Combining the effect of Gold Nanoparticles with Diode or Er. Cr:YSGG Laser on the Bond Strength of Etch- and- Rinse Adhesive applied to Dentin Surface

Background: This research was carried out to evaluate the impact of various forms of laser irradiation and gold nanoparticles on the bond strength of etched and adhesive-treated dentin. Forty-five extracted human upper molars had their crowns removed, and standardized cavities (3×3×3 mm) were prepared on the buccal and lingual surfaces. Samples were divided based on adhesive technique and subjected to various laser treatments, with and without gold nanoparticles. Surface hardness was measured using a Vickers hardness tester, surface roughness with a universal testing machine and nanoparticle penetration depth via scanning electron microscopy. Results showed that laser application combined with gold nanoparticles enhanced adhesive penetration into dentinal tubules, improving bond strength and durability. Group C1 showed the highest surface roughness, groups A0 and C0 had the greatest nanoparticle penetration, while B0 and D0 had the lowest. Laser irradiation, after adhesive application especially with gold nanoparticles promoted deeper material diffusion into dentin and increased both surface hardness and roughness. In conclusion, combining laser treatment with gold nanoparticles improved dentin surface characteristics and adhesive penetration, significantly enhancing restoration performance and longevity. This technique represented a promising advancement in adhesive dentistry, potentially leading to stronger and long lasting dental restorations with better clinical outcomes.