Introduction: Teeth preparation for indirect restorations involves dentin exposure, which can induce tooth sensibility. Thus, it was suggested sealing exposed tubules with an adhesive that has to be sandblasted with aluminum oxide particles (AOP) in order to improve the wettability and therefore dental adhesion. Objective: To test the microtensile bond strength of immediate dentin sealing (IDS), after applying different types and sizes of aluminum oxide particles with different exposure times. Materials and Methods: Eighteen healthy molars received IDS technique after dentin exposure. They were randomly separated into six groups (n=3): divided following sizes and types of AOP (27μm, 30μm-silica-coated and 50μm) applied to the teeth's surface and exposure time to AOP (4 and 10 seconds). Eighteen resin composite discs were produced and luted to the teeth. Then, the specimens were cut in order to obtain sticks with 1±0.2mm2. These sticks were stressed to failure in tension using a universal testing machine. For the statistical analysis, ANOVA one-way and Tukey's HSD post-hoc test (p≤0.05) were used (SPSS 20.0). Results: The highest levels of adhesion were obtained in groups sandblasted with 30μm-silica-coated AOP (53.31MPa and 60.27MPa). No statistically significant differences were found between groups with different exposure times (p>0.05). Conclusion: Microtensile bond strength (μTBS) of immediate dentin sealing was influenced by different types of AOP. Clinical Implications: Sandblasting dentin's surface with silica-coated AOP after IDS technique acquires better bond strength values than other diameters or types of AOP. Schlagwörter: Surface treatment, aluminium oxide, IDS, bond strength, indirect restorations, sandblast, silica-coating