Bond Strength Evaluation of Three Commercial Self-Etch Adhesives on Dentine and Etched or Unetched Enamel

This in vitro study compared the micro-tensile bond strength (μTBS) of three self-etch adhesive systems (one one-step and two two-step systems) on different dental substrates. Twenty-seven molars were employed to expose flat dentine and enamel surfaces. They were equally distributed among experimental groups, according to three adhesive systems (Scotchbond Universal Adhesive (SUA), EnaBond SE (ESE), Clearfil SE BOND (CSE)), and among subgroups, according to three bonded substrates: etched enamel, unetched enamel, unetched dentine. In each subgroup, eighteen (n = 18) beam-shaped specimens were subjected to μTBS testing. Statistical analysis was performed using two-way ANOVA and Tukey’s tests. With both SUA and CSE, the µTBS values on etched enamel (respectively, 18.6 ± 4.2 MPa and 18.8 ± 2.5 MPa) were higher than those on the other substrates (p < 0.05). No statistically significant differences were observed when adhesives tested were compared to one another on etched enamel. On unetched substrates, ESE led to significantly increased µTBS mean values compared to the other systems. SUA showed its highest enamel μTBS when the enamel was etched. ESE showed the highest μTBS on unetched substrates while its performance on etched enamel was comparable to the other tested systems.