Effect of different adhesive strategies on microtensile bond strength of computer aided design/computer aided manufacturing blocks bonded to dentin

The aim of this study was to determine the microtensile bond strength(μTBS) of ceramic and composite computer aided design‑computer aided manufacturing (CAD‑CAM)blocks bonded to dentin using different adhesive strategies.
In this in vitro study, 30 crowns of sound freshly extracted human molars were sectioned horizontally 3 mm above the cementoenamel junction to produce flat dentin surfaces. Ceramic and composite CAD/CAM blocks, size 14, were sectioned into slices of 3 mm thick. Before bonding, CAD/CAM block surfaces were treated according to the manufacturer’s instructions. Groups were created based on the adhesive strategy used: Group 1 (GI) – conventional resin cement total‑etch adhesive system, Group 2 (GII) – conventional resin cement self‑etch adhesive system, and Group 3 (GIII) – self‑adhesive resin cement with no adhesive. Bonded specimens were stored in 100% humidity for 24h at 37°C, and then sectioned with a slow‑speed diamond saw to obtain 1 mm × 1 mm × 6 mm microsticks. Microtensile testing was then conducted using a microtensile tester. μTBS values were expressed in MPa and analyzed by one‑way ANOVA with post hoc (Tukey) test at the 5% significance le vel.
Mean values and standard deviations of μTBS (MPa) were 17.68 (±2.71) for GI/ceramic; 17.62 (±3.99) for GI/composite; 13.61 (±6.92) for GII/composite; 12.22 (±4.24) for GII/ceramic; 7.47 (±2.29) for GIII/composite; and 6.48 (±3.10) for GIII/ceramic; ANOVA indicated significant differences among the adhesive modality and block interaction (P Cementation of CAD/CAM restorations, either composite or ceramic, can be significantly affected by different adhesive strategies used.