit. We did question the manufacturer on whether we could just use a a syringe filled with NaOCl attached to the tubing which connects to the file, and although he obviously wants us to buy the pump, I think the answer is yes. This would be a much neater and more acceptable to me than having the pump on the bench.

The SAF pump. Another machine to clog up our benchtops.

One of the big concerns with rotary NiTi files is obviously the issue of fracture. My friends and I tried very hard to break the SAF and were successful. It did take a while though, and to it’s credit, when the file broke, it was just one of the arms that breaks, leaving the whole file retrievable. I do stand to be proven wrong, but I think that it would be quite unlikely that a separate portion of the file would break and lodge in a canal requiring removal.

Mode of failure of the SAF. This image was taken from manufacturer's powerpoint presentation, but is exactly what I saw during the trial.

The business end of all these things are how much they cost. If you buy in bulk, the cost of one of these files in Australia is going to be about AU$70. That’s about US$73 at today’s rates. So, they are quite expensive, especially if you plan to use additional rotary files to further prepare the apical area, you break one before you finish the tooth or you need to use both the larger and smaller width files to complete multiple canals in one tooth. You also need to buy a special handpiece or handpiece head, plus the irrigation system if you go by the manufacturer’s instructions. This might scare a few people away and into the arms of the single file reciprocating systems. I’ve previously stated that the reciprocating files may become a part of our armamentarium for particular cases, and it may be that the SAF fits into this category.

My overall impression of the SAF, despite being cynical to begin with was a positive one and I think that this system has potential to do more for us than the reciprocating files. Stephen Cohen, author of Pathways of the Pulp will be in Australia in June running workshops on the system, so we’ll get another look at it then. The SAF is certainly no panacea for endodontically infected teeth, and preparing canals that are already opened to a size 20 file is actually the easiest part of an Endodontist’s day. That said, if further evidence comes through indicating that the SAF system does in fact kill more bacteria in the root canal than our current systems, then I guess we’ll all want one.

Pat Caldwell

References: Hof R, Perevalov V, Eltanani M, Zary R, Metzger Z. The self-adjusting file (SAF). Part 2: mechanical analysis. J Endod. 2010 Apr;36(4):691-6.

Metzger Z, Teperovich E, Cohen R, Zary R, Paqué F, Hülsmann M. The self-adjusting file (SAF). Part 3: removal of debris and smear layer-A scanning electron microscope study. J Endod. 2010 Apr;36(4):697-702.

Metzger Z, Teperovich E, Zary R, Cohen R, Hof R. The self-adjusting file (SAF). Part 1: respecting the root canal anatomy–a new concept of endodontic files and its implementation. J Endod. 2010 Apr;36(4):679-90.

Paqué F, Peters OA. Micro-computed Tomography Evaluation of the Preparation of Long Oval Root Canals in Mandibular Molars with the Self-adjusting File. J Endod. 2011 Apr;37(4):517-21.

Peters OA, Boessler C, Paqué F. Root canal preparation with a novel nickel-titanium instrument evaluated with micro-computed tomography: canal surface preparation over time. J Endod. 2010 Jun;36(6):1068-72. Epub 2010 Apr 10.

Peters OA, Paqué F. Root canal preparation of maxillary molars with the self-adjusting file: a micro-computed tomography study. J Endod. 2011 Jan;37(1):53-7. Epub 2010 Oct 8.

Siqueira JF Jr, Alves FR, Almeida BM, de Oliveira JC, Rôças IN. Ability of chemomechanical preparation with either rotary instruments or self-adjusting file to disinfect oval-shaped root canals. J Endod. 2010 Nov;36(11):1860-5. Epub 2010 Sep 16.

Diagnosis of Pulpal Pathology

The Endospot Simple Guide to Pulpal and Periapical Diagnosis Part 2

March 21, 2011 Pat Caldwell 2 Comments

In this post we discuss a simple and practical method of classifying periapical pathology that can be used in practice on a daily basis.

What’s Your Diagnosis?

