The Endodontic Triad: ‘Dead or Alive?’

INTRODUCTION
“Change is the only constant.”

The Greek philosopher Heraclitus is credited for speaking one of nature’s absolute rules about time and change. However, perhaps because events and things like inventions were slow to change 2,500 years ago, Heraclitus did not mention the rate of change. In April 2021, the rate of change is becoming exponential. In fact, we are at the knee of the exponential technological curve, and the rate of change is continuously increasing. In this article, I have chosen to link the phenomenon of endodontic change from the past, present, and future, inviting the reader to ponder the question of The Endodontic Triad: “Dead or Alive?” My goal is to see the Triad (Clean, Shape, Pack) through the eyes of change, which will hopefully invigorate each reader to embrace new possibilities for becoming a better endodontic clinician.

Context
This is an article by a clinician, for clinicians, about clinicians.

Endodontics is about clinician decisions. My aspiration in this writing is that we all make the best decisions toward improving our performance and increasing our patients’ endodontic predictability. My assertion is The Endodontic Triad is Alive!

ENDODONTIC CAPACITY FOR SUCCESS: THE RATIONALE FOR ENDODONTICS
Endodontics is an extension of restorative dentistry into the radicular space. It is nature that sets the rules about our success.

Nature promises that if a disease, such as endo­dontic disease, is eliminated, then the symptoms of the disease simultaneously cease. Therefore, endodontics has a 100% capacity for healing if the root canal system is rendered innocuous and the tooth is periodontally sound and restorable.¹ But every dentist knows we experience our own individual success rates, and they are 100% − X.

What is X? It is the clinician and the host: (1) our knowledge of what to do, (2) our ability to do it, and (3) our willingness to do it matched against the host response. Can endodontic technology bring the big “X” in 100% − X to become a much smaller “x,” ie, 100% − x? It can, and it will. However, there are biologic and percentage success comparison challenges in producing the new, smaller “x.”

Professor Shimon Friedman, an authority on endodontic success/failure studies, suggested 3 biologic culprits currently preventing 100% predictability: (1) inaccessible niches with infected tissue, (2) the very resilience of bacterial biofilms, and (3) bacterial films outside the radicular space.²

Friedman further reports that it is difficult to measure and to compare success from study to study and from clinician to clinician. He notes that reported success rates have ranged from 29% to 100% because of variations in research methodologies (study cohort, follow-up, outcome assessment, data analysis). This includes the very definition of “success,” noted as no radiographic or clinical signs of disease; no symptoms, even in the presence of disease; and tooth retention, even in the presence of disease and symptoms.²

Despite these challenges, the goal of closing the gap between the big X and the small x is endodontics’ “clear and present” opportunity. Endodontics does not shrink from this responsibility. It welcomes it. Bring on the “aliveness” part of The Endodontic Triad: “Dead or Alive?”

Figure 1. The Past. (a) Image from Gary Grey’s 1973 Boston University thesis, demonstrating a thoroughly debrided horizontal section of an extracted tooth. Only hand files, Gates Gliddens, and NaOCl were available in those days. (b) Two endodontically treated teeth in a row by Professor Herbert Schilder in the 1960s. Note the radicular shapes were appropriate for their roots (minimally invasive endodontics by today’s standards) and the solid obturation with multiple portals of exit visibly filled. (c) Standing on the shoulders of giants. I taught my mentor, Schilder, the use and value of the microscope (circa 1993). (d) In the 1970s, Schilder used to refer to the then-endodontic attempts at Clean, Shape, Pack “gadgets” as “complicated solutions to nonexistent problems.” He meant that if the endodontic anatomy is eliminated using a compulsive attitude to do so, a capacity for 100% success is available to all dentists. My contracted “Rube Goldberg” cartoon from 1985 reflects this same insight.

THE PAST
Endodontics became a dental specialty in 1964. At its very beginning, endodontics’ idea of the Triad was revelatory, as was the deep commitment to it. Even in the age before NiTi, microscopes, apex locators, and digital imaging, careful and vigilant attention to technical detail produced verifiable success.^3,4 It has been said many times before that we stand on the shoulders of giants, and now future giants stand on our shoulders today (Figure 1).

