This condition can result in discomfort, interfere with speech and swallowing, make wearing dentures difficult, cause halitosis Halitosis Halitosis is a frequent or persistent unpleasant breath odor. (See also Evaluation of the Dental Patient.) Halitosis most often results from fermentation of food particles by anaerobic gram-negative... read more , and impair oral hygiene by causing a decrease in oral pH and an increase in bacterial growth. Long-standing xerostomia can result in severe tooth decay Caries Caries is tooth decay, commonly called cavities. The symptoms—tender, painful teeth—appear late. Diagnosis is based on inspection, probing of the enamel surface with a fine metal instrument... read more and oral candidiasis Candidiasis (Mucocutaneous) Candidiasis is skin and mucous membrane infection with Candida species, most commonly Candida albicans. Infections can occur anywhere and are most common in skinfolds, digital web spaces, genitals... read more . Xerostomia is a common complaint among older adults, affecting about 20% of them.
(See also Introduction to the Approach to the Dental Patient Introduction to the Approach to the Dental Patient A physician should always examine the mouth and be able to recognize major oral disorders, particularly possible oral cancers. However, consultation with a dentist is needed to evaluate patients... read more .)
Pathophysiology of Xerostomia
Stimulation of the oral mucosa signals the salivatory nuclei in the medulla, triggering an efferent response. The efferent nerve impulses release acetylcholine at salivary gland nerve terminals, activating muscarinic receptors (M3), which increase saliva production and flow. Medullary signals responsible for salivation may also be modulated by cortical inputs from other stimuli (eg, taste, smell, anxiety).
Etiology of Xerostomia
Xerostomia is usually caused by the following:
Radiation to the head and neck (for cancer treatment)
Systemic disorders are less commonly the cause, but xerostomia is common in Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a relatively common chronic, autoimmune, systemic, inflammatory disorder of unknown cause. It is characterized by dryness of the mouth, eyes, and other mucous membranes due... read more and may occur in HIV/AIDS Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection results from 1 of 2 similar retroviruses (HIV-1 and HIV-2) that destroy CD4+ lymphocytes and impair cell-mediated immunity, increasing risk of certain... read more , uncontrolled diabetes Diabetes Mellitus (DM) Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more , and certain other disorders.
Drugs are the most common cause (see table Some Causes of Xerostomia Some Causes of Xerostomia Xerostomia is dry mouth caused by reduced or absent flow of saliva. This condition can result in discomfort, interfere with speech and swallowing, make wearing dentures difficult, cause halitosis... read more ); about 400 prescription drugs and many over-the-counter (OTC) drugs cause decreased salivation. The most common include the following:
Chemotherapy drugs Systemic Cancer Therapy Systemic cancer therapy includes chemotherapy (ie, conventional or cytotoxic chemotherapy), hormone therapy, targeted therapy, and immune therapy (see also Overview of Cancer Therapy). The number... read more cause severe dryness and stomatitis Stomatitis Oral inflammation and ulcers, known as stomatitis, may be mild and localized or severe and widespread. They are invariably painful. (See also Evaluation of the Dental Patient and Gingivitis... read more while they are being taken; these problems usually end after therapy is stopped.
Other common drug classes that cause xerostomia include antihypertensives Drugs for Hypertension A number of drug classes are effective for initial and subsequent management of hypertension: Adrenergic modifiers Angiotensin-converting enzyme (ACE) inhibitors Angiotensin II receptor blockers... read more , anxiolytics Anxiolytics and Sedatives Anxiolytics and sedatives include benzodiazepines, barbiturates, and related drugs. High doses can cause stupor and respiratory depression, which is managed with intubation and mechanical ventilation... read more , and antidepressants Drug Treatment of Depression Several drug classes and drugs can be used to treat depression: Selective serotonin reuptake inhibitors (SSRIs) Serotonin modulators (5-HT2 blockers) Serotonin-norepinephrine reuptake inhibitors... read more (less severe with selective serotonin reuptake inhibitors [SSRIs] than with tricyclics).
The rise of illicit methamphetamine Amphetamines Amphetamines are sympathomimetic drugs with central nervous system stimulant and euphoriant properties whose toxic adverse effects include delirium, hypertension, seizures, and hyperthermia... read more use has resulted in an increasing incidence of meth mouth, which is severe tooth decay and periodontal inflammation Periodontitis Periodontitis is a chronic inflammatory oral disease that progressively destroys the tooth-supporting apparatus. It usually manifests as a worsening of gingivitis and then, if untreated, with... read more caused by methamphetamine-induced xerostomia. The damage is exacerbated by the bruxing Bruxism Bruxism is clenching or grinding of teeth. Bruxism can abrade and eventually wear down enamel and dentin in the crowns of teeth, damage metal or ceramic dental crowns, and cause teeth to become... read more and clenching caused by the drug along with elevated intake of sugary beverages and poor oral hygiene while under the influence of the drug. This combination causes very rapid destruction of teeth.
