Propriedades físico-químicas e antimicrobianas de uma resina ortodôntica modificada pela incorporação de nanopartículas de prata com fosfato de cálcio

Abstract

The objective of this study is to assess physicochemical properties, enamel strength and antibacterial effect of an orthodontic resin (OR) incorporated with silver nanoparticles (AgNPs) with or without calcium phosphate (CaP). Methods: ORs were prepared with 0, 1 or 5wt% of AgNP and 0, 1 or 5wt% AgNP and CaP. Physicochemical properties were evaluated in terms of degree of conversion (DC), water sorption (WS) and solubility (SO), three point bending (flexural strength, FS and modulus, E) and surface roughness (Ra) and Knoop microhardness (KHN). Enamel adhesion was evaluated by shear bond strength test (SBS). Resin’s antimicrobial activity against Streptococcus mutans was measured by counting colony-forming units. The data was statistically analyzed by one-way ANOVA and Tukey’s test (p<0.05). Results showed that the DC, FS, KHN, SBS and antimicrobial tests showed no statistical difference between control and experimental groups. WS value decrease in OR 1wt% AgNP and SO value also decrease in OR 5wt% AgNP. FS achieve higher result in OR 5wt% AgNP. OR 1wt% and 5wt% AgNP and 5wt% AgNP with CaP attained statistically lower roughness than OR. Significance: The incorporation of AgNP in OR alters some physical-chemical properties, but does not interfere in its adhesion to the enamel. The use of CaP associated with AgNP might attain remineralization when undergoing acid challenges. Its antimicrobial potential has not been verified, but more studies are necessary to confirm this fact.