This is the first in a series of examples of the different presentations that can occur surrounding the restoration of discolored endodontically treated teeth. This series will include examples I used in a previous Spear TALK (our online discussion forum) post, but some additional cases as well.

Case 1: A discolored endodontically treated lateral incisor

When considering how to treat these cases, the first thing I look for is the presence of a post or an indirect restoration. This would mean that most likely the tooth has had some tooth preparation done. In this lateral incisor there is not a post or any indirect restoration, only the composite to seal the access (Figure 1).

endodontically treated teeth Figure 1

In addition the radiograph shows a successful result from the endodontics that was performed years earlier. It also does show that the access itself is quite large, meaning that any tooth preparation could end up with extremely thin walls (Figure 2).

endodontically treated teeth Figure 2

Given these conditions the decision was made to utilize internal bleaching and no restorations to correct the discoloration. The key to the safety of internal bleaching is the placement of a seal slightly above the periodontal attachment to prevent the bleach from penetrating down the canal or into the periodontal attachment. If this precaution is not taken the literature reports root resorption rates varying from 1 to 13% (Figure 3).

endodontically treated teeth Figure 3

The typical products used for internal bleaching are sodium perborate, carbamide peroxide, and up to 35% hydrogen peroxide. The recommendations today are to not heat the bleach as it creates additional risks for resorption. Instead I generally use a walking bleach for three to four weeks, although it may require repeating from one to three times to reach maximum effect. Avoiding heat and strong bleaching agents may be especially important in teeth with thin remaining walls.

In this patient a walking bleach of sodium perborate was used for four weeks to achieve the result seen here (Figures 4 and 5). The bleach was sealed in the chamber with IRM during the four-week period.

endodontically treated teeth Figure 4
endodontically treated teeth Figure 5

Risk of reoccurrence of the discoloration varies dramatically in the literature, but can be as high as 50 percent by five to 10 years in some studies, meaning that the need to redo the bleaching is reasonably high. Nevertheless, in a tooth such as this one with no restorations other then the access cavity, and a very large access with thin walls, I believe re-bleaching over time represents a better choice then prepping and restoration.


Comments

Douglas Lee
February 14th, 2014
If gutta percha is sealed , what's the harm in using heated instrument?
Carl Crutchfield
February 15th, 2014
As I understand it, you seal at the level of the CEJ to prevent extrusion of the bleaching agent through the microporosities and accessory canals into the PDL. It is not the apical leakage that is the primary concern here.
Hannah Ehrenreich
February 18th, 2014
The tooth appears to have a fracture line running diagonally on the facial surface. Would it be better in this case to place a crown and post (if necessary to hold the core) to prevent further fracturing and risk losing the tooth?
Katy Wright
March 13th, 2014
In response to comment 1. There is no indication for using an heated instrument. I'd have to do a lit review to give you authors, but 1-2 weeks of Sodium Perborate gives an excellent result. I believe that adding heat increases the risk of cells in the PDL converting to clastic cells that may result in extracanal cervical resorption. The risk of resorption is greatly increased when the bleaching agent travels along the dentinal tubules apical to the CEJ. Comment 3. Yes, it is unfortunate that the provider who did the NSRCT created such a huge access and removed so much tooth structure but placing a post would not prevent further fracturing. Even a post with a similar modulus of elasticity to dentin (glass fiber) would only stabilize the core.
Matt Mauck
April 4th, 2014
After you achieved the color you desired what did you use to seal the tooth? You stated you will have to re-bleach in the future?
Myla Villanueva
May 26th, 2014
It is mentioned that it is important to place a seal to prevent bleach penetrating down into the canal. Any recommendations on the seal?
Allyson Monferdini
June 18th, 2014
I use a glass ionomer for the seal when internally bleaching the tooth
Dr. Ilta
February 20th, 2015
What if the tooth would present additional restoration? What would be your treatment of choice? I have a patient with nearly the exact same tooth, but it has old restoration mesially. Should i choose Zirconia Crown, Emax or Porcelain Veneers?
Daniel C.
April 11th, 2016
If there is only a thin shell of enamel left , would you choose to restore it with composite? But as you mentioned that the relapse is as high as 50% , would this make it very difficult to redo internal bleaching since you have to grind out all composite from the inside?
Scot M.
April 11th, 2016
Nice job with this tooth. My concern like others is the wide access opening in this tooth and very thin facial enamel. Depending on the pt's occlusal habits and occlusion. Is a glass ionmer or even resin enough to keep this tooth from fracturing at the gingival margin? What would be the treatment plan- if it fractures below the avelolar crest? Is that risk worth not putting in some kind of fiber post and resin core for the sake of maybe having to bleach at future date? For me - the risk is to high.