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Dry mouth issues: Getting to the root of the problem

July 1, 2019
Anne Nugent Guignon, MPH, RDH, CSP, discusses risk assessment for caries and dry mouth, along with dental products that can be used to treat xerostomia and hyposalivation.

The internet is an easy place to get an answer. Google searches are fast. As a profession, we are hardwired to help people, and folks in Facebook groups love to chime in with answers. Some only suggest products or protocols they personally like or use. Other comments are laden with personal biases or ignore scientific information. Since it is so easy to get a quick response, it is important to stop a moment and carefully determine if the information is accurate or even applicable.

Last week Haley posted a query regarding Greg, a patient who has been developing severe decay at a very rapid rate. Everyone was concerned—Greg, the doctor, and Haley. Greg was willing to try anything. Haley’s doctor asked her to investigate a workable, effective solution that would be easy to implement. Out of desperation, Haley reached out to her colleagues on Facebook. Within minutes, the questions started pouring in. She was looking for an effective solution to what is possibly a very complicated situation.

This is Haley’s original post:

Hey, guys—I need your help!

  • Male in his 60s
  • Severe recession
  • History of radiation for throat cancer
  • Rampant decay, progresses quickly
  • New advanced decay each visit

Please tell me how you/your office would handle this. I’ve already discussed diet, but I’m open to more suggestions related to diet. Looking for a Tx plan to prevent rampant decay. I need product names and a plan of action, please! I am thinking:

  • Fluoride trays—which product?
  • Varnish treatments—four times a year?
  • Saliva booster?
  • pH neutralizer?

Bottom line, it is critical to understand the “why” for each patient before recommending a product or treatment—and this is where it gets tricky. Tooth destruction is complex. It is more than exposure to sugar, how well patients clean their teeth, or a family history of decay. Caries is a complex disease that involves a huge uptick in acidogenic and aciduric microbes, while the critical tipping point in radiation-induced decay comes from dryness.1–4 In direct contrast, erosive tooth wear occurs when acids that are not of a bacterial origin soften tooth structure, which is removed with some kind of abrasive force.4,5 While each of these issues destroy valuable tooth structure, the reasons for the damage are quite different.

Haley’s original post did not provide enough information. There are some very important missing pieces to Greg’s puzzle. Each additional data point can lead to a targeted treatment plan that can actually work for Greg. It turns out that, despite radiation therapy, Greg still had some salivary flow. This little tidbit of information is critical and can impact what Haley can recommend for Greg, but Haley and Greg need to dig deeper. This has to be a joint project where everyone becomes a detective looking for clues everywhere.

A different approach to solving the problem

Years ago, it was common to go directly to the solutions phase. Today it is possible to follow an organized pathway that can direct treatment recommendations and protocols based on risk factors. The Caries Management by Risk Assessment (CAMBRA) protocol is designed to help clinicians create a pathway to success.6 Greg has a history of radiation so is automatically considered a very high-risk patient for decay and his clinical presentation is a direct result of risks that need more targeted management.

The scientific literature reports that between 20% and 30% of the population experiences dry mouth, and dry mouth’s prevalence tends to rise with age.6 People often have multiple dry mouth risk factors.1,4 Risk factors are not necessarily static and can either increase or decrease over time.1–3 Instituting a CAMBRA approach is a perfect way to find out what is going on.

Rather than rehash the well-known risk factors for dry mouth—medications, Sjögren’s disease, and head and neck radiation—this discussion looks at the complex range of risk factors that individually or combined increase the relative risk for dry mouth issues. Dry mouth is very uncomfortable for patients, and it sets the stage for caries, erosive tooth wear, dentinal hypersensitivity, and candidiasis infections.1,2,4,6

More dry mouth clues: Medical conditions and complications

The following medical conditions, complications, and treatments increase the risk for dry mouth. Obviously not all relate to Greg, but consider these conditions. Keep in mind that complex dental patients often have very complicated medical histories. These could be part of the dry mouth puzzle for your very next patient1,4:

  • Autoimmune diseases
  • Diabetes
  • Parkinson’s disease
  • Endocrine disorders
  • Pregnancy and nursing
  • Chronic fatigue syndrome
  • HIV and AIDS
  • Eating disorders
  • Laxative abuse
  • Hepatitis C
  • Alzheimer’s disease
  • Genetic disorders
  • Intestinal failure
  • COPD
  • Anxiety
  • Depression
  • Salivary gland dysfunction
  • End of life / terminal illness
  • Hemodialysis
  • Radiation treatment
  • Hormone imbalance
  • Cancer therapy
  • Liver transplantation
  • Menopause
  • Vitamin D deficiency

