How YoU view the Profession

The D.O.M. and Post Coronal seal

Mon, 3 Dec 2007 03:16:48 -0800

One of the findings in endodontic literature is that the Coronal seal (Removing the ability of contamination of the obturation by saliva and oral bacteria) is a key in the ongoing success of endodontic treatment. Some studies have shown that exposure of the Gutta Purcha to bacteria can in as little as 28 days allow for bacteria to travel the entire length of the tooth, allowing for failure of the treatment to become a possibility.

J Endod. 2002 Nov;28(11):762-4.Click here to read Links
An assessment of microbial coronal leakage of temporary filling materials in endodontically treated teeth.
Balto H.

King Saud University, College of Dentistry, Division of Endodontics, Riyadh, Kingdom of Saudi Arabia.

This in vitro study evaluated the microbial leakage of Cavit, IRM, and Dyract when used as temporary filling materials after root canal treatment. The degree of coronal leakage was assessed by using a microbiological marker consisting of Streptococcus faecalis and Candida albicans. For each of the two organisms, a set of 15 maxillary premolars were prepared chemomechanically and obturated with thermoplasticized gutta-percha. A 3.5-mm thick layer of one of the three temporary filling materials was inserted in the access cavities of the teeth from each group (each group was compromised of five teeth). The control teeth (four positive and four negative) lacked any filling material over the gutta-percha, whereas the orifice and the apical foramen of the negative control were completely sealed with nail polish. Each tooth was placed in a well of a 24-well tissue culture plate and embedded in trypticase soy broth and 0.5% Bactoagar. An organism suspension was inoculated in the access cavity, and microbial penetration was detected as an increase in turbidity of the broth. At the end of 30 days, the results showed that all positive control teeth leaked within 1 week, whereas those that served as negative control remained uncontaminated throughout the test period. With both organisms, IRM started to leak after 10 days, whereas Cavit and Dyract leaked after 2 weeks.

 
Others have shown, the temporary restorations have far less ability to provide a coronal seal than a permanent restorative material on a completed endodontic procedure.

J Endod. 1999 Mar;25(3):178-80.Links
A comparative study of four coronal obturation materials in endodontic treatment.
Uranga A, Blum JY, Esber S, Parahy E, Prado C.

Faculty of Medicine and Odontology, University of Basque Country, Lejona, Spain.

The aim of this study was to compare, in vitro, the ability of temporary versus permanent materials to seal the access cavity. Eighty human maxillary single-canal teeth were prepared biomechanically and obturated with gutta-percha and an endodontic cement AH Plus, using the warm vertical compaction technique. All access cavities were sealed with 1 of 4 materials (Cavit, Fermit, Tetric, or Dyract). Microleakage was assessed by methylene blue dye penetration. The teeth were submitted to 100 thermocycles, with temperature varying from 0 degree to 55 degrees C. The greatest degree of leakage was observed with the temporary materials (Cavit and Fermit). There was a significant difference (p < 0.05) in leakage between all materials except between Dyract and Tetric. This suggests that it may be more prudent to use a permanent restorative material for provisional restorations to prevent inadequate canal sealing and the resulting risk of fluid penetration.

PMID: 10321182 [PubMed - indexed for MEDLINE]

It is clear from the literature that the quality of the coronal seal can affect the longevity of the endodontic therapy. All of us have witnessed a seemingly successful endodontic case radiographicallly become reinfected and upon access into the tooth, discovered leakage and bacteria coronally that was responsible for the reinfection of the canals and for the reoccurrence of the periapical pathology.

In completing an endodontic case the micrsoscope can help with the ability to provide a nice clean and solid coronal seal. The technique is as follows:

1.Coronal seal is so important to preventing reoccurrence of periapical pathology.
2.Clean up of pulp chamber involves isopropyl alcohol in an Ultradent syringe.
3.Slowspeed round burs, or high speed diamonds to clean up Gutta Percha.
4.Flowable over the GP at the pulpal floors, corebuildup in composite afterwards. Some like Amalgam for seal

The key in these cases is to see a nice void free interface leading from the endodontic therapy to the access of the tooth. This should be done at the completion of the treatment to give the greatest success to long term health for the tooth.  The above procedural guide combined with the microscope which allows for easier viewing of the access of the tooth and careful placement of restorative materials provides for a nice radiographic flow of materials from the pulpal floor coronally.

Stay tuned this week for further cases demonstrating the effectiveness of the microscope for endodontics.

