Surface Gloss, Radiopacity and Shear Bond Strength of Contemporary Universal Composite Resins

The surface gloss, radiopacity and enamel/dentin shear bond strengths (SBS)s of five commercially available contemporary universal composite resins (CR)s were examined. The tested universal CRs were as follows: G-aenial A'CHORD (GA), Charisma Diamond (CD), Neo Spectra (TM) ST(NS), Filtek(F) and Estelite Asteria(EA). Twelve cylindrical specimens per group were fabricated and gloss measurements were performed using a gloss meter after polishing and darkening. Five specimens of each group were radiographed using a CMOS sensor alongside an aluminum stepwedge, human enamel and dentin. The mean gray values were measured with a computer program. A total of 120 bonded human enamel and dentin specimens were subjected to SBS test. To analyze surface gloss, radiopacity and SBS we used Kruskall-Wallis, Wilcoxon signed rank, Welch tests and one-way ANOVA. Games-Howell, Tukey's HSD tests, and Dunn's multiple comparisons were used for multiple comparisons (p < 0.05). In terms of gloss units of the materials after polishing and darkening, the highest surface gloss was achieved with GA, followed by NS, F, CD and EA (p < 0.001). All the tested CRs showed significantly higher radiopacity values in comparison with dentin (p < 0.05). CD and NS presented higher radiopacity values, while other CRs were, in decreasing order; F, GA and EA (p < 0.001). The SBS ranking varied for enamel and dentin, and the adhesive failure was detected at a higher rate. Commercially available contemporary universal CRs display different surface gloss, radiopacity and SBS properties.