Selective Root Retreatment

Selective Root Retreatment failure

Selective Root Retreatment of an endodontic failure

Selective root retreatment is an endodontic retreatment procedure of a failing root canal. The difference is that in selective retreatment we only treat the root(s) that shows evidence of failure.

When is it advisable to do selective root retreatment?

Typically this will be a tooth with a root canal where only one root has evidence of failing, usually a radiolucent apical lesion. Most commonly we see this when there is anatomy that the original doctor did not clean out. Therefore, an upper MB2 canal is the most likely scenario but any multi-rooted tooth can have this.

Selective Root Retreatment of an upper molar
Selective Root Retreatment case of a missed MB2. This case ultimately also experienced failure but the patient got another decade out of the tooth.

Another spot is lower molars with 2 distal canals but only one canal has treatment done.

This is a case of selective root canal retreatment where the original doctor missed one of the distal canals and separated a file in the canal as well.
This is a case of selective root canal retreatment where the original doctor missed one of the distal canals and separated a file in the canal as well. On the right you can see a very small file piece and the thermafil carrier that we took out during our retreatment.

Why do many dentists avoid doing selective retreatment?

Number one is there is not a lot known about this technique. The fact there is not a lot known about the technique means few dentists even know that this is possible. Secondly there is a stigma against it in the same way and for the same reasons as to why dentists shy away from things like the Hall technique. Dentists and humans in general have a general misconception that if we put in more work the results will naturally improve. So because things like the Hall technique and selective root retreatment are easier, they must be inferior. However, this is not necessarily the case and we should rely on the research to guide our clinical decisions.

Another reason that few do this is the procedure is do to the relationship business of endodontics. Retreats of all kinds are mostly going to be done by specialists for general dentists. A specialist may just retreat the whole tooth because they do not want their referral source thinking they are lazy or trying to take a short cut. Basically the extra time it takes to clean out the other roots is less time and risk than explaining the rational to their referrals.

Before and after of a selective endodontic retreatment of MB2 canal.
Selective endodontic retreatment of a MB root.

Research on selective root retreatment

There is not a lot of research on this technique. This is do to the fact that selective retreatment is seen as taking a short cut and few have the courage to take a stand and say this works. Again we should let the evidence decide what we do. Nudra JOE 2015 is one of the best articles on the technique.

Selective treatment of the MB root only.
Selective treatment of the MB root only on a tooth that there was no MB2 before.

What does the healing of endodontic retreatment look like?

That depends on the person. One interesting radiographic finding are fibrous scars.

Apical fibrous scarring post endodontic treatment Fibrous scars on endodontically treated teeth.


1 vs 2 steps for retreatment of a failing root canal

Toia JOE 2022 shows that healing at 18 months is equal for both methods.

Orthograde vs retrograde endodontic retreatment.

If we use a coronal access then the treatment is orthograde. Orthograde placement of medicament is what we do in a vital pulp therapy or regenerative procedure. Retrograde is the placement of the medicament through the apical region such as after an apicoectomy.

Solvents for retreatment

The most common chemicals that we use are xylene, chloroform, and orange oil. The bioceramic sealers use 20% HCl or formic acid. Rezaei JOE 2023