Evaluation of Correlation Between Wear Resistance and Microhardness of Resin-based CAD/CAM Blocks

Abstract

Aim: Evaluating the relation between wear resistance and microhardness of composite blocks, hybrid block, and resin composite to provide convenient argument for clinical application.Methods: A conventional resin composite (IPS Empress Direct, Ivoclar Vivadent, Liechtenstein), a hybrid ceramic block (Enamic, Vita, Germany), and composite blocks (Lava Ultimate, 3M, USA; Hc block, Shofu, Japan; Brilliant Crios, Coltene, Switzerland; Cerasmart, GC Corp., Japan) were investigated. Specimens (n=12 for each) were loaded in a chewing simulator (Dent Ar-Ge, Analitik Medical, Turkey) for thermal cycling (49 N force, 240.000 cycles, 1.5 mm lateral movement, 1.7 Hz frequency) and worn sufaces were scanned with Las-20 (Laser scanner, SD-Mechatronic, Germany), and Vickers microhardness (VHN) values were determined (200 grf/10 sec). Statistical analysis was performed using Spearman Correlation Coefficient, Kolmogorov-Smirnov, Mann-Whitney U, Friedman and Kruskal-Wallis tests (p<0.05).Results: Significant correlation was detected between microhardness and wear resistance for all composite Cad/Cam blocks (p<0.001), whereas no correlation was observed for hybrid block and resin composite material (p≥0.05). Vita Enamic showed the highest VHN value and wear resistance among all the materials (p<0.001). Conclusion:Within the limitations of this in vitro study, a significant correlation between microhardness and wear resistance was observed only for composite Cad/Cam blocks which varied among the brands used in this study.