EndoImplantology: A Retrospective in the Paradigm Shift in Endodontic Therapy

When a patient is referred for endodontic therapy to an endodontic specialty practice, is root canal treatment necessarily indicated? Could a tooth referred for extraction and implant placement to an oral surgeon possibly be saved by an endodontist? Is crown lengthening becoming obsolete due to the shift in our abilities to prioritize bone and soft tissue architecture over damaged and/or weakened teeth? How does one decide on a particular treatment, and what are the parameters used in the decision making process in the blurred arena of challenging cases? Does having a hammer make us see everything as a nail?
Ultimately, "To save, or not to save?" is the question for which the exponential development and diffusion of implantology and regenerative sciences has made the answer more difficult than ever before—unless of course you are dealing with just a "hammer and a nail."
In this 2-part article, and in upcoming articles, I will present new philosophies and ways to approach the endodontic-implant connection.

INTRODUCTION AND BACKGROUND
I am an endodontist by training, and my clinical and research path over the last 25 years led me to create EndoSphere and EndoImplantology as my integrative clinical practice. EndoSphere represents a global approach to endodontics, where build-up and crown-lengthening are an integral part of the treatment plan involving root canal therapy (Figures 1a and 1b). Eventually, my extensive clinical exposure to endodontic retreatment, as well as my research background in bone biology and growth factors, was instrumental in the creation of what is now referred to as EndoImplantology. Developed in the mid 1990s to address retreatment, the new algorithm and its associated decision-making tree was extended over the years to cracked/fractured teeth, roots with resorption, hypercalcified canals, and/or simply teeth with poor extrinsic value. Ultimately, the question of long-term prognosis (LTP) became central to the process.
In 2005, I introduced this new concept in endodontics at the 62nd American Association of Endodontics (AAE) annual session with a lecture entitled: "EndoImplantology: A Paradigm Shift in Endodontics," also the title of an article that I had published in that same year.1 The lecture was the result of a decade of development progressively incorporating immediate grafting, the concept of computed tomography scanning for endodontics, and eventually immediate implant placement. From its introduction in this lecture, the field has expanded as witnessed at the 2009 AAE (66th) Annual Session in Orlando. Now, this new trend has acquired its own momentum and is changing the way endodontics is taught today in graduate programs. Perceived at the beginning as a threat to endodontics it is in fact what will help to save the specialty by giving more credibility to the endodontists who are cognizant of alternative treatments. EndoImplantology is not a "conflict of interest." It is a conscious, holistic, and realistic approach to care, with its core value centered on natural tooth preservation whenever possible.
Part 1, of this 2-part article, describes the origin of the paradigm shift in endodontics, and its implications from a diagnosis and decision-making standpoint. Part 2 of this article will go on to expose the original classification developed for the surgical approach of EndoImplantology.

LIFE AS AN ENDODONTIST

Figure 1a. A patient is referred for treatment of No. 15 after recurrent decay is found under a large amalgam. The extensiveness of the existing amalgam, as well as recurrent decay immediately raises the question of restorability, evoking the possibility of crown lengthening.

Figure 1b. Is the root canal system negotiable? Do we start with root canal therapy, crown lengthening, or should we be ready to extract? What would be the best logistics for timely management of the patient’s challenge?

Figure 2. Ever-larger lesions: It used to be said that a lesion (radiolucency) larger than 2 cm was a cyst. Does that information influence your approach, or should you just extract? If you extract do you graft, or do you wait?

Figure 3. Calcified/nonexistent canals: The crown of this extremely calcified No. 7 just broke. How would today’s planning differ from what we would have done 10 years ago?