Uncovering more anatomy

Sat, 1 Dec 2007 07:15:21 -0800

In today’s blog we look again at a couple of more cases focussing in on the role of the microscope in locating Portals Of Entry to the roots of the teeth. The cases below are my own of varying ages to show the photography possible and the ability if you know where to look to find canals.

In the first case we see an upper first molar with 4 canals and see where the white line leads us to uncover the MB2 which as usual is located mesial to the line connecting MB1 and the Pal canals. The 2nd case is an upper 2nd molar and with the microscope you will soon become uncomfortable only finding one MB canal as well. There often as John Stropko shows in his study, 4 canals in upper 2nd molars as well.

Troughing for Extra Portals of entry (POE)- a Long Review.

Fri, 30 Nov 2007 22:20:43 -0800

One of the confusing things when you get a microscope is what the heck you are looking at when you suddenly are getting the gift of actually standing inside the endodontic access ( it seems like that) and getting this huge magnified and illuminated view of the inside of the tooth. With time you begin to understand better what you are actually looking at, and understanding all the visual information that you have never seen before. Once the puzzle of whitelines, dentin maps, pulp stones, and other oddities of the pulp chamber become better understood and more frequently seen then you know better where to search for the canals.  John Khademi has shown repeatedly cases where extra canals are found. This first case is John’s taken from Dental Town. If you ever get a chance to see some of what John has to teach then I highly encourage you to listen to him lecture. He is a very bright man, with a great ability to teach.

In these first 3 collages of photos (TDO software) you can see a poorly fitting resin restoration filling the access cavity on a previously accessed first molar. The troughing for the small white dot was 12mm from the occlusal surface and look how far the canal moved from initial location to where it dropped into the MB2. This is why MB2 canals are so hard to enter unless you trough for the canal more mesially than the MB-P line that we talked about yesterday in the Blog. The next case shows how troughing for the little white lines can yield more than just one extra canal.

Again two more images from two other cases showing 6 canals Portals of Entry. Now granted these cases can merge together apically, but the more tissue and bacteria we access the greater the opportunity for success. Again these cases are from John Khademi. My 6 canal molar is later.

As you can see from my case 3 canals were found in the mesial root of this lower molar and 2 canals in visit one of instrumentation. At appointment 2, another distal canal which merged with the other one was located.

These cases show that the molars can provide more than the number of canals we all learned were supposed to be in these teeth. Careful analysis with the microscope can provide for the routine location of extra anatomy and the more we find the greater the chance for success (Unless of course the first three are non vital and the last three bleed profusely and set the apex locator off long every time they are explored!!).
 Til next time......happy scoping.

Glenn

Access with the Operating Microscope- The elusive MB2

Wed, 28 Nov 2007 20:45:58 -0800

Many dentists purchase the operating microscope solely to be used in the early stages of endodontics to locate canals in molars with greater ease. The combination of magnification and illumination possible with the scope helps incredibly with the visual acuity possible in endodontic access.   The most common tooth to fail after initial endodontic therapy is the upper first molar and the sobering study by John Stropko published in the JOE in 1999 which looked at 1732 maxillary molars and found that 93% of them when viewed with the microscope had 4 canals. The dentist employing the microscope stops looking for certain numbers of canals (ie 2 canals in an upper first premolar, 3 canals in a first and 2nd molar ) and starts taking what the scope gives. The emphasis shifts with improved visual acuity to searching instead of finding. Soon the initially confusing “dentin map” of the pulp floor provides clear information as to where to search for “hidden “ anatomy.   White lines (tissue) the grays of the pulp floor, the dark shadows providing the pathway to pulpal portals of entry become exciting. Bleach bubbling at the POE, deep isthmuses, and branches all cause the clinician to re-evaluate when is enough. Those of you using the scope understand the prose above, and nod as you realize that the scope changes everything when it comes to endo.

Predictably leads to confidence which in turn leads to enjoyment for this discipline which causes many “Naked Eye Dentists” great grief. You realize one day that complications from intraoperative iatrogenic errors (perforations, missed canals, canals that cannot be negotiated or located) all start to drop in occurrence. As the ability to understand the visual information that the scope provides becomes understood (initially its kind of confusing), endodontic access becomes kind of enjoyable. A puzzle or riddle with a reachable conclusion.
 The scope in my opinion helps in at least 5 areas of endodontic access:

1.Access opening and straight line access to canals.
2.Understanding the Dentin Map of the pulpal floor.
3.Localization of extra pulpal anatomy.
4.Determining the extent and prognosis for cracked and difficult to restore teeth.
5.Providing ideal isolation from oral contamination.

