摘要： Background: Laser irradiation modi?es the topography and composition of dentin surface aiming to increase the retention of bonded posts. Objective: To assess the effect of dentin irradiation with Er,Cr:YSGG or diode lasers on the bond strength of ?ber posts using self-adhesive resin cement. Materials and methods: Sixty bovine root canals were root-canal treated, post spaces were prepared, and subsequently ?ber posts were cemented. The samples were distributed according to the surface treatment: distilled water (control), Er,Cr:YSGG (1.5 W, 20 sec), or diode (1.5 W, 20 sec) lasers. Bond strengths were assessed by pull-out (n = 10) or push-out testing (n = 10). Pearson’s correlation was calculated. Failure mode after testing and the depth of tags in the dentinal tubules were analyzed by confocal laser microscopy. Data were submitted to analysis of variance and Tukey’s test. A p < 0.05 was considered signi?cant. Results: In the push-out test, Er,Cr:YSGG laser had signi?cantly different higher values (5.43 – 0.10 MPa) compared to the control (4.79 – 0.05 MPa). Diode laser values were not signi?cantly different from the other groups (5.12 – 0.27 MPa). In the pull-out test, there were no signi?cant differences between Er,Cr:YSGG (6.86 – 2.16 MPa) and diode (8.43 – 1.77 MPa) lasers, and both had signi?cant differences compared to the control (4.18 – 1.29 MPa). No correlation was found. Adhesive failures were predominant in all groups, and no signi?cant differences in tag penetration among the groups were found. Conclusions: The Er,Cr:YSGG laser increases the bond strength of resin cement and ?ber post to dentin in both tests, compared to control group without laser treatment. Diode laser only enhanced bonding for pull-out test.