Hi. My name is Dr. Scott Resnick.
I'm a practicing endodontist in Manhattan, New York.
Today we are going to describe the various steps of endodontics
from start to finish.
Endodontics is an intricate procedure, for sure,
but can be very rewarding for both clinicians
as well as, of course, our patients.
Let's take a minute to state the main goal of endodontics.
It is the prevention and/or elimination of bacterial infection
and inflammation associated with the canal system.
From the beginning of modern endodontics,
we have relied on the radiograph as a critical part of our diagnosis,
prognosis, and, of course, treatment.
Today we have an additional tool that has quickly become
the standard and that is cone beam computed tomography or CB/CT.
Regarding the importance of this technology,
the American Association of Endodontics and
the American Academy of Oral and Maxillofacial Radiology issued a joint
position statement on when CB/CT should be employed.
This paper starts out by telling us when CB/CT should not be used.
It said CB/CT should only be used if the
patient's history and clinical examination demonstrate that the benefit
to the patient outweighs the potential risks.
CB/CT should not be used for endodontic diagnosis
or for screening purposes in the absence of clinical signs and symptoms.
The clinician should only use CB/CT when the need for imaging
cannot be met by lower dose two-dimensional radiography.
Low, Dula, and Burgin, et al, compared periapical radiography
and limited cone beam computed tomography in posterior maxillary teeth referred for apical surgery.
They found that 34% of the lesions were missed by periapical radiography
and virtually no lesions were missed with cone beam computed tomography.
So how does this bear out in the real world?
Well, this patient presented shortly after traumatic injury to the maxillary anterior teeth.
You can clearly see a slightly widened PDL on tooth number eight
and radiolucent lines indicating possible fracture.
It does not tell us the extent of the likely fracture
and does not tell us if it's buccal or lingual.
It does not tell us a lot of things because it is a two-dimensional picture of a three-dimensional object.
But when we take a cone beam, we can clearly see the extent of the fracture line.
We see how far below the crest of the bone it extends
and whether or not to even attempt treatment,
saving the patient time, pain, and of course money.
Today's patients have higher expectations and are more knowledgeable.
And as clinicians, the more we know, the more responsibility
we have to give them the treatments they deserve.
This is another case that illustrates the efficacy of cone beam when dealing with complicated situations.
What we have here is an endodontic failure
and it looks like a pretty straightforward failure.
Perhaps even one that I would make a small access through the existing crown
and then place a post or replace the crown.
It looks like there is a diffuse radiolucency at the apex, a slightly widened PDL,
and a tooth that perhaps we should consider for retreatment.
And if not retreatment, then possibly an apicoectomy.
That is, of course, until we took a cone beam and saw this fracture line in the tooth.
There is no way you could have ever predicted a fracture like this using conventional radiography.
Another really great example of the importance of cone beam
is in the diagnosis and treatment of resorption cases.
This is the resorption guide from Geoffrey Heithersay
and it shows the three classes of ECIR, or Extra Canal Invasive Resorption.
Class one is treatable.
Class two may be treatable.
Class three is probably not treatable,
and class four is clearly not treatable.
A two-dimensional picture of a three-dimensional object does not really show us much.
And the previous dentist reflected the tissue, made a small access prep,
filled it with amalgam, and then put the tissue back in place.
One year later the general dentist took this radiograph
showing evidence that the lesion had grown.
He then referred the patient to us and we, of course, immediately took a cone beam,
which not only showed the extent of the lesion but that it had spread to the lingual aspect of the tooth.
This helped us illustrate to the dentist and to the patient,
who was adamant about trying to save the tooth,
why this lesion was much too extensive to consider treating.
This is a patient who presented to us after access was made by a general dentist.
The general dentist at this point felt uncomfortable about finding all the anatomy
and wanted to stop before there was a perforation.
He knew they were close and so he sent the patient to our office.
