Dry Mouth

Reduced saliva flow that results in a dry mouth is a common problem among older adults. It is caused by certain medical disorders and is often a side effect of medications such as antihistamines, decongestants, pain killers and diuretics.

Some of the common problems associated with dry mouth include a constant sore throat, burning sensation, problems speaking, difficulty swallowing, hoarseness or dry nasal passages. Left untreated, dry mouth can damage your teeth. Without adequate saliva to lubricate your mouth, wash away food, and neutralize the acids produced by plaque, extensive decay can occur.

Your dentist can recommend various methods to restore moisture. Sugar-free candy or gum stimulates saliva flow, and moisture can be replaced by using artificial saliva and oral rinses.

In ancient times, long before the invention of oral care devices and medications, nature provided humans a unique and effective means for protecting the hard and soft tissues of the mouth. Without this protection, the teeth and supporting tissues would soon fall prey to the billions of microorganisms that thrive in the oral environment. This protective mechanism is a fluid we call saliva. After millions of years of human evolution it remains one of the most important secretions produced by the human body, with health benefits extending far beyond the oral cavity.

Saliva is not simply water. Far from it. Saliva is a complex fluid produced and secreted by three pairs of major salivary glands - parotid, submandibular and sublingual - as well as by many minor salivary glands scattered throughout the oral cavity. The combined product of these glands is usually referred to as whole saliva, and it is composed of electrolytes, proteins, lipids, enzymes, and small organic molecules. An additional component of pooled saliva, the gingival fluid, is not a true form of saliva yet contributes to the fluid volume. The major functional roles of saliva include digestion, lubrication, and protection. specifically, it clears food from the mouth; helps neutralize the pH of plaque after eating; forms a protective diffusion barrier on enamel to aid in the prevention of tooth decay; and acts as an ion reservoir to aid in remineralization. Saliva possesses antimicrobial mechanisms to help control oral microrganisms, and as a lubricant, saliva is vital for swallowing and speech, as well as allowing smooth air flow during breathing. It protects the oral mucosa as a buffer against various mechanical, thermal and chemical irritations; assists in the digestion of starchy foods; and facilitates in taste. As a diagnostic tool, saliva is being increasingly used as an indicator of systemic diseases.

In brief, this remarkable fluid is a vital component of good health and overall quality of life. For many people, including many health care professionals, the presence of saliva is simply taken for granted...until it is missing or significantly reduced. Only then does its importance become dramatically obvious.

Unfortunately, for millions of people the dire consequences of inadequate saliva are a reality. Dry Mouth, or xerostomia, is an oral dryness caused by a lack of normal salivary secretion, either a reduction in salivary flow or alteration of salivary composition. Clinically, the manifestations of salivary gland dysfunction can range from xerostomia, or dry mouth, to mild hypofunction with the presence of minimal saliva. The duration of these effects can range from permanent alteration in salivary function to a transient change, dependent on the amount of salivary gland damage or degree of involvement.

Due to the variation of salivary flow rates from person to person, the point at which a person complains of dry mouth is quite subjective. On average, when unstimulated whole saliva decreases to about half of its normal value, individuals complain of oral dryness. for this to occur, more than one gland must be affected. In many cases the effects on oral health and quality of life can be devastating.

There are many causes of decreased salivary gland function. the most common causes of oral dryness include medical therapies and systemic disorders. Loss of water and metabolites results in dehydration which can lead to a decrease in salivary flow and thus, xerostomia. Dehydration may be due to insufficient water intake; loss of water through the skin due to fever, excessive sweating or burns; loss of blood; diarrhea; renal insufficiency and subsequent water loss due to diabetes insipidus or diabetes mellitus; or protein malnutrition.

The medical therapies that interfere with salivary function are dominated by radiotherapy to the head and neck, drugs, and surgical and traumatic etiologies. Damage to the salivary glands with resultant xerostomia can be caused by radiation therapy to the head and neck region, including the salivary glands. Radiation-induced xerostomia is usually permanent when bilateral radiation treatment of the salivary glands cannot be avoided. One study found that the resting flow rate of parotid saliva was reduced fifty percent, twenty- four hours after the administration of only two-hundred-twenty-five CGY of radiation. After six weeks of treatment using two GY per fraction, for a total dose of six thousand CGY, the reduction was more than seventy-five percent. another study found that there was a progressive decrease in salivary flow following radiation therapy, throughout the three-year course of the study. If possible, clinicians should make every effort to minimize exposure of the major salivary glands during radiation therapy. In addition, patients scheduled for therapeutic irradiation should be referred to a dentist for needed dental treatment prior to initiating irradiation.

