The sleeve that was placed in bridge in place of tooth no. 12 now acts as a stopper.
The stopper doesn’t have a screw channel and it cannot be screwed to the Multi-unit, it sustains vertical forces nonetheless.
Undercuts were made with a conical burr in the bridge for the cementation process of the sleeve.
The small undercuts increase the retention of the cementation procedure.
Using a 1.5mm sleeve as a stopper can be for aesthetic reasons as well as for strengthening the bridge.
Tip: it is easier to make cuts in zircon before Sintering while the material is still soft.