As the patient is young, my opinion is to save the tooth, so i would suggest RCT and further apicectomy with retrograde filling. However the mobility of the tooth has to be taken into consideration.

I would try endodontics in the first place. Good hygiene and infection control protocol and a conventional root canal filling. X-ray control 6 months later (if possible with the same exposure geometry as final x-ray afte endo) to see whether radiolucency deceases in size. If not, consider apicotomy or better, apical currettage.

Reconstruction with glass-fibre post and composite as semi-permanent solution till patient is old enough for crown.

I meant "decreases in size"sorry for the typo

I would try my best to keep the tooth, but how is the patient’s hygiene? Nutritional habits? Motivation? I would weigh-in all the facts before choosing a treatment course.

- In my opinion, if the patient can attend multiple visits, you can try calcium hydroxide for few weeks to 2 months, and the cyst can heal without surgery/retrograde filling. This has been reported by Caliskan (2004), and with my experience, it is a conservative and reasonable ttt option, providing that you are able to maintain an optimum coronal seal throughout the ttt.

- If the patient can not attend many visits/you don't have the time, then if an adequate obturation can be achieved, you can do root end resection with no need for a retrograde filling. I believe that retrograde filling is only required when you are not able to perform an adequate mechanical instrumentation/obturation of the apical portion of the canal I have published a similar case.

http://www.jcd.org.in/article.asp?issn=0972-0707;year=2012;volume=15;issue=1;spage=77;epage=79;aulast=Ahmed

I hope this could help!

i would go for the calcium hydroxide treatment as mentioned above followed by a proper rct and obturation of the rt. since this is a young patient, i would want to keep the tooth at least until skeletal growth completion.following this, my choice of treatment would be an implant retained prosthesis.

A good rct is usually adequate for these cases. complete bone healing is evident in the follow-up months. even if this cyst does not heal entirely, it will deminish in size thus making future implant treatment less complicated.

The indications for apicectomy have reduced as our ability to fully obturate the canal has become better.

hope this helped.

hi everybody, thanks all for your interest. it was so helpful for me. i decided to go for conventional RC ttt, irrigation several visit with chlorohexidine, until i confirm good cleaning and shaping, no more pus oozing. then i go to Ca hydroxide for nearly 2 weeks (as shown in x-ray, i am now in this step). then i will go for obturation and follow up after 1, 3, and 6 month to observe the cyst size. according to that i will take my decision to apicectomy or not.

the problem i think for Ca hydroxide is that it can not provide me good apical sealing, this is a huge problem i supposed.

anyway, i will continue and see. thanks again all :)

This is the case from occlusal view

Hi Hanan,

- Do not worry regarding the extruded calcium hydroxide. It would exert some antimicrobial activity on the external root surface, and it may help to eliminate the cholesterol clefts that may impair the healing of the cyst like lesion. Usually calcium hydroxide is resorbed after some time. My worries are more on the coronal seal, that should be maintained adequately throughout the ttt..

- During irrigation, please take care not to combine NaOCl and CHX. They may produce a toxic precipitate.

Good luck!

You can try with three mix or antibacterial mix for infection of root canal ,it will surely work

by radiography appears to be a cyst and is displacing the root of the central incisor. would root canal treatment, and surgery to remove the major quiste.Es duct sealing. Wait a while for the reconstruction.

As the patient is young so its better to save the tooth by root canal treatment , apicectomy with retrograde filling.

Probably a retrograde filling with MTA will offer better results.

My point of view is very clear. Endodontic therapy is the best option for this young patient. Obviously, the purpose is to treat this tooth but also to obtain a bone healing process in order to facilitate an eventual implant therapy in the future when the bone growth will be achived. Concerning the technical aspects, in this kind of cases, we often have to combine differents technics depending on the operative conditions (can the canal be dried or not for exemple ? is there an apical resorption ?). A cone beam could be required to evaluate the volume of the lesion and especially its palatal extension.

Tatini Claudia

thanks so much for your opinion,,, i just want to ask about the percentage of sodium hypochlorite , u mention a percentage of ( 5-6% ) ... is this percentage high or it is ok ?

could u please tell me more about istologic exam ??

thanks again :)

Concerning the concentration of NaOCl, the recommended range is between 1% and 5.25%. Increase the percentage leads to a better solving ability on organic tissues but also to an high toxicity in case of apical extrusion. An intermediate choice (2.5%) seems to be the good option.

Famous author like Zehnder M (Zehnder M. Root canal irrigants. J Endod 2006;32:389–98) suggested 1% NaOCl could be sufficient. However 0.5 % (Dakin) hos not enough solving ability on organic soft tissue even if the antibacterial properties are interesting. Having said that, i agree with claudia and 2.6 % seems to be the best compromise. Finally, even if the NaOCl concentration is a matter of debate and has a clinical relevance, this later should be chosen according to other factors (type of root canal preparation, volume of irrigant, temperature of irrigant, viscosity and surface tension, agitation technique...). Moreover, fresh hypochlorite is used continuously that likely decrease the impact of the concentration. You can find the publication i mentioned in the attachment file.

