Decementation Rates and the Peri-Implant Tissue Status of Implant-Supported Fixed Restorations Retained via Zinc Oxide Cement: A Retrospective 10-23-Year Study.

Abstract

Long-term data on clinical outcomes of restorations attached to implants via zinc oxide (ZnO) cement have been sparse. The purpose of this study was to retrospectively investigate decementation rates and peri-implant tissue status of implant-supported fixed restorations retained by ZnO cement. Between 1989 and 2003, 63 partially edentulous patients received 93 implants. Of these, 27 patients received 36 screwed single crowns (SC) and served as a control (C group). The other 36 patients had their restorations cemented using ZnO cement. They were subdivided into a SC group and a fixed dental prosthesis (FDP) group. After between 10 and 23 years (mean: 13.22 ± 3.21), all decementation events and peri-implant soft tissue status were evaluated using patient records. Decementation was assessed in 57 implants supporting 30 SCs and 16 FDPs. Five cases of decementation (8.77%) were recorded after a mean of 9.27 ± 7.05 years (range: 4.81-21.79). In the control group of vertically screwed SCs, five events of screw loosening (13.89%) were recorded in five patients (18.52%) after a mean of 5.84 ± 5.96 years (range: 0.56-15.05) within a 14.30 year observation period. No cases of peri-implantitis were observed in any group. The mean values of periodontal probing depths and bleeding on probing (BOP+) were 3.74 mm and 31.58%, respectively, for ZnO-cemented restorations, versus 3.76 mm and 25%, respectively, for the C group. No significant correlations regarding technical/biologic complications between the groups were detected. Within the limitations of this study, we conclude that the use of ZnO cement provides sufficient retention of implant-supported fixed restorations over long periods without biologic complications in form of peri-implantitis.