Continuing Education A Logical Rationale for Endodontic Therapy

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Continuing Education

A Logical Rationale forEndodontic Therapy:

Understanding the Rules of the Game

Authored by Lisa Germain, DDS

Upon successful completion of this CE activity 2 CE credit hours will be awarded

Volume 33 No. 8 Page 72

ABOUT THE AUTHORDr. Germain graduated from BostonUniver sity School of Graduate Dentistrywith a specialty degree in endodontics in1981. She is a Diplomate of the AmericanBoard of Endo dontics, on the Faculty of theAmerican Acad emy of Facial Esthetics,

and a Fellow of the In ternational Congress of Oral Implantol -ogists. She maintains a private practice in New Orleans andserves as the clinical director for DC Dental. She can bereached via e-mail at [email protected].

Disclosure: Dr. Germain reports no disclosures.

INTRODUCTIONIn 2005, New Orleans was devastated by hurricane Katrina.The Super dome, home to our beloved Saints football team,sustain ed severe damage, and many thought the Saintswould never play there again. Ulti mately, however, theSuperdome was re paired and renovated in time for the2006 season. The Saints’ first post-Katrina home event wasan emotionally charged Monday Night Football gameversus their division rival, the Atlanta Falcons. The Saintsdefeated the Falcons 23 to 3. Later that season, they wonthe first divisional playoff game in franchise history. Threeyears later they won 13 games, qualified for Super BowlXLIV, and defeated the American Football Conferencechampion In dianapolis Colts 31 to 17. This historic gameunited a city that had just about lost hope and became anexample to all about overcoming obstacles to achievesuccess against great odds.

Is it any wonder that when I hear dentists say that rootcanal therapy does not work, I am blindsided? Is it possiblethat my life’s work has been for naught? Have the

thousands of natural teeth that I have treated throughoutthe years been extracted and re placed with implants? Is itpossible that a prosthetic device is better than anyotherwise healthy organ in the human body? If so, why do Ibother to get out of bed in the morning?

Don’t get me wrong. I believe in im plants and placethem. When a tooth cannot be saved, an implant is thetreatment of choice. After all, it is easier to win if you have arunning game and a passing game.

The impact that implants have on our ability to restorepatients back to function and aesthetics is immeasurable.However, implants and root canals, while not mutuallyexclusive, have completely different indications. A rootcanal is treatment for a diseased tooth, and an implant istreatment for an edentulous space. To suggest that they areinterchangeable is naïve.

Pregame PreparationMy mentor, Dr. Herbert Schilder, preached a unique andvisionary catechism for his time. His enduring doctrine hasnot only shaped modern endodontics, but it will serve as amodel for excellence forever. I am a proud disciple of Dr.Schilder, and this is what he taught us the very first day inmy Boston University (BU) residency.

“Inside every tooth there is a piece of soft tissue that issusceptible to necrosis, gangrene, and death” (according tolecture notes from H. Schilder, BU, Henry M. Gold manSchool of Dental Medicine, 1979).

Pulp tissue is compromised from the start, and dies for3 reasons:

1. The tissue has a very small blood supply, making itvery difficult to regenerate on its own once it is injured.

2. It lies inside the unyielding walls of dentin and,therefore, when it becomes inflamed, it does not have roomto swell.

3. It is a terminal circulation, like the appendix, whichonce diseased, needs to be removed.

The most common cause of pulpal pathology is caries,with trauma being the second. Add in parafunction, plus the in flam mation that is created from dental procedures, and it is amazing that any pulps actually remain vital andasymptomatic. For tunately, many do, but the higher thefrequency, duration, and magnitude of the injury to the


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A Logical Rationale forEndodontic Therapy: Understanding the Rules of the GameEffective Date: 8/1/2014 Expiration Date: 8/1/2017

tooth, the more likely the pulp will succumb to an irreversiblepathological change.1,2

Strategy of the Offensive Coordinator Knowing what you have, what you don’t have, and makingthe necessary adjustments.

