Xerostomia (Dry Mouth)

Xerostomia or dry mouth, is a common, but sometimes overlooked, condition that is typically associated with salivary gland hypofunction (i.e., the objective measurement of reduced salivary flow).^{1, 2} Reduced salivary flow can cause difficulties in tasting, chewing, swallowing, and speaking; it can also increase the chance of developing dental decay, demineralization of teeth, tooth sensitivity, and/or oral infections.^{2, 3} There are a variety of potential causes of xerostomia, including adverse effects of medication, toxicity of chemotherapy and/or radiation therapy of the head and neck, autoimmune disease, other chronic disease, and nerve damage.⁴ Patients can be variably affected.⁴

Severity of dry mouth symptoms ranges from mild oral discomfort to significant oral disease that can compromise the patient’s health, dietary intake, and quality of life.^{1, 2} Estimates of xerostomia prevalence in the general population are imprecise because of limited data; estimates range from 0.9% to 64.8%.⁵ In people with Sjögren disease or in those receiving radiation therapy for head and neck cancer, the prevalence approaches 100%.⁵

Saliva is a mixture of secretions from the major (i.e., parotid, submandibular, sublingual) and minor salivary glands.⁶ In healthy individuals, the daily production of saliva normally ranges from 0.5 to 1.5 liters.⁷ Saliva is 99% water and contains a number of electrolytes (e.g., sodium, potassium, calcium, bicarbonate, phosphate) and organic components (e.g., immunoglobulins, proteins, enzymes, mucins).^{6, 8} In addition to keeping tissues moist and helping to digest food, saliva cleanses the oral cavity, makes it possible to chew and swallow food, maintains a neutral pH, and prevents demineralization.^{1, 3} Salivary proteins and mucins contribute to the lubrication and coating of oral tissues, protecting the mucosa from chemical, microbial, and physical injury.^1-3  Without adequate salivary flow, tooth decay and a variety of oral infections can develop.^{3, 6} Xerostomia symptoms may also worsen at night because salivary output reaches its lowest circadian levels during sleep and the problem can be exacerbated by mouth breathing.⁹

Reduced salivary flow can interfere with chewing or swallowing certain foods which may result in malnutrition.³ Significant loss of salivary gland function is associated with altered taste sensation (i.e., dysgeusia).^{1, 2, 7}

Drug/Therapy-Related

Medication-Induced Xerostomia.  The most frequent cause of hyposalivation is use of certain medications.¹⁰ According to the Surgeon General’s Report on Oral Health in America,¹¹ more than 400 over-the-counter (OTC) and prescription medications can contribute to or exacerbate oral dryness, including antihistamines (for allergy or asthma), antihypertensive medications, decongestants, pain medications, diuretics, muscle relaxants, and antidepressants.^{4-6, 12} The most common types of medications causing salivary dysfunction have anticholinergic effects, e.g., tricyclic antidepressants, antihistamines, antihypertensive medications, and antiseizure/antispasmodic drugs.¹³ Patients who are taking multiple medications may also be at a higher risk of dry mouth as an adverse effect of therapy.⁹

Drug substitutions may help reduce the dry mouth effects of certain medications (e.g., selective serotonin-reuptake inhibitor antidepressants tend to cause less dry mouth than tricyclic antidepressants).^{9, 13, 14} Dry mouth symptoms from medications may also be reduced if patients who are taking anticholinergic medications can take them during the day, rather than at night (avoiding nocturnal symptoms), and in divided doses, rather than one larger, single dose (potentially avoiding the xerostomic adverse effects of a larger dose).^{9, 13}

Toxicity Related to Cancer Chemotherapy or Head and Neck Cancer Radiotherapy.  Oral complications of cancer chemotherapy or head and neck cancer radiotherapy^{6, 13, 15} can be acute (i.e., develop during therapy) or chronic (i.e., develop months to years after therapy).¹⁵ These therapies can cause xerostomia/salivary gland hypofunction via direct toxicity to salivary glands and oral tissues or indirect damage due to regional or systemic toxicity.^{13, 15} Generally, cancer chemotherapy causes acute toxicities that resolve following discontinuation of therapy and healing of damaged tissue, whereas radiation therapy can cause acute oral toxicity, as well as induce permanent tissue damage that can put patients at lifelong risk.^{13, 15} Xerostomia can also occur following hematopoietic stem-cell transplantation.¹⁵ Sialadenitis, or infection of the salivary gland, is another potential acute oral toxicity associated with chemo/radiotherapy.¹⁵ Radioactive iodine, which is used to treat some thyroid cancers, can damage salivary glands (primarily the parotid glands) in a dose-dependent fashion.^{9, 13}

