You can’t discuss healthy teeth without addressing saliva, the extracellular fluid essential to oral health. Saliva delivers nutrients to teeth and acts as a baseline defense against harmful bacteria, playing a critical role in cavity prevention. Maintaining oral pH within the range of 6.8 to 7.8 is a key function of saliva, ensuring a stable environment for oral health. With the oral cavity as a primary entry point for pathogens and host to over 700 microbial species, the protective functions of saliva are indispensable.
Saliva performs multiple essential functions, including lubrication, pH buffering, and tooth mineralization. Its composition and flow are influenced by factors such as circadian rhythm, diet, age, medications, and disease. A key feature of saliva is the mucosal pellicle, a hydrogel-like layer formed by heavily glycosylated mucin proteins. This layer traps water, creating a viscoelastic shield that coats the soft tissues of the mouth, providing hydration and defense against mechanical and microbial challenges.
Beyond protection, saliva facilitates wound healing and aids in the dissolution and diffusion of food particles within the oral cavity. It continuously lubricates wounds, reducing tissue dehydration and promoting healing through cytokines, chemokines, and growth factors. Additionally, the most abundant salivary protein, alpha-amylase, though minimally involved in starch digestion, plays a significant role in dissolving and removing food debris from teeth, further supporting oral cleanliness.
Human salivary glands produce 0.5 to 1.5 liters of saliva daily, with major contributions from the parotid and submandibular glands. This complex biofluid, made up of 99% water and 1% electrolytes, enzymes, and other molecules, serves to moisten, protect, and clean oral tissues. Saliva’s intricate composition includes ions such as calcium and bicarbonate, alongside proteins like mucins and immunoglobulin A (IgA), underscoring its role in maintaining oral health and supporting functions like speaking and swallowing.
Uchida, H., & Ovitt, C. E. (2022). Novel impacts of saliva with regard to oral health. The Journal of prosthetic dentistry, 127(3), 383–391. https://doi.org/10.1016/j.prosdent.2021.05.009