THE PRESENT
I first chose to write this article for personal, curious, and selfish reasons. I wondered if I am using the best tools, techniques, and technologies that endodontics has to offer. Am I stuck in my ways? Am I missing a transformational endodontic moment, or maybe I am missing a better way to find orifi or something simple like that? A better way to see if I’m missing anything—and, if so, what I am missing—is to seek out a few of my respected endodontist peers who (1) I know perform the Endodontic Triad, or parts of it, differently than me; (2) have extremely successful practices and probably are at chairside as of this writing; (3) are continually striving to learn to be their best and understand that this adventure into optimum endo­dontic predictability is both a journey and a destination; (4) walk the talk; and (5) are not only lifetime students but also lifetime teachers.

Next, I must define my first 3 survey questions about Clean, Shape, and Pack (CSP).^5,6 I realize different clinicians use different terms to describe nonsurgical endodontic treatment. CSP is the term that I have used to describe the Triad for over 4 decades. For example, in our office, we say, “Schedule Mary for CSP #14.” It is easy to say and easy to note on the daily schedule. It has always described my exact and purposeful process for intended patient outcomes—namely, eliminating the root canal system in order to cure or prevent a lesion of endodontic origin.^7-11

Please substitute any words you want to describe the Triad: Clean, Shape, Pack. Feel free to even reverse the order. Possible Triad words you are more than welcome to substitute are:

Clean—debride organic and nonorganic root canal system contents, disinfect (there are over 100 trillion microbes in the human body; it is no surprise a few may stray into the pulp space where they are not welcome)

Shape—preparation to facilitate cleaning and cone­fit for obturation control, instrument, verify or ensure patent tunnel for fluid flow

Pack—fill, obturate, thermoplastic seal, 3D seal, endo­dontic seal, cork

Figure 2. The Present. Pretreatment and post-treatment radiographic expressions of the Endodontic Triad submitted by 10 respected endodontists: (a) Dr. George Bruder, (b) Dr. L. Stephen Buchanan, (c) Dr. Gary Glassman, (d) Dr. Manor Haas, (e) Dr. John Khademi, (f) Dr. Charles Maupin, (g) Dr. Tom McClammy, (h) Dr. Blake McCray, (i) Dr. Terry Pannkuk, and (j) Dr. Reid Pullen.

The Respected Clinician Clean, Shape, Pack, and Sealer Survey
Agreeing to my definitions, I chose to survey 10 respected endodontists who have proofread my condensing of their answers and have selected pre- and post-treatment images that they believe radiographically represent their trenchant visual expression of the Endodontic Triad (Figure 2). Below, in alphabetical order, are their answers to my survey. Their techniques or armamentaria were copied and pasted from the survey, and where a quotable opinion was offered, it appears in quotes.

1. Dr. George Bruder

• Clean: “SyAct has moved toward a novel methodology and implemented ‘The SyAct System’ that combines a state-of-the-art handpiece with cutting-edge fluid engineering and nanoparticle technologies, which will be released later in 2021.”

• Shape: “TruShape and TruNatomy rotary files (Dentsply Sirona) improve three-dimensional canal wall contact and canal debridement. These narrower files provide clinicians with proper cleaning and shaping principles while preserving the endo/resto complex.”

• Pack: “I prefer heat-softened, 3D gutta-percha techniques, but I am examining core-obturation systems, single cone-based techniques, and others.”

• Sealer: ThermaSeal Plus (Dentsply Sirona)

2. Dr. L. Stephen Buchanan

• Clean: PulpSucker (PS) Multi-canalar Negative Pressure Irrigation System

17% EDTA irrigant during instrumentation.

8% ChlorExtra 2.0 NaOCl run through PS System Catheters for 15 minutes after instrumentation is completed.

• Shape: Traverse Rotary Negotiation Files (Kerr)–single-file negotiation in 85% of canals.

ProLube lubricant until initial negotiation and apex location are completed.

Tri-Auto ZX2 (J. Morita) endo handpiece with embedded apex locator.

NT K-files (Dentsply Maillefer) for gauging.

