Introduction: Advances have been made in the composition of flowable composites in recent years and self-adhering composites, which do not require a bonding agent, have recently been introduced to the market. This study aimed to assess the microshear bond strength (μSBS) of a self-adhering flowable composite (Vertise) to primary enamel treated with a graphite disc with silicon carbide particles (SIC) and laser irradiation, the result of which was compared to that of a conventional flowable composite (Premise).Methods: In this in vitro, experimental study, 72 samples of sound primary enamel were evaluated. A smooth enamel surface was obtained using a graphite disc. Next, the erbium chromium yttrium scandium gallium garnet (Er,Cr:YSGG) laser was used for enamel surface treatment in half of the samples (n = 36). All the samples were then randomly divided into 4 groups of (i) Premise flowable composite (PF) without laser (n = 18), (ii) Vertise flowable composite (VF) without laser (n = 18), (iii) PF with laser (n = 18), and (iv) VF with laser (n = 18). The teeth were then incubated at 37°C for 24 hours and were then subjected to thermocycling. The μSBS of samples was measured using a universal testing machine and reported in megapascal (MPa). Data were analyzed using SPSS via the two-way ANOVA and independent-samples t test at P < 0.05.Results: The mean μSBS of VF was significantly higher to the laser-treated samples (13.60 ± 5.47) compared with the non-treated samples (5.89 ± 2.42) (P < 0.001). However, no significant difference was noted in the μSBS of PF to the laser-treated (13.18 ± 3.45) and non-treated samples (16.06 ± 3.52) (P = 0.058).Conclusion: The μSBS of the conventional flowable composite is higher than that of the self-adhering flowable composite to the enamel of primary teeth. Enamel surface treatment with laser irradiation increases the μSBS of self-adhering flowable composites
