Bond strength to dentin of primary teeth irradiated with varying Er:YAG laser energies and SEM examination of the surface morphology

BACKGROUND AND OBJECTIVES: This study aimed to assess in vitro the influence of Er:YAG laser energy on the shear bond strength of a total-etch adhesive to lased dentin of primary teeth, and observe under SEM the morphological appearance of laser-ablated dentin surfaces. STUDY DESIGN/MATERIALS AND METHODS: For SBS, specimens were irradiated with the energies 60 mJ/2 Hz (G2), 80 mJ/2 Hz (G3), 100 mJ/2 Hz (G4). Control (G1) was not irradiated. Dentin surfaces were acid-etched, Single Bond adhesive (3 M) was applied, and resin cylinders were fabricated from Z250 resin (3 M). Bond strength was tested in shear (0.5 mm/min). For morphological analysis, specimens were irradiated using the same energies, either or not acid-etched, and observed by SEM. RESULTS AND CONCLUSIONS: SBS means, in MPa, were: G1-17.89(+/-4.75); G2-12.34(+/-4.85); G3-10.30(+/-3.67); G4-10.41(+/-4.20). Overall, Er:YAG laser irradiation of primary teeth dentin, prior to the adhesive protocol, adversely affected bond strength. Furthermore, it was noticed that even though there was no significant difference among the Er:YAG laser-treated groups, the increase of laser energy resulted in increasingly cratered surfaces, regardless of acid-etching association.