Updated strength on milled emax

[Kam Yu]

So, i saw that milled emax is now being advertised as stronger than pressed. Is this really the case? I have heard many people complain that the fits are bad and also they crack easily in the lab. Im interested in milled emax or comparable material. Can anybody update me on the current quality of milled emax?

 

[HygienicBee]

In my opinion milled emax is better than pressed visually, the shades are more accurate and the fit is great as long as the nesting is done properly. As for strength I think milled is stronger but I do not have the facts to back it up.

 

[2thm8kr]

We have at least 10k in service. If you follow the recommended minimum thickness they last. Avoid on knife edge preps or crappy preps in general.
Prep design make a huge difference.

Don't use carbides to cut in your anatomy. Don't get the material excessively hot with silicone wheels working on margins or polishing.

Emax is hard on spindles.

 

[Patrick Coon]

Hi Kam Yu,

The strength of e.max has not changed, just updated the testing to reflect what other companies are doing (different versions of the flexural strength that are allowed by the ISO standard). With these new tests, the milled version actually comes out with a little higher Biaxial Flexural Strength. Fracture toughness is not changed (that test is set in the ISO standard) and they are basically the same for pressed and milled.

As for fit and margin quality, that is more defined by the mill, grinding strategies, and following the manufacture's guidelines for minimal thickness requirements and prep design.

Cracking in the lab can be caused by several things, including sharp prep designs and uneven thicknesses. We get these in the pressed version as well, but most labs will use die spacer to round sharp edges, and have added slow cooling to to make sure that everything cools evenly to compensate for the thick-thin-thick (uneven thickness) issues. You can do the exact same things to take carre of these in the milled version.

 

[Kam Yu]

Hi Kam Yu,

The strength of e.max has not changed, just updated the testing to reflect what other companies are doing (different versions of the flexural strength that are allowed by the ISO standard). With these new tests, the milled version actually comes out with a little higher Biaxial Flexural Strength. Fracture toughness is not changed (that test is set in the ISO standard) and they are basically the same for pressed and milled.

As for fit and margin quality, that is more defined by the mill, grinding strategies, and following the manufacture's guidelines for minimal thickness requirements and prep design.

Cracking in the lab can be caused by several things, including sharp prep designs and uneven thicknesses. We get these in the pressed version as well, but most labs will use die spacer to round sharp edges, and have added slow cooling to to make sure that everything cools evenly to compensate for the thick-thin-thick (uneven thickness) issues. You can do the exact same things to take carre of these in the milled version.

So pretty standard protocols. We follow all those rules with our pressed emax. Is there any literature i can send to my clients as far as strength?

 

[Kam Yu]

So, who does a great job milling these? Ive heard great things about straumanns blue block milling.

 

[2000markpeters]

I mill them everyday on my Dyamach DT2 mill. Great results however milling times are high to get good results (50 minutes) I only mill them at 60% feed rate and use diamonds and lots of coolant.

 

[2000markpeters]

Same applies to Suprinity from Vita

 

[Kam Yu]

I mill them everyday on my Dyamach DT2 mill. Great results however milling times are high to get good results (50 minutes) I only mill them at 60% feed rate and use diamonds and lots of coolant.

Id like to see a nice result.

 

[Patrick Coon]

So pretty standard protocols. We follow all those rules with our pressed emax. Is there any literature i can send to my clients as far as strength?

 

[Brett Hansen CDT]

Patrick, do you know how long it takes to mill a single emax with the PM7?

 

[Patrick Coon]

Patrick, do you know how long it takes to mill a single emax with the PM7?

Depending on geometry and size, it runs between 30 and 45 minutes.

 

[Kam Yu]

Can anybody refer me to a lab that does high quality emax milling for other labs?

 

[2000markpeters]

where are you located

 

[Kam Yu]

where are you located

Washington state

 

[Patrick Coon]

Can anybody refer me to a lab that does high quality emax milling for other labs?

I would try Core3D. They mill with our mills that have been fully validated for e.max, and should do a good job as long as the designs are appropriate.

 

[RileyS]

aren't doctors whipping these puppies out in 15 minutes on their chairside mills?

 

[Patrick Coon]

aren't doctors whipping these puppies out in 15 minutes on their chairside mills?

Yes, 12-20 minutes on a chairside mill, but these are different machines and made to do this one thing well, or they have more than one tool cutting at the same time.

 

[grantoz]

i think you should also look at gc lisi press we have been using it a lot lately not one of my clients has requested to go back to emax .we find the colour is better and less chippy on fine margins which is just about all veners the other thing i like is no reaction layer we just mill the wax and then press the fit is great and your burs last for ever.