Allan Deutsch
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have found that in the last five to seven years we are doing fewer and
fewer endodontic-type surgeries, that is fewer apicoectomies. The
endodontics is becoming more and more predictable, and with the advent
of better technology conservative endodontic retreatment has become the
procedure of choice.
However, in many instances before we can redo the
endo we must first disassemble the restoration. This disassembly
procedure can oftentimes be tougher than redoing the root canal.
We have found out that clinicians across the country are charging a separate
fee for disassembly.
Removing a post in order to gain access to the root canal system
and still leaving a restorable tooth is no easy task. We used to
just drill the posts out. However, the bur would often slip off the metal
post and gouge out the post hole, sometimes dangerously thinning out the
root to the point where it was not restorable. Now we have the microscope,
and we are able to use a 1/2 or 1 round bur and see where to place it on
the post. This has made drilling out the posts much easier.
However it is still no picnic.
Initial Steps
Before we begin removal, we must consider several factors in order
to obtain a successful result. First, what type of post is it?
Is it passive or active. Passive posts are held in with cement.
Two typical passive post types are cast posts and paraposts. Active
posts are typically threaded posts, like Dentatus, Vlock and Flexi-post.
With both types of systems (active and passive), the first step
is to expose the cement. Carefully remove all the core material around
the post and expose as much of the post as possible right down to the coronal
dentin of the post hole.
Next, break the cement seal if possible or at least
disturb it. It is at this stage that some new technology comes in
handy. I just came back from Dr. Cliff Ruddles Endodontic retreatment
course in Santa Barbara. He advocates, and we here on 57th street
use, the “Spartan Ultrasonic” unit. Dr. Ruddle has designed a series
of very thin and long Ultrasonic tips to be used in removing posts as well
as separated endodontic instruments (see Figure 1).
The Spartan ultrasonic is used dry at the lowest power setting.
It cuts the dentin like the thinnest bur you can imagine. We now
trough around the post and break up the cement. As you use this instrument,
your assistant should be blowing air on the field to maintain your visibility.
Naturally, since everything is so small you must use either some type of
magnifying glasses or a microscope. In many instances, once the cement
seal is broken the post will begin to vibrate and soon come out, if it
is a passive post.
Removing Threaded Posts
If it is a threaded post , you can now place either the wrench or a
hemostat on the post and thread it out of the root. If the post is
not moving, you can apply a thicker ultrasonic tip directly to the post
and let it vibrate the post for several minutes. You can even hold
the post with a forceps and touch the ultrasonic tip to the forceps and
hence the post.
If the post still won’t budge, you can use the Ruddle post removal
system made by Analytic Technology. Here a trephine is drilled over
the post to standardize the post’s diameter. Next, a tap is threaded
onto the post. Finally, the extraction plier is placed onto the tap.
At this point, an ultrasonic tip can be placed onto the tap and again loosen
or disturb the cement seal. Now the extraction plier is activated
and the post is removed. Yes, this really does work!
The beauty of all these procedures is that the post is removed
without “bombing out” the inside of the root. Because if you can’t
restore it, what good are you really doing for the patient?
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