How do you make root form implant temporaries?

There are a number of ways. The photo above was made by taking a fixture level open tray impression and having the laboratory fabricate a temporary bridge with root contours.

Usually when I am temporizing a single implant in the "esthetic zone"(From premolar-premolar) I use a prefab Ion crown that I attach to an implant part specially designed for a screw retained temporary. I customize the root portion using free hand composite material. It works nicely, but takes some chair time to fabricate properly.