Background <p>Dentin hypersensitivity (DH) is a highly challenging and persistent dental complaint. This study aimed to evaluate the in vitro durability of the universal dentin bonding agents Single Bond Universal (SBU) and OptiBond Universal compared with a specialized desensitizer, Hybrid Coat (HC), and to assess the desensitizing efficacy of SBU and HC in vivo over a 1-year follow-up period.</p> Methods <p>Dental root samples were prepared and treated with the three agents. After 24&#xa0;h, 3 months, and 6 months, longitudinal sections of the root samples were examined under scanning electron microscopy, and adhesive layer thicknesses were measured. A split-mouth, blinded, randomized controlled trial was then conducted to compare the efficacy of SBU and HC for DH relief, using the visual analog scale (VAS). Assessments were performed at baseline, immediately post-application, and at 1, 3, 6, 9, and 12 months of follow-up, using standardized cold air stimulus protocols. The difference in VAS scores between pre- and post-application was used to measure efficacy.</p> Results <p>The adhesive layer created by SBU was thinner than that created by HC; however, the HC layer degraded more rapidly. After 6 months of water aging, root surfaces in the HC group were exposed, whereas those in the SBU group remained covered. The in vivo study demonstrated that SBU provided desensitizing efficacy comparable to that of HC over the 12-month period.</p> Conclusions <p>Within the limitations of the present study, it can be concluded that the universal bonding agent SBU is effective and durable when applied as a desensitizer. Its efficacy is comparable to that of a dedicated desensitizing treatment.</p> Trial registration <p>NCT07197437 (<a href="https://www.clinicaltrials.gov">https://www.clinicaltrials.gov</a>), Date of Registration: 15/09/2025. (Retrospectively registered).</p>