An adequate supply of saliva is critical to the preservation and maintenance of oral tissue. Clinicians often do not value the many benefits of saliva until quantities are decreased. Much is written on the subject of salivary hypofunction, but little attention is paid to normal salivary flow and function. This article is a brief, up-to-date overview of the literature on the basics of normal salivary composition, flow, and function. A review of the literature was conducted using MEDLINE and Healthstar (1944 through 1999); articles were selected for inclusion on the basis of relevance and significance to the clinician.

A review of saliva: Normal composition, flow, and function

This review examines the diagnostic application of saliva for systemic diseases. As a diagnostic fluid, saliva offers distinctive advantages over serum because it can be collected non-invasively by individuals with modest training. Furthermore, saliva may provide a cost-effective approach for the screening of large populations. Gland-specific saliva can be used for diagnosis of pathology specific to one of the major salivary glands. Whole saliva, however, is most frequently used for diagnosis of systemic diseases, since it is readily collected and contains serum constituents. These constituents are derived from the local vasculature of the salivary glands and also reach the oral cavity via the flow of gingival fluid. Analysis of saliva may be useful for the diagnosis of hereditary disorders, autoimmune diseases, malignant and infectious diseases, and endocrine disorders, as well as in the assessment of therapeutic levels of drugs and the monitoring of illicit drug use.

https://journals.sagepub.com/doi/pdf/10.1177/154411130201300209

The Diagnostic Applications of Saliva— A Review:

SUMMARY The pursuit of timely, cost-effective, accurate, and noninvasive diagnostic methodologies is an endeavor of urgency among clinicians and scientists alike. Detecting pathologies at their earliest stages can significantly affect patient discomfort, prognosis, therapeutic intervention, survival rates, and recurrence. Diagnosis and monitoring often require painful invasive procedures such as biopsies and repeated blood draws, adding undue stress to an already unpleasant experience. The discovery of saliva-based microbial, immunologic, and molecular biomarkers offers unique opportunities to bypass these measures by utilizing oral fluids to evaluate the condition of both healthy and diseased individuals. Herewediscusssalivaanditssignificanceasasourceofindicators forlocal,systemic,andinfectiousdisorders.Wehighlightcontemporary innovations and explore recent discoveries that deem saliva a mediator of the body’s physiological condition. Additionally, we examine the current state of salivary diagnostics and its associated technologies, future aspirations, and potential as the preferred route of disease detection, monitoring, and prognosis.

Salivary Biomarkers: Toward Future Clinical and Diagnostic Utilities

The capability to assess physiological states, detect morbidity initiation and progression, and monitor post-treatment therapeutic outcomes through a noninvasive approach is one of the most desirable goals for healthcare research and delivery. Saliva, a multi-constituent oral fluid, has high potential for the surveillance of general health and disease. To reach the above goal through saliva-based diagnostics, two prerequisites must be fulfilled: (1) discovering biomarker(s) for different diseases among the complicated components of saliva, and (2) advancing sensitivity and specificity of biomarker(s) through persistent development of technologies. Under the support and research blueprint initiated by the National Institute of Dental and Craniofacial Research (NIDCR), salivary diagnostics has not only steadily progressed with respect to accuracy and availability, but has also bridged up-to-date nanotechnology to expand the areas of application. With collective efforts over several years, saliva has been demonstrated to be a promising bodily fluid for early detection of diseases, and salivary diagnostics has exhibited tremendous potential in clinical applications. This review presents an overview of the value of saliva as a credible diagnostic tool, the discovery of salivary biomarkers, and the development of salivary diagnostics now and in the future.

Saliva: an emerging biofluid for early detection of diseases

Oral mucosa heals faster than does skin, yet few studies have compared the repair at oral mucosal and cutaneous sites. To determine whether the privileged healing of oral injuries involves a differential inflammatory phase, we compared the inflammatory cell infiltrate and cytokine production in wounds of equivalent size in oral mucosa and skin. Significantly lower levels of macrophage, neutrophil, and T-cell infiltration were observed in oral vs. dermal wounds. RT-PCR analysis of inflammatory cytokine production demonstrated that oral wounds contained significantly less IL-6 and KC than did skin wounds. Similarly, the level of the pro-fibrotic cytokine TGF-b1 was lower in mucosal than in skin wounds. No significant differences between skin and mucosal wounds were observed for the expression of the anti-inflammatory cytokine IL-10 and the TGF-β1 modulators, fibromodulin and LTBP-1. These findings demonstrate that diminished inflammation is a key feature of the privileged repair of oral mucosa.

Differential Injury Responses in Oral Mucosal and Cutaneous Wounds

The predominant focus of research dealing with saliva revolves around the role in the maintenance of oral health through a number of physiological and biological properties of constituent proteins. An ever-expanding literature exists indicating that the salivary glands additionally synthesize, and secrete into saliva, a wide range of growth factors. Animal studies with epidermal growth factor have provided evidence for a role in both oral and systemic health, through the promotion of wound healing rates. Thus, the ability to manipulate their rates of synthesis and absorption from saliva holds the potential to enhance tissue regeneration and homeostasis.

M.G. Humphreys-Beher

Papers

Saliva and Growth Factors : The Fountain of Youth Resides in Us All