How to sprue?

[ParkwayDental]

We are making a sample and we will be pressing 7 units.

What would be the best way to sprue this bridge so it will press out?

And how many ingots would y'all suggest?

 

[PDC]

Tyler, hopefully you weighed you framework before you waxed it. To be sure of the # of pellets, this is a must. You have to weigh your sprue former, add the weight of the frame, and then subtract that total from the waxed and sprued bridge attached to the sprue former.

I feel pretty certain that 3 pellets which is the minimum for a 300 gram ring will press this. I would sprue the anteriors from the lingual at the incisal edge and bend the sprues back as you go towards the molars...you might even double sprue the molars (buccal and lingual) to be safe. The position on the sprue former will dictate how you have to form your sprues. Hope that helps!

 

[ParkwayDental]

We haven't weighed it yet, it's a wax overpress that I designed on 3Shape and it is removable. Ill have to weigh the framework and subtract that from the wax up weight once it is sealed. I'm guessing 3 ingots, and we will use a 300 gram ring.

Would you sprue every one? Or every other one?

 

[zero_zero]

Weigh the empty ring, then weigh with wax on, subtract, calculate 1.0 g ingot weight for each 0.3 grams of wax. You'll need at least a 300g ring or bigger, check with the ring sleeve to make sure will fit. Use at least a 6 gauge runner bar with 8 gauge sprues (6 ga at the terminal units),make sure all the connections are tapered well. Depending on thickness may need to doublesprue the molars. Center the whole thing well. Use a disposable plunger to avoid cracking. Depending on pressing furnace and material the hold time needs to be increased about 25%. Lower the stop speed to about 150 um/min if possible, or increase press time. If the furnace doesn't have crack detection keep an eye on it, while pressing.

 

[PDC]

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[desertfox384]

I would sprue like this picture just above, right to the base. I don't see a point for a runner bar.. if it was metal maybe.

 

[zero_zero]

I would sprue like this picture just above, right to the base. I don't see a point for a runner bar.. if it was metal maybe.

If is arching enough to hug the ring center there's no need for a runner bar, for straight long bridges its necessary to easily deliver the material to the ends...

 

[PDC]

We haven't weighed it yet, it's a wax overpress that I designed on 3Shape and it is removable. Ill have to weigh the framework and subtract that from the wax up weight once it is sealed. I'm guessing 3 ingots, and we will use a 300 gram ring.

Is that wax overpress a milled pattern or printed pattern? Looks like a time saver.

 

[ParkwayDental]

Is that wax overpress a milled pattern or printed pattern? Looks like a time saver.

It's a printed pattern. I don't think this could be milled? Basically just design full contour and at the end it will cut the overpress out around the margins and pontics. Just seal margins and under the pontics and good to go. It's a huge time saver, we really don't press but every now and then when we get backed up ill press a bunch to help get caught back up. It eliminates having and experienced waxer spend time waxing when they could be doing other things. The when designed the zirconia framework provides anatomical support to wherever it's need. Ill set a minimum of like .80 and it will cut the framework back to that distance.

 

[disturbed]

beef up joint areas. they are typically the most likely to mispress. no runner bar. i would spru to linguals so chance of discoloration is minimized. but yes, pdc has provided a good pic for you. make certain thin areas are beefed up for pressing. your margin areas look very thin. you can always releave the bulky areas after press. i would at least do a minor cutback. these can look HOT with a little layering. zr will show through if you don't have at least 1.5 mm with LT. i prefer mo with some layering. i charge extra if i layer.

 

[ParkwayDental]

beef up joint areas. they are typically the most likely to mispress. no runner bar. i would spru to linguals so chance of discoloration is minimized. but yes, pdc has provided a good pic for you. make certain thin areas are beefed up for pressing. your margin areas look very thin. you can always releave the bulky areas after press. i would at least do a minor cutback. these can look HOT with a little layering. zr will show through if you don't have at least 1.5 mm with LT. i prefer mo with some layering. i charge extra if i layer.

Ya I gotcha, this has not been sealed yet around the margins causing it to look thin in the picture. When we seal the margins we leave them bulky and them take them down during finishing. The wax up is set for a minimum thickness of 1mm and I have 8 tenths of spacer under the wax up so I will be around 1.5 to 1.8mm of porcelain thickness. We will be pressing full contour with no cut back, I'll take some pics when we are done. We will not be using Emax Zirpress over this we use a different ingot!

 

[disturbed]

what ingot?looking forward to seeing pics. monolithic over zr is the only way to go IMO.

 

[ParkwayDental]

what ingot?looking forward to seeing pics. monolithic over zr is the only way to go IMO.

It is CZ Press from Glidewell, from what pressing we have done for just straight up shades they look pretty good!

 

[disturbed]

use a zir liner?

 

[ParkwayDental]

use a zir liner?

No zir liner

 

[sidesh0wb0b]

let us know how it comes out. better yet, pics!

 

[ParkwayDental]

Well it pressed out like a champ! 300 gram ring with 3 ingots and walla it pressed perfect. Just a little finishing and thinning the margins back out and its good to go.

I'll post more pics when it is finished all the way!

 

[Marcusthegladiator CDT]

Wow, with a runner bar, single spru on molars, and a skipped anterior. Nice.

 

[ParkwayDental]

Ok here are the final pics of the bridge. Just straight pressed monolithic CZ Press from GW.

 

[ts4341]

Tyler, great looking work., Zirpress HT pressed to Zr frames are sweet looking on the model and in the mouth! I've tried other labs printers and milled wax over Zr, and they never fit like Tyler's. T