FABRICATE OVERDENTURE TYPE B

Block out over the analogs on the model to allow some room for the healing abutments protruding through the tissue. Fabricate baseplate and wax rim on master model.  
1.
Order appropriate diameter, non hexed temporary cylinders from the pertinent manufacturer to make a verification index. Send base plate, wax rim and verification jig to doctors office for try in and VOD.
2.
Upon return of the verification index, base and bite mount the working models on a semi adjustable articulator. If the verification index was sectioned and reluted together by the doctor during try in, remove and reattach the misaligned analog to the model, using the verification index as a positioning aide.
3.
Set teeth in wax for try in. Send to doctors office for wax try in and new bite record.
4.
 After the wax try in is approved for esthetics and vertical dimension, remount the models and reset teeth as needed, make a putty index of the set up. Extend the matrix over the occlusal of the denture teeth. Cut back matrix through central fossa and incisal.
5.
Remove the matrix and the set up from the model. Determine AP spread and acceptable cantilever extension of the bar.
6.
Reposition the matrix on the model to verify adequate space for the bar and overdenture exist.
7.
The bar can be waxed and cast in a traditional fashion or produced through CAD CAM technology or scan models in house with a Procera scanner if available.
8.
If the bar is going to be produced through CAD CAM technology, send models and teeth in wax to a milling center. Go to step 20
9.
If the bar is going to be waxed and cast, order appropriate diameter non indexed UCLAs.
10.
Screw the UCLAs on to the model with laboratory screws. ensure each abutment is seated fully on the analogs in the model.
11.
Wax the bar pattern with prefabricated plastic patterns (Hader or Dolder) or free hand wax the connectors between the UCLAs. Incorporate any attachments (Locator, o-ring, Bredent a.o.) on to the bar. Leave a space of 1.5mm to 2mm between the tissue and the bottom of the waxed bar for hygiene access.
12.
Verify with the matrix enough bulk for the overdenture acrylic and denture teeth exists.
13.
Remove the wax bar pattern and the soft tissue mulange from the model.
14.
Reattach the bar pattern to the model and verify passive fit of the bar pattern on the model
15.
Sprue, invest and cast the wax pattern bar with precious metal. Do not use non precious metal as this will cause a galvanic effect and corrosion with the titanium of the implants.
16.
Divest the cast bar with care. Do not sand blast the abutment implant interface, use acid instead.
17.
Validate the cast bar seats passively on the working model. Use only one screw in a terminal abutment and hand tighten the screw. The should not lift up at the contra terminal abutment.
18.
After the bar is seated properly polish the bar using a second set of analogs to protect the abutment implant interface.
19.
Process the wax set up over the bar.