86 ENDODONTICS The Endodontic Glidepath: “Se cret to Ro ta ry Safe ty” INTRODUCTION is to serve as a reference guide for endodon - WHAT IS A GLIDEPATH? You will do it 5,000 times in your career. tic Glidepath preparation and answer the The endodontic Glidepath is a smooth radic - Give or take a few… following questions: What is it? Why is it ular tunnel from canal orifice to physiologic The ADA estimates that most dentists important? How do you predictably prepare terminus (foraminal constriction). Its mini - treat an average of 2 endodontic teeth per the Glidepath? mal size should be a “super loose No. 10” week. If we assume there are at least 2 canals endondontic file. The Glidepath must be dis - per tooth, 47 treatment weeks per year for STARTING WITH THE ANSWER covered if already present in the endodontic 25 years, then most dentists will attempt The purpose of endodontics is to prevent anatomy or prepared if it is not present. The John D. West, approximately 5,000 Glidepaths in their or heal lesions of endodontic origin. 1 In Glidepath can be short or long, narrow or DDS, MSD career: 2 root canals per week x 2 canals per order to achieve this purpose, the root wide, essentially straight or curved (Figure 2). tooth x 47 weeks x 25 years = approximately canal system must be successfully obturat - 5,000 Glidepath attempts. ed. In order to be obturated, the root canal WHY IS THE ENDODONTIC GLIDEPATH The amazing fact is that the subject of system has to be successfully 3-dimension - IMPORTANT? Glidepath has no formal training in the ally (3-D) cleaned and rotary shaped. In First, without the endodontic Glidepath, the endodontic curricula of most dental order to be 3-D cleaned and rotary shaped, rationale of endodontics cannot be achieved. schools. In fact, a PubMed Central search of a Glidepath has to be successfully pre - The rationale states that “any endodontically Glidepath and endodontics reveals 300 ref - pared (Figure 1). And so the Glidepath is diseased tooth can be predictably saved if the erences. However, none of them actually the answer. It is the starting point of radic - root canal system can be nonsurgically or describe how to prepare a Glidepath. Most of ular preparations. Without it, cleaning surgically sealed, the tooth is periodontally the references say something like, “Of and shaping become unpredictable or sound or can be made so, and the tooth is course you must first make a Glidepath.” impossible because there is no guide for restorable.” 1 A nonsurgical seal requires first That’s all. And so the purpose of this article endodontic mechanics. the creation of a radicular path that can be cleaned of viable and nonviable bacteria, vital 1. What size hand file do you prefer for your Glide Path? (Choose one) and nonvital pulp tissue, A. Size #10________ biofilm, and smear layer; B. Size #15________ C. Size #20________ then shaped to a continu - D. Larger_________ ously tapering funnel that 2. Do you use straight manual files or do you curve them? (Choose one) can be predictably and eas - A. Straight______ ily obturated. B. Curved_______ Second, the Glidepath 3. Do you “go to length immediately” if you can or do you “do early coronal enlargement” is necessary for quality first? control. Sustainable excel - A. Immediately if I can_____ B. Early coronal enlargement______ lent endodontic obtura - Figure 1. Glidepath is key to Rotary Shaping. 4. When making the Glide Path, what is your preferred irrigation solution? (Choose one) tions are not possible Pretreatment image (left) shows apparent apical calci - without it. fication. Post-treatment image (right) reveals proper A. Sodium hypochlorite_______ B. EDTA_______ apical shaping and obuturation made possible by suc - C. Viscous chelator such as ProLube, Glide, or RC Prep_______ cessful Glidepath preparation. D. Combination of the above_______ HOW DOES THE 5. How do you determine your Glide Path length? (Choose one) DENTIST PREDICTABLY PRE - A. Apex locator_______ B. Radiographic terminus______ PARE THE GLIDEPATH? C. Both of the above________ In order to answer this 6. When making the Glide Path, what hand motion(s) do you use? i.e.: “watch/wind,” question, I first surveyed “push/pull,” or other. the American Association of Endodontists (AAE) 7. When blocked, what do you do next? and reported my findings at the AAE annual scien - 8. When you first notice a shelf starting, what do you do next? tific meeting in San Diego Figure 2. 2 Glidepaths occur in multiple widths, lengths, on April 16, 2010. The and curvatures. They can be long or short, wide or nar - title of my presentation row, curved or more curved. Root canal system anato - 9. If you were to design the ideal Glide Path file(S), what would you want as your most desired features or characteristics? Please be specific. (Optional) was “The Magic of Mas- my is often tortuous and in multiple planes not observed in 2-dimensional images. Glidepaths must tering the Glidepath: ultimately “follow” and replicate the original canal path What Every Endodontist Figure 3. in order to preserve the position of nature’s portal of Sample of Glidepath survey letter to endodontists. Answers to Nos. continued on page 88 exit locations. 