A Comparison of Microtensile Bond Strength, Film Thickness, and Microhardness of Photo-Polymerized Luting Composites

• Published in: Materials Vol. 15; no. 9; p. 3050
• Main Authors: El-Askary, Farid, Hassanein, Abdullah, Aboalazm, Emad, Al-Haj Husain, Nadin, Özcan, Mutlu
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22.04.2022; MDPI
• Subjects: Bonding strength; CAD/CAM; CAD/CAM composite; Cement; Composite materials; Dentistry; Design optimization; dual-cured resin cement; Evaluation; Film thickness; Manufacturers; Microhardness; photo-polymerized composite; Polymerization; pre-heating; Rods; Viscosity; µ-tensile bond strength; United States > US; Japan; Germany; CAD/CAM composite; µ-tensile bond strength; film thickness; microhardness; photo-polymerized composite; dual-cured resin cement; pre-heating
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15093050

The aim of this study was to evaluate the effect of CAD/CAM composite thickness on micro-tensile bond strength (µTBS), microhardness (HV), and film thickness (FT) of different luting composites. Composite blocks (6.8 mm × 6.8 mm) were divided into 12 groups according to: CAD/CAM thickness and luting composite. For each group, 21 rods (1 mm × 1 mm) were tested in tension at crosshead speed of 1 mm/min. Fracture modes were categorized as adhesive, mixed, and cohesive. Microhardness (n = 5/group) was assessed using microhardness tester. Film thickness (12-rods/group) was evaluated using a stereomicroscope (×40). Data were analyzed using the two-way ANOVA/Tukey’s HSD test (p = 0.05). Parameters “thickness”, “cement”, and “thickness x cement” showed significant difference on µTBS and HV (p < 0.05). At 2 mm, heated x-tra fil composite showed the highest µTBS (45.0 ± 8.5 MPa), while at 4 mm thickness, Grandio Flow revealed the lowest µTBS (33.3 ± 6.3 MPa). Adhesive, mixed, and cohesive failures were reported. The HV of all composites decreased when photo-polymerized through 4 mm thickness (p < 0.05). Regardless of CAD/CAM thickness, photo-polymerized composites can be successfully used for luting CAD/CAM composite.