What Are Salivary Stones—Sialoliths?

Swelling and pain in your mouth might not always be from a toothache or gum condition. It could be from salivary stones, or sialolithiasis—a fairly common condition that happens when small mineral deposits block the salivary glands, where saliva is produced in the mouth. About a third of all salivary gland disorders are salivary stones.¹

These stones, medically called sialoliths, may be hard, yellow, or yellow-brown, slightly jagged, and about the size of a pea.¹ They are composed of layers of phosphate, calcium, magnesium, proteins, amino acids, carbohydrates, and other components.^1,2 And they usually weigh about 1 milligram to 6 grams and average about 300 milligrams.¹

Not only can salivary stones affect salivary glands, but they can also block the salivary ducts that connect your salivary glands to the rest of your mouth.³ These glands and ducts are found near your upper teeth, under your tongue, and on the floor of your mouth (below the jaw).⁴

Affecting 1 in 10,000 to 1 in 30,000 people, salivary stones—also called saliva stones, salivary duct stones, or salivary gland stones—are the most frequent cause of salivary gland swelling.^3,5 In some cases, salivary stones can lead to inflammation or infection in the mouth.³

What Causes Salivary Stones?

It's not entirely clear what causes salivary stones, but some experts believe they can form in the mouth if certain materials get trapped in the salivary ducts. The starter materials might be food debris and bacteria, as well as microcalculi—the natural microscopic mineral deposits from your salivary glands. These materials might then attract larger substances, eventually forming salivary stones.³

Some people may be predisposed to developing salivary stones, depending on several risk factors:

• Saliva composition: This is the natural chemical makeup of a person's saliva. People with salivary stones tend to have higher calcium and protein concentrations in their saliva, compared to those without stones.¹ These materials also make up salivary stones.
• Decreased antimicrobial activity of saliva: Your saliva naturally contains antimicrobial compounds that help break down bacteria cells.⁴ But factors such as smoking tobacco can reduce this antimicrobial activity, making your mouth more prone to harmful bacteria and other invaders—which make up salivary stones.¹
• Dry mouth: Your mouth might be dry, either from not drinking enough water or from a side effect of taking diuretics (water pills) or other medications. Less saliva flow could be a potential factor for food debris or bacteria buildup, though research for this risk factor is limited.³

More research is needed, however, to determine the exact cause of salivary stones and possible risk factors.³

Symptoms

The most common symptom of salivary stones is swelling in your salivary glands, followed by pain. Some people tend to notice swelling and pain more during mealtime when they are eating.¹ The pain often feels dull and comes and goes, sometimes for weeks or months.^1,6

In some cases, salivary stones can become lodged in the salivary ducts, blocking saliva flow. This can lead to inflammation, infections, and in rare cases, painful lumps of pus called abscesses.³

How Salivary Stones Are Diagnosed

If you suspect you have salivary stones, visit a healthcare provider.

In most cases, primary care or emergency medicine providers, as well as dentists, can help diagnose salivary stones by examining your mouth. Depending on the location and size of your salivary stones, your provider may use one or several imaging techniques for diagnosis and may also refer you to a radiologist.^3,6

X-rays

Standard dental X-rays are the most useful method for diagnosing stones located in the salivary glands beneath the jaw, called the submandibular glands.¹ About 80% of salivary stones are visible under X-rays or other radiographic imagery.³

Ultrasound

This is a noninvasive way to locate salivary stones without using radiation.³ It uses high frequency sound waves to visualize areas in the body. A provider can use ultrasound to detect salivary stones that are 2 millimeters or more in size, even during an active salivary gland infection.¹

Sialography

This is a standard radiographic imaging technique for salivary stones. It is most commonly used for diagnosing salivary stones located in the parotid glands—the salivary glands in front of and below your ears.^1,4 To perform a sialography for an affected gland, a provider injects a small needle of contrast—a type of dye—which will then help visualize the salivary ducts.³ However, this method is not recommended for severe cases of salivary stones nor for people who are allergic to the dye.¹

Other Imaging Techniques

To examine salivary stones in even greater detail, your provider might suggest a CT scan (computer tomography) or an MRI (magnetic resonance imaging).³

