Purpose: The aim of this study was to investigate the effect of Prime & Bond adhesive on preventing postcementation hypersensitivity of vital abutment teeth restored with a full-coverage restoration using the immediate dentin sealing (IDS) technique. Materials and Methods: Twenty-five male patients received 25 three-unit fixed partial dentures. A split-mouth design was used and two vital abutment teeth in each patient were allocated randomly into Groups A or B. Teeth in Group A were treated with Prime & Bond using the IDS technique while teeth in Group B were used as a control and left untreated. The discomfort interval scale, ranging from 0 to 4, was adopted to evaluate hypersensitivity. The double-blind method was applied during the operation so that neither the patient nor the clinician knew which abutment had been treated. The sensitivity assessment was performed 1 week, and 1, 6, 12, and 24 months after cementation. Results were analyzed using the sign test. Results: Scores for teeth in Group A were statistically significantly lower than those in Group B at 1 week and 1 month postcementation (P .05), whereas there was no significant difference between Groups A and B at the end of 6, 12, and 24 months (P > .05). Conclusion: Preventive treatment with Prime & Bond using the IDS technique can significantly reduce postcementation hypersensitivity.