So you’re ready to restore an implant in the esthetic zone. But you’re feeling like a Super Dentist, so you want to make this look as nice as possible.
Well if you used a great implant surgeon, the implant was placed in a prosthetically-driven manner. And if you use a great lab, the porcelain will look beautiful. What is there to do for the restorative dentist? Just take the impression and record the shade?
Nope. We can develop the emergence profile of the restoration to mimic that of a natural tooth. The implant is a circle. The cross section of a natural tooth subgingivally is definitely not a circle.
Have you ever taken an impression of a circular implant with a circular impression coping and sent it to the lab? Do you know what most good labs will do? They develop the emergence profile for you. They add porcelain subgingivally. They have to do this because they need to transform a circle shape into a tooth shape by the time it emerges from the gingiva. If they didn’t do this, the restoration would look silly at first, trap food and debris more easily, and then look terrible if any gingiva recede.
So you go to seat the final restoration and the patient says, “Ow!” This is because you’re expanding the tissue too quickly from the shape of the circular healing abutment into the tooth shape created by the lab. Not only can it be uncomfortable, but it can lead to unpredictable results. If you are able to put final torque on the abutment screw, you can run into two problems:
(1) The tissue is so tight that you can’t easily seat the crown. More discomfort or even de-cementation of a cementable crown.
(2) Months later the patient returns with gingival recession. Oops. You placed too much pressure on the gingiva, it blanched too much, possibly became necrotic, and receded.
So the best thing to do when a patient is ready for an impression is to not take the impression. Seat a temporary abutment and begin to slowly develop an emergence profile. Here’s how:
(1) Paint acrylic or flowable composite onto the abutment into one of the shapes in the figure above. Central and lateral incisors have more of a triangular shape than circular.
(2) Try the restoration in and look for blanching of the tissues. If it lasts longer than 5 minutes, you have probably over-contoured. Reduce!
(3) Avoid sharp angles and ridge laps; these will accumulate plaque.
In the figure above, the provisional on the left demonstrates a lack of transition from the platform to the tooth as it emerges from the gingiva. On the right, flowable composite has been added to ease this transition and begin to shape the surrounding gingiva.
(4) Reappoint about every two weeks. Add and subtract as necessary. After 4-6 weeks, you should have a good idea of where the tissue will stay and can now take your final impression.
Notice the triangular shape of the gingiva; this correctly resembles the emergence profile of a lateral incisor. We are supporting the papilla and facial ginigva the same way they will be supported with the final restoration. No surprises.
But how do we relay these gingival contours to the lab? We can’t just take a circular impression coping and rush to squirt impression material. The gingiva begins to collapse immediately, especially the deeper the placement of the implant. In the next post, I’ll show you how to make a custom impression coping.