"Endodontics, or root canal therapy, is a dental treatment that enables you to save a tooth that would otherwise have to be extracted" is written in the first few lines of our consent form. The only alternative to root canal therapy was at one time extraction and, by all means, nobody wants to lose a tooth. That somber alternative encouraged the practice of a subspecialty: "HeroEndodontics." With passion in hands, the mastering of a task opens the door to the next challenge—ever larger lesions (Figure 2), calcified or nonexistent canals (Figure 3), cracked roots (Figures 4a nd 4b), resorption (Figure 5), perforations, ledges and blocked canals2—all demonstrating what endodontics could do along with actually preserving the prized tooth of the patient. Bone regeneration was achieved predictably before the term even existed.3 Even fractured teeth or extensively decayed abutment were "saved," sometimes at the expense of the surrounding bone and soft tissue. All successes were celebrated as world achievements, while failures were accepted as a part of the risk to attempt the impossible.

HITTING THE FAN: 100 PERCENT MINUS X

Figures 4a and 4b. Cracked tooth: Tooth No. 3 had been sensitive for 2 years despite regular bite adjustments. Eventually, referral was made after a sudden, sharp pain evoked the possibility of a crack. After removal of the floating amalgam, the fracture line on the pulp chamber floor was visualized.

Figure 5. Resorption: Resorption with vertical ramifications running apically. Is this an indication for extraction or endodontic therapy? If endodontic therapy is selected, when would gingival treatment take place? Should endodontics be done in one session? How does the build-up scenario take place?

Figure 6. Nine years after completion of root canal therapy and a build-up, tooth No. 19 presents with a furcal lesion.

Figure 7. An unconfirmed suspicion of a crack led to the decision of whether or not to perform root canal therapy on tooth No. 30. In this case root canal therapy was performed back in 1998. At that time, the suspicion of cracked tooth could not be confirmed by radiographic evidence or even under the microscope.

Over the last few decades, root canal therapy has demonstrated that classic endodontic treatments were at least extremely predictable and reproducible. Along with the increased understanding of how to clean, shape, and seal the root canal system (as promoted by Professor H. Schilder4,5), was the mantra that "a good root canal would work in 100% of the cases minus x; x being the ability of the operator to negotiate the complex system." Experience and time tend to tame expectations, and even though Mother Nature is very good indeed, she also has a mind of her own and "unexpected" failures do arise occasionally. For these patients statistics are meaningless since for them a failure is 100%...of their new predicament. Let’s look at some examples:
In Figure 6, 9 years after completion of root canal therapy and a build-up, tooth No. 19 presents with a furcal lesion. What is the nature of this furcal lesion? Was a canal missed? Are we witnessing a fracture, or is it an iatrogenic resorption? (Note: An existing PFM was removed by the general practitioner before referral.)
In Figure 7, an unconfirmed suspicion of a crack led to the decision of whether or not to perform root canal therapy on tooth No. 30. In this case root canal therapy was performed back in 1998. At that time, the suspicion of a cracked tooth could not be confirmed by radiographic evidence or even under the microscope. The tooth was specifically sensitive on biting on the mesiobuccal cusp. After reviewing our findings and all treatment options with the patient, it was decided that root canal therapy, a bonded build-up, and a PFM would be the treatment of choice. Seven years after that, the patient then presented with an obvious mesial root fracture and a loss of attachment as seen in the periapical x-ray. Finally, in Figure 8, we look at a 7-year span of time. Tooth No. 30 presented with a short endodontic fill and a large post (Figure 8a). The tooth was classically retreated (Figure 8b). Seven years after retreatment the patient presented with swelling, pain upon chewing, and a 12 mm pocket in the buccal aspect of the mesial root (Figure 8c).

Figures 8a to 8c. Seven years after the initiation of retreatment, the patient had swelling, pain upon chewing, and a 12 mm pocket in the buccal aspect of the mesial root.

LOOKING BACK
Retrospectively, should we conclude that extracting all these treated or retreated teeth (Figures 6 to 8) in the first round would have been better? Absolutely NOT! First, the exponential rate of technological improvements (both mechanical and biological) that will be seen in our life time, will make today’s wonders look pale by comparison. Additionally, it is significantly easier to rebound from a "tooth failure" that it is from an "implant failure." We have not yet heard the last of failure rates or complications related to titanium implants. Nonetheless, the experience of these endodontic outcomes, as mentioned earlier, prompted the creation of a new entity called the "Endodontal" failing site (EFS) (Endodontal is a term created by the author). When intercepted, an EFS can open the horizon of our investigation and possible treatment options.

