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 35 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 3 months and were removed at least three times : 1 ) during the making of the impression ( 3 months after implant placement ) ; 2 ) when checking the zirconium core of titanium abutments at single crowns or the fitting of the metal structure at prostheses supported by multiple implants ; 3 ) at delivery of the definitive prostheses ( repeated disconnection or conventional loading group ) .