Understanding xerostomia
Special Report
By Laura Gater
Featured in AGD Impact, June 2006

Posted on Thursday, June 01, 2006

How well do we really understand xerostomia? In the past, xerostomia, or dry mouth, was considered a disease and blamed on physiological aging. In fact, xerostomia, which affects approximately 25 percent of the population, is largely related either to medication or autoimmune salivary gland disease that a patient is currently taking.

Xerostomia can cause difficulty for the patient when it comes to eating and swallowing. The patient also may experience burning of the tissues, irritation of the tongue, and painful ulcerations. Xerostomia increases susceptibility to caries and also to erosion and dentin hypersensitivity.

“In the past, xerostomia was not given much attention as a clinical problem,” explains Joseph L. Perno, DDS, FAGD, past president of the Academy of General Dentistry (AGD). “And, since it was considered a problem limited to very few individuals, there was not much emphasis placed on education and clinical evaluation. Today, general practitioners are seeing more and more patients with complaints of dry mouth, and therefore, it has become more of an issue to the profession, especially to the general practitioner in private practice.”

Causes of xerostomia

Xerostomia was not a great problem in the past because people did not take as many medications as they do today, according to Randy F. Huffines, DDS, president of the American Society for Geriatric Dentistry and director of dental geriatrics at the Quillen VA Medical Center in Mountain Home, Tenn. In fact, 32 million Americans today take three or more medications daily. Medications are the cause of more than 90 percent of xerostomia cases.

 “Many commonly prescribed medications can cause a decrease in [salivary] function,” says Dr. Perno. These medications include antihistamines, antidepressants, antipsychotics, antihypertensives, anti-inflammatories, diuretics, sedatives, and narcotics. In total, there are more than 400 medicines that may cause xerostomia.

Xerostomia also may be the result of Sjögren’s syndrome, a disorder of the immune system in which white blood cells attack the moisture-producing glands. The syndrome’s two most common symptoms are dry eyes and dry mouth.

Various other conditions may cause xerostomia as well, including diabetes, lupus, kidney diseases, stress, anxiety, depression, nutritional deficiencies, and a dysfunction of the immune system, such as caused by HIV/AIDS. In addition, nerve damage or trauma to the head and neck from wounds or surgery can damage the nerves that supply sensation to the mouth. In these cases, although the salivary glands may be intact, they cannot function normally without the nerves that signal them to produce saliva.

Treatments of certain conditions also may lead to xerostomia. Cancer therapy may affect the flow and composition of saliva. Radiation treatment on or near the salivary glands can temporarily or permanently damage the salivary glands.

Xerostomia and dental decay

Xerostomia can result in an increase in dental decay as a result of the lack of saliva. Prolonged reduction of saliva can lead to increased decay, as well as mouth ulceration, an increased susceptibility to infection, psychological distress, physical discomfort, and social embarrassment. When studying lesions, dental practitioners should observe the texture, color, and location of lesions in order to monitor them carefully. Pit and fissures and rough restorative margins can be treated with sealants that contain fluoride. Patient education about the prevention and causes of erosion are critical to prevent progression. Dental erosion is thought to be related to dentin hypersensitivity, as well (see related sidebar).

Diagnosing xerostomia

Although xerostomia is fairly common, diagnosis is often difficult due to the subjective nature of the condition. “If a patient says his or her mouth is dry, he or she may have xerostomia,” says Michael A. Siegel, DDS, MS, professor and chairman, diagnostic sciences, Nova Southeastern University College of Dental Medicine. “It is a subjective complaint, which varies by the individual. But you have to believe your patient, even if you think his or her mouth feels wet.”

“Most dentists will only approach the problem if a patient complains,” says Dr. Perno. “But some patients will not complain even if he or she does have xerostomia, so the dentist needs to look for and recognize the signs of dry mouth.”

To diagnose xerostomia, the dentist should look for an increase in dental caries, particularly cervical, proximal, and in the roots; cracking and fissuring of the tongue; frothy saliva; ulceration of oral mucosa; no pooling of saliva in the floor of the mouth; and recurrent oral candida infections. A mouth mirror or instrument that sticks to the soft tissue also can be an indication of xerostomia.

Recently, a new method was indicated for diagnosing xerostomia. In 2005, a preliminary study was performed to determine whether the Schirmer’s test, which is used to measure eye dryness, could be modified to measure mouth dryness. The results of the modified Schirmer’s test did show the test was able to distinguish between healthy adult volunteers and those who experienced profound xerostomia.

