Dent Mater. 2023 Mar 13:S0109-5641(23)00063-5. doi: 10.1016/j.dental.2023.03.003. Online ahead of print.
OBJECTIVE: The objective of this study was to assess the influence of immediate dentin sealing (IDS) on the fatigue behavior of laminate occlusal veneers fabricated with CAD/CAM lithium disilicate ceramic and resin composite.
METHODS: Forty sound human molars were prepared and randomly divided into 4 groups (n = 10): RC-IDS+ (IDS and resin composite occlusal laminate veneer); RC-IDS- (resin composite occlusal laminate veneer without IDS); LD-IDS+ (IDS and lithium disilicate laminate veneer); LD-IDS- (lithium disilicate occlusal laminate veneer without IDS). The restorations were obtained using a digital workflow. After surface conditioning and bonding, thermocycling and accelerated fatigue tests (20 Hz, 5000 cycles with an initial load of 300 N, step-size of 100 N for 10,000 cycles, up to 1000 N, and then a step-size of 50 N until failure) were conducted. Fatigue data were recorded for both outcomes (crack or fracture) and statistically analyzed. Fractographic and adhesive interface analysis were conducted.
RESULTS: The indirect resin composite groups showed better fatigue behavior compared to lithium disilicate. IDS only had a positive effect for the survival of resin composite restorations for the ‘fracture’ outcome. Evident presence of micro-gaps at the adhesive interface in the LD-IDS- group could be noted.
SIGNIFICANCE: Immediate dentin sealing improved fatigue resistance behavior of resin composite occlusal veneers. However, this effect was not observed in lithium disilicate veneers.