Dry mouth, medically known as xerostomia, occurs when the mouth does not produce enough saliva to remain adequately moist. The condition can cause discomfort, affect eating and speaking, and increase the risk of oral health problems.
Saliva plays several roles in maintaining oral health. It helps wash away food particles, lubricates the mouth to make chewing and swallowing easier, and neutralises acids that can damage tooth enamel. It also helps control oral bacteria and supports the minerals that keep teeth strong.
Reduced saliva production can therefore affect more than comfort, particularly when the condition persists.
Causes of reduced saliva
Dry mouth can affect people of any age, although it is more common among older adults. The condition is not an inevitable part of ageing, and persistent symptoms may indicate an underlying problem that requires medical assessment.
Dehydration is one possible cause because saliva consists largely of water. The condition can also occur as a side effect of medicines, including some antidepressants, muscle relaxants and pain relievers.
Cancer treatment is another potential cause. Radiation directed at the head and neck can damage salivary glands and reduce saliva production, while some chemotherapy treatments can change the amount or consistency of saliva.
Injuries or surgery affecting nerves in the head and neck may interfere with the signals that regulate saliva production. Surgical removal or damage of salivary glands can also contribute to the condition.
Other associated factors include breathing through the mouth, smoking or using tobacco, alcohol consumption and the use of certain recreational substances. Anxiety and stress can cause temporary dry mouth in some people.
Dry mouth may also be associated with medical conditions such as diabetes, HIV infection, stroke and Sjögren’s disease, an autoimmune condition that can affect the glands responsible for producing saliva and tears. The presence of dry mouth alone does not establish that a person has any of these conditions.
Symptoms and possible complications
People with dry mouth may experience persistent dryness or stickiness, thick saliva, cracked lips and bad breath. Other symptoms include a dry or sore throat, hoarseness, a rough or grooved tongue, changes in taste and difficulty chewing, speaking or swallowing.
People who wear dentures may also find them uncomfortable or difficult to use when the mouth lacks sufficient moisture.
The effects can extend to dental and general health. Reduced saliva allows food particles and plaque to accumulate more readily, increasing the risk of tooth decay and gum disease.
People with persistent dry mouth may also develop mouth sores, oral thrush, a fungal infection caused by Candida, or cracks at the corners of the mouth. When chewing and swallowing become difficult, eating may become uncomfortable and nutritional intake can suffer.
When to seek medical advice
People whose dry mouth persists should consult a dentist or doctor to establish the cause. Assessment may include reviewing medicines, examining the mouth and, where appropriate, conducting tests to investigate saliva production or possible underlying conditions.
Management depends on the cause. Drinking water regularly, chewing sugar-free gum to stimulate saliva, maintaining good oral hygiene and attending routine dental check-ups can help relieve symptoms and protect the teeth.
A health professional may recommend saliva substitutes or other treatments where necessary. If a medicine is suspected of causing the problem, patients should discuss possible alternatives or dosage adjustments with the prescribing professional rather than stopping treatment on their own.
