GLIDEPATH ESTABLISHMENT

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Before beginning treatment of your next patient, review toothatlas.com for all the teeth that are similar to the one you will treat. Also, look at page 129 of Michael Cohen’s popular interdisciplinary text which indicates the number and frequency of canals for the tooth you are planning to treat.5 Armed with these 2 pieces of information, you will be better prepared for the root canal system anatomy that Mother Nature has in store for you. This preparation is essential for beginners and seasoned masters alike because it is as if you had an endodontic GPS. All you have to do is follow Mother Nature’s directions and rules.

Glidepath Implementation Skill No. 1—Glidepath Mechanics: “How Do I Produce Desired and Consistent Technical Outcomes?” (Figures 1a to 1e)
• Vision
• Finishing Checklist
• Quality Control
• The Intentional Mind

Vision: Start with the Answer
1. Design and prepare a successful access cavity.6 In anterior teeth, triangle No. 1 (mostly comprised of enamel) and triangle No. 2 (mostly comprised of dentin) must be removed. In posterior teeth, internal dentinal triangles must be removed using Gates Glidden burs, X gates (DENTSPLY Tulsa Dental Specialities), or ultrasonics.
2. Magnification and illumination are essential. The microscope allows superior ability to see while maintaining good and healthy posture.7
3. Immediately after straight-line access, wash the chamber using water; preferably by using the Stropko Irrigator. Grade your access cavity for smooth walls finished with a tapered diamond and orifice that allow full freedom to “follow.” There should be no impeding enamel or dentinal triangles. Straight-line access is the first step toward successful Glidepath preparation and subsequent successful cleaning, shaping, and obturation. Thoroughly flush chamber with sodium hypochlorite (or preferably with Chlor-XTRA [Vista Dental Products] which has 4 times the capacity to digest both necrotic and detached pulpal tissue) and agitate solutions using EndoActivator (DENTSPLY Tulsa Dental Specialties) for one to 5 minutes, depending on the amount of pulpal remnants in the access cavity. Be patient here, making certain that your access is finished before proceeding. Many dentists are already thinking about “getting the length of tooth.” Many times, you never get it. You see you never know if it is the right time to “follow.” It has to be discovered. You are setting the tone for “following” the canal to the RT. This is a time for exploration, discovery, inquiry, wonder, enjoying the moment, fascination, learning local knowledge and “booby traps,” and expecting the unexpected.8 After all, Mother Nature does not make straight-lines and she does not make 2 the same.9,10 If you understand this, you will never be surprised. Instead, you will surrender to the needed passive, gentle, and time-does-not-matter skills. The only thing that matters is that you “follow” to the end of the canal. (If you did not do as suggested earlier, this is a good time to read/review “The Endodontic Glidepath: ‘Secret to Rotary Safety,'” September, 2010; available at the Web site dentistrytoday.com.)
4. Imagine the final obturation. Remember to start with the answer: 3, 2, 1. Start with the end in mind. Then, imagine seeing the No. 10 endodontic file at the RT. Imagine seeing it “following” there.
5. You finally have designed an unimpeded access and you can look directly into the orifice (Figures 2a to 2t). You are ready to follow. I start with file that I think will follow easily, which is smaller than the one that may follow. It is better to error with a file that is too narrow than with one that is too wide; this is because if the wider file is approximately the same diameter as the file, it will plow attached, detached, or necrotic pulp and calcifications ahead of it and produce an early block. Again, this is the time to tap into your attitude and state of mind of slow down. If you don’t, and you make a mistake, you may need all day. Irrigate with Chlor-XTRA or sodium hypochlorite. Smoothly curve the last 5 mms of the first file. Finesse the file tip into the orifice. Follow the file as far as it can easily go and absolutely slow down before maximum resistance and carve your way out using the envelope of motion in order to remove potential restrictive dentin. Repeat follow/envelope/follow/envelope until you reach the RT. If the envelope does not allow the file to progress, remove again before maximum resistance, recurve the file and/or go to the narrow file and repeat follow/envelope plan to RT. If the file easily follows to the RT, follow along for the ride. (The only exception would be if the canal had significant necrotic debris present, or if the tooth had been left open for drainage and the canal was full of bacteria and/or food.) If the file were to easily follow, that is exactly what you want. Then, do a smoothing motion (smoothies) until the No. 10 file is super loose. You are now ready for rotary. Sometimes a sufficient Glidepath for rotary already exists in the root canal. If the No. 10 file literally falls to the RT, then Mother Nature has done you a favor. She has given you a canal that is already large and smooth enough for safe rotary; and, generally speaking, the walls are also sufficiently smooth enough for rotary or reciprocation. However, if you prefer a wider Glidepath, then proceed with a No. 15 file using the balance motion or used better progressively sized Series 29 manual files Nos. 1 to 3 (DENTSPLY Tulsa Dental Specialties). As I described in the second Glidepath article in this series (“Manual Versus Mechanical Endodontic Glidepath,” January 2011; available at dentistrytoday.com), mechanical techniques, such as PathFiles (DENTSPLY Tulsa Dental Specialties) are also useful when a wider Glidepath is preferred for rotary safety. A second technique is to navigate No. 10 file just short of maximum resistance and then “brush” away restrictive dentin with ProTaper Shaper (DENTSPLY Tulsa Dental Specialties) files S1 and S2 short of No. 10 file depth, “follow” again with No. 10 file and expect to “follow” deeper. Repeat as necessary.
6. Irrigate thoroughly. Again the “Glidepath Finishing Checklist” is simple but the critical distinction before rotary.
7. For me, the next step is to manually follow into the Glidepath with ProTaper S1 and manually turn and carve clockwise.11 My hands are acting as the handpiece. Typically, I will make 2 to 4 rotations, and because of the exceptional ProTaper efficiency, and the progressive taper, the S1 naturally follows and carves away restrictive dentin in preparation to the finishers whose sole job is to connect the preparation outline dots from RT to orifice. Once S1 is 2 rubber stoppers away from the RT, then I know I am safe and I can then mechanically, and in full; rotary float, follow, and brush with purple S1 safely, while staying in control of the shaping. While other rotary systems may require a wider Glidepath than a super loose No. 10 file, the thought process and technique of manual rotary followed by mechanical rotary holds true. It should be noted that a current and becoming highly popular Glidepath sequence is first a super loose No. 10 file followed by the 3 PathFiles. The width of the Glidepath is safer yet.
Finishing Checklist: “You don’t get what you want in endodontics, you get what you measure”—Be sure to radiographically or digitally verify your “first instrument to the RT” before proceeding with Glidepath preparation (Figure 1d). Then and only then proceed by preparing a reproducible and verifiable Glidepath by making dozens of short vertical amplitude strokes at the RT position then increasing the stroke amplitude until a super loose No. 10 endodontic file can easily, effortlessly, and repeatedly make longer and longer smoothing strokes until the stroke’s amplitude reaches mid root.