ZenFlex Shaping Files (Kerr)–single-file shaping.

• Pack: Continuous wave of condensation with Elements IC/System-B (Kerr).

In development—vacuum-drawn Bio-Ceramic Sealer as the final step in PS procedures. (this is 3D obturation without downpacking or backfilling).

• Sealer: Bio-Ceramic Sealer

3. Dr. Gary Glassman

• Clean: “EndoVac (Kerr), through a series of 3 NaOCl microcycles and apical negative pressure, delivers irrigant continuously to the apical terminus without extrusion past the apex using apical negative pressure.”

“The EndoActivator (EA) (Dentsply Sirona), by sonically activating the irrigant solutions, enhances the disinfection process and aids in the removal of tissue and debris within the root canal system.”

“Full-strength NaOCl and QMix (Dentsply Sirona) remove the organic component of the smear layer and disinfect the root canal system while Q-Mix (EDTA plus chorhexidine analoque) removes the organic component of the smear layer.”

• Shape: “ProTaper Gold (PTG) (Dentsply Sirona), with special affinity for SX and ProGlider. PTG produces minimally invasive endodontic preparations when DFUs are followed. PTG is predictable, efficient, safe, and simple for the automatic creation of the appropriate shape for the root that the root canal resides in. The bottom line, PTG maintains root canal systems’ original anatomy. The SX/ProGlider sequence makes shaping with the PTG series a breeze. The SX rapidly and efficiently removes coronal dentinal interferences, and the ProGlider enhances glidepath preparation.”

• Pack: “Vertical compaction of warm gutta-percha using the continuous wave of condensation utilizing the Gutta-Smart Pack and Flow device (Dentsply Sirona).”

• Sealer: “ThermaSeal Plus Sealer (Dentsply Sirona) offers excellent biocompatibility, minimal shrinkage, and low solubility. Small particle size allows for obturation of narrow anatomy, including accessory and lateral canals.”

4. Dr. Manor Haas

• Clean: “During instrumentation, I use 2.5% NaOCl as a lubricant and for irrigation. As for final flush, I use NaOCl, then dry canals, and finish with QMix. I agitate both NaOCl and QMix with the EndoActivator for 30-plus seconds per canal. I use a 30-g side-venting endo irrigating needle to deliver these agents.”

• Shape: “I start with C-files (#6, #8, #10) as needed, depending on the size of the canals, followed by PathFiles for exceptionally calcified or curved canals or WaveOne Gold Glider (Dentsply Sirona) for less calcified canals, to obtain a glidepath. I finish with ProTaper Gold files (Dentsply Sirona). I determine the master file size with apical gauging vs a one-size-fits-all technique. For instance, I would tend to instrument larger at the apex in a palatal root of a maxillary molar vs the buccal roots.”

• Pack: “Gutta-Smart with Conform Fit cones (Dentsply Sirona). I absolutely love the ease of use and freedom that these cordless units provide me. And I love the feel and fit of the Conform Fit cones, which I have found to provide much better apical tug-back than other cones I have used.”

• Sealer: “Ribbon. Not bioceramic sealer as it might create problems if the case ever has to be retreated or if post space needs to be prepared after sealer is set.”

5. Dr. John Khademi

• Clean: GentleWave (Sonendo)

• Shape: “Files. V Taper files 17/V.04 (SS White Dental) to ensure sufficient space for GentleWave fluid flow and that canals are obturatable. EAL used to identify that the foramen is reached. In smaller canals, such as an MB2, there is not adequate natural shape for predictable fluid flow, so an adequate fluid path is ensured by taking a small (17/V.04) or very small 14/V.o3 to within 0.5 mm of the apex or full EAL length.”

• Pack: Single cone Buchanan red-label

• Sealer: “EndoSequence BC Sealer (Brasseler USA). These small and extremely small shapes need a very thin sealer/film thickness.”

6. Dr. Charles Maupin

• Clean: “Laser-activated irrigation of sodium hypochlorite, EDTA, and distilled water using the Waterlase (BIOLASE) to generate shockwaves, forcing the irrigants throughout the root canal system.”

