No abstract

Introduction: Despite of the recent advances in the adhesive dentistry, high possibility of microbial biofilm development at the resin restoration surfaces may lead to marginal gaps and recurrent caries. Degree of conversion of the dental adhesive represents a relative assessment to its quality, and a direct correlation with its mechanical behavior. This in vitro study was carried out to investigate the minimum inhibitory concentration of antimicrobial silver nanoparticles incorporated in two forms into the self-etch adhesive system and the effect of their incorporation on the degree of conversion of the self-etch adhesive. Methods: Minimum Inhibitory Concentration of the self-etch adhesive system incorporated with nanosilver powder and solution against Streptococcus mutans was tested using an agar diffusion test. The effect of nanosilver incorporation (powder and ethanol-based solution) in the self-etch adhesive system on its degree of conversion was assessed using Attenuated Total Reflectance/ Fourier Transform Infra-Red spectrometer (ATR/ FTIR). Results: The results showed that silver nanoparticles incorporation (powder or ethanol based at 12.5 µg/ml concentration) significantly increased the antibacterial efficacy of the self-etch adhesive against Streptococcus mutans (P< 0.05). Nanosilver powder possessed higher significant antibacterial effect when compared to silver ethanol based solution (P< 0.05). Degree of conversion of self-etch adhesive containing nanosilver powder showed non-significant difference from the control group (p > 0.05). In contrast, self-etch adhesive with nanosilver solution recorded significantly lower values when compared to the control or nanosilver powder group (P< 0.05). Conclusion:  The antibacterial efficacy of the adhesive system can be greatly potentiated with the addition of silver nanoparticles (12µg/mL concentration) especially the nanosilver powder. Incorporation of the antibacterial nanosilver powder in the adhesive system didn’t compromise the degree of conversion of the adhesive resin.