I have installed this DTU bridge (pictures below) in
Dec. 2002 and still it is working.
(DTU stands for: Dabiri Tehran University)
The case below was an ideal case for a DTU bridge. Also the Maxilary
first premolar had an old Amalgam filling that I could use as a DTU
As you see on the picture below, I have removed the Amalgam filling
to use it as a DTU key box. There is an important point here; I
finished cutting the Maxilary left Mollar But befor getting my final
impression I have partially filled the premoler by composite!
This way I made a shalow depth composite filling that the further
DTU rest should lay over it.
On the pictures below you see the DTU metalic frame, my lab
technician has made.
Always I ask my lab to block out any possible overhang on the key
rest cavity thus the DTU rest/key should easily get sit on its
I checked the frame on my patient teeth. it easily got sit.
Already the DTU rest, you see on the pictures above, almost looks
like an inlay but this is not what I want, I do remodel the rest.
Always I reduce the size of the key/rest by a cutting disk. On
Buccolingual direction and also from ending side of the key, I
always reduce the metalic key size to be sure the second layer of
composite fuses with the first layer! I should sandwich the
DTU key among two layers of composite!
In fact, after that remodeling, the metalic rest should look like a
loose key inside the abutment cavity. See the pictrue below;
The bridge above is ready for cementation.
I do clean the Premolar box carefully then add a very small drop of
self cureing glassinomer cement on the cavity floor, while my
assistant fills the crown with a proper cement (we should move
fast). Immediately I should install the DTU bridge on the teeth then
I remove the possible excess glassinomer by a proper tool (instead
of that selfcure glassinomer, also we can use a very small piece of
"Dual cure or selfcure" composite but we should have etched the
cavity before). after cementing the bridge on the teeth, the last
stage will be full filling the premolar by composite, or we must
completely cover the metalic rest by comosite!
See the finished DTU bridge, on the picture below;
The Post Op Panorex.