Zirconia vs e.max core??

[dentor2010]

Hey guys I have an upper left cuspid to restore with a full porcelain crown. The dentist asked me which is more durable an e-max ceram layered on Zirconia coping or on an e.max press coping??
Recently I attendend a presentation on e.max by Pia Meuller (CDT),and she said there is no study done comparing these two options. The only study she knows of , compares e.max ceram layered on Zirconia with Monolithic (Full Mass) e.max press, where e.max press exhibits much more durability.
the prep is very discolored so I have to use an opaque core, so it should either be e.max HO ingot or a Zirconia core. I know Zirconia gives me more space for layering, but the dentist wants to know which is more durable.
Can anyone help??

 

[TheLabGuy]

e.max layered coping is around 140 Mpa. in strength. Zirconia layered is right around that number if not a little lower. It's really what you feel comfortable with doing because the strength is relatively the same. Hope that helps.

 

[dentor2010]

Thank you TheLabGuy , I think I'll stick to the zirconia, it gives me more space.

 

[sixonice]

Hey guys I have an upper left cuspid to restore with a full porcelain crown. The dentist asked me which is more durable an e-max ceram layered on Zirconia coping or on an e.max press coping??
Recently I attendend a presentation on e.max by Pia Meuller (CDT),and she said there is no study done comparing these two options. The only study she knows of , compares e.max ceram layered on Zirconia with Monolithic (Full Mass) e.max press, where e.max press exhibits much more durability.
the prep is very discolored so I have to use an opaque core, so it should either be e.max HO ingot or a Zirconia core. I know Zirconia gives me more space for layering, but the dentist wants to know which is more durable.
Can anyone help??

I have a better idea! Press this case FULL CONTOUR out of e.max. Then your getting a full 400 Mpa restoration (the entire crown is all Lithium Disilicate) that will look nice & give your doctor something that can he or she can place with conventional cementation!

 

[TheLabGuy]

six,
He said the prep was really dark.

 

[sixonice]

yep.......duh.......missed it!

 

[Al.]

I would do it in Emax using a HOO or HO1 or 2 what ever the shade requires.
Wax the lingual full contour 3/4 of the way up or even higher. And only layer the facial.

If he needs the extra strength he can bond it to the tooth, which he cant do with zir.

This is the way I do it. But this is a bi and in LT but for cuspids do the lingual full contour in HO and just glaze it as is and stain and layer the facial.

 

[AGV]

Al, this is a good solution and a very good restauration. I will remenber it in next jobs.

 

[ajames]

My personal Opinion

I will recomend myself either a staining block of Lithium Disilicate (e.max) press instead of using a Zr core.
some of the advantages
1. You can not etch Zr
2. You can etch E. Max
the Monolitic E.Max stained is super strong and If you have a shade that is pretty transluicent as C1 o D1 you can match really nice with the HT ingots
with ZR the core always be Opaque and not to easy to mask
regardig durability! I will stay away of pressing over Zirconium, I have had failures with my patients and it is not fun!
when you try to remove a broken Zr crown it is a pain!!!!
in those situations where oclussion is a key a will leave the entire palatal surface and incisal edge in the block, if you want to change the value just do it in the facial, that way you will mantain the crown as strong as possible!
so my opinion go with E.Max..........10 to 1.
A.James

 

[dntek]

wrong posting

 

[paulg100]

Ajames:

NYU's study on layered Zirconia and mono emax showed that Press over zirconia is noticeably weaker with unsupported frames, but with proper frame design, press and layered zirconia are virtually the same.

Did the press over failures youve had have a proper supported frame?

ZR is easy to mask, i have done combination cases in the anterior using emax and zirconia on the same case and you cannot tell the differnce between the two materials.

Mabey your ceramist does not fully understand how to work with zirconia properly.

Additionaly i currently have 3 different strength/translucency zirconias in my lab at the minute. Zirconia is alot more versatile than it used to be when it had limited choice of highly opaque cores.

You can further control the translucency by varying the thickness of the cores so again, they are many options for acheiving optimum esthetics with this material.

 

[labman01]

with ZR the core always be Opaque and not to easy to mask

If the ZR is stained, I agree it could be difficult to mask the opacity of the core.

E-max ceram porcelain for ZR has a zir liner application that you apply on the framework before the porcelain is applied. If done right the zir liner completely masks the opacity of the framework after the crown is complete, even at the margin.

 

[Old Navy Tech]

Zr. vs Emax

So since this thread compares Zirconia and Emax (previously Pentron 3G)

I've got a question for you all.

I was just told by a dentist that he's having problems with Emax bonding... he has a Cerac machine... so I'm not sure he sandblast 1 bar and chemically etches, silinates, primes and bonds... Have any of you all experienced a dentist reporting this?... on a regular basis?

