Statement on Oral Fluid Diagnostics
ADA Council on Scientific Affairs
Saliva and other oral fluids play significant roles in supporting the health of soft and hard tissues in the oral cavity. The protective functions of saliva include maintaining a neutral oral pH, cleaning and remineralizing the dentition, facilitating swallowing and digestion, and protecting oral tissue against dessication and invasion by microorganisms. Dentists are keenly aware that adequate saliva is essential for maintaining oral health, and that reduced salivary secretion (hyposalivation) can contribute to multiple oral problems, such as dental caries, mucositis, fungal infections, and periodontal diseases.1-4
Along with protecting oral tissues, saliva has long been considered a "mirror of the body" that generally reflects the state of a patient’s overall health. A wide range of systemic diseases, such as diabetes and Sjögren’s syndrome, have oral manifestations that dentists encounter in patients at various stages of development. Based on these factors, dentists are ideally situated to monitor and treat oral disease progression, impaired salivary status, and various oral complications associated with systemic conditions.
In recent years, oral fluid has attracted widespread interest as a diagnostic medium for rapid, point-of-care testing. The advantages of using saliva for disease diagnostics include ease of access, noninvasive sample collection, increased acceptance by patients, and reduced risks of infectious disease transmission. Oral samples are readily accessible as whole saliva or by sampling secretions from specific glands, mucosal transudate, or gingival crevicular fluid.
Sampling oral fluids, instead of blood or urine, provides an attractive medium for detecting a range of candidate biomarkers, such as proteins, electrolytes, hormones, antibodies and DNA/RNA, as well as other substances such as therapeutic or recreational drugs.5-8 Ready access to oral biofluids is helpful for one-time sample collection, and an even greater benefit is realized when multiple or serial sampling is required for ongoing, real-time assessment of health and disease status, physiologic markers, or pharmacokinetics.
Analytes, such as protein and nucleic acid components, are usually present in lower concentrations in oral fluids than in blood. To address this barrier, proteomic technologies are now available that have significantly improved the ability to monitor and identify candidate biomarkers at the molecular level.9,10 With these technologies, scientists have made significant progress in cataloging the human salivary proteome and analyzing the potential diagnostic value of candidate oral fluid biomarkers.
To date, oral fluid diagnostic tests have already been developed to detect HIV status and substance abuse. Rapid, chairside diagnostic tests and biosensor technologies are currently under development to evaluate oral fluids for disease detection, which will also facilitate improved access and health care outcomes for patients. Oral fluid diagnostics may also play a significant role in both clinical practice and other venues, such as community and public health initiatives, long-term care facilities, and hospitals. At the same time, large-scale, multi-center clinical trials and independent validation studies are required before noninvasive oral fluid tests become commercially available for the early detection of oral cancer and other systemic conditions. Further refinement of oral fluid screening tests to help identify individuals at increased risk for oral and systemic diseases holds tremendous promise to elucidate our understanding of the relationship between oral health and overall health.
The Council recognizes the importance of continued research in oral fluid diagnostics, and welcomes the development of rapid, point-of-care tests that provide accurate measurements of clinically validated biomarkers. The Council strongly advocates interdisciplinary collaborations and expanded funding of research programs to evaluate the full diagnostic and predictive value of oral fluid-based tests and their translation into clinical applications for screening symptomatic or asymptomatic patients.
Advances in the science of oral fluid diagnostics may lead to identification of disease signature patterns of candidate biomarkers and/or confirmation of genetic susceptibility to some conditions. The speed and scope of available tests are also likely to increase. As oral fluid diagnostic applications advance, the Council encourages dentists to take leadership roles in integrating the tests and related technologies into clinical practice, consistent with the best available scientific evidence.
In the larger health care community, dentists and oral health professionals may be positioned to expand the reach and impact of preventive medicine through the application of cost-effective and non-invasive oral fluid screening tests and referring patients for necessary medical care. The Council will continue to pursue actions to help the profession understand the science and technologies of oral fluid-based diagnostics as they evolve in this important field of research.
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9. Hu S, Xie Y, Ramachandran P, et al. Large-scale identification of proteins in human salivary proteome by liquid chromatography/mass spectrometry and two-dimensional gel electrophoresis-mass spectrometry. Proteomics 2005;5:1714–28.
10. Denny P, Hagen FK, Hardt M, et al. The proteomes of human parotid and submandibular/sublingual gland salivas collected as the ductal secretions. J Proteome Res. 2008 May;7(5):1994-2006.