Zirconia (ceramic) has been used extensively in implants, and is clinically proven. To be sure, it hasn't been around as long as titanium, but that's just pedantry.

Titanium and zirconia both osseointegrate (bond to bone) extremely well. However, titanium is grey and this discoloration shows through gums. Zirconia is white - like a real tooth - so it's much better esthetically.

Some people turn out to be allergic to titanium. Zirconia is the best choice in such cases. (Zirconia is arguably the most biocompatible of all implant materials.)

There's a lot of medical literature about ceramic implants, but you can be assured that it's definitely at least on a par with titanium implants.