A root canal system is a complex anatomical spacewithin the root of the tooth. It is never just a single tube, andfurthermore, no 2 are alike. Each tooth must be evaluatedwith a unique treatment plan in mind. Most canals terminatein the periodontal ligament (PDL), at an exit point close tothe end of the root. However, it is common for a root canalsystem to have more than one exit point. These portals ofexit (POE) can occur anywhere along the cementum of theperiradicular anatomy, but are quite common in the apicalone third (Figure 1).

When the pulp begins to break down, the bacterial by-products of cellular necrosis egress from within the rootcanal system in a coronal to apical direction, through thePOE, and into the surrounding PDL and bone. Someexamples of these noxious materials include enzymes suchas sulphatases and hyaluron idases; and inflammatoryagents such as prost aglandin E2 and tumor necrosis factor-alpha. These toxins, in turn, will destroy the healthyperiradicular tissues and create bone loss; this is called alesion of endo dontic origin (LEO) in “endo-speak.” Since theLEO arises secondary to the pulp tissue breakdown, thedisease source is the tooth and the effects are manifestedin the bone.1,2

Dr. Schilder taught that root canal success could be100%. An extraction will eliminate all of the leakage fromthe POE and bone healing will occur, but it will alsoeliminate the tooth. So, by cleaning and shaping a rootcanal system and sealing all of the POEs, the bone has thesame potential for healing.1 Why, therefore, are we not alldancing in the end zone?

In reality, the formula for endo dontic success is 100%-x,with x being the tangible and intangible limitations of theclinician. Examples of the tangible limitations are theinability to negotiate a canal, how well the isthmus can becleaned, difficulties in establishing patency, and othermechanical challenges during the cleaning, shaping, and 3-dimensional obturation procedures. The intangible factors

are related to human nature, such as patient cooperation,an inability or reticence by patients to keep their mouthopen for the duration of the treatment, how much theclinician is able or willing to focus at that instant, and so on.3

We all come to the playing field with different levels ofskill, unique notions and bias, and varying degrees ofdetermination. However, the key to obtaining excellence inany endeavor is the desire to improve. Saving teethrequires practice for the mechanical procedures, continualstudy of the science, and the desire to merge the 2 for thepatient’s well being. Because ultimately, x begs the questionof how far we (the operators) are willing and able to carrythe ball.

CASE REPORTSCase 1 A 72-year-old male patient presented with spontaneouspain and mild facial cellulitis. Pain to percussion, palpation,and biting were reproduced on tooth No. 21. Figure 2areveals radiographic evidence of bone pathosis in theperiradicular apical third that provided further confirmationof the odontogenic origin of the symptoms. A diagnosis ofacute alveolar abscess was made, and the root canalsystem was thoroughly cleaned, shaped, and obturated in3 dimensions. The postoperative radiograph in Figure 2bshows a complex root canal system with several POEs thatcoincided with the location of the periradicular le sion. The 9-month follow-up radiograph in Figure 2c reveals goodbone regeneration.

Case 2A 68-year-old female patient was re ferred for retreatment oftooth No. 19. However, the chief complaint of biting pain and


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A Logical Rationale for Endodontic Therapy: Understanding the Rules of the Game

Figure 1. MicroCT image of anextracted lower premolarillustratingaccessory canalsand multipleportals of exit(POE). (Scanprovided byMarco Versiani,DDS, MS, PhD.)

palpation tenderness werereproduced on tooth No. 18.Figure 3a reveals insufficientcleaning, shaping, and obturationof the root canal system in toothNo. 18. After retreatment, alateral canal with a lateral POEwas filled (Figure 3b). This casedemonstrates the importance ofusing endodontic testing toconfirm symptoms andradiographic findings. It alsoshows that poorly performed rootcanal therapy does not justifyextraction without consideringretreatment as a viable option.Not all teeth with nonhealingendodontic treatment arecandidates for retreatment, buteach unique set of circumstancesshould be considered before thetooth is sacrificed.