Physiological or Disease-Related

Aging. Xerostomia affects 30% of patients older than 65 years and up to 40% of patients older than 80 years; this is primarily an adverse effect of medication(s), although it can also result from comorbid conditions such as diabetes, Alzheimer’s disease, or Parkinson’s disease.^16-18 Xerostomia, while common among older patients, is more likely to occur in those with an intake of more than four daily prescription medications.¹⁸

Autoimmune Disease.  Sjögren disease (formerly known as Sjögren syndrome)¹⁹ is the second most common autoimmune connective-tissue disease¹⁹ and is the systemic condition most frequently associated with salivary dysfunction and xerostomia.⁹  Although Sjögren disease is a systemic condition that can affect any body organ or system, the primary symptoms are dry mouth and dry eyes.^{3, 6, 19} Sjögren disease causes chronic inflammation and dysfunction, resulting in salivary gland damage.¹⁹  Primary Sjögren disease (i.e., Sjögren disease alone) affects approximately 1 in 70 people; this number approximately doubles if patients with other major autoimmune or rheumatic disease in addition to Sjögren disease are included¹⁹ (i.e., secondary Sjögren disease⁹). Other autoimmune diseases that can occur with Sjögren disease include rheumatoid arthritis, systemic lupus erythematosus, scleroderma, polymyositis, and polyarteritis nodosa.⁹

Other Conditions.  Other conditions associated with dry mouth include:^{1-4, 6, 12}

• Cystic fibrosis
• Graft-versus-host disease
• Hepatitis C virus infection
• HIV infection/AIDS
• Hormonal changes (e.g., pregnancy or menopause)
• Lymphoma
• Nerve damage from a head or neck injury
• Poorly controlled diabetes
• Psychogenic causes
• Salivary gland agenesis or aplasia
• Stroke
• Uncontrolled hypertension

Potential lifestyle causes of xerostomia include the use of alcohol or tobacco, or the consumption of excessive caffeine or spicy food.⁴

Xerostomia can cause the following complications:^{1-3, 10, 12, 13, 20}

• a sticky, dry, or burning feeling in the mouth
• trouble chewing, swallowing, tasting, or speaking
• altered taste or intolerance for spicy, salty, or sour foods or drinks
• a dry or sore throat
• cracked, peeling, or atrophic lips
• a dry, rough tongue
• mouth sores
• an infection in the mouth
• hoarseness
• halitosis (bad breath)
• inability to retain dentures or otherwise poorly fitting removable prostheses

The goals of treating xerostomia include identifying the possible cause(s), relieving discomfort, and preventing complications, e.g., dental caries and periodontal infections.⁴

Identification

Patients with complaints of dry mouth should have a detailed health history (medical and dental) performed to help with early detection and identification of potential underlying causes.^{1, 2, 9} In patients with xerostomia or salivary gland hypofunction, oral examination may reveal dry and friable oral mucosa and the tongue may appear dry and fissured.^{1, 2, 5} Patients may commonly have dental caries (especially root, cervical, or incisal/cuspal tips), plaque accumulation, gingivitis, and/or periodontitis.^{1, 2, 5, 20} Infections (e.g., oral candidiasis) and enlargement of salivary glands from sialadenitis may also be present.^{1, 2, 5, 9, 20} Other oral manifestations evident on examination may include angular cheilitis, mucositis, traumatic oral lesions, and/or difficulty in wearing/retaining oral prostheses.^{5, 9, 20}

A thorough head and neck examination, including an intraoral evaluation to identify the presence or absence of salivary pooling on the floor of the mouth, can help a dentist identify who will benefit from further diagnostic evaluations, such as salivary flow rate measurement, minor salivary gland biopsy, or blood and microbial tests.^{1, 2} A patient is considered to have reduced salivary flow if the unstimulated salivary flow is 0.1 mL/min or less (measured for 5 to 15 minutes) or if the chewing-stimulated salivary flow is 0.7 mL/min or less (measured for 5 minutes).^{5, 20}