Agreed and couldnt agree more on the use of rubber dam isolation. Hypochlorite, especially the more concentrated one, can cause ugly ulcers.

Hello all, 14y.o , a young patient with good potential healing. Of course endodontic treatment if the first choice and should be performed under rubber dam, to isolate the tooth from additional oral contamination, and prevent the toxic effect of NaOCl on oral tissues. Several reports exist on the dangerous effect of NaOCl, either because of apical extrusion (with various NaOCl concentrations) or after contact with tissues (toxic effect or allergy). Cone beam could be used to evaluate the 3D lesion extension. Biologically, apical resorption (even if it could not be seen with a retroalveolar radiograph) is generally associated to bone lesion of endodontic origin.

I think it is better in such cases, to irrigate with something like ( chlorhexidine )

Hanan Nabil, i would like to know why you advocate to use Chlorhexidine in this clinical case ? Even if you choose to use it, it's compulsory to irrigate with NaOCl which has solving ability on necrotic organic tissues. The only advantage of Chlorhexidine is the remanence of antiseptic effect. Use chlorhexidine in Endodontics is alos a matter of debate. You can use chlorhexinine for a final flush after EDTA but i can'treally see the advange hire (initial therapy, young patient...) in comparison to NaOCL.

Frédéric Bukiet ... sorry for being late for answering u :)

i think, the problem here in such cases is pushing the irrigant solution ( NaOCl) into the periapical tissues

so, i was just afraid from using NaOCl in open-apex cases .

Seems to be my fate to give again the advocatus diaboli - or perhaps even a real opponent.

There are several reports here upon the toxicity of NaOCl, upon ugly ulcers, and in this case it shall be used in a young patient, but nevertheless the conventional endodontic therapy is "of course" the first choice.

Furthermore, the penetration depth of NaOCl into the dentinal tubules is limited to some tenth of a millimeter.

Thus, there must be some tremendous advantages of this therapy that it is recommended without any doubt or hesitation.

Which are these? Is it just the surgical intervention as itself? Or, are there other advantages? Duration of treatment? Number of appointments? Number of radiographs necessary? Total costs?

Are there better healing results? Less flare-ups?

Or is it the bias which derives from the own education, from the individual specialization?

Just to remind us to then and when have a look over the rim of the tea cup, and that I like these interdisziplinary discussions here. I already learned a lot. And indeed, I will have to think about the choice I would draw in this case.... One question is: Is NaOCl suspected to have long-term adversal effects? I just opened a new question since the title here is misleading...

Yango Pohl.... thanks for sharing your opinion :)

i will search more about the ( long-term adversal effect of NaOCl )

anyway, i really do not like NaOCl ,, one day, patient tell me while i use it as irrigant ( oh, doctor i smell chlore ,,, are u use it ?? and i get panic ,, then i told here the truth :)

my patients hate it so much :)

Using an excellent aseptic and antiseptic conditions the prognosis is somewhat positive. However, a sytematic follow up is recommended after 4 months and is the picture fo the lesion reduces after one year you could explain your patient the outcome of the treatment

Hi Gérard,

A big pleasure to meet you on researchgate.

Hanan Nabil,

well, here in Germany we also don't like the smell of Chlore, but nevertheless it is widely used (pools, disinfectants for making your home "clinically clean"), and therefore people are used to it. At least no one complaint about it as far as I remember my patients.

Are there reasons that people in your country complain when chlore is used in the dental office? Is it that unusual? Or are you better informed about potential risks? Is there a difference in the smell sensorium?

It seems from your report that the rejection is that strong that it influences therapy (which should be considered if studies shall be compared or guidelines be established)...

Hi Hanan and Yango Pohl,

Actually I remember that I have the same comment from one of my patients!, but usually at lower concentrations (2.5 and below), the patient will not recognize the smell, unless you are preparing the dilution in front of the patient!!!. Indeed, the patient psychology should be highly considered, but at the same time, the role of NaOCl in endodontics should never be undermined.

Dear Hany,

as a scientist, and that is my deepest conviction, it is our duty to question every day what we are doing, if it could be improved, or replaced.

In case of NaOCl this irrigant is definitely damaging vital tissues, it is definitely toxic. Thus there must be unique advantages which produce clearly better results than other techniques or methods, to justify the use of this definitely toxic product.

The smell is just one point, but we should be aware that a bad smell is normally a clear sign for us to stay away, a sign for severe danger for our health and life. The smell is a much older sensorium than our eyes, our ears, it carries the experience of hundreds of millions of years of life onthis earth. Unfortunately not every danger can be "smelled", but if it is smelled, you can be quite sure that the danger is there.

I was not aware of this toxic potential of NaOCl. I'm just reading some papers and books on this problem. And there are some terrible outcomes of the use of this irrigant. Maybe they are rare compared to the huge number of endo treatments where it is used, maybe we have to accept them as "collateral damage", as a kind of "damage due to friendly fire", but as long as there are so few comparative clinical studies which doubtlessly prove the advantage of this irrigant (are there any?), the use of NaOCl has to be questionned. And even if the whole world of dentistry supports this irrigant, it would not be the first medicament which was widely used, and then was considered fatal somewhat later.

