Eighty patients requiring one single crown or one fixed partial prosthesis supported by a maximum of three implants were randomised , after implants were placed with more than @ Ncm , according to a parallel group design to receive definitive abutments which were loaded immediately ( definitive abutment or immediate loading group ) or transmucosal abutments which experienced delayed loading after @ months and were removed at least three times : @ ) during the making of the impression ( @ months after implant placement ) ; @ ) when checking the zirconium core of titanium abutments at single crowns or the fitting of the metal structure at prostheses supported by multiple implants ; @ ) at delivery of the definitive prostheses ( repeated disconnection or conventional loading group ) .