Verification jigs are prosthetic devices that are used to confirm the precise position of the implant analogs on the master cast, thus ensuring a passive fit on the final prosthesis.
There are multiple materials and techniques to fabricate the verification jig: poly methyl methacrylate, resin or plaster, the fabrication of the jig can be performed on a master cast or intraorally.
The use of plaster as a verification jig has the advantage of being an easy, fast and cheap material, but the most appealing characteristic is its brittleness. Therefore, once it's fastened to the implants intraorally, it will break if it is not accurate.
This visual essay will walk the reader through the basic steps of fabricating and trying on a plaster verification jig:
Master cast of four tissue level analogs with soft tissue moulage.
Wax matrix to hold the plaster while setting, the plaster is poured over the temporary cylinders.
Front view of wax matrix on the master cast.
Front view of the plaster verification jig on the master cast.
Lateral view the plaster verification jig. Note the thickness of the material is kept to a minimum.
Plaster jig on a mirror. Note the distance kept between the platform of the temporary cylinder and the jig allowing space for the soft tissue.
Jig fastened to the implants. One screw test is performed to confirm passivity.
Radiographic verification of the temporary cylinder fully seated on the implant platform.
CARES milled titanium bar on the verified master cast.
Front view of the milled titanium bar on the master cast.
Intaglio surface of the milled titanium bar.
Front view of processed and polished implant hybrid prosthesis on the master cast.
Intaglio surface of the processed and polished implant hybrid prosthesis.
Front view of the implant hybrid prosthesis intraorally.
Occlusal view of the implant hybrid prosthesis intraorally.
A step-by-step technique of how to fabricate and try-in a plaster verification jig to ensure accuracy of the master cast has been shown. This technique allows for a cheap, fast and predictable way of confirming the precision of the master cast.
It is recommended to go through this process prior to fabricating any full arch prosthesis case.
Ricardo Mitrani, D.D.S., M.S.D., is a member of Spear Resident Faculty.