Intaglio surface of E.max

[TheLabGuy]

What are you doing to the intaglio (underneath) of E.max before you send it out to the Dentist for seating?
Etching?..... what percentage?
Sandblasting?.....how much pressure?
Nothing?
Are you telling your clients to salinate after trying in?
Telling them they must bond versus the option to cement?
Seeing any debondings?

 

[rkm rdt]

low pressure sandblasting around 20 psi
hydrofloric acid 20-30 seconds( etch-it)

I never salinate.(silane) I think the silane coupler is the critical link to a proper bond.I prefer the Dr take control of that step.

I recommend bonding whenever possible ,so far so good wrt emax.

 

[JohnWilson]

What are you doing to the intaglio (underneath) of E.max before you send it out to the Dentist for seating?
Etching?..... what percentage?
Sandblasting?.....how much pressure?
Nothing?
Are you telling your clients to salinate after trying in?
Telling them they must bond versus the option to cement?
Seeing any debondings?

Alox LOW pressure then we use Ivoclars red etch for the recommended time which I believe is less than 30 seconds.

We do recommend bonding the restorations and we never silane at the lab. For clients that are not very familiar with adhesive dentistry we recommend they acquire/use the newer single use silane packages. I have seen too many time a beautiful restoration just fail because the client is unfamiliar with the proper protocol with bonding.

 

[doug]

I blast with Alox2, that's it. I used to etch but since the docs don't clean the crowns properly after using the try-in paste the etching is wasted. I put the burden on them to make sure they etch and silanate prior to bonding, after they do the try-in.

 

[PGguy]

low pressure sandblasting around 20 psi
hydrofloric acid 20-30 seconds( etch-it)

I never salinate.(silane) I think the silane coupler is the critical link to a proper bond.I prefer the Dr take control of that step.

I recommend bonding whenever possible ,so far so good wrt emax.

Second that

 

[TheLabGuy]

You know Doug brings up a great point and something I was mulling over when thinking about this......Yes, even Marines think about other things from time to time than something getting blown up. What about all the self-etching bonding agents out there. Most of my clients use a self-etching type of bond (NX3, APEX, etc...) What's the purpose of etching when the bond has the self-etching in it? Just a thought, okay back to blowing things up!!!!

 

[PGguy]

If I remember correctly the 1st step is to silinate before trying in so you do not contaminate the restoration and half to re-etch. Also I believe the self-etch is phosphoric acid and our etch is hydrofluoric acid

 

[TheLabGuy]

Okay, that brings up a point about etching. Labs primarily use HF (Hydroflouric) while Dentists primarily use phosphoric, in which to my knowledge is nothing compared to the etching properties of HF.

 

[JayDO]

Guys
Please let me clear a few things up.

1. Blasting of lithium disilicate prior to seating is a huge no no. This is stated numerous times throughout the instructions for use. It has the potential to weaken the material.

2. Etching of the internal surfaces should be done with 5% HF etch for no more than 20 seconds. Etching for longer can inhibit bond strengths. Most labs do this when the restoration leaves their building because few doctors do it. It is important to find out if the doctor is doing HF etching chairside because over etching is possible with lithium disilicate.

3. Silane should always be applied chairside as it will lose effectiveness when left exposed to air for extended periods of time. It should also be applied after try in as the residue from try in paste will make it ineffective. The try-in can be cleaned out using water and then the restoration should be thoroughly dried before the silane is applied.

4. Phosphoric etch is used chairside to condition the prepared tooth and open the dentin tubules so that the primer can infiltrate them and create a micro mechanical bond between the cement and the dentin. The silane creates the bond between the tooth and the cement.

I hope this helps.

 

[sixonice]

Guys
Please let me clear a few things up.

1. Blasting of lithium disilicate prior to seating is a huge no no. This is stated numerous times throughout the instructions for use. It has the potential to weaken the material.

2. Etching of the internal surfaces should be done with 5% HF etch for no more than 20 seconds. Etching for longer can inhibit bond strengths. Most labs do this when the restoration leaves their building because few doctors do it. It is important to find out if the doctor is doing HF etching chairside because over etching is possible with lithium disilicate.

3. Silane should always be applied chairside as it will lose effectiveness when left exposed to air for extended periods of time. It should also be applied after try in as the residue from try in paste will make it ineffective. The try-in can be cleaned out using water and then the restoration should be thoroughly dried before the silane is applied.

