11 unit bridge Milled CoCr

[Labwa]

I have a client with an 11 unit bridge.
hes keen on metal but i dont want to cast the thing.
I know traditionally i would have waxed a bar across the back of the arch of the bridge to keep it from warping then cut it off after i finished the porcelain work but do i need to give a milled CoCr frame the same type of support? I know its more rigid than gold alloy but i dont want to find out the hard way with this one.
cheers guys.

 

[DMC]

In August we will be milling metal. I don't know if we make profit or not, but we will try.

I hate casting N.P. and trying to fit big bridge.

Most labs feel the same I think?

 

[Labwa]

dentists still want it for the time being it seems.
I hate casting anything big. Too much alloy for the sprues. flexing, warping. headache!

 

[arnie16403]

I'm sure I'm a little late to respond to this, but you don't need a support across the back of the bridge. It's something you need in Zirconia but not in any type of metal, titanium or CoCr

 

[corona]

I'm sure I'm a little late to respond to this, but you don't need a support across the back of the bridge. It's something you need in Zirconia but not in any type of metal, titanium or CoCr

have to disagree with you on that . isnt it the opposite ....you WANT to have a support bar for metal and you dont need one for zirconia .... please explain a little more arnie .. thanks

 

[Gru]

It should be noted that cast and milled CrCo respond to firing differently. There is no tension in a milled bridge. If it fits after milling, it will fit after porcelain application unless the framework design is poor, or the CTE between the CrCo and the porcelain is off. I have done many large span bridges of both (cast & milled) and the milled have never warped. I have never done anything to a milled bridge "support" it. Note: I am only addressing CrCo.

 

[DMC]

Arnie may be cornfused as to what we are talking about.

I do not think he has Porcelain experience.

Maybe talking about some other shape for milling or sintering.

Interesting topic about milled vs/ cast metal warping in the furnace.

Sounds like it makes sense?

 

[Labwa]

im going to laser weld to be sure i think.

 

[Drizzt]

Are you going to have it milled ? If you do so why laser weld it ? You will add energy-tension to something that is energy-tension free . I have done some milled 8 units+ bridges with no problems at all .

 

[Labwa]

yeah its already milled. I hope you're right!