There is no way that we can predict if and when a voided obturation will fail. The primary reason for this is because we do not know, on a patient by patient basis, which specific bacteria predominate within a patient’s oral flora. Different pathogenic bacteria have been shown to be more or less aggressive in endodontic pathogenesis.

Endodontists are generally held to a higher level of expertise than general dentists. I keep this in mind when I judge my work. If I am able to fix something that is not ideal, and not increase risk to a patient, I do. If I feel that work that I have done is less than the standard I’d expect from a general dentist, I feel the need to correct that.

With respect to voids: I’ve mentioned previously, the more coronal the voids are, the more serious. The more voided an obturation is, in general, the more serious.

Retreatment is not seen as reducing prognosis. Retreatment that goes wrong does. Any work that we do to a tooth has the potential for misadventure — hence the need for informed consent.

If I have to repack GP in a tooth that I have very recently treated, I consider that a correction, adjustment, revision. If I have to work on a tooth that someone else has worked on, I consider that a retreatment. The why to this statement is a long topic.

A second opinion about your obturation from another general dentist carries less weight than a second opinion from an endodontist. If in doubt, improve the obturation situation if you can, or refer to a specialist for another opinion or for them to improve it.

Um..your last question. It’s easier to get a temporary filling out of a tooth than a permanent filling. The easier, the less risk of things like perforation.

Again, with the case that I’ve presented here, there are 3 reasons that I didn’t revise the obturation: Healing is obvious, voids are apical, voids in this blunderbuss apex are tricky/risky to fix. If the voids were coronal or throughout the obturation, I would have been much, much, less satisfied.

Thanks for such a detailed and interesting reply. Hurray indeed for Calcium-Hydroxide!

In general, do you find that voids are not a clinical issue? My understanding is that providing there has been sufficient disinfection and a complete apical and coronal seal achieved then while backfill voids may not be pretty they infact present very little risk of endodontic failure. Can one perhaps put a time limit on percolation? In other words can one wait and see and after a given period assume that percolation is not happening (or rather, is being blocked by sealer)?

I have in mind the situation where having been confident of ones work, closed then taken film, one finds backfill voids. Is there ever a case for going back in for reasons other than just making things look as good as possible?

What if a patient returns after taking a second opinion and requests that the voids be corrected before say, the placing of a crown.

Would you be happy to go back in or would you resist the patients request? I would be interested to know where the line is between just redoing the endo and ‘retreatment’ from a specialist point of view, given that retreatment is generally seen as significantly reducing the chances of longterm endodontic success.

I’m presuming that the correct time to consider removing the gp in order to
have another go at complete obturation, with a view to increasing chances of
longterm success, is during the initial procedure and prior to closing.
Thereafter the chances of endodontic success would be less. However, I’m
not clear on exactly why this should be. From a specialist
point of view, what is it that infact reduces the chances of success for
retreatment so dramatically and would correcting backfill voids count as
such retreatment?

Further enlightenment would be much appreciated!

The success of endodontic therapy is determined by a combination of radiographic and clinical signs. Osseous healing is a generally accepted sign that infection has been eradicated from within and about the root of a tooth.

Dentinal tubules can potentially harbour bacteria, yes. But in this case the demonstrated osseous healing provides some strong evidence that the canal system is infection free. Because calcium hydroxide has been shown to deeply disinfect dentinal tubules it is difficult to speculate that bacteria still exist in the apical root dentin of this tooth.

Because of the morphology of this canal system and thus compromised instrumentation, we also don’t know how intact a smear layer is within the canal. Smear layer is potentially a protective layer against bacterial invasion to canal space through tubules.

The possibility of future bacterial invasion of these apical dentinal tubules from the direction of the periodontal ligament is remote since there is no evidence of periradicular infection anymore. The void in obturation is apically situated and the more likely place for bacterial invasion through tubules, the cervical area, is well obturated.

From a mechanical perspective, because the apical canal space is wider than the coronal canal space, ideal obturation of this area is difficult to do predictably without blowing gutta-percha out the apex.

An obturation with voids is never considered a goal of root canal treatment since the more voids we have the more potential there is to house bacteria. In this case, however, retreating the endo to attempt correction of the apical obturation could very possibly leave the tooth in a worse state than it current is in. Any future revision of the endo would more predictably be done surgically. A more positive seal would be possible retrograde.

Here‘s another post about short fills (a short fill leaves a rather large void in the canal).

And here‘s a case of very, very short obturation in a horizontal root fracture.

The general rule for endo is that the more coronally located things like perforations or obturation voids or fractures are, the lower the prognosis.

Thanks again for the question. Ask away if you see anything else on here that you’re curious about.

I just found your interesting blog page on root therapy. I’m interested in your decision not to go back into 21 to correct the void in the obturation on account of it being less in your patients best interest and more just a case of making things ‘presentable’.

My understanding is that voids in an obturation equal endodontic failure since there will be an inevitable reinfection of the tooth by percolation from the external walls via dentinal tubules.

I’m interested to know if your experience is different to this and to what extent an obturation with voids can be considered a success or in the patients best interest.

Perhaps you’re saying that while it would have been preferable to have no voids, going back in for retreatment would reduce the chances of long-term success even more?

Thanks for the informative post – endodontic blogs are few and far between!

Vee

IMHO, no accessory point is too thin for lateral condensation as long as you use enough of them to get a solid obturation. When I do lateral, though, I use a finger spreader that corresponds to a #30 file and then use #25 size standard master cones as accessories. Master cones are less tapered than non-standard accessory cones and in my hands help with a more solid apical condensation before binding higher up and blocking me out apically. Not sure if that makes sense.

i feel like a stupid 4th year right now coz i probably misinterpreted your entire post…

in other news, i managed to completely screw up an obturation. 3 hours later my demonstrator had to finish it for me. Apparently using FF accessory points was too small. Who knew!

Short-term success, which this is, is always nice to see. Long-term success is fabulous, but takes time to ascertain. Endo cases sometimes show short term healing (especially surgeries) but can and sometimes do relapse (Strindberg 1957..year might be off a couple of years).

what’s a blunderbuss apex again?