Materials and methods: Forty-nine patients (mean age 54 +/-13 years) received 49 metal-based fixed partial dentures randomly luted using zinc-phosphate (ZPC) (Richter&Hoffmann, G) or self-adhesive resin cement (Rely X Unicem (RXU) encapsulated, 3M Espe, G) at the University Medical Center of Regensburg. There were two onlays, 42 posterior and 5 anterior crowns. Forty-seven restorations were made of precious alloys, 2 of non-precious alloys. The restorations were examined immediately after cementation and then every year. The clinical performance was checked according plaque (0-5; PI, Quigley -Hein)- bleeding- (0-4; PBI; Mühlemann) and attachment scores. The examination included pulp vitality and pain percussion tests. Statistics: means of scores, std.dev. cumulative survival and complication rates were calculated using life tables.
Results: The mean observation time was 3.16 +/-0.6 years (min: 2.0; max: 4.5 years). During that time no restoration was lost, no re-cementation became necessary. One endodontic treatment was performed at the self-adhesive composite group after 2.9 years. Bleeding (1.44 RXU vs. 1.25 ZOC) and plaque (1.64 RXU vs. 1.0 ZPC) scores showed no statistically significant difference. Pulp vitality and pain percussion tests were not different.
Conclusion: The self-adhesive- resin cement RelyX Unicem performed clinically as well and can be used as easily as zinc phosphate cement to retain metal-based restorations over a 38-month observation period.