Hey there—
Hope you all had a great July 4th holiday! Took some time off but happy to come back with this banger from the PCSP Meeting in Newport Beach a few weeks ago.
If you haven't been, it's an amazing meeting with top notch speakers. This was my first time as a guest sponsor with Digital Arches (thanks Danny and Autumn!) The format is great: 30 minutes per lecture. So lots of content at a feverish pace! Next year it's in my backyard at the Nines Hotel in Portland, Oregon. All female speaker line up with lots of headliners.
I know last issue I promised content on failures but this was timely and important. Will revisit that!
Read to the end for a bonus gift (must for labs using 3shape and Straumann Core Bar process).
Gratitude Quote of the Day:
“Wear gratitude like a cloak and it will feed every corner of your life.”— Rumi
Full Arch Related Content from PCSP 2025
Lots of great content, but I am distilling into two main takeaways here.
1)Dr. Marta Revilla-Leon's lecture on scan body comparison and accuracy was thrilling. If you were there you know what I'm talking about. I've been a Marta fan boy for many years as she's been at the forefront on research regarding full arch prosthetics. The first important thing she did was revamp the vocabulary we use to describe the different scan body systems which was much needed (and much better than grouping them all into "grammetry"). Here's her classification of the 5 types used for an all digital workflow:
Non-splinted scan bodies - standard MUA scan body
Non-calibrated splinted scan bodies - scan bodies connected with a non-calibrated framework to help with scan processes. This encompasses any framework milled or printed and then scanned in the mouth.
Calibrated scan bodies - these scan bodies were measured after fabrication and scaled to account for manufacturing error. These include most photogrammetry scan bodies like iCAM bodies. Also includes Tru Abutment IO Connect and Nexus as well as intra oral photogrammetry.
Calibrated frameworks - any framework which is designed, fabricated, and then rescanned using a desktop scanner before being utilized in the mouth. The desktop scanner allows the technician to capture the actual geometry of the framework instead of relying on a theoretical STL file.
Reverse scan bodies - scan bodies that screw into the intaglio of a temporary such as Straumann RevEX.
*Optisplint is sort of outside the classification because it allows a verified master cast to be produced which is technically a hybrid workflow. She did mention this during her talk and said "of course it works because the model is poured from the jig" lol.
While her recent paper didn't have accuracy data published, she did present initial findings at her lecture and here is a brief summary:
Calibrated scan bodies via extra oral photogrammetry were the gold standard for accuracy (iCAM, Pic). Intra oral photogrammetry via Shining 3D was comparable. Calibrated scan bodies via intra oral scanners had a broad variation on accuracy due to scanner types. Calibrated frameworks also showed consistent results. I think that the calibrated frameworks would work great for direct to fixture cases because at the moment we don't have a way of digitally collecting records for these cases without physical verification. Reverse scan bodies depended too much on the accuracy and integrity of the provisional.
2)Dr. Markus Blatz discussed zirconia bonding protocols and while his lecture wasn't specifically full arch targeted, it did help answer a question I've had for a while: are our ibar cases (internal titanium bar with cemented zirconia sleeves) at risk for debonding? If so, when? How can we prevent it from happening?
The current literature is minimal with limited follow up time. Makes sense because this whole ibar thing has only taken off in the past few years. This is the only paper I could find on it:
It's only 12-20 month follow up on 31 cases. None of the cases reported debonding but strangely two cases reported fracture lines in the zirconia suprastructures that "didn't require any intervention". Wut. Anyway, not exactly literature you want to use to make anyone feel better about these cases debonding spontaneously.
Dr. Blatz showed an article that I think is great long term evidence of this bond. He showed 15 year data on a prosthesis that I never expected to be true: the anterior zirconia Maryland bridge!
The article reviews 328 of these zirconia bridges that were all minimally prepped with a veneer design of the retention wing and all were bonded in the anterior maxilla. Follow up was from 2001 to 2022. Legit data! The 15 year survival rate of these is.......97.3%!!! That's insane. This might be a stretch, but my logic tells me if this can last for 15 years then a full arch bonded to zirconia should do the same. Maybe there are other confounding factors such as occlusion and passivity/strain on the bar, but for me this is encouraging and a good base line to defend the ibar debonding concern.
What about zirconia bonding technique? I recently observed a technician in a different lab cement a zirconia sleeve to a titanium bar without sand blasting the bar. He simply applied primer and then cemented. I asked why he didn't and he replied that the sandblasting didn't add any retentive element to the bonding. He's not entirely wrong, but Dr. Blatz shared this article:
The summary was the sandblasting is most predictable method to decontaminate a surface for cementation, which we know is critical for bonding (especially elements that don't have retention like our titanium bar and zirconia sleeve). Additionally, the time between sand blasting and cementation does have an effect on the bond strength (even after 15 minutes) due to contamination from air bone particles. Meaning, it's critical to sandblast and cement immediately to maximize the bond strength for that prosthesis. Don't sandblast your bar then go poop, take a lunch break, and then come back and cement it. Certainly don't go home and cement the next day.
VIDEO BONUS:
We frequently of questions about designing a zirconia sleeve on a predesigned bar via core file. An example would be the Straumann Core Bar workflow where they will design the bar from the full contour design and send it back to you to design the zirconia sleeve in a split file fashion. Many users have 3Shape which I don't use. Luckily we collaborated with our good friend and fellow technician Marisa Notturno from New York who was kind enough to record this 3 minute video showing how to set up and design the case in 3Shape. Give her a follow @marisanotturno:
Straumann Core Bar 3Shape Workflow
That's your five minute boost (maybe slightly longer than normal)! Next week's topic: pros and cons of bar/sleeve design in blender for dental vs. Real Guide.
-Charles
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