Two- And Three Body Wear Of Bulk Fill Composites

Objectives: Sculptable bulk fill restoratives are becoming more and more popular. Their main application is load bearing posterior restorations, where wear resistance is important. In general, two body wear (2BW, restoration and antagonist) and three body wear (3BW, restoration, food bolus and antagonist) can be distinguished. The objective of this study was to characterize and compare 2BW including wear of the antagonist, and 3BW of dental bulk fill composites based on different filler technologies.
Methods: 3BW (ACTA method) was performed according to ISO/TS14569-2 (200,000 cycles) relative to Filtek^TM Z250 (3M Oral Care). 2BW (pin on disk, Elcometer 1720, Elcometer Limited) was determined on composite plates polished with P4000 sandpaper (Buehler) using steatite spheres as antagonists (6mm diameter, load 5N, 10mm lane, 120 cycles/min). Volume loss (Vloss) of 2BW pattern on samples and Steatite antagonists after 14,400 cycles was measured via laser scanning microscopy (Keyence). All specimens were cured according to manufacturers’ instructions.
Results: ANOVA analysis (Tukey) showed that at p<0.05, behavior of bulk fill composites can be very different for 2BW (n=4) and 3BW (n=2). The letters in parenthesis indicate which samples are statistically not different within the same column. No correlation was found between 2BW and 3BW (linear, p=0.76).
Conclusions: Because there is no correlation between 2BW and 3BW, both wear test methods need to be done to gain a comprehensive understanding of wear resistance. Overall, Filtek^TM Bulk Fill Posterior and Filtek^TM One showed lowest 3BW and 2BW, including wear of the antagonist. This may be attributed to 3M’s nanofiller technology. SonicFill^TM 2 was the only nanohybrid comparable to the nanocomposites.