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Figure 3: Turning the impression, we can see that the prep was in contact
with the tray — another no-no. As hard as it may be to believe, all it takes
is one point of contact like this between tray and prep to prevent the entire
bridge from seating properly.
Figure 4: The impression itself around the splinted abutments is so-so;
tooth #29 appears to have a void on the facial and the lingual margins,
while tooth #28 has some very thin material on the facial and distolingual
margins. This always makes me nervous as we pour the die stone because
the material is heavy enough to bend those margins.
Figure 5: The margins on tooth #31 also appear thin and friable, and it’s
hard to tell definitively whether tissue retraction took place. Using the twocord
impression technique, or to a lesser degree by using a diode laser, we
can create enough lateral retraction to end up with a big, thick margin on
the impression that won’t distort.
Figure 6: As I flip the impression over, notice that we are missing the second
molar opposing the bridge and that the first molar is the most distal
tooth. You may recall that we are missing the first molar on the lower arch
as well, which is going to make it more difficult to verify a correct bite.
Figure 7: Here is the poured model of the impression. It looks like we have
enough reduction for the BruxZir ® bridge (Glidewell Laboratories) the doctor
prescribed, except for on tooth #28 perhaps. I would have prescribed
a PFM bridge, but that is another story. I am still concerned about the bite
because there aren’t any stops distal to the bridge.
Figure 8: When I spin the articulator around and view the case from the
anterior, my fears are confirmed. I have a hard time believing that the bite
from the impression is correct. I cannot believe that the patient only bites
on that cuspid. Without any unprepped teeth on the opposite side to hand
articulate, the situation looks dicey.
40 www.chairsidemagazine.com