• Shape: “Size 15/04 to 20/06 EndoSequence Scout files (Brasseler USA). The shape is created only to allow a pathway for the pressure waves created from the Waterlase laser to travel throughout the root canal system.”

• Pack: “Modified warm vertical technique. A narrow anterior Touch ’n Heat tip (Kerr) is used for a deep-down pack, followed by a backfill using the Hot Shot.”

• Sealer: “My preferred sealer is Pulp Canal Sealer EWT (Kerr), which has a long track record of success. The powder allows the operator to control the consistency of the sealer. Coming in a close second would be EndoSequence BC sealer due to its ease of use.”

7. Dr. Tom McClammy

• Clean: “Since 2017, I have been utilizing GentleWave technology. While I do not think it is the perfect system, I do believe that it is the closest thing we have to debride, disinfect, and therefore ‘clean’ the RCS. There will undoubtedly be innovations in the future that compete with GentleWave, but I think it is the best we have right now.”

• Shape: “When addressing specifically NiTi instruments, today I am able to use fewer (2 to 3) and smaller instruments: for example, 14/.03, 17/.03, and 20/.06 VT from SSW. Of special focus is preserving peri-cervical dentin and producing a sufficient-size tunnel from orifice to foramen.”

• Pack: A single, non-standardized cone­fit validated with EAL and a digital image.

• Sealer: “EndoSequence BC sealer, which is now being marketed by numerous dental companies.”

8. Dr. Blake McCray

• Clean: “GentleWave disinfection 90% of the time and EndoActivator irrigation 10% of the time.”

• Shape: “ProTaper Gold on every case. Always finish with F1 unless a canal dictates a larger size.”

• Pack: “Single cone on every case with matching ProTaper Gold gutta-percha.”

• Sealer: EndoSeal MTA

9. Dr. Terry Pannkuk

• Clean: “Chlorox Ultra (8.25% NaOCl) is the mainstay irrigant; alcohol is used to clear between irrigants; 17% EDTA is used at the end to clear and then dry with alcohol. An ultrasonic file (ACTEON North America) is used on low power to activate the irrigant. Most recently, I am using a patented intracanal form of trichloroacetic acid (TCA) as a pulp dehydrant. The observable benefits are (1) it more efficiently establishes patency; (2) it allows easier file entry for tight, small, calcified canals; (3) it decreases postoperative pain; (4) enhanced cleaning; and (5) more. Launching in 2021.”

• Shape: “Precurved K-files and ProTaper Gold S1 to F3, depending on the anatomy. Passive Gates Glidden burs for initial flaring.”

• Pack: Vertical compaction of warm gutta-percha technique.

• Sealer: “Kerr regular set (ZOE). EndoSequence BC Sealer monobloc for resorbed large portals of exit when gutta-percha cannot be controlled.”

10. Dr. Reid Pullen

• Clean: “I predominantly use EndoActivator but also GentleWave on certain cases. Once shaping and conefit are finished, I run EndoActivator for 30 to 60 seconds in each canal, followed by EndoVac, followed by EndoActivator again with QMix to remove the smear layer.”

• Shape: “I predominantly use ProTaper Gold S1 to F3. With smaller, tighter canals, I will finish with F1. I also use the WaveOne Gold reciprocating system.”

• Pack: “Vertical compaction of warm gutta-percha. I use the cordless Gutta-Smart heat tip (black tip) for downpack and the Gutta-Smart 25-gauge tip for backfill.”

• Sealer: Thermaseal Ribbon (Dentsply Sirona) or Kerr pulp canal sealer

Figure 3. The Future. (a) A virtual headset to see an endodontic tooth in 3D. (b) Targeting all foramina (courtesy of Tooth Atlas). (c) Smartphone pack app activated. (d) Shooting seal bullets. (e) Foramina sealed. (f) The anterior teeth would discolor due to untreated necrotic pulp. In this aesthetic situation, it is time to access, vacuum root canal system contents (this is good anyway, as latent bacteria could creep out from the foraminal seals), and then fill the root canal system. Then correct the discolored tooth with either “walking bleach” or veneer or maybe some futuristic paint!