Xerostomia can also result from systemic diseases, most commonly Sjogren's Syndrome. Sjogren's Syndrome affects salivary and lacrimal functions as well as connective tissue, and following rheumatoid arthritis, is the most common autoimmune rheumatic disease. It may occur in a primary form in the absence of other diseases, or in a secondary form as a complication of other autoimmune rheumatic disorders such as rheumatoid arthritis, systemic lupus erythematosus, or scleroderma. Sjogren's Syndrome most often is diagnosed in women over forty years of age. Xerostomia is found in greater than ninety percent of Sjogren's Syndrome patients. Other systemic disorders such as graft-versus-host-disease and the diffuse infiltrative Lymphocytosis Syndrome, secondary to HIV infection, may also result in xerostomia. Additional systemic disorders that can cause dry mouth include sarcoidosis, amyloidosis, type five hyperlipidemia, and the Eosinophilia-Myalgia Syndrome.

Interference with neural transmission affecting the salivary glands can result from certain medications; autonomic dysfunction; CNS conditions such as Alzheimer's disease; trauma; or a decrease in mastication resulting in salivary gland atrophy. Hypoplasia of the parotid glands has been reported in patients with Melkersson-Rosenthal Syndrome, a rare disease which classically produces a fissured tongue, salivary gland hypofunction and facial hemiparesis. Dry mouth, a sore and bald tongue, and angular stomatitis are common findings in Plummer-Vinson Syndrome.

Many medications, prescription and OTC, can cause xerostomia through their anticholinergic or antiadrenergic properties, and clinicians must be aware that combinations of certain drugs may heighten this effect. In fact, it is estimated that there are more than four hundred drugs that have the capacity to cause oral dryness. A smaller number of drugs have been shown to actually induce salivary gland hypofunction. Commonly used medications with a high potential for causing xerostomia include tricyclic antidepressants; antihistamines; benzodiazepines; phenothiazine derivatives; and antiparkinson medications. Other drugs that can cause dry mouth include narcotic analgesics; appetite suppressants; anticholinergics and anti-spasmodics; antiemetics and antidiarrheals; antihypertensives, especially diuretics; and psychotropic agents. Xerostomia may also be considered a manifestation of anxiety or depression, even in the absence of medication use.

Contrary to popular belief, xerostomia is not a natural consequence of the aging process. Studies have shown that changes in salivary gland function as people age are modest changes, and not all salivary glands are affected. The clinical impact of aging on salivary gland output is not considered to be significant. If the elderly appear to be more affected by xerostomia, the cause is likely related to an increased usage of xerostomia-inducing medications or a higher incidence of certain systemic disorders that may cause xerostomia.

There are a number of clinical signs and oral complications associated with xerostomia. Oral sequelae may include foamy, viscous or ropy saliva; dry, cracked lips; burning, fissured or lobulated tongue; dry, pale cheeks; swollen and/or painful salivary glands; frequent thirst; difficulty chewing; difficulty swallowing, or dysphagia; speech difficulty, or dysphonia; and impaired taste. Another manifestation can include an increased incidence of oral infections such as candidiasis, which is a common finding in individuals with xerostomia, and may have an indolent presentation called chronic erythematous candidiasis. Rampant tooth decay may result from the absence or decrease in the cleansing and remineralization benefits of saliva, with attendant increase in the concentration and activity of acidogenic oral organisms and a reduction in the clearance of sugars from the oral cavity.

Generalized exocrine hypofunction may also cause symptoms of dryness in anatomic locations other than the mouth. These complications include dryness of the throat; difficulty speaking; hoarseness; dryness of the nasal mucosa; impaired olfactory function; dryness of the eyes, or xeropthalmia, with burning and/or itching and blurred vision or light sensitivity; dryness of the skin, or xeroderma; constipation; and dryness, burning and/or itching of the vagina.

