Effect of ultrasound on preheated resin composites used as ceramic luting agents

This study investigated the effect of ultrasound application when luting ceramic using two preheated composites that show distinct responses to preheating at 69°C: Filtek Z100 and Z350XT. RelyX Veneer was the control. Feldspar disks were luted using the resin-based luting agents (RBLAs), and ultrasound was tested. Biaxial flexure strength (σ_bf) was calculated at z-axial positions of the luted disks (z=0; z=-t₂). Microtensile bond strength (μTBS) to ceramic was tested (n=30). Data were analyzed at α=0.05. At z=0, the σ_bf was higher for Z350 when ultrasound was not used. When ultrasound was applied, the σ_bf was similar between Z350 and Z100. At z=-t₂, differences across the RBLAs were observed: Z350 was superior than Z100 and control without ultrasound. Ultrasound increased σ_bf for Z100 at both axial positions. The preheated composites yielded higher μTBS than the control. Ultrasonication increased the mechanical performance of ceramic luted with Z100 without influencing the film thickness.