Never leave canals open, even in case of apical abscess. As soon as canal are open, pus will drain through this new channel. After irrigation and Biomechanical preparation, give local medicaments i.e. intracanal dressing and close it. I have done hundreds of RCTs and never prescribed antibiotics too.

unfortunately no reports on such cases and we rely on what is mentioned in the text books and the experience of clinicians. For me, I rarely need to leave the canals open to release the pus. In theory as soon as the tooth is opened it should start excudate. in the worst clinical scenario, if the the pus continue, we can let the patient wait up to 30 mins in the clinic so the pus keeps coming out and then we continue with proper C&S till we get pus-free canals.

I always leave them open. I started this 47 years ago because I had a practice that emphasized treating phobic patients often with IV sedation. I too learned to seal all canals with medication. I would get calls that night with people still in pain. I could go to the office and see them, but could not do sedation because I had no assistant.

It was almost impossible for them to sit and let me use local or simply reopen the tooth because of their fear and pain.

Out of necessity I stopped resealing canals after I opened and broached. This worked will with the phobic patients, so I started doing it with the normal patients. They did not like having to come back to the office at midnight in pain.

This was an issue for a small percentage of endos but it was never an issue if I left the canals open. I did this for 47 years on all the endos I did. They stayed open until the day I instrumented them and sealed with sealer and GP cones. I averaged about one canal a day. It was a big practice.

I realize this is not a double blind placebo controlled study just a very large case study of about 10,000 to 14,000 canals. I still leave them open and simply have seen very very few problems.

I am sure these responses have to do with permanent teeth. In my work as a paedontist, when we do have primary teeth with dento-alveolar abcess, we prescribe amoxycillin. The abscess regress and then we can do any appropriate treatment. We do not open and leave canals to drain for primary teeth in my practice

It is interesting as different protocols may have good results, the point is we have many discussions here:

1. Are you sure you did proper canal cleaning?

2. Good irrigation AND PROPER SHAPING is necessary to achieve better drainage,

3. Why not let open, if we are concerned of millions of bacteria on the oral environment from those some very capable of infection... and if closing the canal in the same section there is the needs for antibiotic therapy and at least two days of analgesics...

4. Let open for how long? also is a big deal, how long it would be safe... one day, two days and them reevaluation, more cleaning and going for another appointment, so this will be time consuming..

I think that those different protocols may still be evaluated in regards to what is considerate as success, no pain, no infection, no needs of antibiotic therapy and future rate of success.

Dear colleagues,

Based on the most current evidence-based literature published in peer-reviewed journals, canals should NOT be left "open to drain"! SC

To leave a tooth open is the surest way for reifection and negating all previous attempts at reducing the microbial load.

Siqueira (2003) points that the pus formed is finite in quantity and fresh production of the same will stop once the microbial load from the infected canal has been taken care of by chemo mechanical debridement. Several studies show that leaving the canal is NOT an option. One study showed that the root canals that had been unsealed at some point during the treatment, had a higher frequency of enteric bateria than in canals with an adequate seal between the appointments (Siren et al 2003)

It must also be understood that if no pus drains from the canal after slight widening of the apical foramen at the first visit, no further drainage is to be expected no matter how long the canal is kept open.

I would recommend the publication of J F Siqueira Jr DOI: 10.1046/j.1365-2591.2003.00671.x in which one segment of the publication sums up the controversy of open vs closed dressings.

Would you expect that I should have seen some if not many problems over 47 years and 10,000 to 14,000 canals.

When there was swelling or puss coming from the canal I first want to get rid of the infection. Drainage has been the gold standard for such infections. Get rid of the infection and the patiet's body has a chance to heal. By opening the canal I got patients out of pain. I did not prescribe antibiotics provided there was no swelling or I saw fluid, puss or gas escape from the opening into the pulp chamber. The canals were left open, on the average a week. The canals were then cleaned with instruments and chemical debridement. They were then all filled with sealer and gutta percha. This cleaning and sealing was all done in one appointment.

If the patient was not having pain, I would open, clean and seal in one appointment. Again this is a very uncontrolled study. It is at best a large case study. The complete lack of bad outcomes or complications over the 47 years is some indication of success.