We were all taught in dental school that the location of the MB2 when it did exist was on a line drawn between the MB 1 and Palatal canals. Well nothing could be further from the truth. Dr. John Khademi offers some tremendous teaching material on endodontic access. The following drawings are from his work. As you can see the location of the MB2, and MB3 canals often lie mesial to the line drawn between the MB1 and MB2. The initial direction of this canal can be back towards the MB2 and necessitates that the mesial wall of the access be brought towards the mesial to uncover these canals. Once located often troughing with ultrasonics (TUFI, Carr Killer tips , BUC 2 and 2a) or Munce or Muller burs are needed to deepen the initial trough at least 2-3 mm before the MB2 ends its mesial and palatal direction to gain a straighter path back into the MB root.

The following illustration demonstrates (again courtesy of Dr. Khademi) why the MB2 canal is often separate in older patients and more difficult to negotatiate with the age of the patient.

As the patient ages the clinician must rely on the scope more and more to uncover the calcified pulpal anatomy that tends to close from coronal to apical portions of the root. Thus if there is enough magnification and illumination to be confident to continue troughing one can feel confident that eventually the canal will “open up” and allow for instrumentation and penetration of the deeper parts of the root allowing for irrigants to “clean” these portions of the tooth.

The pulpal floor with its grey pathways (dentin map) and white lines (tissue) show where troughing and careful searching should occur.

In the above case a vital upper first molar is accessed (not the non triangular but more rhomboid shape). As the exploration progresses, the white line of tissue going lingual from the MB1 leads us to the location of the MB2 which is mesial to the line connecting the MB1 and the Palatal canal.

The above case demonstrates how understanding white lines and the dentin map with the knowledge of how the MB2 courses back into the MB root can help the dentist find these elusive canals.

Tomorrow further discussion will be given to the use of the microscope for canal localization and access refinement.

Until then keep your eyes open and your scope light on.....

Glenn

Endo and the Operating microscope - Part 2

Mon, 26 Nov 2007 21:53:13 -0800

In yesterdays Blog entry, the topic of the microscope in the literature was broached (pun intended). There is a growing body of evidence in the literature on the role of the microscope in the discipline of endodontics. Much of the concentration of the literature has been focussed on the role of the higher levels of magnification for early access into the pulp. The published material has focussed on ability to discover 4th canals in molars, particularly the MB2 in maxillary first molars which are one of the most likely teeth to fail after initial endodontic therapy. Often the inability to locate the 4th canal is a cause for failure through untreated pulpal anatomy.   Located below you will find more references to the role of the microscope in endodontics.

In all of the studies posted except for the last one by Sempira the findings were positive for the microscope as an advantageous part of the armamentarium for endodontics.

The next entries in the coming days will deal specifically with cases where the microscope helped provide an answer to a difficult clinical case.

Until then, happy scoping.

Glenn

ENDO and the Operating mIcroscope - show me the LIT!

Sun, 25 Nov 2007 12:36:12 -0800

Many people have asked during what parts of the endodontic treatment does the operating microscope help with. I guess the simple answer is all of them, particularly if you look at the value of the operating microscope for ergonomics, for its ease of documenting in video and still digital media and finally for the ability to show patients, staff and colleagues any portion of the entire procedure.

In this first part of looking at the benefit of the microscope for endo, I will attempt to provide some literature that extols the power of the microscope for endo. Much of the literature has focussed on the role of the scope for finding more pulpal anatomy (extra canals) compared to no magnification or low power loupes.   One has to only look at the tremendous teaching cases of Dr. John Khademi who shows consistently not four canals in a molar but 5 or even 6 canals. The complex pulpal anatomy particularly in posterior teeth (molars and premolars) is difficult to discover without the tremendous illumination and magnification that is the operating microscope. One of the most compelling posts for this can be read on DentalTown (DT) and is entitled “ Hank''s definitive guide to the MB2 and beyond.” You must register on DT for free to be able to read it but if you want to discover some incredible images on what can only be seen with the operating microscope then you owe it to yourself to read the thread from beginning to end. That one thread will make you better in endodontics. I guarantee it. Just to wet your appetite I have copied a couple of the images from the thread with special thanks to Dr. Khademi. The thread is located at:

http://www.docere.com/MessageBoard/thread.aspx?s=2&f=113&t=64845&v=1

The literature that exists on the power of the microscope I will provide today and tomorrow in slides from my lectures. You can see that there is a fair amount of published literature demonstrating the microscope offers a tremendous amount of value to locating extra canals and reduces the reliability on tactile means for locating these canals. Visually the dentin map provides keys to where the canals are and this becomes much more obvious with higher powers of magnification.