Survey Observations and Trends from the 10 Respected Endodontists

1. None of these endodontists do the same thing! There is more than one way to bake a cake. This should say something profound to the reader. The greatest variable may not be the tools of the Triad; it is you and me—our skills and our willingness to show them off.
2. All those surveyed enjoy enormous clinical success. All have robust recall systems. They all have a penchant for seeking proof of positive outcomes.
3. All of the above aspire to be their best.
4. All are lifetime students and resist just trying to be right. Their “rightness” comes from maximizing predictability and shrinking their “X” to 100% − x.
5. Endodontics is still extremely meticulous and, regardless of advancing technology, resolving to honor the fundamental basics of root canal system treatment remains indispensable for predictable success.
6. Cleaning the root canal system is the new frontier in endodontics. In the past, this Triad member was the one most ignored.
7. Canal shapes are becoming narrower due to innovations in cleaning and filling, which preserve the natural anatomy of the root canal system.
8. The concept of minimally invasive endodontics (MIE) is becoming mainstream.¹² However, remember the pendulum always swings back and forth, and in the case of endo­dontics, the pendulum is swinging between disruptive technology and time-tested fundamentals.¹³ In addition, adhesive dentistry is not so focused on minimal access size or ferrule preservation.
9. Obturation techniques are becoming easier and more simplified.
10. Some of the endodontists were antithetical toward the 3-word Triad and want to instead call it a “Biad.” Others might see the Triad as a “Uniad.” To me, all the parts of the Triad are perfectly intact and required. It is only the emphasis and delivery of the Triad’s parts that are being challenged and are changing.
    The answers to my survey were edited in the interest of article word count. However, all the doctors surveyed invite you to contact them if you want to learn more from them (see next page).

THE FUTURE
The Endodontic Triad is alive and well. Many endodontic companies and inventive endodontists are investigating more predictable ways to treat endodontic disease. For example, I can report as a Dentsply Sirona KOL leader/designer that much energy and innovation is being given to the 2021 launches of products addressing all 3 parts of the Endodontic Triad as well as sealers.Peering into the future, sometimes innovations can become fantasies, and sometimes these mysterious and abstract fantasies become reality (Figure 3). But the “X” in 100% − X is about to become a smaller “x.”

MY INVITATION TO A 10-STEP OPERATORY MINDSET
This article is full of endodontic strategies; recipes; and prescriptions for tools, techniques, and technology. Most require some learning curve, purchase, and change. But I invite you, the reader, to improve your endo­dontic predictability without lifting a finger. Are you all ears? It is a mental shift.¹⁴ For the next 2 weeks, when you enter the operatory to treat an endodontic patient, I encourage you to savagely focus on this 10-Step Mindset of where you want to go:

1. I am slowing down. In the words of Simon and Garfunkel (1960s), “Slow down, you move too fast/You got to make the morning last.” Remember, slow and steady wins the race.
2. I am designing my access so that I am finding all the canals but with respect to a “maximally” appropriate access size and shape—not too big and not too small, just right.
3. I am taking the time to identify all orifi.
4. I am removing restrictive orifi dentin triangles before sliding down the canal.
5. I look at pretreatment periapical radiographs and vividly imagine the desired final radiographic result.
6. I am proceeding with a lighter touch than ever before, knowing root canal systems are delicate and require restraint vs pushing.¹⁵
7. If I am behind schedule, I choose to close the access and reschedule. The clock is the kiss of death in endodontics.
8. I irrigate after every endodontic instrument is removed from the canal and before re-entry. I recurve the manual file on each re-entry.
9. I stop myself if I am thinking negative thoughts about how I am doing and experiencing my endodontic treatment. As soon as I notice that I am following my mind to a place I do not want to go, I just understand where this thought is taking me. I hear the nonstop voice in my head.
10. That’s it! There is nothing for me to do. Just observe! I sit back and watch myself do something different, something that moves me toward experiencing the real outcome I wanted in the first place.

By seeing, feeling, and thinking this 10-Step Mindset, you will measurably improve your endodontic outcomes. Your brain will literally rewire, and new neural networks will form. Because of the brain’s neuroplasticity, we can train the brain by what we focus on. You will have a new normal! Call me if it does not work! There is magic and freedom in what I am suggesting to you.