Dehydration also plays an important role in the development of dry mouth. While fluid intake is a factor, dehydration can also occur as a direct result of fluid loss from running a fever, vomiting, excessive sweating, chronic diarrhea, excessive blood loss, or a serious burn.1,4

Respiratory issues that exacerbate dry mouth include sleep apnea, mouth breathing, airway obstruction, asthma, nasal congestion, seasonal allergies, prolonged coughing, and exposure to dust, particulate matter, pet dander, plant pollens, mold, mildew, and air pollution, such as ozone, smoke from fires, and industrial waste and discharges.1,4

Lifestyle and climate

Climate is often overlooked. Mother Nature plays a heavy hand in this part of the puzzle. Desert climates are obvious, but the humidity drops significantly during cold winter months, especially where the temperatures drop well below freezing. Indoor central heating units dry the ambient air, thus reducing humidity levels. Following the first outbreak of Legionnaires’ disease in 1976, hotels and airplanes were constructed to superdry the air to reduce the risk of potentially fatal respiratory infections.1,4

Dental appliances, such as dentures, partials, bite guards, orthodontic aligners, sports mouth guards, and whitening trays, create a temporary dry microclimate in the mouth during the wear time.

Today’s lifestyle choices that exacerbate dry mouth issues include cigarette smoking, cannabis, vaping, recreational drugs, using a CPAP machine, prolonged speaking, and singing. Additional complications are emotional stress, anxiety or fear, heavy aerobic exercise that encourages mouth breathing, and excessive consumption of caffeine, alcohol, or salty foods.1,4

Food consumption patterns have changed dramatically over the past 50 years. Typically, fast foods, snacks, or foods that can have long shelf lives contain high levels of sodium. Many patients have a sodium intake that is three or even four times past the RDA. Excessive sodium intake contributes to dry mouth.1,4,5,7

Salivary flow rate, pH, buffering capacity, and microbes

Practices collect and record a lot of data: x-rays, probing depths, intraoral photos, existing restorations, and CT scans. But is your practice evaluating the saliva? Probably not. Understanding a patient’s saliva is a key to solving this mystery. It is important to know the quality, quantity, and the microbial activity.1,2,8

GC America has an inexpensive, easy-to-use product called the Saliva-Check Buffer Kit. There are three different tests: salivary pH, buffering capacity, and salivary flow rate. Each of these provides a key piece of information. Some people have acidic saliva and others have saliva that can’t buffer or neutralize acids. When the flow rate is low, there can be an increase in acid-producing microbes, as well as a reduced ability to buffer.

Dry mouth sets the stage for both caries and oral fungal infections. Specific microbes associated with caries frequent mixed biofilm communities.1,2,4 Two salivary screening tests from OralDNA can supply more information: OraRisk Caries tests for the presence of Streptococcus mutans, Streptococcus sobrinus, and Lactobacillus casei. These acidogenic microbes thrive in an acidic environment and rapidly metabolize dietary sugars and starches, producing acids that demineralize hard tooth structure. Candida organisms grow quickly and are heavy acid producers. OraRisk Candida tests for the presence of Candida albicans and other Candida species. Both S. mutans and C. albicans are implicated in the caries process, especially in severe cases. Both tests can be completed using one saliva sample. The combined lab fee for the two tests runs just over one hundred dollars. Positive findings from either test indicate a risk for caries.

Collecting more data: Diet

It’s easy to ask a few quick questions about what patients are eating or drinking, but it is even more important to discover everything that is passing through the oral cavity. Dietary factors that impact caries are complicated and include frequency, duration of contact, liquid versus solids, watery versus sticky, acid composition, the presence of fermentable carbohydrates, the temperature of the product, and products with additional ingredients such as citric, malic, tartaric, acetic, and lactic acids.1,5,7

Products that contain citric acid will stimulate salivary flow, but it is a highly erosive compound. Hidden culprits can include items such as chewable vitamin C supplements, water flavor enhancers, dried fruits, gummy vitamins and supplements, citrus-based teas, granola bars, nutritional supplements such as kombucha or apple cider vinegar, weight loss products, fruit-infused waters, and nutritional drinks formulated to supplement dietary intake.

