Salivary Gland Disorders

Saliva is essential for speech and swallowing and plays an important role in maintaining oral health by maintaining the integrity of the oral mucosa. It contains a variety of proteins with anti-bacterial activity and salts and minerals including fluoride and acts as a buffer and is, therefore, important in the control of dental caries and periodontal disease.

Saliva is produced by the three pairs of major salivary glands which are the parotid glands in the preauricular region, the submandibular glands and the sublingual glands in the floor of the mouth. In addition, there are about 200 minor salivary glands distributed widely just below the mucosal lining of the mouth and on the hard and soft palate, cheeks, lips and floor of mouth.

Salivary glands can be involved in many pathological processes, including congenital abnormalities, infections and other inflammatory disorders, obstruction, neoplasia and degenerative disorders. The most frequent problems seen in clinical practice are due to infections, obstruction from stones, benign and malignant tumours and destructive auto-immune disease.

Infections - The mumps virus is the most frequent cause of salivary gland infection. Bacterial infection of the major glands usually arises from the mouth and is often a recurrent problem especially in a gland previously damaged by stones or irradiation or in debilitated patients. With the extended survival of HIV positive patients receiving triple chemotherapy an increasing variety of salivary gland disorders are being seen. A specialist knowledge of dental and oral diseases is necessary for the proper management of these patients.

Obstruction - Calculi or stones can form in the major salivary glands and their ducts, in a manner directly analogous to the gal bladder and bile ducts and the kidney and ureters. They cause obstruction of salivary outflow typically with pain and swelling at meal times. If the obstruction is not relieved the gland becomes damaged and often requires an operation to remove the gland. Obstruction of minor salivary glands also occurs resulting in cyst like swellings in the lips and cheeks.

Tumours - A very large variety of both benign and malignant tumours can involve any of the major or minor salivary glands. Although the majority are benign they grow relentlessly to reach grotesque proportions. Malignant tumours of the salivary glands account for 2% of all cancers. The management of salivary gland tumours requires specialised surgical skills due to the proximity of important cranial nerves and the often aggressive nature of the disease. Often patients will require a combination of surgery and radiotherapy to control their disease and should be managed on multi-disciplinary clinics.

Degenerative Disease - The salivary and lacrimal glands are subject to an auto-immune destructive condition (Sjögren's syndrome) which results in dry eyes and a dry mouth. Sjögren's syndrome is often accompanied by other systemic diseases such as rheumatoid arthritis, systemic lupus erythematosis or primary biliary sclerosis. Patients develop severe oral symptoms relating to failure of salivary production and approximately 10% of patients with Sjögren's syndrome will develop a non-Hodgkin's lymphoma. These patients require meticulous follow-up in order to detect the onset of lymphoma at an early stage when treatment is still effective.