Oral parameters in the diagnosis of Sjögren's syndrome.

Xerostomia is the main oral symptom and clinical sign in Sjögren's syndrome (SS) but there are many other causes of a dry mouth. Salivary gland enlargement is a further feature but may be episodic. Xerostomia is a subjective symptom which can be non-invasively assessed by sialometry but this is too variable, insensitive and non-specific to be diagnostic of SS. Sialochemistry, though conceptually appealing is nondiscriminatory and of little diagnostic value. Sialographic changes in SS are not specific and generally regarded as insensitive, though this has recently been questioned. Salivary scintigraphy may be of some value because it is relatively non-invasive and examines all glands simultaneously and over a period of time; but it is non-specific. Lower labial salivary gland biopsy gives more specific diagnostic information than most other investigations but must be carried out and interpreted using strict criteria.