Wear of Universal Restoratives

Objectives: The main portion of occlusal wear is believed to be "3-body" in nature. This kind of wear can be simulated with the ACTA wear machine. The aim of this study was to determine the 3-body wear of seven universal restorative materials and enamel: Filtek Z250 (3M; Z250), Filtek Universal Restorative (3M; FUR), Harmonize (Kerr; HMZ), TPH Spectra ST (Dentsply; TPH), Gradia Direct X (GC; GDX), Estelite Σ Quick (Tokuyama; ESQ), Activa (Pulpdent; ACV), and bovine enamel (E)
Methods: Consecutive wear rates (in µm/200,000 cycles per experiment) at five time moments (1 d, 4d, 1w, 1m, 2m) determined with the ACTA wear machine. Experimental conditions were (i) a slurry medium of rice/millet seed shells and (ii) chewing force and rotational speed were 15N and 1 Hz, respectively, and slip at the contact area was 15%. All surfaces were evaluated with Scanning Electron Microscopy (SEM).
Results: The table shows the consecutive wear in μm/200,000 cycles at five time moments. Statistically significant differences (two-way ANOVA) were found for the materials (P<0.001) the different time periods (P<0.001) and their interactions (P<0.001). Comparing the mean wear within day one resulted in the following ranking: Enamel < Filtek Universal Restorative < Estelite Σ Quick = Filtek Z250 < Harmonize < TPH Spectra ST < Gradia Direct X < Activa. A decrease of the mean wear was observed for most materials during in time. SEM showed different particle sizes of the composites and differnt wear patterns.
Conclusions: Low 3-body wear rates (<40 µm after 200,000 cycles) were observed for Filtek Universal Restorative, Estelite Σ Quick and Filtek Z250, while the wear rate of Activa was comparable with restorative Glass-Ionomer Cements