Removing PFM crown from Ti Abutment

[Nimble]

Hello everyone,
I’d like to know how to remove PFM crown from Ti abutment to rebake porcelain. Cement is Kerr NX3. This is a screw-mentable.
I’ve looked in forum but all I saw was about removing ceramic crown...It maybe same ? but would like to know
detail ( temperature, time, vacuum?).
Also I am wondering is there any way to remove cement without sandblasting? I’m worried of changing occlusion because crown is metal occlusal. (I’ve experienced reduced occlusion by blasting too many times before cement! )
I’d appropriate any advice regarding restocking porcelain after de- cement framework! Doing this for first time and cannot afford mistake.
Thank you very much !

 

[Contraluz]

This is what I do:

High temp 390C
Start temp 250C
Slow rise 25C/min
Holding time about 10 min

I use the same protocol for Zr or e.max crowns

However, if the PFM crown has been in the pt for a while, I sandblast the porcelain surface before putting it into the furnace. If the crown is real old, before the above mentioned, I'd put it into the furnace to dry, by 150C, or so.

 

[Nimble]

Thank you so much for your answer.
How about vacuum? Off?

 

[doug]

no vacuum

 

[Contraluz]

Thank you so much for your answer.
How about vacuum? Off?

As Doug mentioned, no vacuum.

I'd like to add, if you deal with an older PFM crown, after de-cementing it, sandblast the surface again and run a glaze cycle with it. This will burn off any remaining organic material (bacteria) that might have formed in cracks, or so. I am always surprised, when I get a PFM bridge to add, polish or convert an abutment crown into a pontic, that has been cemented for a while, how many cracks there are.

 

[Nimble]

Thank you very much!!
Really appreciated your help.

 

[millennium]

Before doing anything to the pfm/ti abutment throw them into this over night. The porcelain wash will dissolve any bio crap that has gotten into the porcelain over time. It will not damage alloy or TI. You will se lots of bubbles after immersing the crown/Ti abutment.

 

[Nimble]

Thank you for more and important tips. This crown is very recently delivered. Pt is not just happy with contour. My concern is that since I burnished metal margin to ti abutment after bonding, I hope it will not be problem for separating.

As Doug mentioned, no vacuum.

I'd like to add, if you deal with an older PFM crown, after de-cementing it, sandblast the surface again and run a glaze cycle with it. This will burn off any remaining organic material (bacteria) that might have formed in cracks, or so. I am always surprised, when I get a PFM bridge to add, polish or convert an abutment crown into a pontic, that has been cemented for a while, how many cracks there are.

As Doug mentioned, no vacuum.

I'd like to add, if you deal with an older PFM crown, after de-cementing it, sandblast the surface again and run a glaze cycle with it. This will burn off any remaining organic material (bacteria) that might have formed in cracks, or so. I am always surprised, when I get a PFM bridge to add, polish or convert an abutment crown into a pontic, that has been cemented for a while, how many cracks there are.

no vacuum

　Thank you very much!

 

[Nimble]

Thank you ALL for important tips. This crown is very recently delivered. Pt is not just happy with contour. My concern is that since I burnished metal margin to ti abutment after bonding, I hope it will not be problem for separating.
Also, is sandblasting necessary for removing cement or it will come off with knife after burned? i just don't want to blast too much.

 

[millennium]

After the furnace cools down to room temp the crown should come off the abutment pretty easily. Then sandblast the inside of the crown and the abutment area where the cement is going to be

 

[Nimble]

Thank you so much.
I learned a lot today!
Thank you all of you, kindly sharing your knowledge from your experiences.
Thank you “Dental-lab network”!

 

[JMN]

Thank you so much.
I learned a lot today!
Thank you all of you, kindly sharing your knowledge from your experiences.
Thank you “Dental-lab network”!

Stick around, "we've only just begun."

 

[Contraluz]

My concern is that since I burnished metal margin to ti abutment after bonding, I hope it will not be problem for separating.

So, if the fit is rather tight, I screw the crown onto an analog and hold the analog with a hemostat or small pliers. I then tab the hemostat with an instrument, downwards (apical, so to speak). Sometimes it needs a 'firm' tab...

 

[Nimble]

That’s brilliant!
Thank you very much.

 

[myko_rdt]

Sorry to bring this up from the dead, but what cement are you guys using for specifically PFM to ti-base? Thank you!

 

[Contraluz]

Sorry to bring this up from the dead, but what cement are you guys using for specifically PFM to ti-base? Thank you!

Multilink Hybrid Abutment Cement from Ivoclar

There are others of same quality, I am sure they will chime in soon.