In this context, I hope that your last sentence is not a basic statement that the use of NaOCl is forever justified and holy, but only reflects your opinion that the patients psychology is very important but we should not throw away our medical knowledge because the patient has a different opinion or conviction.

RCT then follow up.

For NaoCl, Ithink that fighting smell of offensive pus by offensive but cleansing odour of NaOCl.

Dear Yango,

Vielen Dank for your kind reply and explanation (by the way I know some Deutsch!, and Germany is one of my favorite countries). As you said, the terrible outcomes are very few to the huge number of endo treatments, and I believe that adjusting the concentration of NaOCl is an easier approach to solve these toxic effects rather than searching for another irrigant that should be cheap/available/etc...., especially that many studies demonstrated the ability of NaOCl to maintain reasonable antimicrobial and tissue dissolving effects at lower concentrations.

In addition, many times the toxic effects of NaOCl are caused by inappropriate use of the needle rather than the irrigant per se.

In my opinion, adjusting the conc. of NaOCl according to each case (open apex/external root resorption/proximity to maxillary sinus/mandibular canal) and meticulous use of the needle would prevent/minimize the occasion of this toxic potential. But indeed, any other alternatives that would have similar properties especially low cost and availability are most welcomed.

Dear Hany,

thank you for your reply. And thank you for your German words. Unfortunately I can't answer in your language.

Yes, maybe, the reduction of a concentration of a substance may diminish the toxicity. Is it non-toxic then? And - is it then still working? If I refer to that study from Tibet where they found not worse outcome, but less complications when using saline instead of NaOCl, then at the latest we need a discussion. Yes, there are numerous studies that NaOCl can dissolve tissues. But - if that is clinically irrelevant? When there is not any advantage? Saline, if the study is right, offers the same - but at lower costs, lower toxicity. With NaOCl they had 10% complications, with saline 2%...

And whether the toxic effects derive from wrong usage or not: that is irrelevant as long as you can't show that a special education (costs!) can minimize these risks. (and you manage to limit the endo treatment to those specially trained colleagues..). For the patient, it is not important, whether the material is damaging, or the improper use is the deeper reason for his problems. If it can be used in a wrong way, it will be used in that wrong way...

And as far as I understand Hülsmann/Schäfer in their book "Probleme in der Endodontie" (Problems in Endodontics) you can only expect a dissolving effect at the most apical part of the root if you press the irrigant beyond the apex (which is logical). But this shall be avoided in every instance. For me, this seems to be like a systematic fault...

And now? How much can this concentration be lowered without loosing the dissolving effect? I am sorry, I see more questions than answers with this material...

The NaOCl concentration is still a matter of debate. There is no consensus. The advocated range is between 1 and 5.25%. The toxicity and the solving ability obviously increase according to NaOCl concentration. However, the antibacterial efficiency and a sufficient proteolytic activity can be conserved with low concentrations (between 1 and 2.5%) if the renewal and the agitation of the irrigant is well carried out. From my point of view, NaOCl extrusion can trigger very serious consequences but this kind of problem is rare if the practionner takes care and manage carefully his clinical case. Finally, i'm in full agreement with Hany even if i respect Yango's way of thinking. Basically, i think all the aspects and products of our dental treatments may have bad consequences if the practionner has not the knowledge and the necessary skills.

Many thanks Yango for your kind reply, and I am really happy to share with you and Frederic this valuable discussion.

- The optimal concentration of NaOCl that would maintain all the desirable properties and minimize potential risks is controversial.

Despite this controversy, there are some clues that would help us for selecting a reasonable concentration of NaOCl.

1) Concentration/tissue dissolving effect

Clarkson et al. 2006. "Dissolution of porcine incisor pulps in sodium hypochlorite

solutions of varying compositions and concentrations".

1 and 4% NaOCl resulted in pulp dissolution after 38 and 12 mins, respectively.

2) Concentration/antimicrobial effect.

Depends on many factors time/direct contact/microbial virulence/biofilm (Luddin and Ahmed 2013).

3) Concentration/toxic effect

Surrounding vital structures/ open apex. 0.5 to 1.5% is preferred.

In conclusion: Complex root canal morphology, microbial virulence, and limitations of NaOCl continue to be a great endodontic challenge. However, I believe that NaOCl is like a bell curve chart in which 0.5 and 6% are in both extremes and rarely used. Other concentrations are more common (1-2.5%) and the operator should judge each case separately, based on the literature and his ability to handle this irrigant.

- I believe that saline has few indications in endodontics, and many authors reported that saline is not a suitable root canal irrigant,especially if it is used alone, as it lacks the tissue dissolving effect and has no/limited antimicrobial activity, as mentioned in the references below

- Zehnder M (2006) Root canal irrigants. Journal of Endodontics 32, 389-98.

