RCTed teeth = brittle??

[june_sp]

I've heard dentists say numerous times that root canal-treated teeth are brittle and that is the reason why the teeth need crowns.

But in my endo class, I swear I was taught that root canal-treated teeth do NOT become brittle, and the main reason for coronal restoration after RCT is to provide coronal seal to prevent bacteral re-entry. Even in my endo textbook, it says that it's only a "perception" that root canal-treated teeth become brittle. RCTed teeth are weak not because of their loss of moisture content but because of the loss of structural support due to access cavity and/or caries.

so which is right?
is it wrong to say that teeth become brittle after RCT?

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[tinman831]

I believe you are correct.

I've heard dentists say numerous times that root canal-treated teeth are brittle and that is the reason why the teeth need crowns.

But in my endo class, I swear I was taught that root canal-treated teeth do NOT become brittle, and the main reason for coronal restoration after RCT is to provide coronal seal to prevent bacteral re-entry. Even in my endo textbook, it says that it's only a "perception" that root canal-treated teeth become brittle. RCTed teeth are weak not because of their loss of moisture content but because of the loss of structural support due to access cavity and/or caries.

so which is right?
is it wrong to say that teeth become brittle after RCT?

 

[aphistis]

I've heard dentists say numerous times that root canal-treated teeth are brittle and that is the reason why the teeth need crowns.

But in my endo class, I swear I was taught that root canal-treated teeth do NOT become brittle, and the main reason for coronal restoration after RCT is to provide coronal seal to prevent bacteral re-entry. Even in my endo textbook, it says that it's only a "perception" that root canal-treated teeth become brittle. RCTed teeth are weak not because of their loss of moisture content but because of the loss of structural support due to access cavity and/or caries.

so which is right?
is it wrong to say that teeth become brittle after RCT?

I know what the textbooks say, but after extracting a few molars after failed endodontic treatment, you might find yourself questioning that statement too. 😉

 

[june_sp]

I know what the textbooks say, but after extracting a few molars after failed endodontic treatment, you might find yourself questioning that statement too. 😉

would you please elaborate on your comment? so you find that teeth DO get brittle after a RCT despite what the textbook says? i'd love to hear about your real life experience...after all i'm only a student..

 

[mike3kgt]

I have seen 40 year old MODBL amalgams with a sliver of buccal cusp left to "retain" the amalgam and their complete centric contact on the sliver of buccal cusp have to replaced because there are some recurrent caries.

I have also seen 4 month old RCT teeth with MOD amalgams with the tooth's lingual cusp sheared off without any serious occlusal prematurity.

While research may indicate statistical significant same "brittleness" pre vs. post RCT treatment, I can say definitively that after working these teeth for some time that they feel far more "brittle".

 

[Saddleshoes]

I've heard dentists say numerous times that root canal-treated teeth are brittle and that is the reason why the teeth need crowns.

But in my endo class, I swear I was taught that root canal-treated teeth do NOT become brittle, and the main reason for coronal restoration after RCT is to provide coronal seal to prevent bacteral re-entry. Even in my endo textbook, it says that it's only a "perception" that root canal-treated teeth become brittle. RCTed teeth are weak not because of their loss of moisture content but because of the loss of structural support due to access cavity and/or caries.

so which is right?
is it wrong to say that teeth become brittle after RCT?

I know what the "ivory tower world" of books say about the subject and I know what my years of experience doing "meatball dentistry" says about the subject at hand. Take it from someone in the real world...
It is true endo. treated teeth are more brittle!

 

[Lily143]

After having to extract RCT teeth due to vertical root fracture from the patient never coming back to get the crown done, I would have to disagree with what the textbooks say. Those dang RCT root tips have a tendency to break during extraction as well. They can be a nightmare.

