Salivary lysozyme, lactoferrin and peroxidases: antibacterial effects on cariogenic bacteria and clinical applications in preventive dentistry.

Many antimicrobial agents in human saliva are known to have bacteriostatic or bactericidal effects on cariogenic bacteria, in particular against Streptococcus mutans. Studies have usually been conducted with purified agents (proteins) in vitro. Very little proof exists to show that they also affect oral cariogenic flora in vivo. Recent studies have shown that some salivary systems can act synergistically against Streptococcus mutans. Such synergistic antibacterial activity is likely to exist in the human mouth. Attempts to enhance the anticariogenic properties of saliva have been made by adding antimicrobial proteins such as peroxidase, lactoferrin and lysozyme to oral health products. Although clinical evidence is still limited, the idea of using such antimicrobial agents--"natural antibiotics"--rather than synthetic agents against cariogenic bacteria seems promising.