Salivary duct stones (or salivary gland stones) are minerals that are formed in the tubes through which saliva passes. The stone partially blocks the passage of saliva and so, for example, during the meal a considerable amount of produced saliva can not flow through the salivary duct, therefore the gland swells because of the saliva. This rare disorder usually affects the submandibular glands at the base of the mouth.
What to do?
If you feel the swelling under the chin or behind (or underneath) the jaw angle, and especially if the swelling increases during meals, contact your doctor or dentist. The X-ray image should points out to the problem, but if it does not, it will be necessary to examine you with sialography.
If you have a stone in the salivary duct, a doctor will remove it with local anesthesia. Occasionally, the problem re-occurs; in that case, a minor operation is performed in which a small opening is made near the salivary duct. The opening allows the saliva to bypass the salivary duct and goes into the mouth almost directly from the gland. With this, any possibility of further stone formation and damaging the salivary duct is avoided.