Influence of Low-Level Laser Modification and Adhesive Application Mode on the Bonding Efficiency of Universal Adhesives to Er:YAG Laser-Ablated Dentin

[摘要] Introduction: Erbium laser ablation as a method of tooth preparation and conditioning has shownpromising results. Although previous studies have adopted various combinations of different laserparameters and several dentin adhesive systems, very few have investigated combining high-leveland low-level ER:YAG lasers with Universal adhesives. This study aimed to assess the impact of usinglow-energy irradiation on the surface micro-topography and shear bond strength (SBS) of universaladhesive (UA) to the erbium:yttrium-aluminum-garnet (Er:YAG) laser-ablated dentin substrate,bonded in etch-and-rinse or self-etch adhesive mode.Methods: Eighty-seven extracted molars were sectioned to expose flat occlusal dentin surface; 60teeth were divided equally into three groups according to the surface treatment; bur-cutting (B),Er:YAG high-energy laser cutting (L1 - 200 mJ, 20 Hz, 50 μs pulse), or L1 followed by low-energylaser modification (L1/L2 - 80 mJ, 10 Hz, 50 μs pulse). Then each group was equally divided intotwo groups (n=10) according to the mode of application of the universal adhesive; either etch-andrinse (ER) or self-etching (SE). The samples were subjected to thermocycling (5000 cycle between5°C and 55°C), and SBS was tested. Two-way ANOVA and Tukey post hoc test were used to analyzethe results. The remaining 27 samples were used to investigate the effect of the treatment on thetopography of the treated dentin surfaces using a scanning electron microscope (SEM).Results: B/SE recorded the highest SBS (25.48 ± 2.6 MPa) followed by B/ER (23.20 ± 6.8 MPa) andL1/L2/SE (22.94 ± 4.1 MPa) and with no statistically significant difference between these groups (P>0.05). The lowest SBS results (P<0.05) were recorded for L1/SE (12.22 ± 3 MPa). No statisticaldifferences were found between the SBS of L1/L2/ER and L1/ER groups or between the SBS of L1/L2/ER and L1/L2/SE groups.Conclusion: A subsequent treatment of the Er:YAG laser-ablated dentin with low-energy lasermodification mode (LMM) enhances the SBS of the tested UA when applied in SE mode.

[学科分类] 基础医学

[关键词] Low-level laser;Er:YAG laser;Universal adhesives;Shear bond strength