In vitro wear of dual-cured bulkfill composites and flowable bulkfill composites

The objective of this study is to test the wear of dual-cured bulkfill and flowable bulkfill composites.

Six dual-cured bulkfill composites, Cention, Cention-Exp, Activa, Fill-up, Hyperfil Injectafill, and two flowable bulkfill composites Tetric Evoflow BulkFill and G-aenial Universal Flo were tested in this study (n = 8). Each composite was applied into an aluminum sample holder and cured with a Valo Grand (1230 mW/cm² ) or self-cured according to manufacturer's recommendations, and stored in water for 3 weeks. The samples were subjected to 120 000 load cycles of 49 N (CS-4) against spherical steatite antagonists and simultaneously subjected to 4440 thermocycles (5°C-55°C). At intervals between load cycles, polyvinyl siloxane impressions were taken and scanned with a True Definition Laser Scanner. The volumetric wear was calculated using image software (Geomagic). Microscopic images of selected wear facets and their corresponding worn antagonists were obtained using SEM. All data were analyzed using analysis of variance (ANOVA) and Tukey post hoc test for multiple comparison (α = .05; β = .2).

The load cycles volumetric wear-increase was linear. Two-way ANOVA showed significant main effects (material and light-cured) and significant interactions. Self-cured materials (mean = 0.38 mm³ ) showed more wear than light-cured materials (mean = 0.35mm³ ).

The bioactive materials except Activa light-cured showed significantly more wear than the flowable composites.

This study demonstrated that most of the dual-cured composites, if light-cured, showed the same wear as the flowable composites used as control. Therefore, to obtain adequate wear resistance the dual-cured composites should be routinely light-cured.