1 through 6 are presented in Figures 4 to 9. DENTISTRYTODAY.COM ¥ SEPTEMBER 2010 88 ENDODONTICS The Endodontic Glidepath... Hand File Size Preference Straight or Curved File Preference Go to Length Immediately or Early continued from page 86 Coronal Enlargement 3% Size No. 10 Should Know .” I asked the following 6 Straight Immediately Size No. 15 questions (Figure 3). The survey 16% Curved Early Coronal 18% Size No. 20 Enlargement results speak for themselves. Larger 43% 1. What size hand file do you pre - 45% fer for your Glidepath (Figure 4)? 2. Do you use straight manual files 57% or do you curve them (Figure 5)? 84% 34% 3. Do you “go to length immedi - ately” or do you do “early coronal enlargement” (Figure 6)? Figure 4. Figure 5. Figure 6. 4. When making the Glidepath, Hand File Size Preference. More Straight or Curved File Preference. Go to Length Immediately or Early than one-half of endodontists prefer a rotary The only valid time to use a straight file is slid - Coronal Enlargement. Slightly more endodon - what is your preferred irrigating solu - Glidepath file size No. 15 or larger. As ing into the orifice where the angle of inci - tists prefer early coronal enlargement, primarily tion (Figure 7)? described in this article, the author prefers, dence is greater than the angle of access. due to the presence of restrictive dentin which 5. How do you determine your instead, a “super loose No. 10.” restricts finesse and mastery of the first Glidepath length (Figure 8)? Glidepath file. 6. When making the Glidepath, Irrigation Solution Preference Determination of Hand Motion Preference what hand motion do you use (ie, Glidepath Length Sodium Watch/Wind “watch/wind,” “push/pull,” or other) Hypochorite Apex Locator Push/Pull (Figure 9)? EDTA Radiographic 9% Both Viscous Terminus 32% Chelator 32% Both Other GLIDEPATH TECHNIQUE Combination There are 4 skills that you need to know 39% 23% in order to produce consistent Glide- 55% 58% paths for safe rotary. First, find the canal. When beginning an endodontic 6% 13% 10% procedure, it is useful to know the num - 23% ber of canals typical to a particular 1 tooth. It is also useful to know the typ - Figure 7. Figure 8. Figure 9. Irrigation Solution Preference. Determination of Glidepath Length. Hand Motion Preference. Most ical anatomic variations of the specific Sodium hypochlorite and a viscous chelator (or The apex locator, or a combination of apex endodontists prefer “watch/wind.” Only 9% tooth you have scheduled to treat (ehu - a combination of the 2) enable digestion of locator and radiographic terminus, is the clini - chose “other.” This article describes the critical man.com/products/3d-tooth-atlas-6). necrotic pulp and the ability to emulsify vital cian’s choice. Canal length accuracy is excel - distinctions of the manual motions of pulp. lent when both methods of length determina - Glidepath preparation. These 4 motions make When reviewing ToothAtlas teeth, the tion validate each other. The important thing to endodontic files efficient when the dentist first realization is the typical root canal remember is that the length is dynamic and learns how, when, and why to use what system anatomy of a specific tooth is not becomes shorter, especially in the early stages motion. Glidepath demands that the dentist of rotary shaping, due to canal shortening. “thinks” and is “deeply present,” resisting all typical at all. None are the same and that distractions. is the lesson: always expect the unexpect - ed ; no 2 root canal systems are the out magnification and illumination Third, understand the 4 possible words, the file curvature and the canal same—root canal systems are literally (Figure 10). reasons (or a combination of these 4 curvature do not mimic each other. like “banners in the breeze.” They are Second, “ follow ” the canal to its radi - reasons) why you may not be able to Solution : The key here is randomization. complicated and curved, their canal ographic terminus (RT). While the RT is easily follow to the RT (Figure 12). 3,4 Rather than think “the canal goes left,” walls vary from smooth to rough, from always some distance past the physio - 1. The canal is clogged or seemingly or “the canal is coming toward me,” wide to narrow, or from patent to logic terminus, the RT is the best default blocked by dense collagen or necrotic instead simply allow the file to “follow” clogged with pulp, necrotic debris, or or home base position (Figure 11).