A universal adhesive containing copper nanoparticles improves the bonding and mechanical properties of resin cement–root dentin interface: an in vitro study

Abstract

The aim of this study was to evaluate the anti-MMP activity of two concentrations of copper nanoparticles (CuNp) and the effect of their addition to a universal adhesive system on resin cement-radicular dentin in situ degree of conversion (DC), elastic modulus (EM), nanoleakage (NL), and push-out bond strength (PBS). Anti-MMP activity was evaluated for several MMPs. Seventy-two roots of endodontically prepared human lower premolars were randomly divided into six groups according to CuNp concentration (0% [control], 0.1%, 0.2%) and adhesive strategy (etch-and-rinse [ER] and self-etch [SE]). Fiber posts were cemented, DC was measured using micro-Raman spectroscopy, the EM of the hybrid layer and adhesive layer was measured using a nano-indenter, the NL was evaluated by scanning electron microscopy, and PBS was tested at 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey’s test (α = 0.05). CuNp demonstrated anti-MMP activity (p < 0.01). CuNp containing-adhesives showed significant increased DC (p = 0.01), increased EM in the hybrid layer and adhesive layer (p = 0.001), decreased NL values (p = 0.001), and increased PBS (p = 0.0001). Adhesive strategy was not statistically significant (p > 0.47). Usually, a significant difference among root thirds was observed, except for DC and NL when CuNp 0.2% was evaluated. This is the first in vitro study showing that the incorporation of CuNp in an adhesive is an achievable alternative that can provide anti-MMP activity and improve the mechanical and bonding properties to root canal dentin.

Keywords:

• Universal adhesive system
• copper
• nanoparticles
• push-out bond strength
• nanoleakage
• metalloproteinases

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was partially supported by the National Council for Scientific and Technological Development (CNPq) [grant 308286/2019-7] and the Coordination of Improvement of Higher-Level Personnel (CAPES) [Finance Code 001] (Brazilian agencies).