Research progress on <i>Ligilactobacillus salivarius</i> in the prevention and treatment of oral diseases

The oral cavity harbors a diverse population of microorganisms, making it one of the most heavily colonized sites in the human body. Maintaining a balanced microecology is crucial for oral health. <i>Ligilactobacillus salivarius</i> as a species of <i>Ligilactobacillus</i>, has good oral colonization ability and potential to improve oral microecology for disease prevention and control. Currently, the application and mechanism of <i>Ligilactobacillus salivarius</i> in oral diseases include several aspects. First, by directly inhibiting the growth of <i>Streptococcus mutans</i> and downregulating the expression of its cariogenic virulence factor, gtfs, the aim is to reduce the number of adherent <i>Streptococcus mutans</i> on the tooth surface, thereby preventing dental caries. Second, reducing the number of keystone taxa in periodontitis, and the virulence factors of <i>Aggregatibacter actinomycetemcomitans</i>, including CdtB and LtxA, can alleviate local stimulation in patients with periodontitis. Additionally, directly inhibiting macrophage MAPK and NF-κB pathway activation suppresses osteoclastogenesis and reduces periodontal bone absorption. In mucosal inflammation, <i>Ligilactobacillus salivarius</i> competes with <i>Candida albicans</i>, inhibits the formation of pathogenic hyphae or germ tubes, and prevents monilial stomatitis. <i>Ligilactobacillus salivarius</i> can also reduce the amount of <i>Staphylococcus aureus</i> and mitigate the activation of the macrophage TLR/PI3K/Akt/mTOR and TLR/PI3K/Akt/IκB/NF-κB pathways induced by <i>S. aureus</i> infections, thus alleviating inflammation in the oral and pharyngeal regions. <i>In vitro</i> studies on oral tumors have revealed that <i>Ligilactobacillus salivarius</i> can downregulate the expression of cancer cell Akt/Cyclin D1, induce direct apoptosis of tumor cells, reduce COX-2 expression, and improve the tumor immune-suppressive microenvironment. Previous studies have revealed considerable variability in <i>Ligilactobacillus salivarius</i>, necessitating more detailed research to clarify its clinical effects, safety, and mechanisms. Despite the emergence of novel microbiological research techniques, their application to <i>Ligilactobacillus salivarius</i> remains relatively limited. One crucial direction for future research is to better utilize these methods to investigate the effects of <i>Ligilactobacillus salivarius</i> on oral diseases. Considering these factors, this study provides a comprehensive review of existing research studies on <i>Ligilactobacillus salivarius</i> in the fields of oral medicine and dentistry, with the aim to serve as a reference and guide for future studies.