It’s common for those with dry mouth to sip beverages all day. This not only creates frequent exposures, but also washes away the protective factors in saliva, including proteins, mucins, and enzymes. The warmer the beverage, the faster the erosive attack. Energy drinks and sports drinks contain multiple organic acids, which makes it more difficult for the saliva to neutralize the beverage acids.1,4,9

Synthesizing options to create a plan

It takes time to collect all of this information and data, and it is important to remember that people’s lives and situations change over time. New medications are added, habits change, medical conditions crop up, and dietary consumption can be altered. A variety of products can help patients achieve these goals. The range is simply amazing. It is not feasible to list every possible solution for patients like Greg or others you may encounter, but this will be a great head start in your path to helping these complex patients.

Fluoride’s role in dry mouth

Armed with this information, Haley and Greg can partner to figure out the big picture and determine exactly how to reduce his caries risk. Earlier, we found out that Greg has some salivary flow. This is good news. In order for fluoride to be actively incorporated into the tooth structure, moisture is needed in the mouth, along with adequate calcium and phosphorus. In Greg’s case, fluoride trays should work, but he could also benefit from using a prescription supersaturated calcium phosphate rinse, such as SalivaMax (Forward Science) or NeutraSal (OraPharma), multiple times a day to support a healthy electrolyte balance.9,10

Haley’s Facebook post posed a question about fluoride varnish. Given Greg’s complex challenge to stop the progression of root caries, fluoride varnish on a regular interval is not out of the question. The interval for a high-risk patient can be as short as every month to once every three months. The optimal interval is up to the patient and clinician. It is also important to understand that not all fluoride varnish products are the same, and all but one deposit fluoride where the varnish is applied. Most varnish products require drying the tooth surfaces prior to application. Hydrophilic products can be applied in moist environments. 3M Vanish Varnish has a unique benefit. This varnish can be applied in a moist environment, but the fluoride formulation will move across all tooth surfaces for 24 hours, providing the patient with a complete fluoride experience.

Considering fluoride and other options

There are many over-the-counter and prescription toothpastes, gels, and rinses that contain therapeutic levels of fluoride as well as other active and inactive ingredients. Toothpastes that have stabilized stannous fluoride formulations are beneficial and inexpensive; however, prescription products contain higher fluoride levels. Along with fluoride-based formulations, products can also contain varying levels of xylitol, humectants, polymers, arginine, polysaccharides, glycerine, essential oils, aloe vera extract, green tea, calcium, lipids, and phosphate. It is important to note that those with dry mouth often cannot tolerate a strong mint flavor. Flavors and textures vary per product, as do the application or usage protocols. It is important to recommend only nonerosive products. Products in this discussion have pH levels of 6 or greater.

Moisture, hydration, and lubrication are critical for mouthfeel and mucosal protection. Colgate’s Hydris Oral Rinse has cleared the FDA as a medical device to relieve the symptoms of dry mouth. This rinse is formulated with a combination of copolymers and humectants. Prisyna’s Moisyn Rinse and Spray also have FDA clearance and use a complex of chitosan, arginine, xylitol, and a humectant. 3M Xerostomia Relief Spray is lipid-based and available by prescription. Two Biotène products are included in this group: Oral Balance Dry Mouth Moisturizing Liquid and Dry Mouth Moisturizing Spray. The goal of each of these products is to keep moisture in contact with the tongue and mucosa for a long period of time.

Many patients feel the need to increase salivary flow rates. Xylitol is a five-carbon sugar that is not metabolized by caries microbes. It can be used to stimulate salivary flow rates, which can help patients achieve and maintain a neutral oral pH. A wide range of products are formulated with xylitol: mouth sprays, gels, lollipops, rinses, wipes, toothpastes, candies, gums, and slow-release lozenges and hard discs. Product flavors, mouthfeel, and substantivity vary. Popular xylitol products include Allday Dry Mouth Spray (Elevate Oral Care), Spry Rain (Xlear), and slow-release lozenges such as XyliMelt discs (OraCoat), Nuvora’s Salese (which also contains essential oils), MighTeaFlow (Camellix), and Act Dry Mouth. Safe mouth rinses include Act Soothing Mint Mouthwash and MighTeaFlow Neutral pH Spray. Xylitol products resembling candy include 3M TheraMints, Ice Chips, Sparks, CariFree Lollipops, and many brands of gum.

Arginine’s role in dry mouth and caries

Arginine bicarbonate and calcium carbonate contribute significantly to oral health, especially for those who deal with dry mouth. Arginine’s contribution is more subtle than salivary stimulation or soft-tissue comfort. Current research indicates that multiple oral microbes have the capacity to metabolize arginine, an amino acid commonly found in saliva. These microbes produce ammonia as a metabolic by-product.11 Regular use of arginine-containing products results in sustained alkali release. The sustained release keeps the oral pH neutral and supports a healthy biofilm ecology that favors remineralization.12 There are currently two over-the-counter products that contain arginine bicarbonate and calcium carbonate: Tom’s of Maine Rapid Relief Sensitive Toothpaste and BasicBites chews (Ortek).

