Fun with Stock Abutments

[Brett Hansen CDT]

This case is from a doctor who has me design crowns with food traps to make up for the poor implant placement/abutment choice. He insists on his crowns having the same buccal countours of the adjacent teeth, even if this means that I ridge lap the crown material on top of the tissue. I have talked with him before about allowing me to provide his abutments so that we can do a better job with the emergence profile of his crowns so that the crown design is not compromised by an inadequate abutment. Within the last month he agreed with me on this point and said he was going to start taking fixture level impressions. Here is a case he sent back for me to remake. I plan on writing him a letter to give him my thoughts about how this crown design will cause his patient problems. Please give me your thoughts so I can try to reinforce the idea that he needs to stop using these stock abutments. This doctor only sends us his implant work(3-4 crowns a month) and has to talk on the phone about every case for fifteen minutes. Basically, he is kind of a pain and I won't be too upset if he stops using us. The first pic is of the crown that he sent back because the abutment was showing. The abutment was showing because the margin of the abutment was supragingival.

 

[CatamountRob]

What is the abutment? Straumann solid or Snappy or something like that? I'm not sure it matters what abutment is on it, it's a tissue level implant and it isn't deep enough, or am I missreading the pics?

 

[Brett Hansen CDT]

It is Straumann. You are right Rob, on this case it wouldn't make a bit of difference on the buccal; however, the lingual, mesial, and distal were not supragingival so the abutment could have been widened to create a better emergence profile and decrease the food traps. Normally on his cases, the abutment isn't supragingival and the implant is placed more in the center of the ridge. Instead of extending the crown past the margin of the abutment, I have to extend the crown buccally from the margin and then down over the buccal ridge to make the cervical of the crown blend with the adjacent teeth. On those cases, a custom abutment would be a much better choice for his patient's and how he wants his crowns designed.

 

[JohnWilson]

Did you wax it straight to the analog or did you use a plastic burn out cap?

Last week I did a FCZ and when we scan it we had to all but eliminate ALL cement parameters to keep the restorations from rotating in the mouth. Straumann prespaces the analogs which makes things tricky in cad. I had to mill the same crown 3 times till I had the right fit.

 

[JohnWilson]

It is Straumann. You are right Rob, on this case it wouldn't make a bit of difference on the buccal; however, the lingual, mesial, and distal were not supragingival so the abutment could have been widened to create a better emergence profile and decrease the food traps. Normally on his cases, the abutment isn't supragingival and the implant is placed more in the center of the ridge. Instead of extending the crown past the margin of the abutment, I have to extend the crown buccally from the margin and then down over the buccal ridge to make the cervical of the crown blend with the adjacent teeth. On those cases, a custom abutment would be a much better choice for his patient's and how he wants his crowns designed.

It would not have mattered to do a custom abutment on this case, the metal you are seeing is actually the outside edge of the implant, I have sen some clients actually prep the outside of the fixture to allow the crown margin to blend more with the tissue rather than fixture lap with the restoration.

3rd party tissue level straumann custom abutments actually make it worse as the abutment goes to the outside of the fixture not just internally like the synocta abutments.

 

[Brett Hansen CDT]

We don't use the plastic burnout caps on e.Max because of that lip on the caps. I have tried to carefully remove it before pressing, but I get better margins if I just use a separate analog and wax it without the cap.

Am I right to say that the design of this crown has a high likely-hood of causing the patient problems down the road?

 

[CatamountRob]

Yes. It's a nasty trap. I've had the same type of issues with the same type of implants. I'd have done it the same way you did the first crown.

 

[PCDL]

From my end, just keep your client alerted to the poor surgical placement, and make your crown to fit the solid abutment well, with a good, sealed margin. There is only so much you can do to compensate for bad surgery. I cringe at the cases where the GP preps the bevel on those tissue level implants.

If you have a good relationship with your GP, recommend a surgeon that you like. Both the GP and new surgeon will be happy with you, and your life will get easier.

 

[JSnyder85]

John, so are you setting your die spacer parameters to 0 for 3shape, with the single stage analogs?

Did you wax it straight to the analog or did you use a plastic burn out cap?

Last week I did a FCZ and when we scan it we had to all but eliminate ALL cement parameters to keep the restorations from rotating in the mouth. Straumann prespaces the analogs which makes things tricky in cad. I had to mill the same crown 3 times till I had the right fit.

 

[JohnWilson]

Almost, depends on which system I am using, still messing with settings I think I have the old straumann solid abutments dialed in perfect.

 

[CoolHandLuke]

so basically, this doctor is a very fickle fellow who is more concerned about micromanaging you instead of his own practice...

That Was A Close One, Ladies And Gentlemen Sound Clip and Quote - Hark

 

[JSnyder85]

Im using .010/.020 but still having some rotating. It seems to be the Straumann solid abutments/ITI which im having the most issues with. It seems like i have a somewhat better fit with the nobel snappy and other systems. I used the wax-up sleeves for anything done hand-wax although just recently started using them. I had better results in years prior just conventionally waxing to the analog, but as of late the wax up copings seem to be providing a better fit(excluding Astra). I will try dialing down the spacer parameters.