Saliva- a key component in maintaining a balanced oral microbiome, Study finds

The study is published in the Journal of Dentistry.

Saliva is a key component in maintaining a balanced oral microbiome and it exerts a large variety of functions that help to promote oral health. The importance of the complex interaction between host, saliva and the oral microbiota becomes evident when the salivary flow is reduced, and the composition is altered, leading to dysbiosis and the risk of associated oral diseases such as dental caries, gingivitis and oral fungal infections.

Salivary constituents provide an important nutritional source for several microorganisms, and the complex interaction of many salivary inorganic and organic constituents is essential for the maintenance of a balanced and beneficial microbiota and for symbiosis.

Hence, Anne Marie Lynge Pedersen and associates from the Oral Medicine and Oral Pathology, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark conducted this study to provide an update on the current understanding of how saliva and its various constituents directly and indirectly affect oral bacteria and thereby play a role in the modulation and maintenance of a healthy oral microbiota and also the associations with symbiosis and dysbiosis.

The authors laid out the following key facts-

1. Saliva plays an essential role in shaping and maintaining the ecological equilibrium of the resident oral microbiota.
2. Saliva contributes to the formation of the salivary pellicle, which covers the oral hard and soft tissues, and thereby determines the initial adhesion and colonisation of microorganisms.
3. Saliva facilitates clearance of dietary carbohydrates and microorganisms from the oral cavity, but also supplies bacteria with nutrients through enzymatic breakdown of dietary starch and proteins and salivary glycoproteins.
4. In addition, saliva comprises proteins such as mucins, which block the adherence of certain microorganisms to oral surfaces through binding and aggregating mechanisms.
5. Saliva also provides antimicrobial activity through numerous proteins and peptides including mucins, lactoferrin, lysozyme, lactoperoxidase, statherin, histatins and secretory immuonoglobulin A.

Hence, they concluded that "a balanced oral microbiome is important for the maintenance of oral health and symbiosis. Conditions associated with salivary gland hypofunction, impaired oral clearance, low salivary pH and altered salivary composition, often lead to perturbation of the function and composition of the oral microbiome causing dysbiosis, and an associated risk of oral disease."