- Schäfer E (2007) Irrigation of the root canal. ENDO - Endodontic Practice Today 1, 11-27.

- Hülsmann M, Rödig T, Nordmeyer S (2009) Complications during root canal irrigation. Endodontic Topics 16, 27-63.

- Haapasalo H, Shen Y, Qian W, Gao Y (2010) Irrigation in endodontics. Dental Clinics of North America 54, 291-312.

- I also have a couple of publications if you want any.

Dear Frédéric, dear Hany,

I think the real problem is that we use different success criteria.

From a technical standpoint, you are right, yes, I suppose: in vitro studies show that NaOCl is effective and unique for dissolving pulp tissues. I don't know the pertinent literature good enough, but I can quite well imagine that the root fillings show a better quality, less penetration of some dyes or whatever is used.

But clinically we have different criteria: healing (as determined by radiographic and clinical parameters) and survival. And these are the relevant criteria.

I have the suspicion that the effect of NaOCl is simply expected to occur also in a *clinical* situation - and that it is relevant. But has this been proven or sufficiently proven? Has this been proven for a *typical* clinical situation, that means for treatments in dental practices somewhere? We should bear in mind that most studies are reporting about the situation in some specialized centers where none of the dentists has to worry about decreased or lost profit in case of prolonged treatment time. It would be honest to at least give the time needed for treatment... and the costs the patient is charged.

Sure, we can complain about the low quality and insist that we should aim at an excellent treatment, however here is also a discussion how the costs for a dental treatment could be reduced....

And even in the specialized centers there seems to be no prove that NaOCl is of any advantage in apical healing or survival. That means a toxic material is recommended for routine use which has the status of a hypothesis. Nothing less, nothing more. What is wrong in such a case to ask the specialists for a prove?

Now, a comparative study has been published by the colleagues in Tibet. They have done what obviously all dentists in countries with advanced dentistry not even thought at. And, surprise, saline was as successful as NaOCl and caused just 1/5th of the complications. Immediately the question was asked if that study is reliable. Yes, ok, that is always a justified question. But it may only be asked as the first question if there are other studies of at least the same or - better - higher quality which show the opposite. But - are there *any*?

If not, if there is no prove of the opposite, just a theoretical assumption, then the first question should be: is our hypothesis wrong?

And indeed there are some open questions:

1. Is it necessary to remove all these tissues from the canal to obtain a better root canal filling than without removal? (And how to measure that?)

2. If yes - is this advantage of clinical relevance? (see below this list)

3. If yes - can it be achieved at all? (Intended overpress of NaOCl to dissolve tissues in the apical part of the canal?? Increased time for a better effect - 38 minutes? To be sure, the max would be better than this mean value! )

4. If yes - at which costs? (toxic damage, exploding costs?)

In Hülsmann/Schäfer "Probleme in der Endodontie" (Problems in Endodontics) you can read the sentence that - in order to get the tissues in the apex region dissolved - all studies had shown that the NaOCl must be overpressed. Which some sentences later is rated as inacceptable.

Thinking logical I must assume that - if all colleagues use the NaOCl in the recommended way - there remain lots of dead tissues in the apical ramifications, which have numerous openings into the PDL. Yes, the rest of the root canal is free of these tissues, and can be sealed(?) with an excellent(?) filling. But that is most probably irrelevant, since the body is not in contact with this part of the canal, it is in contact with the dead tissues at the apex, and the microorganisms residing here.

That means to me that by theory, supported by some studies, NaOCl is not useful at all if the criteria "apical healing" or "survival" are used.

That means if you would like to use and recommend NaOCl furtheron, you would need to do comparative clinical studies. Blinded, randomized, prospective.

And, I guess, you could get serious problems with your ethic committee.

Please, the use of a material throughout the whole dentistry is *not* a valuable prove in the sense of evidence based. There is the clear intention to also test established therapies, which are quite often established by means of tradition, or financial interest of some companies, or just a banal mistake in the process between planning a study and the print in a journal. Think at spinach: a simple mistyping of a decimal delimiter forced generations of children to a horrible meal. (Meanwhile I like spinach, but at those early times you could find it everywhere: in the face of my parents, on the floor and the walls around my seat, but never in my stomach.) It was the reason for a very successful comic, but it failed to be a better supply for iron..

So, without being *iron*ic (just a little), the technical approach is of course important. I remember a big congress in Germany long ago - I passed dozens of posters which all presented studies on the accuracy of endo files, fulfilling the ISO-criteria or not - important for the compatibility. But nobody could tell me if a deviation of a gradient angle of 0.5 degree was of any clinical relevance (provided the material is solely bought from the same company)... And now we have systems with a completely different geometry; at those times they would have been excluded from a presentation, I guess.

But in the end it is the clinical success which is decisive. And here I see massive deficiencies. Not only in endodontics, also in surgery. But of course much less. I guess the value of our surgical treatments should be rated by another speciality, not by the surgeons. This prevents too much bias and helps to take off the blinders.

