A diagnosis of hyposalivation is based predominantly on the clinical signs and symptoms.[1] There is little correlation between symptoms and objective tests of salivary flow,[18] such as sialometry. This test is simple and noninvasive, and involves measurement of all the saliva a patient can produce during a certain time, achieved by dribbling into a container. Sialometery can yield measures of stimulated salivary flow or unstimulated salivary flow. Stimulated salivary flow rate is calculated using a stimulant such as 10% citric acid dropped onto the tongue, and collection of all the saliva that flows from one of the parotid papillae over five or ten minutes. Unstimulated whole saliva flow rate more closely correlates with symptoms of xerostomia than stimulated salivary flow rate.[1] Sialography involves introduction of radio-opaque dye such as iodine into the duct of a salivary gland.[1] It may show blockage of a duct due to a calculus. Salivary scintiscanning using technetium is rarely used. Other medical imaging that may be involved in the investigation include chest x-ray (to exclude sarcoidosis), ultrasonography and magnetic resonance imaging (to exclude Sjögren's syndrome or neoplasia).[1] A minor salivary gland biopsy, usually taken from the lip,[19] may be carried out if there is a suspicion of organic disease of the salivary glands.[1] Blood tests and urinalysis may be involved to exclude a number of possible causes.[1] To investigate xerophthalmia, the Schirmer test of lacrimal flow may be indicated.[1] Slit-lamp examination may also be carried out.[1]
True hyposalivation may give the following signs and symptoms:
Dental caries (xerostomia related caries) – Without the anticariogenic actions of saliva, tooth decay is a common feature and may progress much more aggressively than it would otherwise ("rampant caries"). It may affect tooth surfaces that are normally spared, e.g., cervical caries and root surface caries. This is often seen in patients who have had radiotherapy involving the major salivary glands, termed radiation-induced caries.[9] Therefore it's important that any products used in managing dry mouth symptoms are sugar-free, as the presence of sugars in the mouth support the growth of oral bacteria, resulting in acid production and development of dental caries [8].&Acid erosion. Saliva acts as a buffer and helps to prevent demineralization of teeth.[10]&Oral candidiasis – A loss of the antimicrobial actions of saliva may also lead to opportunistic infection with Candida species.[9]&Ascending (suppurative) sialadenitis – an infection of the major salivary glands (usually the parotid gland) that may be recurrent.[3] It is associated with hyposalivation, as bacteria are able to enter the ductal system against the diminished flow of saliva.[7] There may be swollen salivary glands even without acute infection, possibly caused by autoimmune involvement.[3]&Dysgeusia – altered taste sensation (e.g., a metallic taste)[1] and dysosmia, altered sense of smell.[3]&Intraoral halitosis[1] – possibly due to increased activity of halitogenic biofilm on the posterior dorsal tongue (although dysgeusia may cause a complaint of nongenuine halitosis in the absence of hyposalivation).&Oral dysesthesia – a burning or tingling sensation in the mouth.[1][3]&Saliva that appears thick or ropey.[9]&Mucosa that appears dry.[9]&A lack of saliva pooling in the floor of the mouth during examination.[1]&Dysphagia – difficulty swallowing and chewing, especially when eating dry foods. Food may stick to the tissues during eating.[9]&The tongue may stick to the palate,[7] causing a clicking noise during speech, or the lips may stick together.[1]&Gloves or a dental mirror may stick to the tissues.[9]&Fissured tongue with atrophy of the filiform papillae and a lobulated, erythematous appearance of the tongue.[1][9]&Saliva cannot be "milked" (expressed) from the parotid duct.[1]&Difficulty wearing dentures, e.g., when swallowing or speaking.[1] There may be generalized mucosal soreness and ulceration of the areas covered by the denture.[3]&Mouth soreness and oral mucositis.[1][3]&Lipstick or food may stick to the teeth.[1]&A need to sip drinks frequently while talking or eating.[3]&Dry, sore, and cracked lips and angles of mouth.[3]&Thirst.[3
However, sometimes the clinical findings do not correlate with the symptoms experienced.[9] E.g., a person with signs of hyposalivation may not complain of xerostomia. Conversely a person who reports experiencing xerostomia may not show signs of reduced salivary secretions (subjective xerostomia).[8] In the latter scenario, there are often other oral symptoms suggestive of oral dysesthesia ("burning mouth syndrome").[3] Some symptoms outside the mouth may occur together with xerostomia.
These include:
Xerophthalmia (dry eyes).[1]&Inability to cry.[1]&Blurred vision.[1]&Photophobia (light intolerance).[1]&Dryness of other mucosae, e.g., nasal, laryngeal, and/or genital.[1]&Burning sensation.[1]&Itching or grittiness.[1]&Dysphonia (voice changes).[1
There may also be other systemic signs and symptoms if there is an underlying cause such as Sjögren's syndrome,[1] for example, joint pain due to associated rheumatoid arthritis.