ENDODONTAL FAILING SITE
There is a "natural," unfortunate, egotistical and purely human tendency to blame our own misery on others—such as the failure of previously done root canal treatment. Yet the "world or retreatment" is not the only challenge that root canal therapists are facing. Plenty of teeth that need a root canal have "future failure" written all over. Some of the main reasons are restorability, poor intrinsic value, unpredictable negotiation of root canal system, bone lesions, roots resorption, fracture, iatrogenic damages to name a few.

Figure 9. “Endodontal” failing site (EFS) blending man-made and natural challenges. Tooth No. 31 was referred for an acute apical abscess.

Figure 10. An EFS with multiple challenges. A painful abscess awakened this patient from a dormant 20-year-old root canal on tooth No. 12.

Figures 11a and 11b. Cases demonstrating the spectrum of endodontic involvement and endoimplantology case interception.

Figure 9 shows an EFS blending man-made and natural challenges. Tooth No. 31 was referred for an acute apical abscess. Dental history and clinical observation confirmed the previous "endodontic treatment" with nonradiopaque paste. A restoration, which had been lost a long time ago, had exposed the dentin to recurrent decay on a large scale. The hypercalcified canals may not allow the complete negotiation of the root canal system. The idea of extracting this tooth in order to place an implant is tempting until the realization sinks in that the patient has an extremely limited opening.
Figure 10 demonstrates an EFS with multiple challenges. A painful abscess awakened this patient from a dormant 20-year-old root canal done in a former Soviet East Bloc country. Deciphering the origins of this EFS will help us to decide on one of the 3 options: (1) classic retreat, (2) surgical retreat, or (3) extraction in view of implant placement.
The encounter of an EFS does not remove the possibility of choosing root canal therapy (classic or surgical) as the option of choice. It is just pointing out that the level of predictability for endodontic treatment is not recognized, and that the field of investigation and treatment is opening up to the possible need of a 3-dimensional (3-D) radiograph, study casts/3-D models, extraction, bone grafting, implant placement, and soft tissue manipulation. This approach characterizes EndoImplantology and the EndoImplantology Case Interception (EICI) during the Consult Intake (CI). The goal is to offer the best possible LTP while genuinely looking at all possibilities.
We are taking into consideration 2 interdependent, yet distinct, entities: the tooth and the attachment apparatus. The tooth itself is more than its root canal system, and restorability is taken into consideration in the decision making process. "Saving" a challenged tooth should not ignore the risk as related to the attachment apparatus. Conservatively, destroying the attachment apparatus to extend the use of a stump may not be the most useful indication of root canal therapy.
Therefore, the concept of EFS embraces all possibilities (man-made or not) of cases where one should question the indication of endodontic retreatment or endodontic treatment—including apicoectomy, hemisection, amputation, and reimplantation.
Furthermore, and ultimately, the recognition and interception of an Endodontic Failing Site triggers the integration (beyond endodontics) of 3-D radiography,6-8 bone grafting and implantology in the elaboration of the treatment plan.
EndoImplantology to the rescue: In any case, once a challenge has been recognized, the very first intention is to save the tooth keeping into perspective that the next priority is to save the site.

EVOLUTION IN IMPLANTOLOGY
As the realm of implantology was going through its own revolution, the field of application evolved; from the intermental foramen space for edentulous patients as described by Bränemark in the early 1980s, to single tooth edentulism; bringing tremors to the foundation of the well-established 3-unit-bridge modality. Direct contact osseointegration9,10 was the only implantology modality when the idea of growing bone from a distance to the implant started to break ground with the cases of immediate grafting or immediate implant placement in EFS.11

ENDOIMPLANTOLOGY CASE INTERCEPTION AND CONSULTATION INTAKE

Figures 12a and 12b. Weighing the possibilities: Tooth No. 31 went through a recent flare up. A fistula has formed. Dental history reveals multiple previous attempt of endodontic treatment including an apicoectomy surgery. Shall we attempt a fourth retreat?

