The aim was to evaluate the physical properties and anti-bacterial activity of resin cement containing ursolic acid (UA) and determine the optimal concentration of UA. Five types of experimental resin cement were prepared according to UA concentration (0, 0.1, 0.5, 1.0, and 2.0 wt%). Flexural strength, film thickness and in vitro cytotoxicity were measured to confirm whether the resin was appropriate under International Organization for Standardization (ISO) criteria. Fifty extracted human molars were prepared, and indirect resin inlays were cemented with experimental resins. Acid-resistant nail varnish was applied, except for the 2-mm area around the restoration. Artificial caries were induced for 6 days through Streptococcus (S.) mutans (ATCC25175). Quantitative light-induced fluorescence (QLF) was used to evaluate the caries progression. One-way analysis of variance (ANOVA) followed by the Dunnett correction were used to statistically analyze the data. In all groups, the physical property of flexural strength, film thickness, and cytotoxicity were satisfied for ISO criteria (p > 0.05). On ∆F (-%) and ∆Q (-%⋅Px) values as QLF parameters, there was a tendency of being lower in groups of resin cement containing higher concentration of UA. Resin cement containing UA of greater than or equal to 0.5% significantly inhibited caries in the area around restoration (p < 0.05). There was no difference between the groups containing UA of greater than or equal to 0.5%. Resin cement containing 0.5% or more UA showed anti-carious effect in the limited range of 2% and satisfied the ISO criteria for flexural strength, film thickness and cytotoxicity.
Keywords: Anticariogenic resin cement; Cytotoxicity; Film thickness; Flexural strength; Ursolic acid.