Impact of Antimicrobial Peptides in Saliva on Oral Biofilm Regulation and Caries Susceptibility

Background: Dental caries is one of the most common chronic oral diseases, which is related to biofilm activity and host defense. The current study aimed at investigating the connection between salivary AMPs, oral biofilm burden, and caries vulnerability. Methods: This analytical cross-sectional comparative study (March 2023 to August 2023) included 120 participants aged 18-35 years were divided into two groups, caries-free (Decayed, Missing, and Filled Teeth (DMFT) = 0) and high-caries (DMFT =5). Quantification of cathelicidin (LL -37), Human Beta-Defensin-2 (hBD -2)s and histatin -5 in unstimulated saliva samples was performed through Enzyme-Linked Immunosorbent Assay (ELISA). Automated Commercial Robotic Quantitative polymrease chain reaction (qPCR) of oral biofilm extracts on total bacterial load and enumeration of Streptococcus mutans was done. Data were analyzed in SPSS v26.0 with the p-value<0.05. Results: The mean salivary concentrations of LL-37 ( p < 0.001), hBD-2 ( p < 0.001) and histatin-5 ( p < 0.001) were significantly low in participants in the high-caries group. Strong inverse correlations were observed between the AMP concentrations and the bacterial load and DMFT scores: LL-37 ( r =-0.61, p <0.001), hBD-2 ( r =-0.53, p <0.001), and histatin-5 ( r =-0.64, p <0.001). These results indicate that lower levels of AMP accompany greater accumulation of microbial and caries severity. Conclusion: Reduction in salivary levels of AMP is strongly linked with an increased occurrence of oral biofilm and caries vulnerability. Periodic assessment of AMP levels may help to detect people at risk and shape the preventive oral health interventions.