Case 3The origin of a radiolucent area in the furcation can presenta diagnostic challenge, and a LEO is often mistaken for alesion of periodontal origin or a root fracture. Since properdiagnosis is the key to successful resolution of each ofthese disease processes, a thorough understanding of thediagnostic profile of each is paramount.

A 41-year-old female patient was referred forendodontic treatment on tooth No. 30. Radiographicimaging revealed a radiolucent area located in the furcationbetween the roots of tooth No. 30 (Figure 4a). The toothtested nonvital to electric pulp testing (EPT), and wasnonresponsive to cold, indicating the presence of a nonvitalpulp and hence an endodontic disease process. There wasno mobility or deep pocketing, and the furcation could onlyslightly be probed. These findings, plus the absence ofperiodontal disease in other areas, led to a diagnosis ofprimary endodontic pathosis with secondary periodontitis.

The postoperative radiograph (Fig ure 4b) reveals alateral canal leading to a POE that exited into the furcation.

A one-year follow-up radiograph indicated furcation andperiradicular healing (Figure 4c).

Figure 5 shows a scanning electron microscope imageof a substantial lateral canal in the furcation of an extractedmo lar. When a lateral canal is present in the furcation of atooth, it can mimic the signs of periodontal disease or a rootfracture. Proper differential diagnosis is the key tosuccessful resolution of any combined lesion.

Case 4One of the most frustrating clinical situations is a seeminglyperfect root canal treatment that remains symptomatic. It isvitally important to be persistent in resolving the pathosis,and a systematic approach is necessary.

A 48-year-old female pa tient presented with pain topalpation, percussion, and biting on tooth No. 5. The clinicalexamination revealed a localized indurated swelling on thebuccal mucosa, approximating the periapex of the tooth.The periodontal examination was within normal limits. Adiagnosis of acute alveolar abscess was made, andnonsurgical root canal therapy was performed (Figure 6a).


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Figures 2a to 2c. (a) Pre-op, tooth No. 21. (b) Post-op, No. 21 showing multiple POE. (c) Nine-month follow-up of periradicular healing No. 21.

a b c

Figures 3a and 3b. (a) Pre-op retreatment, tooth No. 18. (b) Post-op retreatment, No. 18.

a b

The postoperative radiograph of tooth No. 5 revealed acompleted root canal with a filled bifid terminus and lateralcanal (Figure 6b). Even Dr. Schilder would have agreed thatit had “the look.” How ever, the patient presented severalweeks later with persistent symptoms, and only slightresolution of the induration in the mucosa. Non surgicalretreatment was performed, and the postoperativeradiograph revealed another filled lateral canal that exited ina lateral LEO (Figure 6c). When the patient re turned for thefollow-up appointment several weeks later, she reportedthat her symptoms had not resolved. (Really? I was sure Ihad gotten it that last time around.)

Sometimes the complexity of the root canal systemevades even the most thorough cleaning, shaping, and 3-Dobturation. An apicoectomy with a root end filling wasperformed (Figure 6d). Figure 6e shows healing of theperiradicular bone one year later. The patient has remainedasymptomatic.

THE RED ZONE Where Play Selections Matters Most!In August 2009, an American Academy of Implant Dentistrypress release stated, “...times have changed, and patientsshould forego prolonged dental heroics to save failing teethand replace them with long-lasting dental im plants.” While itis our responsibility to treat with a predictable result in mind,extracting a tooth without considering other options is notalways in the patient’s best interest. The use ofmicroscopes, ultrasonics, and mineral trioxide aggregate(MTA) has improved our ability to treat and preserve teeththat otherwise may have been prematurely judged ashopeless. In addition, there are patients who want to try

anything possible to save their natural teeth. While I wouldnot treat a tooth that I knew was hopeless, I am oftenamazed at the successful treatment results seen in many“heroic” cases. The challenge really becomes knowingwhen not to throw a hail Mary pass.