In summary, stay tuned. Things are changing in endodontics, maybe even in pulp regeneration, but remember that fundamentals are still the salient ingredient of predictability.

CLOSING COMMENTS
The Endodontic Triad is changing, and at an increasing rate, CSP will change, and the vocabulary of CSP will probably change with new tools, techniques, and technology. During these changes, what is our responsibility to the public? Do these changes close the 100% − X to essentially 0%? What will the changes cost? How long is the proving time? What if cleaning better is not better or really does not matter? What if the need for clinician shaping is eliminated or performed by robotics? What if packing material is a miracle future filler that easily bonds with the entire root canal system’s walls by the push of a button?

However, technology can fail. Do you remember the promise of N2, Hydron, and Resilon? All were removed from the marketplace. Do you remember Canal Finder? It is our responsibility to our patients to be the gatekeepers of new technology benefits. Early adopters of new technology always take a risk, but it should not be our patients’ risk.

The race for the ultimate Endodontic Triad is on. The Endodontic Triad is Alive and Well! And it will be different.

In closing, here’s one more lasting thought: Let endodontics be whatever it becomes.

And now your next endodontic patient has a question: Are you ready for the moment?

RESOURCES
To contact any of the endodontists who contributed to this article, please see the contact information below.

Dr. George Bruder: gbruder@idifl.com
Dr. L. Stephen Buchanan: lstephenbuchanan@gmail.com
Dr. Gary Glassman: gary@rootcanals.ca
Dr. Manor Haas: manor@drhaas.ca
Dr. John Khademi: jakhademi@gmail.com
Dr. Charles Maupin: drmaupin@maupinendo.com
Dr. Tom McClammy: drmcclammy@nsendodontics.com
Dr. Blake McCray: bwm.dds@gmail.com
Dr. Terry Pannkuk: terry@pannkuk.com
Dr. Reid Pullen: reidpullen3@hotmail.com

References

1. West JD. Rules of engagement: Mastering the endodontic game, part 1. Dent Today. 2006;25(6):94-101.
2. Friedman S. Prognosis of healing in treated teeth with endodontic infections. In: Fouad FA, ed. Endodontic Microbiology. 2nd ed. Wiley-Blackwell; 2017.
3. Schilder H. Filling root canals in three dimensions. Dent Clin North Am. 1967:723-744.
4. Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974;18:269-296.
5. Ruddle CJ. Endodontic triad for success: The role of minimally invasive technology. Dent Today. 2015; 34:76-80.
6. The Ruddle Show. Ruddle Projects & Diagnostic Imaging. S03:E07. www.theruddleshow.com. Released November 25, 2020.
7. West JD. The endodontic glidepath: Secret to rotary safety. Dent Today. 2010;29(9):86-93.
8. West JD. The three Fs of predictable endodontics: Finding, following, and finishing. Dent Today. March 1, 2016:90-96.
9. West JD. Endodontic predictability: What matters? Dent Today. September 16, 2013:108-113.
10. West JD. Root canal system anatomy only matters when it matters. Endo Practice U.S. December 30, 2015:56-58.
11. West JD. The evolving look of “the look.” Dent Today. June 1, 2019:62-66.
12. Khademi J. Restoratively driven, minimally invasive endodontics. Dent Today. January 1, 2019:66-69.
13. West JD. The pendulum swings. Dent Today. July 1, 2019:8-10.
14. West JD. The set up: Endodontic predictability. Dent Today. September 1, 2020:66-71.
15. West JD. Restraint: The lost art of endodontics. Dent Today. July 1, 2018:100-103.

Dr. West received his DDS degree from the University of Washington, where he is an affiliate professor, and his MSD degree in endo­dontics from Boston University, where he was honored with the Distinguished Alumni Award. Dr. West is founder and director of the Center for Endodontics in Tacoma, Wash, where he is in private endodontic practice. He can be reached at (253) 377-2007 or via email at johnwest@centerforendodontics.com.

Disclosure: Dr. West is co-inventor of ProTaper, ProGlider, WaveOne, Gold Glider, and Calamus products.

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