Reason I'm asking, is we are searching for a material... to fill the shoes of our beloved HeraCeram... and we are playing with Emax... we are getting a good look by using GC initial (Zr porcelain) on the substructures ... same CTE... but a very close melting temp...we like it better than Emax ceram.... anyway I diverge from my actual question of bonding/cementing issues.

thanks in advance

 

[sixonice]

So since this thread compares Zirconia and Emax (previously Pentron 3G)

I've got a question for you all.

I was just told by a dentist that he's having problems with Emax bonding... he has a Cerac machine... so I'm not sure he sandblast 1 bar and chemically etches, silinates, primes and bonds... Have any of you all experienced a dentist reporting this?... on a regular basis?

Reason I'm asking, is we are searching for a material... to fill the shoes of our beloved HeraCeram... and we are playing with Emax... we are getting a good look by using GC initial (Zr porcelain) on the substructures ... same CTE... but a very close melting temp...we like it better than Emax ceram.... anyway I diverge from my actual question of bonding/cementing issues.

thanks in advance

if the dentist has crowns falling off or debonding in the mouth after insertion, he is certainly not cementing correctly. remember, e.max (lithium disilicate) can be either placed with conventional cementation or adhesive cementation (bonded). bonding is more complex than conventional, so taking a look at his procedures would be the place to start. you do not want to sandblast the restoration before placing. all that needs to be done is a 20-30 second etch in the lab or office, then rinsed, dried & placed. for a more informational look, take a look at this website: Ivoclar Vivadent | The World Speaks e.max
im a little confused about your changing porcelains. stop me if i am incorrect, but is not heraceram a PFM ceramic? e.max ceram is for metal-free lithium disilicate as well as all zirconia.

 

[Gdentallab]

none of my dentists has reported a problem about cementing, knowing that most are using bonding materials instead of cementation.
I agree, GC initial zr works fine over emax, even better.
The color matching is better.
The reason i'm using emax ceram is that i have a stock to finish, otherwise i'll witch to GC.

 

[Gdentallab]

none of my dentists has reported a problem about cementing, knowing that most are using bonding materials instead of cementation.
I agree, GC initial zr works fine over emax, even better.
The color matching is better.
The reason i'm using emax ceram is that i have a stock to finish, otherwise i'll switch to GC.

 

[Old Navy Tech]

Thanks SixonIce and Gdentallab,

HeraCeram is a pfm ceramic, they also have a pressing system (had) :-( that uses the powder in ingot form to press, when you press a shell and layer, you can't see where the pressing stops and the layering begins... BEAUTIFUL stuff... no graying up after bonding like OPC and some Empress.

I agree that his bonding or cementing process is probably flawed, he has a Cerec machine that mills the LD, so I don't know if he unadvisedly sandblasted or did not etch and silinate, prime and bond, or the Lab he used for a while while me and the wife took a small hiatus for baby birthing, didn't etch.

So we've done a couple anteriors in emax with the GC initial and they look great, thought we've found a replacement for our pressing HeraCeram and layering. Now we've had a couple full crown emax's where we waxed and pressed a .3mm shell and layered, CRACKed over night. I've even bought the Bredent wheels everybody talked about using, (Very nice wheels, love them). So maybe there is something other than a CTE that is a deciding factor of layering porcelain?

Also I'm in the process of hooking an account, The Hygienist has 4 Emax veneers that the lateral lost a chunk of layering porcelain 2 days after bonding, (just like 3G use to do) and 3 weeks after bonding they've started turning gray. The Dentist assures me she used the new non amine formula for bonding, (which supposedly was in the catylist causing veneers to go grey) Any thought?... maybe the HT ingot was too translucent?... but why would they look ok on tryin and gray up later.??? I plan on using my remaining HeraCeram to style her up just right.

 

[TheLabGuy]

Ferric Sulfate

 

[rkm rdt]

I never had any delamination problems with OPC 3G,in fact the veneering porcelain is compatible with zirconia.

I think your problem is with not removing the reaction layer properly.This will cause fracture or delamination of the veneering porcelain in either OPC 3G or Emax.

". Now we've had a couple full crown emax's where we waxed and pressed a .3mm shell and layered, CRACKed over night."

.3mm is too thin, .5mm is the recommended minimum thickness.

 

[Old Navy Tech]

Got the full skinny from the doc... He has a Cerac machine, He mills LD... OIL from the milling machine, hinders the acid from etching the LD... He is told by the company to steam out the oil, maybe soapy water scrub... then etch.
He has not had veneers or crowns come away from the tooth structure that were fabricated in the lab (pressed)

any ideas on the graying?