4. Phosphoric etch is used chairside to condition the prepared tooth and open the dentin tubules so that the primer can infiltrate them and create a micro mechanical bond between the cement and the dentin. The silane creates the bond between the tooth and the cement.

I hope this helps.

Everything you said is 100% on point and correct. You are certainly well versed. Every point made is on the "Bulls eye".

 

[Matrix]

Guys
Please let me clear a few things up.

1. Blasting of lithium disilicate prior to seating is a huge no no. This is stated numerous times throughout the instructions for use. It has the potential to weaken the material.

Here is what I do not understand. In the e.max instructions for use on page 34, Ivoclar clearly states to use aluminum oxide to remove the reaction layer on the crown inside and out. How does the inside of the e.max crown change after processing before etching where you do not want to blast the inside surfaces prior to etching? I always clean up the internal surface prior to etching with Alox to remove the remnants of the Peg It material and any black marks from the hemostats.

 

[JayDO]

Here is what I do not understand. In the e.max instructions for use on page 34, Ivoclar clearly states to use aluminum oxide to remove the reaction layer on the crown inside and out. How does the inside of the e.max crown change after processing before etching where you do not want to blast the inside surfaces prior to etching? I always clean up the internal surface prior to etching with Alox to remove the remnants of the Peg It material and any black marks from the hemostats.

You are absolutely correct. But what you have to remember is that you will, at minimum, be firing glaze on the restoration after divesting. This firing will repair any potential damage caused by blasting. However, if you blast before seating, you do not have the chance to do a firing and firing the material again would negate the point of blasting. So, before the crown goes out the door, it should not be blasted.

 

[doug]

You are absolutely correct. But what you have to remember is that you will, at minimum, be firing glaze on the restoration after divesting. This firing will repair any potential damage caused by blasting. However, if you blast before seating, you do not have the chance to do a firing and firing the material again would negate the point of blasting. So, before the crown goes out the door, it should not be blasted.

Can you provide the documentation for this. I've been doing pressables for 15 years and this hasn't been an issue that has ever been brought to my attention. Seems I'm not alone here.

Later the same evening...

Jaydo, My Apology to you. I started wondering(second guessing myself) and went to the Ivoclar site, downloaded the manual and re-read all of it. It does say to use only the "polishing" beads, which I have and use.

I do lightly blast the intaglio with Al02 prior to sending the crown out. I have never had a problem with that so I'll probably continue to do it. Dam those GMP's

 

[rkm rdt]

I'm with Doug on this one. In fact I have not seen any problems under 10x magnification.
If there was any damage then I doubt that glaze would fix it.

 

[Matrix]

I'm with Doug on this one. In fact I have not seen any problems under 10x magnification.
If there was any damage then I doubt that glaze would fix it.

I agreee with both of you. The glaze firing temp is no where high enough to heal any damage to the surface of the internal surface of the e.max crown. Plus I do not think a light blasting of the internal surface prior to etching is hurting anything. The etching is changing the surface texture and creating microscopic undercuts more than blasting is.

 

[JayDO]

I am curious as to why everyone seems to want to contradict a recommendation from the manufacturer of the product when it has potential to harm the material.

 

[TheLabGuy]

I'm curious why Ivoclar's reps would be teaching to sandblast 20-30 p.s.i. with AlO2 and etch (HF) less than one minute before sending out, did they change their protocol recently?

 

[rkm rdt]

I I don't tink it's the Ivoclar reps to the best of my knowledge.

I was on a clinical research course recently where the so called " technician guru" recommended not to sandblast prior to delivery.

When I questioned his protocol he admited he was not familiar with Emax and was referring to Empress.

He also said to silane before delivery which I disagreed with as well.

For what it's worth ,he reeked of monomer. ainkiller:

 

[user name]

I am curious as to why everyone seems to want to contradict a recommendation from the manufacturer of the product when it has potential to harm the material.

Because we work with it every day, and we are interested in producing the best results possible, not just covering our asses as a manufacturer not knowing what level of numbnuts are going to be using the product and cant do alittle thinking for themselves. Ivoclar has to assume the product is going to be used not only by top shelf artist/scientists, but also the few who dont know enough to remove the silicon ring before burn out.

 

[TheLabGuy]

I I don't tink it's the Ivoclar reps to the best of my knowledge.

I was on a clinical research course recently where the so called " technician guru" recommended not to sandblast prior to delivery.

Sorry, I should of been more clear, these "reps" were also from the technical side of the house not the sales weasels, I sent out an email this morning to my sales weasel to find out what he's telling folks the current protocol and waiting for a reply, which I'll post.