Research progress on quorum sensing in the caries-causing effects of <i>Streptococcus mutans</i> and <i>Candida albicans</i>

Dental caries is a major disease that seriously endangers human oral health. Dental plaque biofilm composed of many microorganisms is the primary factor of dental caries. Inhibiting biofilm formation has become the focus of research on the prevention and treatment of dental caries. <i>Streptococcus mutans</i> and <i>Candida albicans</i>, as common pathogenic bacteria in the oral cavity, are closely related to the occurrence of dental caries. The interaction between the two can lead to the rapid onset of dental caries. In recent years, many studies have found that <i>Candida albicans</i> promotes the occurrence of caries by interacting with <i>Streptococcus mutans</i>, including physical adhesion, promoting the production of exopolysaccharides (EPS), reducing the pH of the microecological environment, forming a highly cariogenic acidic environment, and secreting quorum sensing molecules to trigger quorum sensing. As a communication mechanism between microorganisms, the quorum sensing system mainly includes three main types: autoinducing peptide (AIP) system, autoinducer-2 (AI-2) system, and Acyl-homoserine lactone (AHL) system. At present, quorum sensing has been shown to promote the occurrence of diseases by activating the expression of microbial pathogenicity-related genes, promoting EPS synthesis and biofilm formation. The CSP-ComDE and ComRS quorum sensing systems of <i>Streptococcus mutans</i> allow the bacteria to survive and cause disease in extreme environments that are unfavorable for survival, while the quorum sensing system of <i>Candida albicans</i> is mainly mediated by farnesol, which has a negative regulatory effect on the yeast-hyphae transformation of <i>Candida albicans</i>. Studying the quorum sensing phenomenon of the two bacteria is helpful to understand the etiology of caries. In recent years, many studies have reported the use of quorum sensing inhibitors in anti-microbial applications. The study of microbial quorum sensing systems and inhibitors will help the prevention and treatment of caries. With the increasing interest in biofilm-related research, and a new method for in-depth study of the biofilm formation process and quorum sensing behavior using microfluidic and chip laboratory technology is proposed. The author summarizes the cariogenic effects, the quorum sensing system and quorum sensing inhibitors of <i>Streptococcus mutans</i> and <i>Candida albicans</i>.