Listen to the audio version here (5 mins, 50s) : Pulpal and Periapical Diagnosis

References referred to in the episode:

Abbot P. 2004. Classification, diagnosis and clinical manifestations of apical periodontitis. Endodontic Topics 2004, 8, 36–54

Andreasen FM. Transient apical breakdown and its relation to color and sensibility changes after luxation injuries to teeth. Endod Dent Traumatol. 1986 Feb;2(1):9-19.

Eliasson S, Halvarsson C, Ljungheimer C. Periapical condensing osteitis and endodontic treatment. Oral Surg Oral Med Oral Pathol. 1984 Feb;57(2):195-9.

Johnson W. 2002. Color atlas of Endodontics. W.B. Saunders, Philidelphia

Episode Transcipt:

Welcome to the Endospot episode 3. We’re now coming to you from Brisbane, Australia.

Well, the big news for me since the last episode is that I’ve moved home from Shanghai and have set up practice in Brisbane, Australia. It’s been an interesting process setting up a practice. There are lots of buying decisions to be made and I’ll probably talk about those in some upcoming blog posts so get on to the website at www.endospot.com and remember you can sign up to have the blog posts delivered directly to your email box.

Today we’re going to quickly go through the clinical classification system that I use for periapical pathology. If you’ve listened to the last episode, you’ll remember that I like to split up my diagnosis into pulpal and periapical diagnoses. If you haven’t listened to it, do so after this podcast is finished.

As with the pulpal diagnoses, there are quite a few different systems for classifying periapical conditions, and the one I like to use is similar to that published in Johnson’s clinical atlas of endodontics. I like it because it’s simple and easy to apply clinically, and will definitely help you arrive at a treatment plan.

The first diagnosis is the obvious one, “healthy periapex”. Usually, this will accompany a healthy pulp, there will be no symptoms of pain, no tenderness to percussion or palpation, and radiographically, the apex will appear completely normal. This is the diagnosis we like to make.

Diagnosis number two is “acute apical periodontitis”. This is an acute diagnosis, so by definition, there will be pain associated with this. And that means pain on percussion and possibly biting as well. Radiographically, the apex should appear normal or at most there might be some thickening of the PDL space. Importantly, you should realize that acute apical periodontitis will often occur along with pulpitis because when inflammation of the pulp occurs, we get an associated inflammation of the periapical tissues. But, the one to watch out for is where we have a normal pulp, and the periapical area is inflamed due to something like occlusal trauma or acute sinusitis. Obviously in this case performing root canal treatment isn’t going to lead to resolution of the symptoms.

The third diagnosis is ‘chronic apical periodontitis’. So the difference here is the word chronic. By definfition this is not a painful condition. This diagnosis is almost always accompanied by a necrotic pulp and the infection in the pulp is causing a periapical lesion which is picked up on a radiograph. In most cases, the pulp test will be negative, but occasionally, if the pulp is only partially necrotic, then you may still get a positive pulp test. The tooth may be slightly tender to percussion as well.

Our fourth diagnosis is ‘acute periapical abscess’. So this is an acute diagnosis so we have pain, the pulp will be necrotic so we’ll usually get a negative pulp test, there should be a lucency obvious radiographically. With a diagnosis of abcess the tooth will be very tender to percussion, often even with a gentle finger tap, and the tooth may be painful to bite on and may even be elevated in it’s socket. There can be localized swelling and lymph node enlargement as well.

Our fifth diagnosis is “chronic apical abscess”. Again because this is a chronic condition, there shouldn’t be symptoms of pain, and the key finding here is that of a sinus tract. The pulp will usually be completely necrotic, so expect a negative pulp test and a radiographic lucency. Because this diagnosis is due to the tooth being associated with an abscess, but the pus that is forming is being released through the sinus tract, these teeth are rarely symptomatic at all. You should be able to place a GP point into the sinus tract and take an x-ray to trace the sinus to a root tip.

The sixth and final diagnosis I want to talk about today is condensing osteitis. You don’t find a lot of information about this in the literature. It’s a diagnosis that you make radiographically by seeing an increased density of bone around an apex. Usually this will be associated with a pulp that is chronically inflamed but still vital, and the body has responded by increasing the bone density around the apex. I’ll put a reference for a case series in the show notes on the website.

