This is not normal !!!

[cosmicsport]

One of our Drs send me these pictures with the question what might have happen is this case.
The pictures were taken 2 years apart from each other. I know the stump was dark before but we covered the show-through as good as we could.

I have an idea but what do you guys think ?? Any thoughts ??

Thanks Guys.

Before:



After:

 

[paulg100]

what has he used for bonding, maybe this material has disscoloured over time?

 

[cosmicsport]

Ivoclar Vivadent bonding/luting cements

 

[Toast]

Looks like the bonding agent is yellowing. My Ivoclar rep is pushing the Variolink Veneer a lot lately since its amine free and will not yellow.