Dry Mouth

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Lead Editors - Wendy Walker and Tarina van der Stockt

Introduction

The medical term for dry mouth is Xerostomia, which is described as being "the subjective feeling of oral dryness, which is often (but not always) associated with hypofunction of the salivary glands".

Signs & Symptoms

• sensation of dryness/stickiness in the mouth

• burning sensation in the mouth

• tongue “sticking” causing difficulty in speaking

• difficulty moving food in mouth when eating, especially dry food such as bread

• increased sores/mouth ulcers
  
• dry, sore and cracked lips

Anatomy

This image shows the 3 main salivary glands.

The Sublingual and Submandibular glands are supplied by the Facial Nerve (7th Cranial Nerve); the Parotid gland is supplied by the Glossopharyngeal Nerve (9th Cranial Nerve).

In addition to these 3, there are more than 800 minor salivary glands spread out throughout the oral mucosa. These minor gsalivary glands are supplied by the Facial Nerve.

It is worth noting that in the region of 65-70% of saliva in the mouth is produced by the submandibular glands, even though as you can clearly see in the image, they are much smaller than the parotid glands.

Causes

1. Age: dry mouth becomes more common with age
2. Facial Palsy: in cases of facial palsy, dry mouth can occur as two of the three main salivary glands receive their parasympathetic nerve supply from the facial nerve: the sublingual and glossopharyngeal glands. (The parotid gland is not innervated by the facial nerve, so is unaffected.)
3. Medications: some commonly prescribed medications (particularly those used for control of high blood pressure and treatment of depression)can cause dry mouth, so check the information leaflet to see if this is one of the side effects
4. Medical conditions: there are a number of medical conditions which cause dry mouth, with diabetes, and Sjorgren’s Syndrome being two of the most common