Managing xerostomia

One of the first steps in managing xerostomia is determining the severity of the condition. Dentists can employ various methods to measure a patient’s salivary flow. One method involves having the patient sit in an upright position with his or her head tilted forward so that the production of saliva is collected in the floor of the mouth and then flows out over the lip. Saliva formed is collected in a measure-cup for 15 minutes. The result of this collection is expressed as milliliters per minute. A flow of 0.25 ml per minute or more is considered normal, while a patient producing less than 0.1 ml per minute is at risk. Another method involves having the patient chew paraffin for five minutes and expectorate periodically into a measuring container. The saliva sample is then measured and the flow rate is calculated on a milliliter per minute basis. A flow of 1.0 ml per minute or more is considered normal, while a patient producing less than 0.7 ml per minute is at risk. Hyposalivation is the term used to describe when the patient is tested and actually demonstrates a reduced salivary flow. The salivary flow and Buffer capacity tests may be the only salivary indicators that can aid in determining caries risk.

When it comes to treating the condition, “common sense tells someone with xerostomia to drink more water to get an increase of saliva,” says Louis Malcmacher, DDS, FAGD, a general dentist in Bay Village, Ohio. In the past, dentists told patients to keep cherry pits in their mouths, chew gum, or suck on sugarless candies to get the salivary glands to produce more saliva, says Dr. Malcmacher. Milk was thought to be a good substitute for saliva, and patients are still advised to drink milk today.

Other palliative treatments that can be recommended to the patient—though these treatments do not cure the condition—include humidifying the air, filtering room air and smoke, using lip moisturizers, and avoiding alcohol-based mouthwashes. One of the most preferred treatments for xerostomia is sugar-free gum.

A number of studies have concluded that chewing gum increases salivary flow in patients to varying degrees. Sugarless sweets that contain citric and malic acid also can chemically induce saliva production, but the acidic content can dissolve tooth enamel.

Salivary substitutes and over-the-counter salivary mouthwashes, gels, and sprays have become increasingly sophisticated. They also are available for the patient and are designed to reduce the effects of xerostomia. A properly balanced artificial saliva should have a neutral pH and contain electrolytes, including fluoride, to correspond to the composition of saliva. These products aid in reducing plaque and stimulating saliva flow, which in turn helps strengthen teeth. However, says Dr. Malcmacher, with some of these over-the-counter salivary substitutes, “as soon as they are swallowed, they are gone.”

“Salivary substitutes, in general, only attempt to replace the lubricating function of saliva. They should be called oral moisturizers. Most are composed of carboxymethylcellulose, just like drops for dry eyes,” explains Dr. Huffines. “‘Salivary substitute’ is a misleading term.”

Some drug-induced xerostomia can be reduced if physicians change the dosage or brand of a patient’s medication. Dr. Siegel suggests that the dentist call the doctor who prescribed the medication and ask if it’s possible to switch the patient to a different medication in hopes of reducing the xerostomia symptoms.

There are medications that can help significantly with the problem of xerostomia as well. Pilocarpine hydrochloride, which is used to treat Sjörgen’s syndrome, helps to stimulate the saliva glands and can increase the production of saliva by up to 40 percent. “This may not sound like much, but if the patient has only a five percent production of saliva in the mouth, the 40 percent becomes very significant,” Dr. Malcmacher says. “They can eat better, swallow better, talk better, and their quality of life is better.”

According to the results of a randomized trial published in the Nov. 15, 2005, issue of the International Journal of Radiation Oncology, Biology and Physics, Ethyol® (amifostine) protects against xerostomia without affecting long-term outcomes for patients with head and neck cancer who undergo radiation therapy. Ethyol has been approved by the Food and Drug Administration (FDA) for the prevention of radiation-induced xerostomia. The 2005 study determined that patients who received Ethyol showed similar overall survival, progression-free survival, and local control rates to patients who did not receive Ethyol.

According to Dr. Siegel, cholinergic drugs also may be prescribed, though in consultation with the patient’s physician due to the drugs’ significant side effects. Pilocarpine and cevimeline dosages should be adjusted to increase saliva while minimizing adverse side effects, such as sweating and stomach upset. Patients should be warned that there is a wide range of sensitivity, and adverse side effects may exceed the desired increased salivation; if this occurs, then the cholinergic drug should be discontinued.