Dear Yango,

Many thanks for your kind explanation. You are making it a wonderful discussion!.

- Regarding the study performed in Tibet. It looks very interesting. Can you please send us a copy so we can discuss it details.

- I totally agree with you that we should minimize the application of toxic materials due to the potential risks. but please let me ask you the question in the reverse way. "Why we should leave toxic necrotic tissues, exotoxins and endotoxins resulted from a huge number of microorganisms in the patient root canals for his life time?". This also is a potential risk and the difference between it and NaOCl, that NaOCl will only be applied for limited time and with cautious application, no harm would occur, but the microbial toxins is always in dynamic process with the immune response even if they are entrapped in dentinal tubules/small accessory canals, and this may have a clinical implication, especially in endo-perio lesions (Dongari and Lambrianidis 1988, Rotstein and Simon 2006, Ahmed 2012).

The ability of NaOCl to dissolve the remaining vital/necrotic tissues and its potent antimicrobial activity is beneficial to remove/minimize these irritants with potential risks, that are out of reach of root canal instruments. That's why RCT is a "chemo-mechanical procedure.", and that is the reason why in some cases the removal of the smear layer is indicated.

- Regarding the application of NaOCl and its extrusion into the periapical area, there are a number of delivery needles such as side vented needles and EndoVac that have proven to decrease the amount of extrusion. Indeed, they are more expensive, but I don't use them in every case.

- I believe that every step in RCT has a potential risk and hazard; we only try to find out the ttt option with the least harm to the patient. I believe that removal of remaining pulp tissues and microbial irritants via NaOCl worth its indication in RCT.

Dear Hany,

yes, I agree, I like this discussion also. I thank you for your comments and answers. Only that way we will be able to advance. I know that it is not easy discussing with me; especially if there is so little proven knowledge. In these scenarios it is easy to question everything - which is my part here - and difficult to defend established methods by arguing. And it s not a rare experience that the colleagues are enervated and therefore start to ignore the one who is disturbing the holy but unproven consensus. So again, thank you very much; I promise to keep critical, but (I hope) always fair.

And yes, you are right that we have to get rid of the infection and the infectious tissues. That has to be a primary goal. I rate it that important that in cases where pulp necrosis and consecutive infection are predictable but have not yet established (trauma cases! tooth avulsion, tooth intrusion, other severe dislocation injuries, transplantation of mature teeth, mainly primary canines) I'm fighting against the whole world of endodontology to establish (again) the prophylactic endo, best done extraorally from a retrograde direction with a special system. It is somehow ridiculous that I try to fulfil the basic demands of endodontology (complete control, better: prevention of infection) while the colleagues in these cases see no problem accepting an infection in the endodontium for 10 days (and for 3 weeks or longer in immature teeth while hoping for a revascularisation to occur) but are very directive if there might a single bacterium stumble into the already infected pulp chamber.... But that's a different topic which is discussed elsewhere (https://www.researchgate.net/post/Does_anyone_work_with_dental_replantation_after_avulsion). Here I cite it to demonstrate that I rate (pathogenic) microorganisms as not acceptable in our body. I consider them as enemy #1, and our defense system is programmed to destroy even (parts of) our body within shortest time, even really hard, mineralized tissues to expose the enemy to the defense system (dentine and cementum and bone: infection related resorptions) or to "isolate and exfoliate" the enemy (by destroying and demarking bone and other tissues).

And yes, I know the problem that it is not possible to completely clean the root canal by mechanical preparation alone (except in certain cases using the above mentioned system, but this is restricted to trauma cases and round to oval root diameters). It is the main reason that I don't recommend "conventional" extraoral root canal therapy.

I don't think that it is ok if we accept a toxic material just because there are other toxic materials around. And I think there is a qualitative difference: despite all success with prevention we will see enough teeth with pulp necrosis and infection of these tissues. When the patient comes in we have no influence on the situation, the bacteria are already there. But we have the choice concerning treatment, here: the choice of the irrigant.

Furthermore, it is still a theoretical discussion, dependent on a vast number of assumptions, hopes, estimations. "If it is done in a correct way...." is the sentence most often written here. But: how is the "correct way" defined? How do you know and how do you record that you did a good job? Or a bad one? Suffers the patient from some pain? What if there is an anesthsia? These are ex post criteria; are there any ex ante criteria for this correct usage? Is correct usage defined as "no extrusion"? Besides the verification problem: According to the studies cited by Hülsmann/Schäfer many remnants of pulp tissues and the bacteria are left in the apical ramifications if you don't extrude the NaOCl: should then the correct treatment try to remove this "permanent load of toxic products" at the cost of a "temporary toxic load" related to a planned extrusion of NaOCl? Nobody dared to demand that, but that would be the logical consequence...

And where we have concrete data, it is a bit disappointing: the expensive delivery needles help to "decrease the amount of extrusion". That is the expression an optimist would use. The pessimist would say: also with these needles the extrusion can't be avoided ....

