Abstract
BACKGROUND: This study aimed to evaluate the effect of incorporating different concentrations of nanochitosan (NCH) into Fuji Plus resin-modified glass ionomer luting cement (RMGIC; GC Corporation, Tokyo, Japan) on shear bond strength, film thickness, solubility, water sorption, and antibacterial activity. METHODS: The liquid component of fuji Plus RMGIC was modified by incorporating NCH at 0% (control), 5%, 10%, and 20% (v/v). A total of ten specimens were prepared per group for each test. Shear bond strength (SBS) was assessed using human mid-coronal dentine after thermocycling. Film thickness was measured in accordance with ISO 4049 and ANSI/ADA guidelines. Water sorption and solubility were assessed after 28 days in artificial saliva. Antibacterial activity against Streptococcus mutans was determined via the agar disc diffusion method. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test (α = 0.05). RESULTS: NCH incorporation significantly influenced the tested properties of RMGIC. Bond strength remained unaffected at 5% and 10% but significantly decreased at 20% (p ≤ 0.05). Film thickness increased only at 20% (p ≤ 0.05). Water sorption showed a concentration-dependent increase, while solubility significantly decreased with increasing NCH content (p < 0.0001). Antibacterial activity against Streptococcus mutans improved significantly with higher NCH concentrations, as evidenced by larger inhibition zones in all modified groups compared to the control (p < 0.0001). CONCLUSIONS: Incorporation of NCH into RMGIC enhanced its antibacterial activity and reduced solubility without compromising bond strength or film thickness up to 10%. However, a 20% addition adversely affected the mechanical and handling properties.