We, of course, took this radiograph and were a bit alarmed
by how deep the access was relative to the furcation,
so we took a cone beam.
On the cone beam, we can see the extent of the access.
We can see actually how close it comes at its deepest point to the furcation.
in all dimensions.
We were able to determine that although the access looks pretty deep,
we are still in intact tooth and in fact it's a tooth we should be able to save.
We can look at this in increments, working our way up the canal
to see exactly how patent the canals are, where they are,
how much further we have to drill to get to them,
and all of this will greatly enhance our ability to get the result we want.
This case illustrates the importance of cone beam in endodontics
as much as any other case we could show you.
This is a root canal done by a general dentist
who subsequently placed a post and a long span bridge.
Six months later there is now radiographic evidence of pathology,
the patient is uncomfortable and the dentist sent him to our associate,
Dr. Courtney Linenberg, for an apicoectomy.
As part of her exam, she took a cone beam.
What she found was that there was actually a second root
that had never been treated and you can see it here.
You can also see the radiolucency at the apex.
So rather than remove this tooth or perform an apicoectomy,
she elected to make a small access through the porcelain bridge
and treat just the missed canal.
Her patient saw immediate results and as this six-month radiograph shows,
there is evidence that the lesion is shrinking.
This is an article by Sergio Kuttler
where he took 12 random extracted mandibular molars,
cut off the distal root, and then randomly selected two of the 12,
took radiographs and from the radiographs you can see they look pretty similar.
He then did a micro CT scan of each.
Look how dramatically different the anatomy is.
You could never tell that from the radiograph, but that is what we are facing so often.
We cannot possibly know from our instrumentation exactly what we are dealing with.
Micro CT scans are dramatic in that they show us all of the additional portals of exit
and how complicated the anatomy is.
This gives us a better understanding of why it is so important that we not only
instrument teeth well but irrigate well and use proper irrigants
that will remove the tissue and the biofilm from the canal walls.
Now not everyone is going to go out and buy one of these machines,
but it is likely that your local endodontists either has one or knows where to send their patients.
In our time it is hard to fathom a discussion on endodontics without
magnification on the order of a microscope.
No study Illustrated this more to me than the Buhrley/Barrows study of 2002.
It showed how difficult it was to find the mesial-buccal number two canal
of the maxillary first or second molar without magnification.
The canal which we all know is found somewhere around,
let's say 85% of the time, depending on the literature.
Well, without magnification they found it 17.2% of the time.
If you added magnification you were up at 62.5% of the time, an incredible jump.
If you then look at how often you would find that fourth canal
if you were using a microscope, you would be around 71% of the time.
One more illustration. This is the back of a $5 bill showing the Lincoln Memorial
and that is at 2.5 times magnification, which is pretty typical for loupes.
This is at approximately 15 times magnification using my microscope.
I would say that this is a pretty significant difference in magnification
and something we should all consider when delving into endodontics.
To illustrate even further the importance of technology,
I would like to show you a few research papers that really bring home
the extent of what we are dealing with
and why it is so important to embrace new technologies.
In a research paper by Karapinar and associates,
they found a mid-mesial canal in the mandibular first and second molar
18 to 22% of the time.
And Fan in his 3D modeling article,
found that 85% of mandibular first and second molars have an isthmus
in the apical five millimeters.
Clearly there is a potential for a large percent of endodontic procedures to fail
due to complicated anatomy present most of the time.
I mentioned Fan's article on the complex apical anatomy in the mesial root
of mandibular first and second molars.
This is an illustration from that article showing how complex the anatomy is.
In conclusion, we certainly can recognize the complexities that root canal treatment has to offer.
However, with the advancements in today's technology,
we can appreciate our newfound ability to treat such complex situations
with greater ease and confidence.
As I mentioned earlier, it is my belief that there are certain steps
in a root canal procedure that are absolutes.
I want to thank all of you for spending your time with me today
and I wish you and your patients all the best.