At the moment I am somewhat disappointed. Not only by the fact that we can't do a perfect endo; I think that we can't expect that; the issue is much too complex, we simply have no chance. I'm much more embarrassed that nobody seems to be irritated by the fact that dentistry worldwide is using materials which obviously have never been proven in a comparative study. Despite these materials are used every day in millions of cases, and thus experience with the material is huge, there are enough patients in every age group, with or without some systemic illnesses; there could be excellent studies. Why is that so? Are the results so mean that nobody dares to present his data? Is even a one-year-study just too long that nobody wants to tie himself to that centre for such a long time, being aware that today you have to go abroad to be acknowledged as a "scientist" - but as a scientist of short-term studies? Or is it the first sign, a kind of a seismograph, which gives us the prove that we will soon no longer need an endo because we will then have teeth from the laboratory, which are either resistant to caries or are just changed every two years?

I was not aware of this. I thought the whole protocol would have been some hundred or thousand times been proven and tested and proven. At least here in Germany the colleagues doing endo have a very self-confident behaviour (at least since the main topic at the implantology congresses is periimplantitis), I thought this is based on tremendous knowledge of what they are doing. Now I learn dentistry is a science which is more or less like a swiss cheese - but nearly completely showing the holes, and only sparsely some cheese bridges.

I recently had made a similar observation: the endo treatment recommended in severe trauma cases, namely avulsion, has never been proven at all; it never had been tested completely in an animal model, not in a single instance, and if partly tested and compared to other strategies/methods in animals, and also if directly compared clinically or indirectly (data of different (non-comparative) case-series studies put together) it showed always meaner results. This contrasted quite a bit to the unshakable conviction of being right with the conventional endo, and accordingly the guidelines were written.

It is a funny thing with these scientists; the more I dive into science expecting facts and data as decisive factors I find emotional and political decisions. Seems that scientists are also humans ;-)

Have a nice day all you out there.

Yango

Dear Yango,

I also agree with you. Sharing opinions and different perspectives based on scientific evidence and clinical experience is of prime importance.

- I think we now have an agreement that the removal of remaining pulp tissues and microbial irritants is essential, and I guess now you may agree with me regarding the unsuitability of saline to be a primary root canal irrigant during the chemo-mechanical procedure.

- So now what are the other options instead of NaOCl to remove those irritants??. Indeed, many studies investigated the potential use of other irrigants such as CHX, hydrogen peroxide, MTAD, EDTA, etc; however, most, if not all, of studies showed that NaOCl fulfill most of the requirements, and other irrigants can only be used as an adjunct.

- OK the question now is, Is there a guarantee that all those toxins in lateral canals, apical ramifications will be removed by NaOCl?. The answer is NO. The only way that we judge our RCT is to extract the tooth and perform fixation/decalcification and staining to examine the presence/absence of remaining tissues and/or microorganisms. Even if, we are able to confirm this in one tooth, we can not guarantee success via the application of this ttt approach in other teeth due to the huge anatomical variations in the root canal among different ethnic groups superimposed by age changes.

That's why I believe it is very difficult, if not impossible, to prove the criteria you have mentioned such as whether in this case I have done some extrusion or not and whether the postoperative pain was caused by this extrusion or by other factors, whether I have removed the remaining pulp and microbial irritants or not, whether this extrusion has removed the tissues in apical ramifications or not etc.

- I believe that NaOCl is like any drug; Millions of people around the world take antibiotics with potential risks of diarrhea/vomiting/anorexia/etc, which is similar to many other drugs with reported side effects. Is this mean that we withdraw the drug?. The answer is NO, because it is used to treat a critical illness, and some side effects should be suspected. I believe that this the same regarding some postoperative pain following RCT performed by NaOCl (indeed, NaOCl accident is not a normal side effect).

- The selective toxicity of a given irrigant, (toxic to microorganisms and nontoxic to our living cells in the periapical area), while maintaining the tissue dissolving effect inside the canal, is like a dream of mine; however, I am not sure whether this dream can come true or not!!

- I believe Yango after all these research studies and clinical investigations, nothing is better than prevention, nothing is better than what God Has provided to us. Actually, I never consider bacteria (this marvelous creature) as an enemy. Never at all. I believe that our carelessness to preserve our teeth is the main reason of all these consequences, and for me if people will gonna take care of their teeth and my endodontic practice will be limited to fewer cases and some retreatments, I will be happy because the money spent for such materials, including research, will gonna be spent to other more critical medical branches such as chronic heart diseases, TB patients and others.

At the end of the story, as you said, despite the huge responsibility on scientists, they still are humans, and when we go deeper into knowledge, our limitations could be felt better!!

Ich wünsche Ihnen einen guten Tag!

Dear Hany,

#1 NaOCl vs. saline

yes, I agree that saline has not the property to dissolve dead (and fortunately) vital tissues, while NaOCl has. Sure, consensus.

"The removal of remaining pulp tissues and microbial irritants is essential". If that is meant as a goal: Yes, I agree. If that is meant as clinical experience, I say no: as you state lateron, this goal can't be reached: "we can not guarantee success via the application of this ttt approach"

And that is the point. It is not the question whether this or that solution can dissolve better some tissue remnants. It is not the question that a complete removal of these tissues is essential for the success.

