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Barry L. Musikant, D.M.D., F.A.S.D.A.
Adding the Third Dimension to Endodontic Education
Barry Musikant

Barry Musikant

A COMPLAINT that comes through loud and clear from many dentists on Dentaltown.com is their frustration at not knowing what to look for when they create their molar access.  This shortcoming is most noticeably apparent when canals are missed.  That so many dentists on Dentaltown are aware of this deficiency is a testament to those who have emphasized on the site what is being missed.  Poor access and missed canals are to my mind consequences of inadequate teaching in the dental schools, but it is never too late to rectify these deficiencies.
    Access, the initial key to successful endodontics, can be taught with great clarity by first emphasizing exactly what dentists should be looking for when they create access and extend the depth of their preparations apically.  They must first be aware of both the roof and the floor of the pulp chamber.  I have seen many dentists work a reamer or file through a hole in the roof down a canal believing that the hole in the roof is an orifice.  I have also seen dentists perforate through the floor of the chamber believing that they have yet to reach the roof of the pulp chamber.
    One good way to set some initial depth limits is to use the PulpOut® bur, a high-speed round bur with a 7 mm stop on it that prevents perforation through the floor while gaining access to the middle anatomy of the pulp chamber.  In addition to the PulpOut bur, a barrel diamond with a non-cutting tip is used to extend the access laterally.  By using these two access burs on all teeth other than those severely worn down, an accurate initial entry is quickly and effectively made.
    Now that the dentist is within the confines of the pulp chamber, he or she must probe for the tissue inclusions that may be present.  Certainly, in a maxillary molar MB, DB, and P canals are most likely to be present and are usually confirmed by a routine periapical x-ray.  In addition, the dentist must be on the lookout for MB2s and possibly MB3s, DB2s, and second palatal canals.  Many of these secondary or tertiary canals are common with the primary canals, but we may not be aware of their presence until later in the shaping process.
    It is easy to say, “Be on the lookout,” but what exactly does that mean, particularly in the presence of secondary dentinal deposits laid down over time?  It means that we have to have the vision and tools to remove these secondary dentinal deposits to uncover tissue that at an earlier stage of life was quite apparent, but today is buried under these secondary deposits.  We must also be aware that many of these secondary canals are secondary only because of these deposits.  Many were once single-tissue inclusions before secondary dentinal deposits partially occluded them.
    We believe that it is important to remove the coronal isthmus between these canals because the isthmus contains tissue, and where tissue exists bacteria can breed.  The isthmus may be removed with a Peeso-like reamer and the area cleansed via ultrasonics and NaOCl irrigation.  Little is achieved by protecting an infinitesimally small amount of dentin at the expense of leaving tissue intact for the sake of leaving the tooth marginally stronger.  This point should be driven home by the fact that we are essentially removing dentin that was laid down after the tooth was fully formed in a person’s twenties.  To make the endodontic procedures safer and more predictable, we are removing the distrophic additions laid down in the subsequent decades of life.
    From a practical point of view, we want to emphasize tools that will allow the dentist to remove lateral and apical dentin safely while probing for all the tissue inclusions that may be present.  In our opinion, the most important tool is the microscope.  Its combination of illumination and magnification trumps any other tools available.  The microscope allows the dentist to use fine long-shank surgical steel round burs—like the Munce burs—and ultrasonics to uncover these buried tissue inclusions.  Now as an endodontist, it is fine for me to say use a microscope, but in reality most dentists will never appreciate that statement unless they take the time to look under the scope.  They can see enlarged images at a lecture to gain some appreciation of the microscope’s benefit, but a two-dimensional depiction of the depth created during access does not do justice to what is actually seen under a microscope.  One way to rectify this limitation is to give every dentist attending an endodontic lecture a microscope, an open tooth, and a set of probing instruments.  This is possible in a hands-on course, but the number of dentists able to take such a course at any one time is limited by the extensive requirements.  Another way for dentists to appreciate what they could be seeing under a microscope is to present to them in a lecture forum a series of three-dimensional images that come very close to duplicating what they would be seeing if they were actually looking under a microscope at the time.  The inclusion of the third dimension is so dramatic that the benefits of the binocular microscope become undeniable.
    Very few dentists have ever seen these 3-D images.  Documenting a highly calcified pulp chamber from initial access to discovering extensive tissue inclusions that open to the apices gives the dentist an appreciation of the control he or she could have with the proper tools used in conjunction with the microscope.  With the technological innovation of 3-D as an effective teaching mechanism, we can give dentists a more defined set of standards than they have had until now.  Once dentists are able to build up a series of ideal images in their minds, they will be able to duplicate these standards.  The only reason dentists may not know what they do not know is past inadequate teaching.  With the advent of 3-D microscopic projections, the dearth of true excellent imagery is eliminated.  After that it is practice, practice, practice on extracted teeth, ideally under the microscope with a previously taught well-defined endpoint in mind.
    With the tools we use today to teach our endodontic courses, there is no reason why any motivated dentist wanting to excel in endodontics cannot expand his or her skills.  We believe that we are pioneers in this form of education.  We expect 3-D education to expand dramatically in the future, but we are excited to be the first to offer the tools to make you the best you can be.
    Illustrating this article are some examples of images that can be printed or projected onto a screen. When you look at these images, you will see 3-D only if you have the red and blue glasses that you may be familiar with from years ago. Since most of you don’t have these glasses, we are more than happy to send you a free pair if you send us your address.  Please request the glasses by e-mailing Olga Fernandes at ofernandes@edsdental.com.  When you use the glasses, make sure that the blue filter is placed over the right eye.
    When you get the glasses, I hope you enjoy looking at these images as much as we enjoyed creating them.  Going forward, we plan to base more and more of our education on 3-D images.  It is an exciting time!
    If you are interested in taking one of our two-day hands-on workshops or would like to participate in a forum limited to lectures but including the 3-D presentations, please contact us at (212) 582-8161.

September - October 2007
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Essential Dental Seminars
To speed up access without perforation, use the PulpOut™ Bur.


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© Copyright 2006 by Musikant, Deutsch, Kase, Dukoff, Bui, Lipner, & Kim. All rights reserved.