(Help!) Multi-Unit bridge issues.

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richgreen

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On a bridge this small it would seem unnecessary to place a sintering connector. However. one consideration could be, in this case, the abutments are thinner and have more surface and will cool faster than the pontic. A connector can help control the heat rate as the bridge heats and cools, thereby helping to control unwanted movement. I use a sintering connector on bridges like this that looks like a runner bar on a casting ( I know that ages me but, eh) And like Car54 mentioned perhaps a slower cooling rate might help
 
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omsk

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Could it be a path of insertion problem during design?
Maybe the path of insertion is not being selected as a bridge but as single units.
 
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NDA

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Sorry I thought you were sintering sintered chrome restorations.For zirconia you do not need stabilizer bars. Use very small beads and place on top without sinking. We do full arches of zirconia like this without problems
sooo... Does that make a difference? Sinking the bridge into the bridge or not?
 
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NDA

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On a bridge this small it would seem unnecessary to place a sintering connector. However. one consideration could be, in this case, the abutments are thinner and have more surface and will cool faster than the pontic. A connector can help control the heat rate as the bridge heats and cools, thereby helping to control unwanted movement. I use a sintering connector on bridges like this that looks like a runner bar on a casting ( I know that ages me but, eh) And like Car54 mentioned perhaps a slower cooling rate might help
Sintering connector? Is that same with a stabilizer?
 
deadhead

deadhead

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we used to have this issue on our bridges too. Tried everything from stabilizer bars and editing our sintering times. nothing worked, then we milled out of wax and still had an issue with fit. bridge fit perfect on each prep individual so we looked at design and found our problem. The designer was not setting the path of insertion right so when it was generating the NC file it was not compensating for under cuts of a bridge so our bridges would not fit. once we got our designer on the right page about path of insertion our fits have been perfect. We mill full arch bridges to 3 unit bridges with no stabilizer bar and havent had a fit issue since we ressolved our issue. hope this helps. When in doubt go back to design and check all parameters and path cause now a days if you use high end ZR stabilizer bars are not necessary. if you have a fit issue i would definately check your path and design parameters first before messing with sintering cycles and bars
 
JeffT

JeffT

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Is it possible that the cut scanning model is the possible cause? Maybe the dies are not seated fully during scanning, or there is movement of the dies in the modelling system you are using.
Just a thought.
 
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a3dl

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Also if your are doing multi die registration that your are calibrated on scanner and getting perfect stitching of dies to master model
 
Patrick Coon

Patrick Coon

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At the moment, we are trying to conserve materials and thought, instead of doing the kind of stabilizer the way it is in your pictures, we are thinking of leaving materials around the top and bottom of the bridge...
We'll see what happens.

View attachment 33470











Are you laying this bridge on the occlusion or on the facial or lingual? If on the facial or lingual, because of the curvature it will sag and the individual abutments will fit, but the bridge will not.
 
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grantoz

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I just have read the whole thread if you use Zirkonzahn dispersive and use the connectors and stabilizer that zirkonzahn recommend and providing you scan correctly ,it will fit perfectly you even have an m5 use genuine stuff you will get far less headaches. we mill full arches all the time they fit all the time but you need to follow the instructions.you must use a stabilizer.
 
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Iskander

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Are you using any stabilizer bar during sintering?
Hello,
I have a fitting issues with zirconia, but I don't know where is the problem, I print the same conception and it fits but when I mill it (I use Amann Girbach) it doesn't fit at all, the second problem is that it doesn't happen with all the conceptions, after milling two conceptions on the same zirconia the one fits and the other doesn't.
Please help I can't find any solution.
 
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