It is the question whether this can be achieved in the *clinical* situation, regarding these anatomic variations, the problems of reaching the apical area, ...

Thus, if you can't use a solution in a way that it can evoke its undoubted properties, then this solution is useless for this purpose. Obviously, saline is also useless, because it has not this desired property at all. Thus, it is as ineffective as NaOCl.

If I have two irrigants, both ineffective, which one to chose? One is toxic, more expensive, has a bad smell, is disliked by patients, and most probably by dentists and assistants as well....

That means, you would need some very convincing *data* which undoubtedly show a clear advantage in the healing or the survival of the teeth treated with NaOCl compared to saline.

Unfortunately, in the actual study there was no difference in healing, but significantly more complications with NaOCl.... Well, this study seems to be all that we have. At least nobody was able to add any other...

however, the observation time is still low, the number of cases not bad, but not exceptional. Thus, there is still a chance for NaOCl, but in my opinion this study has to be done, verified or rejected by other groups, and best immediately...

What I could imagine: NaOCl is effective where it can long enough operate on the tissues: in the whole root canal without the apex region. I can imagine that it is of relevance to have these 95% cleaned to allow a better root canal filling which is longer withstanding a reinfection in case the coronal seal is lost.... But this is a pure assumption; maybe it is already proven experimentally. And even if yes, you would have to verify your experimental data by clinical studies.

What I really can't understand: why have comparative clinical studies not been done yet?

Do you reject the approach of evidence based for some reasons? In general, or in this specific question?

Dear Hani,

#2 bacteria

You seem to be fascinated by these bacteria... yes, but that's only mentally. I'm sure that your body would tell a very different story if bacteria would enter it...

And even, if you are right that we are responsible for our teeth - if bacteria manage to get into our body (and there are many other ways besides rotten teeth) our body reacts immediately by firing with full power what is available as ammunition onto these visitors. You only do that with enemies, but never with friends.

Just think about how many of your "non-enemies" live within our body. And live there undisturbed? I mean, not behind a defense line built up by some very potent cells and other defense compartments? Even the bacteria which are really good for us, helping to digest, for example, are located outside of our body, on the other side of the borderline which is defined by epithelium.....

And, btw, you also have the meaning that it is essential to not only remove "remaining pulp tissues" from the root canal, but also "microbial irritants". For what reason if they are not the enemy of our body?

I prefer a more practical approach: I observe that our body is prepared to destroy itself in case of an infection if the enemy can't be reached in time in another way by our defense.

Yes, it is a very basic level which I use for rating bacteria. Of course you may like them mentally, admire them for being the form of life which obviously is very successful, and very old. But that is a different level, our body, also yours, obviously can't afford any generousity or admiration, and I guess, he knows better what to do. And he knows very well that our brain is not reliable in these questions - thus it is simply excluded from any influence on the basic systems responsible for running our body....;-)

Hi Yango,

I missed your interesting discussions for a while, and I am sorry for that. I was having an IADR conference and a couple things to do and write. But anyway, I am back!.

- Your question why there is no clinical comparative studies to provide an evidence is very logic.

I believe that this issue is restricted on the difficulty to have an ethical approval to formulate such a clinical study. For instance, we need to have an evidence that the application of rubber dam increases the rate of clinical success. How can you formulate this study on human?. How can we get an ethical approval to treat a group of patient without rubber dam?. I think this is very difficult, if not impossible. This is quite similar to NaOCl which we know and agree (and we have in vitro experimental evidence) that it has tissue dissolving effect and potent antimicrobial activity more than saline. So why you need to prove this in human, and probably subject a group of patients to a treatment procedure that you already have a proof that it is less effective in vitro.

Okay. So now we only have the animal models to provide such evidence, and this would cost some money and would require long term follow up. In my own opinion, if I have the animals and money, I will gonna use them for another experiment!!.

- Regarding the bacteria, actually I respect the interactive biological mechanisms of this microorganism to survive, even under harsh enviromental conditions. Sometimes, I believe we should learn from this creature how to face hard times and how to co-aggregate and interact together to face big problems!!.

Indeed, I agree with you that we should face any infection, but probably I also respect this microorganism because my father is a professor of microbiology!. By the way, he took his PhD in Goettingen more than 30 years ago, and I was born there!!

May I quote Socrates "I know that I know nothing"? We all have knowledge and experience of the dramatic decrease of bad prognosis resulting of good application of asepsis since the beginning of the last century when performing surgical intervention (root canal treatment is a surgical intervention). Nowadays, the concept of ecosystem provides different approach of how research should be guided and how the 21st practitioner should develop his own critical thinking as a doctor rather than a technician or simple expert.

This intense discussion dealt with issues largely developed these decades and provided in these books.

