Casting long span bridge

[Principefly]

I'm curious to know if, when you need cast a long span bridge , extending from molar to molar, you connect with a bar the last two teeth.
According to your opinion, this helps to prevent distortion during baking of ceramic and other possible benefits of the casting's precision ?

 

[martintay]

Yes it is a good idea. I`ve even asked the dentist to cut it away after cementation to avoid "stress springing " ( i thin the connections first so he only has to make a small cut )

 

[Principefly]

No new opinion?

 

[rkm rdt]

Why not cast it in sections and then laser weld?

 

[Car 54]

Yes, or use interlocks, that way if something happens to a side (or depending on a known weak abutment etc),maybe you could put the male on that side to facilitate a possible future partial (or in these days it could be implants filling the void). I personally wouldn't do it in one piece, as I couldn't get it to come out without a warp, except maybe in getting a scanned wax up. But especially in my case, in doing that much porc. work in one "unit", I could never control it build up and moisture wise, to get the results I would be looking for.

 

[Principefly]

Everything you write is perfectly correct .. but unfortunately sometimes we do not make the choice, but rather the doctors!

 

[lcmlabforum]

You can tell them doctors they are crazy and go fly a kite/jump off a plane instead.
Just kidding.
LCM

 

[Principefly]

Good idea, next time I'll bring them to make a nice tandem flight with my paraglider

 

[Marcusthegladiator CDT]

Thats what precision attachments are for.

 

[adamb4321]

long span bridges are always going to be prone to flexing when the ceramic is fired, if you absolutely must have a full arch in one piece that actually fits properly I would look at making it in three or so sections and post ceramic soldering after a try in and preferably get the dentist to do a pick up imp using impression plaster in a custom tray that is very shallow. It's a bit long winded and, yes, furnace soldering can be a scary thought but it does work really well.

Or make it in zirconia, it doesn't seem to flex like metal

 

[Bobby Orr ceramics]

I disagree with all....... if you have a stable wax frame, proper sprueing to eliminate porosity, no bar joining molars and proper ceramic CTE to alloy...... there should be no reason to dance around the landmines described above.

We have never had to post solder segments, join molars, etc. .... when all those factors line up properly.

 

[Car 54]

Wonderful, glad it works for you, but that's you, and not me. Thank goodness there's room here for options, and opinions, for what works for us (me),and in our (my) hands and comfort zone

edit: and for me, in my world, nothing ever (all those factors) lines up..case in point, lol http://dentallabnetwork.com/forums/f7/how-have-you-lost-found-crown-you-were-working-14270/ Murphy's Law is a personal friend of mine.

 

[adamb4321]

I disagree with all....... if you have a stable wax frame, proper sprueing to eliminate porosity, no bar joining molars and proper ceramic CTE to alloy...... there should be no reason to dance around the landmines described above.

We have never had to post solder segments, join molars, etc. .... when all those factors line up properly.

Lots of ducks to line up to get that fitting straight from devesting, can you post some images of a full arch frame that you've made so we can see your design?
doesn't need to be on a model just would like to see how thick the connectors are.

 

[Car 54]

Let alone before divesting, like waxing the connectors in what process and with what, and the sprueing technique, I would like to know that one too. As sometimes, I can't even get a 6 unit pier abutment case to wax and cast without a slight warp. Thanks, Bobby