Figure 13. This EFS calls for a solution that will globally offer the best long-term prognosis (LTP). Tooth No. 19 was referred for endodontic evaluation.

Figure 14. EFS and LTP: Tooth No. 18 is referred for evaluation. Based on the extensive recurrent decay under the 3-unit bridge and the large amount of bone loss, is it reasonable to attempt saving the tooth or not?

The clinical spectrum touching endodontics is quite large and goes from the obviously treatable to the obviously untreatable (Figures 11a and 11b). The mental triage in EICI starts with attention to the radiograph and the discovery of its content, attentive listening to the patient’s dental history, understanding the patient’s desires and expectations, and of course the clinical examination. The CI, jolted on a blank sheet of paper, is used as the decision-making process and it is outlined in simple colored graphics. (See the dynamic making of the CI during an EICI at dentistrytoday.com linked to this archived article.)
From the CI and EICI, an analysis of all possibilities is reviewed with the patient. The pros and cons of each option are carefully weighed. On some occasions, it may be decided that there is not enough clinical evidence available to make a final decision and further investigations are necessary—sometimes in the form of exploratory surgery, 3-D radiography, and/or study models. The intention is to present a solution that will globally offer the best LTP. When an option of exploratory surgery is presented, it would be with the understanding that a curative component has to be performed at the time.
Take a look at Figures 11a and 11b representing an example of the spectrum of endodontic involvement and EICI. An irreversible pulpitis in tooth No. 18 (seen still with a temporary crown) is typical of a very predictable and reproducible classic root canal and build-up outcome (Figure 11a), but the x-ray to the right (Figure 11b) shows 4 distinct levels: tooth No. 2 with a gold crown and calcified canals raise the question of intentional endodontics. Tooth No. 5 has reached the end of the line. This EFS enters the realm of EICI. Tooth No. 4 has survived its complication so far, and tooth No. 3 represents a successful transition from an EFS to an immediate (post extraction) implant placement, bone grafting, soft tissue manipulation, and loading.
In Figures 12a and 12b, we are faced with weighing the possibilities. Tooth No. 31 went through a recent flare up (Figure 12a). Since a fistula track, visualized with the placement of a gutta-percha cone (Figure 12b), has recently surfaced and calmed the symptoms, we were asked to retreat. Dental history reveals multiple previous attempts with endodontic therapy, including surgery (apicoectomy). Clinical evaluation confirmed the existence of extensive decay under the plastic build-up, and this tooth had been crownless for several months. This typical EFS raises a lot of questions. Shall we attempt a fourth retreat? If yes, should it be surgical or classical? Is there any risk of not being able to repair the apical defect left behind in the first surgery, or could we remedy this issue during a classic retreatment? Can removing the large mesial post lead to fracture or microcracks of the mesial root, in turn leading to a potential failure?
On the other hand, if the tooth is extracted, can we graft or place an implant immediately? Can a primary stability be generated based on the location of the mandibular nerve? Can a site with an active fistula be grafted immediately post-extraction? (The answer to this question will be found in Part 2 of this article.)
In Figure 13, we see an EFS that calls for a solution which will globally offer the best LTP. Tooth No. 19 was referred for endodontic evaluation. Most of the decay has been removed by the referring general dentist. There are no other pathologies and no chief complaints. What is the projection of the LTP for tooth No. 19? Can the root canal system be negotiated all the way? Does the fact that tooth No. 19 could be used as a "stand alone" or the abutment of a bridge change our perspective on how to handle this case? Should our treatment plan consider the need for crown lengthening as well as the reliability of teeth Nos. 17 and 21, if tooth No. 19 was to become the middle pontic of a long span bridge? (We will look at these issues in a future article.)
EFS and LTP: In Figure 14, we see tooth No. 18 as referred for an evaluation. Based on the extensive recurrent decay under the 3-unit bridge and the large amount of bone loss, is it reasonable to attempt saving the tooth, or not? If tooth No. 18 is approached endodontically, should a new bridge be placed, or should an implant be placed on the pontic site at the time of crown lengthening? How does the flow get coordinated? If tooth No. 18 is extracted, should it be grafted immediately? Could an implant be placed at the time of grafting? Can the sequence of bone grafting alone lead to an insufficient height of bone after maturation? Would the placement of an implant be consequently jeopardized?