General Palliative/Preventive Interventions

Management of xerostomia and hyposalivation should emphasize patient education and lifestyle modifications.^{1, 2} Various palliative and preventive measures, including pharmacologic treatment with salivary stimulants, topical fluoride, saliva substitutes, and use of sugar-free gum/mints may alleviate some symptoms of dry mouth and may improve a patient’s quality of life.^{1, 2, 5}

Patients should be counseled on lifestyle tips for relieving dry mouth; these include:^{9, 12}

• sipping water or sugarless, caffeine-free drinks
• sucking on ice chips
• using lip lubricants frequently (e.g., every 2 hours)
• chewing sugar-free gum or sucking on sugar-free candy⁹
• avoiding salty or spicy food or dry, hard-to-chew foods⁹
• avoiding sticky, sugary foods
• avoiding irritants such as alcohol (including alcohol-containing mouth rinses5), tobacco, and caffeine
• drinking fluids while eating carefully^{6, 9}
• using a humidifier at night⁹

Dental and oral health-specific recommendations from the National Institute for Dental and Craniofacial Research³ and others^{5, 9, 13} include the following for patients with dry mouth:

• brush teeth gently at least twice a day with fluoridated toothpaste
• floss teeth every day
• schedule dental visits at least twice a year (with yearly bitewing radiographs)
• use of a prescription-strength fluoride gel (0.4% stannous fluoride, 1.0% sodium fluoride) daily to help prevent dental decay
• prompt treatment of oral fungal or bacterial infections
• application of 0.5% fluoride varnish to teeth
• dental soft- and hard-tissue relines of poorly fitting prostheses and use of denture adhesives

Salivary Stimulants.  Salivary stimulants should be considered in patients with residual salivary gland function.^{9, 12}  Sugar-free chewing gum, candies, and mints can be used to stimulate salivary output.9 The FDA has approved the oral secretagogues pilocarpine (Salagen®, Eisai and generics)²¹ and cevimeline hydrochloride (Evoxac® capsules, Daiichi-Sankyo and generics)²² to treat symptoms of dry mouth.^{10, 13} Pilocarpine is typically administered at a dose of 5 mg three times a day for at least 3 months and cevimeline is prescribed at a dose of 30 mg three times a day for at least 3 months.¹⁰  Adverse effects include sweating, cutaneous vasodilation, nausea and vomiting, diarrhea, hiccup, hypotension and bradycardia, increased urinary frequency, bronchoconstriction, and vision problems.¹⁰

Artificial Saliva/Saliva Substitutes/Oral Moisturizers. Artificial saliva products are available with or without prescription.  They typically contain a combination of carboxymethylcellulose and glycerin to increase viscosity, as well as buffering and flavoring agents (e.g., sorbitol, xylitol), and calcium and phosphate ions;^{4, 23} however, they do not contain the digestive and antibacterial enzymes or other proteins and minerals of biologic saliva.²³ Some products also contain fluoride.⁴ A prescription-only product, NeutraSal® (OraPharma, Inc.), is a supersaturated calcium phosphate rinse available as powder for reconstitution.²⁴

The ADA Seal of Acceptance category for products for temporary relief of dry mouth means that the product is safe and has shown efficacy in temporarily relieving dry mouth symptoms, when used as directed.

Saliva substitutes are used as often as needed and although they do not cure dry mouth, they can provide temporary relief of symptoms.^{4, 23} Alcohol-free mouth rinses, lozenges, and moisturizing oral sprays and gels are marketed as OTC oral care options for patients with dry mouth.^{4, 6, 9} There are also toothpastes specifically formulated for use in patients with dry mouth.^{4, 6}

A 2011 Cochrane Review^{25, 26} found “no strong evidence” that any specific topical therapy (e.g., sprays, lozenges, mouth rinses, gels, oils, chewing gum, or toothpastes) was effective for relieving the symptoms of dry mouth. Although chewing gum was shown to increase saliva production, there was no strong evidence that dry mouth symptoms were improved. The authors noted that “patient preference is an important consideration, together with consideration of the potential adverse effects.” The review concluded that, “Well designed, adequately powered randomised controlled trials of topical interventions for dry mouth, which are designed and reported according to CONSORT guidelines, are required to provide evidence to guide clinical care.”