Electrostimulation also may provide some relief for some xerostomia sufferers. The Salitron System is an electric reflex salivary stimulation method for treating xerostomia. It is thought that electrostimulation of the tongue and the roof of the mouth simultaneously causes impulses to all of the residual salivary tissues in the pharyngeal and oral tissues, resulting in salivation. The Salitron System was approved by the FDA in 1988. However, there are critics of the system. Two years after the system was approved by the FDA, the Agency for Health Care Policy and Research (AHCPR) noted that there was “insufficient data to determine the clinical effectiveness of this modality of salivary production, or to identify those xerostomia patients who would benefit from the procedure.” In 1994, the American Dental Association (ADA) stated that “conventional modalities for the treatment of xerostomia do not include electrical stimulation.”

Treatment challenges

Some patients with dry mouth are predisposed to getting a candidiasis because of the lack of saliva. For these patients, an antifungal medication may be recommended to control the fungal overgrowth.

Patients with dentures also face challenges. “Dentures are harder to wear when you have dry mouth because they do not adhere to the tissues as well. People also tend to get more sore places under the denture because the lack of lubrication increases the frictional forces between the denture and the gums,” explains Dr. Huffines. “The saliva constantly remineralizes your teeth, so without it, the teeth can ‘melt away.’ This is especially true of root caries. Most dentists know very little about this.”

For the denture patient, the best strategy is to first be sure that the denture correctly adapts to the denture-bearing tissues. Since the bone that once held the natural teeth continues to resorb throughout life, many patients currently wear dentures that no longer fit and need to be remade or relined. Also, xerostomia patients are much more likely to have inflamed tissues, called denture stomatitis, since they are more susceptible to yeast infections. After being assured that the dentures fit properly and the patient’s tissue health has been optimized, oral lubricants, or saliva substitutes, may be applied to the denture-bearing areas just before eating to increase lubrication under the denture. Also, properly applied denture adhesives may help, as long as they are not just a cover-up for an ill-fitting denture.

Learn more

It is important for general practitioners to be aware of the possibility of xerostomia, and to learn how to diagnose and treat the condition. The cause must be determined before treatment can be effective. “The approach to managing the patient has to follow a logical progression,” says Dr. Perno. “It should be part of the comprehensive evaluation. Symptoms should be noted and signs should be recognized in order to properly diagnose the condition. Treatment should be based on all of that gathered information.”

 Learn more by attending a special symposium, “Unraveling the Mysteries of Saliva: Its Importance in Maintaining Oral Health,” hosted by Dr. Perno, at the 2006 AGD Annual Meeting & Exposition. The symposium, sponsored by GlaxoSmithKline, will be presented on August 6, from 8 a.m. to 11 a.m., by Thomas C. Abrahamsen, DDS, and Harold Crossley, DDS, PhD. Dr. Abrahamsen is a leading expert on tooth erosion and Dr. Crossley is a leading expert in pharmacology.

Those who attend the symposium will learn about the causes of xerostomia and how to improve the quality of life of patients suffering from it. Tooth erosion, decay, and sensitivity also will be discussed.

Simple management strategies for patients

• Perform oral hygiene at least four times daily, after each meal and before bedtime.
• Rinse and wipe oral cavity immediately after meals.
  Brush and rinse dentures after meals.
• Use only toothpaste with fluoride.
  Keep water handy to moisten the mouth at all times.
• Apply prescription-strength fluoride gel at bedtime as prescribed.
• Rinse with a salt and baking soda solution four to six times daily.
• Avoid liquids and foods with high sugar content.
• Avoid overly salty foods.
• Avoid citrus juices (orange, grapefruit, tomato).
• Avoid rinses containing alcohol.
• Use moisturizer regularly on the lips.
• Try salivary substitutes or artificial saliva preparations, which may relieve discomfort by temporarily wetting the mouth and replacing some of the constituents of saliva.
• Use oral pilocarpine as prescribed.

Source: http://www.oncolink.org/

Dental erosion and its impact on dentin hypersensitivity

Dental erosion may be related to dentin hypersensitivity. Patients with dentin hypersensitivity don’t always tell their dentist or dental hygienist that they have the condition. Many patients are not aware that tooth sensitivity can be treated, or they fear that it is a symptom of a more serious condition. As a result of hypersensitivity, some patients may avoid taking proper care of their teeth, which can lead to more serious problems.

