21st Century Gold Crown

[Affinity]

haha look who comes sniffin around, mr goldfinger himself!

 

[CoolHandLuke]

i must have been right, he bought into a gold investment, or a metal supplier.

 

[corona]

jeez people , why not just wax those and cast . seems like so much waste. I dont see how that can be cost effective . unless its slm sintering or casting . corona

 

[CatamountRob]

jeez people , why not just wax those and cast . seems like so much waste. I dont see how that can be cost effective . unless its slm sintering or casting . corona

There isn't any waste if you are already a refiner, which, they are.

 

[Tom Mappin]

jeez people , why not just wax those and cast . seems like so much waste. I dont see how that can be cost effective . unless its slm sintering or casting . corona

Hi Corona,
Think about all of the things that can go wrong throughout the lost-wax process. There's spacer thickness on the die, instability of wax, expansion of investment, risk of porosity, risk of miscast, and a cast-able margin thickness in the tens of microns. And you need twice as much metal as the crown weighs for proper casting.

When we mill, we eliminate all of those variables and can mill to within the single-digit micron margins. And we didn't even mention the time factor. From start to finish it takes 15 minutes to cut 1 unit. A case could go from file to FedEx pack in a matter of minutes if the timing is right. Normal turnaround is 48 hrs. business days.

This is a vast improvement over what we can produce using the lost wax technique in both speed and quality. It also blends seamlessly into the new digital stream. Combo cases, milled gold molars and lithium di-silicate or zirconia bi's and anteriors can be produced in the same time-line.

You can get more answers here.

 

[corona]

Hi Corona,
Think about all of the things that can go wrong throughout the lost-wax process. There's spacer thickness on the die, instability of wax, expansion of investment, risk of porosity, risk of miscast, and a cast-able margin thickness in the tens of microns. And you need twice as much metal as the crown weighs for proper casting.

When we mill, we eliminate all of those variables and can mill to within the single-digit micron margins. And we didn't even mention the time factor. From start to finish it takes 15 minutes to cut 1 unit. A case could go from file to FedEx pack in a matter of minutes if the timing is right. Normal turnaround is 48 hrs. business days.

This is a vast improvement over what we can produce using the lost wax technique in both speed and quality. It also blends seamlessly into the new digital stream. Combo cases, milled gold molars and lithium di-silicate or zirconia bi's and anteriors can be produced in the same time-line.

You can get more answers here.

Hi Tom , yes i agree , a variety of things could go wrong throughout the lost cast wax process , IF you dont know what your doing .
But to turn that around , I could pose the same issues with cad cam.

I remember the days when i was wet behind the ears when it came to understanding procedures in ie> waxing full cast . Yes there were remakes at the beginning , but once you get the hang of things and work smart waxing,investing,casting,finishing a FC gold crown is elementary and predictable .

And as far as waste is conserned , a milled gold crown will have plenty (judging by those awesome pics of the gold pucks ) and yes if you can refine the scrap , but oh man that seems like ALOT of scrap . And what if the crown didnt fit or work for some reason ? That gold milled crown cant be remelted to refabricate another .... it would have to be scrapped . Why not just mill it in wax ? save on the burs and invest and cast ? Hopefully you would have a decent tech who knew how to invest and finish.

This is an excellent discussion and those gold pucks look beautiful Tom , its just not the way I would go , thats all .

. corona

 

[rkm rdt]

Milling gold makes perfect sense .
I have tried cad cast where wax is printed and cast.

It's fine if you want to cast printed wax patterns yourself. You have control and can incorporate your own expansion preferences.

However cad cast as a service to labs does not work as well because all wax units are cast together.
This means one expansion for all.
This would be like giving you waxups to your tech to invest and cast and when you ask him for more expansion(or less) he tells you that he can't change the liquid/water ratio .

Milling gold means each file can be milled to the specific expansion parameters set by the cad tech.

That is why milling alloys makes perfect sense.

 

[CoolHandLuke]

Hi Tom , yes i agree , a variety of things could go wrong throughout the lost cast wax process , IF you dont know what your doing .
But to turn that around , I could pose the same issues with cad cam.

I remember the days when i was wet behind the ears when it came to understanding procedures in ie> waxing full cast . Yes there were remakes at the beginning , but once you get the hang of things and work smart waxing,investing,casting,finishing a FC gold crown is elementary and predictable .

And as far as waste is conserned , a milled gold crown will have plenty (judging by those awesome pics of the gold pucks ) and yes if you can refine the scrap , but oh man that seems like ALOT of scrap . And what if the crown didnt fit or work for some reason ? That gold milled crown cant be remelted to refabricate another .... it would have to be scrapped . Why not just mill it in wax ? save on the burs and invest and cast ? Hopefully you would have a decent tech who knew how to invest and finish.

This is an excellent discussion and those gold pucks look beautiful Tom , its just not the way I would go , thats all .

. corona

Corona. A gold crown that doesnt fit is still an investment in gold. Because it is milled and not melted to cast it can indeed be reclaimed and put in the smelting pot to make more gold pucks. The metal is not superheated this way and can be used repeatedly.

C hafner has been doing just that for 160 years; reclaiming jewelry. Making bars. Due to the differences in density smelted gold is easier to purify. Nickels and coppers rise to the top of the pot.

Casting gold is different. The process needs to account for sprues and separator and investment expansion and reaction layer and polishing. You cant reuse that stuff because of how it is treated.