THE REALM OF ENDOIMPLANTOLOGY
There are 2 distinct phases in the EICI cerebration protocol. The first is to evaluate in which direction the scale of the "to save or not to save" is tilting, and the second is to imagine the feasibility of the "what if" the best EndoImplantology surgical protocol is applied.
Eventually, built into the presentation of the patient’s treatment plan is the possibility to modify extemporaneously the path of the plan as the treatment develops. In order to inform the patient, and to communicate the different possibilities, a classification was created for the surgical path. This will be covered in Part 2 of this 2-part article.

SUMMARY
EndoImplantology is a clinical approach which essentially blends the knowledge of endodontics, 3-D radiography, bone grafting, and implantology; the LTP is central to the decision of "saving or not saving" a tooth. Initially created as an answer to challenging endodontic retreatments, the scope of EndoImplantology was soon extended to the full spectrum of endodontic treatments. Saving the tooth remains the primary objective, while preserving the site for successful implant placement is also given consideration.


References

  1. Stroumza JH. EndoImplantology: a paradigm shift in endodontic therapy. Pract Proced Aesthet Dent. 2005;17:212-214.
  2. Stroumza JH. RSS The Ten Plagues of Endodontics at www.EndoSphere.com
  3. Stroumza JH. Rethinking endodontics: from old values to new approaches. Dent Today. November 2009.
  4. Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974;18:269-296.
  5. Schilder H. Filling root canals in three dimensions. Dent Clin North Am. November 1967:723-744.
  6. Stroumza JH. CT scans for endodontic diagnosis. Pract Proced Aesthet Dent. 2003;15:136.
  7. Stroumza JH. CT scans for endodontic diagnosis [comment]. Pract Proced Aesthet Dent. 2003;15:270.
  8. Stroumza JH. The role of diagnosis and contemporary technology on endodontic success. Endodontic Therapy. 2003;3:1-2.
  9. Adell R, Lekholm U, Rockler B, Bränemark PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg. 1981;10:387-416.
  10. Albrektsson T, Bränemark PI, Hansson HA, Lindström J. Osseointegrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man. Acta Orthop Scand. 1981;52:155-170.
  11. Stroumza JH. Treatment planning in endoimplantology: from case selection to site specific decision-making process. Dent Today. April 2010. In press.

Suggested Readings

Hoff B. The Tao of Pooh. New York, NY: Dutton Adult; 1982.
Emoto M. The Secret Life of Water. New York, NY: Atria; 2005.


Dr. Stroumza received his DDS degree from the Garancière Dental School, University of Paris VII, with emphases in endodontics, periodontics, oral surgery, and radiology. After practicing and teaching in Paris, he completed further training at UCLA and received a Masters of Science in Oral Biology, doing research in growth factors and the extraction and testing of bone morphogenic protein, discovered by Professor Urist. He then received his endodontic specialty and his Doctorate in Science for his research on human osteoblastic cell migration and the impact of endotoxins in healing of lesions of endodontic origin at Boston University. Since teaching at University of California in San Francisco, he maintains a full-time practice in San Francisco and lectures nationally and internationally. He can be reached at (415) 221-6301 (Clinic) or (415) 221-4-525 (teaching institution), e-mail at ei2doc@gmail.com, or visit his Web sites at endoimplantology.com or endosphere.com for lectures and hands-on course schedules.

 

Disclosure: All rights reserved. EndoImplantology and EndoSphere are registered United States trademarks held by Dr. Stroumza.