Acrylic partial try-in ... the process.?.

[Craig T]

I get several low income cases each year for acrylic partials that require a try-in to confirm tooth arrangement and bite. I have been using lucitone 199 repair material to fabricate a wrought wire clasped baseplate for the try-in. I then thin it out as much as possible after the boil out before processing. On some cases I can take a fissure bur and cut around the imbedded section of the wrought wire clasps to remove almost all of the cold cure prior to processing, but neither is ideal. Any suggestions on how to go about this a better way without processing wire clasped baseplates on dupe models?

 

[JohnWilson]

First don't try in the case with the clasps, it makes things way to complicated for a case like this. If retention is an issue you can use wax in the undercuts to hold things in to check the bite/esthetics of the arrangement

When the case comes back then make your clasps and process with a matrix. I like to use thick cyno glue to hold clasps in place on the dup, then fit everything back to the master.

 

[AJEL]

I make a duplicate model & make a baseplate on it out of Vynacron "Microfit VR-90 shade 93" ask Steve for it, Products - Vynacron Dental Resins, Inc. it is a vinyl reinforced acrylic that is a little flexible & strong enough to thin almost paper thin to do your set up on. This material can be hydrocoloid poured ratio 1.75 part powder 1 part milky monomer, 55*c 1 atmosphere 15 min. You can if you want to make a flexing valplast spur type clasp for retention during the try-in. I make wrought wire frames still (a 60's thing) and if only putting in a buccal clasp I would do it the same as JohnWilson. if you are careful the model you made for the baseplate can be used for the processing. If you are packing and heat curing these cases & don't want to do a lingual bar on the mandibular you might try the Microfit Type-II from vynacron, the 91 shade would be close to you rluci 199, you can add teeth and clasps to it latter with standard acrylic. With any Vinyl case prepair the teeth like for nylon (diatorics) and use Vyna Glaze to insure a bond.

 

[ottawa]

I use a lightcure baseplate and cut a channel at the area the clasp is going to be in acrylic. Soak the model in water and pour wax to secure the clasp and fill the channel. That way after boil out, you can take off the baseplate without breaking the clasp off the stone. It takes a lot more time to add clasps after try-in, because you may have to move teeth and wax-up again.

 

[Flipperlady]

Also a tiny dab of superglue will hold clasp in place.

 

[Craig T]

Thanks for the suggestions everyone. I have to try in the cases with clasps. I don't want the possibility of the Dr. fumbling around with a loose appliance or the patients first experience with the appliance to be compromised. I'm digging the light cure baseplate with channels for the clasps that are tacked in with CA. A combo of ottawa & Flippercentral.

 

[Flipperlady]

I love the lightcure baseplates. I just bought some of the Primobase sheets after using Triad denture material for many years. The new stuff is much harder to polish but the color is better and it's strong enough for a one or two tooth flipper. The Primobase is thin too.