Silver core-shells particles as antibacterial filler for adhesive resins

Abstract

Objectives

To evaluate the addition of Ag@SiO₂ on the physicochemical and biological properties of an experimental adhesive resin.

Materials and methods

Ag@SiO₂ particles were synthesized using a modified Stöber sol-gel process and added to a resin adhesive containing Bis-GMA (66.6 wt%) and HEMA (33.3 wt%). The particles were incorporated into the adhesive resin at 1 wt% (G_1%), 2.5 wt% (G_2.5 %), and 5 wt% (G_5%) for the experimental groups. The unfilled adhesive base was used as a control (G_0%). The adhesives were characterized by the degree of conversion, softening in solvent, ultimate tensile strength, microtensile bond strength, cytotoxicity, and antibacterial activity.

Results

The degree of conversion decreased for the 5 wt% Ag@SiO₂ containing group when compared to the control (G_0%) and 1 wt% (G_1%) groups (p < 0.05). A decrease in Knoop microhardness was observed for all groups after immersion in solvent (p < 0.05). Ultimate tensile strength was not affected by particle addition (p > 0.05). The addition of Ag@SiO₂ decreased bond strength (p < 0,05). All groups achieved over 90 % cell viability for SRB assay. Antimicrobial effects against S. mutans bacteria were observed, both in planktonic and biofilm environments (p < 0.05).

Conclusion

The adhesives added with 2.5 wt% Ag@SIO₂ presented an adequate polymeric structure even though bond strength was affected. The addition of Ag@SiO₂ in adhesives promoted antibacterial activity without cytotoxic side effects.