From: Marga Ree
To: ROOTS
Sent: Friday, August 05, 2005 5:24 PM
Subject: [roots] Canal projectors a la John Munce

This patient came in with an acute apical periodontitis of tooth # 37. She was on vacation in Italy when she got a flare-up.
She consulted a dentist, but he told her that he could only extract the tooth. "An endo was not possible, because of the presence
of the posts and bridge"

She refused to have the tooth extracted and requested the dentist to prescribe her an antibiotic and a pain killer, which he did.
She decided to go home the same day, and to seek treatment in her home town in the Netherlands. After a terrible 12 hour drive,
she called our office, because we did a rct on her daughter some years ago.

Treatment: removal of the bridge with a crown and bridge remover, removal of the cast build-up and posts with US tips, C&S,
application of Ca(OH)2 and reschedule her for a next visit. There was not enough tooth structure to recement the bridge without
running the risk that it would come loose, so I did the canal projector technique of John Munce, which works great in these situations.
Because I had not the original kit, I used the purple capillary tips of Ultradent.

In summary: Fit the capillary tips in the canals and adjust the length by clipping them to the right size. After insertion of the
canal projectors, acid etch, apply primer and bonding. Prepare the inner side of the restoration by applying a separation medium like
vaseline, and make an adhesive build-up of a self cured composite with the bridge serving as a mold. Apply composite with a needle tube
in the tooth and in the crown, put the bridge back in place, check the occlusion, and after setting of the composite you will be able
to take it apart from the abutment tooth.

Removal of the cap tips is very easy by screwing in a hedstrom file. I prefer to connect the preserved canals (see pic) and leave an outer
wall of composite in place. Apply Ca(OH)2,  cover the orifices and pulp chamber with cavit, and recement the bridge with a temporary cement.

From the day of the first treatment, the complaints sudsided. I finished treatment in the second session. Fiber post in distal canal and a
composite build-up. Although the margins of the bridge are not 100% perfect, the fit is acceptable, and there was no decay underneath it.
We decided to recement it and monitor for healing. Which is taking place, see 6 months follow-up rad. - Marga


Very nice. Do they call an amalgam stuffed into the top of the canals a post in Italy? ;-)- Alan Cady

Marga, excellent as usual. It is always a pleasure to look at your cases. That's why you are called the "Endofee" - Jörg

Great case!  Great tip!  Great presentation!   APPLAUSE! One tip that I have found uselful is to paint a *very*  thin layer of
Fit-Checker on  the inside of the crown before using it to build up the 'retrograde' core.   This acts a  pseudo die spacer. - Ken Lipworth

Awesome. Do you AE & bond with a dam in place, or do you isolate with cotton rolls while you place the composite and then quickly
insert the bridge? DougR

Thanks Doug,Yes I always AE & prime and bond with the dam in place. Then it depends:
If the clamp and the rubber dam don't interfere with the insertion of the bridge then I insert the bridge under rubber dam and as
soon as it is seated, I quickly remove the dam and let the patient close to check the occlusion. I prefer this situation, and
if possible I take care of this from the start of the treatment when I place the rubber dam, e.g. by making a slit dam which I cover
during treatment with a light cured secondary isolation material like opal dam.

If the rubber dam does interfere, I AE & prime and bond with the dam in place and cover the preparation with a first layer of composite.
Then I isolate with cotton rolls and if necessary, I put a heamostatic retraction cord in the sulcus. If necessary, I AE & prime and bond
again, and apply the second layer of composite in the prepared tooth and in the bridge and insert it.

After the setting of the composite, I remove the bridge, and remove the surplus of composite from the interdental space and below the
outline. Then I clean the bridge with alcohol and a sandblaster, and recement it either with a temporary or definitive cement. - Marga
 Hi Marga, I've heard of the canal projectors, but it's the first time I see them in action. Thanks. - Hani

Marga, a simply fantastic case.  I have wondered about how to do the Mounce projectors and this is wondeful.  Did  you have to cut down the
purple tips constantly to make sure that the bridge fit on it again when you did the buildups .Wonderful treatment, great photos,
educational, and awesome healing. CLAP CLAP CLAP - Thank you very much for the fine presentation - Glenn


Hi Glenn, You are always so enthousiastic in your comments and remarks, thanks a lot for your nice feed back!
About the length of the tips, I just estimate this by cutting them at a  certain length, and then try to insert the bridge,
which I preferably do under rubber dam, see my answer to DougR. After I made sure that the bridge fits properly on them,
I apply the self  cure composite in the tooth and in the bridge, like I explained to DougR. - Marga

