Dry mouth, or xerostomia is simply the perception that there’s not enough saliva in a person's mouth.
Nearly everyone has experienced dry mouth, but for some people the condition is chronic. It can even compromise their health or be a symptom of an underlying disease or condition. The feeling of dry mouth is sometimes subjective, and there are some conditions where the patient feels like their mouth is dry even as their salivary glands are working normally. Dry mouth is fairly common among older people. However, medical researchers believe this is not a function of age but of the fact that older people are more likely to take drugs that cause dry mouth.
Dry Mouth Causes
Most cases of dry mouth are the result of the salivary glands not working the way they should. The salivary glands are three pairs of glands found in the mouth and cheek. The parotid glands are found in front of the ears. The submandibular glands are found under the lower jaw, and the sublingual glands are found under the tongue. Other, smaller glands in the mouth also help produce saliva.
Medications are a major cause of dry mouth. There are hundreds of drugs that cause the salivary glands to not produce the amount of saliva that they normally would. Among the medicines that can cause dry mouth are:
• Diuretics
These are drugs that make the kidneys excrete more urine to eliminate excess fluid from the body. Potassium and sodium are also excreted at higher levels in a person who takes diuretics.
• Anticholinergics
These drugs dampen nerve impulses in the parasympathetic nervous system to regulate the workings of the GI tract, the bladder, the heart or other organs.
• Sympathomimetics
These drugs act like adrenaline, a hormone secreted by the adrenal glands atop the kidneys.
A person who is undergoing radiation therapy around their head and neck can experience dry mouth when the radiation causes damage to the salivary glands. Chemotherapy can thicken the saliva and cause the patient’s mouth to feel dry.
Damage to the nerves that stimulate the salivary glands to produce saliva can cause xerostomia. Dry mouth is a complication of diseases such as diabetes, AIDs and Sjögren's syndrome (1). Sjögren's syndrome is an autoimmune disease where the patient’s own immune system attacks tissues that produce moisture, which include the salivary glands.
Other causes of dry mouth include:
• Vomiting
• Mouth breathing
• Hemorrhage
• Diarrhea
• Fever
• Kidney failure
• Use of recreational drugs such as marijuana, heroine, methamphetamine and LSD
• Hepatitis C, an infection of the liver
• Sarcoidosis, a disorder where inflammatory cells appear in various organs in the body
As mentioned, people with conditions such as stroke or Alzheimer’s disease may feel like their mouths are dry even though their salivary gland are functional. This probably has something to do with damage to the brain that doesn’t allow them to feel that their mouths are moistened.
Symptoms of Dry Mouth
Patients who have dry mouth report that their mouths are both dry and sticky, and this causes them to have problems speaking, swallowing and chewing. Dry mouth prevents them from tasting or even smelling their food properly. Sometimes the sense of dryness extends down into the patient’s throat.
Patients with dry mouth are constantly thirsty and may have a burning sensation in the throat. Their lips are dry and cracked, their tongue is rough and fissured, and their gums can become irritated and inflamed. Dry mouth can lead to mouth ulcers, rampant tooth decay, bad breath and infections. A person may become malnourished if they can't eat because their mouth is too dry for them to chew and swallow their food. Patients who need dentures have trouble wearing them.
The salivary glands themselves can become infected, for there is little saliva to wash out the bacteria that would otherwise invade the salivary ducts.
Oral candidiasis is another complication of dry mouth. This is a yeast infection that’s also called thrush. It is caused by the Candida albicans fungi. It affects the gums, the tongue, the soft palate, the cheeks and the lips. Thrush presents as cheesy plaques that are hard to wipe off. If they are wiped off, they leave ulcers behind.
There are even symptoms of xerostomia that seem to have nothing to do with the mouth. The person might not be able to cry and have dry eyes and blurry vision. They might not be able to tolerate bright lights well and may experience dryness in other mucous membranes such as the inside of the nose.
Remedies
A person who has dry mouth should go to the doctor or dentist to learn more about dry mouth causes remedies. In the meantime, they can drink lots of water or sugarless beverages. They should stop drinking liquids that have caffeine or alcohol which dry the mouth. Smoking also dries out the mouth.
A humidifier can be set up in the patient’s bedroom and turned on while they sleep.
Water should be taken with meals to help with chewing and swallowing. Water also enhances the taste of food. The best way for a patient with dry mouth to take water and other beverages is through a straw. The patient should chew sugarless gum or eat sugarless candy to stimulate the salivary glands. They should avoid highly seasoned and salty foods, for they may hurt the tissues of the mouth. They should avoid foods that are sugary, acidic or sticky.
One of the jobs of saliva is to protect the teeth and suppress pathogens in the mouth. A person with xerostomia needs to pay extra attention to their dental hygiene. The patient needs to brush and floss their teeth twice a day, and use a toothbrush with the softest bristles and a fluoride toothpaste to support the enamel on their teeth. They should brush after eating, especially if they’ve eaten something sugary. They also have to make sure that they make and keep dental appointments. People with xerostomia should visit their dentist at least twice a year.
Doctor’s Treatment
Besides home remedies, the patient’s doctor can help with dry mouth, though successfully treating the disorder can be challenging. The doctor measures the rate of the flow of saliva through sialometry.
There are several sialometry (2) techniques. In one, the patient simply waits for saliva to collect at the floor of their mouth then spits it into a tube. In another, they are asked to chew on a piece of wax or gauze pad, then either spit out the saliva or have the doctor weigh the pad. Another technique uses suction cups over the tiny salivary ducts in the mouth to collect the saliva. The doctor can notice signs of dry mouth without testing. They include the tongue depressor sticking to the patient's tongue or lipstick stains on a female patient’s teeth.
The doctor can prescribe saliva substitutes or artificial saliva. One treatment is a powder made of supersaturated calcium phosphate that’s dissolved in water. This creates a solution very much like natural saliva. The patient rinses their mouth with this solution several times a day. Sometimes, relief can come from simply drinking milk or taking vegetable oil.
The doctor can prescribe substances that stimulate the salivary glands, but these only work if the salivary glands are still functional. These can be as easy to obtain as sugar free mints, citrus-flavored hard candies, chewing gum or fruit acids. A drug called pilocarpine hydrochloride has been seen to be effective in stimulating the salivary glands. This drug is also used to treat glaucoma and ocular hypertension, but when taken by mouth it eases xerostomia, especially if it’s caused by radiation or Sjögren's syndrome.
Conclusion
Dry mouth is a frustrating condition and has implications for a person's health if the salivary glands really aren't producing saliva the way they should. The good news is that most cases of dry mouth can be eased through relatively simple measures.