1. Plemons JM, Al-Hashimi I, Marek CL, American Dental Association Council on Scientific A. Managing xerostomia and salivary gland hypofunction: Executive summary of a report from the American Dental Association Council on Scientific Affairs. J Am Dent Assoc 2014;145(8):867-73.
2. Wolff A, Joshi RK, Ekström J, et al. A guide to medications inducing salivary gland dysfunction, xerostomia, and subjective sialorrhea: A systematic review sponsored by the World Workshop on Oral Medicine VI. Drugs R D 2017;17(1):1-28.
3. Plemons JM, Al-Hashimi I, Marek CL Managing xerostomia and salivary gland hypofunction: A report of the American Dental Association Council on Scientific Affairs. American Dental Association. February 2015. "https://ada.org//-/media/project/ada-organization/ada/ada-org/ada/ada/science-and-research/files/csa_managing_xerostomia.pdf". Accessed July 2, 2019.

4. Lynge Pedersen AM, Belstrøm D. The role of natural salivary defences in maintaining a healthy oral microbiota. Journal of Dentistry 2019;80:S3-S12.

5. National Institute of Dental and Craniofacial Research. Dry mouth (nih publication no. 14-3174). National Institutes of Health. "https://www.nidcr.nih.gov/oralhealth/Topics/DryMouth/DryMouth.htm". Accessed July 2, 2019.

6. Terrie YC. Dry mouth: More common and less benign than thought. Pharmacy Times. February 10, 2016. "https://www.pharmacytimes.com/view/dry-mouth-more-common-and-less-benign-than-thought". Accessed July 2, 2019.

7. Ying Joanna ND, Thomson WM. Dry mouth - an overview. Singapore Dent J 2015;36:12-7.

8. Furness S, Bryan G, McMillan R, Birchenough S, Worthington HV. Interventions for the management of dry mouth: Non-pharmacological interventions. Cochrane Database Syst Rev 2013(9):Cd009603.

9. Agostini BA, Cericato GO, Silveira ERD, et al. How common is dry mouth? Systematic review and meta-regression analysis of prevalence estimates. Braz Dent J 2018;29(6):606-18.

10. Cohen-Brown G, Ship JA. Diagnosis and treatment of salivary gland disorders. Quintessence Int 2004;35(2):108-23.

11. Mese H, Matsuo R. Salivary secretion, taste and hyposalivation. J Oral Rehabil 2007;34(10):711-23.

12. Miranda-Rius J, Brunet-Llobet L, Lahor-Soler E, Farre M. Salivary secretory disorders, inducing drugs, and clinical management. Int J Med Sci 2015;12(10):811-24.

13. Dawes C, Pedersen AM, Villa A, et al. The functions of human saliva: A review sponsored by the world workshop on oral medicine vi. Arch Oral Biol 2015;60(6):863-74.

14. Turner MD, Ship JA. Dry mouth and its effects on the oral health of elderly people. J Am Dent Assoc 2007;138 Suppl:15S-20S.

15. Eyigor S. Dysphagia in rheumatological disorders. World Journal of Rheumatology 2013;3(3):45-50.

16. Parisis D, Chivasso C, Perret J, Soyfoo MS, Delporte C. Current state of knowledge on primary sjögren's syndrome, an autoimmune exocrinopathy. Journal of clinical medicine 2020;9(7):2299.

17. Villa A, Connell CL, Abati S. Diagnosis and management of xerostomia and hyposalivation. Ther Clin Risk Manag 2015;11:45-51.

18. Tan ECK, Lexomboon D, Sandborgh-Englund G, Haasum Y, Johnell K. Medications that cause dry mouth as an adverse effect in older people: A systematic review and metaanalysis. Journal of the American Geriatrics Society 2018;66(1):76-84.

19. U.S. Food and Drug Information Dry mouth? Don't delay treatment. Consumer Health Information. "https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm254273.htm". Accessed July 2, 2019.

20. Navazesh M, Kumar SK. Xerostomia: Prevalence, diagnosis, and management. Compend Contin Educ Dent 2009;30(6):326-8, 31-2; quiz 33-4.

