What is the most esthetic type of implant abutment available today?

One of the best products on the market today for custom zirconia abutments is the Atlantis Abutment system by Astra Tech. They use proprietary software to design each abutment specifically for the space and type of tooth to be replaced for optimized function and esthetics. They can be used with many implant systems, for any type of tooth, and use not only with zirconia, but titanium and other alloys can also be used to fabricate exactly the type of abutment you are requesting.