Salivary gland hypoplasia is relative underdevelopment of the Salivary glands. [1] Salivary gland hypoplasia tends to produce xerostomia (dry mouth), with all the associated problems this brings. [1] [2]
It is a rare condition, [2] which may occur as a congenital abnormality or result from lack of neuromuscular stimulation. [1]
It may be associated with Melkersson–Rosenthal syndrome, [1] [2] and hereditary ectodermal dysplasia. [1]
Saliva is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells, enzymes, and antimicrobial agents.
The salivary glands in many vertebrates including mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands, as well as hundreds of minor salivary glands. Salivary glands can be classified as serous, mucous, or seromucous (mixed).
The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the mandibular ramus, and secretes serous saliva through the parotid duct into the mouth, to facilitate mastication and swallowing and to begin the digestion of starches. There are also two other types of salivary glands; they are submandibular and sublingual glands. Sometimes accessory parotid glands are found close to the main parotid glands.
The sublingual gland is a seromucous polystomatic exocrine gland. Located underneath the oral diaphragm, the sublingual gland is the smallest and most diffuse of the three major salivary glands of the oral cavity, with the other two being the submandibular and parotid. The sublingual gland provides approximately 3-5% of the total salivary volume.
Xerostomia, also known as dry mouth, is a subjective complaint of dryness in the mouth, which may be associated with a change in the composition of saliva, or reduced salivary flow, or have no identifiable cause.
Parotitis is an inflammation of one or both parotid glands, the major salivary glands located on either side of the face, in humans. The parotid gland is the salivary gland most commonly affected by inflammation.
Ectodermal dysplasia (ED) is a group of genetic syndromes all deriving from abnormalities of the ectodermal structures. More than 150 different syndromes have been identified.
A ranula is a mucus extravasation cyst involving a sublingual gland and is a type of mucocele found on the floor of the mouth. Ranulae present as a swelling of connective tissue consisting of collected mucin from a ruptured salivary gland caused by local trauma. If small and asymptomatic further treatment may not be needed, otherwise minor oral surgery may be indicated.
An oral medicine or stomatology doctor/dentist has received additional specialized training and experience in the diagnosis and management of oral mucosal abnormalities including oral cancer, salivary gland disorders, temporomandibular disorders and facial pain, taste and smell disorders; and recognition of the oral manifestations of systemic and infectious diseases. It lies at the interface between medicine and dentistry. An oral medicine doctor is trained to diagnose and manage patients with disorders of the orofacial region.
The Stafne defect is a depression of the mandible, most commonly located on the lingual surface. The Stafne defect is thought to be a normal anatomical variant, as the depression is created by ectopic salivary gland tissue associated with the submandibular gland and does not represent a pathologic lesion as such. This cavity is commonly observed on panoramic radiograph.
Salivary gland tumours, also known as mucous gland adenomas or neoplasms, are tumours that form in the tissues of salivary glands. The salivary glands are classified as major or minor. The major salivary glands consist of the parotid, submandibular, and sublingual glands. The minor salivary glands consist of 800 to 1000 small mucus-secreting glands located throughout the lining of the oral cavity. Patients with these types of tumours may be asymptomatic.
Salivary gland diseases (SGDs) are multiple and varied in cause. There are three paired major salivary glands in humans: the parotid glands, the submandibular glands, and the sublingual glands. There are also about 800–1,000 minor salivary glands in the mucosa of the mouth. The parotid glands are in front of the ears, one on side, and secrete mostly serous saliva, via the parotid ducts, into the mouth, usually opening roughly opposite the second upper molars. The submandibular gland is medial to the angle of the mandible, and it drains its mixture of serous and mucous saliva via the submandibular duct into the mouth, usually opening in a punctum in the floor of mouth. The sublingual gland is below the tongue, on the floor of the mouth; it drains its mostly mucous saliva into the mouth via about 8–20 ducts, which open along the plica sublingualis, a fold of tissue under the tongue.
Salivary gland aplasia is the congenital absence of salivary glands. Usually the term relates to the absence of some or all of the major salivary glands.
Salivary gland atresia is congenital blockage or absence of the orifice of a major salivary gland duct or part of the duct itself.
Ectopic salivary gland tissue which is located in sites other than the normal location is variously described as aberrant, accessory, ectopic, heterotopic or salivary gland choristoma.
Human immunodeficiency virus salivary gland disease, is swelling of the salivary glands and/or xerostomia in individuals infected with human immunodeficiency virus.
Sialodochitis, is inflammation of the duct system of a salivary gland. This is compared to sialadenitis, which is inflammation of the gland parenchyma.
Ductal papilloma is a group of rare and benign papillary salivary gland tumors arising from the duct system:
Basal cell adenoma is a rare, low-grade benign salivary gland neoplasm.
The salivary microbiome consists of the nonpathogenic, commensal bacteria present in the healthy human salivary glands. It differs from the oral microbiome which is located in the oral cavity. Oral microorganisms tend to adhere to teeth. The oral microbiome possesses its own characteristic microorganisms found there. Resident microbes of the mouth adhere to the teeth and gums. "[T]here may be important interactions between the saliva microbiome and other microbiomes in the human body, in particular, that of the intestinal tract."