Gold is not like zirconia when milled either. You dont get dust. You get swerf. It is cooled as it is cut which ensures the swerf is collected completely.

The process requires no finishing stage except to polish the cut connections.

If for some reason there is a fit issue the crown can be reclaimed. Or in the case of short contacts it can be electroplated.

 

[CoolHandLuke]

you probably watched Lord Of the Rings and saw Sauron cast the gold ring, with a red hot molten metal. this is how to improperly cast gold. this is also not how gold looks when it is cast, anyone who does casting will know.

it flows as gold, or should. red hot or white hot metal necessitates a degauss process post cast. extra time, extra impurity. burnt metal that must be ground away.

 

[CoolHandLuke]

Hi Corona,
Think about all of the things that can go wrong throughout the lost-wax process. There's spacer thickness on the die, instability of wax, expansion of investment, risk of porosity, risk of miscast, and a cast-able margin thickness in the tens of microns. And you need twice as much metal as the crown weighs for proper casting.

When we mill, we eliminate all of those variables and can mill to within the single-digit micron margins. And we didn't even mention the time factor. From start to finish it takes 15 minutes to cut 1 unit. A case could go from file to FedEx pack in a matter of minutes if the timing is right. Normal turnaround is 48 hrs. business days.

This is a vast improvement over what we can produce using the lost wax technique in both speed and quality. It also blends seamlessly into the new digital stream. Combo cases, milled gold molars and lithium di-silicate or zirconia bi's and anteriors can be produced in the same time-line.

You can get more answers here.

holy moly tom, single digit micron accuracy ?

 

[Tom Mappin]

This is an excellent discussion and those gold pucks look beautiful Tom , its just not the way I would go , that's all .

. corona

Thanks Corona! I can remember twenty-some years ago when I had my lab thinking to myself, "why would I want to press ceramic when I can produce a beautiful porcelain jacket crown on a platinum foil matrix?"

Which of these is easier to complete and why?

−5(1 − 5x) + 5(−8x − 2) = −4x − 8x

or

3 + p = 8


In all honesty, we all said the same thing... at first. Basically what we've done is consolidate the majority of those variables into our process and removed them from the labs' process. Now technicians can go from design to polish in 48 hours waiting time with zero risk of porosity or miscast, guaranteed. WYSIWYG dentistry. In the digital age I think everything we thought we knew how it should be done, is worth a second look to see if improvements can be made.

I can remember being totally engrossed in the blue copper-sulfate solution in the copper plating tank for the copper plating dies we used to fabricate. Then I remember being amazed at the epoxy model system. Things change, dentistry and dental technology is no different. We can't stop it. We can either join in or go sell tires ( as a friend told me recently).

What else would you expect a family of dental technicians and precious metal refiners do?

 

[Tom Mappin]

holy moly tom, single digit micron accuracy ?

I was going to say this anyway, but you just have to hold the finished product on the die or in the mouth and explore the margin. It is amazing.

 

[rkm rdt]

I like how you think Tom.
We owe it to ourselves and future techs to challenge orthodoxy.

 

[corona]

Thanks Corona! I can remember twenty-some years ago when I had my lab thinking to myself, "why would I want to press ceramic when I can produce a beautiful porcelain jacket crown on a platinum foil matrix?"

Which of these is easier to complete and why?

−5(1 − 5x) + 5(−8x − 2) = −4x − 8x

or

3 + p = 8


In all honesty, we all said the same thing... at first. Basically what we've done is consolidate the majority of those variables into our process and removed them from the labs' process. Now technicians can go from design to polish in 48 hours waiting time with zero risk of porosity or miscast, guaranteed. WYSIWYG dentistry. In the digital age I think everything we thought we knew how it should be done, is worth a second look to see if improvements can be made.

I can remember being totally engrossed in the blue copper-sulfate solution in the copper plating tank for the copper plating dies we used to fabricate. Then I remember being amazed at the epoxy model system. Things change, dentistry and dental technology is no different. We can't stop it. We can either join in or go sell tires ( as a friend told me recently).

What else would you expect a family of dental technicians and precious metal refiners do?

no doubt , you put dental tech and refiner together and yes i can see it throu your eyes . Its minds like yours that keep moving the cheese .
I just happen to like ( progressives will call me crazy) the whole process / procedures / hands on about this business . I like the fact that i have to get so many variables right to complete a process, Im old school in that sense , I guess i will eventually go digital ... maybe its time to upgrade my commodore 64 ? Prosperity to your company Tom . cheers . corona

 

[corona]

Corona. A gold crown that doesnt fit is still an investment in gold. Because it is milled and not melted to cast it can indeed be reclaimed and put in the smelting pot to make more gold pucks. The metal is not superheated this way and can be used repeatedly.

C hafner has been doing just that for 160 years; reclaiming jewelry. Making bars. Due to the differences in density smelted gold is easier to purify. Nickels and coppers rise to the top of the pot.

Casting gold is different. The process needs to account for sprues and separator and investment expansion and reaction layer and polishing. You cant reuse that stuff because of how it is treated.

Gold is not like zirconia when milled either. You dont get dust. You get swerf. It is cooled as it is cut which ensures the swerf is collected completely.

The process requires no finishing stage except to polish the cut connections.

If for some reason there is a fit issue the crown can be reclaimed. Or in the case of short contacts it can be electroplated.

yeah i hear you CHL. Im just an old analog tech . you click a mouse , i carve the wax . lets have a beer or two . good info .

corona