Background: Dentin hypersensitivity is a common clinical condition that frequently develops following tooth preparation, gingival recession, and cervical dentin exposure. High-power diode lasers have emerged as an effective modality for dentin desensitization by promoting dentinal tubule occlusion while minimizing pulpal injury. However, laser-induced morphological alterations may influence subsequent adhesive procedures, particularly the bonding of resin cements to dentin. Although previous investigations have evaluated the effect of diode laser desensitization on bond strength, limited evidence exists regarding the ideal waiting period between laser treatment and definitive adhesive cementation.

Objective: To evaluate the effect of different time intervals following 980-nm diode laser desensitization on the shear bond strength of a self-adhesive resin cement to dentin.

Materials and Methods: Sixty freshly extracted human premolars were prepared to expose flat coronal dentin surfaces. All specimens received diode laser desensitization using a 980-nm diode laser at 1.0 W in continuous mode for 20 seconds. Specimens were randomly allocated into three groups (n = 20) according to the interval between laser treatment and bonding:

·         Immediate bonding (within 30 minutes)

·         Bonding after one week

·         Bonding after two weeks

RelyX U200 self-adhesive resin cement was bonded to dentin using standardized cylindrical molds. Shear bond strength testing was performed using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed using SPSS Version 23. Normality was assessed using the Shapiro-Wilk test. Intergroup comparisons were performed using non-parametric statistics with statistical significance set at p < 0.05.

Results: The one-week group demonstrated the highest mean shear bond strength (12.67 ± 3.62 MPa), followed by the two-week group (10.60 ± 5.25 MPa) and the immediate bonding group (9.93 ± 3.38 MPa). Pairwise comparisons revealed significantly greater bond strength in the one-week group compared with immediate bonding, whereas no significant difference was observed between the immediate and two-week groups. These findings indicate that delaying bonding for one week after diode laser desensitization provides a more favourable substrate for resin cement adhesion than immediate or two-week delayed bonding.