Incidental radiation to the salivary glands during radiation therapy for head and neck cancer often causes severe xerostomia (5200 cGy causes severe, permanent dryness, but even low doses can cause temporary drying).
Evaluation of Xerostomia
History of present illness should include acuity of onset, temporal patterns (eg, constant vs intermittent, presence only on awakening), provoking factors, including situational or psychogenic factors (eg, whether xerostomia occurs only during periods of psychologic stress or certain activities), assessment of fluid status (eg, fluid intake habits, recurrent vomiting or diarrhea), and sleeping habits. A history of use of recreational drugs should be taken.
Review of systems should seek symptoms of causative disorders, including dry eyes, dry skin, rashes, and joint pain (Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a relatively common chronic, autoimmune, systemic, inflammatory disorder of unknown cause. It is characterized by dryness of the mouth, eyes, and other mucous membranes due... read more ).
Past medical history should inquire about conditions associated with xerostomia, including Sjögren syndrome, history of radiation treatment, head and neck trauma, and a diagnosis of or risk factors for HIV infection Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection results from 1 of 2 similar retroviruses (HIV-1 and HIV-2) that destroy CD4+ lymphocytes and impair cell-mediated immunity, increasing risk of certain... read more . Drug profiles should be reviewed for potential offending drugs (see table Some Causes of Xerostomia Some Causes of Xerostomia Xerostomia is dry mouth caused by reduced or absent flow of saliva. This condition can result in discomfort, interfere with speech and swallowing, make wearing dentures difficult, cause halitosis... read more ).
Physical examination is focused on the oral cavity, specifically any apparent dryness (eg, whether the mucosa is dry, sticky, or moist; whether saliva is foamy, thick, stringy, or normal in appearance), the presence of any lesions caused by Candida albicans, and the condition of the teeth.
The presence and severity of xerostomia can be assessed in several ways. For example, a tongue blade can be held against the buccal mucosa for 10 seconds. If the tongue blade falls off immediately when released, salivary flow is considered normal. The more difficulty encountered removing the tongue blade, the more severe the xerostomia. In women, the lipstick sign, where lipstick adheres to the front teeth, may be a useful indicator of xerostomia.
If there appears to be dryness, the submandibular, sublingual, and parotid glands should be palpated while observing the ductal openings for saliva flow. The openings are at the base of the tongue anteriorly for the submandibular and sublingual glands and on the middle of the inside of the cheek for the parotid glands. Drying the duct openings with a gauze square before palpation aids observation. If a graduated container is available, the patient can expectorate once to empty the mouth and then expectorate all saliva into the container. Normal production is 0.3 to 0.4 mL/min. Significant xerostomia is 0.1 mL/min.
Dental caries Caries Caries is tooth decay, commonly called cavities. The symptoms—tender, painful teeth—appear late. Diagnosis is based on inspection, probing of the enamel surface with a fine metal instrument... read more may be observed at the margins of restorations or in unusual places (eg, at the gum line, incisal edges, or cusp tips of the teeth).
A common manifestation of C. albicans infection is areas of erythema and atrophy (eg, loss of papillae on the dorsum of the tongue). Less common is the better-known white, cheesy curd that bleeds when wiped off.
The following findings are of particular concern:
Extensive tooth decay
Concomitant dry eyes, dry skin, rash, or joint pain
Risk factors for HIV
Interpretation of findings
Xerostomia is diagnosed by symptoms, appearance, and absence of salivary flow when massaging the salivary glands.
No further assessment is required when xerostomia occurs after initiation of a new drug and stops after cessation of that drug or when symptoms appear within several weeks of irradiation of the head and neck. Xerostomia that occurs with abrupt onset after head and neck trauma may be caused by nerve damage.
Concomitant presence of dry eyes, dry skin, rash, or joint pain, particularly in a female patient, suggests a diagnosis of Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a relatively common chronic, autoimmune, systemic, inflammatory disorder of unknown cause. It is characterized by dryness of the mouth, eyes, and other mucous membranes due... read more . Severe tooth discoloration and decay, out of proportion to expected findings, may be indicative of illicit drug use, particularly methamphetamines Amphetamines Amphetamines are sympathomimetic drugs with central nervous system stimulant and euphoriant properties whose toxic adverse effects include delirium, hypertension, seizures, and hyperthermia... read more . Xerostomia that occurs only during nighttime or that is noted only on awakening may be indicative of excessive mouth breathing in a dry environment.
Salivary gland biopsy
For patients in whom the presence of xerostomia is unclear, sialometry can be conducted by placing collection devices over the major duct orifices and then stimulating salivary production with citric acid or by chewing paraffin. Normal parotid flow is 0.4 to 1.5 mL/min/gland. Flow monitoring can also help determine response to therapy.
