BACKGROUND: Effective and durable bonding of immediate dentin sealing (IDS) is a crucial factor in the success of adhesive-bonded restorations. This study aimed to investigate the influence of chlorhexidine (CHX) and benzalkonium chloride (BAC) pretreatments on the immediate and aged bond strengths of a universal adhesive used in IDS across two etching modes. METHODS: Flat dentin surfaces were obtained from 120 molars and divided into six groups based on pretreatments (no treatment, CHX, and BAC) in two etching modes (etch-and-rinse (E&R) and self-etch (SE)) using All Bond Universal, in conjunction with a hydrophobic resin layer. Following the provisional stage and resin cementation, immediate and aged shear bond strengths (SBS) were measured after 24 h and 1 year of storage, respectively. The data (in MPa) were analyzed using ANOVA and Tukey tests (p <
0.05). RESULTS: CHX pretreatment did not significantly impact bond strengths, while BAC pretreatment led to a significantly lower immediate SBS in the SE mode (9.91 ± 1.93 MPa) compared to the control group (16.07 ± 3.45 MPa, p <
0.001). In the E&R mode, no statistically significant differences were found among the three pretreatment groups at either storage time (p >
0.05). After one year, SBS values in the SE mode decreased for all groups, with the CHX group showing the lowest value (9.98 ± 3.91 MPa), though these reductions were not statistically significant (p >
0.05). In contrast, SBS values in the E&R mode remained stable or slightly increased, with the BAC group reaching 17.12 ± 4.05 MPa after one year. Aged SBS values in the E&R mode were significantly higher than in the SE mode for the CHX (16.53 ± 2.28 MPa vs. 9.98 ± 3.91 MPa, p <
0.001) and BAC groups (17.12 ± 4.05 MPa vs. 10.55 ± 3.03 MPa, p = 0.001). CONCLUSION: CHX and BAC pretreatments did not offer additional advantages in terms of long-term bonding performance in IDS with the universal adhesive utilized in this study. When using antibacterial agents, All Bond Universal adhesive in E&R mode could provide better long-term bonding performance than that of its SE mode.