This study aimed at investigating the effect of a
methacrylate-modified chitosan on the durability of adhesive
interfaces to improve the clinical performance of dental
restorations. Chitosan was modified with methacrylic acid
(Chit-MA70) on 16% of the amino groups. Viscosity,
rheology, and 1
H NMR spectroscopy were performed to
characterize the modified polysaccharide. Chit-MA70 was
blended into a primer of an “etch-and-rinse” experimental
adhesive system and tested on human teeth. The presence of
methacrylate moieties and of residual positive charges on the
polysaccharide chain allowed Chit-MA70 to covalently bind to
the restorative material and electrostatically interact with demineralized dentin. The Chit-MA70 containing an adhesive system
showed values of the immediate bond strength (26.0 ± 8.7 MPa) comparable to the control adhesive system (25.5 ± 8.7 MPa).
However, it was shown that upon performing thermo-mechanical cycling treatment of the dental restoration on human teeth, the
adhesive with the methacrylate-modified chitosan, in variance with the control adhesive, did not show any decrease in the bond
strength (28.4 ± 8.8 MPa). The modified chitosan is proposed as a component of the “etch-and-rinse” adhesive system to
efficiently improve the durability of dental restorations.