It is obvious that xerostomia is not an isolated symptom. In fact, one study states that patients with xerostomia complain on average of approximately three other symptoms. When xerostomia is chronic, the oral and systemic complications can be serious and debilitating. These may include not only recurrent oral candidiasis and accelerated caries, but also sleep disruption; fibromyalgia; weight loss; malnutrition; sialolithiasis; and bacterial sialadenitis. Not surprisingly, each of the complications associated with xerostomia requires attention in terms of diagnosis, treatment and management, which is one reason why a multi-disciplinary team approach to treating xerostomia is so important. This includes accurate diagnosis of both the etiology and the degree of salivary hypofunction.

Certain tests can be performed to assist in determining the etiology of salivary dysfunction. these include tests for dry eyes; blood tests to help determine the presence of an autoimmune disorder; imaging tests such as isotope scans to study the metabolic status of the major salivary glands; salivary scintigraphy to assess glandular function; special salivary tests to detect the presence of antibodies associated with autoimmune disorders; and evaluation of depression and other psychological disorders. The simplest test, and a very significant one, is sialometry, which measures the flow rate of saliva. Unstimulated whole saliva can be collected for a specified time and measured in terms of milliliters or grams per minute. In contrast, stimulated whole saliva can be collected for an equal length of time by chewing paraffin wax or placement of a two percent citric acid solution on the tongue to stimulate flow. In general, patients whose unstimulated flow rate is less than or equal to zero-point-one milliliter per minute, and whose stimulated flow rate is less than or equal to zero-point-five milliliter per minute, should be evaluated for xerostomia-inducing disorders. However, because of the differences in individuals and a very large "normal" range, these parameters must not be used rigidly.

Many experts have observed that the visual condition of the oral mucosa often does not correlate to the subjective feeling of the patient. Many patients who appear to have a moist mouth complain of severe dry mouth, while others who appear dry may not complain at all. Some experts suggest that baseline unstimulated and stimulated whole saliva flow rates should be obtained for all patients, particularly in the dental office setting, so that volume changes can be evaluated more objectively. Well established methods are also available to measure the function of the salivary glands individually.

Treatment of xerostomia consists of therapeutic modalities designed to eliminate the cause of the condition, or if this is impractical, to provide preventive palliative treatment designed to provide relief of the symptoms. It is important to provide treatment for the various sequelae that may develop as a result of dry mouth. Regarding primary treatment for xerostomia itself, stimulation of salivary flow through pharmacologic, mechanical or other means will provide the most efficacious relief of symptoms and the best chance to avoid future complications. The success of stimulating salivary flow depends on the degree of remaining salivary gland function.

A masticatory stimulus can be provided by regular chewing action. The use of low caloric, sugarless foods such as celery or carrots can help stimulate salivary flow. The frequent use of sugarless chewing gum has been shown to increase the output of stimulated parotid saliva and increase the pH and buffering capacity of whole and parotid saliva, thus helping prevent tooth decay. Chemical stimulation of salivary flow may be achieved by substances such as citric acid, sour and sugarless candies, or lozenges. It should be mentioned that prolonged use of acid-containing substances can lead to dissolution of tooth enamel and irritation of dry, sensitive oral tissues. To alleviate this potential problem, oral moisturizing substances using a low concentration of citric acid saturated with calcium phosphate have been developed to stimulate salivary flow without the demineralizing effects of acids. These products should not contain alcohol or phenol, and should contain a sweetener such as sorbitol or xylitol that does not promote decay. occasionally, copious use of oral moisturizers containing artificial sweeteners may be limited by the development of diarrhea.

Oral pilocarpine, the systemic sialagogue that has been studied extensively, is a plant chemical substance obtained from the leaflets of South American shrubs from the genus pilocarpus. In tablet form, given in a total daily dose of fifteen-to-thirty milligrams per day, pilocarpine has been shown to be effective in stimulating salivary glands that have not been totally ablated by radiation therapy for head and neck carcinoma. Treatment results depend on residual gland function, and the optimal dose level for each patient must be assessed. In proper dosages, few cardiovascular side effects have been found, although pilocarpine tablets are contraindicated in patients with uncontrolled asthma and acute narrow angle glaucoma. The lowest effective dose should be used to maintain optimal salivary flow. The continuing effects of this drug depend on regular use. There is no daily crossover effect. Following radiation therapy, it may take up to 90 days of continued use before a noticeable salivary flow increase is appreciated, although an increased awareness of oral wetness is noted by many patients soon after pilocarpine therapy is initiated. Research data suggest that earlier treatment with pilocarpine tablets may be appropriate for many head and neck cancer patients who experience dry mouth symptoms early during the course of radiation therapy. When xerostomia and related sequela are not transient, which is often the case, lifelong therapy with pilocarpine tablets may be indicated. Use of pilocarpine for treatment of dry mouth and dry eyes due to Sjogren's Syndrome is now under study.

