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Dr. Hall, I have just had two all porcelain crowns made for my two front teeth, #s 8 & 9. The crowns were a wonderful color match to adjacent teeth and I unreservedly authorized them to be cemented in. After the cementing procedure, I looked in the mirror and IMMEDIATELY noticed a slight grayish hue to the teeth. I inquired about this, and the dentist stated that the cementing product he used was transparent in color. I have looked at the teeth in different light conditions over the past several days and STILL see this. Is there something in the cement or its curing that could have caused this? Sara, That is one possibility that could account for a difference in perceived color between the crowns when they were tried in and when they were cemented. If the crowns are dry, they don’t transmit the underlying color of the tooth as well as they would with a bonding medium between the tooth and the crown. Darkness, stain, or metal posts in the teeth underneath could cause a gray tinge to the crowns. What I did in my practice when my bonding cement was going to be transparent was use a clear glycerin to accurately mimic what the resulting color would look like when it was bonded. If that’s not the case, then the only other explanation I can think of for a discrepancy in the color like this would be color metamerism, which is the property certain materials have to appear one color under one light and another color under another. Some porcelains may match the teeth under a cool fluorescent light but then won’t match in, say, daylight or under incandescent light. But a clear bonding cement made by a reputable manufacturer will not change colors upon curing and won’t impact the color of the final result beyond helping transmit the underlying color. If the grayness is only very slight, maybe it isn’t really noticeable, and since both very front teeth are the same, it shouldn’t be distracting. However, if the grayness is significant and noticeable to others, I think your dentist should fix this. At his expense. It could be a great learning experience for him. Dr. Hall Do you have a comment to add? I’d love to hear from you! Please enter your comment below. Click here to ask Dr. Hall a question of your own. |
About David A. Hall
Dr. David A. Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does advanced internet marketing for dentists.
Dear Dr. Hall,
Thank you so much for your thorough and thoughtful response.
In my case, the crowns were tried on “dry”. As such, the potential reflective factor from the underlying teeth was not taken into consideration prior to the cementing process. Once they were cemented, it was too late.
Assuming the lab does a good job matching the color of the crowns to adjacent teeth, what techniques are used to minimize or correct for this “bleed through” effect caused by underlying teeth?
In my case, the grayness is fairly noticeable. This effect becomes more pronounced closer to the gingival edge of the crowns. I have a big, wide smile and work in a professional, highly visible capacity. My dentist has agreed to refund a portion of the cost of this work and I will be seeking to have these crowns redone elsewhere. I wish I had found your site earlier…
Response by Dr. Hall:
Sara,
It’s not just a simple matter of “matching” the color, as you’ve discovered, because it’s more than just a straight “color” – it’s translucency also, and the texture of the crown can affect the perceived color, too. That’s why that try-in is so important.
Had this been me doing the try-in, I would have tried on the crowns with clear glycerin and noticed the color bleed-through. Seeing what I saw, I would first have tried to use an opaque bonding cement, and I would have had a corresponding opaque try-in gel. If that failed to produce a satisfactory result, I would have taken a photo of the case as it was tried in and relayed that back to the lab with a request that the crowns be re-made to mask out that underlying color.
However, this should really have been addressed much earlier in the process. At a minimum, the dentist should have been more explicit with the laboratory technician about the underlying dark color of the teeth. Better, if this were me or another highly trained cosmetic dentist, we would have noted that dark color of the teeth to start with and would have addressed that at the crown preparation step. When you have to use opaquers in a front tooth, the deeper you place those, the more room you have to create a natural translucency in the tooth. So we would have opaqued that color out during the crown preparation step, using an opaque buildup material close to the final shade of the teeth. It’s always a little unpredictable when you try to achieve that opaqueing with just the crown.