Zirconia Dental Implants: A Clinical, Radiographic, and Microbiologic Evaluation up to 3 Years

Purpose: To retrospectively evaluate the clinical performance of zirconia endosseous implants. Materials and Methods: Partially edentulous patients with adequate bone volume to fit yttria tetragonal zirconia polycrystal (Y-TZP) implants at least 3.5 mm wide and 8.0 mm long were included. Full-mouth probing pocket depth (PPDs) and percentage bleeding on probing (BOP) scores around teeth and implant(s) were assessed and compared. Marginal bone loss/gain relative to baseline was measured on intraoral radiographs, and the prevalence and quantities of seven periodontal bacteria were assessed around implants and teeth in the same patient. Results: Seventy-four consecutively treated patients with 121 zirconia implants (66 two-piece implants and 55 one-piece implants) were clinically evaluated after a mean observation period of 18 months. Three implants had failed and had been removed, for a cumulative implant survival rate of 96.5% (± 2.0%) after 3 years. The 118 surviving implants demonstrated healthy mucosal conditions, with low mean PPDs (1.8 ± 0.4 mm) and mean BOP scores (4.1% ± 4.2%). PPD and BOP were statistically significantly lower around implants than around teeth. BOP and PPD around implants and teeth were significantly correlated. Stable marginal bone levels were observed (mean bone loss of 0.1 ± 0.6 mm after 3 years). The frequency of isolation of all marker bacteria was similar at tooth and implant sites. Conclusion: Zirconia endosseous implants can achieve a 3-year implant survival rate in partially edentulous patients, similar to that of titanium implants, with healthy and stable soft and hard tissues. Keywords: clinical evaluation, dental implants, microbiology, peri-implant mucosa, zirconia