Abstract Chlorhexidine (CHX) mouthwash is widely used clinically to remove the established Streptococcus mutans biofilm and prevent caries. However, the long-term use with high concentration of CHX leads to the staining of tooth and mucous membrane. In this study, d -leucine ( d -leu) was used as an antimicrobial enhancer for CHX against mature S. mutans biofilm. The biocidal efficacy was evaluated by means of quantitative antibacterial test and biofilm observation. The results indicated that 100 ppm d -leu alone was ineffective to remove the S. mutans biofilm. Moreover, the biocidal effect of 1 ppm CHX was also inadequate to eradicate the biofilm. When 100 ppm d -leu was mixed with 1 ppm CHX, most of the mature S. mutans biofilm on 316L stainless steel coupon surfaces were successfully removed, and the removal efficacy was equivalent to that of 10 ppm CHX alone. The results confirmed that d -leu significantly enhanced the antibiofilm effect of CHX, dissembling the tenacious biofilm into easily killed planktonic counterparts. d -leu represents a novel strategy to reduce the dosage of CHX with a guaranteed effect for caries prevention.

中文翻译：

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d-亮氨酸增强氯己定对致龋变形链球菌生物膜的抗生物膜活性

摘要 洗必泰（CHX）漱口水在临床上广泛用于去除已形成的变形链球菌生物膜，预防龋齿。然而，长期使用高浓度的 CHX 会导致牙齿和粘膜染色。在这项研究中，d-亮氨酸 (d-leu) 被用作 CHX 对成熟变形链球菌生物膜的抗菌增强剂。通过定量抗菌试验和生物膜观察来评价杀菌效果。结果表明，单独的 100 ppm d-leu 不能有效去除变形链球菌生物膜。此外，1 ppm CHX 的杀生物作用也不足以根除生物膜。当 100 ppm d-leu 与 1 ppm CHX 混合时，316L 不锈钢试样表面上的大部分成熟变形链球菌生物膜被成功去除，去除效果相当于单独使用 10 ppm CHX 时的效果。结果证实，d-leu 显着增强了 CHX 的抗生物膜作用，将坚韧的生物膜分解成容易杀死的浮游生物膜。d -leu 代表了一种减少 CHX 剂量并保证防龋效果的新策略。