Long-Term Evaluation of One-Piece Versus Two-Piece Zirconia Dental Implants: Retrospective Study Up to 10-Year Follow-Up

Objectives: The aim of this retrospective study was to evaluate the long-term clinical and radiographic performance of zirconia dental implants with one-piece and two-piece configurations supporting single-tooth restorations. The primary outcome was implant survival, while the secondary outcome was the assessment of interproximal marginal bone loss (MBL) over time. Materials and methods: A total of 67 implants placed in 55 patients were included, with a mean follow-up of 60.6 months. Forty-five implants were one-piece systems and twenty-two were two-piece systems. All surgical and prosthetic procedures were performed by the same operator, following the manufacturer’s recommendations. Final restorations were delivered three months after implant placement. Marginal bone levels were assessed radiographically at the time of definitive prosthesis delivery (T0) and at the last follow-up examination (T1). Statistical significance level was set at 5% (α = 0.05). Results: The overall implant survival rate was 100% in both groups. One-piece implants showed higher initial MBL values than two-piece implants; however, bone level changes over time were limited in both configurations, with no significant intra-group differences between T0 and T1. Conclusions: Both implant configurations showed excellent clinical and radiographic outcomes, with a 100% survival rate and limited marginal bone loss during long-term follow-up. Marginal bone levels appeared to be influenced more by implant neck design than by implant configuration, suggesting that zirconia implants with a smooth transmucosal design may represent a reliable metal-free option for single-tooth rehabilitation in properly selected patients.