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Xerostomia is dry mouth. Many patients notice that their mouth is dry; others may not be conscious of it but carry water bottles to constantly sip from. Most patients with xerostomia have definite signs of reduced salivary flow (eg, dry and sticky mucosa, foamy or stringy saliva). Xerostomia interferes with speech and swallowing, causes fetid breath, and, because the reduced salivary flow no longer washes away bacteria, impairs oral hygiene. In long-standing xerostomia, tooth decay can be severe. Caries may develop at the margins of restorations or in unusual places (eg, at the neck or tip of the tooth). Candida albicans infection is common, producing either erythema and atrophy of the dorsum of the tongue or a white, cheesy curd that bleeds when wiped off.
Etiology
Xerostomia is usually caused by medical treatment but sometimes results from disease processes or aging.
Xerostomia is most often due to drugs, most commonly anticholinergics (including drugs for motion sickness, anxiolytics, antihistamines, antidepressants, antipsychotics, and decongestants), antiparkinsonians, and, to a lesser degree, opioids, particularly meperidine . Severe xerostomia can follow radiation to the salivary glands during treatment for head and neck cancer (5200 cGy causes severe, permanent dryness, but even low doses can cause temporary drying).
Xerostomia is common in Sjögren's syndrome and occasionally occurs in sarcoidosis, amyloidosis, and HIV infection. Less commonly, salivary gland involvement in TB or leprosy results in xerostomia. Temporary drying may also be caused by viral infections, dehydration, and fear.
Evaluation
Diagnosis is based on symptoms, appearance, and absence of salivary flow when massaging the salivary glands. Cause is often apparent, but if sarcoid is considered possible, biopsy of a labial salivary gland is recommended.
Salivary flow rates can be measured to monitor therapy. Saliva is stimulated with citric acid or by chewing paraffin and is collected by devices placed over the major duct orifices. Normal parotid flow is 0.4 to 1.5 mL/min/gland. Diagnosis may be achieved easily by holding a tongue blade against the buccal mucosa for 5 sec. If the tongue blade falls off when released, then salivary flow is normal. The more difficult it is to remove the tongue blade, the more severe the xerostomia.
Treatment
Patients with xerostomia and functional salivary gland tissue should avoid decongestants and antihistamines and maintain meticulous oral hygiene (including application of fluoride rinses or gels). Sipping sugarless fluids frequently, chewing xylitol-containing gum, and using a saliva substitute containing carboxymethylcellulose or hydroxyethylcellulose may help.
Drug therapy includes cevimeline or pilocarpine , both cholinergic agonists. Cevimeline (30 mg po tid) has less M2 (cardiac) receptor activity than pilocarpine and a longer half-life. The main adverse effect is nausea. Pilocarpine (5 mg po tid) may be given after ophthalmologic and cardiorespiratory contraindications are excluded; adverse effects include sweating, flushing, and polyuria.
If drugs that cause xerostomia are given before bedtime, xerostomia occurring during sleep may seem less troubling but is more likely to lead to caries than is daytime xerostomia. A few drops of water should be sipped before taking nitroglycerin , because xerostomia may prevent the dissolution. The most effective way to prevent caries is to sleep with individually fitted carriers containing 1.1% fluoride. If 2 carriers cannot be worn at once, then each arch should be covered every other night.
Last full review/revision November 2005
Content last modified November 2005
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