Two-piece Zirconia Implants Supporting All-Ceramic Crowns: Six-Years Results of a Prospective Cohort Study.

OBJECTIVES The aim of this prospective clinical trial was to present the 6-year outcomes of a two-piece yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) implant system in partially edentulous patients. MATERIAL AND METHODS Forty-nine two-piece zirconia implants were placed in 32 patients systemically healthy. Zirconia abutments were connected with adhesive resin cement. Single-unit full-ceramic crowns were cemented. The cases have been followed for an average of 82.2 ± 5.86 months after loading (range 74.93-92.26 months). RESULTS 24 participants with 39 implants were available for examination 6 years after loading. The cumulative implant survival rate was 83%. On an implant-level, the cumulative mechanical complication rate was 17.5%, the cumulative technical complication rate was 13%, the biological complication rate was 8%. After 6 years, subjects reported good satisfaction with the treatment: 3.7 ± 4.4 on a visual analog scale (VAS) from 0 to 100 mm. CONCLUSIONS Within the limitations of this prospective case series study, two-piece zirconia implants could offer an alternative for treatment of single edentulous spaces in the posterior region. The major complication on the long-term of this pioneering system was the abutment fracture, however due to the versatility of a two-piece implant system, replacement of the broken parts was possible.