According to David H. Pashley, DMD, PhD, a regents professor of oral biology and maxillofacial pathology and the director of bioengineering research at the Medical College of Georgia’s School of Dentistry, there are two possible causes of hypersensitivity: the tubules are overconductive and permit too much fluid movement within or the pulpal nerves become hypersensitive due to plaque products that diffuse across dentin to the pulp where the nerves are located. These bacterial products can produce a very mild inflammation of the pulp (not pulpitis) under the exposed tubules. Many patients also develop sensitivity under crowns, fillings, and veneers due to incomplete bonding and loss of cement. This phenomenon is known as the hydrodynamic theory.

“If the patient just had periodontal surgery involving scaling of exposed root surfaces covered with calculus, the cementum that normally seals the ends of dentinal tubules may be removed along with the calculus,” Dr. Pashley explains. “This exposes the peripheral ends of the dentinal tubules and permits minute shifts of dentinal fluid either inward or outward, both of which activate mechanoreceptor nerves in the pulp and cause pain.”

Overzealous tooth brushing also can cause sensitivity. Some patients use hard bristle brushes, brush with too much pressure, or use more abrasive substances (e.g., baking soda). When tooth brushing is the culprit, the gum will recede and the tooth structure will wear away at the gum line, causing sensitivity and a notching or hole, which becomes an area where plaque and food accumulate, Dr. Perno says. Many times restorative treatment must be done to cover the areas. Dentists may apply “bonding agents” to close the pores of the tooth root. Dentists also may use “oxalate” compounds that, when rubbed on the root, will reduce if not eliminate the sensitivity. Dentists also may prescribe high fluoride content mouthwashes that can help reduce tooth sensitivity.

When patients avoid brushing sensitive areas, the result can be decay and gum problems. Sensitivity to chewing, as well as to hot and cold, are symptoms of this problem. As a result, individuals often may change their eating habits. They may not chew their food as well. In extreme cases, they may limit their diet to softer foods with minimal temperature variance.

Sensitivity also may be caused by tooth whitening treatments. In fact, according to an article published in the Compendium of Continuing Education in Dentistry (April 2003), sensitivity is the most common side effect of over-the-counter and professionally-dispensed tooth whitening treatments. Data suggests that up to 75 percent of tooth whitening patients may experience sensitivity.

In-office whitening procedures have a long history of producing tooth sensitivity and gingival irritation. The higher the concentration of peroxide in tooth whitening products, the greater the incidence and severity of tooth sensitivity. According to Van B. Haywood, DMD, a professor in the Department of Oral Rehabilitation at the Medical College of Georgia’s School of Dentistry, as many as 41 percent of dentists recommend that patients discontinue their whitening procedures to alleviate related sensitivity. He notes, however, that a recent study demonstrated that applying potassium nitrate by trays for 10 to 30 minutes could reduce sensitivity for more than 90 percent of patients, thus enabling them to successfully complete their whitening procedure.

Hypersensitivity is much easier to prevent than to cure. Dr. Pashley believes that dentists do not spend enough time with patients on tooth brushing instruction. “Treatment should start with tooth brushing instruction and using a desensitizing toothpaste with a soft-bristle brush,” he says. “The use of oxalates, or topical solutions like Sensodyne®, also is helpful.”

A recent study published in the Journal of Clinical Dentistry (Winter 2005) demonstrated that patients who brushed with Sensodyne twice a day, for two weeks before and two weeks during professional whitening treatment, experienced less sensitivity than a control group that used regular toothpaste. Patients who brushed with Sensodyne were significantly less sensitive during the first three days of their whitening treatment, the period when they typically would experience the greatest degree of whitening-related sensitivity. Sensodyne contains the maximum amount of potassium nitrate allowed by the FDA to treat sensitivity.

Treatment of dentin hypersensitivity depends on the severity and incidence. Occasional episodes, especially if they are related to the ingestion of acids, can be treated by brushing with a desensitizing toothpaste containing 5 percent potassium nitrate (all U.S. desensitizing toothpastes contain potassium nitrate) or applying the potassium nitrate by trays. Topical fluoride application, either in gels or in concentrated toothpaste, also can be effective.

