Don’t Skip The Verification Step
For long span partially or fully edentulous cases involving implants, I always verify my model before making a definitive prosthesis. In my mind, anything more than two or three units would require a verification step. This is especially important when you are connecting the implants in your prosthesis…
Historically, there are many ways you can verify the cast. Personally, I like to ask the lab to pre-fabricate these verification jigs using individual temporary non engaging abutments with resins wrapped around them. I will try them on individually intra-orally and ensure they are fully seated and not touching one another. I will then connect them with just enough of the low polymerization shrinkage PMMA such as GC pattern resin to stabilize all the pieces together. Once they are connected together and set completely, you can remove them and send them as one piece to the lab. Or I can take a pick up impression along with the entire piece and send that to the lab.
There are other ways to verify the cast. Another common way is to connect the abutments using floss or wires and then connect them with a large amount of acrylic or resin chairside. This was common during the days of external hex connection implants. I don’t like this method because this is messy and has a lot of built in errors in it. The key is to minimize polymerization shrinkage so the less you use chairside, the less it will shrink chairside and the more accurate your jig will be. It does take more planning and time to fabricate. But to me it pays off in the end when the prosthesis fits nicely and the risk of prosthetic mechanical complications such as broken screws or broken prosthesis is minimized.
What do you use to verify your master cast? I’d like to know!
Thanks for reading.