 

[AirborneDentist]

I read your post to mean you were looking for the cause of the brittleness and not whether or not they are. They do become brittle due to loss of structure, but not due to lack of moisture

 

[omaralt]

I know what the textbooks say, but after extracting a few molars after failed endodontic treatment, you might find yourself questioning that statement too. 😉

100% agree. i was also taught that it's a myth, however extracting RCT treated teeth is a nightmare. they definitely seem more brittle and definitely break a lot more than normal teeth.

 

[armorshell]

The myth is that endo treated teeth become brittle dueto a lack of moisture because they are no longer perfused. This is wrong. What isn't wrong is that endo treated teeth are weakened by the access, radicular prep and post space, and are already compromised to begin with.

 

[DrJeff]

I know what the textbooks say, but after extracting a few molars after failed endodontic treatment, you might find yourself questioning that statement too. 😉

100% agree. i was also taught that it's a myth, however extracting RCT treated teeth is a nightmare. they definitely seem more brittle and definitely break a lot more than normal teeth.

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What they said.

Myth???? reality?????? I'm not sure. Anecdotally all I know is that an endo tooth in need of extraction vs. a non endo tooth (missing similar amounts of natural tooth structure due to caries/fracture) seems to fracture when I'm putting a forcep to it (especially in the apical 1/2-1/3rd of the root 😱 )

 

[june_sp]

The myth is that endo treated teeth become brittle dueto a lack of moisture because they are no longer perfused. This is wrong. What isn't wrong is that endo treated teeth are weakened by the access, radicular prep and post space, and are already compromised to begin with.

You've answered my question precisely. This is where i'm confused. As earlier commentors have mentioned, breakage of endodontically treated teeth are very common - this fact is not what i'm arguing against. However, the reason for this breakage is not because of the lack of moisture but due to compromised structural support - i.e. loss of marginal ridges, access hole and/or caries.

Thus, it IS wrong to say RCTed teeth get more brittle because the source of water and nutrient is cut?? I just don't want to be telling my patients the wrong thing when i begin practicing...

 

[june_sp]

^^^^^^^^^^^
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What they said.

Myth???? reality?????? I'm not sure. Anecdotally all I know is that an endo tooth in need of extraction vs. a non endo tooth (missing similar amounts of natural tooth structure due to caries/fracture) seems to fracture when I'm putting a forcep to it (especially in the apical 1/2-1/3rd of the root 😱 )

hmm...so i guess teeth DO get more brittle after RCT, but we are not sure exactly why?

 

[tinman831]

http://www.ncbi.nlm.nih.gov/pubmed/1402595

This study compared biomechanical properties (punch shear strength, toughness, hardness, and load to fracture) of 23 endodontically treated teeth (mean time since endodontic treatment: 10.1 yr) and their contralateral vital pairs. Analyses using paired t tests revealed no significant differences in punch shear strength, toughness, and load to fracture between the two groups. Vital dentin was 3.5% harder than dentin from contralateral endodontically treated teeth (p = 0.002). The similarity between the biomechanical properties of endodontically treated teeth and their contralateral vital pairs indicates that teeth do not become more brittle following endodontic treatment. Other factors may be more critical to failure of endodontically treated teeth.

http://www3.interscience.wiley.com/journal/119286566/abstract?CRETRY=1&SRETRY=0

Abstract – The moisture content of vital and endodontically treated teeth was compared in matched pairs of contralateral human teeth extracted for prosthodontic reasons. Samples from each tooth were weighed then placed in an oven to remove the unbound water from the dentin. Weighing was carried out daily until a constant weight was achieved for three days. The moisture content was then calculated and expressed as a percentage of the initial sample weight. It was found that vital dentin had a moisture content of 12.35% whilst dentin from endodontically treated teeth had a moisture content of 12.10%. These results indicated that there was no significant difference in the moisture content between endodontically treated teeth and vital teeth.

http://books.google.com/books?id=vO...ntically treated teeth become brittle&f=false

 