“Spot application of highly concentrated fluoride or fixating materials is possible if the area is accessible to touch and localized to a specific area,” explains Dr. Haywood. “Bonding agents or restorations also may be indicated. More esthetically, periodontal surgery to cover the denuded root is very desirable for sensitivity; however, if bonding agents or restorations have been previously placed, this is no longer an option to obtain attachment of the gingiva to the root and control the sensitivity.”

A new ingredient that is primarily used for remineralization of enamel, amorphorous calcium phosphate (ACP), also is being proposed for sensitivity treatment, notes Dr. Haywood. However, early clinical trials have not indicated it to be very successful. “More data is needed and should be coming as we see this introduced in prophy paste and other restorative materials,” he explains. “Proper research, not single episode incident reports, will finally resolve this question.”

According to Dr. Pashley, there have never been any clinical followup studies to see if patients who have been cured of hypersensitivity actually develop sensitivity in the same regions of the same or different teeth. He says, “No treatment for dentin hypersensitivity will be successful unless the patient avoids the main contributors to hypersensitivity, which include improper tooth brushing, exposure to food acids, and improper use of toothpicks and bobby pins.”

Identifying dentin hypersensitivity

These questions should be asked at each patient visit:

• Do you avoid specific foods or beverages that cause tooth sensitivity or pain?
• Do you experience discomfort from cold, hot, sweet or sour foods or beverages?
• Have you recently undergone a whitening or bleaching treatment? If so, did you discontinue or interrupt treatment because of tooth sensitivity?
• Are you considering utilizing whitening or bleaching treatments in the future?

Source: GSK Consumer Healthcare, http://www.dental-professional.com/

Causes of dentin hypersensitivity

Brushing habits
Sustained and overzealous brushing (especially with harder-bristled brushes) is known to thin enamel and cause gingiva to recede, exposing the softer subgingival cementum, which is also damaged by brushing. Right-handed people tend to brush their left teeth more zealously and vice versa, which results in hypersensitivity in those teeth. Also, people tend to brush the front teeth and outer tooth surfaces more zealously; those areas are more likely to be sensitive than back teeth and inner surfaces.

Tooth grinding
Patients who grind their teeth experience a higher incidence of dentin hypersensitivity. This action wears down the enamel on teeth, exposing the dentin.

Gender
Women are more prone to dentin hypersensitivity. This is because women, generally speaking, are more attentive to basic hygiene. Since this includes dental care, female teeth are more likely to have exposed dentinal tubules.

Age
Dentin hypersensitivity does not occur in most people until they reach their late 20s, 30s, or 40s because overzealous brushing and other factors begin to take their toll at this time.

Diet
Habitual ingestion of acidic substances causes erosion of enamel and dentin, subsequently opening dentinal tubules. The citric acid in citrus fruits (e.g., lemons), as well as the ingestion of other acidic foods and beverages (e.g., ginger ale, which has the lowest pH of any drink commonly available), should be avoided whenever possible. Brushing directly after ingestion of these substances also must be avoided because it causes direct damage to enamel.

Smokeless tobacco
Users of smokeless tobacco more frequently experience dentin hyper-sensitivity. The “quid” of smokeless tobacco placed between the gum and cheek is a well-known cause of gingival recession. As the gingiva recede, softer subgingival cementum is exposed. Continual brushing erodes the cementum, opening the dentinal tubules.

Disease
There is an increased risk for dentin hypersensitivity in bulimics and those afflicted with gastroesophageal reflux disease. Both conditions increase intraoral acidity, subsequently causing the type of enamel erosion that leads to dentin hypersensitivity. Periodontal disease and gum disease also may result in dentin sensitivity since the tooth’s root surface is exposed through recession of the gums or loss of supporting ligaments.

Source: U.S. Pharmacist, July 2001

Medication types that may cause xerostomia include:

• Anorexiant
• Antiacne
• Antianxiety
• Anticholinergic/antispasmodic
• Anticonvulsant
• Antidepressant
• Antidiarrhetic
• Antihistamine
• Antihypertensive
• Anti-inflammatory analgesic
• Antinauseant/antiemetic
• Antiparkinsonian
• Antipsychotic
• Bronchodilator
• Decongestant
• Diuretic
• Muscle relaxant
• Narcotic analgesic
• Sedative

Source: www.seattle-dentist.com/xerostomia.htm