Assessment of the Physical Properties of an Experimental Adhesive Dentin Bonding Agent with Carbon Nanoparticles

Abstract

The present study was aimed at reinforcing the control adhesive (CA) with two concentrations (2.5% & 5%) of carbon nanoparticles (CNPs) and evaluating the impact of these additions on the adhesive’s properties. Scanning electron microscopy (SEM) and energy dispersive X-Ray (EDX) spectroscopy were utilized to examine the morphological characteristics and elemental mapping of the filler CNPs. To investigate the adhesive’s properties, rheological assessment, shear bond strength (SBS) testing, analysis of the adhesive–dentin interface, degree of conversion (DC) analysis, and failure mode investigations were carried out. The SEM micrographs of CNPs verified roughly hexagonal-shaped cylindrical particles. The EDX plotting established the presence of carbon (C), oxygen (O), and zirconia (Zr). Upon rheological assessment, a gradual reduction in the viscosity was observed for all the adhesives at higher angular frequencies. The SBS testing revealed the highest values for 2.5% CNP adhesive group (25.15 ± 3.08 MPa) followed by 5% CNP adhesive group (24.25 ± 3.05 MPa). Adhesive type interfacial failures were most commonly found in this study. The 5% CNP containing adhesive revealed thicker resin tags and a uniform hybrid layer without any gaps (compared with 2.5% CNP adhesive and CA). The reinforcement of the CA with 2.5% and 5% CNPs augmented the adhesive’s bond strength. Nevertheless, a diminished viscosity (at higher angular frequencies) and reduced DC were observed for the two CNP reinforced adhesives. CNP reinforced dentin adhesives are effective in enhancing the adhesive bond integrity of resin to dentin.