Well I've been wading through a lot of websites from a wide variety of sources in order to build the most complete picture possible, and my assessment is that any work on the bone is highly likely to cause an immune response at some point in the patients life, and generally sooner rather than later whether titanium or zirconium... I'm afraid I'm just not prepaired to pay that amount of money for "treatment" that permanently alters bone structure thereby creating the likelihood of an unwanted immune response.
So, the only option is a bridge of which the encore appears to be a non-starter due to grinding perfectly healthy teeth, the maryland which has metal wings is not sounding very good due to the metal.... leaving either a temporary tooth attached to some plastic that is moulded to fit the mouth or the maryland which is much more practical but ofcourse has metal, unless ofcourse there is a non-metallic maryland bridge! the holy grail?? :)