Microstructural characterization of acrylic resins composed of semiconductors to promote antimicrobial activity

The incorporation of semiconductors in acrylic resins can promote antimicrobial activity, reduce infections and oral diseases, maintain physical-mechanical performance to ensure longevity of the prosthetic device. This study aims to compare the antimicrobial effect of the semiconductor &beta;-AgVO3 in self-cured (AP) and heat-cured (TP) resin previously evaluated at different concentrations with the semiconductor &alpha;-Ag2WO4 as an alternative of a new material with antimicrobial potential. For this, the minimum inhibitory concentration (MIC) of &beta;-AgVO3 and &alpha;-Ag2WO4 was determined against C. albicans, S. mutans, S. aureus, and P. aeruginosa. Antimicrobial properties were investigated by Tetrazolium Salt Reduction Test-XTT, colony forming units (CFU), and biofilm analysis by laser confocal microscopy (LCM). The physical-mechanical properties were evaluated by testing hardness, surface roughness, flexural strength, impact strength, scanning electron microscopy (SEM), energy dispersive elemental analysis (EDS) and Fourier transform infrared spectroscopy (FTIR). For data analysis, qualitative analysis of CIM, LCM, SEM and EDS were performed. Two-way ANOVA followed by Bonferroni post-test with (P >0.05) for CFU, One-way ANOVA followed by Tukey\'s post-test with (P <0.05) for flexural strength, roughness, hardness, and impact strength, and Kruskal-Wallis and Dunn\'s post-test (P >0.05) for XTT. The &alpha;-Ag2WO4 showed better MIC in mg/mL against C. albicans, S. aureus, and S. mutans compared to &beta;-AgVO3. The addition of &alpha;-Ag2WO4 did not obtain antimicrobial efficacy and the 3% concentration of &beta;-AgVO3 was effective for the reduction of C. albicans, S. mutans, and P. aeruginosa. For hardness, AP resin showed no significant change with the incorporation of the semiconductors and was reduced in the 1% &alpha;-Ag2WO4 TP group. The increase in roughness in AP was proportional to the addition of both semiconductors and for TP only the 3% groups showed an increase. The addition of 3% of both semiconductors reduced the flexural strength of the TP resin. The impact strength was reduced in all groups with the incorporation of the TP resin. In SEM the presence of pores and irregularities was observed and in EDS the chemical components of the added semiconductors. The FTIR spectrum was not altered with the incorporation of AP and TP resins. It can be inferred that &beta;-AgVO3 and &alpha;-Ag2WO4 presented bactericidal and fungicidal MIC, the incorporation of 3% &beta;-AgVO3 promoted antimicrobial activity, and both semiconductors altered the physical-mechanical properties. (AU)