Advice on Emax crown over Zirconia abutments

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wileyE

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Hello all. I am new to the forum and appreciate all the good information. I was hoping someone could offer some guidance to a patient (yours truly) working with a dental lab and a prosthodontist.

I recently had custom Zirconia abutments and ISP e.max crowns placed on titanium implants on my #7 and #10. The esthetic result looks fine under direct lighting, but I am noticing a grayish effect on both teeth when I view them under lower indirect lighting. The grayish effect is about a half-shade (#7) to quarter-shade (#10) darker than the surrounding teeth under this type of lighting.

Now since the abutments are of Zirconia and white in color, not titanium, I assumed the custom shade would be a near perfect match. I am hoping to get a better result, if possible. I am not sure what might be causing this grayish effect other than the implant color showing through the abutment and crown, or maybe it's just a color issue in general. I read that one recommended approach was using an MO e.max ingot to mask any shadowing with some additional layering using IPS e.max Ceram. Is shadowing really an issue with a Zirconia abutment?

Thanks for any advice. :)
 
rkm rdt

rkm rdt

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The shadowing is usually caused by a metal substructure showing through the translucent crown.
Are you sure the abutments are zirconia and not titanium?
 
Brett Hansen CDT

Brett Hansen CDT

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The High Translucency e.Max ingots have had problems "graying out." For all anterior full crown cases, we use either the Low Translucency ingots and then layer the facial with veneering porcelain so that the crown doesn't look dead. The other option is to use the Impulse ingots that Ivoclar has put out to solve the value problem you are describing with the HT ingots.
 
Alistar

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I have done a dozen or so E.max over zirconia abutments. The results are excellent in all lighting conditions if the abutment is designed correctly and the right ingot and layering is used.

Did you get your shade taken directly by the lab? Did you consult with the lab/ceramist before the seating? Did you comunicate clearly with your Dr about what your standards were? A lot of times there is a communication breakdown between the doc, patient, lab/ceramist.
 
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wileyE

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Thanks all for the replies.

rkm_rdt, I can confirm that the abutment is Zirconia, since the prosthodontist specifically ordered them in place of my much older titanium abutments in order to slenderize the diameter of the abutments and to achieve a better esthetic result.

Brett, I was impressed by the look of the bare abutments in comparison to the older titanium ones, since they had a lighter color and a slender profile. In your opinion, are there other attributes in the construction of the Zirconia abutments that are critical in achieving an overall superior esthetic result? The prosthodonist speculated that the abutments might be acting as a conduit, much like a fiber optic cable, and transmitting the color from the titanium implant to the crown. If so, can this effect be reduced or eliminated with a particular design?

Alistar, I did visit the lab for a custom shade appointment where they took photos, digital color readings, and made colored pencil sketches, which lasted approximately 30 minutes. I went in again on a second appointment where the final color and shape evaluation were made, which lasted approximately 90 minutes.

One important point, I believe, was the lab did not have the ability to test the e.Max crowns on the mounted Zirconia abutments, since the prosthodontist did not have temporaries made. That is, I arrived at the second appointment with my cemented-in old crowns and abutments. I wonder if this makes the process much more difficult for the dental lab in achieving a good end result?

I'll admit my naivete kept me from taking a more active role in the initial communication between the prosthodontist and the dental lab/ceramist beyond my request to the doctor for a non-titanium solution. Given my understanding of the situation now, it seems there might be trade-offs between shade and translucency. A natural appearance in typical life situations is my primary desire and translucency is a more of a nice-to-have.

P.S. I meet with the dental lab tomorrow, after visiting my prosthodontist yesterday. Hopefully, there will be a consensus on how to proceed. Thanks again for all your good advice.
 
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sixonice

sixonice

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do you know exactly which e.max ingot was used for the case? with the abutments being zirconia (i am assuming plenty of bright whiteness!) you could have used pretty much any e.max ingot and had good success in matching shades. what was the shade of the final retorations? in your case I would have used the LT ingot, probably 1 shade lighter than what the doctor prescribed (just to give me the ability to shade down in need-be) and then complete the case. i probably would want a slight incisal cutback and small layering as well.
 
Brett Hansen CDT

Brett Hansen CDT

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@wiley, The abutment won't transmit the grey color of the implant in the way you described at all. Zirconia is a very opaque material. We use it to block out dark stump shades and we use it on titanium abutments when we want to make sure that the final shade and esthetics of the crown are not adversely affected. I am almost certain that your shade problem is due to the type of ingot that was used to fabricate your crown as Sixonice states above.
 
Alistar

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Sounds like you're working with a good lab. Sometimes things just don't turn out "perfect". But like Sixonice said...maybe they picked the wrong ingot, or since you're saying they look too "grey", they could have used too much translucent porceline. I've been there.

Anyway, we could speculate all day long. Hope things get resolved.
 
user name

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Since you said the shade taking took so long, my guess is your teeth got dried and that causes them to lighten quite a bit. It shouldnt take more than 3-5 minutes to take a shade. Could also be what it was cemented/bonded with.
 
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hickory94

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We have opaqued our abutments, if they were custom with a Semi-precious or noble metal or titanium as long as you have titanium porc.
 
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wileyE

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Hello all. I just wanted to post a follow-up to this thread regarding the ceramic crowns for my implants that were "graying out" when seated. I visited both the doctor and the lab, and the consensus was that both of my crowns should be redone. I did provide the lab with an excerpt of this thread to give them the perspective of multiple opinions.

I am happy to report the new crowns look and feel great, and completely surpass the decade-old ones they were originally intended to replace. The "graying out" effect, as I understand, was addressed by choosing a less translucent ignot as a base. I also noticed too that that shape of the crowns came out a tad better than the first try, and needed much less adjustments by the doctor to seat properly.

I would like to thank everyone for their advice, and truly feel the extra persistence by all parties involved did yield a perceptibly superior end result that makes a difference in my overall quality of life. This was well worth the additional time, effort, and yes, a little bit of physical pain on my part since the first try had to be drilled out, after a couple of shots of Novocaine, of course. But I am a happy camper! :)

Thanks again,

--Wiley
 
Brett Hansen CDT

Brett Hansen CDT

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I am glad you found the information you needed to get desired esthetics from your crowns.

Brett
 
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