Dr Quarnstrom,

not sure in regards of your statement: "I want to get rid of the infection"!

The only paper published to support your approach is this one:

Leaving the pulp chamber open for drainage has no effect on the complications of root canal therapy. Tjäderhane LS, Pajari UH, Ahola RH, Bäckman TK, Hietala EL, Larmas MA. Int Endod J. 1995 Mar;28(2):82-5.

You might be correct by saying that there are no contradicting papers so far. The issue is: intraoral bacterial flora does contaminate the root canal making (new flora - previously non existing) disinfection even more difficult.

Your could drain the pus also locally via incision.

Apical swelling is a sign of primary infection or persistent infection after RCT. By discharging the pus you don't get read of the infection.Broadly, you only release the pain produced by pressure and help the patient feel better. The pus is a "fluid cemetery" between the lost "heroes" of both sides of the battle, the microbes and patients immune system cells. Re-swelling means the infection is still there. Letting the canal open it will only help other bacteria from saliva, and not only, to colonize and add help to the biofilm formation. Furthermore you help the alimentary fibers to get compacted into the root canals and that might lead to foreign body reaction, when reaching the apex, (believe me this is possible in frontal teeth and large apices I also perform apical microsurgery) which was stated in several studies as a favoring factor in persistent infection. So controlling the infection is the only thing to be done. That can be done by chemo-mechanical proper treatment. There is a mountain of literature available. Leaving the canal open will only help the patient but in superficial way. The bacteria will be still showing there sharped teeth at you! :)

Never, ever leave the canal open, this only ensures re-infection. Drain the fluctuant swelling containing pus with an incision under LA immediately - first principal of surgical treatment of infection.

Pus accumulation beyond the apical foramen cannot be resolved by further intra-canal treatment. Most failures for root canal treatment to settle or resolve after cleaning/dressing are due to re-infection through the access cavity; often due to poor seal of the access cavity. This is best achieved by a minimum of 3mm of Cavit over a SMALL amount of cotton wool. IRM or GIC over the Cavit for a resistant temporary restoration.

Most advice on this post is very poor indeed. I wonder at the value of this facility on this site.

Dr. Clarkson,

Your anecdotal comments are surprising, and unfortunately they are not substantiated by any citations in peer-reviewed Endodontic journals. If you subscribe to the concept of evidence-based dentistry, you would have a very hard time finding cohort studies to substantiate the misleading claims that you are making here. SC

Dr Clarkson,

you surely do not mean what you saying don t you?

None of us can believe this statements coming from an endodontic educator,

up to date with the scientific evidence, teaching endodontics at either undergraduate or postgraduate level.... so yes, you must be joking.

...but should your statements be seriously meant than please back them up with science to prove us all worng and yourself wright!

1. A pointing abscess (swelling, pus) associated with an endodontic treatment should be surgically drained.

2. The access cavity of any tooth having endodontic treatment should be thoroughly sealed to avoid recontamination from the oral flora.

3. Can't rule out root fracture in this case.

4. Cavit reference attached.

Basta

e Buone Notte

The apical swelling after a dressing may occur after biomechanics of the canal. I find it hehelpful to open the tooth after isolation and under local anesthesia to make the patient comfortable. This allows for any gases from putrifying material in the canal to escape. Irrigate canal dry the dress the canal with appropriate dental material with calcium hydroxide paste for seven day. at the same time relieve the extruded tooth from the occlusion and put patient on antibiotic that would take care of both gram positive and gram negative antibotics. After the seven days the condition may resolve.

Seal the canal after placement of the calcium hydroxide paste

MMarques Ferreira; Dentistry Faculty of Medicine, University of Coimbra-PT

Open the canal to dreanage of the pus is a good idea, but left the canal open to the oral environement is not scientifically correct.

After irrigation and root canal preparation put a canal dressing with calcium hydroxide paste into the canal and seal the access cavity to prevent oral recontamination.

