Endodontics is a routine part of restorative dental procedures. Many teeth presenting with large, old restorations require endodontic intervention to manage tooth pain and allow for restorability. Initial root canal therapy is very predictable and time-tested as a strategy for maintaining natural teeth in the dentition. Many restorative dentists perform their own root canal treatments. This “in-house” service is efficient for the restorative dentist and provides convenience for the patients.

When initial root canal therapy is successful, it provides patients with comfort, longevity and the ability to maintain their existing dentition. However, when pre-treated teeth present with pain, swelling and discomfort, diagnosing, treating and managing the outcome becomes a significant concern. Re-treatment of endodontically-treated teeth is challenging and complex. Successful outcomes can only occur with proper planning and collaboration of the restorative/endodontic team.

Endodontics, like other areas of dentistry, has become more advanced and sophisticated with improved technology and increased knowledge. The use of endodontic microscopes is the standard of care for routine therapy. Limited and minimal pulpal access openings are very common in order to maintain tooth structure and support. Rotary instrumentation, filling materials and techniques have advanced tremendously in recent times. And with the advent of Cone Beam Computed Tomography (CBCT), diagnosis, treatment planning and predictability are greatly enhanced. These new technologies and advances in endodontic care require the restorative dentist to develop a “collaborative mindset” and create a “team-based” approach to complex and difficult case presentations.

John West, a well-known endodontist from Tacoma, Washington, presented the importance and need for an “interdisciplinary triad” when confronted with complex, interdisciplinary concerns. This triad consists of the patient, the restorative dentist and the specialist (endodontist). The coordinated diagnosis and treatment approach must be satisfactory to all three parties in the triangle. Shared understanding, diagnostic tools and predictable, outcome-based treatment must be integrated. Successful results can only occur with application and understanding of this interdisciplinary triad. Collaboration is key!

Proper diagnosis in challenging endodontic situations is crucial for patient trust and treatment success. It is important to utilize all the tools we have available to aid in the treatment direction and treatment approach. Traditionally, patient symptoms, periapical radiographs, pulp testing, percussion and palpation were the key parameters for determining treatment approach. Today, CBCT plays an integral role in diagnostic criteria and treatment direction. Collaboration with an endodontic office utilizing this technology provides improved patient care and more predictable outcomes. This article outlines two collaborative endodontic cases in which CBCT application guided the treatment process and outcome.

Case #1: Peggy E.

gingival recession interdisciplinary treatment

Peggy presented to my office with the desire to change the appearance of her front teeth. She presented with old porcelain to metal restorations on teeth #8, 9 and 10. The margins were leaking and the combination of a high smile line and gingival recession created “black line” marginal appearance. Additionally, she did not like the diastema between the central incisors. Additional restorative dentistry was necessary in the posterior quadrants, but we will limit this presentation to the anterior teeth.

facially generated dental treatment planning

Facially Generated Treatment Planning was applied to create the plan of action and the outcome desired. Additional incisal length would improve tooth proportion and create a more positive smile line. Peggy was pleased with the appearance of her high smile line (gummy display) and had no desire to change the tissue levels. The treatment plan called for removal of the old porcelain to metal crowns. The restorative replacements would be e.max full coverage restorations on teeth #8, 9 and 10. Tooth #7 would be prepared for an e.max veneer. The cuspids would be bleached and composite restorative material would be utilized to improve the incisal edges, as needed, for functional improvement.

restorative treatment planning radiograph

The pre-treatment radiograph indicated that previous root canal therapy had been performed on teeth #9 and 10. A traumatic accident during Peggy’s childhood necessitated the endodontic therapy and subsequent anterior crowns. Tooth #10 showed a slight periapical radiolucency/enlargement. Peggy exhibited no symptoms during this diagnostic phase. It was decided that the previous crowns would be removed and provisionals placed. A re-assessment of the endodontic treatment would be performed at that time. There was also concern of the structural integrity and long-term predictability of the remaining prepared tooth. Peggy scheduled for crown removal and provisionalization.

tooth preparation provisionalization

The porcelain to metal crowns were removed and the abutments evaluated for structural integrity. The endodontic access cavities were sealed and intact. There was adequate tooth structure to proceed with the restorative process. The prepared teeth were provisionalized. Although there was adequate structural integrity for restoration, the patient was referred to the endodontist for re-treatment evaluation.

periapical radiograph

Peggy scheduled for tooth #10 re-treatment evaluation with the endodontist. The periapical radiograph indicated the radiolucency at the apex. She exhibited no symptoms since her provisionalization. Using traditional thinking and treatment approach, there would be two avenues of re-treatment for a situation such as Peggy’s. One avenue would be to open the access cavity of tooth #10 and initiate a conventional re-treatment process. The second option would be to perform an apicoectomy to attempt to retro-seal the apical aspect of tooth #10. Either process could be chosen with the expectation that an adequate seal would be achieved. The restorative process would then be initiated.

CBCT scan endodontic

As an alternative to the traditional approaches in endodontic re-treatment, application of CBCT as a diagnostic tool can significantly alter the direction of treatment. The endodontist (Ben Jafarnia D.D.S., M.S.) obtained a CBCT for the area of tooth #10. The findings revealed that re-treatment of the previous root canal could not be performed with a predictable and long-term outcome. Neither traditional option for re-treatment would be successful. Conventional re-treatment, through the incisal access cavity, would have resulted in a very over-instrumented canal to gain an adequate seal. This over-instrumentation would have rendered the structural integrity of the tooth questionable over the long term.

