Microshear Bond Strength, Ultramorphological, and Elemental Assessment of Gold–Silver Nanoparticle-treated Dentin Bonded to Resin Composite with Different Adhesive Modes

Abstract

The aim of the present study is to evaluate the effect of Ag-Au NPs formulation as surface pretreatment by assessing the microshear bond strength, ultra-morphological, and elemental characteristics of gold-silver nanoparticle-treated dentin to resin composite with different adhesive modes. A total of 60 extracted sound human permanent molars were selected to test the microshear bond strength of composite resin to dentin (40 teeth) and 20 molars were used to assess the ultramorphological and elemental characteristics of silver-gold nanoparticles using environmental scanning electron microscope (ESEM) with energy-dispersive X-ray (EDX) analyzer. The specimens were randomly divided into two main groups according to measured tests either microshear bond strength or elemental analysis. For the bond-strength testing group, 40 teeth were equally distributed into two main groups (20 each) according to dentin-surface pretreatment with or without the use of silver-gold nanoparticles. Then, each group was further divided into two subgroups (10 specimens for each) according to adhesive mode. For ultramorphological and elemental analysis, 20 teeth were equally divided into similar previously mentioned groups according to treatment modalities (5 teeth per group). The multimode bonding agent used in this study was single-bond universal, 3M. The data were collected and statistically analyzed. The significance level was set at p ≤0.05. The results showed that different etching modes had no statistically significant effect. Also, pretreatment had no statistically significant effect. The interaction between the two variables also had no statistically significant effect. Majority of samples in all groups had mixed failure mode. Ultramorphological examination of the tested samples treated with silver-gold nanoparticles revealed proper dispersion of nanoparticles in dentin. The new formulation of silver-gold nanoparticles did not interfere with the bond strength and sealing ability of resin composite restoration in different adhesion modes. The cavity disinfection with silver-gold nanoparticles did not affect the marginal integrity of resin composite restoration. Further studies should be done to evaluate the impact of application of silver-gold nanoparticles in long duration with other adhesive systems in the clinical scenario.