CPD Dental Files: Defining endodontic success

This article was first published in ADA's News Bulletin, April 2023.

In this recent episode of the Dental Files podcast (Ep. 44, 2022), Professor Ove Peters shares some insight into what constitutes ‘success’ in endodontics. For patients, there can be a discrepancy between patient and practitioner goals, in endodontic therapy. Shared here in written form, the podcast features Professor Peters’ expertise on this subject, as interviewed by Dr David Argent. He recommends tailoring treatment to individual patients and discusses the possibility of vital pulp therapy as an alternative to full endodontic treatment in some cases.

Dr David Argent

Well, Professor Peters, welcome back to the dental files. And thank you for a very interesting and wide- ranging lecture today. You begin your talk about what constitutes success in endodontics. Patients, I suppose judge this by how painful it was, what it costs them, and how long it’s likely to last. But as dentists, how should we judge the success of endodontic treatment?

Prof. Ove Peters *

Yeah, thank you for that question. Of course, this is if not the central question, a very important question when we start out deciding on our therapy. Essentially the therapy has to work towards the goal, and if we don’t know exactly what the goal is, how can we pick the right therapy. The move overall, is clearly towards what’s called a patient-centred or patient-reported outcome. And what we think the right outcome is may not be in any way, shape, or form, what the patients desire. You mentioned already several of the things that the patients report, at least in my experience, it’s exactly what you just listed. Now, in endodontics, we have always felt that achieving apical healing bone fill was the Holy Grail. But that was looked at simply because that’s the tool we had, by periapical films. Now in the age of cone beam computed tomography, it turns out what we thought was perfectly healed, in many cases, isn’t. So maybe this is not a very effective outcome measure. In fact, it may be the wrong outcome measure. Let me just add one more thing to that. We’re working in the European endo society towards an overarching system as to recommend treatment modalities. The first step there was also to define the outcome goals that we were looking for. Number one outcome is tooth survival, tooth retention in this particular initiative.

Dr David Argent

So why do endodontic treatments fail? Now that we can measure our success or otherwise with cone beam, what’s the primary reason that they don’t last?

Prof. Ove Peters

See that’s another very good point: when you say they don’t last, we are already predicating the failure on extraction or loss of tooth or non-survival. Really, all studies that have been written about this that actually, among treatable apical pathosis, persistent inflammation is not the main reason that teeth are lost or extracted. There’s a fracture and a very important reason for extraction, and non-restorable caries that make up probably 50% of all reasons for extraction. When you look back at, for instance, in an oral surgery setting, at the actual described reasons that the clinician mentioned.

Dr David Argent

If we look at a periapical film, and we see a periapical radiolucent area, can the patient basically be told, ‘Oh, well, we’ll just monitor that or ignore that’?

Prof. Ove Peters

That’s the multimillion-dollar question to be frank. The answer is not quite as simple as to say yes or no. There is disease, there’s no way around it. We have to qualify this a little bit. What would you say to a patient that is 95 years old, and has had this periapical change already for 25 years with no change? Why would you intervene, as opposed to a 25-year-old that has had a recent root canal treatment maybe four years ago, because that’s the cut-off when we decided ultimately it will not heal, but they have a whole life ahead of them. A lot of restoration changes and other situations will change the conditions, the ecology, for this periapical situation that is maybe at this point in equilibrium – but may not be that anymore in 10 years, when a new restoration is being planned.

Dr David Argent

So a situation which is in equilibrium, and if there is no intervention, do we have any data on what the risk is of a catastrophic flare up?

Prof. Ove Peters

Yes, we do. Not necessarily catastrophic, but even minor painful episodes. I’m not talking about an abcess or anything like that. The study that I always use is actually an Australian study quite a number of years ago, where they observed cases of observed patients over many years up to 20 years and determined that the risk of a flare-up is 5%. It depends if you are one of the five of 100 that experienced that, or the 95 that don’t experience a flare-up, if you think this is a high or low risk. We know this from all the studies also, that the risk is actually fairly low.

Dr David Argent

As dentists, we’re taught to try and avoid the pulp at all costs – we don’t want to expose it – but today you spoke at length about being less afraid of that, and maybe not, therefore having to commit to root canal treatment, but pulp capping measures. Can you talk about that, please?

Prof. Ove Peters

I wouldn’t necessarily say pulp capping. Pulp capping and direct pulp cap is a technical, relatively diffcult procedure when you want to do it really well. But when you look at the broader sense of vital pulp therapy, the technology–specifically the cements that we can apply now, and these are custom silicate cements that are provided by a number of different companies and are so biocompatible – the clinical procedures, the steps that we need to undertake are so predictable. The literature is pretty clear in the last five years that, for instance, in a permanent molar that has mature root formation, even with clinical diagnosis of irreversible pulpitis, a pulp chamber pulpotomy (I’m not talking about a pulp capping) a pulp chamber pulpotomy has an extremely high success rate: 85-95%. 

This means no need for an intervention, no symptoms. So that is on par with root canal treatment in the best-case scenario, and it saves the patient first of all going through root canal treatment, and also saves the need for a larger coronal preparation that would be required for an axis cavity. So from a overall health standpoint for the patient there’s a lot of benefit to that.

Dr David Argent

So what are the case selection criteria for vital pulp therapy?

Prof. Ove Peters

At this point, even though the literature would indicate that even irreversible pulpitis would not be a contraindication. If somebody wants to start going in that direction, they should take a look at a couple of things: Number one, of course – we don’t want any obvious periapical changes. We all know in a molar, one root canal may be necrotic as opposed to maybe the distal or the palatal canal that still has viable tissue and responds in that sense also normally to a cold test. So we have to expose a radiograph and understand what the apical conditions are. And the other point that I want to make is, if we are actually selecting a case, the best scenario to do is to directly observe the pulp, making sure that we have hemostasis achievable in two to five minutes, but can also look at the pulp stumps as they emerge out of the canal orifices.

Dr David Argent

What degree of magnification would be required to do that?

Prof. Ove Peters

I don’t think there’s an absolute, stringent number. We recommend in the current guidelines, the use of a microscope, but of course not everybody has a microscope. So I would suggest that maybe a 3.5 magnification loop would also be appropriate to observe the pulp in the access cavity. But this is my personal opinion that’s not necessarily published or based on any type of exact science.

Dr David Argent

Well, Professor Peters, thank you very much for your time. And again, thank you for your wonderful lecture today.

Prof. Ove Peters

It was a pleasure.

This transcript has been edited by its contributors for clarity. The Dental Files is a member service of the Australian Dental Association available through the ADA's CPD Portal. All opinions included in the program are exclusively those of the interviewers and their guests, and are not intended as an endorsement by the ADA, any product procedure or service.

* Dr Ove Peters is the discipline lead and Professor of Endodontics, as well as the postgraduate course coordinator at the University of Queensland’s School of Dentistry. One of the speakers to present at this year’s FDI World Congress, he has previously held faculty positions in Germany, Switzerland, and the USA. As a prolific researcher and author, Dr Peters has looked for the underlying fundamentals behind good clinical decision- making in endodontics.