[DrJeff]

http://www.ncbi.nlm.nih.gov/pubmed/1402595
http://www3.interscience.wiley.com/journal/119286566/abstract?CRETRY=1&SRETRY=0



http://books.google.com/books?id=vO...ntically treated teeth become brittle&f=false

Like I said, I know it's anecdotal, but this is one of those times when I feel that what an in vitro test shows vs. what the real life, in vivo situation is are different (atleast from what I see happening in my chairs in my office)

 

[armorshell]

Like I said, I know it's anecdotal, but this is one of those times when I feel that what an in vitro test shows vs. what the real life, in vivo situation is are different (atleast from what I see happening in my chairs in my office)

True, but you can't argue with the science being presented. This is more or less inarguable evidence that endo treated teeth are not more brittle than vital teeth. But brittle has a very specific meaning and in the context of these studies, does not mean "breaks easier during extractions."

There's no contradiction in saying endo treated teeth are not brittle AND fall apart during extractions.

 

[sokrman14]

The myth is that endo treated teeth become brittle dueto a lack of moisture because they are no longer perfused. This is wrong. What isn't wrong is that endo treated teeth are weakened by the access, radicular prep and post space, and are already compromised to begin with.

That is what I have been taught as well. "Dehydration" of the tooth is merely a secondary cause of brittleness that is not supposed to be much of a factor. They merely become weaker because of a loss of internal tooth structure. A restoration with cuspal coverage is highly recommended to prevent the fracture of an endodontically treated tooth because of the weaker structure.

 

[june_sp]

True, but you can't argue with the science being presented. This is more or less inaguable evidence that endo treated teeth are not more brittle than vital teeth. But brittle has a very specific meaning and in the context of these studies, does not mean "breaks easier during extractions."

There's no contradiction in saying endo treated teeth are not brittle AND fall apart during extractions.

thanks for being so clear! 🙂 👍

and thanks everyone for all the replies!!

 

[DrJeff]

True, but you can't argue with the science being presented. This is more or less inaguable evidence that endo treated teeth are not more brittle than vital teeth. But brittle has a very specific meaning and in the context of these studies, does not mean "breaks easier during extractions."

There's no contradiction in saying endo treated teeth are not brittle AND fall apart during extractions.

Not arguing with the science at all. Just saying that sometimes the results that can be obtained in a controlled in vitro situation might be different than what a clinician finds in an in vivo situation where it's often tougher to control the variables. It's the same thing with reported bonding agent strenghts. What does say 45 mPa of in the lab, bench top bond strength mean to a clincian as he/she is trying to use it on a fidgety 9 year old who just broke his/her front tooth, with a small mouth and a high salivary flow???

 

[mike3kgt]

Not arguing with the science at all. Just saying that sometimes the results that can be obtained in a controlled in vitro situation might be different than what a clinician finds in an in vivo situation where it's often tougher to control the variables. It's the same thing with reported bonding agent strenghts. What does say 45 mPa of in the lab, bench top bond strength mean to a clincian as he/she is trying to use it on a fidgety 9 year old who just broke his/her front tooth, with a small mouth and a high salivary flow???

Agree 100%. Let's hear from more dentists (other than endodontists, dental students, and especially endo residents) about experiences with endo treated vs. non-endo treated.

There are quite a few things in dentistry where people believe ancedotal things or empirical evidence just based upon dogmas or dogmatic teaching styles. Very many examples in removable literature.

I know from my own personal experience that endo treated teeth are much much more prone to breaking while extracting, in function (without coverage) and feel more brittle. Whether your definition of "brittle" may not be scientifically accurate in regards to endo treated teeth, I can say defintively that after thousands and thousands of extractions, when looking at two identical molars with same clinical presentations except that one has endo and had it performed 30 years ago... I'd be much more excited to take out the non-RCT tooth anyday.

P.S. I love scientific data to understand dentistry more (look at my previous posts) but I think this is a great example of when, sometimes, you need to trust your experience more.