SURFACE GLOSS, RADIOPACITY and SHEAR-BOND STRENGTH of a NEWLY MARKETED UNIVERSAL NANOHYBRID COMPOSITE RESIN

Objectives: To evaluate the surface gloss, radiopacity and shear bond strength (SBS) of a newly marketed universal nanohybrid composite resin (CR) (Gaenial A’CHORD) comparing with four commercial universal CRs including two nanofilled and two nanohybrid.
Methods: The tested universal CRs were as follows: G-aenial A’CHORD(GA), Charisma Diamond (CD), Neo Spectra^TMST (NS), Filtek (F) and Estelite Asteria (EA). Twelve disk-shaped specimens per group were fabricated for surface gloss measurements and evaluations were performed after polishing and darkening using a gloss meter. Five specimens of each group 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 Kruskall-Wallis, Wilcoxon signed rank, Welch and one-way ANOVA tests were used. Games-Howell, Tukey’s HSD tests, and Dunn’s multiple comparisons were used for multiple comparisons (p<0.05).
Results: 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, EA, respectively (p<0.001). All the tested CRs showed significantly higher radiopacity values in comparison with dentin (p<0.05). CD and NS presented higher values of radiopacity, while other CRs were in decreasing order: F, GA, EA (p<0.001). SBS ranking for enamel was as follows: GA≥EA≥F>NS≥CD and for dentin: F≥GA≥EA≥CD>NS.
Conclusions: The new universal CR, GA is particularly promising with its superior surface gloss, sufficient bonding properties to enamel and dentin and also demonstrated an adequate level of radiopacity.