Performing an apicoectomy would also have resulted in a long-term questionable outcome. Due to the large previous canal filling and its buccal-lingual extent, structural integrity would be questioned. Additionally, because of the extensive periapical radiolucency, a significant amount of tooth root would require removal. The apicoectomy would result in a very short-rooted tooth with questionable mobility and longevity. Thus, following evaluation of the CBCT, the endodontist recommended tooth removal.

implant tooth prep

Peggy understood the need for tooth removal. The collaborative discussions between the restorative dentist and the endodontist created trust and confidence for her to proceed with the tooth extraction and implant placement. The provisional crown on tooth #10 was converted to a pontic attached to the provisionals on teeth #8 and 9. Peggy proceeded through the restorative process uneventfully. Tooth #10 was extracted and bone grafted. When healed, the implant was placed. Once the implant integrated, the implant post and crown were fabricated.

final e max restoration
Final e.max restorations teeth #7-10

The final restorations were placed and Peggy was very pleased. Implant tooth #10 was restored with a custom ceramo-metal post and a cemented crown. All the restorations were bonded rather than cemented. This case is now two years post-treatment and Peggy has had no issues or concerns.

Case #2- Sandy R.

pre treatment radiograph

Sandy is a long-term patient of my practice. She presented recently with percussion and biting sensitivity on tooth #3. She also noticed a swelling on her posterior palate. Conventional root canal re-treatment was performed approximately five years earlier. At that time, she exhibited similar biting and percussion sensitivity, but no palatal swelling. The radiograph from that time indicated what appeared to be a mesial-buccal radiolucency, as well as a palatal radiolucency. An endodontist performed the re-treatment. The re-treatment involved an attempt to find and obliterate a missed MB2 canal. Conventional radiography was utilized to determine file positions and lengths. Following this re-treatment process, her symptoms resolved until this present occurrence.

pre treatment periapical radiograph
Pre-treatment radiograph - 5 years earlier

The present radiograph shows another periapical radiolucency. This is consistent with her percussion and biting sensitivity. Having had this tooth re-treated less than five years earlier, she is very frustrated with the short-term outcome. Although another re-treatment could be possible to save the tooth, there is less optimism about pursuing this avenue. Tooth extraction seems inevitable and logical.

CBCT scan final restoration tooth removal
Present pre-treatment radiograph

Although she does not want to lose a tooth, Sandy is willing to pursue treatment. Her only demand is that if she loses this tooth, she would prefer not to be “toothless” during this process. Being that tooth # 3 is in the esthetic smile zone, it is important that a plan is created that will optimize the treatment process for efficiency, predictability and to properly manage the missing space. In a case such as this, it is imperative to obtain all the information possible during the pre-treatment assessment that will provide the necessary information to coach Sandy through the restorative process. Again, this is where CBCT technology can provide information and understanding that will aid in guiding the planning and execution of tooth removal and final restoration.

Ben Jafarnia D.D.S., M.S. (endodontist) was consulted for CBCT and tooth evaluation. The CBCT scan indicates a couple of important concerns. First, the red arrow indicates the palatal apical bone loss that is consistent with her symptoms and swelling. Re-treatment of this tooth would be very challenging due to the large palatal post and the extensive root canal filling. Other scan images indicate that the mesiobuccal canals are calcified and could not be instrumented. There is no predictable hope for maintaining and re-treating this tooth based upon the CBCT information.

The yellow arrow and lines indicate the position and extent of the sinus cavity. Although tooth extraction and implant placement is the planned treatment of choice, the CBCT provides a view towards the complexity of this process. From what is seen, it is obvious a sinus lift will be required to provide adequate bone thickness for implant stabilization. The outcome will be predictable, but many steps are involved in the process.

For our patient, Sandy, this CBCT information provides insight, confidence and trust in the process of extraction and implant placement. She “visually” understands the need and can have all her fears and apprehension regarding the process addressed ahead of time. Although this case is just getting underway, Sandy has confidence that it will proceed in a strategic and calculated manner. A bonded resin bridge will be fabricated and utilized to manage her missing tooth space during the process. She will not have to be concerned with a “flipper” or an “Essex” retainer. The extraction process and implant placement will be performed by the periodontist member of my specialty team. Our team expects that the process and outcome will be efficient, controlled and predictable.

outcome based dental treatment planning

The cases outlined above provide insight into the importance of a collaborative team approach to solving difficult patient situations. The combination of utilizing improved technology and a willingness to search for the best outcome for our patients renders results that are long-term and predictable. The key is understanding and implementing the interdisciplinary triad. It is the combination of the eyes of the patient, restorative dentist and the dental specialist that will lend predictability to the end result.

John West is quoted as saying: “The interdisciplinary referral process does not just happen. It requires vision, commitment, time and energy in putting the patient's needs, wants and desires ahead of our own.” John asked the question: “Is it worth it?” I say that it very much is!

Jeffrey Bonk, D.D.S., is a member of Spear Resident Faculty.

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  • Improving Diagnosis in Health Care: Cone Beam Computed Tomography in Dentistry. National Academies of Science, Engineering and Medicine. 2015.
  • “The Interdisciplinary Referral” West, J. Dentistry Today; Nov. 200