Adhesive Bond Integrity of Experimental Zinc Oxide Nanoparticles Incorporated Dentin Adhesive: An SEM, EDX, μTBS, and Rheometric Analysis

Abstract

Objective. Our study is aimed at preparing an experimental adhesive (EA) and assessing the influence of adding 5-10 wt.% concentrations of zinc oxide (ZnO) nanoparticles on the adhesive’s mechanical properties. Methods. Field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy were employed to investigate the morphology and elemental distribution of the filler nanoparticles. To examine the adhesive properties, microtensile bond strength (μTBS) testing, an investigation of the rheological properties, degree of conversion (DC), and analysis of the interface between the adhesive and dentin were carried out. Results. The SEM micrographs of ZnO nanoparticles demonstrated spherical agglomerates. The EDX plotting confirmed the incidence of Zn and oxygen (O) in the ZnO nanoparticles. The highest μTBS was observed for nonthermocycled (NTC) 5 wt.% ZnO group ( 32.11 ± 3.60 MPa), followed by the NTC-10 wt.% ZnO group ( 30.04 ± 3.24 MPa). Most of the failures observed were adhesive in nature. A gradual reduction in the viscosity was observed at higher angular frequencies, and the addition of 5 and 10 wt.% ZnO to the composition of the EA lowered its viscosity. The 5 wt.% ZnO group demonstrated suitable dentin interaction by showing the formation of resin tags, while for the 10 wt.% ZnO group, compromised resin tag formation was detected. DC was significantly higher in the 0% ZnO (EA) group. Conclusion. The reinforcement of the EA with 5 and 10 wt.% concentrations of ZnO nanoparticles produced an improvement in the adhesive’s μTBS. However, a reduced viscosity was observed for both nanoparticle-reinforced adhesives, and a negotiated dentin interaction was seen for 10 wt.% ZnO adhesive group. Further research exploring the influence of more filler concentrations on diverse adhesive properties is recommended.

Fiber post bonding with beta‐tricalcium phosphate incorporated root dentin adhesive. SEM, EDX, FTIR, rheometric and bond strength study

“…Regarding failure types at the interface, we observed cohesive failures (adhesive‐dentin) to be the most common in our study. Our study's findings confirmed the outcomes of earlier research in which adhesive‐dentin type failure was most frequently noted following the addition of filler NPs in the adhesive (Alfaawaz et al, 2022; Alqarawi et al, 2021). Given that bonding the adhesive with dentin is a challenging process, the collagenous composition of dentin and its moist environment may have played a significant role in observing this sort of failure (Peumans et al, 2005).…”

“…Regarding failure types at the interface, we observed cohesive failures (adhesive-dentin) to be the most common in our study. Our study's findings confirmed the outcomes of earlier research in which adhesive-dentin type failure was most frequently noted following the addition of filler NPs in the adhesive (Alfaawaz et al, 2022;Alqarawi et al, 2021).…”

A Comprehensive Narrative Review of Nanomaterial Applications in Restorative Dentistry: Demineralization Inhibition and Remineralization Applications (Part I)

“…Moreover, Alfaawaz et al [42] conducted an experiment wherein they developed an adhesive and examined how the addition of ZnO NPs at concentrations of 5-10 wt.% affects the mechanical properties of the adhesive. The addition of ZnO NPs at concentrations of 5 and 10 wt.% enhanced the adhesive's microtensile bond strength (μTBS).…”

“…The addition of ZnO NPs at concentrations of 5 and 10 wt.% enhanced the adhesive's microtensile bond strength (μTBS). Nevertheless, a decrease in viscosity was noted for both adhesives reinforced with NPs [42] According to a study conducted by Spencer et al [43], ZnO was added into Fuji Ortho LC (Tokyo, Japan) to produce mixes containing 13% ZnO and 23.1% ZnO. The adjusted adhesive agent was subjected to incubation with S. mutans for 48 hours in a diffusion disc experiment, which was employed to quantify the areas of bacterial suppuration.…”