Case 5A 38-year-old female patient presented with a postperforation in the dis tal/lingual canal through the furcationof tooth No. 30. Figure 7a reveals bone loss in the furcation.Figure 7b shows a sinus tract traced to the point of postperforation. After advising of a guarded prognosis, thepatient chose to attempt “heroic” measures to attempt tosave her tooth. The post was removed, and MTA was usedto seal the perforation (Figure 7c). At the 6-month follow-upappointment, the sinus tract was healed. In addition, theradio graphic image revealed bone regeneration in thefurcation (Figure 7d).

Case 6A 65-year-old female patient presented with pain topercussion and biting on tooth No. 31. Radiographicevidence of a separated instrument and a possible


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Figures 4a to 4c. (a) Pre-op, tooth No. 30 1˚ endo/2˚ perio. (b) Post-op, No. 30. (c) One year follow-up showing periradicular and furcationhealing.

a b c

Figure 5. Scanningelectron microscopeimage of a substantiallateral canal in a molarfurcation.

perforation in the mesial rootsystem (Figure 8a) made theprognosis for a nonsurgicalretreatment guarded. Sur gerywas considered; however,access to the area was poor.The patient was adamant abouttrying everything possible tosave her tooth. After exploringall options, the patient chose tohave an intentional replanta-tion procedure. The tooth wasextracted atraumatically, the apical POE as well as the rootperforation were sealed, and then the tooth was reimplanted inthe socket—all within 5 minutes of the extraction. Figure 8b isa radiograph taken immediately after re-implantation. Figure 8cshows a removable splint that functioned to stabilize the tooth after treatment. Figure 8d is a 2-month follow-upradiograph. A clinical examination at that time confirmed that the tooth was stable and asymptomatic. Figure 8e is a 6-month postoperative radiograph. Figure 8f is apostoperative radiograph taken at 8 years.

To recommend extraction of a tooth prior to confirmation ofa hopeless prognosis is like punting on the first down withplenty of time on the clock—not a good strategy. While aradiographic image or a CBCT scan can give you a preview ofwhat to expect, actual exploration and visualization of anystructural defect that may preclude successful root canaltherapy is the best way to confirm that a tooth has a hopelessprognosis. There are 2 ways to approach this dilemma.

Case 7A 49-year-old male patient was re ferred for endodontictreatment on tooth No. 14. A radiographic image (Fig ure 9a)revealed an amalgam restoration and canal calcification. Theclinical examination revealed a mesial-lingual cusp fractureand re current decay. The tooth tested nonvital to heat, cold,and EPT. There were no periodontal defects that could beprobed. Anesthesia was given, a rubber dam was placed, andthe amalgam restoration was removed. Once access wasmade, an obvious fracture was de tected that extended fromthe mesial marginal ridge to the distal marginal ridge acrossthe floor of the pulp chamber (Figure 9b). While an initial

diagnosis of acute alveolar abscess was made, the ultimatediagnosis proved to be fracture necrosis, and extraction withimplant placement was recommended.

The hopeless prognosis of this tooth was not evident at theoutset of the case. It did not have the classic signs of a rootfracture either clinically or radiographically. In order todetermine eventual prognosis, the restoration was removed,and nonsurgical exploration allowed for visualization of the


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Figures 6a to 6e. (a) Pre-op, tooth No. 5. (b) Post-op, No. 5. (c) Post-op No. 5, after retreatment. (d) Post-op No. 5, after surgery. (e) One-year-follow up.

a b c

d e

Figures 7a to 7d. (a) Pre-op post perforation, tooth No. 30. (b) Sinustract traced to perforation. (c) Post-op and mineral trioxide aggregateseal. (d) Six-month follow-up.

a b

c d

defective tooth structure. If a restoration suchas a crown, post and core, or amalgam isobstructing the view of the remaining toothstructure, it needs to be removed prior todetermining prognosis for root canal therapy.

Case 8 This 68-year old male patient reported forretreatment of tooth No. 30. The radiographicimage (Figure 10a) re vealed an inadequateroot canal treatment, periradicular radio-lucencies on the mesial and distal roots, andfurcation bone loss without generalizedperiodontal disease. The clinical examinationrevealed a sinus tract at the cervical area ofthe tooth on the attached gingiva (Figure 10b)and +1 mobility. Normal 3.0 mm sulcusdepths were found upon probing around theentire tooth, except on the mesial-buccal,where a 10.0 mm (narrow and isolated)periodontal pocket was probed. While thedifferential diagnosis included a lateral canalin the furcation or an isolated periodontaldefect, a root fracture was suspected as theprimary cause of the pathosis.

