Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, Rua Humaitá, 1680, Araraquara, Sao Paulo, 14801-903, Brazil.
BMC Complement Altern Med. 2018 Feb 14;18(1):61. doi: 10.1186/s12906-018-2132-x.
Dental caries is considered a multifactorial disease, in which microorganisms play an important role. The diet is decisive in the biofilm formation because it provides the necessary resources for cellular growth and exopolysaccharides synthesis. Exopolysaccharides are the main components of the extracellular matrix (ECM). The ECM provides a 3D structure, support for the microorganisms and form diffusion-limited environments (acidic niches) that cause demineralization of the dental enamel. Streptococcus mutans is the main producer of exopolysaccharides. Candida albicans is detected together with S. mutans in biofilms associated with severe caries lesions. Thus, this study aimed to determine the effect of tt-farnesol and myricetin topical treatments on cariogenic biofilms formed by Streptococcus mutans and Candida albicans.
In vitro dual-species biofilms were grown on saliva-coated hydroxyapatite discs, using tryptone-yeast extract broth with 1% sucrose (37 °C, 5% CO). Twice-daily topical treatments were performed with: vehicle (ethanol 15%, negative control), 2 mM myricetin, 4 mM tt-farnesol, myricetin + tt-farnesol, myricetin + tt-farnesol + fluoride (250 ppm), fluoride, and chlorhexidine digluconate (0.12%; positive control). After 67 h, biofilms were evaluated to determine biofilm biomass, microbial population, and water-soluble and -insoluble exopolysaccharides in the ECM.
Only the positive control yielded a reduced quantity of biomass and microbial population, while tt-farnesol treatment was the least efficient in reducing C. albicans population. The combination therapy myricetin + farnesol + fluoride significantly reduced water-soluble exopolysaccharides in the ECM (vs. negative control; p < 0.05; ANOVA one-way, followed by Tukey's test), similarly to the positive control.
Therefore, the combination therapy negatively influenced an important virulence trait of cariogenic biofilms. However, the concentrations of both myricetin and tt-farnesol should be increased to produce a more pronounced effect to control these biofilms.
龋齿被认为是一种多因素疾病，其中微生物起着重要作用。饮食在生物膜形成中起决定性作用，因为它为细胞生长和胞外多糖合成提供了必要的资源。胞外多糖是细胞外基质（ECM）的主要成分。ECM 提供 3D 结构，为微生物提供支撑，并形成扩散受限的环境（酸性龛），导致牙釉质脱矿。变形链球菌是胞外多糖的主要生产者。白色念珠菌与变形链球菌一起存在于与严重龋齿病变相关的生物膜中。因此，本研究旨在确定 tt-法呢醇和杨梅素局部治疗对变形链球菌和白色念珠菌形成的致龋生物膜的影响。
在唾液包被的羟基磷灰石盘上，使用含有 1%蔗糖的胰蛋白胨-酵母提取物肉汤（37°C，5%CO）体外共培养双物种生物膜。每天两次进行局部治疗：载体（乙醇 15%，阴性对照）、2mM 杨梅素、4mM tt-法呢醇、杨梅素+tt-法呢醇、杨梅素+tt-法呢醇+氟化物（250ppm）、氟化物和葡萄糖酸氯己定（0.12%；阳性对照）。67 小时后，评估生物膜以确定生物膜生物量、微生物种群以及 ECM 中的水溶性和不溶性胞外多糖。
只有阳性对照降低了生物量和微生物种群的数量，而 tt-法呢醇处理在降低白色念珠菌种群方面效果最差。杨梅素+法呢醇+氟化物联合治疗显著降低 ECM 中的水溶性胞外多糖（与阴性对照相比；p<0.05；单因素方差分析，随后进行 Tukey 检验），与阳性对照相似。
因此，联合治疗对致龋生物膜的一个重要毒力特性产生了负面影响。然而，应该增加杨梅素和 tt-法呢醇的浓度，以产生更明显的效果来控制这些生物膜。
