Anti-cariogenic effect of experimental resin cement containing ursolic acid using dental microcosm biofilm

This study aimed to assess the anticariogenic effects of resin cement containing varying ursolic acid (UA) concentrations and to determine the optimal UA concentrations in the microcosm biofilm model.

Experimental resin cements with UA concentrations of 0, 0.1, 0.5, 1.0, and 2.0 wt% were prepared. Class I cavities were prepared on 50 extracted human molars and restored with composite inlays and experimental resin cements. Tooth samples were subjected to artificial caries induction for 10 days in a microcosm biofilm model using human saliva as an inoculum, and then mineral changes were evaluated using quantitative light-induced fluorescence (ΔF and ΔQ) and micro-computed tomography (CT). The bacterial composition of the human saliva was analyzed by 16 s RNA microbiome profiling. One-way analysis of variance with Tukey and Duncan post-hoc tests was employed for statistical analysis (p < 0.05).

As the UA concentration increased, resin cement decreased ΔF and ΔQ before and after caries induction but showed a significant difference only in ΔQ at UA concentration ≥ 1.0 % (p < 0.05). The gray value analysis result of micro CT also showed a significant difference at UA concentration ≥ 1.0 % (p < 0.05). In the human saliva analysis, bacterial composition remained within normal oral microbiota ranges.

Resin cements containing at least 1.0 % of UA exhibited an anticariogenic effect on dental microcosm biofilms.

To reduce the failure of restorations, it is essential to prevent the occurrence of secondary caries. The application of UA in resin cement can be utilized to prevent the formation of secondary caries due to the anticariogenic effect of UA.