Dry mouth can be caused by various salivary gland disorders—including blockages and tumors—that impact the production and distribution of saliva throughout the mouth and throat.
The three major salivary glands, which are located near the jawline, are the parotid, the submandibular, and the sublingual. The bulk of an average person’s saliva is produced by the parotid and the submandibular; the sublingual only produces about 5%. Hundreds of smaller glands, known as the minor salivary glands, are also present throughout the mouth and throat to support the function of the major glands.
Salivary blockages
Salivary duct blockages are caused by cysts, salivary stones, or infections. Cysts may result from prior trauma to the glands, usually related to injury, radiation therapy, or surgery. Salivary stones can arise with a condition known as sialolithiasis. The stones, which are formed from calcium, can lodge in the ducts and inhibit the passage of fluids (Cedars-Sinai, n.d.). Infections cause inflammation, which in turn can close off some salivary ducts.
Parotitis and sialadenitis are two terms for salivary gland infections. Parotitis implies a bacterial or viral infection of the parotid gland, while sialadenitis is a bacterial infection. Viral salivary gland infections have been associated with mumps and HIV/AIDS. According to Cedars Sinai, “Coxsackie viruses, echovirus and cytomegalovirus” can also attack the salivary glands and cause inflammation (n.d.). Bacterial infections result from improper oral hygiene or from the presence of salivary duct stones. Individuals who already have low saliva flow are also more susceptible to bacterial sialadenitis.
Infection is usually accompanied by fever, mouth pain, and facial swelling. Viral infections are not treatable, and so they must run their course. Bacterial infections are addressed with antibiotics. If swelling is present, surgical drainage of the gland may be required.
Salivary gland tumors
Tumors of the salivary glands are usually benign, although patients with exposure to radiation may be at risk for cancerous salivary tumors. Tumors usually present themselves visually, as a large mass on a cheek, in the mouth, or on the tongue. As the mass gets larger in size, the patient will exercise increasing pain from the tumor.
More than three-quarters of all benign salivary tumors are what’s called pleomorphic adenomas, which typically appear in the parotid gland. This is a slow-growing tumor that can become very large over time if left untreated. Another common tumor affecting the salivary glands is Warthin’s tumor, which also tends to appear in the parotid gland. Warthin’s tumor has been associated with smoking and aging.
Salivary gland tumors are usually removed surgically.
Dry mouth symptoms resulting from these conditions may be managed with prescription and/or over-the-counter remedies, until the underlying condition has been resolved. If the salivary glands have been damaged, the patient may continue to suffer from dry mouth long after the underlying cause has been treated.
“The secretions of the salivary glands are of paramount importance for the maintenance of oral health” (Sreebny & Vissink, 2010).
The complex functions of saliva are generally taken for granted, until you personally experience a decrease in salivary production. Such a decrease leads to a variety of unpleasant conditions, including dry mouth, swallowing problems, tooth decay, and mouth infections. Based on these conditions alone, one could guess that saliva works to keep the mouth moist, prepare food for swallowing, and protect the teeth and mouth from dangerous bacteria. And, not surprisingly, this guess would be pretty close to accurate, as these are the primary functions of the saliva fluid.
Maintaining mouth moisture
Mouth moisture is important for comfort purposes, but it also plays a key role in oral hygiene. Saliva’s continued presence in the mouth has a cleansing function—it washes away food particles, debris, and bacteria that cause tooth decay and bad breath. When salivary production is limited, this washing process is less effective.
Preparing food for tasting and swallowing
Saliva makes food easier to swallow and tastier too. When saliva combines with bits of chewed food, it creates a moistened ball—called a bolus—that can move down the esophagus without tearing or scratching tissue on the way. Saliva also lines the esophagus as an additional layer of protection against chewed food.
The role saliva plays in tasting is relatively well documented. Saliva prepares food for tasting and stimulates the taste buds. Taste buds are less sensitive with dry foods, and so saliva’s moistening properties allow taste receptors to do their best work, so to speak. The fluid also helps transport the chewed food to the tongue, where the flavors can be recognized and enjoyed.
Taste is both a pleasurable and necessary part of eating. Once the tongue recognizes the flavors of the food, it signals the brain to begin producing the appropriate digestive fluids.
Protection of mouth and teeth
Saliva is also responsible for a host of protective actions, including:
- Maintenance of pH balance and neutralization of acids. The consumption of sugary foods, for example, can prompt changes in plaque pH and production of acids that erode tooth enamel and eventually result in tooth decay.
- Killing harmful bacteria. Saliva is loaded with antimicrobial components to protect your mouth (and your body) from harmful micro-organisms. These helpful components include antiviral, antifungal, and antibacterial proteins. Some harmful species can be destroyed by saliva, while others are merely contained to prevent overgrowth.
- Coating teeth. Saliva contains proteins that coat teeth and protect their surfaces from acid erosion.
- Promoting remineralization and limiting demineralization of teeth. The mucins in saliva coat the teeth to defend against calcium loss. When calcium loss does occur, the calcium within saliva promotes remineralization.
Saliva does far more than help you chew, taste, and digest your food. Indeed, it is a superhero defense against numerous tooth and mouth problems. If you are experiencing a decrease in saliva production, don’t discount your symptoms. Talk to your physician right away.