A truly remarkable effort Marga! You are certainly a master clinician with amazing skills (and a 'saviour' of many teeth
which others would have definitely condemned to extraction). The technique you have described (as with many of your other posts)
is fascinating and innovative. Some quick questions about this case: What (realistic) prognosis did you offer the patient?
Are you not concerned about the minimal available natural ferrule? Will the resin bond have a 'reasonable' long-term survival;
Will it undergo rapid hydrolysis, &/or simply break down soon due to bond/core flexural fatigue as a consequence of the
demanding occlusal stresses in this region? Why did the case really fail in the first place? I feel occlusal forces and the
lack of 'satisfactory' ferrule may have being contributory factors towards failure. Lastly, are you not concerned about possible
vertical root fracture of the distal root (due to presence of a post associated with a very minimal ferrule)? - Peter

Peter, Thanks for your compliments, which I appreciate very much.

About your questions:
Are you not concerned about the minimal available natural ferrule? Will the resin bond have a 'reasonable' long-term survival;
Will it undergo rapid hydrolysis, &/or simply break down soon due to bond/core flexural fatigue as a consequence of the demanding
occlusal stresses in this region?
Yes, there is a minimal ferrule. That is one of the reasons that I decided to re-use the current bridge and monitor this case.
If tooth # 37 will fail, then there is always the option of placing 2 implants. And yes, I know that theoretically the chance exists
that the bond will fail due to flexural fatigue. But...., I have made a lot of these adhesive composite build-ups,
for more than 15 years, and to be honest, I don't see them failing frequently, on the contrary, they function without any problems
in the vast majority of cases.
But I realize that this is a very unscientific statement.......
:-))  I do know that the fabrication of a neat composite filling or build-up is very technique sensitive, so very dependent on the
operator who is executing the treatment. A poorly performed amalgam build-up can still be an adequate restoration, but a poorly
performed composite will never become a success.
Why did the case really fail in the first place?
In my opinion it failed in the first place because a lousy endo was done.........
Lastly, are you not concerned about possible vertical root fracture of the distal root (due to presence of a post associated
with a very minimal ferrule)? 
No, I am not concerned about a possible root fracture, according to the below mentioned papers, you can reinforce a weakened tooth
with composite.
This is in agreement with my clinical experience, for what this is worth....:-))
•Reeh et al. 1989, Trope et al. 1985, 1986, Rabie et al. 1985:  Intracoronal acid-etched bonded resins can internally strengthen
endodontically treated teeth and increase their resistance to fracture
•Hernandez et al. 1994, Ausiello et al. 1997 : New generation dentin bonding systems can strengthen rct teeth to levels close to
that of intact teeth
I will keep you informed about the follow-up! - Marga 

Marga, thank you for your reply. I'm glad to hear that you've had good experience with such cases, and above all, it's great that
most have worked over the long-term, at least in your hands. This just goes to show that clinical experience, good treatment
planning and exceptional skills can successfully salvage even some of the most questionable cases.

I also agree with you that the case most likely failed because of the lousy endo, but I somewhat suspect that coronal leakage
(esp on the mesial--at least radiographically), may have also contributed to failure. Again, I wonder if flexure ('bending') of the
bridge in this part of the mouth (where the mandible can flex to a certain degree, especially with a poorly designed occlusal scheme),
also added to the coronal leakage/breakdown. I guess all this is now irrelevant considering you've successfully rescued this
'damsel in distress':-)) Thanks too for providing references to support your anwser to my last question. I agree with the concept of
acid-etched intracoronal (and I guess, intraradicular) reinforcement, if that's what you were alluding to in your anwser. However,
I am still concerned about the gradual demise of the resin bond or seal in a shorter time, than a seal created by an amalgam core
for example. Finally, I'm also not sure whether your references specifically considered the issue of adequate ferrule, but if they did,
then you seem to have provided a good backing for your clinical observations when using this technique.
Thanks again for a great post and reply. - Peter

Hi Marga, Vaseline provides lubrication only (to all intents and purposes).

I use GC Fit-Checker, which will actually provide space.  This is desirable for the same reasons that the lab applies die spacer
to the dies. How do you accomdate the cememtn thickness with your technique?  Do you use air abrasion or some other means to slightly
reduce the size of the core you have built up?  I guess this might work, as well as have the advantage of getting rid of the Vaseline
(which may interfere with the cement bonding). Would you mind sharing the specifics of the technique that you use? - Ken

Hi Ken, Now I understand what you meant. I do use a sandblaster (in addition to alcohol), to get rid of the vaseline. You can expect
that it will slightly reduce the size of the core. Moreover, most composites have a polymerzation shrinkage of approximately 4%.
I see your point, but in practice, I don't have problems with seating the restoration after I made the build-up. - Marga