1 Department of Fixed and Removable Prosthodontics, Centre for Dentistry and Oral Hygiene, University Medical Center Groningen, The Groningen, the Netherlands.
2 Department of Medical and Oral Microbiology, Centre for Dentistry and Oral Hygiene, University Medical Center Groningen, The University of Groningen, Groningen, the Netherlands.
Conflict of interest and source of funding:
This study was financially supported by a grant from ZV3 (Wolfratshausen, Germany) and by the authors institutions. The authors declare that they have no conflicts of interest.
Aim: To evaluate the clinical performance of zirconia endosseous implants in a retrospective study.
Materials and Methods: A cohort of 157 consecutively treated patients (n=316 zirconia implants) was studied through chart review and clinical examination. Seventy-two patients (n=147 implants) could be clinically examined. Full mouth Probing Pocket Depth (PPD) and percentage Bleeding on Probing (BOP) 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 7 periodontal bacteria were assessed around implants and teeth in the same patient.
Results: After a mean observation period of 30 months, 15/316 implants had failed, to a cumulative chance on implant survival (one piece and two piece implants) of 93.4% (SE 1.8%) after 5 years. Nine one piece implants had fractured. They had been milled from a batch of rectangular unilaterally pressed zirconia blancs. There were no fractures in two piece implants. Two piece Implants survival rate 96.9% (SE 2.2%) after 5 years.
Surviving implants demonstrated healthy mucosal conditions with low mean PPD’s (1.7 mm, s.d. 0.4) and mean BOP (3.7%, SD 5.4%). PPD and BOP were statistically significantly lower in implants than in teeth. BOP as well as PPD around implants and teeth correlated significantly (r=0.56, p<0.001; r=0.51, p<0.001); Stable marginal bone levels were observed with a mean of 0.0 mm (SD 0.4 mm) bone loss after 5 years. Bacterial counts were consistently lower on teeth than on implants, although not to a statistically significant level.
Conclusion: Zirconia endosseous implants can achieve a 5-year implant survival rate in partially edentulous patients, similar to that of titanium implants, with healthy and stable soft and hard tissues.