Xerostomia is defined as a subjective complaint of dry mouth that may result from a decrease in the production of saliva (Guggenheimer J, Moore PA, 2003).
It is a relatively common complaint, affecting approximately 10% of the general population (Fox RI, 2006). The prevalence rises both as the number of prescription medications taken increases and with the number of medical conditions present (Nederfors T, 2000). Indeed, reports suggest that up to 25% of people over 65 years of age suffer from dry mouth, rising to 50% among the institutionalised elderly (Astor FC et al, 1999; Hochberg MC et al, 1998; Nederfors T et al, 1997; Ikebe K et al, 2001). While many cases of dry mouth are drug related, as over 400 commonly used drugs are known to be xerogenic (Guggenheimer J, Moore PA, 2003; Field EA et al, 2001), the aetiology may be multi-factorial.
Saliva components and function
Saliva is the viscous, clear, watery fluid secreted by the parotid, submandibular, sublingual and minor salivary glands. Saliva contains two major types of protein secretions: a serous secretion containing the digestive enzyme ptyalin and a mucous secretion containing the lubricating aid mucin. Other important constituents of saliva include potassium, bicarbonate, sodium and chloride ions, and antimicrobial agents including thiocyanate, lysozyme, immunoglobulins, lactoferrin and transferrin. The buffering, cleansing, lubricating and antimicrobial activities of saliva play a vital role in maintaining oro-dental health.
Signs and symptoms of xerostomia
While dry mouth may seem more like a nuisance than a serious medical condition, it can have a significant deleterious impact on the patient’s quality of life, affecting their dietary habits, nutritional status, speech, swallowing, tolerance and retention of dental prostheses. Susceptibility to caries and periodontal disease is also greatly increased.
Patients with xerostomia often complain of taste disorders (oral dysgeusia), a painful, burning tongue (glossodynia), persistent sore throat, hoarseness, dry nasal passages and an increased need to drink water, especially at night. Dry foods, such as cereals and biscuits, may be particularly difficult to chew and swallow. Patients may also experience difficulty in swallowing oral medication. Xerostomia can lead to parotid gland enlargement, sialadenitis, cheilitis, inflammation or ulceration of the tongue and buccal mucosa, halitosis, and oral candidiasis.
Diagnosis of xerostomia
Xerostomia should be considered if the patient complains of dry mouth or difficulty eating dry foods.
On examination, the mucosa appears red, shiny and dry, and a mirror or gloved finger may stick to the buccal mucosa or tongue. There may be little or no pooled saliva in the floor of the mouth, and the tongue is dry, fissured or cobble-stoned, with atrophy of the papillae (Figure 1). The saliva may appear stringy, ropy or foamy. Patients may present with caries affecting the cervical margins, anterior incisal edges and cusps of the posterior teeth (Figure 2), while fungal infections such as angular cheilitis and pseudomembranous candidiasis may add to the discomfort.
The diagnosis is generally based on the history, clinical examination and routine sialometry (measurement of salivary flow). The normal flow rate for unstimulated, whole saliva is 0.3 to 0.5 mL/min; for stimulated saliva, 1 to 2 mL/min. Unstimulated flow rate of 0.1 mL/min and stimulated flow rate of 0.7 mL/min are considered xerostomic (Navazesh M, 2003).
Additional investigations, including sialography, scintigraphy, microbial, serologic and histologic tests, generally require specialist input. Patients with ‘false xerostomia’ – a sensation of dryness despite normal salivary output – may benefit from specialist care.
Management of xerostomia
Management includes the identification and treatment of any underlying cause, reviewing current medication and increasing existing salivary flow using salivary stimulants (sialagogues), as well as measures aimed at caries control and treatment of infections.
Patients should be advised to take frequent sips of water throughout the day, avoid dry, spicy, astringent or sugary foods, and reduce their intake of tobacco, alcohol and caffeine.
While regular dental check-ups are essential, patients must be encouraged to play an active role in managing their xerostomia by increasing oral hygiene efforts using a soft toothbrush and a mild, low-abrasive fluoride toothpaste.
It is recommended that commonly used oral care products (toothpastes, mouthwashes, etc) that contain alcohol and detergents are replaced by those that do not contain these elements and which use a natural salivary enzyme antibacterial protection system instead. Use of oral agents in gel form at night protects the oro-dental tissues during sleep.
Daily fluoride application is essential and may be delivered via a mouthrinse, custom-made tray or high fluoride toothpaste. Chlorhexidine rinses help to reduce caries by lowering lactobacillus counts in the mouth. Saliva stimulants such as chewing gum may stimulate saliva flow when functional salivary tissue remains. While pharmacological sialagogues may be beneficial (e.g. pilocarpine), the side effects are generally unacceptable; over the counter products therefore provide the mainstay of treatment, providing symptomatic relief and protection against the effects of dry mouth.
Xerostomia is a common problem that, if not recognised and treated, can clearly have a major effect on a patient’s quality of life.
Improved education, awareness of this condition and instigation of appropriate treatment can significantly reduce the morbidity associated with this distressing condition and the deleterious long-term impact of xerostomia on dental health.
Astor FC, Hanft KL, Ciocon JO (1999) Xerostomia: a prevalent condition in the elderly. ENT-Ear, Nose Throat J 78: 476-9
Field EA, Fear S, Higham SM et al (2001) Age and medication are significant risk factors for xerostomia in an English population attending general dental practice. Gerodontology 18(1): 21-4
Fox RI (2006) Dry mouth and salivary gland dysfunction. (Interactive textbook – Chapter 27). Downloaded from: symptomresearch. nih.gov/chapter_27/sec2/ cpfs2pg1.html
Guggenheimer J, Moore PA (2003) Xerostomia. Etiology, recognition and treatment. JADA 134: 61-9
Hochberg MC, Tielsch J, Munoz B et al (1998) Prevalence of symptoms of dry mouth and their relationship to saliva production in community dwelling elderly: the SEE project. J Rheumatol 25: 486-91
Ikebe K, Nokubi T, Sajima H et al (2001) Perception of dry mouth in a sample of community-dwelling older adults in Japan. Spec Care Dentist 21(2): 52-9
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Nederfors T (2000) Xerostomia and hyposalivation. Adv Dent Res 14: 48-56.
Nederfors T, Isaksson R, Mornstad H, Dahlof C (1997) Prevalence of perceived symptoms of dry mouth in an adult Swedish population – relation to age, sex and pharmacotherapy. Community Dent Oral Epidemiol 25: 211-6