How do I separate a crown from implant?

[the_prez3]

Weird situation. We have a zirconia abutment with a crown cemented to it come out of the mouth after two years. Nothing is broke and nothing debonded. Apparently the screw somehow backed out. We’d like to separate the crown from the abutment and salvage everything. I’m considering firing the entire assembly in the furnace to comprise the glue bonding. Of course I know the ti-base would need to be rebonded. Anyone have any suggestions? Is there a chemical that would dissolve the cement instead? Any help would be appreciated.

 

[zero_zero]

460C for 10 minutes, slow cool...there's no chemical solvent I'm aware of.

 

[KTR]

Agree with zero!

 

[larsondental]

Me Too ! 800F for the metricly challanged

 

[the_prez3]

Thanks guys. I’ll give it a shot

 

[Contraluz]

Thanks guys. I’ll give it a shot

Do a very slow fire cycle and start with low temp. Also slow cooling. I have had crowns cracking on me. 400 degrees celsius should do the trick.

 

[Contraluz]

Do a very slow fire cycle and start with low temp. Also slow cooling. I have had crowns cracking on me. 400 degrees celsius should do the trick.

I would like to add, the ones cracking were the high translucent (low mpa) Zir crowns...

 

[the_prez3]

Thanks so much guys. Worked like a charm. Everything came apart really well! You guys are awesome!

 

[doug]

 

[adl]

It’s going to happen again if occlusion is not fixed

 

[Car 54]

It’s going to happen again if occlusion is not fixed

Agree, if you still have both casts, confirm any interference's and clear them before sending it back.

Also, even though we're using titanium screws, some Drs like to torque it to the recommenced setting,
wait 5 minutes and re-torque it, in case there was any slight screw "rebound".

 

[the_prez3]

Good tips on this. So if there is contact with opposing, it can cause an implant screw to back out? Is this common? Is there anything they put inside the screw channel to prevent the screw from backing out?


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[Car 54]

Good tips on this. So if there is contact with opposing, it can cause an implant screw to back out? Is this common? Is there anything they put inside the screw channel to prevent the screw from backing out?


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If it's a posterior that has interference's when you go into excursions, then yes, it can over time
cause screw loosening due to hitting on areas of the crown it's not meant to, fulcruming it.

Also, from my understanding, there should only be light occlusal contact in "clenched" occlusion.
In normal occlusion, they should just be out of occlusion, being able to pull light gauge
shim stock through the occlusion.

 

[zero_zero]

Is there anything they put inside the screw channel to prevent the screw from backing out?

This should work...if you could get around FDA somehow

 

[J Pierce]

Great info!!

 

[the_prez3]

LOL @ zero


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[the_prez3]

It’s a #9. A little confused as to how a screw could back out that far. Doctor filled the screw channel with some sort of puddy before cementing the crown. The implant was in the mouth for two years and patient walked into the office with the complete assembly in her hand. The screw looked fine, no stripped threads. It was difficult to rotate the screw by hand as it was so I don’t really know how it was able to back out with no rotation of the abutment possible. It’s a nobel replace 4.3mm I checked the ti-base fit in an implant replica to see if it would wiggle but the fit was good.


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[KentPWalton]

I wouldn't suggest you firing the metal. You should grind it off. If you put the Ti base in the furnace, you immediately void the manufacturer's warranty. If you put it in the furnace, you do not get credit if you return it. You will compromise the integrity of the metal and cause issues down the road. My opinion is to order a new ti base and charge the Dr. for it.

 

[Car 54]

LOL @ zero


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It may sound funny, but some Drs have tried it.

It’s a #9. A little confused as to how a screw could back out that far. Doctor filled the screw channel with some sort of puddy before cementing the crown. The implant was in the mouth for two years and patient walked into the office with the complete assembly in her hand. The screw looked fine, no stripped threads. It was difficult to rotate the screw by hand as it was so I don’t really know how it was able to back out with no rotation of the abutment possible. It’s a nobel replace 4.3mm I checked the ti-base fit in an implant replica to see if it would wiggle but the fit was good.

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That is pretty bizarre

 

[Car 54]

I wouldn't suggest you firing the metal. You should grind it off. If you put the Ti base in the furnace, you immediately void the manufacturer's warranty. If you put it in the furnace, you do not get credit if you return it. You will compromise the integrity of the metal and cause issues down the road. My opinion is to order a new ti base and charge the Dr. for it.

As always, thanks for the great work, Kent