Final thoughts

Homeostasis is a key to supporting a healthy oral environment in the face of dry mouth. Acidogenic and aciduric microbes are not able to survive and thrive in environments with a pH of 7, and neither can Candida. Creating and sustaining an environment with a neutral pH is a key to combating caries infections, erosion, and Candida-based fungal infections.13 Research experts are working diligently on new, innovative solutions that clinicians will be able to recommend and implement, but in the meantime, there are many outstanding choices for our patients.

Greg is lucky that Haley is his hygienist, and Haley is lucky to have Greg, a patient who is willing to try anything. Together they can and will find a way for Greg to take control of his oral health and stop his ongoing and progressive caries issues.


1.    Sreebny LM, Vissink A. Dry Mouth, The Malevolent Symptom: A Clinical Guide. Hoboken, NJ: Wiley-Blackwell; 2010.

2.     Marsh PD. Are dental diseases examples of ecological catastrophes? Microbiology. 2003;149(2):279-294.

3.     Anil S, Vellappally S, Hashem M, Preethanath RS, Patil S, Samaranayake LP. Xerostomia in geriatric patients: a burgeoning global concern. J Investig Clin Dent. 2016;7(1):5-12. doi:10.1111/jicd.12120.

4.     Birgnajje WS, Taylor GW, Anderson PF, Shannon C. Dry mouth (xerostomia): Diagnosis, causes, complications and treatment. Research Review; 2011. https://www.deltadentalct.com/dentists/downloads/DryMouthDentalProfessionals.pdf. Accessed May 30, 2019.

5.     Lussi A, Schlueter N, Rakhmatullina E, Ganss C. Dental erosion--an overview with emphasis on chemical and histopathological aspects. Caries Res. 2011;45(Suppl 1):2-12. doi:10.1159/000325915.

6.     Rechmann P, Chaffee BW, Rechmann BMT, Featherstone JDB. Caries Management by Risk Assessment: Results from a Practice-Based Research Network Study. J Calif Dent Assoc. 2019;47(1):15-24.

7.     Barbour ME, Lussi A. Erosion in relation to nutrition and the environment. Monogr Oral Sci. 2014;25:143-54.

8.     Longman LP, McCracken CF, Higham SM, Field EA. The clinical assessment of oral dryness is a significant predictor of salivary gland hypofunction. Oral Dis. 2000;6(6):366-370.

9.     Mandel ID. The functions of saliva. J Dent Res. 1987;66(Spec No):623-627.

10.  Ekstrom J, Khosravani N, Castagnola M, Messana I. Saliva and its control of secretions. In: Ekberg O, ed. Dysphagia Medical Radiology. Berlin, Germany: Springer Berlin Heidelberg; 2012:19-47.

11.  Burne RA, Zeng L, Ahn SJ, et al. Progress dissecting the oral microbiome in caries and health. Adv Dent Res. 2012;24(2):77-80. doi:10.1177/0022034512449462.

12.  Nascimento MM. Potential uses of arginine in dentistry. Adv Dent Res. 2018;29(1):98-103. doi:10.1177/0022034517735294

13.  Jenkinson HF, Douglas LJ. Chapter 18: Interactions between Candida species and bacteria in mixed infections. In: Brogden KA, Guthmiller JM, eds. Polymicrobial Diseases. Washington, DC: ASM Press; 2002. www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=pmd&part=A2773#A. Accessed May 30, 2019.

ANNE NUGENT GUIGNON, MPH, RDH, CSP, provides popular programs on topics that include biofilms, ergonomics, hypersensitivity, power-driven scaling, and remineralization. The recipient of the 2004 Mentor of the Year Award and the 2009 ADHA Irene Newman Award, Anne has practiced clinical dental hygiene in Houston since 1971 and can be contacted at [email protected].
About the Author

Anne Nugent Guignon, MPH, RDH, CSP

ANNE NUGENT GUIGNON, MPH, RDH, CSP, has received numerous accolades over four decades for mentoring, research, and guiding her profession. As an international speaker and prolific author, Guignon focuses is on the oral microbiome, erosion, hypersensitivity, salivary dysfunction, ergonomics, and employee law issues. She may be contacted at [email protected].