الفهرس 
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Abstract
Objective: The current study investigated the effect of different surface treatment and three types of self-adhesive (SA) resin cements on microtensile bond strength (μTBS) of indirect resin composite (IRC) blocks to dentin after aging with thermocycling. The ultra-morphology of the cements/dentin interface was investigated with scanning electron microscope (SEM). Materials and Method: Resin composite overlays (SR Nexco) were prepared. Their surfaces were ground with 600-grit SiC papers and randomly assigned to three different surface treatments: no treatment, silane application (Monobond Primer, IvoclarVivadentAGSchaan, Liechtenstein), or application of silane agent followed by topping with a dentin adhesive (Heliobond, IvoclarVivadentAGSchaan, Liechtenstein). The resin composite overlays were bonded to flat dentin surfaces of sixty extracted human third molars using a SA resin cements; either; RelyXUnicem, Multilink Speed or G-Cem, and etch-and-rinse (E&R) resin cement; Variolink N. The bonded assemblies were stored in water (24 h, 37 °C) and subsequently prepared for μTBS testing. All beams of approximately 0.9 mm2 were tested at dry and thermocycled (5.000, 5–55 ° C, 30 s) conditions and tested in tension at 0.5 mm/min in a universal testing machine (Instron, MA, USA). After μTBS test the beam was evaluated for fracture with SEM.
Results: The results of 3-way ANOVA test showed significant effect of the following factors; surface treatment, thermocycling of the specimens on bonding of IRC blocks to dentin (p<0.05). However the outcome of the ANOVA test revealed that the factor of resin cements type showed no significant effect on bond strength (p>0.05). Conclusion: The μTBS of the tested luting systems to dentin was material dependent and indicated that resin cement involving the SA technique provided reliable bonding compared to E&R luting agent.Despite the type resin cement used, surface treatment of IRC block play a great role in bonding effectiveness.Thermal cycling aging method significantly influences the bonding of resin cement to dentin.