Microshear Bond Strength of a Self-adhesive Composite to Erbium Laser-Treated Primary Enamel

Abstract

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 selfadhering flowable composite to the enamel of primary teeth. Enamel surface treatment with laser irradiation increases the µSBS of self-adhering flowable composites.