β-glycyrrhetinic acid exerts an exfoliating effect on marginal gingivitis-inducing plaque biofilms

β-glycyrrhetinic acid (BGA) possesses antibacterial effects against human supragingival plaque bacteria and inhibit biofilm formation. This study analyzed and compared the effects of BGA on preformed supragingival plaque biofilms with those of cetylpyridinium chloride (CPC). All the experiments were performed using biofilms formed by incubating supragingival plaque bacteria for 24 h. First, we analyzed the number of viable and dead bacteria in the biofilms following BGA and CPC application. The number of viable bacteria was significantly reduced by BGA treatment than by the control. However, the viable/dead bacterial ratios did not significantly vary. Conversely, the turbidity in the supernatants (optical density at 600 nm [OD ₆₀₀ ]) was 0.237 ± 0.003, 0.136 ± 0.002, and 0.096 ± 0.002 for the BGA, CPC, and control groups, respectively, indicating superior ability of BGA in biofilm exfoliation. Finally, we evaluated the strength of the biofilms based on the physical impact of BGA or CPC treatment. The biofilm amount ratio before and after sonication was significantly reduced by BGA and CPC than by the control. Furthermore, CPC demonstrated significantly greater reduction in biofilm formation than BGA following sonication. BGA demonstrated excellent bactericidal and exfoliating effects on human supragingival biofilms. These effects are presumably attributed to a mechanism different from that of CPC.