These studies form part 1 of the literature supporting the use of the microscope in endodontics. The endodontic post graduate programs in North America all have microscopes and students are strongly encouraged to become proficient in the usage of the microscope during their 2-3 years in the program. Most new graduates who open new practices quickly get in contact with the microscope representative in their area to order the necessary microscopes to equip their office. They know that part of the secret to obtaining the outstanding results they can provide lies in the vision that the operating microscope gives them.  Tune in tomorrow for part two of the literature and the microscope in endodontics as we explore the original reason for the implementation of this technology into dentistry.

Pair of Cracks - a predictor of interproximal decay

Fri, 23 Nov 2007 11:19:35 -0800

If you have never read Dr. David Clarks article on cracked teeth you owe it to yourself to get a copy of the article, read it, digest it, read it again. Its that important an article for those of us who use the operating microscope. I will occasionally cover a single type of cracks that David talks about in his landmark article. Today is one of those days.  David was the founder of AMED and his enthusiasm and initiative were the driving force for the organization that acts as the primary annual gathering for us “microscope junkies” from all over the world. David and I met for the first time at his house in 2001 in July and the first AMED meeting was in 2002. Here are some of those first photos in the early formulative years before AMED (www.microscopedentistry.com) was formed. We went fishing and to his office.
David was the first person to use the ceiling track from Global to service two rooms with one scope. A cool idea for sure that can be used in situations where there is pass through and narrow rooms.

In any event, David and I formed a friendship in those early days and I have had the opportunity to see him rise in status as a microscope clinician and a fantastic speaker. Davids concepts on New Patient Exams, porcelain, resin restorations, unique matrices, photography, cracked teeth and ultrasonics with the scope have all furthered the cause. If you have not read his landmark article it can be downloaded from the publications section of his website:

www.lifetimedentistry.net where you can find alot of great articles for microscope users to download.
 Here is his article on cracked teeth

http://www.lifetimedentistry.net/article-clark-jerd2003.pdf

So in this article David talks about high risk fractures that are visible in the enamel that may have relevance to structural dentin cracks that are the precursors to either cuspal fracture (oblique) or those which run mesial to distal and can cause pulpal or complete vertical fractures (vertical).

David mentions “paired cracks” as being cracks to be concerned with, and in my experience these are located on the marginal ridges and often run right into the interproximal decay that may not be radiographically evident but are clinically significant and generally when the crack is present into the dentin. David talks about the value of Methylene Blue Dye (MBD) for helping locate cracks and it works well on these cracks.

So in this case from yesterday, a patient was having three old amalgam restorations replaced and there was ALOT of decay under these moderate old amalgams. Note on the first molar the mesial marginal ridge the paired cracks in the enamel. One of them is larger and houses debris and this crack ran along the ML cusp (it was the more significant of the two) and these cracks actually were the Buccal and Lingual extents of the decay on this tooth. Here are the photos of the buildups for thes teeth and we plan to do a full coverage restoration for this cracked tooth.

In the below photos you see the MBD on the tooth Blue and viewed at low and high magnifications.

The restoration was removed (upper right) and then the decay on the interproximal was seen and the mesial marginal ridge removed.

The preps are completed below and ready for the direct resins.

The completed restorations are below.

Many future posts on this blog will deal with the fascinating topic of cracked teeth so keep an eye out for more in the future.

Have a great weekend.

Glenn

Look What I found!

Thu, 22 Nov 2007 03:06:31 -0800

When I started using the operating microscope, it quickly became evident that the tremendous improvement in visual acuity through both magnification and illumination allowed for much earlier diagnosis of decay. I still will bring over the diagnodent to help me quantify an occlusal lesion in terms of size and know whether it is possible to treat it without the dreaded needle. The “shadows” that the microscope illuminates is impressive. Far earlier than depending on cavitation and detection of an occlusal lesion with the tactile means of an explorer, the microscope allows for early diagnosis and more conservative preparations and restorations to be completed.

In this case at 2.1X magnification not much could be determined clinically.

Now when the magnification was increased to 8X, there was a hint of a shadow visible but on the right hand side the gray color shining through the enamel becomes much more obvious.

In the mesial pit of this upper first molar was significant decay as visible in the following photographs and the final depth of the preparation was 4 mm in this case. There was no cavitation yet on this tooth, and the fluoride in the toothpastes is leaving us with a much more difficult time in diagnosing through tactile means these decayed teeth.