Sialendoscopy

This is a minimally invasive, nonsurgical technique that visualizes the salivary ducts using an endoscope—a long, thin probe with a small camera and light. A sialendoscopy requires local anesthesia and can help remove salivary stones as well. A provider can use the endoscope to flush a blocked salivary duct with saline (a mix of salt and water) or another anti-inflammatory rinse to potentially break up any salivary stones.¹

Salivary gland swelling may lead to a diagnosis of:³

• Salivary stones (sialolithiasis)
• Salivary gland infection (sialadenitis)
• Tumor growth (neoplasm)

About one quarter of people with salivary stones live with another health condition. People who develop salivary stones may be more likely to develop stones elsewhere in the body, like in the kidney or gallbladder.¹

Your provider can help you determine whether you have salivary stones or another condition with similar symptoms, such as:³

• Cellulitis
• Poor dental health
• A tooth infection with pus (dental abscess)
• Infections in spaces near the sides of the face
• Shingles in the mouth
• Tumor growth (neoplasm)

Treatment of Salivary Stones

Following a diagnosis, a healthcare provider can help remove salivary stones and treat symptoms.³

Standard Treatment for Salivary Stones

A provider will first ask you about your medical history related to salivary stones and then examine your mouth. Most cases of salivary stones can resolve with noninvasive treatments, including:^1,3

• Massaging the salivary glands: This can help with the removal of a salivary stone. A provider may assist you or teach you how to massage the glands properly.
• NSAIDs: Nonsteroidal anti-inflammatory drugs can help manage pain and swelling in the salivary glands.
• Sialogogues: These prescription drugs increase saliva production and can help flush out the stones.
• Antibiotics: A healthcare provider may prescribe antibiotics to treat an infection. Signs of an infection include swollen lymph nodes in the head and neck, as well as pus in the mouth.

Treatments for Difficult Removals

If noninvasive treatments are unable to remove your salivary stones, a healthcare provider will decide how to best remove them, depending on the size, number, and location of your salivary stones.³

These treatment options include:^3,6

• Sialendoscopy: This minimally-invasive procedure (also used for diagnosis) uses local anesthesia and an endoscope to flush the salivary ducts with saline to help remove blockage.
• External shockwave lithotripsy: In cases where the salivary stones are small (less than 7 millimeters) and not visible during sialendoscopy, external shockwave lithotripsy uses shock waves to break up the stones.
• Surgery: This is typically for removing larger salivary stones (larger than 7 millimeters) and only if all other treatments were unsuccessful. Your provider will refer you to an otolaryngologist (an ear, nose, and throat doctor) for a surgical procedure.

How to Prevent Salivary Stones

It might be tough to prevent salivary stones since the exact cause isn't known.³ However, general dental upkeep like regular brushing and flossing can help maintain your oral health overall. Avoid smoking tobacco, as it may be a potential risk factor of developing salivary stones.¹ Drinking water throughout your day and taking small bites when eating can also help prevent dry mouth and reduce your risk of mouth infections.⁶

Summary

Some people can develop salivary stones, possibly due to natural saliva components or other factors such as dry mouth. But a healthcare provider can usually help remove them during an oral exam or refer you to a specialist. Most cases of salivary stones show minor symptoms of pain and swelling in the salivary glands. If you are experiencing similar symptoms, visit a healthcare professional for a diagnosis and treatment plan.

Sources

1. Kraaij S, Karagozoglu K, Forouzanfar T, Veerman ECI, Brand HS. Salivary stones: symptoms, aetiology, biochemical composition and treatment. Br Dent J. 2014;217:E23. doi:10.1038/sj.bdj.2014.1054
2. Kraaij S, Brand HS, van der Meij EH, de Visscher JG. Biochemical composition of salivary stones in relation to stone- and patient-related factors. Med Oral Patol Oral Cir Bucal. 2018;23(5):e540-e544. doi:10.4317/medoral.22533
3. Hammett JT, Walker C. Sialolithiasis. StatPearls. 2020.
4. Vila T, Rizk AM, Sultan AS, Jabra-Rizk MA. The power of saliva: Antimicrobial and beyond. PLoS Pathogens. 2019. 15(11):e1008058 doi:10.1371/journal.ppat.1008058
5. Moghe S, Pillai A, Thomas S, Nair PP. Parotid sialolithiasis. BMJ Case Reports. 2012;2012. doi:10.1136/bcr-2012-007480
6. National Institute of Dental and Craniofacial Research. Saliva and Salivary Gland Disorders.