If there are fluctuant swelling, make an incision with a scapel to drain the pus.

there is always an argument going over open versus closed dressing during periapical swelling. lots of literature to support y one should not do open dressing.. biofilm formation, contamination of root canal etc etc. I follow

1) in case of weeping canal keep it open for a day specially in case of infected cyst or granuloma where pus constantly drains from the root canal space

2) if there r no contents in pulp chamber,i.e. no pulp tissue, not even necroses and canal is absolutely dry i prefer to keep it open for day, recall the patient next day do the cleaning shaping, thorough irrigation with NaOCl, saline followed by CHX and Intra canal medicament.

3) one simple rule if u file the canal closed dressing and if u dont do cleaning and shaping the open dressing can be an option

I am afraid, I accnot support the idea of leaving the tooth open for one day. Alternatively, The patient can be asked to sit in the waiting room for 30 mins or till another patient is dealt with, the the dentist can do efficient chemomechanical debridement of the root canal system followed by tight coronal seal temporization. These measures fit with the main concept and principles of rot canal treatment which is always about elimination of infection from INSIDE root canal system.

The important question is why do we leave the tooth open? Two important factors influence the flare up:

The chemo-mechanical debridement of the root canal system

The tight coronal seal between visit.

Dear Ahmad,

What is the main concern about leaving the canal open for one day? What difference is there if left open for 30 minutes while in the waiting room and leaving it open fo 24 hours and coming back the next day? Would like to understand the scientific rationale for why it is not feasible to leave the canal open for 24 hours

If we have a periapical swelling, we want to get rid of as much puss as possible. By leaving the canal opening, once you get drainage, and leave it open you will continue to give the puss an exit. If you seal the canal even if you have cleaned the canal, the puss in the soft tissues out the apex has no escape path and so it will take the more antibiotics and longer to over come the infection. When dealing with a soft tissue infection drainage is very important.

Dear doctors,

Drs. Ferreira and Steier are commenting based on peer-reviewed Endodontic journals.

Anecdotal comments have no scientific validity! SC

I have been educated differently at the university (I studied in the 1980ies): from the endodontists to not leave open any tooth, even not a highly acute one, and from the surgeons who said "ubi pus, ibi evacua" - "where [there is] pus, there evacuate [it]" (translation taken from http://en.wikipedia.org/wiki/Ubi_pus,_ibi_evacua).

My teacher for endodontics claimed that an immediate seal would be no problem - if there would be no more exudation from the periapex into the canal... which, however, could take a considerable time for irrigation and drying.

1. Scientific Background

Can anyone please give the most relevant articles which would support immediate sealing? Dr Steier refers just to one which could support leaving the tooth open, but no study was cited to prove that an immediate sealing would give better results. Instead of vague hints to "recent evidence" in this scientific discussion community on research gate we should give the literature on which we base our conviction.

And since I'm convinced that the portion of irrelevant papers also in peer-reviewed journals is much higher than the number of relevant papers, I would prefer original articles, no reviews. I would prefer comparative, prospective, randomized and blinded clinical outcome studies. And best, studies which not only refer to the pure results but also consider the costs (time, money). Studies which not only consider the "shelted situation" at a University, but also a more practical setup at emergency units, or in private practice. Are there any?

2. Practical Aspects

In a private practice, specialized in endodontics, with all those instruments available, a microscope, and with enough time, (and also being paid for the treatment adequately), and also at the university, (being paid for other reasons than for efficient treatment), it seems to be possible to treat an acute tooth until exudation stops. Can anybody tell how long this takes (min-max, mean, median), and whether there is a possibility to estimate this time individually at the start of the treatment?

Some Scenarios Where Immediate Seal Is Questionable/Difficult

On duty on the weekend, or at night, facing some 20 patients waiting for treatment, about 5 of them with acute pain, deriving from a tooth with apical periodontitis, perhaps some patients with more or less severe injuries, and having available 2 chairs...

The patient comes at 5 p.m., and your airplane to the international endo congress is scheduled at 6 p.m., and you know all colleagues within the next 500 miles have already closed their practice, or are simply incapable...

The situation of Dr. Quarnstrom, who is treating handicapped patients... or any patient who is shivering because of fear, who obviously only visits a dentist if pain is higher than fear....

Or the situation in just any "fully booked" practice...