The cause of xerostomia is often apparent, but if the etiology is unclear and systemic disease is considered possible, further assessment should be pursued with biopsy of a minor salivary gland (for detection of Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a relatively common chronic, autoimmune, systemic, inflammatory disorder of unknown cause. It is characterized by dryness of the mouth, eyes, and other mucous membranes due... read more , sarcoidosis Sarcoidosis Sarcoidosis is an inflammatory disorder resulting in noncaseating granulomas in one or more organs and tissues; etiology is unknown. The lungs and lymphatic system are most often affected, but... read more , amyloidosis Amyloidosis Amyloidosis is any of a group of disparate conditions characterized by extracellular deposition of insoluble fibrils composed of misaggregated proteins. These proteins may accumulate locally... read more , tuberculosis Tuberculosis (TB) Tuberculosis (TB) is a chronic, progressive mycobacterial infection, often with a period of latency following initial infection. TB most commonly affects the lungs. Symptoms include productive... read more , or cancer Overview of Cancer Cancer is an unregulated proliferation of cells. Its prominent properties are A lack of differentiation of cells Local invasion of adjoining tissue Metastasis, which is spread to distant sites... read more ) and HIV testing Diagnostic tests Human immunodeficiency virus (HIV) infection results from 1 of 2 similar retroviruses (HIV-1 and HIV-2) that destroy CD4+ lymphocytes and impair cell-mediated immunity, increasing risk of certain... read more . The lower lip is a convenient site for biopsy.
Treatment of Xerostomia
Cause treated and causative drugs stopped when possible
Regular oral hygiene and dental care to prevent tooth decay
When possible, the cause of xerostomia should be addressed and treated.
For patients with drug-related xerostomia whose therapy cannot be changed to another drug, drug schedules should be modified to achieve maximum drug effect during the day because nighttime xerostomia is more likely to cause caries. Custom-fitted acrylic night guards carrying fluoride gel may also help limit caries in these patients. For all drugs, easy-to-take formulations, such as liquids, should be considered, and sublingual dosage forms should be avoided. The mouth and throat should be lubricated with water before swallowing capsules and tablets or before using sublingual nitroglycerin. Patients should avoid decongestants and antihistamines.
Patients using continuous positive airway pressure for obstructive sleep apnea Continuous positive airway pressure (CPAP) Obstructive sleep apnea (OSA) consists of episodes of partial or complete closure of the upper airway that occur during sleep and lead to breathing cessation (defined as a period of apnea or... read more may benefit from using the humidifier function of the device. Patients using oral appliance therapy may benefit from a room humidifier.
Symptomatic treatment consists of measures that do the following:
Increase existing saliva
Replace lost secretions
Drugs that augment saliva production include cevimeline and pilocarpine, both cholinergic agonists. Cevimeline (30 mg orally 3 times a day) has less M2 (cardiac) receptor activity than pilocarpine and a longer half-life. The main adverse effect is nausea. Pilocarpine (5 mg orally 3 times a day) may be given after ophthalmologic and cardiorespiratory contraindications are excluded; adverse effects include sweating, flushing, and polyuria.
Sipping sugarless fluids frequently, chewing xylitol-containing gum, and using an over-the-counter saliva substitute containing carboxymethylcellulose, hydroxyethylcellulose, or glycerin may help. Petroleum jelly can be applied to the lips and under dentures to relieve drying, cracking, soreness, and mucosal trauma. A cold-air humidifier may aid mouth breathers who typically have their worst symptoms at night.
Meticulous oral hygiene is essential. Patients should brush and floss regularly (including just before bedtime) and use fluoride rinses or gels daily; using newer toothpastes with added calcium and phosphates also may help avoid rampant caries. An increased frequency of preventive dental visits with plaque removal is advised. The most effective way to prevent caries is to sleep with individually fitted carriers containing 1.1% sodium fluoride or 0.4% stannous fluoride. In addition, a dentist can apply a 5% sodium fluoride varnish 2 to 4 times a year.
Patients should avoid sugary or acidic foods and beverages and any irritating foods that are dry, spicy, astringent, or excessively hot or cold. It is particularly important to avoid ingesting sugar near bedtime.
Although xerostomia becomes more common among older patients, this is probably due to the many drugs typically used by those patients rather than aging itself.
Drugs are the most common cause, but systemic diseases (most commonly Sjögren syndrome or HIV) and radiation therapy also can cause xerostomia.
Symptomatic treatment includes increasing existing saliva flow with stimulants or drugs, and artificial saliva replacement; xylitol-containing gum and sugarless candy may be useful.
Patients with xerostomia are at high risk of tooth decay; meticulous oral hygiene, additional preventive measures in home care, and professionally applied fluorides are essential.