LL-37 is a natural antimicrobial protein made by immune cells and mouth lining cells. In gum disease (periodontitis) its levels go up in the fluid around the teeth, and it seems to help fight bacteria, control inflammation, and aid tissue repair. Researchers think it could become a useful marker for gum disease or a target for new treatments, but no concrete home‑use protocols exist yet.

LL-37 is the sole member of the cathelicidin family of antimicrobial peptides in humans, primarily produced by phagocytic leukocytes and epithelial cells, mediating a wide range of biological responses. Discovered in human neutrophils, LL-37 is known for its broad-spectrum antimicrobial activity and immunomodulatory functions. In periodontitis, LL-37 is mainly expressed in gingival epithelium, gingival sulcus fluid, and saliva. Emerging evidence from several studies suggests that LL-37 is significant in the development of periodontitis, exhibiting antimicrobial, immunomodulatory, and tissue regenerative effects. Several studies have quantified the levels of LL-37 in gingival crevicular fluid (GCF), revealing elevated levels in patients with periodontitis compared to healthy controls. This review summarizes the expression and roles of LL-37 in periodontitis, providing new perspectives and insights into its pathogenesis and potential treatments. Additionally, this review aims to identify potential areas for future research, including therapeutic applications and biomarker development.