Any recommendations in these typical scenarios? Do we talk about science alone, or are we talking about real patients with real pain in a real practice? It is one thing to head for the optimum, which scientist do naturally (me as well), but it is of no value to demand apodictically the optimum if the prerequisites can't be met in practice, or at least not always and everywhere. I had to learn it myself, and it was hard. If you are young, or badly convinced of your ideas, you tend to underrate or negate the practical limitations. Thus, is it really helpful to establish a recommendation like "Never, ever leave the canal open" which most probably can't be followed, yet accusing the vast majority (?) of dentists to treat wrong? Couldn't we come to recommendations which consider science and practice? Something like: best would be... in case of / if the situation does not allow... second best would be... as soon as possible...

3. Own Experiences - Purely Anecdotal

I always had and have a bad conscience when in the emergency treatment I left/leave a tooth open.

Initially, I tried to treat according to my just learned knowledge, and I sealed the acute endo tooth.

But then I repeatedly observed this: you open a tooth (which may have been sealed the day before even in a specialized institution, thus 100% seems to be not possible), a tooth which pinched the patient the whole night, and you get an immediate release of pain after opening the tooth, and you treat that tooth to the best knowledge you have, and seal it again, and the next day the patient is back again with the same pain as before, or even worse, now with an abscess which is to be incised, unfortunately near the mental foramen, or which is in a location where you need a general anesthesia, or which is endangering the patients life (abscess in mediastinum, sinus cavernosus thrombolisation) - then you start asking yourself if it is just your insufficiency which is sentencing the patient to another nightmare. And whatever the reason may be, personal incapability or the bare situation: you ask yourself if this option is justifiable, and somewhen you just leave the tooth open, and the patient comes back the next day just to thank you...

4. Conclusion

From a scientific endodontic view it may be important to seal a tooth immediately. (Supposed the supporting articles are of enough quality).

But we should consider that we are talking about a tooth, a tooth to which still a person is attached. A person which suffers from pain*. A person which suffers from antibiotics* (also consider the risk of opportunistic fungal colonisation/infection and antifungal treatment, and also sensibilisation, resistancy), from pain killers* (which do have potential for severe complications), even from alcohol*(misused due to pain, and in combination with the other medicaments) , from incisions* (and possible complications like nerve damage), from anesthesia* (possible toxic or allergic reactions), and driving to the practice for (emergency) treament*(risk of accidents, pollution of air). (*I suppose a higher number / amount of these medicaments/treatments/activities in case of immediately sealing at least in emergency situations). Of course these factors are also relevant the other way round: supposed that more teeth are lost when left open... I'm quite interested in the articles, but I fear they answer just some small parts of the whole).

And from a practical view it must also be cleared how the goal, defined by science, can be achieved, if ever, and to which costs.

It is rich to read these discussions. We do not have this challenge with primary teeth. I have not had to deal with a decision about leaving a tooth with dentoalveolar abcess open in paedo. I do not touch such tooth - prescribe antibiotics and the child comes back well enough for you to progress with enodontic therapy. I agree with the need to generate levels of evidence for practices. What evidence is there that leaving a tooth open for a day or two makes the patient worse off?

Dr Pohl,

thank you for your comment and the differentiation between clinical and evidence base dentistry. This differentiation is correct and deserves attention.

The clinician indeed has to fulfill the duty of care to provide the patient with a treatment plan after consideration of all criteria. Yes, the legal aspect has a high value as well as the treatment decision has to be a shared treatment decision.

The level of knowledge, skills, technology and time available could influence the treatment making protocol. A general practitionor in an envirnment as described by yourself may build different treatment protocols when compared to a specialist endodontist. Would like to draw again your attention toward the Cochrane systematic review which could not find any healing difference between single and multiple session endodontics except for pain and possible flare up.

It can be concluded that the factor practitioner (general or specialist) dealing with the case will influence dramatically the treatment procedure and possibley the outcome.

Hello  Yango, the way you write is not only sharp and acute, it is amazing, I think that if you have spare time you should think about writing novels. 

*flush*

I have recently finished a survey study regarding this hot topic and tried to cover most of the aspects discussed here

Who told you that science can not be fun?

Dr. Steier & others

Almost 10 years from the time this question was asked, I wonder if anyone can now list for us here any recent reference(s) that support a clear solid protocol?!! Liviu Steier Stephen Cohen