(A) Overview 1, salivary stone disease is a series of lesions caused by calcified masses in the gland or duct. 85% occurs in the submandibular gland, followed by the parotid gland, occasionally seen in the upper lip and lip and cheek minor salivary glands, sublingual glands are rare. Salivary stones often block saliva drainage and cause secondary infection, resulting in glandular deformity or recurrent inflammation. 2.Etiology and pathology The etiology of salivary stone is still unclear, there are numerous theories, such as bacterial theory, injury theory, metabolic theory, inflammation theory, foreign body center theory, etc. In recent years, various modern means and methods are used to examine and analyze, but still fail to elucidate the etiology of salivary stone. The salivary stone mostly occurs in the submandibular gland, which is related to the following factors: ① The submandibular gland is a mixed gland, and the saliva secreted is rich in mucin, which is called parotid secretion stagnant, and the calcium content is also two times higher, and the calcium salt is easily deposited. ②The submandibular gland ducts travel from the bottom up, and the gland secretion flows against the direction of gravity. The duct is long and has a curved part at the back of the floor of the mouth, and the full name of the duct is zigzag. All these anatomical structures make saliva easy to stagnate and lead to salivary stone formation. Salivary stones are located in different parts and have different shapes, those in the ducts are mostly shuttle-shaped and those in the glands are mostly round or ovoid. Their size varies greatly, from fine sand grains to several centimeters; the number is generally l-2, more than 10. Salivary stones are light yellow or brown, some hard, some soft, with a laminar profile and one or several cores in the center. The chemical composition of salivary stones is mainly calcium phosphate (70-75%) and calcium carbonate (10-15%), apatite structure, some studies in recent years have shown that it is mainly carbonate apatite rather than apatite, a few for calcium triphosphate, and some trace elements such as Mg, Fe, Zn, etc.. Salivary stones are often complicated by submandibular adenitis, and histopathology shows that the early stage of the disease is a hyperplasia of the epithelium of the ducts where the salivary stones are located, infiltration of surrounding inflammatory cells, and force of the ducts in the gland. Zhang, the lumen of the duct is filled with salivary fluid and inflammatory cells, with the development of the lesion, the duct epithelium appears squamous or cupped cell transformation, the duct with fibrous connective tissue hyperplasia, glandular vesicle atrophy, the late stage of the lesion glandular tissue completely fibrosis, known as chronic sclerosing submandibular adenitis, also known as Künner’s tumor. (B) diagnostic ideas: the diagnosis can be confirmed according to clinical manifestations and X-rays. 1, clinical manifestations: sometimes the pain is severe, pinprick-like, called “salivary colic”. Soon after stopping eating, the gland will recover by itself and the pain will disappear. The mucous membrane at the mouth of the duct is red and swollen, and a small amount of purulent secretion can be seen overflowing from the mouth of the duct when the gland is squeezed. ③The salivary stone in the duct can be palpated with both hands and there is pressure pain. There was inflammatory infiltration under the oral mucosa at the site of pressure pain. ④Salivary stone obstruction causes secondary infection of the gland with recurrent episodes. Infection of the submandibular space can be caused by the spread of inflammation to adjacent tissues due to incomplete envelope and loose tissue of the submandibular gland. In some cases, acute inflammation of the submandibular or sublingual region may be manifested at the outset, while obstructive symptoms are not apparent. Patients with chronic submandibular adenitis have a milder clinical presentation, prompted by recurrent swelling during feeding and not severe pain. The examination of the gland is moderate in texture and there may be purulent discharge from the mouth of the duct. The former is used for salivary stones in the more anterior part of the submandibular gland duct, and the latter is used for salivary stones in the posterior part of the submandibular gland duct and in the gland. Salivary stones with low calcification, i.e., negative salivary stones, are difficult to show on radiographic plain films. After the acute inflammation has subsided, salivary gland angiography is used. The salivary stone is located in a round or oval filling defect. For diagnosed salivary stones, imaging is not performed to avoid pushing the salivary stone deeper. (1) Submandibular lymphadenitis Repeated enlargement, but not related to eating, normal secretion of submandibular glands. The submandibular lymph nodes are superficial, easily palpable and often painful to the touch. (2) Sublingual gland tumor Most of the sublingual gland tumors do not have ductal obstruction symptoms, but there are very few patients with incomplete obstruction symptoms due to tumor compression of submandibular gland ducts and no salivary stone on X-ray. (3) Chronic sclerosing submandibular adenitis, or Küttner’s tumor, presents as a hard nodular mass. Patients with this disease may have a history of swelling from eating or discharge of salivary stones, and the mass is hard but usually not large and does not show progressive enlargement. (4) Infection of the submandibular space Patients with a history of toothache and detectable focal teeth have a hard infiltrative swelling of the submandibular area with flushed skin and depressed edema. Submandibular gland duct secretion may be normal without salivary stone obstruction symptoms. (5) Submandibular gland tumor is progressively enlarged. There is no history of feeding swelling or inflammatory episodes of the submandibular gland. (3) Treatment: The aim of treatment for submandibular salivary stone disease is to remove salivary stones, eliminate obstructive factors, and preserve the function of the submandibular gland to the greatest extent possible. However, when the gland has lost its function, the lesion should be removed. 1.Conservative treatment Very small salivary stones can be treated conservatively by asking the patient to take acidic food and vitamin C tablets by mouth to promote salivary secretion, which is expected to be discharged by itself. 2.Salivary stone extraction is suitable for those who can find salivary stones in the area before the second mandibular molar, without history of repeated infection of submandibular gland, the gland is not yet fibrotic and the gland function exists. For larger submandibular gland duct stones, it is advisable to perform duct recanalization to allow saliva to drain from the normal duct opening, which is conducive to the recovery of submandibular gland function after surgery. After surgery, salivary stimulants can be used to promote saliva secretion and the patency of the duct system to avoid reobstruction of the duct. 3.Glandular excision For salivary stones located in the submandibular gland or in the posterior part of the submandibular gland duct and the glandular portal. Those with recurrent infection of the submandibular gland or secondary chronic sclerosing submandibular adenitis and glandular atrophy, which have lost their uptake and secretion functions. (IV) Prognosis evaluation The prognosis of this disease is good. (V) Recent progress and outlook: In recent years, extracorporeal vibration waves have been used to crush the stones in the posterior part of the submandibular glands and ducts, and to lyse the stones to less than 2 mm in diameter so that they can be excreted by themselves or after stimulation with saliva. The use of fiberoptic endoscopy to enter the ducts of the submandibular gland to retrieve stones has been reported.