The aim of this in vitro study was to evaluate the microshear bond strength (μSBS) of resin composite to enamel
etching by Er,Cr:YSGG laser with the use of two differents adhesives systems. Fifty freshly extracted human molars
halves were embedded in acrylic resin before preparation for the study, making a total of up to 100 available samples.
The specimens were randomly assigned into six groups (η=10) according to substrate pre-treatment and adhesive system
on the enamel. A two-step self-etching primer system (Clearfil SE Bond) and a universal adhesive used as an etch-andrinse
adhesive (Adper Single Bond Universal) were applied to the nonirradiated enamel surface according to
manufacturer’s instructions, as control groups (Control CF and Control SB, respectively). For the other groups, enamel
surfaces were previously irradiated with the Er,Cr:YSGG laser with 0.5 W, 75 mJ and 66 J/cm2 (CF 5 Hz and SB 5 Hz)
and 1.25 W, 50 mJ and 44 J/cm2 (CF 15 Hz and SB 15 Hz). Irradiation was performed under air (50%) and water (50%)
cooling. An independent t-test was performed to compare the adhesive systems. Mean μSBS ± sd (MPa) for each group
was 16.857 ± 2.61, 17.87 ± 5.83, 12.23 ± 2.02, 9.88 ± 2.26, 15.94 ± 1.98, 17.62 ± 2.10, respectively. The control groups
and the 50 mJ laser groups showed no statistically significant differences, regardless of the adhesive system used. The
results obtained lead us to affirm that the bonding interaction of adhesives to enamel depends not only on the
morphological aspects of the dental surface, but also on the characteristics of the adhesive employed and the
parameters of the laser.