So that’s it for periapical diagnosis. You need to be aware that twhat I’ve described is is a simple clinical diagnosis classification system designed to help you determine what treatment should be provided. There are always exceptions and you might find situations that don’t exactly fit for example when an abscess forms very quickly after pulpal necrosis but the periapical lesion doesn’t expand to a size that produces a lucency on a radiograph. Certainly the diagnoses we discussed tend to require a radiographic component, but it should be the clinical picture and symptoms that your patient is describing which heads you towards your diagnosis. There are also a bunch of conditions that can present as a lucency on an xray which are not endodontic in origin so again, your clinical history and tests should fit the radiographic appearance.

If you want a thorough review of the interaction of the periapical pathologies then go and grab Abbot’s article in Endodontic Topics, reference will be in the show notes. There are also some less common situations where other diagnoses are appropriate such as transient apical periodontitis and if you want to look that up I’ll put the reference for that in the notes too.

And in the meantime, remember you can go to the site and sign up to receive the endospot directly into your email box. That’s it for today. I’ll look forward to speaking to you next time.

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General Updates

Introducing The Root Canal Anatomy Project

March 11, 2011 Pat Caldwell 1 Comment

Professor Marco Versiani

Over in Sao Paolo, Brazil, Professor Marco Versiani and his team have been busy scanning teeth with MicroCT. MicroCt is a an exciting tool for the examination of tooth anatomy, and is particularly useful for looking at root canal anatomy. The result of Prof. Versiani’s work is the Root Canal Anatomy Project. They’ve put together a website where you can go and have a look at the results of their work. It’s a great source of information and provides nice 3D views of pulp anatomy. Best of all, it’s free and Prof. Versiani will allow you to use the content for education purposes. Below is a sample of the work, and below that is the terms of the free use of the content:

httpv://www.youtube.com/watch?v=5fM95Uo_Sts&feature=player_embedded

The images and videos of “The Root Canal Anatomy Project” blog were developed at the Laboratory of Endodontics of Ribeirao Preto Dental School – University of Sao Paulo – and may be freely used for attributed noncommercial educational purposes by educators, scholars, student and clinicians. It means that all material used should include proper attribution and citation (http://rootcanalanatomy.blogspot.com/). In such cases, this information should be linked to the image in a manner compatible with such instructional objectives.

Clinical Tips, Endodontic Preparation Techniques, Irrigation

1 Minute to Bacteria Free Canals. Here’s How.

February 23, 2011 Pat Caldwell 4 Comments

Endodontic Microbes. Who needs them?

OK so a patient has come to see you complaining of toothache. It’s root canal time. You open up the lower right first molar and find a necrotic pulp. You’ve isolated well and done a nice endodontic preparation. Length is good and you’re happy with the sizes of your apical preps. You’ve been irrigating with plenty of sodium hypochlorite and used a final rinse of EDTA. Job done right?

Think again. In the vast majority of teeth, canals are not round, and as such there are going to be vast areas that are still harbouring debris and microbes. Just take a look at some of the microCT produced by Paque et al after preparation with rotary Ni Ti (Paque at al. 2010). It’s quite clear in these images that a good proportion of the original canal space remains untouched by our instruments.

So, hopefully, our irrigant is managing to get into these nooks and crannies? Well it will, but even after irrigation, there is still going to be significant debris from preparation (mushed up dentine, bacteria, necrotic pulp remnants) hiding away in fins, apical delta and especially in isthmuses.

I recommend you check out the work by Burleson and colleagues for some nice images on what can be left behind (Burleson et al. 2007). These guys conducted a randomised controlled trial (nice and high on the level of evidence) and compared preparation and irrigation alone, or with the addition of 1min of passive ultrasonic irrigation (PUI). They used the mesial roots of infected lower molars and then extracted the teeth to examine how much debris was left behind. Check out the table below to see the results on cleanliness of the canals at various levels from the apex. The isthmus especially is full of debris without PUI.

Cleanliness of Canals at various levels from the apex. Pay special attention to the number in the isthmus.

Interesting right? It’s even better when you see the images in their article and realise just how much is being left behind when you only rely on irrigation.