Textbook of Endodontology By Gunnar Bergenholtz, Preben Hørsted-Bindslev, Claes Reit 2010

Seltzer and Bender's Dental Pulp By Kenneth M. Hargreaves, Ph.D., Harold E. Goodis, Franklin R. Tay,

2012

Pathways of the Pulp 10th edition By Kenneth M. Hargreaves, and Stephen Cohen, 2011

Endodontics: Principles and Practice, 4e By Mahmoud Torabinejad and Richard E. Walton DMD M 2009.

May I recommend reading these article still valuable so far? I try to upload these documents appended on my answer.

Sjögren U, Hägglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. Journal of Endodontics. oct 1990;16(10):498‑504.

The oral ecosystem: implications for education. H. M. Eriksen, V. Dimitrov, M. Rohlin, K. Petersson and G. Svensäter; Eur J Dent Educ 2006; 10: 192–196

With best regards

The second article

Many thanks Gerard for your kind opinion and attachments. Indeed, I agree with you that our knowledge, despite the current advances, is still limited.

I always try to address these issues (bacterial ecosystem/biofilms/etc) in my publications whenever I have the chance.

- I also recommend reading a very nice book (not dental) written by Majno and Joris entitiled "Cells, tissues and disease". This book has many useful information.

Best regards.

Dear Hany, dear Gérard,

thanks a lot for the ongoing discussion.

I look forwrd to your studies, Hany. Irrespective of the results: you will get a well known man in endodontology...

Yes, you are right that you claim kethical reasons. But you can just change your point of view:

We had a patient who got a injection meant as an anesthesia in the upper jaw. Unfortunately the dentist took a syringe with NaOCl. This meant a horrible way for this patient with months of pain, loss of a good portion of the palatal tissues.

You may argue that this would not happen if everyone would have acted in a correct way, but we all are humans, and we make mistakes, and taking the wrong syringe is *not* an unusal action. There are other examples published (already cited book "Problems in Endodontology") and some more, NaOCl spattered into eyes, and some more. This is an inherent problem of applying this toxic irrigation.

Furthermore, I attach a picture of a 40-y-old lady, which I just had as a patient. An exeptionally good looking lady, btw - after 3 months of cortocoid therapy (initially 60mg/d!), lying in a hospital for a month. She has lost her work meanwhile. And since she has finished with the corticoids she has the feeling as if there would be a recurrence soon...

This is the situation after repeated endodontic treatments in an upper molar. I had a long discussoin with her, for more than an hour, to find out what has happened. She told me that every time after these endo sessions she got some efflorescences intraorally which she rated as a kind of virus infection (she said "Herpes"), but never showed it to the doctors, or mentioned that. But it got worse with time, and ended with that emergency hospitalisation. And there was no such experiences before the rct started.

I will get some more information tomorrow (blood counts) and then will have some telephone calls with the dermatologists (who had no explanation for her situation) and a toxicologist and her home doctor. So far I have the information that CRP is minimal (within normal range), while LDH and leucocytes are increased. Anyone with some knowledge in that field?

Thus, we don't know yet what the reason was for this heavy reaction. But there is a close timely coincidence between the endo and the reactions. There are no explanations from the dermatologists. I have the suspicion that the endo treatment (finally unsucessful, tooth is extracted meanwhile; the treatments in question were irrigation of the root canals plus instillation of ca-hydroxide due to persistent pain) is the source for the reaction. And some examples in the book "Problems in Endodotics" seem to be quite similar....

And now there is a study which shows that NaOCl is of no advantage compared to saline....

To Gérard:

Could you please give the pages which you consider important in these books for this discussion? Best would be if you could copy the parapgraphs. I don't have access to all the most recent editions, and if I had, it would still be the big question whether I could find out what you meant....

Furthermore, I don't like books as sources for a scientific discussion: even if done with the best intention, they provide us with the personal opinion of the author, which has not undergone any review process.

The articles don't provide any information on the issue in question, they did not compare naocl to other irrigants. Nevertheless, they are quite interesting (and I cite the Sjögren article in my lectures).

I will update the information on the lady as soon as I have it.

I think, I will open an own question for that. Maybe we get some valuable information from other specialities....

Kind regards

Yango

Dear dr pohl

in 30 years of practice one will come in contact with different diseases, patient conditions, treatment side effects, etc. Yes, i agree with you that i would prefere to see naocl replced today and not wait for tomorrow.

We have looked into many different technologies and materials. Guess we are close before introducing the next generation butbthe question stays:

how easy will it be to replce a classic golden standard?

Will the world of science support the shift of paradigm?

Will the general dental practioner easily accept the shift?

Will it be easy to introduce a new remunaration?

We should look in the past.....how difficult was it, is it to replace amalgam, etc.?

Dear Dr Steier,

yes, you are right with your questions, however, it is sad that these questions are that important...

The look into the past should alert us, should force us to reconsider what we are doing, it should not be an excuse for doing nothing, for just accepting what our ancestors developed or used. Maybe they were right, but maybe they were wrong. Thus, as scientists, it is our duty to re-evaluate, to check, to compare also well established treatments. We never should be contented, but also not disappointed.