Evaluation of Antimicrobial Activity and Physical Properties of Vinyl Siloxane Ether Impression Material Modified with Zinc Oxide and Chitosan Nanoparticles: An In-vitro Study

Introduction: The antimicrobial activity and physical properties of Vinyl Siloxane Ether (VSE) impression material, such as dimensional stability, flow, and setting time, play a crucial role in the success of fixed prosthodontics. During impression making, the impression material is exposed to infected blood and saliva, which are potential sources of cross-contamination. Cross-contamination can be decreased or minimised when antimicrobial agents are added to the impression material. The efficacy of nanoparticles like silver, titanium, zinc oxide, and chitosan as antimicrobial agents is continuously researched in dentistry. These particles have the benefit of being small and possessing effective antibacterial characteristics due to their vast surface area, which creates an effective interaction with microbes. Aim: To evaluate and compare the antimicrobial activity and physical properties of VSE impression material incorporated with various concentrations (0.0, 1.0, and 2.5 wt.%) of zinc oxide and chitosan nanoparticles. Materials and Methods: This is an in-vitro study conducted in the Department of Prosthodontics at KIMS Dental College and Hospital, Amalapuram, Andhra Pradesh, India. Ethical Review Board for clinical trials (Material protocol no. 020/ KIMS DENTAL/2022). The study was conducted in the month of June and July of 2022 year. A total of 252 samples were fabricated with VSE impression material and divided into two groups for antimicrobial activity ( Staphylococcus aureus, , Pseudomonas aeruginosa, , and the fungus Candida albicans) ) and physical properties (dimensional stability, flow, setting time) with 126 samples in each group, respectively. The sample size was estimated using G Power One software with a power of 91% and an alpha error of 5%. Antimicrobial activity was determined using the disk diffusion method, dimensional stability was determined with a stereomicroscope, setting time with a Gillmore apparatus, and flow with a vernier caliper. Data were subjected to one-way Analysis of Variance (ANOVA) (p-value <0.05), T tests, and Tukey post-hoc tests, respectively. A p-value of <= 0.05 was considered statistically significant. Results: Significant changes were noted against Staphylococcus aureus bacteria when VSE was incorporated with 2.5% zinc oxide nanoparticles (p-value=0.010). The highest setting time was found for 2.5% chitosan, and the lowest setting time was for 2.5% zinc oxide (p-value <0.001). Decreased flow was observed with 2.5% chitosan, whereas increased flow was observed with 1% and 2.5% of zinc oxide nanoparticles (p-value=0.016). Enhanced dimensional stability was seen when the impression material was incorporated with 1% and 2.5% of ZnO nanoparticles (p-value <0.001). Conclusion: Based on this in-vitro study, zinc oxide and chitosan nanoparticles can be incorporated into VSE impression material as antimicrobial agents without adversely affecting their properties.