Saliva

Saliva is a complex biological fluid composed of both mucous and serous secretions, which are pale yellow, transparent, and physiologically benign. It is primarily produced by the salivary glands, whose anatomical structure and functional mechanisms play a crucial role in maintaining oral homeostasis. Beyond its role in facilitating oral lubrication, saliva is an essential component in the prevention and modulation of oral diseases, particularly dental caries.

Saliva contains a diverse array of biochemical constituents, including calcium, phosphate, fluoride, proteins, antibacterial agents, lipids, and buffering compounds, each of which contributes to its protective and reparative functions. One of its primary mechanisms in caries prevention is its buffering capacity, which helps neutralize acids produced by bacterial metabolism. This acid neutralization is critical in mitigating enamel demineralization. Additionally, saliva serves as a reservoir of calcium and phosphate, essential ions that not only slow the dissolution of enamel minerals but also facilitate remineralization processes. Notably, fluoride efficacy in enhancing enamel remineralization is contingent upon the availability of calcium and phosphate within the oral environment.

Furthermore, saliva exhibits a robust antimicrobial function, containing multiple antibacterial agents that inhibit bacterial proliferation and modulate the oral microbiome. In conditions where salivary flow is significantly reduced or compromised, such as in xerostomia, the absence of these protective factors results in a heightened susceptibility to dental caries (10-20 times as great as a normal individual), even in the presence of fluoride treatment. This underscores the indispensable role of saliva in maintaining oral health and preventing the pathological consequences of bacterial activity.¹¹