The Finishing Touches: Best Practices for Finishing and Restoring Endodontically Treated Teeth

By alimyakubov / stock.adobe.com

It goes without saying that endodontists have traditionally been focused on the endodontic technique side of things, rather than restorative processes. But restoring endodontically treated teeth goes beyond a root canal procedure: For an endodontically treated tooth to be a success, the restoration has to succeed as well. This means turning focus away from solely obturation, instrumentation, and endo technique to also considering the restoration that comes after treatment. 

This emerging philosophy has been supported by The American Association of Endodontists (AAE). In a 2020 AAE publication, Richard S. Schwartz DDS, discussed the correlation between endodontic and restorative procedures, and stated that the link was critical.

“When looking at long-term outcomes, endodontic and restorative treatments are inseparable,” Dr Schwartz writes. “Endodontic procedures, and how they are performed, have considerable effect on the success and failure of the restorative treatment. Similarly, the restorative treatment affects the long-term outcome of the endodontics.”²

This becomes exceptionally noteworthy when it is considered that, despite the advances in instrumentation, disinfection and isolation, and obturation over the past several decades, the success rate for endodontic procedures hasn’t significantly improved.¹ As clinicians search for a way to improve endodontic outcomes, a new focus on the restorative side of endo treatment, has emerged—particularly centered around the importance of immediate permanent-restoration placement.² 

“Looking at the endodontic prognosis literature, time and again we see that one of the single most important factors in survival of the tooth following endodontics is definitive restoration in a timely fashion,” says Rebekah Lucier Pryles, DMD, an endodontist in White River Junction, Vermont and cofounder of Pulp Nonfiction Endodontics. “For anterior teeth, this may mean only the placement of a nicely adapted intracoronal restoration, and for posterior teeth this often means occlusal coverage.”

While they are many factors outside of a clinician’s control that can affect the success of a restoration—for instance, a patient’s physiology or compliance—one thing clinicians can manage is the quality of the initial restoration. High-quality immediate restoration is an important factor in restoration longevity, and, as Dr Schwartz writes, “even teeth with poorly fitting crowns are likely to last a long time with high-quality endodontics and foundational restorative treatment.”² 

Richard Mounce, DDS, an endodontist practicing in Pacific City, Oregon, concurs, and also emphasizes the importance of a good coronal seal, which can make or break a restoration’s success. A major cause of endodontic failure, coronal leakage opens the door for bacterial penetration, in even the most well-obturated canal.

“Success in endodontics is directly correlated with coronal seal,” says Dr Mounce. “If the case is completed, a buildup or coronal restoration should be placed immediately while the tooth is still under the rubber dam. Failure is directly correlated with not placing such a restoration immediately.”

In addition to not placing an immediate restoration, material selection can have a large effect on clinical outcomes. The decision to go with a post-and-core buildup over a direct restoration can also play a big role in procedural success. Factors such as remaining tooth structure, the ability to close endodontic access with a direct composite, and the ability to achieve full coronal coverage can affect a clinician’s decision.

While the temptation may be to go more conservative with a direct restorative procedure, the predictability of these restorations has come under critique. Researchers recently found that coronal coverage greatly impacts the survival rate of endodontically treated teeth—so much so in fact, that tooth loss was 6 times higher in cases without coronal coverage.³ This means many clinicians are turning to crowns as a solution. 

“With rare exception, all endodontically treated teeth should be restored with crowns,” Dr Mounce says. “Virgin anterior teeth with conservative access cavities might be the exception but this scenario is uncommon. The crown design does not need to be different from any other non-endodontically treated tooth which is being crowned.”

This doesn’t necessarily mean that a post-and-core buildup is always the right course. The amount of remaining hard tooth structure should be considered before diving directly into indirect restorations. Direct restorative procedures can be less invasive, and more inexpensive for the patient. Preserving as much dentin and tooth structure as possible can increase the likelihood of restoration success. Clinicians must take into account existing periodontal disease, location (anterior versus posterior), and occlusion when deciding on a direct restorative plan. In anterior teeth, clinicians may be more inclined to consider composite restorations, as placing composite below the cement-enamel bond level can provide a good coronal seal (to reduce the risk of bacterial transmission) and also reduce a tooth’s risk of fracture.⁴ However, when it comes to posterior restorations, clinicians should consider other options 

While the debate rages about the best method of restoring an endodontically treated tooth, once a post, core, and crown treatment has been decided upon, being able to produce a high-quality restoration increases the life of the tooth.

Regardless of restoration type, in either approach it is critical to preserve as much dentin as possible while ensuring that all decay and caries are removed. In fact, the primary cause of extraction of endodontically treated teeth is not endodontic failure, but failures in restorations and caries removal, and subsequent periodontal disease.⁵ Emerging minimally invasive techniques are streamlining the process, which will only become easier in the future as these technologies continue to develop. One such advancement comes in the form of cone beam computed topography (CBCT) which has allowed clinicians with imaging to simplify treatment. Other developments, such as dynamic guidance, are also helping to streamline endodontic procedures. In time, these advances will hopefully help simplify endodontic treatment, making the finishing and restoration of endodontically treated teeth an easy process with fewer difficult decisions.

References

1. Bartols A, Bormann C, Werner L, Schienle M, Walther W, Dörfer CE. A retrospective assessment of different endodontic treatment protocols. PeerJ. 2020;

2. AAE. Endodontics: Colleagues for Excellence. Colleagues for Excellence A New Look at the Endo-Restorative Interface. Am Assoc Endodontists. 2020.

3. Aquilino SA, Caplan DJ. Relationship between crown placement and the survival of endodontically treated teeth. J Prosthet Dent. 2002;87(3):256-263.

4. Dental amalgam: Update on safety concerns. ADA council on scientific affairs. J Am Dent Assoc 1998; 129: 494–503.

5. Baba, N, White, S, Bogen, G. Restoration of Endodontically Treated Teeth. Restoration of Endodontically Treated Teeth. Endodontic Prognosis. 2017; 161-192.