In the above photos you can see with the conservative small fissureotomy burs that the extent of the decay becomes visible early on when one reaches the DEJ border.

The Conservative OL preparation on the right is restored with blow flowable and hybrid resin in a direct fashion using Gradia. The final conservative preparation on this 13 year old patient provides hope that the tooth will last a long time before replacement of this restoration becomes a necessity.

Til next time, happy scoping, and let the microscope change your view of the profession!

Glenn

Using the full range of Magnifications

Wed, 21 Nov 2007 02:37:58 -0800

The answer to which magnification I use the most is ALL of them. To be honest when I look at the range of magnifications that I have, I break the 6 steps down to 3 groups. There is a LOW magnification range of 2.1 and 3.2X power. These are very useful magnifications for things like placing rubber dam, providing anesthetic, evaluating line of draw, looking at a smile from commissure to commissure, looking at a whole quadrant at once, placing orthodontic brackets, gross reduction of tooth structure in crown preps and new patient exams (zooming in to an area as need be). This low range of magnification is where most new users will find greatest comfort as the depth of field is largest and in the beginning of the learning curve it is too difficult to commonly use the higher magnification range for anything more than observation. Keep at it though because with time you will master using all the magnification range for clinical work.

The two middle magnifications are the 5.1 and 8X power. These are the workhorses for many clinicians where endodontic access, instrumentation, and obturation are done. These turret settings are .8 and 1.25 and will allow you to comfortably prep restorations both for resins and fixed prosthodontics with enough depth of field to not be out of focus all the time. I use these settings to work on one tooth with enough magnification for the bulk of my work. My favorite setting for most preparations is 1.25X and I take alot of my photographs of anterior and premolar teeth and this setting. The molars need a little less power to get a single tooth completely in the frame. These magnifications are where the majority of clinical decisions are made.
 The highest levels of magnification are used for clinical checks. The 12.8X mag is useful for margin refinement in prosthodontics, determination of cracks, searching for MB2, MB3 , DB2 etc anatomy. This is in my hands the maximum setting that is useful for clinical dentistry. The depth of field drops significantly from this setting to the highest level. The 2X turret setting requires more light to see properly and again although this setting is impressive for photos, it is more difficult to get sharp, well exposed photos at this setting without flash. The 19.2X mag which is the 3X turret setting is useful for spot checks when looking for separated files (of course these are always referral cases and not occurring in your office!). The also can be useful to see if a crown fits in an area to search for decay in certain locations and to help in endodontics. These high magnifications significantly slow down the speeds of clinical work due to their limited depth of field.

So there you have it, the microscopes for dentistry have various steps between 2x -20X magnification and they are all useful. Once you become capable of using all of the powers then you will find yourself comfortably shifting between the various magnifications depending on the amount of visual information you require and using ALL of them!

Yours for better clinical microscopic dentistry- Glenn.

OLD EYES, young eyes, any eyes.

Mon, 19 Nov 2007 12:47:17 -0800

The microscope offers all users regardless of their eyesight tremendous improvements in visual acuity through the increase in visual information it provides by magnification and illumination.
Dr. Assad Mora at an early edition of AMED provided us with food for thought by the following table. The table shows us the tremendous improvement in visual acuity that is possible when we start to increase magnification compared to the naked eye and low level loupes. This amount of visual information is both alarming and exhilarating. In the beginning the dentist has too take extra time to complete the procedures at higher magnifications simply because of all this extra visual information. The dentist finds extra canals in endo, tissue in the canals at the end of instrumentation, cracks in a tooth that they didn't see at the lower magnifications, decay still left behind in the corners of a preparation or on an adjacent tooth, the margins look still rough or there is calculus or decay still left behind. The ability to see more means extra time needed initially to improve the preps , finish the endo or complete the restoration. With time you become faster though than you did before simply because there are no gray areas in the decision making process. You don’t have to check with tactile means to see if the crown fits, you rely more on visual methods to assess your clinical treatment outcomes.

When you look at visual acuity in these realms it is easy to see why dental schools at University of British Columbia, University of Washington, University of Maryland, and others are starting to incorporate the magnification possible with the operating microscope into undergrad studies for both endodontics and regular procedures. Why? Well the advantages of improved treatment outcomes, improved communication with patients, staff and colleagues, improvements in ergonomics and improvements in documentation can be appreciated by young and old eyes alike!!

Table of Visual Information at various magnifications.

R