Zirconia abutments for single-implant crowns appear to demonstrate good short-term technical and biological results, according to a team of researchers from Norway and Sweden (Clinical Oral Implants Research, March 8, 2011).
The study comprised two parts: Part one was a retrospective evaluation of records of 130 patients treated with 185 single-tooth implant restorations using zirconia abutments. Part two involved clinical exams of 25 patients with 40 restorations placed more than three years prior. The restorations were either an all-ceramic crown for cementation or a screw-retained, one-piece restoration with the veneering porcelain baked directly to the zirconia abutment.
In part one of the study, the researchers found that the zirconia abutments performed well over the follow-up period. The rates of both technical and biological complications were low, and the patients were in general extremely satisfied with the restorations. No all-ceramic crowns fractured during the observation period, but two abutments did.
In part two, they found no significant differences for changes in any of the soft-tissue registrations or the peri-implant marginal bone level between the conventional two-piece abutment–crown restoration and the one-piece restoration. In addition, they found only small changes (mean 0.29 mm) in the peri-implant bone level changes from placement to the clinical exam three to five years later.
