Human saliva, though at times being given less attention, performs a crucial task in battling the injurious pathogens in the mouth and in thwarting the tooth decay. Pathogens are any virus, microorganisms, or other substances that cause disease. A primary factor of the first-line oral defense mechanism of the saliva is the alleged secreted antimicrobial peptides also known as AMPs. Peptides is a compound of two or more amino acids in which a carboxyl group of one is united with an amino group of another, with the elimination of a molecule of water, thus forming a peptide bond such as a substituted amide.
Antimicrobial peptides also known as host defense peptides are evolutionarily preserved factor of the inherent immune response and are seen among every class of life. These peptides are potent, wide spectrum antibiotics that display possibility as new therapeutic agents. Antimicrobial peptides have been revealed to destroy gram-negative and gram-positive bacteria involving strains that are resistant to traditional antibiotics, mycobacteria, enclosed viruses, fungi and even altered or cancerous cells. Nothing like the greater part of traditional antibiotics it seems as though antimicrobial peptides may also have the capability to improve immunity through acting as immunomodulators.

Research recommends two particular types of antimicrobial peptides known as defensins and cathelicidins that have wide antimicrobial influences against both gram-negative and gram-positive oral bacteria. The information that is still not clear is whether alterations in the levels of these secreted peptides among children correlate with tooth decay risk. Defensins is a class of basic antibiotic peptides that are found in neutrophils, which apparently kill bacteria by causing membrane damage. Cathelicidins are characterized by a highly conserved region known as the cathelin domain and a highly variable cathelicidin peptide domain. Cathelicidin peptides have been segregated from many different species of mammals. They were originally discovered in neutrophils but have since been observed in many other cells such as in macrophages activated by bacteria, viruses, fungi or some hormones. They share primary sequence homology with the cathepsin family of cysteine proteinase inhibitors, although amino acid residues thought to significant in such protease inhibition are commonly lacking.

Gram negative refers to the inability of a bacterium to resist decolorization with alcohol after being treated with Gram crystal violet. However, following decolorization, these bacteria can be readily counterstained with safranin, imparting a pink or red color to the bacterium when viewed by light microscopy. Gram positive refers to the ability of a bacterium to resist decolorization with alcohol after being treated with Gram crystal violet stain, imparting a violet color to the bacterium when viewed by light microscopy.
In one of the issues of Antimicrobial Agents and Chemotherapy, a team of grantees of the National Institute of Dental and Craniofacial Research together with their collaborators discovered expansive differences in antimicrobial peptides levels among children and noticed that salivary levels of a peptide known as HNP1-3 can possibly be a factor to caries vulnerability and could be a novel and helpful measure of risk for caries in children.