I know what you’re thinking though. It’s bacteria that we’re concerned about, not debris. Well, Burleson’s colleagues thought of this, and conducted a separate study, I assume on the same teeth, using microbiological sampling to see what they could find (Carver et al. 2010). They concluded that PUI resulted in a significant reduction in colony forming units and positive cultures. In fact PUI was, “7 times more likely to yield a negative culture”.

So, it seems that PUI is something worth doing, and it’s certainly part of my routine. If you haven’t heard of it, I’ll explain what it is. PUI is simply the placement of an ultrasonically activated file into the canal filled with irrigant. There is some debate over how it works exactly, but acoustic streaming seems to be the key. This basically means moving the solution around so that fresh sodium hypochlorite gets into areas that needles won’t push it. The important point here is that the ultasonic file has to be loose in the canal. Touch the canal wall and acoustic streaming stops.

Personally, I use the Irrisafe from VDW because it’s easy. Just screw it on to your US unit and place it in the canal. The irrisafe is “smooth” i.e. it doesn’t have the sharp cutting edges that files do, so it is safer in the canal (Hence the name – smart huh). Here are my three keys to PUI:

1. Use a low power setting as recommended by the manufacturer. You risk fracturing the ultrasonic file otherwise;

2. Keep the file loose in the canal and don’t push it too deep;

3. Replenish your sodium hypochlorite as you go.

The Irrisafe. Attach it to your ultrasonic and kill more bugs.

Acoustic Streaming in Action

I generally have my DA using a syringe to supply sodium hypochlorite and suction while I run the ultrasonic in the canals. If you don’t have a stand alone ultrasonic unit where you can easily control the power, then I wouldn’t risk using an ultrasonic file. You can achieve the same result by just holding a normal scalar tip against a size 10 stainless steel file. This is obviously much cheaper as well. Just be careful not to put the file too deep into the canal or you might actually damage the canal walls and ruin your nice preparation.

There are other methods for activating irrigant such as the Endoactivator and the Endovac. These work slightly differently. The Endoactivator is a sonic machine and has disposible polymer inserts. It seems very safe to me, but there isn’t much in the literature indicating that it is better at killing bugs than other methods (Huffaker at al. 2010), and it is not as effective as PUI at removing calcium hydroxide from canals (Wiseman et al. 2010).

This is just part of the Endovac system

The Endovac shows promise. It relies on a vacuum to remove irrigant that is being supplied by a needle deep in the canal. That means there is no positive pressure. One clinical trial showed that post-op pain was reduced after using the Endovac compared to needle irrigation (Gondim et al 2010). It is a bit of a contraption though and I have enough machines clogging up my surgery. I am waiting to see some studies comparing PUI directly to Endovac and Endoactivator before I give up my proven method of cleaning the canals.

Next time you finish a prep, grab your ultrasonic and give the canal a bit of a shake up. It’s impressive to see how much more debris you can get out when you irrigate again.

References:

BURLESON A, NUSSTEIN J, READER A, BECK M. 2007. The in vivo evaluation of hand/rotary/ultrasound instrumentation in necrotic, human mandibular molars. J Endod. 33: 782-787

GONDIM E, SETZER F, BERTELLI C, KIM S. 2010. Postoperative Pain after the Application of Two Different Irrigation Devices in a Prospective Randomized Clinical Trial. J Endod. 36:1295–1301

HUFFAKER S, SAFAVI K, SPANGBERG L, KAUFMAN B. 2010. Influence of a Passive Sonic Irrigation System on the Elimination of Bacteria from Root Canal Systems: A Clinical Study. J Endod. 36:1315–1318

PAQUE F, BALMER M, ATTIN T, PETERS OA. 2010. Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. J Endod. 36(4): 703-7

WISEMAN A, COX C, PARANJPE A, FLAKE N, COHENCA N, JOHNSON J. 2011. Efficacy of Sonic and Ultrasonic Activation for Removal of Calcium Hydroxide from Mesial Canals. J Endod. 37:235– 238

Endodontic Preparation Techniques, General Updates

What’s New in Endodontics for 2011?

