Zirconia detaching from Ti base

[Badgerdental]

Hi there, I do a fair amount of Zirconia abutments cemented to Titanium bases. I've had one (now former) client who has had a few that I've done for him where the Zirconia has debonded from the Ti base. Out of the hundreds I've done this has only happened with this one client. Have a guess whether this is frustrating the hell out of me. I've looked back at my records and there has always been other Zirc to Ti base jobs done for other clients at the same time as these problem ones and they are all still there causing no problems. I always check use by dates and use the correct materials i.e multilink, monobond etc.I know there's a whole raft of techniques and materials with which you can enhance the bond between the Ti base and the Zirconia but considering this has happened with only one Dentist, has anyone had an experince like this, and can anyone suggest a reason for this?
Also, I have one to fix now. It has an emax crown cemented to the Zirconia abutment. Can anyone suggest a way of removing the emax crown from the Zirconia? I've tried putting in the furnace to 400C to break down the cement in the past but the emax cracks.

 

[capickettcdt]

One Doctor...It's the Doctor.
Don't waste time trying to save the unit. Just do it again and then suggest that you are too busy for He/She.

 

[H.Ross]

The emax will crack of course. Cement will heat and expand causing force or stress on the emax structure. I usually sandblast my Ti base and use RelyX from 3M ESPE

 

[Badgerdental]

managed to get the crown off without cracking! Slowed the heat rate right down, up to 450C. Anyway, worked in this case. Another product I've been advised of to aid the bond between the Ti base and the Zirc is Futurabond by Voco, anyone had a go at this?

 

[Sevan P]

Do you etch the emax crown before cementing? I have never had either ZR abutment or screw retained ZR or Emax de-bond since i moved to multilink implant. It is some god stuff.

 

[PCdental]

I have had the same problem recently... one doctor. Badger, did you ever figure anything out?

 

[DESS-USA]

The other issue is the possible design of the ti base chimney. Like a prep tooth you have greater retention with parallel walls. The slightest taper will dramatically reduce your bond strength. Most ti bases have tapered walls and regardless of their height they have a significantly weaker bond adhesion than using a parallel walled ti base. Here is an example of a test we did comparing a 4.5 tall chimney with a 5 degree versus a 3mm tall chimney with 0 degree...