Dry Mouth (Xerostomia): Causes, Symptoms and Daily Care Advice

Dry mouth, known in medical terms as xerostomia, is a common complaint that arises when the flow of saliva decreases. Many people dismiss it as nothing more than passing thirst, yet saliva is one of the most important natural defence systems protecting the mouth. When the amount or the quality of saliva declines, the teeth, gums and oral mucosa become far more vulnerable. In this article we look at what xerostomia is, why it develops, how it shows itself and what can be done in daily life, from a patient-centred point of view.

What Is Dry Mouth (Xerostomia)?

Xerostomia is the sensation of not having enough saliva in the mouth. In some patients the salivary glands genuinely produce less saliva; in others production is normal, but the saliva has become thicker and stickier and no longer moistens the mouth adequately. In both cases the patient describes a mouth that feels dry throughout the day, a tongue that sticks to the palate and a frequent need to sip water while speaking.

Xerostomia is not a disease in itself; more often it is a symptom. Behind it there may be a medicine being taken, a systemic condition or a lifestyle-related factor. For this reason, patients with persistent dry mouth are advised to be assessed both by a dentist and by the relevant medical doctor.

The Role of Saliva in Oral Health

Saliva is not simply a fluid that keeps the mouth wet. It is a versatile protective system working quietly all day long:

• Buffering: It neutralises the acid produced after food and drink, restoring the balance of pH in the mouth.
• Remineralisation: With the calcium and phosphate minerals it contains, it helps return minerals dissolved from the enamel surface during an acid attack.
• Cleansing: It mechanically washes away food debris and bacterial plaque.
• Antibacterial effect: Thanks to its enzymes and immune proteins, it helps limit the overgrowth of bacteria and fungi.
• Comfort and function: It makes chewing, swallowing, speaking and tasting easier, and supports the fit of dentures against the mucosa.

When these functions are lost, the oral environment becomes far more hospitable to bacteria. Xerostomia is therefore regarded as an important risk factor for the formation of tooth decay.

Causes of Dry Mouth

There may be more than one reason behind xerostomia; in most patients several factors are present together.

Medicines

The most frequently encountered cause of dry mouth is medication. Antidepressants, antihistamines and blood pressure medicines (particularly diuretics), some painkillers and drugs used to treat urinary incontinence can all reduce salivary flow. The effect may be more pronounced in patients taking several medicines at once.

Systemic conditions

Autoimmune conditions affecting the salivary and tear glands, such as Sjögren's syndrome, poorly controlled diabetes and thyroid disorders may lead to xerostomia. Radiotherapy to the head and neck region and certain chemotherapy protocols can also affect salivary gland function.

Lifestyle and habits

• Mouth breathing: Breathing through the mouth because of nasal congestion, allergy or snoring causes noticeable dryness, especially in the morning.
• Smoking and alcohol: These irritate the mucosa and upset the salivary balance; alcohol-based mouthwashes can have a similar effect.
• Caffeine: A heavy intake of tea, coffee and energy drinks may increase the feeling of dryness.
• Insufficient water intake: Drinking too little water during the day affects the body's fluid balance and, in turn, saliva production.
• Stress and anxiety: Temporary dry mouth is common during periods of intense stress.

What Are the Symptoms?

Dry mouth is not limited to the sensation of "my mouth feels dry". Patients often describe the following complaints:

• A constant sticky feeling, with thick or frothy saliva
• Difficulty speaking and swallowing, and a frequent need to drink water
• A burning, rough or cracked tongue
• Cracking at the corners of the mouth and dry lips
• Changes in the sense of taste
• Persistent bad breath
• Difficulty chewing dry or spicy foods
• Poor denture retention and tenderness of the mucosa in denture wearers

Why Does Dry Mouth Matter?

When the protective duties of saliva diminish, a chain of problems can develop in the mouth:

• Increased risk of decay: Because acid cannot be buffered and minerals cannot be replaced, cavities may progress more quickly, particularly at the necks of the teeth and on root surfaces.
• Gum problems: As plaque accumulates, gum inflammation and bleeding are seen more often. Regular professional scaling is therefore even more important for patients with a dry mouth.
• Bad breath: A rising bacterial load can pave the way for persistent halitosis.
• Fungal infections: Candida-related infections and inflammation at the corners of the mouth occur more frequently in a dry mouth.
• Difficulty for denture and implant patients: With a reduced salivary film, removable dentures move more easily and sore spots may form, while caring for the tissues around implants becomes harder.

Daily Care and Management Suggestions

The aim in managing xerostomia is to support moisture in the mouth throughout the day and to offset the increased risk of decay. The suggestions below are for information only and do not replace a clinical examination:

• Water: Drink regularly in small sips, spread across the day. Keeping water by the bedside can be soothing if you wake at night.
• Sugar-free gum and xylitol: Chewing sugar-free gum can stimulate salivary flow; xylitol-containing products are a safer option where plaque is concerned.
• Moisturising mouthwash: Alcohol-free rinses with moisturising ingredients should be preferred, as alcohol-based products may worsen dryness. You may wish to read our article on everything you need to know about mouthwash.
• Room humidity: Using a humidifier in the bedroom, especially in winter, may help reduce night-time dryness.
• Reducing caffeine and alcohol: Limiting tea, coffee and alcohol, and giving up smoking, supports the health of the mucosa.
• Fluoride: As the risk of decay rises, fluoride toothpaste, gel or varnish may be planned in line with your dentist's advice.
• Diet: Avoiding sugary snacks spread through the day and acidic drinks is particularly important when the mouth is dry.

When Should You See a Clinician?

Dryness that lasts more than a few weeks, interferes with daily life, or is accompanied by a burning tongue, recurrent cavities, bleeding gums or sores in the mouth should always be assessed. The dentist examines the intra-oral findings, determines the risk of decay and draws up a preventive care plan.

If the dry mouth is thought to be linked to an underlying condition or to a medicine you are taking, the relevant medical doctor should be contacted. The most important caution here is this: no prescribed medicine should be stopped, and no dose changed, without consulting the doctor who prescribed it. Any adjustment to treatment is made only after a doctor's assessment. The information in this article is intended for general guidance; a clinical examination is required for individual diagnosis and treatment.

Frequently Asked Questions

Is dry mouth a temporary condition?

Dryness caused by stress, short-term medication or insufficient water intake usually settles once the trigger is removed. Where the cause is long-term medication, Sjögren's syndrome or radiotherapy, dryness may persist and require regular follow-up.

Does a dry mouth really increase the risk of decay?

Yes. Because saliva's buffering, cleansing and remineralising functions are reduced, cavities can progress more rapidly. For this reason more frequent dental check-ups and fluoride support are often recommended.

Which mouthwash should I use for a dry mouth?

The general approach is to prefer alcohol-free products with moisturising ingredients. Which product suits you should be decided together with your dentist, after your intra-oral findings and your risk of decay have been assessed.