Is there a problem blasting emax with aluminum oxide?

designasmile

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I have always blasted emax crowns with aluminum oxide with no problems. Others I have talked to are doing the same.
Ivolclar says not to use alminum oxide on emax. Has anyone had a problem with, and does anyone have a reason for
Ivoclar's statement. When contacted, Ivoclar doesn't seem to know why alluminum oxide should not be used.
 
Car 54

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I've been using 50 micron for years, with no problems. Haven't had any come back with bond or crack issues, so I'm not sure what their concerned about? Unless they want to guard from labs that may use to high of a pressure, and blast the margins off, and Ivoclar doesn't want to get the "why are my margins pressing short" calls?
 
Tayebdental

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I have always blasted emax crowns with aluminum oxide with no problems. Others I have talked to are doing the same.
Ivolclar says not to use alminum oxide on emax. Has anyone had a problem with, and does anyone have a reason for
Ivoclar's statement. When contacted, Ivoclar doesn't seem to know why alluminum oxide should not be used.

I use Al 2 O 3 to divest, but I use glass beads on the emax itself, I think the Al 2 O 3 particles as we all know is very jagered, sharp and irregular and could creat creators that are full of micro crack that could affect the integrity of the restoration beside emax is glass not aluminum oxide( lithium disilicate) . Glass beads on the other hand has a uniform spherical shape that is less aggressive ( kider and gentler) when strike the surface, it polishes rather than create jagered surface. I hope I helped!!
 
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2thm8kr

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In the instruction manual it clearly states to blast with AlO3 at 1-2 bar pressure on page 28. It was explained to me by Ivoclar's glass engineer that ALO3 damages the surface on the intaglio surface of the crown creating a
weaker surface to bond to after etching. I think the key here is moderation and keep the blasting pressure low.
 
Tayebdental

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ai1281.photobucket.com_albums_a505_postpics16_7683712000500c1e9c2731b34b31fd01_zps2daa325c.jpg

And on page 26 this what they say,,:confused:
ai1281.photobucket.com_albums_a505_postpics16_7683712000500c1e9c2731b34b31fd01_zps2daa325c.jpg
 
Marcusthegladiator CDT

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I use both, aluminum oxide just does a better job. But just the initial divesting. Once Im close and the crowns are exposed, I use glass beads.
 
PCDL

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Yes... this is correct. if you use AL2O3 on your eMax, you will throw the earth off its axis and we will all go hurtling into the sun....

Of course, that being said, I use 110 micron AL for my main divesting, and glass beads on the crowns themselves.
 
designasmile

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I see P 28 says to use Al2O3 to remove the reation layer, but back on P 26 for divesting to only use glass beads and not use Al2O3.I have always used Al2O3 for everything with no problems to my knowledge. I have a Dr who has started
to mill his own emax and is being told by Ivoclar not to use Al2O3, and I'm telling him I use it all the time to clean
up the crown and prep the surface before staining.
 
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martintay

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They want to sell lots of "Invex" Liquid !!
 
Gru

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I see P 28 says to use Al2O3 to remove the reation layer, but back on P 26 for divesting to only use glass beads and not use Al2O3.I have always used Al2O3 for everything with no problems to my knowledge. I have a Dr who has started
to mill his own emax and is being told by Ivoclar not to use Al2O3, and I'm telling him I use it all the time to clean
up the crown and prep the surface before staining.

There was an article some time back that said Al Oxide blasting weakens the crown, as does etching too long. Didn't have any info on to what extent. Forgot where I read the article.

If your Dr. is milling blue-blocks, DON'T blast them! A light pre-sinter coat of crystal stain will make a nice layer to stain and glaze. Pressing? Never personally saw any problems, and the manual IS contradictory.
 
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martintay

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Also heat generation from Al ox if pressure is to high - keep it low !
 
Car 54

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In my case, I finish 100% of my copings and frameworks down, I intentionally wax them slightly bigger, to hand finish them down with Redberries and Bluberries (Wagner Rotary Instruments) which takes care of any surface contradictions, and reaction layer surface texture. I use 100 micron Al203 to divest the main investment off, then the 50, as I figured it gets into the nooks and crannies better. Maybe I should at least try staying with the 100 micron size throughout.

On page 35 of the green manual, it says to prepare the surface for veneering with Al203 at 1 bar (15 psi). When using Alumina Oxide, it sounds like the key is to keep the pressure low.
 
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Bobby Orr ceramics

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After I repress all my ingots, I blast with al oxide at 60 psi. Gives a nice passive fit !!!!

I also have some waterfront property in Kansas for sale if anyone interested.
 
2thm8kr

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How much for the property?
 
Car 54

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After I repress all my ingots, I blast with al oxide at 60 psi. Gives a nice passive fit !!!!

I also have some waterfront property in Kansas for sale if anyone interested.


lol, I laid that one on my Ivoclar rep before, needles to say, he didn't smile.
 
Tayebdental

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"hand finish them down with Redberries and Bluberries (Wagner Rotary Instruments) which takes care of any surface contradictions, and reaction layer surface texture".

Car 54,
they told me at Ivoclar not to grind the reaction layer, it should be eliminated by the invex liquid and sand plasting. I was able to minimize the reaction layer to almost nothing by lowering my high temp and short pressing time. It worked without buying ivoclar's " state of the art furnace ".
 
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Car 54

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Sorry friend, if that didn't post right. I do that after the Invex/blasting reaction layer process, as I just want to make sure the surface has been totally gone over afterward.


edit: by the way, thanks for nice tips on what you found to minimize the reaction layer.
 
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disturbed

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.......read the directions...
al ox.jpg
 
JPA

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Where can I get the Emax directions book? Thank You.
 
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