Multicenter retrospective analysis of the ITI implant system used for single-tooth replacements: results of loading for 2 or more years.

This report involves the retrospective evaluation of ITI implants placed by a group of 12 clinicians located throughout the United States. Of the original 174 single implants placed in 129 patients reported previously, 157 were examined in 110 patients after 2 or more years (average 40.1 months). Twenty-two implants remained in the anterior and 135 implants (86%) remained in the posterior areas of the mouth, with 81 being restored with an octabutment screw-retained crown and 76 restored with a conical-abutment cemented crown (in function 2 years or longer). Occlusal screw loosening was observed in 22.2% of implants over both periods, with only 1 tooth loosening in both study periods (6 months to 2 years and > or = 2 years). Loosening of a solid conical abutment occurred in 1 additional patient, for cumulative conical abutment loosening of 5.3%. Significant radiographic bone loss was observed around 4 implants, with implant fracture noted with 3 additional implants (all mandibular first molars with hollow-screw or hollow-cylinder implant design). The survival rate at > or = 2 years was 95.5%. The data suggest that ITI implants can be a satisfactory choice for posterior single-tooth restorations.