Anesthesia was givenand a full-thickness flap wasreflected (Figure 10c) toreveal a root fracture of themesial-buccal root, alongwith an associated bonydehiscence. An atraumaticextraction was performed,and then a bone graft wasplaced in the 4-wall defect topreserve the ridge forultimate implant placement(Figures 10d and 10e).Surgical exploration isanother way to visualize defective tooth structure, particularlywhen there is a high probability that an extraction will benecessary. While the first intention should be to save the tooth,the next priority is to save the site. When a fracture has

destroyed bone, saving the site for future implant placementbecomes the priority over heroic endodontics.


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Figures 8a to 8f. (a) Pre-op intentional replantation, tooth No. 31. (b) Post-op, No. 31. (c) Splintin place. (d) Two-month follow-up, No. 31. (e) Six-month follow-up, No. 31. (f) Eight-year follow-up, No. 31.

a b c

d e f

Figures 9a and 9b. (a) Pre-op tooth No. 14. (b) Fracture from the mesial marginal ridge tothe distal marginal ridge across the chamber floor.

a b

Figures 10a to 10e. (a) Pre-op suspected root fracture,tooth No. 30. (b) Sinus tract on attachedgingiva. (c) Root fracture MB root. (d) Post-extraction. (e) Post-bone graft.

a

d e

b c

THE FINAL SCOREIt takes little effort to be a Monday morning quarterback;hindsight is 20/20. We have an ethical responsibility to providepatients with the most conservative, cost effective, predictabletreatment in order to restore function, aesthetics, and oralhealth. If the tooth is restorable; if the perio dontal condition isstable or can be made so; and, if the root is intact, saving thetooth should be considered. But, if there is a high risk that thesite for a future implant would be compromised, heroicendodontic treatment should not be a first choice.

Vince Lombardi is quoted as having said, “We wouldaccomplish many more things if we did not think of them asimpossible.” And, while we can’t expect to put it through theuprights on every offensive possession, it is important toknow what is possible.

REFERENCES 1. Schilder H. Cleaning and shaping the root canal. Dent

Clin North Am. 1974;18:269-296.2. Yu D. Radiographic location of accessory canals. Private

Dentistry. February 2006:36-43.endoexperience.com/documents/EndoAccessoryCa -nals.pdf. Accessed on June 2, 2014.

3. Bellamy R. Endodontic success: “100% - X.” En do donticPractice. January/February 2013;6:26-27.


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POST EXAMINATION QUESTIONS

1. The higher the frequency, duration, and magnitude ofthe injury to the tooth, the more likely the pulp willsuccumb to an irreversible pathological change.

a. True b. False

2. It is common for a root canal system to have morethan one exit point. These portals of exit (POEs) canoccur anywhere along the cementum of the peri-radicular anatomy, but are quite common in theapical one third.

a. True b. False

3. Since the lesion of endodontic origin arisessecondary to the pulp tissue breakdown, the diseasesource is the bone, and the effects are manifested inthe tooth.

a. True b. False

4. By cleaning and shaping a root canal system andsealing all of the POEs, the bone has the samepotential for healing.

a. True b. False

5. It also shows that poorly performed root canaltherapy always justifies an extraction.

a. True b. False

6. Proper differential diagnosis is the key to successfulresolution of any combined lesion.

a. True b. False

7. Sometimes the complexity of the root canal systemevades even the most thorough cleaning, shaping,and 3-D obturation.

a. True b. False

8. While a radiographic image or a CBCT scan canprovide a preview of what to expect, actual explorationand visualization of any structural defect that maypreclude successful root canal therapy is the best wayto confirm that a tooth has a hopeless prognosis.

a. True b. False


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Continuing Education A Logical Rationale for Endodontic Therapy