Clinical Performance of Zirconia Implant Abutments for Single-Tooth Implants

Objectives: The retrospective study evaluates the clinical performance of prefabricated zirconium-oxide implant abutments for the restoration of single-tooth implants in the anterior region.

Methods: Between July 2001 and December 2005, 34 patients (19 m/15 f) were restored with a total of 41 implants (Ankylos, Friadent, Germany). Implants were restored with prefabricated zirconium-oxide abutments (Cercon Balance, Friadent) and temporarily cemented all-ceramic crowns (Cercon, DeguDent, Germany). Restorations were re-evaluated in 12-month intervals. The survival (Kaplan-Meier) and success rates (success criteria according to Albrektsson et al., 1993) were evaluated. Frequency of prosthetic complications was documented, too. Subjective patient evaluation of the therapy was performed with a rank-scaled questionnaire covering esthetic quality, decision for repeated implantation, recommendation to other patients.

Results: Survival and success rate (Kaplan-Meier) was 100% after 48 months (mean clinical observation period: 34.6±22 months), prosthetic survival rate was 97.0%. After 15.5 months, 1 all-ceramic abutment fractured, probably due to unfavorable loading by a long clinical crown. Further prosthetic complications (2 cases with loss of retention) did not result in a replacement of the restoration. No fractures of structures or veneering ceramics were observed for the all-ceramic crowns. 97.1% of patients would certainly decide in favour of an implantation again (“Yes, maybe”=2.9%). 88.2% would unrestrictedly recommend implants while 11.8% answered “Yes, maybe”. Esthetic quality of the result was evaluated “very good” (76.4%) or “good” (23.6%).

Conclusions: Considering the survival rates of implants and prosthetic superstructures as well as the high patient satisfaction, the results of all-ceramic superstructures in the anterior region of the maxilla are promising. However, to avoid fractures, a careful indication is essential. Further clinical evaluations re. long-term performance are required.