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How the body communicates via its spit

Jan. 13, 2023
Amber Auger is "obsessed" with saliva because it reveals so much about what's going on with the body. But dental professionals don't evaluate this "liquid gold" nearly enough.

If you follow me on social media or have attended one of my lectures, you know I’m obsessed with saliva. This is because the more I learn about this "liquid gold," the more I feel dental professionals are underutilizing what it can communicate to us.

I've provided dental services to many people, including in villages in Kenya and Nigeria. When I tell hygienists this, they want to know the people’s rates of dental caries and periodontal disease. It all depends on their diet and lifestyle choices, but most of the patients do not have the level of disease that US patients have.

Of course, periodontal disease and caries are multifactorial. Still, saliva gives us clues about what the body needs to create a symbiotic environment to promote remineralization and pH balance. This can be used to detect biomarkers affecting a patient's systemic health.

Related reading

Salivary diagnostics: The 411
Spit matters: Collecting critical data in the quest for oral homeostasis

Saliva responsibility

Let's review what saliva is designed to do when it’s in a healthy state. Saliva's functions include antibacterial defense, protection, facilitation of taste, digestion, ionic exchange between tooth surfaces, and buffering action, which is imperative to a person's overall health.1 Here I’ll focus on biomarkers we can test while working with patients chairside: pH, periodontal pathogens testing, and xerostomia evaluation.

Biomarker pH

Oral pH has been discussed for many years in the dental community, yet most offices don’t offer pH testing while a patient is chairside. The pH is a critical aspect of a patient's saliva and ability to reduce the incidence of caries and periodontal disease. This is because when a patient has a pH lower than 5.5, calcium and phosphate from the tooth are reduced, which leads to demineralization. If the tooth doesn’t receive these ions, it cannot remineralize.2 This lack of remineralization will lead to caries. Additionally, periodontal pathogens are more active if the mouth's pH is acidic.2

We need to educate patients about common misconceptions that wreak havoc on the saliva's ability to buffer and neutralize the pH. Seltzer, white wines, and sugar-free sports drinks have a pH that ranges between 2 and 5.3 Although these drinks may not taste acidic, they drop the pH of the mouth every time a patient takes a sip. This includes many bottled waters, and how the water is distilled determines the pH.3

Biomarker periodontal pathogens

We learned about the five red-complex bacteria in our dental hygiene curriculum, but many US offices don't implement pathogen testing. You probably have those patients who have meticulous home care, with virtually no biofilm and limited calculus, but who have 7 mm bleeding chronic pockets. These patients have been compliant with every single recommendation you've made. You feel like you've failed them, their cases have you stumped, and you refer them out, only to have them ping-ponged around trying to find the root cause of their inflammation.

The solution to a patient's oral health success is identifying what periodontal pathogens are present, then selecting the home care and chairside technologies to destroy the pathogens. Without a healthy mouth, there can’t be a healthy gut, heart, and brain.4,5

Biomarker xerostomia

Patients with xerostomia cannot buffer the pH of their mouths as quickly as those with a healthy flow rate of saliva.5 This not only increases the rate of tooth decay but can be a critical factor for dental disease in patients with significant tissue and enamel destruction despite low biofilm rates. Most patients have normalized their xerostomia; therefore, we must assess their actual levels of xerostomia. The Challacombe chairside assessment is a time-effective way to measure this.6

To transform a patient's perspective and ability to control the rates of dental disease, we must look at what the saliva is trying to convey to us. Throughout this year, I will be covering root cause dental hygiene to help hygienists elevate the standards of care that were developed in 1989.7

Editor's note: This article appeared in the January/February 2023 print edition of RDH magazine. Dental hygienists in North America are eligible for a complimentary print subscription. Sign up here.


  1. Tiwari M. Science behind human saliva. J Nat Sci Biol Med. 2011;2(1):53-58. doi:10.4103/0976-9668.82322
  2. West NX, Hughes JA, Addy M. The effect of pH on the erosion of dentine and enamel by dietary acids in vitro. J Oral Rehabil. 2001;28(9):860-864. doi:10.1046/j.1365-2842.2001.00778.x
  3. Reddy A, Norris DF, Momeni SS, Waldo B, Ruby JD. The pH of beverages in the United States. J Am Dent Assoc. 2016;147(4):255-263. doi:10.1016/j.adaj.2015.10.019. Epub 2015 Dec 2.
  4. Melguizo-Rodríguez L, Costela-Ruiz VJ, Manzano-Moreno FJ, Ruiz C, Illescas-Montes R. Salivary biomarkers and their application in the diagnosis and monitoring of the most common oral pathologies. Int J Mol Sci. 2020;21(14):5173. doi:10.3390/ijms21145173
  5. Lamont RJ, Koo H, Hajishengallis G. The oral microbiota: dynamic communities and host interactions. Nat Rev Microbiol. 2018;16(12):745-759. doi:10.1038/s41579-018-0089-x
  6. Chengappa RK, Narayanan VS, Khan AM, Rakaraddi MP, Puttaswamy KA, Puttabuddi JH. Utility of two methodologies in the clinical assessment of oral dryness in postmenopausal women. J Midlife Health. 2016;7(3):114-118. doi:10.4103/0976-7800.191014
  7. Graskemper JP. The standard of care in dentistry: Where did it come from? How has it evolved? J Am Dent Assoc. 2004;135(10):1449-1455. doi:10.14219/jada.archive.2004.0056
About the Author

Amber Auger, MPH, RDH

Amber Auger, MPH, RDH, is an international lecturer, a 2019 Sunstar/RDH Award of Distinction recipient, editorial director for RDH Graduate, creator of Thrive in the Op, and certified Functional RDH. Amber has more than 18 years of experience in the dental field and has been practicing dental hygiene since 2010. An active mentor to fellow hygienists, she champions personal and professional growth through her innovative Thrive in the Op on-demand courses and live coaching sessions. She can be reached at [email protected].

Updated March 28, 2024