I'm a general dentist in NZ and need to have a 5 unit non precious implant supported bridge (three implants 16 15 and 12 sites and none are parallel ) on paralleled custom abutments , the bridge is to be temp cemented onto the abutments and cross pin (screwed) from the palatal aspect . My technician is a brilliant master tech and has advised that the non precious is too hard to tap with his tap set - used conventionally on precious castings . My question is ; are there any pre manufactured non precious screw thread housings for cross pinning which can be cast onto , or burn out thread housings that could be cast ? Or are there other non precious components - screw and housing ( non precious cast on to ability ) that could be re purposed . The bridge is a very large framework and precious content cost has been rejected by the patient at this stage . Your thoughts would be appreciated .