January 27, 2011 Pat Caldwell 1 Comment

Wishing you happy and successful endodontics in 2011

Happy New Year to you wherever you are in the world. Here at the Endospot we like to keep you up to date with the latest in endodontic technology, so for the first post of the new year we’ll be discussing a new trend in endodontic file systems that seems to have been taken up by a few of the big companies. Previously I’ve mentioned adding additional files to your instrumentation protocol in order to create a smooth glide path. Now it seems that in the quest for an endodontic system that is faster and uses fewer files, the concept of a reciprocating file has been revisited.

Back in 1985, James Roane published an article on the balanced force technique and this is compulsory reading for any aspiring Endodontist (Roane et al. 1985). I won’t go into an explanation of the technique, but it uses a clockwise, anti-clockwise, clockwise motion to negotiate curved canals using stainless steel files. This process became motorized with the Introduction of the M4 handpiece, which is a reciprocating handpiece for use with stainless steel files. This handpiece has limited application but some Endodontists still use it for by-passing ledges in curved canals.

Back to the topic at hand. Dr Ghassan Yared has taken a step back to this concept of reciprocation to see if nickel titanium endodontic files can be used in a reciprocating motion to prepare canals. He published an article in the Journal of Endodontics in 2008 with his initial thoughts and experiences (Yared, 2008). At that stage he was using a single Protaper F2 to prepare canals. The canals were initially negotiated with a #8 hand file to length and then the reciprocating F2 file was used with a light apical pressure to prepare the whole canal. Of course, due to the variability of root canal anatomy, sometimes a larger file was needed to complete preparation – for example in distal canals of lower molars. The article also mentioned that sometimes the glide path had to be prepared with a #10 and #15 before the F2 would progress to length. These facts sort of negate the concept that this is truly a “one endodontic file system”, but I guess that in most of the cases, only one file was used. Anyway, have a read of the article yourself for a full run down.

Although there is limited research behind the process, there now exists a commercial version of the reciprocating files, developed with Dr Yared’s input (I’m not sure of his commercial interest in the system). A new file has been developed to replace the Protaper file. Apparently the use of the protaper had a couple of drawbacks in that it could be susceptible to fracture due to cyclic fatigue and a glide path was required.

The new reciprocating endodontic file system (VDWs is called RECIPROC) contains three files with a #25, #40 and #50 tip and is claimed to cut more efficiently than the protaper. IN cross-section, the file is similar in appearance to an Mtwo file. In instructional material Dr Yared claims that in the majority of canals only require one of these new endodontic files and that no hand filing is required. You do need to use a hand file to determine which reciprocating file to use.

Only one file to prepare a canal and no requirement for hand filing. Sounds like an endodontic dream right? Further reading of the material does in fact indicate that in some curved canals a glide path is still required using hand files and where there is an abrupt apical curvature hand files must be used to complete the apical prep, so unfortunately the system is by no means a panacea.

Apparently there is unpublished data available indicating that the reciprocating endodontic file system is faster at preparing canals, easier to learn and results in fewer procedural errors than rotary NiTi, so hopefully this data will be published soon so that we can assess it.

As well as GDW, Dentsply also has a reciprocating system on the market. I’ve had an opportunity to briefly trial the VDW and Dentsply files in plastic blocks. I’m told the files will be available commercially in Australia in a few months time so we’ll be able to test them out properly at that point and provide feedback.

If any readers out there have had experience with these files, I’d love to hear what you have to say. In the meantime, we’ll wait and see what research is published over the coming years. My take on this concept is that it does make sense to use the files in a reciprocating manner and I am looking forward to trialing the system. We really should be approaching each individual canal that we prepare as a unique task though, so I’m always a bit dubious about an endodontic system that has only a few files, but if the studies show promising results, this could become an important part of our armamentarium.

Roane JB, Sabala CL, Duncanson MG. The “balanced force” concept for the instrumentation of curved canals. J Endod. 1985 May;11 (5):203-11

Yared, G. Canal preparation using only one Ni-Ti rotary instrument: preliminary observations. Int Endod J. 2008 Apr;41 (4):339-44

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