21. Ship JA. Diagnosing, managing, and preventing salivary gland disorders. Oral Dis 2002;8(2):77-89.

22. Pratt M, Stevens A, Thuku M, et al. Benefits and harms of medical cannabis: A scoping review of systematic reviews. Syst Rev 2019;8(1):320.

23. Scully C. Drug effects on salivary glands: Dry mouth. Oral Dis 2003;9(4):165-76.

24. P.D.Q. Supportive Palliative Care Editorial Board. Oral complications of chemotherapy and head/neck radiation (pdq(r)): Health professional version. Pdq cancer information summaries. Bethesda (MD): National Cancer Institute (US); 2002.

25. Stein P, Aalboe J. Dental care in the frail older adult: Special considerations and recommendations. J Calif Dent Assoc 2015;43(7):363-8.

26. Jablonski RY, Barber MW. Restorative dentistry for the older patient cohort. Br Dent J 2015;218(6):337-42.

27. Yellowitz JA, Schneiderman MT. Elder's oral health crisis. J Evid Based Dent Pract 2014;14 Suppl:191-200.

28. Villa A, Abati S. Risk factors and symptoms associated with xerostomia: A cross-sectional study. Australian Dental Journal 2011;56(3):290-95.

29. Zero DT, Brennan MT, Daniels TE, et al. Clinical practice guidelines for oral management of Sjögren disease: Dental caries prevention. J Am Dent Assoc 2016;147(4):295-305.

30. Brandt JE, Priori R, Valesini G, Fairweather D. Sex differences in Sjögren's syndrome: A comprehensive review of immune mechanisms. Biology of sex differences 2015;6:19-19.

31. Fox PC, Ship JA. Salivary gland diseases. Burket's oral medicine, diagnosis & treatment: People's Medical Publishing House USA Ltd (PMPH); 2008. p. 191-222.

32. Tanaka A KS. Xerostomia and patients' satisfaction with removable denture performance: Systematic review. 2021;52(1):46-55.

33. Hayes M, Da Mata C, Cole M, et al. Risk indicators associated with root caries in independently living older adults. Journal of Dentistry 2016;51:8-14.

34. Villa A, Wolff A, Narayana N, et al. World workshop on oral medicine vi: A systematic review of medication-induced salivary gland dysfunction. Oral Dis 2016;22(5):365-82.

35. Eisai Inc. Salagen (pilocarpine hydrochloride) tablets (rev. 6/2018). "https://dailymed.nlm.nih.gov/dailymed/getFile.cfm?setid=fb4810ec-d26f-429d-b87c-5898a7870169&type=pdf&name=fb4810ec-d26f-429d-b87c-5898a7870169". Accessed July 2, 2019.

36. Daiichi-Sankyo Inc. Evoxac (cevimeline hydrochloride) capsules (rev. 04/2018). "http://www.evoxac.com/". Accessed July 2, 2019.

37. Han P, Suarez-Durall P, Mulligan R. Dry mouth: A critical topic for older adult patients. Journal of Prosthodontic Research 2015;59(1):6-19.

38. OraPharma Neutrasal (supersaturated calcium phosphate) powder for reconstitution. "https://www.neutrasalprofessional.com/". Accessed July 2, 2019.

39. Chiappelli F. No strong evidence that any topical treatment is effective for relieving the sensation of dry mouth. Evid-based Dent 2012;13(1):16-17.

40. Furness S, Worthington HV, Bryan G, Birchenough S, McMillan R. Interventions for the management of dry mouth: Topical therapies. Cochrane Database Syst Rev 2011(12):Cd008934.

• ADA Council on Scientific Affairs Report (2015): Managing xerostomia and salivary gland hypofunction—executive summary and full report
• ADA Professional Product Review:  Palliative Over-the-Counter (OTC) Treatments for Oral Dryness and Inflammation (PDF; pages 21-24)
• ADA Oral Health Topics:  Aging and Dental Health; Sjögren Disease
• Search JADA for articles related to xerostomia, salivary gland hypofunction, or dry mouth
• ADA Library & Archives

• Dry Mouth
• Dry Mouth Quiz
• Medications and Oral Health
• Saliva
• Sjögren’s Syndrome

• Managing dry mouth (February 2015)
• Oral health concerns for older adults (February 2016)
• Oral health during cancer treatment (January 2019)
• Oral moisturizers: Products that can help relieve dry mouth (July 2007)