I snapped this picture while I was visiting The Winter Lab the other day. These are two preparations for pressed ceramic veneers. I like looking at pictures of preps because they tell me so much more than I can see by just looking at the models.
I use a split flash similar to the image here so that I can get better depth in the image. The shadows and contrast make the nuances of the preparation more visible, although sometimes I feel better about myself if I can’t see all the detail!
Looking at images like this make my work better, and getting better saves me time, money, and stomach lining.
If we look at the preps above, there are very clean margins and a well made impression. There is plenty of room for the ceramist to work and create depth and beauty in the porcelain.
There are some things that could be changed to make them even better.
Notice the diamond bur marks on the preps. By simply polishing the prep with a white stone followed by a brownie point those marks would be gone. Taking them away leaves the ceramist with smooth surface that will reflect light more naturally. It also makes seating a bonded restoration more predictable and allows greater marginal integrity.
Also notice the labioincisal angles. While the incisal one-third of the preps have been laid back nicely, those angles are very sharp and will create stress points in the final restorations. The white stone is perfect for rounding those angles.
Finally, look at the palatal extent of the preps and observe how they flare into very thin enamel margins. Not only will those margins be difficult to finish, they make creating emergence profile challenging. When breaking the contacts on a veneer prep or closing a diastema a more predictable method is to take the prep all the way to lingual and eliminate the flared margins. This gives the ceramist all the room necessary to create contour and transition that is lifelike.
Now look at the prep on the left and note the subtle differences.
