Post-Core-Buildup Technique By Thomas W. Mitchell, DDS, FAGD

Introduction: 

Here's our recommended post-core-buildup procedure.

Thomas W. Mitchell, DDS, FAGD
This is #19. This actually was a re-treat of a Romanian endo. We had that done after the composite buildup I did a few years ago fractured. That's the endo's cavit in the access.
Thomas W. Mitchell, DDS, FAGD
Endo left post space for me in the distal canal. A post here may be unneeded, but years ago I got tired of nice crowns on endo teeth showing up 3 years after completion fractured horizontally and unrestorable, so I began bonding fiber posts into most endo'd teeth. Pretty much stopped that problem for me.
Thomas W. Mitchell, DDS, FAGD
This is the "pre-drill" and the "size 1 drill" from the post kit. I've used these posts exclusively since 2000. I've only had 4-5 debond/break/fail.
Thomas W. Mitchell, DDS, FAGD
Once I know what size post I'm using the post is coated with Surpass 2. An option is to start by micro-etching the post with bicarbonate as suggested by Dr. John Kanca. I don't have that for my sandblaster so I skip that step.
Thomas W. Mitchell, DDS, FAGD
Then my assistant blows off the solvent of the Surpass 2 and light cures it. Now the post is ready to go.
Thomas W. Mitchell, DDS, FAGD
Next step is to prep the distal canal and chamber with Surpass 1,2,3 Universal Adhesive. It's important to use paper points to wick excess out of the canal after each application, especially after applying #3. Then before adding light I always try the post in the canal to force out any puddle of Surpass #3 resin that might have built up.
Thomas W. Mitchell, DDS, FAGD
Then I fill the canal and chamber with WO Anchor by Apex Dental Materials, seat the post into the canal and light cure it for 10 seconds.
Thomas W. Mitchell, DDS, FAGD
Then my assistant holds the post with a hemostat while I cut the post. Then I add more light since I couldn't get the light close to the Anchor cement before I cut the post. As you can see I'm leaving some of the old build up in place. I did that a few years ago so I know what that is (Exquisite Restoration Composite with Surpass 1,2,3.) If I hadn't done that bonding myself I would have removed it.
Thomas W. Mitchell, DDS, FAGD
Final prep ready for impression. There's a Class 1 furcation so I fluted the buccal from the gingival to occlusal, removing any hint of a "tunnel" at the furcation. I always add mesial and distal grooving, here as box forms, to increase resistance/retention. Zirconia crowns especially need extra grooving due to the inaccuracy of the milling process.
Thomas W. Mitchell, DDS, FAGD
This is 3M Imprint 3 Quick which I've been using since it first came out. Great material with no distortion problems. I inject medium body (that's the pink stuff) with heavy body in the tray. We joke that I only miss one impression a year so I try to do that in January.... Actually I rarely do need to take a 2nd impression.
Thomas W. Mitchell, DDS, FAGD
I prep plenty of resistance/retention form in all my preps especially zirconia since the cad-cam process is significantly less accurate than the lost wax or pressing process.
Thomas W. Mitchell, DDS, FAGD
I treat the internal of zirconia crowns first with Clean and Boost and then I sandblast the internal.
Thomas W. Mitchell, DDS, FAGD
The final result has closed, almost undetectable margins with contours following the prep contours especially at the buccal furcation.

Conclusion: 

I use posts not just to help retain buildups, but also to add strength to the prep, which helps prevent horizontal fracture. This technique gets a thin resin bonded to the post (the resin in Surpass 2) so we don't increase the thickness of the post, and gets resin bonded to the canal and chamber walls. Then the whole internal of the tooth with the post about 1/2 way down one of the canals is a "uniblock" with some flexability due to the elastic quality of the post and the composite. May be a bit controversial but in addition to this technique helping to retain buildups, it's also reduced the number of horizontally fractured endo teeth significantly for me. Hope this helps.

Case by: 

Thomas W. Mitchell, DDS, FAGD

Email: 

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