For individuals whose salivary glands do not respond to systemic or stimulatory treatment, or have a minimal response, "saliva substitutes" have been developed to moisten and "coat" the oral tissues. A true substitute for saliva has yet to be developed. Artificial saliva substitutes and mouth wetting agents may be used with some success, although the majority provide only short-term relief of symptoms, and can cause irritation of oral tissues during long-term use. All individuals with xerostomia should drink small sips of water or noncarbonated, sugarless liquids in order to moisten oral tissues and increase oral comfort. Room humidifiers can also be of benefit in promoting moisture of the oral tissues and tissues of the upper aerodigestive tract during the night, particularly during the winter months when rooms may be dry and overheated and the relative humidity is low.

Oral complications of xerostomia which require treatment include increased dental caries; oral infections; dehydration of the oral tissues; compromised chewing, swallowing and/or speaking; and oral pain. Dental caries associated with xerostomia typically affects the gingival third and the incisal edges or cusp tips of teeth, and teeth which generally have a low caries incidence, such as the lower anterior teeth, become more susceptible to decay. Because patients with xerostomia are more prone to tooth decay, their intake of sugar should be eliminated or greatly reduced as much as possible. Substances such as sorbitol, xylitol, aspartame, lycasin and saccharin may be substituted for sugars because they are not degraded into organic acids by oral bacteria. Dietary counselling is important for individuals with xerostomia.

Fluoride should be placed onto the teeth daily at home and during routine dental visits, to help prevent tooth demineralization and decay. Self-applied topical dental gels, rinses or foams can be used as a brush-on product or placed into fluoride carriers which resemble mouthguards. Such fluoride products containing neutral one-point-one percent sodium fluoride or zero-point-four percent stannous fluoride are available for home use. Chlorhexidine gel can be placed in a carrier which enhances the ability to control cariogenic flora in cancer patients with xerostomia. more frequent dental care is important for these patients. Depending on the caries risk, patients may need to be seen every three-to-four months.

Fungal infections frequently occur in patients with xerostomia, and patients with removable prostheses may be especially susceptible to such infection. These infections can be treated with a variety of antifungal agents. A chlorhexidine rinse can serve as a valuable antimicrobial adjunct, including use as a soaking agent for toothbrushes and dental appliances in order to prevent recurrence from reseeding. Dry mucosal tissues can be treated with frequent sips of water, moisturizing gels or vitamin e oil, and cracked lips will benefit from hydrophilic-based non-alcohol lubricating agents such as those containing aloe vera or vitamin e. Localized sore areas can be cautiously treated with topical anaesthetic agents, but the patient should be warned that these may interfere with taste and temperature sensation. The "masking" effect of topical anaesthetics on soft tissues can be a problem when tissues awaken following meals or toothbrushing, and the natural gag reflex that protects against food aspiration can be inhibited. Care should also be taken in preventing frictional tissue irritation by dental prostheses. Difficulties in swallowing and speaking that result from xerostomia may require specialized therapy from speech-language pathologists.

Xerostomia is a symptom associated with many causative factors. The diagnosis, treatment and management of xerostomia and its sequelae involve a multidisciplinary team of health care professionals. Psychological as well as physical factors must be evaluated and appropriately addressed; hence, the knowledge of the associated systemic as well as the oral consequences of xerostomia is imperative.

Saliva is not simply water. It is a complex bodily fluid that is an essential component of oral health and balance. The vital role of saliva, taken often taken for granted, becomes painfully and dramatically evident when this remarkable fluid is significantly reduced or missing. No one understands this better than the individuals who suffer from xerostomia and its myriad related complications. When all involved health care professionals communicate effectively and work together to meet the total needs of the xerostomic patient, the patient's quality of life and overall health can be greatly enhanced.