One or more stones sometimes form in one of the salivary glands. A stone can cause a blockage of the flow of saliva, which can lead to pain and swelling of the affected salivary gland. The reason why these stones form is not known. Sometimes a stone comes out into the mouth on its own, or with gentle probing. However, in many cases a small procedure is needed to remove the stone.
The salivary glands make spit (saliva). Saliva is important in the breaking down of the food that you eat. It makes food moist, lubricating it as it passes from the mouth to the gullet. It also contains enzymes in the saliva which break down some of the starch and fat in your food.
There are three pairs of glands that make saliva. Saliva drains into the mouth from these glands down short ducts (tubes). The submandibular glands are under the floor of your mouth - one on each side - and drain saliva up into the floor of your mouth. The parotid glands lie just below and in front of your ears. Saliva passes down the parotid duct into the inside of your cheeks. The sublingual glands are just beneath your tongue.
You make small amounts of saliva all the time to keep your mouth moist. When you eat, you normally make much more saliva which pours into your mouth.
The chemicals in saliva can sometimes crystallise into a stone that can then block the salivary ducts. Some people form one or more small stones in a salivary gland. This occurs most commonly in people over the age of 40, although it can occur at any age.
The reason why a stone forms is not known. A salivary gland stone is sometimes called a sialolith or a salivary calculus. Most salivary stones are mainly made of calcium. However, there is no abnormality of the blood calcium level or any other problem with calcium in your body. Salivary gland stones are not usually associated with any other diseases.
The size of the stone can vary from less than 1 mm to a few centimetres in diameter. About 9 in 10 stones are less than 10 mm in size.
About 8 in 10 salivary stones form in one of the submandibular glands. The submandibular duct is a tube, which runs from under the front of the tongue to the submandibular gland. The larger parotid glands make saliva that is thinner than that produced by the submandibular glands. This means that stones less commonly form in parotid glands. It is rare for a stone to form in a sublingual gland.
When saliva cannot exit a blocked duct, it backs up into the gland, causing pain and swelling of the gland. The most common symptoms are pain and swelling of the affected gland at mealtimes. This occurs if the stone completely blocks a duct. The saliva cannot pass into your mouth if the duct is blocked by a stone. The pain can be sudden and intense just after starting a meal. Swelling soon follows. The pain and swelling ease over about 1-2 hours after a meal.
However, most stones do not block a duct completely. A stone may only partially block saliva flow or not block the flow at all if it is embedded in the body of the gland. In these situations the symptoms can vary and include one or more of the following:
Some people with salivary gland stones have no symptoms at all. A stone may be found by chance on an X-ray picture taken for another reason.
Symptoms are often typical and the diagnosis is usually clear. A doctor can sometimes feel or see a stone at the opening of a duct. An ordinary X-ray test can detect and show the position of about 8 in 10 salivary stones. No further tests are then needed.
However, in about 2 in 10 cases, the stone does not show on an X-ray and other tests may be needed. The test done may be one of the following:
Most stones that cause symptoms will not go away unless they come out or are removed. Sometimes a small stone comes out into the mouth by itself. If that does not occur, possible treatment options and procedures include the following:
A salivary stone is usually a one-off event. After it is removed there are usually no further problems. However, some people develop one or more further stones at some later time. Sometimes several stones form in the same gland. An operation to remove the whole gland may be an option for people who develop recurring or multiple stones. (You will make enough saliva by your remaining glands if one is removed.)
As the exact cause of salivary stones is not known, there is no clear way to prevent them. However, it is important to drink plenty of fluids, especially if you exercise frequently or live in a warm climate.