Dry Mouth: Causes and mechanisms

What causes dry mouth?

The causes of dry mouth

Taking medication is the number one cause¹ of dry mouth as it is a side effect of many common medicines^2,3
Taking 4 or more medications may increase the risk of dry mouth by 40%⁴

Other causes include conditions such as Sjögren’s syndrome, diabetes and salivary gland damage^5,6

Salivary gland hypofunction

Dry mouth is associated with changes in saliva composition and may have no immediately identifiable cause.^3,5 Salivary gland hypofunction – the objective measurement of reduced salivary flow – can be associated with:^3,5,7,8

Medical treatments and polypharmacy
Lifestyle choices
Health conditions
Damage to the salivary glands

Salivary gland physiology

Three main salivary glands produce 90% of saliva.⁵ These glands produce the two major types of secretion that form saliva:⁵

Serous fluid (mainly from the parotid and submandibular glands)
Mucous (mainly from the submandibular and sublingual glands)

Salivary flow

Abnormal salivary flow can lead to dry mouth^3,5

Total salivary output should be approximately 1 litre per day, with salivary flow rates fluctuating naturally over this time.⁸ Patients may only realize that they have dry mouth when their natural salivary flow has decreased by almost half.⁸
Pharmacologic factors

Medication use is the number one cause of dry mouth^1,2,10

Over 500 medications are associated with dry mouth,^5,11 including many over-the-counter and commonly prescribed medications such as antihistamines, antidepressants, diuretics and cytotoxic drugs.^1,2,10,12 Furthermore, the risk of dry mouth increases in people who take two or more medications.^4,9

Other factors

Other causes of dry mouth

Besides medication use, there are various other physiological, behavioural, psychological and medical causes of dry mouth.

Lifestyle factors	Mouth breathing^5,10 Nasal obstruction⁵ Smoking¹⁰ Alcohol/drug abuse¹⁰ Caffeine¹⁰
Medical treatments	Damage from radiation therapy for head and neck cancers^{2,5,10,11,13–15} Chemotherapy^13,14 Physical trauma to the salivary glands⁶ Surgical removal of salivary glands⁵
Community acquired infections	HIV-1 infection^{2,5,10,11,13,15} Hepatitis C^2,5,11,12,15
Psychiatric disorders	Anxiety^5,13 Depression^5,13,15
Genetic disorders	Cystic fibrosis^2,11,15
Autoimmune diseases	Sjögren's syndrome^1,2,5,10,15 Rheumatoid arthritis^13,15

For all day & night symptom relief from dry mouth

Impact on patient quality of life

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Diagnosis

Explore an overview of diagnosing issues with Dry Mouth

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Management

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Dry Mouth

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The Biotène range

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Patient care resources

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References

Turner MD, Ship JA. Dry mouth and its effect on the oral health of elderly people. The Journal of the American Dental Association 2007; 138:S15–S20.
Scully C. Drug effects on salivary glands: dry mouth. Oral Diseases 2003; 9:165–176.
Sreebny LM, Vissink A (eds). “Dry mouth: a multifaceted diagnostic dilemma.” In Dry mouth, the malevolent symptom: a clinical guide. Oxford: Wiley-Blackwell, 2010; 33-61.
Nederfors T, Isaksson R, Mörnstad H, Dahlöf C. Prevalence of perceived symptoms of dry mouth in an adult Swedish population – relation to age, sex and pharmacotherapy. Community Dentistry and Oral Epidemiology 1997; 25:211–216.
Cassolato SF, Turnbull RS. Xerostomia: Clinical Aspects and Treatment. Gerodontology 2003; 20(2):64–77.
Sreebny LM, Schwartz SS. A reference guide to drugs and dry mouth – 2nd edition. Gerodontology 1997; 14(1):33–47.
Whelton HP. “Introduction: the anatomy and physiology of the salivary glands”. In Saliva and oral health (2nd ed.), edited by Edgar WM, O’Mullane DM. London: British Dental Association, 1996; 1–36.
Guggenheimer J, Moore PA. Xerostomia – etiology, recognition and treatment. The Journal of the American Dental Association 2003; 134:61–69.
Sreebny LM, Valdini A, Yu A. Xerostomia. Part II: Relationship to nonoral symptoms, drugs, and diseases. Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology 1989; 68(4):419–427.
Kleinegger CL. Dental Management of Xerostomia – Opportunity, Expertise, Obligation. The Journal of the California Dental Association 2007; 35:417–424.
Porter SR, Scully C, Hegarty AM. An update on the etiology and management of xerostomia. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 2004; 97:28–46.
Plemons JM, Al-Hashimi, Marek CL. Managing xerostomia and salivary gland hypofunction: Executive summary of a report from the American Dental Association Council on Scientific Affairs. The Journal of the American Dental Association 2014; 145:867–873.
Visvanathan V, Nix P. Managing the patient presenting with xerostomia: a review. The International Journal of Clinical Practice 2010; 64:404–407.
Wind DA. Management of Xerostomia: An Overview. The Journal of Practical Hygiene 1996; 1:23–27.
von Bültzingslöwen I, et al. Salivary dysfunction associated with systemic diseases: systematic review and clinical management recommendations. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 2007; 103:S57.e1–S57.e15.

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Dry Mouth: Causes and mechanisms

What causes dry mouth?

The causes of dry mouth

Salivary gland hypofunction

Salivary gland physiology

Abnormal salivary flow can lead to dry mouth3,5

Medication use is the number one cause of dry mouth1,2,10

Other causes of dry mouth

For all day & night symptom relief from dry mouth

Impact on patient quality of life

Diagnosis

Management

Dry Mouth

The Biotène range

Patient care resources

References

Abnormal salivary flow can lead to dry mouth^3,5

Medication use is the number one cause of dry mouth^1,2,10