Retrospective clinical evaluation of implant-supported zirconia fixed dental prostheses

Abstract: ABSTRACT  Purpose The aim of the present study was to evaluate the clinical outcomes of implant-supported restorations of zirconia.   Materials and methods This retrospective study included all patients rehabilitated with implant-supported fixed prostheses made of zirconia in a dental clinical private practice, based on data from patients’ dental records. Implant/prosthesis failure, marginal bone loss, and technical complications were the outcomes analyzed. Survival analyses were used to evaluate the associations between clinical covariates and the outcomes. Univariate and multiple linear model analyses analyzed the association of the marginal bone level (MBL) between the independent variables.   Results Ninety-four patients that received 244 implants supporting 143 fixed prostheses made of zirconia. The implants and the prostheses were followed up for a mean 26 and 20 months, respectively. Only one implant failed, placed in a fresh extraction socket, 27 days after installation. None of the prostheses failed. The most prevalent technical complication was loss/fracture of implant access hole sealing. Restoration chipping occurred in five veneered zirconia restorations, and none in monolithic zirconia prostheses. The cumulative survival rate with regards to restoration chipping was of 92.2% after 4 years. None of the nine independent variables presented a statistically significant hazard ratio (HR) in relation to restoration chipping in the univariate Cox proportional hazard models. Despite the univariate linear models suggesting that some of the independent variables might have an influence on the MBL over time, the results of the multiple linear regression model suggested that none of these predictor variables had a statistically significant influence on MBL.   Conclusions Implant-supported zirconia fixed dental prostheses showed a 100% survival rate in this short-term retrospective study. The cumulative survival rate (CSR) for restoration chipping was 92.2% after 4 years, with all the cases occurring in veneered zirconia restorations, although no variable presented a statistically significant HR on this outcome. None of the predictor variables had a statistically significant influence on MBL.