Surface Characterization, Antimicrobial Activity of Nonthermal Atmospheric-Pressure Plasma Jet on Polyvinyl Siloxane...

Background and Objectives The antimicrobial efficacy of a nonthermal atmospheric-pressure plasma jet (NAPPJ) on dental impression materials was investigated. Materials and Methods Type 3 polyvinyl siloxane was used as the impression material, and air and nitrogen NAPPJ were applied. The antibacterial effect of the NAPPJ was measured using the number of colony-forming units (CFUs) and scanning electron microscopy (SEM) images of Streptococcus mutans. Surface chemical characteristics of the impression material were examined using X-ray photoelectron spectroscopy (XPS) and contact angle measurement. Additionally, physical properties were analyzed through surface roughness measurement, detail reproduction, and strain-in-compression test. Results Compared with the control group, the plasma treatment group showed ruptured bacteria membranes, destroyed bacteria structures, a significant reduction in the number of CFUs, and a significantly reduced contact angle. Further, XPS analysis showed that their surface was significantly richer in hydroxyl groups. The surface roughness, detail reproduction, and strain-in-compression results indicated no significant differences between the plasma treatment and control groups. NAPPJ treatment could remove bacteria from polyvinyl siloxane dental impression materials without changing the surface's physical properties. Conclusion Therefore, it is considered a promising method for disinfection.